Peter L. Faries

Ex vivo human carotid artery bifurcation stenting: Correlation of lesion characteristics with embolic potential

PURPOSE To develop an ex vivo human carotid artery stenting model that can be used for the quantitative analysis of risk for embolization associated with balloon angioplasty and stenting and to correlate this risk with lesion characteristics to define lesions suitable for balloon angioplasty and stenting. METHODS Specimens of carotid plaque (n = 24) were obtained circumferentially intact from patients undergoing standard carotid endarterectomy. Carotid lesions were prospectively characterized on the basis of angiographic and duplex findings before endarterectomy and clinical findings. Specimens were encased in a polytetrafluoroethylene wrap and mounted in a flow chamber that allowed access for endovascular procedures and observations. Balloon angioplasty and stenting were performed under fluoroscopic guidance with either a Palmaz stent or a Wallstent endoprosthesis. Ex vivo angiograms were obtained before and after intervention. Effluent from each specimen was filtered for released embolic particles, which were microscopically examined, counted, and correlated with various plaque characteristics by means of multivariate analysis. RESULTS Balloon angioplasty and stenting produced embolic particles that consisted of atherosclerotic debris, organized thrombus, and calcified material. The number of embolic particles detected after balloon angioplasty and stenting was not related to preoperative symptoms, sex, plaque ulceration or calcification, or artery size. However, echolucent plaques generated a higher number of particles compared with echogenic plaques (p < 0.01). In addition, increased lesion stenosis also significantly correlated with the total number of particles produced by balloon angioplasty and stenting (r = 0.55). Multivariate analysis revealed that these two characteristics were independent risk factors. CONCLUSIONS Echolucent plaques and plaques with stenosis > or = 90% produced a higher number of embolic particles and therefore may be less suitable for balloon angioplasty and stenting. This ex vivo model can be used to identify high-risk lesions for balloon angioplasty and stenting and can aid in the evaluation of new devices being considered for carotid balloon angioplasty and stenting.

Simulation improves resident performance in catheter-based intervention: results of a randomized, controlled study.

Objectives:Surgical simulation has been shown to enhance the training of general surgery residents. Since catheter-based techniques have become an important part of the vascular surgeons armamentarium, we explored whether simulation might impact the acquisition of catheter skills by surgical residents. Methods:Twenty general surgery residents received didactic training in the techniques of catheter intervention. Residents were then randomized with 10 receiving additional training with the Procedicus, computer-based, haptic simulator. All 20 residents then participated in 2 consecutive mentored catheter-based interventions for lower extremity occlusive disease in an OR/angiography suite. Resident performance was graded by attending surgeons blinded to the residents training status, using 18 procedural steps as well as a global rating scale. Results:There were no differences between the 2 resident groups with regard to demographics or scores on a visuospatial test administered at study outset. Overall, residents exposed to simulation scored higher than controls during the first angio/OR intervention: procedural steps (simulation/control) (50 ± 6 vs. 33 ± 9, P = 0.0015); global rating scale (30 ± 7 vs. 19 ± 5, P = 0.0052). The advantage provided by simulator training persisted with the second intervention (53 ± 6 vs. 36 ± 7, P = 0.0006); global rating scale (33 ± 6 vs. 21 ± 6, P = 0.0015). Moreover, simulation training, particularly for the second intervention, led to enhancement in almost all of the individual measures of performance. Conclusion:Simulation is a valid tool for instructing surgical residents and fellows in basic endovascular techniques and should be incorporated into surgical training programs. Moreover, simulators may also benefit the large number of vascular surgeons who seek retraining in catheter-based intervention.

Management of endoleak after endovascular aneurysm repair: cuffs, coils, and conversion

OBJECTIVE The effectiveness of endovascular treatment of abdominal aortic aneurysm (AAA) may be limited by persistent perfusion of the aneurysm sac (endoleak). Endoleak that results in persistent systemic pressurization of the aneurysm or in continued AAA expansion is believed to require treatment to prevent rupture. This report describes the results of three techniques used to treat endoleak. METHODS Endovascular repair of AAA was performed in 597 patients between January 1996 and September 2002. Seventy-three endoleaks that required treatment developed in 70 patients (11.7%). These involved the graft attachment site (type I) or the graft junction site (type III) or originated from collateral side-branch vessels (type II) and were associated with an increase in aneurysm size. Endoleak type was confirmed at angiography in all cases. Average time between the initial endovascular procedure and endoleak treatment was 14.5 +/- 5.7 months. The techniques used for endoleak treatment were deployment of an endovascular extension graft or cuff (n = 44), coil embolization (n = 24,) and conversion to conventional open repair (n = 5). Configurations of endovascular grafts in which endoleak developed were bifurcated (n = 44), aortouniiliac (n = 15), and aortoaortic-tube (n = 11). Mean follow-up after endoleak treatment was 24.5 +/- 12.2 months (range, 1-60 months). RESULTS Endovascular extension grafts or cuffs were used to treat 41 attachment site endoleaks and 3 graft junction endoleaks, with overall technical success rate of 97%. Embolic coils were used to treat 16 retrograde side-branch endoleaks and 8 attachment site endoleaks, with overall technical success rate of 87%. Conversion to open surgery was performed in 4 patients with attachment site endoleaks and 1 patient with a graft junction site endoleak, and was successful in all cases. After endoleak treatment, aneurysm size decreased (>5 mm) in 38% of patients, stabilized in 58% of patients, and increased (>5 mm) in 4% of patients. Major morbidity occurred in 7.0%, with no perioperative deaths. CONCLUSIONS Endovascular extension grafts, coil embolization, and conversion to open surgery each may be used to effectively repair endoleak. Selection of the treatment method used is determined by the anatomic characteristics of the endoleak and the patients ability to tolerate conventional repair. Conversion to open repair was uniformly successful. Deployment of an extension cuff was successful when complete closure of the endoleak was achieved. Embolic coils were effective for retrograde endoleaks and provided stabilization of AAA size in selected patients with attachment site endoleaks in limited follow-up.

Shifting Paradigms in the Treatment of Lower Extremity Vascular Disease: A Report of 1000 Percutaneous Interventions

Objectives:Catheter-based revascularization has emerged as an alternative to surgical bypass for lower extremity vascular disease and is a frequently used tool in the armamentarium of the vascular surgeon. In this study we report contemporary outcomes of 1000 percutaneous infra-inguinal interventions performed by a single vascular surgery division. Methods:We evaluated a prospectively maintained database of 1000 consecutive percutaneous infra-inguinal interventions between 2001 and 2006 performed for claudication (46.3%) or limb-threatening ischemia (52.7%; rest pain in 27.7% and tissue loss in 72.3%). Treatments included angioplasty with or without stenting, laser angioplasty, and atherectomy of the femoral, popliteal, and tibial vessels. Results:Mean age was 71.4 years and 57.3% were male; comorbidities included hypertension (84%), coronary artery disease (51%), diabetes (58%), tobacco use (52%), and chronic renal insufficiency (39%). Overall 30-day mortality was 0.5%. Two-year primary and secondary patencies and rate of amputation were 62.4%, 79.3%, and 0.5%, respectively, for patients with claudication. Two-year primary and secondary patencies and limb salvage rates were 37.4%, 55.4%, and 79.3% for patients with limb-threatening ischemia. By multivariable Cox PH modeling, limb-threat as procedural indication (P < 0.0001), diabetes (P = 0.003), hypercholesterolemia (P = 0.001), coronary artery disease (P = 0.047), and Transatlantic Inter-Society Consensus D lesion complexity (P = 0.050) were independent predictors of recurrent disease. For patients that developed recurrent disease, 7.5% required no further intervention, 60.3% underwent successful percutaneous reintervention, 11.7% underwent bypass and 20.5% underwent amputation. Patency rates were identical for the initial procedure and subsequent reinterventions (P = 0.97). Conclusion:Percutaneous therapy for peripheral vascular disease is associated with minimal mortality and can achieve 2-year secondary patency rates of nearly 80% in patients with claudication. Although patency is diminished in patients with limb-threat, limb-salvage rates remain reasonable at close to 80% at 2 years. Percutaneous infra-inguinal revascularization carries a low risk of morbidity and mortality, and should be considered first-line therapy in patients with chronic lower extremity ischemia.

Reduced primary patency rate in diabetic patients after percutaneous intervention results from more frequent presentation with limb-threatening ischemia

OBJECTIVE Although patients with diabetes are at increased risk of amputation from peripheral vascular disease, excellent limb-salvage rates have been achieved with aggressive surgical revascularization. It is less clear whether patients with diabetes will fare as well as nondiabetics after undergoing percutaneous lower extremity revascularization, a modality which is becoming increasingly utilized for this disease process. This study aimed to assess differential outcomes in between diabetics and nondiabetics in lower extremity percutaneous interventions. METHODS We retrospectively studied 291 patients with respect to patient variables, complications, and outcomes for percutaneous interventions performed for peripheral occlusive disease between 2002 and 2005. Tibial vessel run-off was assessed by angiography. Patency (assessed arterial duplex) was expressed by Kaplan-Meier method and log-rank analysis. Mean follow-up was 11.6 months (range 1 to 56 months). RESULTS A total of 385 interventions for peripheral occlusive disease with claudication (52.2%), rest pain (16.4%), or tissue loss (31.4%) were analyzed, including 336 primary interventions and 49 reinterventions (mean patient age 73.9 years, 50.8% male). Comorbidities included diabetes mellitus (57.2%), chronic renal insufficiency (18.4%), hemodialysis (3.8%), hypertension (81.9%), hypercholesterolemia (57%), coronary artery disease (58%), tobacco use (63.2%). Diabetics were significantly more likely to be female (55.3% vs 40.8%), and suffer from CRI (23.5% vs 12.0%), a history of myocardial infarction (36.5% vs 18.0%), and <three-vessel tibial outflow (83.5% vs 71.8%), compared with nondiabetics, although all other comorbidities and lesion characteristics were equivalent between these groups. Overall primary patency (+/- SE) at 6, 12, and 18 months was 85 +/- 2%, 63 +/- 3% and 56 +/- 4%, respectively. Patients with diabetes suffered reduced primary patency at 1 year compared with nondiabetics. For nondiabetics, primary patency was 88 +/- 2%, 71 +/- 4%, and 58 +/- 4% at 6, 12, and 18 months, while for diabetics it was 82 +/- 2%, 53 +/- 4%, and 49 +/- 4%, respectively (P = .05). Overall secondary patency at 6, 12, and 18 months was 88 +/- 2%, 76 +/- 3%, and 69 +/- 3%, and did not vary by diabetes status. One-year limb salvage rate was 88.3% for patients with limb-threatening ischemia, which was also similar between diabetics and nondiabetics. While univariate analysis revealed that female gender, <three-vessel tibial outflow, and a history of tobacco use were all predictive of reduced primary patency (P < .05), none of these factors significantly impacted secondary patency or limb-salvage rate. Furthermore, only limb-threatening ischemia remained a significant predictor of outcome on multivariate analysis, suggesting that the poorer primary patency in diabetics is related primarily to their propensity to present with limb-threatening disease compared with nondiabetics. CONCLUSION Patients with diabetes demonstrate reduced primary patency rates after percutaneous treatment of lower extremity occlusive disease, most likely due to their advanced stage of disease at presentation. However, despite a higher reintervention rate, diabetics and others with risk factors predictive of reduced primary patency can attain equivalent short-term secondary patency and limb-salvage rates. Therefore, these patient characteristics should not be considered contraindications to endovascular therapy.

Effect of gender on long-term survival after abdominal aortic aneurysm repair based on results from the Medicare national database

OBJECTIVES Historically, women have higher procedurally related mortality rates than men for abdominal aortic aneurysm (AAA) repair. Although endovascular aneurysm repair (EVAR) has improved these rates for men and women, effects of gender on long-term survival with different types of AAA repair, such as EVAR vs open aneurysm repair (OAR), need further investigation. To address this issue, we analyzed survival in matched cohorts who received EVAR or OAR for both elective (eAAA) and ruptured AAA (rAAA). METHODS Using the Medicare Beneficiary Database (1995-2006), we compiled a cohort of patients who underwent OAR or EVAR for eAAA (n = 322,892) or rAAA (n = 48,865). Men and women were matched by propensity scores, accounting for baseline demographics, comorbid conditions, treating institution, and surgeon experience. Frailty models were used to compare long-term survival of the matched groups. RESULTS Perioperative mortality for eAAAs was significantly lower among EVAR vs OAR recipients for both men (1.84% vs 4.80%) and women (3.19% vs 6.37%, P < .0001). One difference, however, was that the survival benefit of EVAR was sustained for the 6 years of follow-up in women but disappeared in 2 years in men. Similarly, the survival benefit of men vs women after elective EVAR disappeared after 1.5 to 2 years. For rAAAs, 30-day mortality was significantly lower for EVAR recipients compared with OAR recipients, for both men (33.43% vs 43.70% P < .0001) and women (41.01% vs 48.28%, P = .0201). Six-year survival was significantly higher for men who received EVAR vs those who received OAR (P = .001). However, the survival benefit for women who received EVAR compared with OAR disappeared in 6 months. Survival was also substantially higher for men than women after emergent EVAR (P = .0007). CONCLUSIONS Gender disparity is evident from long-term outcomes after AAA repair. In the case for rAAA, where the long-term outcome for women was significantly worse than for men, the less invasive EVAR treatment did not appear to benefit women to the same extent that it did for men. Although the long-term outcome after open repair for elective AAA was also worse for women, EVAR benefit for women was sustained longer than for men. These associations require further study to isolate specific risk factors that would be potential targets for improving AAA management.

Analysis of gender-related differences in lower extremity peripheral arterial disease

INTRODUCTION Gender-related differences continue to challenge the management of lower extremity (LE) peripheral arterial disease (PAD) in women. We analyzed the time-trends in hospital care of such differences. METHODS Data for patients with PAD from New York, New Jersey, and Florida state hospital inpatient discharge databases (1998-2007) were analyzed using univariate and multivariate regression analyses. RESULTS The 2.4 million PAD-related inpatient discharge records analyzed showed a slight decrease of inpatient procedures for both genders. Compared with men, women had 18% to 27% fewer PAD and 33% to 49% fewer vascular procedural hospitalizations (P < .0001). They were persistently more likely than men to be admitted emergently (56% vs 51% in 1998 and 57% vs 53% in 2007) and discharged to a nursing home. During the study period, the amputation rate declined by 36% in women and 21% in men with PAD, and similarly, open procedures decreased by 36% and 30%. Endovascular procedures, however, increased by 150% in women and 144% in men. Procedural mortality was 4.95% vs 4.37% for men (P < .0001). Female mortality rates were persistently higher after amputations (9.89% vs 8.90%, P < .0001), open (5.49% vs 4.00%, P < .0001), and endovascular procedures (2.87% vs 2.10%, P < .0001). Time trends showed improved mortality for men and women, with a stable difference between the two. CONCLUSION The analysis of representative state administrative databases of inpatient care records demonstrated improvements in mortality and amputation rates over time. However, a gender-related disparity in PAD outcomes remains that merits further investigation.

Polytetrafluoroethylene bypasses to infrapopliteal arteries without cuffs or patches: A better option than amputation in patients without autologous vein

PURPOSE This study was undertaken to evaluate our results of polytetrafluoroethylene (PTFE) tibial and peroneal artery bypasses done for limb salvage. METHODS Within a group of patients undergoing infrainguinal limb salvage bypasses at our institution between January 1986 and May 1995, 63 patients faced an immediate amputation, had no autologous vein on duplex examination and operative exploration, and had only a tibial or peroneal artery as an outflow vessel for bypass. Most of these patients (82%) had two or more prior ipsilateral infrainguinal bypasses. These 63 patients underwent 66 PTFE bypasses to a tibial or peroneal artery without a distal anastomotic vein cuff or an adjunctive arteriovenous fistula. Our results were then compared with those reported from infrapopliteal (crural) bypasses performed with alternate autologous vein sources or PTFE in conjunction with various recommended adjuncts. RESULTS The 3- and 5-year cumulative primary graft patency rates for our PTFE infrapopliteal bypasses were 39%+/-7% and 28%+/-9%, respectively. Secondary graft patency rates were 55%+/-8% and 43%+/-10% at 3 and 5 years, respectively. Limb salvage rates were 71%+/-7% at 3 years and 66%+/-8% at 5 years. Two-year actuarial patient survival rate was only 67%+/-7%. CONCLUSIONS These results indicate that a PTFE bypass to an infrapopliteal artery remains a worthwhile option in patients without usable autologous vein. The secondary patency and limb salvage rates were acceptable in this setting and were not significantly different from the best results reported with prosthetic tibial/peroneal bypasses with distal vein cuffs or patches (74% at 1 year; 58% at 3 years), arteriovenous fistulas (71% at 1 year) or composite arm vein grafts (39% and 29% at 3 and 5 years, respectively).

Chronic intraaneurysmal pressure measurement: An experimental method for evaluating the effectiveness of endovascular aortic aneurysm exclusion

PURPOSE To evaluate and compare the intraaneurysmal pressure (IAP) after exclusion using two different endovascular grafts. METHODS Eight mongrel dogs had a 3 x 3 cm polytetrafluoroethylene (PTFE) aneurysm sewn as an interposition graft of the infrarenal aorta. A pressure transducer implanted into the aneurysm wall permitted continuous electronic IAP monitoring. Four aneurysms were excluded with a transluminally placed endovascular graft made of a PTFE graft and two Palmaz stents (PTFE-EG), three were excluded with a tantalum-Dacron endovascular graft (TD-EG), and one was surgically treated with a standard PTFE graft (PTFE-Surg). The dogs were observed for 18 to 50 days (mean, 37.5 days) and were evaluated after surgery with duplex and spiral computed tomographic scans. RESULTS All grafts successfully excluded the aneurysms without perigraft channels or leaks as documented by arteriogram and duplex and computed tomographic scans. The mean IAPs after repair with all PTFE-EGs were significantly lower (p < 0.001) than the mean systemic pressures. In addition, the mean IAP reduction was significantly greater (p < 0.005) in the PTFE-EG group than in the TD-EG group. CONCLUSIONS Aneurysm exclusion with PTFE-EG significantly lowered IAP, did so significantly better than the TD-EG, and approached the IAP reduction obtained by standard repair. Such pressure reduction is necessary for effective protection against aneurysm rupture.

Open Versus Endovascular Stent Graft Repair of Abdominal Aortic Aneurysms: A Meta-Analysis of Randomized Trials

OBJECTIVES This study sought to evaluate the short-, intermediate-, and longer-term outcomes after endovascular versus open repair of abdominal aortic aneurysms (AAA), including both AAA-related and all-cause mortality. BACKGROUND Endovascular stent graft placement for AAA has gained broad acceptance as an alternative to open surgical repair due to a lower perioperative morbidity and mortality. The intermediate- and long-term all-cause and aneurysm-related mortality vary among studies. Thus, we sought to perform a meta-analysis of open versus endovascular repair for treating AAA. METHODS Electronic databases were queried for identification of prospective, randomized trials of open surgery versus endovascular stent graft repair of AAA. A total of 10 published papers reporting on 6 studies at different follow-up intervals were identified; they involved 2,899 patients with AAA repair procedures, of whom, 1,470 underwent endovascular stent graft AAA exclusion and 1,429 were treated by open AAA repair. RESULTS At 30 days, the pooled relative risk of all-cause mortality was lower in the endovascular group (relative risk [RR]: 0.35, 95% confidence interval [CI]: 0.19 to 0.64) than in the open surgery group. At intermediate follow-up, the all-cause mortality had a nonsignificant difference (RR: 0.78, 95% CI: 0.57 to 1.08), the AAA-related mortality was significantly lower (RR: 0.46, 95% CI: 0.28 to 0.74) and reintervention rates were higher (RR: 1.48, 95% CI: 1.06 to 2.08) in the endovascular group than in the open surgery group. At long-term follow-up, there was no significant difference in all-cause mortality (RR: 0.99, 95% CI: 0.85 to 1.15) or AAA-related mortality (RR: 1.58, 95% CI: 0.20 to 12.74), whereas the significant difference in the rate of reinterventions persisted (RR: 2.54, 95% CI: 1.58 to 4.08). CONCLUSIONS In patients randomized to open or endovascular AAA repair, all-cause perioperative mortality, as well as AAA-related mortality at short- and intermediate-term follow-up are lower in patients undergoing endovascular stent graft placement. This was associated with greater reintervention in the endovascular group noted at intermediate follow-up. Long-term survival appears to converge between the 2 groups.