Role of late renal revascularization in functional renal salvage.

The duration that renal parenchyma will tolerate ischemia has continued to be debated. We have reported the cases of three patients who had undergone revascularization procedures with successful return of baseline renal function after prolonged renal artery occlusion of 14 days to 3 months. These cases highlight that aggressive revascularization can lead to successful renal salvage in selected patients. We examined the characteristics of these patients and those of others in the literature and reviewed the factors favoring recovery.

Sensor-Based Upper-Extremity Frailty Assessment for the Vascular Surgery Risk Stratification.

BACKGROUND: Available methods for determining outcomes in vascular surgery patients are often subjective or not applicable in nonambulatory patients. The purpose of the present study was to assess the association between vascular surgery outcomes and a previously validated upper-extremity function (UEF) method, which incorporates wearable motion sensors for the physical frailty assessment. MATERIALS AND METHODS: Patients (≥50 y old) undergoing vascular surgery were recruited. Participants performed the 20-s UEF test, which involved rapid elbow flexion. This technology quantifies physical frailty features including slowness, weakness, exhaustion, and flexibility, which allows grouping individuals into nonfrail, prefrail, and frail categories. Surgical outcomes included length of hospital stay, discharged disposition, and 30-d mortality, complications, readmission, and reintervention(s). Associations between outcomes and frailty were assessed using nominal logistic regression models, adjusted for age, gender, body mass index, and wound classification. RESULTS: Thirty-seven participants were recruited: eight nonfrail (age = 62.0 ± 10.6); 22 prefrail (age = 65.6 ± 11.6); and seven frail (age = 68.0 ± 8.0). Significant associations were observed between frailty and length of hospital stay (three times longer among frail participants, P = 0.03), mortality after surgery (two incidents among frail participants, P < 0.01), and adverse discharge disposition (all nonfrail patients were discharged home, whereas only 43% of frail patients discharged home, P = 0.01). CONCLUSIONS: This is the first study to validate the utility of UEF among patients undergoing any vascular surgery. Findings suggest that UEF may provide an objective and simple approach for assessing frailty to predict adverse events after vascular surgery, especially for nonambulatory patients.

The impact and outcomes of establishing an integrated interdisciplinary surgical team to care for the diabetic foot.

OBJECTIVE: This study aimed to quantify the impact of an integrated diabetic foot surgical service on outcomes and changes in surgical volume and focus. METHODS: We abstracted registry data from 48 consecutive months at a single institution, evaluating all patients with diabetic foot complications requiring surgery or vascular intervention, and compared outcomes in the 24 months before and after integrating podiatric surgery with vascular surgical limb-salvage service. RESULTS: The service performed 2923 operations; 790 (27.0%) were related to treatment of diabetic foot complications in 374 patients. Of these, 502 were classified as non-vascular diabetic foot surgery and 288 were vascular interventions. Urgent surgery was significantly reduced after team implementation (77.7% vs 48.5%, p < 0.0001; OR = 3.7, 95% CI: 2.4-5.5). The high/low amputation ratio decreased from 0.35 to 0.27 due to an increase in low-level (midfoot) amputations (8.2% vs 26.1%, p < 0.0001; OR = 4.0, 95% CI: 2.0-83.3). A 45.7% reduction in below-knee amputations was realized with a stable above-knee/below-knee amputation ratio (0.73-0.81). One-third of patients required vascular intervention. Vascular reconstructions increased 44.1% following institution of the team. Initial revascularization was endovascular in 70.6% of patients. Repeat endovascular intervention or conversion to open bypass was required in 37.1% of these patients, almost double the reintervention rate of those receiving open bypass first (18.9%). CONCLUSIONS: Interdisciplinary diabetic foot surgery teams may significantly impact surgery type, with greater focus on proactive and preventive, rather than reactive and ablative, procedures. Although endovascular limb-sparing procedures have become increasingly applicable, open bypass remains critical to success.

The natural history of duplex-detected stenosis after femoropopliteal endovascular therapy suggests questionable clinical utility of routine duplex surveillance.

OBJECTIVE: Duplex ultrasound (DU) surveillance (DUS) criteria for vein graft stenosis and thresholds for reintervention are well established. The natural history of DU-detected stenosis and the threshold criteria for reintervention in patients undergoing endovascular therapy (EVT) of the femoropopliteal system have yet to be determined. We report an analysis of routine DUS after infrainguinal EVT. METHODS: Consecutive patients undergoing EVT of the superficial femoral artery (SFA) or popliteal artery were prospectively enrolled in a DUS protocol (≤1 week after intervention, then at 3, 6, and 12 months thereafter). Peak systolic velocity (PSV) and velocity ratio (Vr) were used to categorize the treated artery: normal was PSV <200 cm/s and Vr <2, moderate stenosis was PSV = 200-300 cm/s or Vr = 2-3, and severe stenosis was PSV >300 cm/s or Vr >3. Reinterventions were generally performed for persistent or recurrent symptoms, allowing us to analyze the natural history of DU-detected lesions and to perform sensitivity and specificity analysis for DUS criteria predictive of failure. RESULTS: Ninety-four limbs (85 patients) underwent EVT for SFA-popliteal disease and were prospectively enrolled in a DUS protocol. The initial scans were normal in 61 limbs (65%), and serial DU results remained normal in 38 (62%). In 17 limbs (28%), progressive stenoses were detected during surveillance. The rate of thrombosis in this subgroup was 10%. Moderate stenoses were detected in 28 (30%) limbs at initial scans; of these, 39% resolved or stabilized, 47% progressed to severe, and occlusions developed in 14%. Five (5%) limbs harbored severe stenoses on initial scans, and 80% of lesions resolved or stabilized. Progression to occlusion occurred in one limb (20%). The last DUS showed 25 limbs harbored severe stenoses; of these, 13 (52%) were in symptomatic patients and thus required reintervention regardless of DU findings. Eleven limbs (11%) eventually occluded. Sensitivity and specificity of DUS to predict occlusion were 88% and 60%, respectively. CONCLUSIONS: DUS does not reliably predict arterial occlusion after EVT. Stenosis after EVT appears to have a different natural history than restenosis after vein graft bypass. EVT patients are more likely to have severe stenosis when they present with recurrent symptoms, in contrast to vein graft patients, who commonly have occluded grafts when they present with recurrent symptoms. The potential impact of routine DU-directed reintervention in patients after EVT is questionable. The natural history of DU-detected stenosis after femoropopliteal endovascular therapy suggests questionable clinical utility of routine DUS.

Vertebral artery aneurysms and cervical arteriovenous fistulae in patients with neurofibromatosis 1.

Vascular involvement in the setting of neurofibromatosis type 1(NF1) has been well described. However, the coexistence of NF1 with vertebral artery (VA) aneurysms and arteriovenous fistulae (AVFs) is a rare occurrence. A 60-year-old female with NF1 and other severe comorbidities presented with acute respiratory insufficiency caused by a ruptured large VA aneurysm and an associated AVF that required emergent intubation and eventual repair through endovascular techniques that resolved her symptoms. A detailed description of this case and a comprehensive review of the literature are also presented.

Delayed superficial femoral artery stent erosion and pseudoaneurysm following endovascular therapy for occlusive disease.

A 78 year-old male with multiple serious medical comorbidities was diagnosed with a pseudoaneurysm of the proximal superficial femoral artery. He had undergone successful superficial femoral artery (SFA) stenting for limb salvage four months previously and a Duplex ultrasound had confirmed adequacy of the endovascular procedure two months after its execution. This was successfully treated with placement of a covered-stent at the proximal SFA and a balloon-expandable stent at the origin of the deep femoral artery. Unfortunately the patient expired six weeks after the last endovascular intervention, likely due to procedural-unrelated causes. We postulate delayed stent erosion of a proximal atherosclerotic SFA, causing the pseudoaneurysm. This is the first report of such a case in the literature.

Vein diameter is the major predictor of fistula maturation.

OBJECTIVES: Preoperative duplex ultrasound mapping of veins and arteries has been widely advocated to maximize the creation of native arteriovenous fistula (AVF) for hemodialysis access, but reliable diameter criteria have not been established. We sought to determine patient and anatomic variables predictive of fistula maturation in patients receiving their initial permanent hemodialysis access. METHODS: All patients undergoing dialysis access creation from January 2003 to June 2007 were retrospectively reviewed. We analyzed fistula type and functional maturation rates (Society for Vascular Surgery [SVS] reporting standards) based on patient characteristics and findings on physical examination, preoperative vein mapping studies, or venography. Maturation and patency rates were determined by Kaplan Meier analysis. The following factors were analyzed: age, race, gender, body-mass index (BMI), fistula site, preoperative duplex vein diameter, diabetes, hyperlipidemia, HTN, prior central catheter placement, HIV, and history of IV drug abuse. RESULTS: From January 2003 to June 2007, 298 vascular access procedures were performed. One hundred ninety-five (65%) were initial hemodialysis access procedures, among which a native AVF was created in 185 (95%); 158 patients with posterior radiocephalic AVF (PRCAVF, n = 24), wrist radiocephalic AVF (WRCAVF, n = 72), or brachiocephalic AVF (BCAVF, n = 62) had adequate follow-up and were included in the analysis. PRCAVF, WRCAVF, and BCAVF had 54%, 66%, and 81% maturation rates, respectively. Both the type of fistula type (P = .032) and vein size (P = .002) significantly affected maturation by univariate analysis. In contrast, by multivariate logistic regression analysis, vein diameter was the sole independent predictor of fistula functional maturation (P = .002). CONCLUSION: In this series of 158 patients undergoing initial hemodialysis access creation, native AVF creation was performed in 95%. In contrast to previous reports, age, gender, diabetes, and BMI had no significant effect on functional maturation. By multivariate logistic regression analysis, vein diameter was the sole independent predictor of functional fistula maturation.

Aortoiliac aneurysm repair in kidney transplant recipients.

A potential problem during endovascular aortic aneurysm repair (EVAR) or open repair in renal allograft patients is ischemia of the transplanted kidney. In this study, kidney transplant patients who underwent aortic aneurysm repair in our institution were added to similar cases extracted from the literature to represent the basis of this work. Comparisons between patients treated with open surgery versus EVAR were performed in terms of renal function. In the EVAR group, most aneurysms were infrarenal, and 84% were treated with modular bifurcated devices. Protective kidney allograft perfusion measures were not used. The pre- and postoperative Cr was 1.69 and 1.73 mg/dL, respectively (P = .412). All EVAR patients had good outcomes. Complications included 8 endoleaks and 1 limb ischemia case. Three patients died from aortic repair-unrelated reasons. In the open group, the pre-and postoperative Cr was 1.45 and 1.37 mg/dL, respectively (P = .055). Most cases were infrarenal and mostly treated by aortobiiliac bypasses. In 16%, no adjuvant allograft perfusion was provided. In the rest, temporary axillofemoral bypasses were used most often. Most outcomes were favorable (57%). Reported procedural-related complications included arterial embolism, wound infection, and pneumonia. Deaths were reported in 5 occasions (none allograft failure dependent). No differences in Cr between EVAR and open techniques (P = .13) were seen. Aneurysm repair in kidney transplant recipients is associated with excellent renal preservation. Adverse outcomes were all allograft failure independent in both groups. EVAR without special allograft protection measures seems to be equally effective as open surgery with or without adjuvant kidney transplant perfusion.

Aortic stent-graft explantation in a kidney transplant recipient.

AAA repair in renal transplant recipients has generated a variety of methods of managing the allograft. Endovascular techniques have been successfully employed in this patient population. Due to inherent limitations of present endovascular methods, occasional stent-graft excision must be performed. We present a case of aortic stent-graft excision in a renal transplant recipient using a pump-oxygenator to maintain allograft perfusion.

Superficial femoral artery thrombosis as a cause for distal embolism in primary antiphospholipid syndrome.

Antiphospholipid syndrome is a diagnosis with the clinical manifestations of thromboses in the presence of an antiphospholipid antibody. A 25-year-old man with a history of deep venous thrombosis, pulmonary emboli, and myocardial infarction, and receiving long-term anticoagulation with warfarin, all due to primary antiphospholipid syndrome, presented with blue toe syndrome from a primary superficial femoral artery thrombus. He was anticoagulated with fondaparinux in addition to dipyridamole and aspirin perioperatively. The area of thrombus was resected and reconstructed using a cephalic vein interposition graft. This report reviews antiphospholipid syndrome and identifies potential questions and problems relating to a rare clinical presentation.

Comparison of the effects of open and endovascular aortic aneurysm repair on long-term renal function using chronic kidney disease staging based on glomerular filtration rate.

OBJECTIVE: It has been suggested that endovascular aneurysm repair (EVAR) in concert with serial contrast-enhanced computed tomography (CT) surveillance adversely impacts renal function. Our primary objectives were to assess serial renal function in patients undergoing EVAR and open repair (OR) and to evaluate the relative effects of method of repair on renal function. METHODS: A thorough retrospective chart review was performed on 223 consecutive patients (103 EVAR, 120 OR) who underwent abdominal aortic aneurysm (AAA) repair. Demographics, pertinent risk factors, CT scan number, morbidity, and mortality were recorded in a database. Baseline, 30- and 90-day, and most recent glomerular filtration rate (GFR) were calculated. Mean GFR changes and renal function decline (using Chronic Kidney Disease [CKD] staging and Kaplan-Meier plot) were determined. EVAR and OR patients were compared. CKD prevalence (>or=stage 3, National Kidney Foundation) was determined before repair and in longitudinal follow-up. Observed-expected (OE) ratios for CKD were calculated for EVAR and OR patients by comparing observed CKD prevalence with the expected, age-adjusted prevalence. RESULTS: The only baseline difference between EVAR and OR cohorts was female gender (4% vs 12%, P = .029). Thirty-day GFR was significantly reduced in OR patients (P = .047), but it recovered and there were no differences in mean GFR at a mean follow-up of 23.2 months. However, 18% to 39% of patients in the EVAR and OR groups developed significant renal function decline over time depending on its definition. OE ratios for CKD prevalence were greater in AAA patients at baseline (OE 1.28-3.23, depending upon age group). During follow-up, the prevalence and severity of CKD increased regardless of method of repair (OE 1.8-9.0). Deterioration of renal function was independently associated with age >70 years in all patients (RR 2.92) and performance of EVAR compared with OR (RR 3.5) during long-term follow-up. CONCLUSIONS: Compared with EVAR, OR was associated with a significant but transient fall in GFR at 30 days. Renal function decline after AAA repair was common, regardless of method, especially in patients >70 years of age. However, the renal function decline was significantly greater by Kaplan-Meier analysis in EVAR than OR patients during long-term follow-up. More aggressive strategies to monitor and preserve renal function after AAA repair are warranted.

Measure what matters: institutional outcome data are superior to the use of surrogate markers to define "center of excellence" for abdominal aortic aneurysm repair.

Outcome analysis is increasingly being used to develop health-care policy and direct patient referral. For example, the Leapfrog Group health-care quality initiative has proposed "evidence-based hospital" referral criteria for specific procedures including elective abdominal aortic aneurysm repair (AAA-R). These criteria include an annual hospital AAA operative volume exceeding 50 cases and provision of intensive care unit (ICU) care by board-certified intensivists. Outcomes after AAA-R are reportedly influenced by presentation (intact vs. ruptured), operative approach (endovascular vs. open, transperitoneal vs. retroperitoneal), surgeon subspecialty, case volume (hospital and surgeon), and provision of postoperative care by an intensivist. The purpose of this study was to compare our single-center results with those of high-volume centers to assess the validity of the concept that surrogate markers, such as case volume or intensivist involvement, can be used to estimate procedural outcome. A retrospective review was performed of AAA-Rs at one low-volume academic medical center from January 1994 to March 2005. Demographic data, aneurysm diameter and location, operative indications, and repair approach were documented. Postoperative complications, mortality rates, and hospital and ICU length of stay (LOS) were noted and compared to established benchmarks. During the study period, 270 patients underwent AAA-R (annual mean = 27 hospital cases and 13.4 cases/attending vascular surgeon). ICU care was provided by a dedicated vascular surgery service without routine intensivist involvement. Open, elective, infrarenal AAA-R was performed in 161 patients (60%), with a 2.5% hospital mortality rate (30-day, 3.1%). Thirty-three (12%) patients underwent elective endovascular aneurysm repair (EVAR), with no mortality. Both ICU (3.7 vs. 1.4 days, p = 0.03) and hospital (9.2 vs. 2.8 days, p = 0.002) LOS were significantly reduced after EVAR compared to open repair. Hospital LOS was significantly lower after open retroperitoneal repair compared to transperitoneal repair (6.1 vs. 10.3 days, p = 0.001). Thirty-five patients (13%) underwent ruptured AAA-R, with only 34.3% mortality (in-hospital and 30-day). Forty-one patients (15%) underwent repair of complex aortic aneurysms, with 14.1% mortality. There are increasing societal and economic pressures to direct patient referrals to "centers of excellence" for specific surgical procedures. Although our institution meets neither of the Leapfrog Group's proposed criteria, our mortality and LOS for both intact and ruptured infrarenal AAA-R are equivalent or superior to published benchmarks for high-volume hospitals. Individual institutional outcome results such as these suggest that patient referral and care should be based upon actual, carefully verified outcome data rather than utilization of surrogate markers such as case volume and subspecialist involvement in postoperative care.

Contemporary outcomes after superficial femoral artery angioplasty and stenting: the influence of TASC classification and runoff score.

OBJECTIVE: A recent randomized trial suggested nitinol self-expanding stents (SES) were associated with reduced restenosis rates compared with simple percutaneous transluminal angioplasty (PTA). We evaluated our results with superficial femoral artery (SFA) SES to determine whether TransAtlantic InterSociety Consensus (TASC) classification, indication for intervention, patient risk factors, or Society of Vascular Surgery (SVS) runoff score correlated with patency and clinical outcome, and to evaluate if bare nitinol stents or expanded polytetrafluoroethylene (ePTFE) covered stent placement adversely impacts the tibial artery runoff. METHODS: A total of 109 consecutive SFA stenting procedures (95 patients) at two university-affiliated hospitals from 2003 to 2006 were identified. Medical records, angiographic, and noninvasive studies were reviewed in detail. Patient demographics and risk factors were recorded. Procedural angiograms were classified according to TASC Criteria (I-2000 and II-2007 versions) and SVS runoff scores were determined in every patient; primary, primary-assisted, secondary patency, and limb salvage rates were calculated. Cox proportional hazard model was used to determine if indication, TASC classification, runoff score, and comorbidities affected outcome. RESULTS: Seventy-one patients (65%) underwent SES for claudication and 38 patients (35%) for critical limb ischemia (CLI). Average treatment length was 15.7 cm, average runoff score was 4.6. Overall 36-month primary, primary-assisted, and secondary rates were 52%, 64%, and 59%, respectively. Limb salvage was 75% in CLI patients. No limbs were lost following interventions in claudicants (mean follow-up 16 months). In 24 patients with stent occlusion, 15 underwent endovascular revision, only five (33%) ultimately remained patent (15.8 months after reintervention). In contrast, all nine reinterventions for in-stent stenosis remained patent (17.8 months). Of 24 patients who underwent 37 endovascular revisions for either occlusion or stenosis, eight (35%) had worsening of their runoff score (4.1 to 6.4). By Cox proportional hazards analysis, hypertension (hazard ratio [HR] 0.35), TASC D lesions (HR 5.5), and runoff score > 5 (HR 2.6) significantly affected primary patency. CONCLUSIONS: Self-expanding stents produce acceptable outcomes for treatment of SFA disease. Poorer patency rates are associated with TASC D lesions and poor initial runoff score; HTN was associated with improved patency rates. Stent occlusion and in-stent stenosis were not entirely benign; one-third of patients had deterioration of their tibial artery runoff. Future studies of SFA interventions need to stratify TASC classification and runoff score. Further evaluation of the long-term effects of SFA stenting on tibial runoff is needed.

The limitations of magnetic resonance angiography in the diagnosis of renal artery stenosis: comparative analysis with conventional arteriography.

PURPOSE: Gadolinium-enhanced magnetic resonance angiography (MRA) is commonly used as a screening modality for the detection of renal artery stenosis. However, evidence supporting its utility in clinical practice is lacking; few rigorous studies have compared MRA with contrast arteriography (CA). After making anecdotal clinical observations that MRA sometimes overestimated the degree of renal artery stenosis, we decided to determine the interobserver variability, sensitivity, specificity, and diagnostic accuracy of MRA compared with CA. METHODS: From September 1999 to April 2003, we evaluated 68 renal arteries in 34 patients with clinically suspected renal artery stenosis using both MRA and CA. All studies were independently reviewed by four blinded observers. Renal arteries were categorized by MRA as normal, <50%, and >50% stenosis/occlusion. The sensitivity, specificity, and accuracy of MRA detection of renal artery stenosis were compared to CA as the gold standard. Interobserver variability (kappa) was also calculated. RESULTS: MRA demonstrated 87% sensitivity, 69% specificity, 85% accuracy, 95% negative predictive value, and 51% positive predictive value for the diagnosis of renal artery stenosis. Interobserver agreement was moderate for MRA (kappa = 0.53) and good for CA (kappa = 0.76). In 21 arteries (31%), MRA was falsely positive. CONCLUSIONS: In patients with a high clinical suspicion of renal artery stenosis, MRA is 87% sensitive in the detection of >50% stenosis. However, MRA is relatively nonspecific compared with CA and results in significant overestimation of renal artery stenosis in nearly one third of patients. To reduce unnecessary CA, clinicians should consider supplemental studies.