Northwestern Vascular Symposium

CHICAGO – The next generation of hybrid carotid stents is slowly breathing life into the stagnant field of carotid artery stenting.

The new hybrid stents combine the flexibility of a traditional open-cell, nitinol stent with the stabilization typically offered by a closed-cell stent design. The initial clinical experience is limited, but shows promising results against embolization, Dr. Claudio Schönholzsaid at a symposium on vascular surgery sponsored by Northwestern University.

Last year, Dr. Schönholz and his colleagues at the Medical University of South Carolina in Charleston reported the first-in-man use of the investigational Gore Carotid Stent (W.L. Gore & Associates) (J. Endovasc. Thera. 2014;21:601-4).

As part of the Gore Carotid Stent Clinical Study for the Treatment of Carotid Artery Stenosis in Patients at Increased Risk for Adverse Events From Carotid Endarterectomy (SCAFFOLD) trial, the team has successfully treated another four patients with no evidence of peri- or postprocedural neurological events. This included a case with such severe high-grade stenosis and slow flow that the external carotid artery was not even visible on imaging before the stent was placed, Dr. Schönholz said.

The Food and Drug Administration recently reviewed unreleased data for the first 100 patients enrolled in SCAFFOLD and given the green light for the multicenter, 312-patient study to resume with the start of the new year, he said.Cristallo study (J. Endovasc. Ther. 2008;15:186-92).

A more recent retrospective study revealed only one minor stroke in the perioperative period and during the first 30 days in 68 patients with symptomatic carotid stenosis treated by Turkish surgeons with the Cristallo Ideale stent and a proximal protection device (MO.MA, Invatec s.r.l., Medtronic, Italy) (Int. Angiol. 2014 Nov. 14. [Epub ahead of print]).

Better patient selection, increased operator experience, and use of embolic protection devices has reduced neurological events associated with carotid artery stenting, but embolization still occurs after protection devices are removed due to plaque protrusion through the stent struts, Dr. Schönholz said. The unique design of the hybrid stents “may prevent plaque protrusion, eliminating peri- and postprocedural events,” he said.The Cristallo Ideale hybrid stent is a nitinol-based stent that has a closed-cell portion at its center and an open-cell configuration on the distal and proximal sections. In contrast, the Gore Carotid Stent has a closed-cell component throughout the entire device length that is created by placing an expanded polytetrafluoroethylene lattice with 500-micrometer pores over an open-cell frame. Once combined, both the stent frame and lattice are coated on all surfaces with Carmeda Bioactive Surface (CBAS) heparin. It’s action is limited only to the device surface and has no systemic anticoagulation effects, said Dr. Schönholz, who disclosed serving on Gore’s scientific advisory board.

The open-cell frame allows a high degree of flexibility and conformity to the native anatomy, while the stent lattice provides a high degree of plaque scaffolding that can reduce plaque prolapse, he said. The lattice also reduces the amount of emboli released during and after stent deployment and stabilizes the stent frame by resisting elongation as well as “fish-scaling,” or the misalignment of stent struts that protrude into the vessel wall, particularly when stents are deployed in tortuous anatomy.

Course director Dr. Mark K. Eskandari, chief of vascular surgery at Northwestern University in Chicago, said the results show that “carotid stenting isn’t dead yet and we can persevere. Advances in technology, both in regards to mechanical embolic protection devices and stent design systems, continue to improve the already great results of carotid artery stenting.”

[email protected]

CHICAGO – The next generation of hybrid carotid stents is slowly breathing life into the stagnant field of carotid artery stenting.

The new hybrid stents combine the flexibility of a traditional open-cell, nitinol stent with the stabilization typically offered by a closed-cell stent design. The initial clinical experience is limited, but shows promising results against embolization, Dr. Claudio Schönholzsaid at a symposium on vascular surgery sponsored by Northwestern University.

Last year, Dr. Schönholz and his colleagues at the Medical University of South Carolina in Charleston reported the first-in-man use of the investigational Gore Carotid Stent (W.L. Gore & Associates) (J. Endovasc. Thera. 2014;21:601-4).

As part of the Gore Carotid Stent Clinical Study for the Treatment of Carotid Artery Stenosis in Patients at Increased Risk for Adverse Events From Carotid Endarterectomy (SCAFFOLD) trial, the team has successfully treated another four patients with no evidence of peri- or postprocedural neurological events. This included a case with such severe high-grade stenosis and slow flow that the external carotid artery was not even visible on imaging before the stent was placed, Dr. Schönholz said.

The Food and Drug Administration recently reviewed unreleased data for the first 100 patients enrolled in SCAFFOLD and given the green light for the multicenter, 312-patient study to resume with the start of the new year, he said.Cristallo study (J. Endovasc. Ther. 2008;15:186-92).

A more recent retrospective study revealed only one minor stroke in the perioperative period and during the first 30 days in 68 patients with symptomatic carotid stenosis treated by Turkish surgeons with the Cristallo Ideale stent and a proximal protection device (MO.MA, Invatec s.r.l., Medtronic, Italy) (Int. Angiol. 2014 Nov. 14. [Epub ahead of print]).

Better patient selection, increased operator experience, and use of embolic protection devices has reduced neurological events associated with carotid artery stenting, but embolization still occurs after protection devices are removed due to plaque protrusion through the stent struts, Dr. Schönholz said. The unique design of the hybrid stents “may prevent plaque protrusion, eliminating peri- and postprocedural events,” he said.The Cristallo Ideale hybrid stent is a nitinol-based stent that has a closed-cell portion at its center and an open-cell configuration on the distal and proximal sections. In contrast, the Gore Carotid Stent has a closed-cell component throughout the entire device length that is created by placing an expanded polytetrafluoroethylene lattice with 500-micrometer pores over an open-cell frame. Once combined, both the stent frame and lattice are coated on all surfaces with Carmeda Bioactive Surface (CBAS) heparin. It’s action is limited only to the device surface and has no systemic anticoagulation effects, said Dr. Schönholz, who disclosed serving on Gore’s scientific advisory board.

The open-cell frame allows a high degree of flexibility and conformity to the native anatomy, while the stent lattice provides a high degree of plaque scaffolding that can reduce plaque prolapse, he said. The lattice also reduces the amount of emboli released during and after stent deployment and stabilizes the stent frame by resisting elongation as well as “fish-scaling,” or the misalignment of stent struts that protrude into the vessel wall, particularly when stents are deployed in tortuous anatomy.

Course director Dr. Mark K. Eskandari, chief of vascular surgery at Northwestern University in Chicago, said the results show that “carotid stenting isn’t dead yet and we can persevere. Advances in technology, both in regards to mechanical embolic protection devices and stent design systems, continue to improve the already great results of carotid artery stenting.”

[email protected]

CHICAGO – The next generation of hybrid carotid stents is slowly breathing life into the stagnant field of carotid artery stenting.

The new hybrid stents combine the flexibility of a traditional open-cell, nitinol stent with the stabilization typically offered by a closed-cell stent design. The initial clinical experience is limited, but shows promising results against embolization, Dr. Claudio Schönholzsaid at a symposium on vascular surgery sponsored by Northwestern University.

Last year, Dr. Schönholz and his colleagues at the Medical University of South Carolina in Charleston reported the first-in-man use of the investigational Gore Carotid Stent (W.L. Gore & Associates) (J. Endovasc. Thera. 2014;21:601-4).

As part of the Gore Carotid Stent Clinical Study for the Treatment of Carotid Artery Stenosis in Patients at Increased Risk for Adverse Events From Carotid Endarterectomy (SCAFFOLD) trial, the team has successfully treated another four patients with no evidence of peri- or postprocedural neurological events. This included a case with such severe high-grade stenosis and slow flow that the external carotid artery was not even visible on imaging before the stent was placed, Dr. Schönholz said.

The Food and Drug Administration recently reviewed unreleased data for the first 100 patients enrolled in SCAFFOLD and given the green light for the multicenter, 312-patient study to resume with the start of the new year, he said.Cristallo study (J. Endovasc. Ther. 2008;15:186-92).

A more recent retrospective study revealed only one minor stroke in the perioperative period and during the first 30 days in 68 patients with symptomatic carotid stenosis treated by Turkish surgeons with the Cristallo Ideale stent and a proximal protection device (MO.MA, Invatec s.r.l., Medtronic, Italy) (Int. Angiol. 2014 Nov. 14. [Epub ahead of print]).

Better patient selection, increased operator experience, and use of embolic protection devices has reduced neurological events associated with carotid artery stenting, but embolization still occurs after protection devices are removed due to plaque protrusion through the stent struts, Dr. Schönholz said. The unique design of the hybrid stents “may prevent plaque protrusion, eliminating peri- and postprocedural events,” he said.The Cristallo Ideale hybrid stent is a nitinol-based stent that has a closed-cell portion at its center and an open-cell configuration on the distal and proximal sections. In contrast, the Gore Carotid Stent has a closed-cell component throughout the entire device length that is created by placing an expanded polytetrafluoroethylene lattice with 500-micrometer pores over an open-cell frame. Once combined, both the stent frame and lattice are coated on all surfaces with Carmeda Bioactive Surface (CBAS) heparin. It’s action is limited only to the device surface and has no systemic anticoagulation effects, said Dr. Schönholz, who disclosed serving on Gore’s scientific advisory board.

The open-cell frame allows a high degree of flexibility and conformity to the native anatomy, while the stent lattice provides a high degree of plaque scaffolding that can reduce plaque prolapse, he said. The lattice also reduces the amount of emboli released during and after stent deployment and stabilizes the stent frame by resisting elongation as well as “fish-scaling,” or the misalignment of stent struts that protrude into the vessel wall, particularly when stents are deployed in tortuous anatomy.

Course director Dr. Mark K. Eskandari, chief of vascular surgery at Northwestern University in Chicago, said the results show that “carotid stenting isn’t dead yet and we can persevere. Advances in technology, both in regards to mechanical embolic protection devices and stent design systems, continue to improve the already great results of carotid artery stenting.”

[email protected]

CHICAGO – Successful management of infected aortic endovascular grafts requires careful operative planning and execution, meticulous postoperative care, and a fair bit of creativity.

“Each patient is different, so surgeons have to tailor the reconstructions to the individual patient and with these specific infections, have to be creative,” Dr. Thomas C. Bower, chair of vascular and endovascular surgery at Mayo Clinic, Rochester, Minn., said. “I’ve found the operations to be more challenging and more difficult than explanting portions or total graft excision when the infection has occurred in a hand-sewn graft.”

Patrice Wendling/Frontline Medical News

Unlike the typical bimodal distribution seen with hand-sewn graft infections, infection following endovascular repair of aortic aneurysms (EVAR) occurs from days up to 3 years after implantation. At the Mayo Clinic, a 79-year-old man presented with an infected endograft, psoas abscess, and Salmonella septicemia 4 years after EVAR.

“These infections are uncommon, but we are seeing more of them,” Dr. Bower said at a symposium on vascular surgery sponsored by Northwestern University.

Roughly two-thirds of patients will present with fever, nonspecific abdominal or back pain, malaise, weight loss or night sweats. If time permits, preoperative assessments include echocardiography for left ventricular function, arterial blood gases for pulmonary function since many patients are smokers, and renal ultrasound if creatinine is ≥ 1.5 mg/dL after rehydration. These tests are important because preoperative chronic obstructive pulmonary disease and renal dysfunction correlate with worse postoperative outcomes, he said.

Computed tomography angiography (CTA), however, stands as the single most important step of preoperative preparation, with the sine qua non of infection being air around the graft. Unlike hand-sewn grafts where infections can be localized, typically there is total graft involvement in these cases because the device is left inside the aneurysm sac. Aneurysms or pseudoaneurysms also have been seen above the infected device, including at the top end of suprarenal stents.

“This clearly has an impact on how we approach patients, but what’s become very apparent to me is that CTA often underestimates the amount of periaortic inflammation, especially at the juxta- and pararenal locations,” Dr. Bower said.

The Mayo group initially used in situ antibiotic-soaked prosthetic grafts for explanting EVAR devices, which yielded “acceptable mortality and reinfection rates, but primarily outstanding patency rates.” However, cryopreserved aortoiliac grafts have now become their first choice, Dr. Bower said. An ABO match is not imperative, preparation takes roughly 45 minutes, branch closures done in the lab are buttressed with sutures, and the graft is turned over to keep the lumbar arteries anterior, which offers an easy fix if there is bleeding, rather than having it on the posterior wall. Cryopreserved grafts, however, can dilate 40% and lengthen 10% under pressure.

“I’ve been burned more than once where the graft elongates more than I think, and I end up having to cut a small piece out to foreshorten it,” he said.

Reconstructions are tailored to patient anatomy. Surgeons should have several plans for reconstruction, including routing a graft through a remote path, remembering that CTA will underestimate the amount of periaortic inflammation. Separate bypasses of the renal or visceral arteries are performed first before the aortic clamp is applied to reduce physiologic stress. This requires knowledge of the supraceliac and pararenal aorta exposures, which really begins with the correct choice of incisions, Dr. Bower said. This is based on the aortic segment to be treated, position of the new graft, the aortic clamp site, and patient body habitus.

Most patients with EVAR infections are approached with a midline abdominal incision extended along the xiphoid process, which is the lynch pin for allowing upward and lateral retraction of the abdominal wall, he said. Choosing an incision that allows a more vertical orientation to where the new aortic anastomosis and clamp site will be, rather than operating in a keyhole, is important.

The second step is to open up the pararenal space by moving the viscera out of the way. This begins by ligating the inferior mesenteric vein and adjacent lymphatics, which allows incision of an avascular plane along the base of the left transverse colon. Retractor blades are set to allow the upward and lateral retraction of the small bowel, the left colon, and pancreas. Exposure of the suprarenal or supramesenteric aorta requires mobilization of the left renal vein after ligation and division of its branches.

“If that vein is intensely involved in inflammation, don’t ligate the branches in case you have to divide that vein at the caval confluence. Otherwise, you’ll run into some dysfunction of that left kidney,” Dr. Bower cautioned.

To have a secure place for the aortic cross clamp, the crura must be divided on either side of the diaphragm at or above the supramesenteric aorta, he added.

Key steps in total graft explantation are to drain abscesses prior to surgery to lower the bacterial burden and thus reduce the postoperative inflammatory response, bypass renal/visceral arteries first, if needed, remove the infected graft, debride the aorta to healthy tissue, place the new graft and cover it with omentum, and repair the bowel, if needed.

A piece of the proximal aortic wall should be sent to pathology to ensure the absence of bacteria or microabscesses. Organism-specific antibiotics are administered intravenously for 6-8 weeks followed by lifelong oral antibiotics, he said.

An earlier report involving 24 patients with infected aortic endografts (21 EVARs and 3 thoracic EVARs) treated at Mayo Clinic between 1997 and 2012 revealed polymicrobial infection in 11 patients, with methicillin-resistant Staphylococcus aureus being common. Potential contributors to infection were endovascular reintervention in eight, aortoenteric fistula/erosion in four, and various remote infections (J. Vasc. Surg. 2013;58:371-9).

Rifampin-soaked grafts were used in 15 patients, cryopreserved grafts in 4, femoral vein in 2, and axillofemoral grafts in 3. At a median of 14 months follow-up, patient survival, graft-related complications, and reinfection rates were 79%, 13%, and 4%, respectively, Dr. Bower said.

Dr. Bower reported having no financial disclosures.

[email protected]

CHICAGO – Successful management of infected aortic endovascular grafts requires careful operative planning and execution, meticulous postoperative care, and a fair bit of creativity.

“Each patient is different, so surgeons have to tailor the reconstructions to the individual patient and with these specific infections, have to be creative,” Dr. Thomas C. Bower, chair of vascular and endovascular surgery at Mayo Clinic, Rochester, Minn., said. “I’ve found the operations to be more challenging and more difficult than explanting portions or total graft excision when the infection has occurred in a hand-sewn graft.”

Patrice Wendling/Frontline Medical News

Unlike the typical bimodal distribution seen with hand-sewn graft infections, infection following endovascular repair of aortic aneurysms (EVAR) occurs from days up to 3 years after implantation. At the Mayo Clinic, a 79-year-old man presented with an infected endograft, psoas abscess, and Salmonella septicemia 4 years after EVAR.

“These infections are uncommon, but we are seeing more of them,” Dr. Bower said at a symposium on vascular surgery sponsored by Northwestern University.

Roughly two-thirds of patients will present with fever, nonspecific abdominal or back pain, malaise, weight loss or night sweats. If time permits, preoperative assessments include echocardiography for left ventricular function, arterial blood gases for pulmonary function since many patients are smokers, and renal ultrasound if creatinine is ≥ 1.5 mg/dL after rehydration. These tests are important because preoperative chronic obstructive pulmonary disease and renal dysfunction correlate with worse postoperative outcomes, he said.

Computed tomography angiography (CTA), however, stands as the single most important step of preoperative preparation, with the sine qua non of infection being air around the graft. Unlike hand-sewn grafts where infections can be localized, typically there is total graft involvement in these cases because the device is left inside the aneurysm sac. Aneurysms or pseudoaneurysms also have been seen above the infected device, including at the top end of suprarenal stents.

“This clearly has an impact on how we approach patients, but what’s become very apparent to me is that CTA often underestimates the amount of periaortic inflammation, especially at the juxta- and pararenal locations,” Dr. Bower said.

The Mayo group initially used in situ antibiotic-soaked prosthetic grafts for explanting EVAR devices, which yielded “acceptable mortality and reinfection rates, but primarily outstanding patency rates.” However, cryopreserved aortoiliac grafts have now become their first choice, Dr. Bower said. An ABO match is not imperative, preparation takes roughly 45 minutes, branch closures done in the lab are buttressed with sutures, and the graft is turned over to keep the lumbar arteries anterior, which offers an easy fix if there is bleeding, rather than having it on the posterior wall. Cryopreserved grafts, however, can dilate 40% and lengthen 10% under pressure.

“I’ve been burned more than once where the graft elongates more than I think, and I end up having to cut a small piece out to foreshorten it,” he said.

Reconstructions are tailored to patient anatomy. Surgeons should have several plans for reconstruction, including routing a graft through a remote path, remembering that CTA will underestimate the amount of periaortic inflammation. Separate bypasses of the renal or visceral arteries are performed first before the aortic clamp is applied to reduce physiologic stress. This requires knowledge of the supraceliac and pararenal aorta exposures, which really begins with the correct choice of incisions, Dr. Bower said. This is based on the aortic segment to be treated, position of the new graft, the aortic clamp site, and patient body habitus.

Most patients with EVAR infections are approached with a midline abdominal incision extended along the xiphoid process, which is the lynch pin for allowing upward and lateral retraction of the abdominal wall, he said. Choosing an incision that allows a more vertical orientation to where the new aortic anastomosis and clamp site will be, rather than operating in a keyhole, is important.

The second step is to open up the pararenal space by moving the viscera out of the way. This begins by ligating the inferior mesenteric vein and adjacent lymphatics, which allows incision of an avascular plane along the base of the left transverse colon. Retractor blades are set to allow the upward and lateral retraction of the small bowel, the left colon, and pancreas. Exposure of the suprarenal or supramesenteric aorta requires mobilization of the left renal vein after ligation and division of its branches.

“If that vein is intensely involved in inflammation, don’t ligate the branches in case you have to divide that vein at the caval confluence. Otherwise, you’ll run into some dysfunction of that left kidney,” Dr. Bower cautioned.

To have a secure place for the aortic cross clamp, the crura must be divided on either side of the diaphragm at or above the supramesenteric aorta, he added.

Key steps in total graft explantation are to drain abscesses prior to surgery to lower the bacterial burden and thus reduce the postoperative inflammatory response, bypass renal/visceral arteries first, if needed, remove the infected graft, debride the aorta to healthy tissue, place the new graft and cover it with omentum, and repair the bowel, if needed.

A piece of the proximal aortic wall should be sent to pathology to ensure the absence of bacteria or microabscesses. Organism-specific antibiotics are administered intravenously for 6-8 weeks followed by lifelong oral antibiotics, he said.

An earlier report involving 24 patients with infected aortic endografts (21 EVARs and 3 thoracic EVARs) treated at Mayo Clinic between 1997 and 2012 revealed polymicrobial infection in 11 patients, with methicillin-resistant Staphylococcus aureus being common. Potential contributors to infection were endovascular reintervention in eight, aortoenteric fistula/erosion in four, and various remote infections (J. Vasc. Surg. 2013;58:371-9).

Rifampin-soaked grafts were used in 15 patients, cryopreserved grafts in 4, femoral vein in 2, and axillofemoral grafts in 3. At a median of 14 months follow-up, patient survival, graft-related complications, and reinfection rates were 79%, 13%, and 4%, respectively, Dr. Bower said.

Dr. Bower reported having no financial disclosures.

[email protected]

CHICAGO – Successful management of infected aortic endovascular grafts requires careful operative planning and execution, meticulous postoperative care, and a fair bit of creativity.

“Each patient is different, so surgeons have to tailor the reconstructions to the individual patient and with these specific infections, have to be creative,” Dr. Thomas C. Bower, chair of vascular and endovascular surgery at Mayo Clinic, Rochester, Minn., said. “I’ve found the operations to be more challenging and more difficult than explanting portions or total graft excision when the infection has occurred in a hand-sewn graft.”

Patrice Wendling/Frontline Medical News

Unlike the typical bimodal distribution seen with hand-sewn graft infections, infection following endovascular repair of aortic aneurysms (EVAR) occurs from days up to 3 years after implantation. At the Mayo Clinic, a 79-year-old man presented with an infected endograft, psoas abscess, and Salmonella septicemia 4 years after EVAR.

“These infections are uncommon, but we are seeing more of them,” Dr. Bower said at a symposium on vascular surgery sponsored by Northwestern University.

Roughly two-thirds of patients will present with fever, nonspecific abdominal or back pain, malaise, weight loss or night sweats. If time permits, preoperative assessments include echocardiography for left ventricular function, arterial blood gases for pulmonary function since many patients are smokers, and renal ultrasound if creatinine is ≥ 1.5 mg/dL after rehydration. These tests are important because preoperative chronic obstructive pulmonary disease and renal dysfunction correlate with worse postoperative outcomes, he said.

Computed tomography angiography (CTA), however, stands as the single most important step of preoperative preparation, with the sine qua non of infection being air around the graft. Unlike hand-sewn grafts where infections can be localized, typically there is total graft involvement in these cases because the device is left inside the aneurysm sac. Aneurysms or pseudoaneurysms also have been seen above the infected device, including at the top end of suprarenal stents.

“This clearly has an impact on how we approach patients, but what’s become very apparent to me is that CTA often underestimates the amount of periaortic inflammation, especially at the juxta- and pararenal locations,” Dr. Bower said.

The Mayo group initially used in situ antibiotic-soaked prosthetic grafts for explanting EVAR devices, which yielded “acceptable mortality and reinfection rates, but primarily outstanding patency rates.” However, cryopreserved aortoiliac grafts have now become their first choice, Dr. Bower said. An ABO match is not imperative, preparation takes roughly 45 minutes, branch closures done in the lab are buttressed with sutures, and the graft is turned over to keep the lumbar arteries anterior, which offers an easy fix if there is bleeding, rather than having it on the posterior wall. Cryopreserved grafts, however, can dilate 40% and lengthen 10% under pressure.

“I’ve been burned more than once where the graft elongates more than I think, and I end up having to cut a small piece out to foreshorten it,” he said.

Reconstructions are tailored to patient anatomy. Surgeons should have several plans for reconstruction, including routing a graft through a remote path, remembering that CTA will underestimate the amount of periaortic inflammation. Separate bypasses of the renal or visceral arteries are performed first before the aortic clamp is applied to reduce physiologic stress. This requires knowledge of the supraceliac and pararenal aorta exposures, which really begins with the correct choice of incisions, Dr. Bower said. This is based on the aortic segment to be treated, position of the new graft, the aortic clamp site, and patient body habitus.

Most patients with EVAR infections are approached with a midline abdominal incision extended along the xiphoid process, which is the lynch pin for allowing upward and lateral retraction of the abdominal wall, he said. Choosing an incision that allows a more vertical orientation to where the new aortic anastomosis and clamp site will be, rather than operating in a keyhole, is important.

The second step is to open up the pararenal space by moving the viscera out of the way. This begins by ligating the inferior mesenteric vein and adjacent lymphatics, which allows incision of an avascular plane along the base of the left transverse colon. Retractor blades are set to allow the upward and lateral retraction of the small bowel, the left colon, and pancreas. Exposure of the suprarenal or supramesenteric aorta requires mobilization of the left renal vein after ligation and division of its branches.

“If that vein is intensely involved in inflammation, don’t ligate the branches in case you have to divide that vein at the caval confluence. Otherwise, you’ll run into some dysfunction of that left kidney,” Dr. Bower cautioned.

To have a secure place for the aortic cross clamp, the crura must be divided on either side of the diaphragm at or above the supramesenteric aorta, he added.

Key steps in total graft explantation are to drain abscesses prior to surgery to lower the bacterial burden and thus reduce the postoperative inflammatory response, bypass renal/visceral arteries first, if needed, remove the infected graft, debride the aorta to healthy tissue, place the new graft and cover it with omentum, and repair the bowel, if needed.

A piece of the proximal aortic wall should be sent to pathology to ensure the absence of bacteria or microabscesses. Organism-specific antibiotics are administered intravenously for 6-8 weeks followed by lifelong oral antibiotics, he said.

An earlier report involving 24 patients with infected aortic endografts (21 EVARs and 3 thoracic EVARs) treated at Mayo Clinic between 1997 and 2012 revealed polymicrobial infection in 11 patients, with methicillin-resistant Staphylococcus aureus being common. Potential contributors to infection were endovascular reintervention in eight, aortoenteric fistula/erosion in four, and various remote infections (J. Vasc. Surg. 2013;58:371-9).

Rifampin-soaked grafts were used in 15 patients, cryopreserved grafts in 4, femoral vein in 2, and axillofemoral grafts in 3. At a median of 14 months follow-up, patient survival, graft-related complications, and reinfection rates were 79%, 13%, and 4%, respectively, Dr. Bower said.

Dr. Bower reported having no financial disclosures.

[email protected]

CHICAGO – Real-world experience with novel endografts like the Ovation Prime abdominal endograft system is prompting some vascular specialists to rethink such central abdominal aortic aneurysm tenets as aortic neck dilation and minimum neck size.

“We started using this in our worst cases, patients with small caliber access vessels and very short aortic necks, to test this device, but over time we’ve pretty much made this our workhorse graft based on our outcomes,” Dr. Syed Hussain of the University of Illinois at Champaign-Urbana, said at a vascular surgery symposium sponsored by Northwestern University.

Patrice Wendling/Frontline Medical News

Among 67 patients with AAAs treated since the team’s first implant in November 2012, the technical success rate is 100%. At baseline, 35% of patients had access vessels < 7 mm, 45% had short aortic neck (< 15 mm), 60% had moderate to severe calcification (> 25% circumferential), and half had moderate to severe thrombus (> 25% circumferential).

The Ovation Prime (TriVascular Technologies) device is relatively quick and easy to put in, with an average procedure time of only 33 minutes, he said. Access was percutaneous in 27%, average blood loss was minimal at 60 mL, and average hospital stay was 1.7 days.

Two patients with severe comorbidities were admitted to the ICU and two patients experienced intraoperative type 1a endoleaks, both successfully treated with a Palmaz stent.

After an average follow-up of 12 months, there have been no type 1, III or IV endoleaks, graft migration, aneurysm enlargement, conversions, ruptures, limb occlusions, or secondary procedures, said Dr. Hussain, who disclosed serving as a consultant for Trivascular and national principal investigator of the PostMarket Ovation Trial. There were 12 type II endoleaks (17%) and all have been clinically irrelevant.

Because of the Ovation’s novel O-ring sealing mechanism, “you get a pretty watertight seal ring on these patients,” he said. More importantly, shear stress is distributed evenly along the entire O-ring, which creates very minimal outward stress on the aorta, “maybe 2 or 3 atmospheres at best.”

Evidence continues to build that self-expandable stents place chronic outward stress on the aorta that causes degeneration of the aortic wall, resulting in eventual aortic neck dilation and endograft migration. While it’s been argued that disease progression leads to aortic dilation, the phenomenon took off after the arrival of endovascular stents, not during decades of open AAA repair, Dr. Hussain, also of the Vein & Vascular Center at the Christie Clinic in Champaign, said.

In the Ovation approval trial, proximal neck dilation at 2 years followed a similar curve in the Ovation and open repair cohorts, compared with those for the more traditional endografts, he noted.

The Ovation Prime system was approved in 2012 and in mid-2014, the Food and Drug Administration approved changes to the indication statement that eliminated the requirement for a minimal aortic neck length.

Essentially, the Ovation device can be placed in any patient if the diameter at 13 mm below the lowest renal artery (the site of the most proximal sealing ring) is within the treatable diameter range of the device (15.8 mm-30.4 mm), Dr. Hussain said.

“The idea of having a neck length is completely starting to go away,” he said. “And even though the trial by Endologix is looking at 1 centimeter as the current requirement for enrolling patients, I think eventually it’s going to get to the point where you’re not going to need a neck for the Nellix device either. You’re going to be able to treat patients who have very short, 1 to 2 millimeter necks, basically perirenal aneurysms, and get a seal on.”

The Nellix endovascular aneurysm sealing system (Endologix) is not commercially available in the U.S., but is the being evaluated in at least three studies. It consists of dual balloon-expandable end-frames surrounded by polymer-filled endobags and is designed to completely fill and seal the aortic aneurysm sac. Anatomical requirements for patients to be enrolled in clinical studies include a nonaneurysmal aortic neck length of ≥ 10 mm, nonaneurysmal aortic neck diameter of 18 mm-32 mm, maximum aortic blood flow lumen diameter of ≤ 60 mm, and common iliac artery diameter of 8 mm-35 mm, according to the company’s website.

[email protected]

CHICAGO – Real-world experience with novel endografts like the Ovation Prime abdominal endograft system is prompting some vascular specialists to rethink such central abdominal aortic aneurysm tenets as aortic neck dilation and minimum neck size.

“We started using this in our worst cases, patients with small caliber access vessels and very short aortic necks, to test this device, but over time we’ve pretty much made this our workhorse graft based on our outcomes,” Dr. Syed Hussain of the University of Illinois at Champaign-Urbana, said at a vascular surgery symposium sponsored by Northwestern University.

Patrice Wendling/Frontline Medical News

Among 67 patients with AAAs treated since the team’s first implant in November 2012, the technical success rate is 100%. At baseline, 35% of patients had access vessels < 7 mm, 45% had short aortic neck (< 15 mm), 60% had moderate to severe calcification (> 25% circumferential), and half had moderate to severe thrombus (> 25% circumferential).

The Ovation Prime (TriVascular Technologies) device is relatively quick and easy to put in, with an average procedure time of only 33 minutes, he said. Access was percutaneous in 27%, average blood loss was minimal at 60 mL, and average hospital stay was 1.7 days.

Two patients with severe comorbidities were admitted to the ICU and two patients experienced intraoperative type 1a endoleaks, both successfully treated with a Palmaz stent.

After an average follow-up of 12 months, there have been no type 1, III or IV endoleaks, graft migration, aneurysm enlargement, conversions, ruptures, limb occlusions, or secondary procedures, said Dr. Hussain, who disclosed serving as a consultant for Trivascular and national principal investigator of the PostMarket Ovation Trial. There were 12 type II endoleaks (17%) and all have been clinically irrelevant.

Because of the Ovation’s novel O-ring sealing mechanism, “you get a pretty watertight seal ring on these patients,” he said. More importantly, shear stress is distributed evenly along the entire O-ring, which creates very minimal outward stress on the aorta, “maybe 2 or 3 atmospheres at best.”

Evidence continues to build that self-expandable stents place chronic outward stress on the aorta that causes degeneration of the aortic wall, resulting in eventual aortic neck dilation and endograft migration. While it’s been argued that disease progression leads to aortic dilation, the phenomenon took off after the arrival of endovascular stents, not during decades of open AAA repair, Dr. Hussain, also of the Vein & Vascular Center at the Christie Clinic in Champaign, said.

In the Ovation approval trial, proximal neck dilation at 2 years followed a similar curve in the Ovation and open repair cohorts, compared with those for the more traditional endografts, he noted.

The Ovation Prime system was approved in 2012 and in mid-2014, the Food and Drug Administration approved changes to the indication statement that eliminated the requirement for a minimal aortic neck length.

Essentially, the Ovation device can be placed in any patient if the diameter at 13 mm below the lowest renal artery (the site of the most proximal sealing ring) is within the treatable diameter range of the device (15.8 mm-30.4 mm), Dr. Hussain said.

“The idea of having a neck length is completely starting to go away,” he said. “And even though the trial by Endologix is looking at 1 centimeter as the current requirement for enrolling patients, I think eventually it’s going to get to the point where you’re not going to need a neck for the Nellix device either. You’re going to be able to treat patients who have very short, 1 to 2 millimeter necks, basically perirenal aneurysms, and get a seal on.”

The Nellix endovascular aneurysm sealing system (Endologix) is not commercially available in the U.S., but is the being evaluated in at least three studies. It consists of dual balloon-expandable end-frames surrounded by polymer-filled endobags and is designed to completely fill and seal the aortic aneurysm sac. Anatomical requirements for patients to be enrolled in clinical studies include a nonaneurysmal aortic neck length of ≥ 10 mm, nonaneurysmal aortic neck diameter of 18 mm-32 mm, maximum aortic blood flow lumen diameter of ≤ 60 mm, and common iliac artery diameter of 8 mm-35 mm, according to the company’s website.

[email protected]

CHICAGO – Real-world experience with novel endografts like the Ovation Prime abdominal endograft system is prompting some vascular specialists to rethink such central abdominal aortic aneurysm tenets as aortic neck dilation and minimum neck size.

“We started using this in our worst cases, patients with small caliber access vessels and very short aortic necks, to test this device, but over time we’ve pretty much made this our workhorse graft based on our outcomes,” Dr. Syed Hussain of the University of Illinois at Champaign-Urbana, said at a vascular surgery symposium sponsored by Northwestern University.

Patrice Wendling/Frontline Medical News

Among 67 patients with AAAs treated since the team’s first implant in November 2012, the technical success rate is 100%. At baseline, 35% of patients had access vessels < 7 mm, 45% had short aortic neck (< 15 mm), 60% had moderate to severe calcification (> 25% circumferential), and half had moderate to severe thrombus (> 25% circumferential).

The Ovation Prime (TriVascular Technologies) device is relatively quick and easy to put in, with an average procedure time of only 33 minutes, he said. Access was percutaneous in 27%, average blood loss was minimal at 60 mL, and average hospital stay was 1.7 days.

Two patients with severe comorbidities were admitted to the ICU and two patients experienced intraoperative type 1a endoleaks, both successfully treated with a Palmaz stent.

After an average follow-up of 12 months, there have been no type 1, III or IV endoleaks, graft migration, aneurysm enlargement, conversions, ruptures, limb occlusions, or secondary procedures, said Dr. Hussain, who disclosed serving as a consultant for Trivascular and national principal investigator of the PostMarket Ovation Trial. There were 12 type II endoleaks (17%) and all have been clinically irrelevant.

Because of the Ovation’s novel O-ring sealing mechanism, “you get a pretty watertight seal ring on these patients,” he said. More importantly, shear stress is distributed evenly along the entire O-ring, which creates very minimal outward stress on the aorta, “maybe 2 or 3 atmospheres at best.”

Evidence continues to build that self-expandable stents place chronic outward stress on the aorta that causes degeneration of the aortic wall, resulting in eventual aortic neck dilation and endograft migration. While it’s been argued that disease progression leads to aortic dilation, the phenomenon took off after the arrival of endovascular stents, not during decades of open AAA repair, Dr. Hussain, also of the Vein & Vascular Center at the Christie Clinic in Champaign, said.

In the Ovation approval trial, proximal neck dilation at 2 years followed a similar curve in the Ovation and open repair cohorts, compared with those for the more traditional endografts, he noted.

The Ovation Prime system was approved in 2012 and in mid-2014, the Food and Drug Administration approved changes to the indication statement that eliminated the requirement for a minimal aortic neck length.

Essentially, the Ovation device can be placed in any patient if the diameter at 13 mm below the lowest renal artery (the site of the most proximal sealing ring) is within the treatable diameter range of the device (15.8 mm-30.4 mm), Dr. Hussain said.

“The idea of having a neck length is completely starting to go away,” he said. “And even though the trial by Endologix is looking at 1 centimeter as the current requirement for enrolling patients, I think eventually it’s going to get to the point where you’re not going to need a neck for the Nellix device either. You’re going to be able to treat patients who have very short, 1 to 2 millimeter necks, basically perirenal aneurysms, and get a seal on.”

The Nellix endovascular aneurysm sealing system (Endologix) is not commercially available in the U.S., but is the being evaluated in at least three studies. It consists of dual balloon-expandable end-frames surrounded by polymer-filled endobags and is designed to completely fill and seal the aortic aneurysm sac. Anatomical requirements for patients to be enrolled in clinical studies include a nonaneurysmal aortic neck length of ≥ 10 mm, nonaneurysmal aortic neck diameter of 18 mm-32 mm, maximum aortic blood flow lumen diameter of ≤ 60 mm, and common iliac artery diameter of 8 mm-35 mm, according to the company’s website.

[email protected]

CHICAGO – Portal vein recanalization using a transsplenic approach can be utilized to improve transplant candidacy in patients with cirrhosis and chronic portal vein thrombosis, according to Dr. Bartley Thornburg.

“It’s a safe and effective procedure that allows for end-to-end anastomoses at transplant in patients who otherwise would not be able to have them or would require thrombectomy without transplant, and we know that end-to-end anastomoses are associated with decreased morbidity and mortality,” said Dr. Thornburg of Northwestern University Medical Center in Chicago.

Historically, and at his institution, portal vein thrombosis (PVT) is a relative contraindication to liver transplant. The American Association for the Study of Liver Diseases also recommends that transjugular intrahepatic portosystemic shunt (TIPS) placement be avoided in patients with a Model for End-State Liver Disease (MELD) score >18.

Patrice Wendling/Frontline Medical News

In 2013, colleague Dr. Riad Salem demonstrated the efficacy of portal vein recanalization during TIPS using a transhepatic approach in 44 patients, with only one technical failure and three cases of rethrombosis. Among six patients with a baseline MELD score >18, four went on to successful liver transplant, one is awaiting transplant, and one died as a result of bleeding 45 days post procedure despite an improvement in MELD score.

The last three patients in the series underwent TIPS with a transsplenic approach, and not only were the results equally good, but the approach was technically easier, Dr. Thornburg said at a symposium on vascular surgery sponsored by Northwestern University.

Since then, this increasingly common alternative approach has been assessed in another 11 consecutive patients with cirrhosis, portal hypertension, and chronic PVT. All patients had been denied listing for transplant because of their PVT, and four had a baseline MELD score >18.

At the end of the procedure, thrombus persisted in 45% (5 of 11 patients). On a 1-month follow-up venogram, however, three of the five patients had complete resolution of the thrombus without any added anticoagulation, one had persistent partial thrombus that was smaller than at stent placement, and one went on to transplant, Dr. Thornburg said.

All six of the patients with portal vein (PV) patency post procedure have retained patency after a median follow-up of 6.4 months.

“What we’ve learned from doing these cases is that complete elimination of the portal vein thrombus at the time of TIPS placement isn’t necessary,” he said. “It would be easy to get carried away and do suction or AngioJet [mechanical thrombectomy], but what we’ve found is that because of how much flow there is in the portal vein once it’s recanalized and the TIPS is in place, basically establishing a flow allowed for clot clearance by 1 month in all patients, except one.”

The procedure starts like a typical TIPS, with access achieved by advancing a 21-guage needle into the peripheral splenic vein or hilum under ultrasound guidance. A 5-French sheath is then placed through the parenchyma to the origin of splenic vein or the clot and an intrahepatic venogram performed to confirm occlusion, Dr. Thornburg said.

A 5-French Kumpe catheter and glide wire are used to recanalize the thrombosed portal vein, with a 10-mm gooseneck snare placed through the Kumpe in the peripheral portal vein as a target for the TIPS needle.

“Then, we basically get through-and-through access from the IJ [internal jugular] through this splenic access, and that gives us the workability to get our sheath across the portal vein and place our TIPS,” he said.

The remainder of the procedure is similar to that of the transhepatic approach. Angioplasty of the thrombosed PV is performed with an 8-by-40-mm balloon, followed by deployment of a Viatorr stent graft. The stent and PV are dilated with a 10-by-40-mm balloon and the splenic tract embolized with a couple of 4-by-14-cm Nester coils.

Based on their experience, short TIPS are always placed to maximize the amount of portal vein that is available at transplant for the end-to-end anastomoses, Dr. Thornburg said.

All patients who went on to transplant have received end-to-end anastomoses on what transplant surgeons have described as “totally normal” walled portal veins, including one patient who underwent transplant just 1 week post TIPS, he added.

There have been no major bleeding events with the transsplenic approach and only two adverse events: one case of transient encephalopathy and one low-grade fever.

Dr. Thornburg and Dr. Salem reported having no relevant financial disclosures.

[email protected]

CHICAGO – Portal vein recanalization using a transsplenic approach can be utilized to improve transplant candidacy in patients with cirrhosis and chronic portal vein thrombosis, according to Dr. Bartley Thornburg.

“It’s a safe and effective procedure that allows for end-to-end anastomoses at transplant in patients who otherwise would not be able to have them or would require thrombectomy without transplant, and we know that end-to-end anastomoses are associated with decreased morbidity and mortality,” said Dr. Thornburg of Northwestern University Medical Center in Chicago.

Historically, and at his institution, portal vein thrombosis (PVT) is a relative contraindication to liver transplant. The American Association for the Study of Liver Diseases also recommends that transjugular intrahepatic portosystemic shunt (TIPS) placement be avoided in patients with a Model for End-State Liver Disease (MELD) score >18.

Patrice Wendling/Frontline Medical News

In 2013, colleague Dr. Riad Salem demonstrated the efficacy of portal vein recanalization during TIPS using a transhepatic approach in 44 patients, with only one technical failure and three cases of rethrombosis. Among six patients with a baseline MELD score >18, four went on to successful liver transplant, one is awaiting transplant, and one died as a result of bleeding 45 days post procedure despite an improvement in MELD score.

The last three patients in the series underwent TIPS with a transsplenic approach, and not only were the results equally good, but the approach was technically easier, Dr. Thornburg said at a symposium on vascular surgery sponsored by Northwestern University.

Since then, this increasingly common alternative approach has been assessed in another 11 consecutive patients with cirrhosis, portal hypertension, and chronic PVT. All patients had been denied listing for transplant because of their PVT, and four had a baseline MELD score >18.

At the end of the procedure, thrombus persisted in 45% (5 of 11 patients). On a 1-month follow-up venogram, however, three of the five patients had complete resolution of the thrombus without any added anticoagulation, one had persistent partial thrombus that was smaller than at stent placement, and one went on to transplant, Dr. Thornburg said.

All six of the patients with portal vein (PV) patency post procedure have retained patency after a median follow-up of 6.4 months.

“What we’ve learned from doing these cases is that complete elimination of the portal vein thrombus at the time of TIPS placement isn’t necessary,” he said. “It would be easy to get carried away and do suction or AngioJet [mechanical thrombectomy], but what we’ve found is that because of how much flow there is in the portal vein once it’s recanalized and the TIPS is in place, basically establishing a flow allowed for clot clearance by 1 month in all patients, except one.”

The procedure starts like a typical TIPS, with access achieved by advancing a 21-guage needle into the peripheral splenic vein or hilum under ultrasound guidance. A 5-French sheath is then placed through the parenchyma to the origin of splenic vein or the clot and an intrahepatic venogram performed to confirm occlusion, Dr. Thornburg said.

A 5-French Kumpe catheter and glide wire are used to recanalize the thrombosed portal vein, with a 10-mm gooseneck snare placed through the Kumpe in the peripheral portal vein as a target for the TIPS needle.

“Then, we basically get through-and-through access from the IJ [internal jugular] through this splenic access, and that gives us the workability to get our sheath across the portal vein and place our TIPS,” he said.

The remainder of the procedure is similar to that of the transhepatic approach. Angioplasty of the thrombosed PV is performed with an 8-by-40-mm balloon, followed by deployment of a Viatorr stent graft. The stent and PV are dilated with a 10-by-40-mm balloon and the splenic tract embolized with a couple of 4-by-14-cm Nester coils.

Based on their experience, short TIPS are always placed to maximize the amount of portal vein that is available at transplant for the end-to-end anastomoses, Dr. Thornburg said.

All patients who went on to transplant have received end-to-end anastomoses on what transplant surgeons have described as “totally normal” walled portal veins, including one patient who underwent transplant just 1 week post TIPS, he added.

There have been no major bleeding events with the transsplenic approach and only two adverse events: one case of transient encephalopathy and one low-grade fever.

Dr. Thornburg and Dr. Salem reported having no relevant financial disclosures.

[email protected]

CHICAGO – Portal vein recanalization using a transsplenic approach can be utilized to improve transplant candidacy in patients with cirrhosis and chronic portal vein thrombosis, according to Dr. Bartley Thornburg.

“It’s a safe and effective procedure that allows for end-to-end anastomoses at transplant in patients who otherwise would not be able to have them or would require thrombectomy without transplant, and we know that end-to-end anastomoses are associated with decreased morbidity and mortality,” said Dr. Thornburg of Northwestern University Medical Center in Chicago.

Historically, and at his institution, portal vein thrombosis (PVT) is a relative contraindication to liver transplant. The American Association for the Study of Liver Diseases also recommends that transjugular intrahepatic portosystemic shunt (TIPS) placement be avoided in patients with a Model for End-State Liver Disease (MELD) score >18.

Patrice Wendling/Frontline Medical News

In 2013, colleague Dr. Riad Salem demonstrated the efficacy of portal vein recanalization during TIPS using a transhepatic approach in 44 patients, with only one technical failure and three cases of rethrombosis. Among six patients with a baseline MELD score >18, four went on to successful liver transplant, one is awaiting transplant, and one died as a result of bleeding 45 days post procedure despite an improvement in MELD score.

The last three patients in the series underwent TIPS with a transsplenic approach, and not only were the results equally good, but the approach was technically easier, Dr. Thornburg said at a symposium on vascular surgery sponsored by Northwestern University.

Since then, this increasingly common alternative approach has been assessed in another 11 consecutive patients with cirrhosis, portal hypertension, and chronic PVT. All patients had been denied listing for transplant because of their PVT, and four had a baseline MELD score >18.

At the end of the procedure, thrombus persisted in 45% (5 of 11 patients). On a 1-month follow-up venogram, however, three of the five patients had complete resolution of the thrombus without any added anticoagulation, one had persistent partial thrombus that was smaller than at stent placement, and one went on to transplant, Dr. Thornburg said.

All six of the patients with portal vein (PV) patency post procedure have retained patency after a median follow-up of 6.4 months.

“What we’ve learned from doing these cases is that complete elimination of the portal vein thrombus at the time of TIPS placement isn’t necessary,” he said. “It would be easy to get carried away and do suction or AngioJet [mechanical thrombectomy], but what we’ve found is that because of how much flow there is in the portal vein once it’s recanalized and the TIPS is in place, basically establishing a flow allowed for clot clearance by 1 month in all patients, except one.”

The procedure starts like a typical TIPS, with access achieved by advancing a 21-guage needle into the peripheral splenic vein or hilum under ultrasound guidance. A 5-French sheath is then placed through the parenchyma to the origin of splenic vein or the clot and an intrahepatic venogram performed to confirm occlusion, Dr. Thornburg said.

A 5-French Kumpe catheter and glide wire are used to recanalize the thrombosed portal vein, with a 10-mm gooseneck snare placed through the Kumpe in the peripheral portal vein as a target for the TIPS needle.

“Then, we basically get through-and-through access from the IJ [internal jugular] through this splenic access, and that gives us the workability to get our sheath across the portal vein and place our TIPS,” he said.

The remainder of the procedure is similar to that of the transhepatic approach. Angioplasty of the thrombosed PV is performed with an 8-by-40-mm balloon, followed by deployment of a Viatorr stent graft. The stent and PV are dilated with a 10-by-40-mm balloon and the splenic tract embolized with a couple of 4-by-14-cm Nester coils.

Based on their experience, short TIPS are always placed to maximize the amount of portal vein that is available at transplant for the end-to-end anastomoses, Dr. Thornburg said.

All patients who went on to transplant have received end-to-end anastomoses on what transplant surgeons have described as “totally normal” walled portal veins, including one patient who underwent transplant just 1 week post TIPS, he added.

There have been no major bleeding events with the transsplenic approach and only two adverse events: one case of transient encephalopathy and one low-grade fever.

Dr. Thornburg and Dr. Salem reported having no relevant financial disclosures.

[email protected]

CHICAGO – Implementation of preoperative venous thromboembolism prophylaxis requires a highly individualized approach and a little boost from information technology, one expert suggested.

“What may not be appreciated by some vascular surgeons is that for certain procedures we do, our patients actually have a high VTE [venous thromboembolism] risk. I know people think, ‘We use heparin, so our patients aren’t at high risk,’ but they actually are,” Dr. Melina Kibbe said at a symposium on vascular surgery sponsored by Northwestern University.

The VTE risk is 4.2% for open thoracoabdominal aortic aneurysm repair and 2.2% for thoracic endovascular aortic repair in the American College of Surgeons National Surgical Quality Improvement Program database. That may be an underestimation, however, because the NSQIP database captures only symptomatic events documented by imaging and those events occurring in the first 30 days after surgery.

Patrice Wendling/Frontline Medical News

Smaller studies looking at the problem prospectively suggest the VTE risk is closer to 2%-12% after open aortic surgery and 5.3% after endovascular aortic repair, she said.

Add to that the U.S. Surgeon General’s 2008 call to action to prevent VTE and the Institute of Medicine’s stance that failure to provide VTE prophylaxis qualifies as a medical error, and it would be tempting for vascular surgeons to prescribe pharmacologic prophylaxis for all of their patients, or at least do so based on the type of procedure.

“But VTE formation is really secondary to patient-specific and procedure-related factors,” said Dr. Kibbe, a professor of vascular surgery at Northwestern University in Chicago.

She highlighted five current VTE risk assessment models (RAMs) and the potential returns when RAMs are incorporated into clinical decision support systems.

• Kucher model. One of the earlier and most straightforward RAMs is the Kucher model. It assessed eight weighted risk factors (advanced age, obesity, bed rest, hormone replacement therapy/oral contraceptives, major surgery, cancer, prior VTE, and hypercoagulability) and provided surgeons with electronic alerts regarding prophylaxis.

VTE rates dropped from 8.2% to 4.9% in the high-risk category (score ≥ 4) with the use of the simple physician reminders (N. Engl. J. Med. 2005;352:969-77). Prospective validation showed that VTE increased proportionally with higher scores, Dr. Kibbe said. On the other hand, the model lacked sensitivity at low VTE risk, because 20% of patients with a score of 4 or less actually had VTEs.

“So, while it was simple, it only works well for the high-risk category,” she said.

• Rogers model. One of the most vigorously studied and developed RAMs is the Rogers model (J. Am. Coll. Surg. 2007;204:1211-21). It identified 15 variables (including lab values, patient characteristics, disease states, work relative-value unit, and type of operation) that were independently associated with VTE formation among 183,609 patients undergoing general, vascular, or thoracic procedures at 142 Veterans Health Administration and private hospitals. Each variable is assigned a value from 0 to 9 and added together to create a Rogers score.

Validation showed that VTE risk correlates with the Rogers score, rising from 0.11% for patients with a low score (< 7) to 1.32% for those with a high score (> 10), Dr. Kibbe said. Criticisms of the model are that it is complex, VTE incidence in the entire cohort was low at just 0.63%, the type of VTE prophylaxis used was unclear, and the model lacks prospective validation in a vascular surgery cohort.

• Caprini model. The most commonly used RAM is the 2005 Caprini model (Dis. Mon. 2005;51:70-8), which assigns a weighted score based on more than 30 VTE risk factors compiled by the authors. It has been prospectively validated in numerous studies and shown to accurately stratify 30-day VTE risk at 0.5% for patients at very low risk, 1.5% for low risk, 3% for moderate risk, and 6% for high risk.

The Caprini model, however, was not developed with the same rigor as the Rogers RAM, some of the risk factors have been shown not to be a risk for VTE, and it is complex, Dr. Kibbe observed.

• Pannucci model. The Pannucci model was created specifically to counteract the complexity of the Rogers and Caprini RAMs and incorporates only seven risk factors (personal history of VTE, current cancer, age ≥ 60 years, body mass index ≥ 40 kg/m², male sex, sepsis/septic shock/systemic inflammatory response syndrome, and family history of VTE) into a weighted index for 90-day VTE risk (Chest 2014;145:567-73). The model was developed using a statewide database and a derivation cohort made up of 20% vascular surgery patients.

Both the derivation and validation cohorts identified an 18-fold variation in VTE risk from the lowest- to highest-risk surgical population, showing that the model stratifies patients correctly. Further prospective validation is needed, Dr. Kibbe said.

• Scarborough model. Finally, in an attempt to develop a RAM specific to vascular surgery patients, Dr. John Scarborough and colleagues examined 6,035 patients undergoing open AAA repair in the NSQIP database. The 30-day VTE rate was 2.4% for the entire cohort. Eight independent perioperative risk factors were identified and used to create a nonweighted scoring system (J. Am. Coll. Surg. 2012;214:620-6).

Overall, 65% of patients had 0-1 risk factor and a VTE incidence of 1.5%, while 15% had 3 or more risk factors and a VTE incidence of 6.1%. The Scarborough model has good risk stratification, Dr. Kibbe said, but it is limited by the aforementioned criticisms regarding the NSQIP database, and it also needs prospective validation.

“We all know that proper VTE prophylaxis is very important for our patients; but we need mechanisms by which the attention given to this need for prophylaxis, which is a lot, is turned into proper implementation,” she said.

For Dr. Kibbe and her colleagues, proper implementation meant developing a RAM that was incorporated into the electronic medical record system for all surgical patients at the Jesse Brown VA Medical Center in Chicago. Clinicians were prompted to complete the RAM upon placing orders for preanesthesia testing clearance, and the clinical decision support system would provide a recommended prophylaxis regimen and easily selected electronic orders that could be signed.

A pre- and postimplementation analysis involving 400 consecutive patients revealed an 82% increase in patients with preoperative VTE prophylaxis ordered (22% vs. 40%), a 75% decrease in inappropriate cancellation of orders more than 12 hours before surgery (37% vs. 9%), and a nearly sevenfold increase in the number of patients receiving pharmacologic and mechanical prophylaxis (5% vs. 32%), she said. There was an 80% and 36% decline in DVT rates at 30 and 90 days postoperative, but event rates were too low to detect a significant difference (J. Vasc. Surg. 2010;51:648-54).

Dr. Kibbe reported having no financial disclosures.

[email protected]

CHICAGO – Implementation of preoperative venous thromboembolism prophylaxis requires a highly individualized approach and a little boost from information technology, one expert suggested.

“What may not be appreciated by some vascular surgeons is that for certain procedures we do, our patients actually have a high VTE [venous thromboembolism] risk. I know people think, ‘We use heparin, so our patients aren’t at high risk,’ but they actually are,” Dr. Melina Kibbe said at a symposium on vascular surgery sponsored by Northwestern University.

The VTE risk is 4.2% for open thoracoabdominal aortic aneurysm repair and 2.2% for thoracic endovascular aortic repair in the American College of Surgeons National Surgical Quality Improvement Program database. That may be an underestimation, however, because the NSQIP database captures only symptomatic events documented by imaging and those events occurring in the first 30 days after surgery.

Patrice Wendling/Frontline Medical News

Smaller studies looking at the problem prospectively suggest the VTE risk is closer to 2%-12% after open aortic surgery and 5.3% after endovascular aortic repair, she said.

Add to that the U.S. Surgeon General’s 2008 call to action to prevent VTE and the Institute of Medicine’s stance that failure to provide VTE prophylaxis qualifies as a medical error, and it would be tempting for vascular surgeons to prescribe pharmacologic prophylaxis for all of their patients, or at least do so based on the type of procedure.

“But VTE formation is really secondary to patient-specific and procedure-related factors,” said Dr. Kibbe, a professor of vascular surgery at Northwestern University in Chicago.

She highlighted five current VTE risk assessment models (RAMs) and the potential returns when RAMs are incorporated into clinical decision support systems.

• Kucher model. One of the earlier and most straightforward RAMs is the Kucher model. It assessed eight weighted risk factors (advanced age, obesity, bed rest, hormone replacement therapy/oral contraceptives, major surgery, cancer, prior VTE, and hypercoagulability) and provided surgeons with electronic alerts regarding prophylaxis.

VTE rates dropped from 8.2% to 4.9% in the high-risk category (score ≥ 4) with the use of the simple physician reminders (N. Engl. J. Med. 2005;352:969-77). Prospective validation showed that VTE increased proportionally with higher scores, Dr. Kibbe said. On the other hand, the model lacked sensitivity at low VTE risk, because 20% of patients with a score of 4 or less actually had VTEs.

“So, while it was simple, it only works well for the high-risk category,” she said.

• Rogers model. One of the most vigorously studied and developed RAMs is the Rogers model (J. Am. Coll. Surg. 2007;204:1211-21). It identified 15 variables (including lab values, patient characteristics, disease states, work relative-value unit, and type of operation) that were independently associated with VTE formation among 183,609 patients undergoing general, vascular, or thoracic procedures at 142 Veterans Health Administration and private hospitals. Each variable is assigned a value from 0 to 9 and added together to create a Rogers score.

Validation showed that VTE risk correlates with the Rogers score, rising from 0.11% for patients with a low score (< 7) to 1.32% for those with a high score (> 10), Dr. Kibbe said. Criticisms of the model are that it is complex, VTE incidence in the entire cohort was low at just 0.63%, the type of VTE prophylaxis used was unclear, and the model lacks prospective validation in a vascular surgery cohort.

• Caprini model. The most commonly used RAM is the 2005 Caprini model (Dis. Mon. 2005;51:70-8), which assigns a weighted score based on more than 30 VTE risk factors compiled by the authors. It has been prospectively validated in numerous studies and shown to accurately stratify 30-day VTE risk at 0.5% for patients at very low risk, 1.5% for low risk, 3% for moderate risk, and 6% for high risk.

The Caprini model, however, was not developed with the same rigor as the Rogers RAM, some of the risk factors have been shown not to be a risk for VTE, and it is complex, Dr. Kibbe observed.

• Pannucci model. The Pannucci model was created specifically to counteract the complexity of the Rogers and Caprini RAMs and incorporates only seven risk factors (personal history of VTE, current cancer, age ≥ 60 years, body mass index ≥ 40 kg/m², male sex, sepsis/septic shock/systemic inflammatory response syndrome, and family history of VTE) into a weighted index for 90-day VTE risk (Chest 2014;145:567-73). The model was developed using a statewide database and a derivation cohort made up of 20% vascular surgery patients.

Both the derivation and validation cohorts identified an 18-fold variation in VTE risk from the lowest- to highest-risk surgical population, showing that the model stratifies patients correctly. Further prospective validation is needed, Dr. Kibbe said.

• Scarborough model. Finally, in an attempt to develop a RAM specific to vascular surgery patients, Dr. John Scarborough and colleagues examined 6,035 patients undergoing open AAA repair in the NSQIP database. The 30-day VTE rate was 2.4% for the entire cohort. Eight independent perioperative risk factors were identified and used to create a nonweighted scoring system (J. Am. Coll. Surg. 2012;214:620-6).

Overall, 65% of patients had 0-1 risk factor and a VTE incidence of 1.5%, while 15% had 3 or more risk factors and a VTE incidence of 6.1%. The Scarborough model has good risk stratification, Dr. Kibbe said, but it is limited by the aforementioned criticisms regarding the NSQIP database, and it also needs prospective validation.

“We all know that proper VTE prophylaxis is very important for our patients; but we need mechanisms by which the attention given to this need for prophylaxis, which is a lot, is turned into proper implementation,” she said.

For Dr. Kibbe and her colleagues, proper implementation meant developing a RAM that was incorporated into the electronic medical record system for all surgical patients at the Jesse Brown VA Medical Center in Chicago. Clinicians were prompted to complete the RAM upon placing orders for preanesthesia testing clearance, and the clinical decision support system would provide a recommended prophylaxis regimen and easily selected electronic orders that could be signed.

A pre- and postimplementation analysis involving 400 consecutive patients revealed an 82% increase in patients with preoperative VTE prophylaxis ordered (22% vs. 40%), a 75% decrease in inappropriate cancellation of orders more than 12 hours before surgery (37% vs. 9%), and a nearly sevenfold increase in the number of patients receiving pharmacologic and mechanical prophylaxis (5% vs. 32%), she said. There was an 80% and 36% decline in DVT rates at 30 and 90 days postoperative, but event rates were too low to detect a significant difference (J. Vasc. Surg. 2010;51:648-54).

Dr. Kibbe reported having no financial disclosures.

[email protected]

CHICAGO – Implementation of preoperative venous thromboembolism prophylaxis requires a highly individualized approach and a little boost from information technology, one expert suggested.

“What may not be appreciated by some vascular surgeons is that for certain procedures we do, our patients actually have a high VTE [venous thromboembolism] risk. I know people think, ‘We use heparin, so our patients aren’t at high risk,’ but they actually are,” Dr. Melina Kibbe said at a symposium on vascular surgery sponsored by Northwestern University.

The VTE risk is 4.2% for open thoracoabdominal aortic aneurysm repair and 2.2% for thoracic endovascular aortic repair in the American College of Surgeons National Surgical Quality Improvement Program database. That may be an underestimation, however, because the NSQIP database captures only symptomatic events documented by imaging and those events occurring in the first 30 days after surgery.

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Smaller studies looking at the problem prospectively suggest the VTE risk is closer to 2%-12% after open aortic surgery and 5.3% after endovascular aortic repair, she said.

Add to that the U.S. Surgeon General’s 2008 call to action to prevent VTE and the Institute of Medicine’s stance that failure to provide VTE prophylaxis qualifies as a medical error, and it would be tempting for vascular surgeons to prescribe pharmacologic prophylaxis for all of their patients, or at least do so based on the type of procedure.

“But VTE formation is really secondary to patient-specific and procedure-related factors,” said Dr. Kibbe, a professor of vascular surgery at Northwestern University in Chicago.

She highlighted five current VTE risk assessment models (RAMs) and the potential returns when RAMs are incorporated into clinical decision support systems.

• Kucher model. One of the earlier and most straightforward RAMs is the Kucher model. It assessed eight weighted risk factors (advanced age, obesity, bed rest, hormone replacement therapy/oral contraceptives, major surgery, cancer, prior VTE, and hypercoagulability) and provided surgeons with electronic alerts regarding prophylaxis.

VTE rates dropped from 8.2% to 4.9% in the high-risk category (score ≥ 4) with the use of the simple physician reminders (N. Engl. J. Med. 2005;352:969-77). Prospective validation showed that VTE increased proportionally with higher scores, Dr. Kibbe said. On the other hand, the model lacked sensitivity at low VTE risk, because 20% of patients with a score of 4 or less actually had VTEs.

“So, while it was simple, it only works well for the high-risk category,” she said.

• Rogers model. One of the most vigorously studied and developed RAMs is the Rogers model (J. Am. Coll. Surg. 2007;204:1211-21). It identified 15 variables (including lab values, patient characteristics, disease states, work relative-value unit, and type of operation) that were independently associated with VTE formation among 183,609 patients undergoing general, vascular, or thoracic procedures at 142 Veterans Health Administration and private hospitals. Each variable is assigned a value from 0 to 9 and added together to create a Rogers score.

Validation showed that VTE risk correlates with the Rogers score, rising from 0.11% for patients with a low score (< 7) to 1.32% for those with a high score (> 10), Dr. Kibbe said. Criticisms of the model are that it is complex, VTE incidence in the entire cohort was low at just 0.63%, the type of VTE prophylaxis used was unclear, and the model lacks prospective validation in a vascular surgery cohort.

• Caprini model. The most commonly used RAM is the 2005 Caprini model (Dis. Mon. 2005;51:70-8), which assigns a weighted score based on more than 30 VTE risk factors compiled by the authors. It has been prospectively validated in numerous studies and shown to accurately stratify 30-day VTE risk at 0.5% for patients at very low risk, 1.5% for low risk, 3% for moderate risk, and 6% for high risk.

The Caprini model, however, was not developed with the same rigor as the Rogers RAM, some of the risk factors have been shown not to be a risk for VTE, and it is complex, Dr. Kibbe observed.

• Pannucci model. The Pannucci model was created specifically to counteract the complexity of the Rogers and Caprini RAMs and incorporates only seven risk factors (personal history of VTE, current cancer, age ≥ 60 years, body mass index ≥ 40 kg/m², male sex, sepsis/septic shock/systemic inflammatory response syndrome, and family history of VTE) into a weighted index for 90-day VTE risk (Chest 2014;145:567-73). The model was developed using a statewide database and a derivation cohort made up of 20% vascular surgery patients.

Both the derivation and validation cohorts identified an 18-fold variation in VTE risk from the lowest- to highest-risk surgical population, showing that the model stratifies patients correctly. Further prospective validation is needed, Dr. Kibbe said.

• Scarborough model. Finally, in an attempt to develop a RAM specific to vascular surgery patients, Dr. John Scarborough and colleagues examined 6,035 patients undergoing open AAA repair in the NSQIP database. The 30-day VTE rate was 2.4% for the entire cohort. Eight independent perioperative risk factors were identified and used to create a nonweighted scoring system (J. Am. Coll. Surg. 2012;214:620-6).

Overall, 65% of patients had 0-1 risk factor and a VTE incidence of 1.5%, while 15% had 3 or more risk factors and a VTE incidence of 6.1%. The Scarborough model has good risk stratification, Dr. Kibbe said, but it is limited by the aforementioned criticisms regarding the NSQIP database, and it also needs prospective validation.

“We all know that proper VTE prophylaxis is very important for our patients; but we need mechanisms by which the attention given to this need for prophylaxis, which is a lot, is turned into proper implementation,” she said.

For Dr. Kibbe and her colleagues, proper implementation meant developing a RAM that was incorporated into the electronic medical record system for all surgical patients at the Jesse Brown VA Medical Center in Chicago. Clinicians were prompted to complete the RAM upon placing orders for preanesthesia testing clearance, and the clinical decision support system would provide a recommended prophylaxis regimen and easily selected electronic orders that could be signed.

A pre- and postimplementation analysis involving 400 consecutive patients revealed an 82% increase in patients with preoperative VTE prophylaxis ordered (22% vs. 40%), a 75% decrease in inappropriate cancellation of orders more than 12 hours before surgery (37% vs. 9%), and a nearly sevenfold increase in the number of patients receiving pharmacologic and mechanical prophylaxis (5% vs. 32%), she said. There was an 80% and 36% decline in DVT rates at 30 and 90 days postoperative, but event rates were too low to detect a significant difference (J. Vasc. Surg. 2010;51:648-54).

Dr. Kibbe reported having no financial disclosures.

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