Alexander D. Shepard

Complement activation by synthetic vascular prostheses

Morphologic evaluation of synthetic grafts (both seeded and unseeded) harvested within 2 weeks of implantation has revealed heavy infiltration with polymorphonuclear leukocytes (PMNs). Since complement-activated PMNs are known to damage endothelial cells, we hypothesized that complement activation might prove a barrier to optimal endothelial cell seeding of prosthetic grafts. To determine whether synthetic vascular prostheses activate complement and whether the type of graft material influences the degree of activation, we assayed the plasma of 10 healthy donors for complement activity following incubation with short segments of knitted Dacron and polytetrafluoroethylene (PTFE) graft material. C5a generation was measured by radioimmunoassay and granulocyte aggregometry. Standard hemolytic assays were used to determine depletion of functional classical pathway (CH50 and C4) alternative pathway (APH50) activity. Results indicated substantial complement activation by Dacron and virtually none by PTFE. Activation by Dacron appeared to occur via both complement pathways. Such complement reactivity may have important implications for the performance of prosthetic materials as small-caliber vascular grafts, whether seeded with endothelial cells or not.

Results of lower extremity amputations in patients with end-stage renal disease

PURPOSEnThe purpose of this study was to determine the impact of end-stage renal disease (ESRD) on the outcome of patients undergoing lower extremity (LE) amputation.nnnMETHODSnHospital charts and vascular surgery registry data were reviewed for all patients who underwent LE amputation over a consecutive 56-month period. The results of 84 patients with ESRD (137 amputations) were compared with 375 patients (442 amputations) without ESRD.nnnRESULTSnHospital mortality rate was significantly greater in patients with ESRD than patients without ESRD, 24% versus 7% (p = 0.001). Patients with ESRD undergoing minor amputations had mortality rates three times greater than patients without ESRD undergoing major LE amputations. In patients with ESRD requiring bilateral or unilateral above-knee amputation hospital mortality rates were 43% and 38%, respectively. In addition, patients with ESRD were seven times more likely to undergo bilateral amputation than patients without ESRD over a mean follow-up period of 17 months. No kidney transplant patients died after amputation.nnnCONCLUSIONnESRD has a profound negative impact on morbidity, mortality, and survival rates after LE amputation. Attempts at prevention of amputation with aggressive foot care and patient education in this high-risk group should be the focus of therapy.

Groin lymphatic complications after arterial reconstruction

PURPOSEnThe purpose of this study was to better define the associated risks and optimal management of groin lymphatic complications (GLC) after femoral artery reconstructive operations.nnnMETHODSnRetrospective review of a vascular surgery registry for the last 15 years identified 2679 arterial operations requiring a groin incision. Forty-one GLC were recognized, 28 lymphocutaneous fistulas (LF) and 13 lymphoceles.nnnRESULTSnThe incidence of GLC was 1.5% per patient or 1.2% per incision. The highest incidence of GLC was in patients having an aortobifemoral bypass for aneurysmal disease in a previously operated groin (8.1% per patient) and in those undergoing an isolated femoral procedure in a previously operated groin (5.3%). The lowest frequency of GLC was after femoropopliteal/tibial bypasses (0.5%). Twenty-nine patients (71%) were treated without operation with bedrest, intravenous antibiotics, and aggressive local wound care. Operative therapy with wound reexploration attempted identification and control of the leak site, and meticulous wound closure was used in 12 patients (29%). Lymph fistulas in patients undergoing reoperation (10/28) resolved sooner than in patients treated without operation (18/28) (9 +/- 3 days vs 24 +/- 3 days). Infectious wound complications with one resultant graft infection developed in five of 18 patients with LF who did not undergo reoperation. There were no wound or graft infections in the patients in the LF group treated with operation. Operative exploration of lymphoceles did not reduce hospital stay or infectious wound complications. Repetitive lymphocele aspiration did not affect rapidity of resolution or increase the infectious complications.nnnCONCLUSIONnGLC remain a troublesome complication of femoral arterial reconstruction. Early reoperation should be performed once a LF is diagnosed. Treatment for lymphoceles should be individualized, with neither operative nor nonoperative management showing clear superiority.

Ultrasound characteristics of recurrent carotid disease: Hypothesis explaining the low incidence of symptomatic recurrence*

The true incidence of recurrent disease after carotid endarterectomy (CENDX) is unknown, but noninvasive hemodynamic testing shows a paradox between the incidence of hemodynamically significant recurrent stenosis (RS) and the presence of symptomatic disease. We have shown that real-time B-mode ultrasound imaging can demonstrate the gross pathology of the arterial wall and plaque and their surface characteristics. Therefore we reviewed the clinical data and B-mode studies performed 6 months to 15 years after 276 carotid endarterectomies. Preoperative and perioperative risk factors and associated symptoms on follow-up were stored on computer. The patients were divided into three groups by the anatomy of their B-mode study. The majority of the studies were normal (203 [73.5%]), 42 (15.2%) showed mild disease, and 34 (12.3%) demonstrated significant RS. The RS group had a statistically significant increase in incidence of known lipid abnormalities (p less than 0.05), associated peripheral vascular disease, previous myocardial infarctions, and ulcerated plaque on the original carotid endarterectomy (p less than 0.01). The site of RS appeared related to the time of detection by B-mode ultrasound imaging. Internal carotid RS developed late (greater than 4 years), as did RS of the bifurcation. By contrast, stenosis at the common carotid level developed earlier. These findings suggest different pathogenic mechanisms--for the former, redevelopment of atherosclerosis; for the latter, accentuation of preexisting atherosclerosis perhaps by hemodynamic factors. Finally, in the 26 vessels with RS without occlusion, there was an 8% incidence of plaque ulcer or hemorrhage vs. a 62% incidence in 79 primary atherosclerotic plaques previously studied by both B-mode and pathologic examination. The low incidence of plaque characteristics associated with symptomatic disease may account for the low incidence of symptomatic disease associated with RS.

Surgical complications of transaxillary arteriography: A case-control study

PURPOSEnThe purpose of this study was to review the complications of transaxillary arteriography (TRAX), determine clinical factors associated with their occurrence, and define optimal treatment methods.nnnMETHODSnA retrospective review of 842 consecutive TRAX studies performed in a large, urban, tertiary care, academic medical center was undertaken. Patients with complications were compared with a concurrent randomized control group without complications with the use of a multivariate analysis model. Results of operative therapy for nerve injury were compared with those of nonoperative therapy.nnnRESULTSnNineteen (2.3%) complications were identified including 14 nerve injuries, four expanding hematomas/pseudoaneurysms without neurologic deficit, and one puncture site thrombosis. Several statistically significant or suggestive findings associated with the occurrence of complications were identified: female sex (odds ratio [OR] = 4.7), systolic blood pressure > or = 150 mm Hg at the conclusion of TRAX (OR = 9.5), periprocedural systemic heparin anticoagulation (OR = 7.9), concomitant use of intraarterial thrombolysis or percutaneous angioplasty (OR = 12.0), and duration of procedure > or = 90 minutes (OR = 4.0). Patients who underwent prompt exploration (< or = 4 hours from symptom onset) for nerve injuries were more likely to have complete resolution of their neurologic deficits (five of six patients) than those who were observed or underwent delayed operation (three of eight patients) (OR = 8.3).nnnCONCLUSIONSnAggressive treatment of post-TRAX hypertension, limitation of TRAX duration, delay of postprocedure anticoagulation, and use of alternative sites for arterial puncture in female patients or patients undergoing catheter-based intervention may reduce the incidence of TRAX-related complications. In patients who have neurologic deficits prompt surgical exploration of the puncture site with decompression of the involved nerve(s) may reduce the incidence of prolonged deficits.

Noninvasive venous testing in the diagnosis of pulmonary embolism: The impact on decisionmaking

PURPOSEnTo characterize the use and utility of lower extremity noninvasive venous testing (NIVT) in the diagnosis of pulmonary embolism (PE).nnnMETHODSnThe study is a retrospective case series of consecutive patients in whom PE was suspected who were referred to a large, urban tertiary care center for NIVT. The main outcome measures of the study were the rate of positive results of NIVT, the amount of new information provided by NIVT, and the frequency of management changes that were attributable to NIVT.nnnRESULTSnForty-one of 450 patients (9%) had deep venous thrombosis (DVT) by NIVT. The prevalence of DVT by NIVT among patients not evaluated by ventilation/perfusion (V/Q) scanning was 8%. The prevalence of DVT by NIVT among patients with a high-probability V/Q scan result before NIVT was 39%, but no management decisions in this group were based on a positive NIVT result and only two decisions were based on negative NIVT results. The prevalence of DVT according to NIVT among patients who had a negative diagnostic (low, or very low probability, or normal) result of V/Q scan before NIVT was 2%. The overall frequency of management changes attributed to NIVT was only 2.5%. In the remaining 97% of patients, management was determined by the result of V/Q scanning or of subsequent pulmonary arteriography.nnnCONCLUSIONSnIn patients in whom PE is suspected, results of NIVT are usually negative for acute DVT. Management decisions are almost always based on V/Q scan or results of pulmonary arteriography and not on NIVT. The utility of NIVT to identify DVT in these patients appears limited, and a more selective approach to its application for the diagnosis of PE should be considered.

Critical Limb Ischemia in Patients with End-Stage Renal Disease: Do Long-Term Results Justify An Aggressive Surgical Approach?

End-stage renal disease (ESRD) patients probably represent the most difficult group of patients vascular surgeons are called upon to treat for critical limb ischemia. Advanced lower extremity arterial occlusive disease and frequent comorbidities make infrainguinal arterial bypass grafting (IABG) in this population both technically and medically challenging. Results of IABG are far inferior to those in non-ESRD patients. The greatest limitation to limb salvage appears to be progressive tissue necrosis and infection despite a patent bypass graft, a problem nearly unique to ESRD. Clinical predictors of outcome for IABG in this population have not been well established. The site and extent of tissue loss, the presence of associated infection, and the degree of pedal level occlusive disease have been identified as potentially important predictors. Improving outcome for ESRD patients with critical limb ischemia requires the establishment of firm guidelines for IABG to avoid futile and risky attempts at bypass i...

PC180. Superficial Femoral Artery Balloon Angioplasty Stent Implantation-Outcome Stratified by Type of Follow-up Evaluation: Arterial Duplex Imaging versus Ankle-Brachial Index Only

Results: Clinical case 2 describes a 48-year-old woman with a history of Takayasus arteritis, prior proximal descending thoracic aorta to infrarenal abdominal aortic bypass and bypass to the left renal artery for mid-aortic syndrome, and atrophic right kidney presented with severe hypertension, fluid overload, and hyperkalemia, and a creatinine of 5.8 mg/dL requiring urgent dialysis. She was anuric and dialysis dependent. Magnetic resonance angiography revealed occlusion of the left renal artery bypass which originated from the aortic bypass graft and collateral filling of the left kidney with differential areas of perfusion (Fig 2). She underwent redo aortic graft to left renal artery bypass 18 days after her initial presentation. Upon discharge, she was no longer dialysis dependent and her creatinine has normalized. Conclusions: Two patients presenting with dialysis dependent acute renal failure underwent delayed renal artery revascularization, greater than 14 days from their presentation. Complete renal recovery with return to baseline renal function was observed in these patients. In select patients, delayed renal artery revascularization (>48 hours of warm ischemic time) is controversial, but can be associated with complete renal recovery and freedom from dialysis.

Benefit of Arterial Duplex Ultrasound Stent Imaging After Superficial Femoral Artery Stent Implantation: Impact of Surveillance Method on Postprocedural Outcome

Objective: In-stent stenosis is a frequent complication of superficial femoral artery (SFA) endovascular intervention and can lead to stent occlusion or symptom recurrence. Arterial duplex ultrasound stent imaging (ADSI) can be used in the surveillance for recurrent stenosis; however, its uniform application is controversial. In this study, we aimed to determine, in patients undergoing SFA stent implantation (SI), whether surveillance with ADSI yielded a better outcome than in those with only anklebrachial index (ABI) follow-up. Methods: We performed a retrospective analysis of all patients undergoing SFA SI for occlusive disease at a tertiary care referral center between 2009 and 2016. The patients were divided into those with ADSI (ADSI group) and those with ABI follow-up only (ABI group). Life-table analysis comparing stent patency, major adverse limb event (MALE), limb salvage, and mortality between groups was performed. Results: There were 248 patients with SFA SI included, 160 in the ADSI group and 88 in the ABI group. Groups were homogeneous regarding clinical indication (claudication/critical limb ischemia, ADSI 39%/61% vs ABI 38%/62%; P 1⁄4 .982) and TransAtlantic Inter-Society Consensus classification (A/B/C/D for ADSI 17%/45%/16%/22% and ABI 21%/43%/16%/20%; P 1⁄4 .874). Primary patency (PP) was similar between groups at 12, 36, and 56 months (ADSI, 65%/43%/32%; ABI, 69%/34%/34%; P 1⁄4 .770), whereas ADSI patients showed an improved assisted PP (84%/68%/54%) vs ABI (76%/38%/38%; P 1⁄4 .008) and secondary patency (Fig 1). There was a greater freedom from MALE in the ADSI group (91%/76%/64%) vs the ABI group (79%/46%/46%; P < .001) at 12, 36, and 56 months of followup. ADSI patients were more likely to undergo an endovascular procedure as their initial post-SFA SI intervention (P 1⁄4 .001), whereas ABI patients were more likely to undergo an amputation (P < .001; Fig 2). Conclusions: In SFA SI, patients with ADSI follow-up demonstrate an advantage in assisted PP and secondary patency and are more likely to undergo an endovascular reintervention. These factors likely effected a

Contrast-induced nephropathy after peripheral vascular intervention: Long-term renal outcome and risk factors for progressive renal dysfunction

Objective Contrast‐induced nephropathy (CIN) is a frequently used quality outcome marker after peripheral vascular interventions (PVIs). Whereas the factors associated with CIN development have been well documented, the long‐term renal effects of CIN after PVI are unknown. This study was undertaken to investigate the long‐term (1‐year) renal consequences of CIN after PVI and to identify factors associated with renal function deterioration at 1‐year follow‐up. Methods From 2008 to 2015, patients who had PVI at our institution (who were part of a statewide Vascular Interventions Collaborative) were queried for those who developed CIN. CIN was defined by the Collaborative as an increase in serum creatinine concentration of at least 0.5 mg/dL within 30 days after intervention. Preprocedural dialysis patients or patients without postprocedural creatinine values were excluded. Preprocedural, postprocedural, and 1‐year serum creatinine values were abstracted and used to estimate glomerular filtration rate (GFR). &Dgr;GFR was defined as preprocedural GFR minus 1‐year GFR. Univariate and multivariate analyses for &Dgr;GFR were performed to determine factors associated with renal deterioration at 1 year. Results From 2008 to 2015, there were 1323 PVIs performed; 881 patients met the inclusion criteria. Of these, 57 (6.5%) developed CIN; 47% were male, and 51% had baseline chronic kidney disease. CIN resolved by discharge in 30 patients (53%). Using multivariate linear regression, male sex (P = .027) and congestive heart failure (P = .048) were associated with 1‐year GFR decline. Periprocedural variables related to 1‐year GFR decline included percentage increase in 30‐day postprocedural creatinine concentration (P = .025), whereas CIN resolution by discharge (mean, 13.1 days) was protective for renal function at 1 year (P = .02). A post hoc analysis was performed with 50 PVI patients (randomly selected) who did not develop CIN, comparing their late renal function with that of the CIN group stratified by the periprocedural 30‐day variables. Patients with CIN resolution at discharge had similar 1‐year renal outcomes to non‐CIN patients, whereas the CIN‐persistent (at discharge) patients had greater renal deterioration at 1 year compared with non‐CIN patients (P = .016). Conclusions Male sex and congestive heart failure are risk factors for further renal function decline in patients developing CIN after PVI. The magnitude and duration of increase in creatinine concentration (CIN persistence at discharge) correlated with late progressive renal dysfunction in CIN patients, suggesting that early‐resolving CIN is relatively benign.