The natural history of chronic limb-threatening ischemia after technical failure of endovascular intervention.

OBJECTIVES: The treatment for chronic limb-threatening ischemia (CLTI) has changed dramatically in the last few decades with a shift toward an endovascular-first approach and aggressive revascularization to achieve limb salvage. As the size of the CLTI population and intervention rates increase, patients will continue to experience technical failure (TF). Here, we describe the natural history of patients after TF of endovascular intervention for CLTI. METHODS: We conducted a retrospective cohort study of patients with CLTI who attempted endovascular intervention or bypass at our multidisciplinary limb salvage center from 2013 to 2019. Patient characteristics were collected according to the Society for Vascular Surgery's reporting standards. Primary outcomes included survival, limb salvage, wound healing, and revascularization patency. Product-limit Kaplan-Meier estimated survival functions for these outcomes, and between-group comparisons were made using Mantel-Cox log-rank nonparametric tests. RESULTS: We identified 242 limbs from 220 unique patients who underwent primary bypass (n = 30) or attempted endovascular intervention (n = 212) at our limb salvage center. Endovascular intervention was a TF in 31 (14.6%) limbs. After TF, 13 limbs underwent secondary bypass and 18 limbs were managed medically. Patients who experienced TF tended to be older (P < .001), male (P = .003), current tobacco users (P = .014), have longer lesions (P = .001), and have chronic total occlusions of target arteries (P < .001) as compared with those who experienced technical success. Furthermore, the TF group had worse limb salvage (P = .047) and slower wound healing (P = .028), but their survival was not different. Survival, limb salvage, and wound healing were not different in patients who received secondary bypass or medical management after TF. The secondary bypass group was older (P = .012) and had a lower prevalence of tibial disease (P = .049) than the primary bypass group and trended toward decreased survival, limb salvage, and wound healing (P = .059, P = .083, and P = .051, respectively). CONCLUSIONS: Increased age, male sex, current tobacco use, longer arterial lesions, and occluded target arteries are associated with TF of endovascular intervention. Limb salvage and wound healing are relatively poor after TF of endovascular intervention, but survival appears comparable with patients who experience technical success. Secondary bypass may not always rescue patients after TF, though our sample size limits statistical power. Interestingly, patients who received a secondary bypass after TF trended toward decreased survival, limb salvage, and wound healing compared with primary bypass.

Vessel-by-vessel analysis of lower extremity 18F-NaF PET/CT imaging quantifies diabetes- and chronic kidney disease-induced active microcalcification in patients with peripheral arterial disease.

BACKGROUND: Positron emission tomography (PET)/computed tomography (CT) imaging with fluorine-18 (18F)-sodium fluoride (NaF) provides assessment of active vascular microcalcification, but its utility for evaluating diabetes mellitus (DM)- and chronic kidney disease (CKD)-induced atherosclerosis in peripheral arterial disease (PAD) has not been comprehensively evaluated. This study sought to use 18F-NaF PET/CT to quantify and compare active microcalcification on an artery-by-artery basis in healthy subjects, PAD patients with or without DM, and PAD patients with or without CKD. Additionally, we evaluated the contributions of DM, CKD, statin use and established CT-detectable calcium to 18F-NaF uptake for each lower extremity artery. METHODS: PAD patients (n = 48) and healthy controls (n = 8) underwent lower extremity 18F-NaF PET/CT imaging. Fused PET/CT images guided segmentation of arteries of interest (i.e., femoral-popliteal, anterior tibial, tibioperoneal trunk, posterior tibial, and peroneal) and quantification of 18F-NaF uptake. 18F-NaF uptake was assessed for each artery and compared between subject groups. Additionally, established calcium burden was quantified for each artery using CT calcium mass score. Univariate and multivariate analyses were performed to evaluate DM, CKD, statin use, and CT calcium mass as predictors of 18F-NaF uptake in PAD. RESULTS: PAD patients with DM or CKD demonstrated significantly higher active microcalcification (i.e., 18F-NaF uptake) for all arteries when compared to PAD patients without DM or CKD. Univariate and multivariate analyses revealed that concomitant DM or CKD was associated with increased microcalcification for all arteries of interest and this increased disease risk remained significant after adjusting for patient age, sex, and body mass index. Statin use was only associated with decreased microcalcification for the femoral-popliteal artery in multivariate analyses. Established CT-detectable calcium was not significantly associated with 18F-NaF uptake for 4 out of 5 arteries of interest. CONCLUSIONS: 18F-NaF PET/CT imaging quantifies vessel-specific active microcalcification in PAD that is increased in multiple lower extremity arteries by DM and CKD and decreased in the femoral-popliteal artery by statin use. 18F-NaF PET imaging is complementary to and largely independent of established CT-detectable arterial calcification. 18F-NaF PET/CT imaging may provide an approach for non-invasively quantifying vessel-specific responses to emerging anti-atherogenic therapies or CKD treatment in patients with PAD.

Extra-Anatomic Bypass and Excision is Superior to Graft Salvage Attempts with Antibiotic Beads to Treat Vascular Graft Infections in the Groin.

BACKGROUND: This study aimed to determine if conventional extra-anatomic bypass and graft removal versus aggressive attempts at graft preservation have better survival and limb salvage in patients with localized groin wound infections of vascular grafts. METHODS: We conducted a retrospective review of 53 consecutive patients with vascular graft infections presenting in the groin. Treatment groups consisted of group 1 (extra-anatomic bypass and graft excision, n = 22) and group 2 (initial graft preservation attempts with utilization of antibiotic beads, n = 31). In group 2, patients underwent serial debridement and placement of antibiotic beads until culture-negative wounds were achieved. Significantly more patients underwent muscle flap coverage in group 2 (27/31) compared with group 1 (7/22; P < 0.001). Data collected included demographics, comorbidities, intraoperative details, and outcomes, including patency, limb salvage, mortality, and number of procedures. Continuous variables were examined with Student's t-test, and dichotomous variables were examined with chi-squared test. Linear and logistic regressions were used to analyze factors associated with outcomes, in addition to Kaplan-Meier analysis with log rank for actuarial analysis. RESULTS: Both groups were similar with respect to demographics. The overall Kaplan-Meier 1- and 3-year survival rates were 66.2% and 34.1%, with no statistically significant difference between groups. The Kaplan-Meier 1- and 3-year limb salvage rates were 68.8% and 36.6% for group 1 vs. 58.5% and 38.7% for group 2 (P = not significant [NS]). The 1- and 3-year primary patency rates were 71% and 71% in traditional group 1 vs. 72% and 56% in group 2 (P = NS). One-year and 3-year secondary patency rates in traditional group 1 were 83% and 71% vs. 85% and 61% in group 2 (P = NS). Patients in group 1 underwent fewer total procedures when compared with group 2 (2.3 ± 0.2 vs. 5.1 ± 0.7, P = 0.03). The late reinfection rate was significantly less in group 1 (4.5%) compared with group 2 (26%; P = 0.04). Freedom from reinfection at 1 and 3 years were 94% and 94% in traditional group 1 vs. 74% and 62% in group 2 (P = 0.03). Multivariable analysis showed a higher incidence of amputation in patients who suffered reinfection (n = 13, P = 0.049). There was a higher mortality in patients with septic shock (n = 10, P = 0.007) and reinfection (n = 13, P = 0.036). Reinfection was associated with the highest mortality (P = 0.03). CONCLUSIONS: Conventional graft excision with extra-anatomic bypass resulted in similar mortality when compared with aggressive attempts at graft preservation and trended toward improved limb salvage and patency. However, attempts at graft preservation with antibiotic beads resulted in a significantly higher reinfection rate and greater number of procedures, and therefore, this approach should be used very selectively.

A prebifurcated axillobifemoral polytetrafluoroethylene graft simplifies carotid to carotid to subclavian bypass.

The use of thoracic endovascular aortic repair for thoracic aortic disease will necessitate cervical debranching in cases involving the proximal arch. We have presented the case of a 57-year-old athletic woman who had developed a type A dissection that extended to the bilateral iliac arteries. After hemiarch repair, she underwent staged cervical debranching with carotid-carotid-subclavian bypass using a prebifurcated axillobifemoral graft and subsequent thoracic endovascular aortic repair. We have detailed her successful clinical course and described the benefits of using a prebifurcated graft for cervical debranching in hybrid repairs of aortic arch pathology.

Long-term outcomes of transposed femoral vein arteriovenous fistula for abandoned upper extremity dialysis access.

BACKGROUND: The number and longevity of patients with end-stage renal disease requiring dialysis access have continued to increase, leading to challenging situations, including exhausted upper extremity access and severe central venous stenosis. This has led to an increase in the use of alternative access sites, including the lower extremities. The transposed femoral vein arteriovenous fistula for dialysis access is a previously described alternative, although limited data are available on its long-term patency. METHODS: Patients treated with a transposed femoral vein fistula were retrospectively reviewed. A transposed femoral vein fistula was created by harvesting the femoral vein and transposing it to the distal superficial femoral artery at the level of the adductor canal. The demographic information, perioperative characteristics, complications, and long-term outcomes were recorded and analyzed. RESULTS: A total of 21 patients had undergone transposed femoral vein fistula for dialysis access after an average of 5.3 ± 2.8 failed dialysis access procedures and a duration of 6.1 ± 4.9 years from the initiation of dialysis. The average age at the procedure was 53.5 ± 12.8 years. Ten patients (47.6%) had a history of diabetes mellitus and nine (42.9%) had a history of coronary artery disease. Technical success was achieved in 100% of cases, and 16 patients (76.2%) were discharged with anticoagulation therapy. The primary patency at 1, 3, and 5 years was 93%, 74%, and 74%, respectively. The secondary patency at 1, 3, and 5 years was 100%, 89%, and 89%, respectively. Two patients had compartment syndrome requiring fasciotomy, and six patients experienced wound complications. CONCLUSIONS: Transposed femoral vein fistula for dialysis access is a viable alternative for patients with an exhausted upper extremity access, with good long-term patency.

Trends and perioperative outcomes of patients with human immunodeficiency virus (HIV) undergoing lower extremity revascularization.

The development of highly active antiretroviral therapy (HAART) has significantly improved the life expectancy of patients with human immunodeficiency virus (HIV), but has led to the rise of chronic conditions including peripheral artery disease (PAD). However, trends and outcomes among patients with HIV undergoing lower extremity revascularization are poorly characterized. The aim of this study was to investigate the trends and perioperative outcomes of lower extremity revascularization among patients with HIV and PAD in a national database. The National Inpatient Sample (NIS) was reviewed between 2003 and 2014. All hospital admissions with a diagnosis of PAD undergoing lower extremity revascularization were stratified based on HIV status. Outcomes were assessed using propensity score matching and multivariable regression. Among all patients undergoing lower extremity revascularization for PAD, there was a significant increase in the proportion of patients with HIV from 0.21% in 2003 to 0.52% in 2014 (p < 0.01). Patients with HIV were more likely to be younger, male, and have fewer comorbidities, including coronary artery disease and diabetes, at the time of intervention compared to patients without HIV. With propensity score matching and multivariable regression, HIV status was associated with increased total hospital costs, but not length of stay, major amputation, or mortality. Patients with HIV with PAD who undergo revascularization are younger with fewer comorbidities, but have increased hospital costs compared to those without HIV. Lower extremity revascularization for PAD is safe for patients with HIV without increased risk of in-hospital major amputation or mortality, and continues to increase each year.

SPECT/CT Imaging: A Noninvasive Approach for Evaluating Serial Changes in Angiosome Foot Perfusion in Critical Limb Ischemia.

Objective: To investigate the feasibility of serial radiotracer-based imaging as a noninvasive approach for quantifying volumetric changes in microvascular perfusion within angiosomes of the foot following lower extremity revascularization in the setting of critical limb ischemia (CLI). Approach: A CLI patient with a nonhealing foot ulcer underwent single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of the feet before and after balloon angioplasty of the superficial femoral artery (SFA) and popliteal artery. SPECT/CT imaging was used to evaluate serial changes in angiosome perfusion, which was compared to quantitative changes in peripheral vascular anatomy and hemodynamics, as assessed by standard clinical tools that included digital subtraction angiography (DSA), ankle-brachial index (ABI), and toe-brachial index (TBI). Results: Following revascularization, upstream quantitative improvements in stenosis of the SFA (pre: 35.4% to post: 11.9%) and popliteal artery (pre: 59.1% to post: 21.7%) shown by DSA were associated with downstream angiosome-dependent improvements in SPECT microvascular foot perfusion that ranged from 2% to 16%. ABI measurement was not possible due to extensive arterial calcification, while TBI values decreased from 0.26 to 0.16 following revascularization. Innovation: This is the first study to demonstrate the feasibility of assessing noninvasive volumetric changes in angiosome foot perfusion in response to lower extremity revascularization in a patient with CLI by utilizing radiotracer-based imaging. Conclusion: SPECT/CT imaging allows for quantification of serial perfusion changes within angiosomes containing nonhealing ulcers and provides physiological assessment that is complementary to conventional anatomical (DSA) and hemodynamic (ABI/TBI) measures in the evaluation of lower extremity revascularization.

Approaches to the Salvage of Axillary Bilateral Femoral Bypass in Patients with Claudication due to Demand Ischemia.

The axillary bilateral femoral bypass is often utilized as an alternative to in-line aortic reconstruction in patients with multiple medical comorbidities, who would be unable to tolerate open abdominal surgery with an aortic clamp, or patients with mycotic aneurysms, or infected grafts. Idealized fluid mechanics suggest that there would be equal flow in an axillary bilateral femoral bypass when compared to in-line reconstruction. However, in a non-idealized state, friction results in kinetic energy loss and decreased volume flow to the lower extremities in the longer, smaller diameter graft. Although older or less active people may tolerate the lower volume flow of a long segment extra-anatomic bypass, there is growing evidence that a subset of patients will be symptomatic from reduced flow volumes. Here we present 3 patients in whom symptomatic relief was achieved with the addition of a contralateral axillary femoral bypass and ligation of the previous femorofemoral component.

Intravascular Ultrasound in Venous Thoracic Outlet Syndrome.

BACKGROUND: Venous thoracic outlet syndrome (vTOS) is a rare disease with no defined guidelines regarding treatment. Patients with first rib resection with anterior scalenectomy (FRRS) often have residual subclavian vein stenosis. The aim of this study was to evaluate the use of intravascular ultrasound (IVUS) in the treatment of vTOS patients who have been surgically decompressed with FRRS. METHODS: Patients treated with venography after FRRS for vTOS during 2015-2017 were retrospectively reviewed. Patients were included if they received a venogram with IVUS after FRRS. The axillosubclavian vein at the site of the thoracic outlet was imaged using single-plane venography and IVUS. A greater than 50% diameter stenosis on venography or 50% cross-sectional area reduction on IVUS was considered significant and treated with balloon venoplasty. RESULTS: During the 2-year period, 14 patients underwent 24 upper extremity venograms performed after surgical decompression for vTOS, 18 of which included IVUS. Of the 18 cases with IVUS, 5 (27.8%) stenoses >50% were detected by IVUS, which were not apparent on venography, leading to intervention. IVUS detected a greater degree of stenosis than venography. Seven patients required repeat venograms. Overall, IVUS detected significant venous stenosis in 94.4% of patients compared with 66.7% of patients with venography after FRRS for vTOS. CONCLUSIONS: These results suggest that IVUS detected greater levels of stenosis than venography, leading to more interventions. Just as IVUS being ideal for identifying occult iliac venous lesions, it may have a similar role in identifying venous lesions not evident on single-plane venography for postsurgical decompression in vTOS patients. Further studies may show this technique to increase the number of stenoses identified and improve long-term symptom relief.

Abdominal Aortic Aneurysm: Evolving Controversies and Uncertainties.

Abdominal aortic aneurysm (AAA) is defined as a permanent dilatation of the abdominal aorta that exceeds 3 cm. Most AAAs arise in the portion of abdominal aorta distal to the renal arteries and are defined as infrarenal. Most AAAs are totally asymptomatic until catastrophic rupture. The strongest predictor of AAA rupture is the diameter. Surgery is indicated to prevent rupture when the risk of rupture exceeds the risk of surgery. In this review, we aim to analyze this disease comprehensively, starting from an epidemiological perspective, exploring etiology and pathophysiology, and concluding with surgical controversies. We will pursue these goals by addressing eight specific questions regarding AAA: (1) Is the incidence of AAA increasing? (2) Are ultrasound screening programs for AAA effective? (3) What causes AAA: Genes versus environment? (4) Animal models: Are they really relevant? (5) What pathophysiology leads to AAA? (6) Indications for AAA surgery: Are surgeons over-eager to operate? (7) Elective AAA repair: Open or endovascular? (8) Emergency AAA repair: Open or endovascular?

Guidelines for hospital privileges in vascular surgery and endovascular interventions: Recommendations of the Society for Vascular Surgery.

The Hospital Privileges Practice Guideline Writing Group of the Society for Vascular Surgery is making the following five recommendations concerning guidelines for hospital privileges for vascular surgery and endovascular therapy. Advanced endovascular procedures are currently entrenched in the everyday practice of specialized vascular interventionalists, including vascular surgeons, but open vascular surgery remains uniquely essential to the specialty. First, we endorse the Residency Review Committee for Surgery recommendations regarding open and endovascular cases during vascular residency and fellowship training. Second, applicants for new hospital privileges wishing to perform vascular surgery should have completed an Accreditation Council for Graduate Medical Education-accredited vascular surgery residency or fellowship or American Osteopathic Association-accredited training program before 2020 and should obtain American Board of Surgery certification in vascular surgery or American Osteopathic Association certification within 7 years of completion of their training. Third, we recommend that applicants for renewal of hospital privileges in vascular surgery include physicians who are board certified in vascular surgery, general surgery, or cardiothoracic surgery. These physicians with an established practice in vascular surgery should participate in Maintenance of Certification programs as established by the American Board of Surgery and maintain their respective board certification. Fourth, we provide recommendations concerning guidelines for endovascular procedures for vascular surgeons and other vascular interventionalists who are applying for new or renewed hospital privileges. All physicians performing open or endovascular procedures should track outcomes using nationally validated registries, ideally by the Vascular Quality Initiative. Fifth, we endorse the Intersocietal Accreditation Commission recommendations for noninvasive vascular laboratory interpretations and examinations to become a Registered Physician in Vascular Interpretation, which is included in the requirements for board eligibility in vascular surgery, but recommend that only physicians with demonstrated clinical experience in the diagnosis and management of vascular disease be allowed to interpret these studies.

Covered Stent Grafts for Acquired Arterial Venous Fistulas: A Case Series.

BACKGROUND: Stent grafts have become the preferred method for treating abdominal aortic aneurysms (AAAs) but also have utility in treating other vasculopathies. In 2005, peripheral stent grafts were approved for treating superficial femoral artery occlusive disease. This report describes our experience using covered stent grafts to treat acquired arterial venous fistulae (aAVF). METHODS: We reviewed the records of patients treated for aAVF with covered stent grafts. Eleven patients had 12 limbs treated with a stent graft. The data collected included presenting symptoms, mechanism of injury, vessel location, stent graft used for therapy, and patency. RESULTS: Eleven patients underwent successful treatment of 12 aAVF with a peripheral stent grafts. The average age was 55.6 (18-87), and there were 4 women and 7 men. The mechanisms of injuries were heart catheterization in 5 patients, penetrating trauma in 3 patients, and orthopedic injury in 3 patients. Five of the patients had concurrent pseudoaneurysms. Self-expanding expanded polytetrafluoroethelene (ePTFE) stent grafts were used in 8 patients, and balloon-expandable ePTFE stent grafts were used in 3 patients. Primary patency at 2 years is 100%, with all patients having significant relief of symptoms. CONCLUSIONS: Peripheral stent grafts are a useful tool for treating aAVF, with excellent patency. They provide a valuable minimally invasive approach to this disease.

Trends and outcomes in endovascular and open surgical treatment of visceral aneurysms.

OBJECTIVE: Visceral artery aneurysms (VAAs) are rare but often repaired because of dire consequences of rupture. This is a population-based evaluation of chronologic trends in management, risk factors, and outcomes of endovascular and open therapy. METHODS: The 2003 to 2013 Agency for Healthcare Research and Quality (AHRQ) National Inpatient Sample (NIS) database was reviewed. Cases with primary diagnosis of VAA and undergoing endovascular or open repair were identified. Patients with renal artery or abdominal or thoracoabdominal aortic disease were excluded. Case numbers of respective techniques were charted over time. Baseline characteristics and in-hospital outcomes were compared for endovascular and open groups using χ2 test, Fisher exact test, or t-test. Predictors of mortality and complications were evaluated with multivariate logistic regression. RESULTS: There were 9260 interventions for VAAs from 2003 to 2013, including 5166 endovascular and 4094 open. Endovascular repairs increased from 5.3 to 24.7 per 10 million U.S. population (P < .001), surpassing open repairs in 2008, which decreased from 14.3 to 9.2 per 10 million (P < .001). Endovascular patients were more likely to have been treated at urban teaching hospitals (77.1% vs 61.8%; P < .0001); to have higher proportions of renal failure (7.6% vs 4.9%; P = .02), liver disease (11.3% vs 6.6%; P < .001), alcohol abuse (13.1% vs 3.6%; P < .001), chronic blood loss anemia (4.5% vs 1.6%; P < .001), metastatic cancer (2.7% vs 0.8%; P = .003), solid tumor without metastases (3.6% vs 2.0%; P < .037), and weight loss (9.8% vs 5.2%; P < .001); and less likely to have had elective admission (28.9% vs 59.8%; P < .0001). In-hospital mortality (4.1% vs 4.5%; P = .618) and overall complication rates (37.8% vs 38.8%; P = .688) were similar between groups; however, pulmonary complications were decreased for endovascular patients (10.6% vs 19.7%; P < .001). Endovascular patients had shorter hospital stays (6.5 vs 8.7 days; P < .001). Multivariate adjustment for mortality predictors, including coagulopathy (odds ratio [OR], 4.34; confidence interval [CI], 2.56-7.35; P < .001), liver disease (OR, 2.25; CI, 1.25-4.07; P = .01), fluid and electrolyte disorders (OR, 2.84; CI, 1.73-4.66; P < .001), and solid tumor without metastases (OR, 2.81; CI, 1.10-7.18; P = .03), showed that open treatment was associated with increased mortality (OR, 1.70; CI, 1.03-2.81; P = .04). Analysis of overall complications revealed that open treatment was again associated with increased complications (OR, 1.78; CI, 1.43-2.21; P < .001). CONCLUSIONS: Endovascular VAA repairs are increasing. Despite patients' having worse comorbidities and more nonelective admissions, endovascular therapy appears to be associated with decreased mortality and complications and shorter hospital stays.

The LargPAD Trial: Phase IIA evaluation of l-arginine infusion in patients with peripheral arterial disease.

OBJECTIVE: Endothelial function is improved by l-arginine (l-arg) supplementation in preclinical and clinical studies of mildly diseased vasculature; however, endothelial function and responsiveness to l-arg in severely diseased arteries is not known. Our objective was to evaluate the acute effects of catheter-directed l-arg delivery in patients with chronic lower extremity ischemia secondary to peripheral arterial disease. METHODS: The study enrolled 22 patients (45% male) with peripheral arterial disease (mean age, 62 years) requiring lower extremity angiography. Endothelium-dependent relaxation of patent but atherosclerotic superficial femoral arteries was measured using a combination of intravascular ultrasound (IVUS) imaging and a Doppler FloWire (Volcano Corporation, Rancho Cordova, Calif) during the infusion of incremental acetylcholine (10-6 to 10-4 molar concentration) doses. Patients received 50 mg (n = 3), 100 mg (n = 10), or 500 mg (n = 9) l-arg intra-arterially, followed by repeat endothelium-dependent relaxation measurement (limb volumetric flow). IVUS-derived virtual histology of the culprit vessel was also obtained. Endothelium-independent relaxation was measured using a nitroglycerin infusion. Levels of nitrogen oxides and arginine metabolites were measured by chemiluminescence and mass spectrometry, respectively. RESULTS: Patients tolerated limb l-arg infusion well. Serum arginine and ornithine levels increased by 43.6% ± 13.0% and 23.2% ± 10.3%, respectively (P < .005), and serum nitrogen oxides increased by 85% (P < .0001) after l-arg infusion. Average vessel area increased by 6.8% ± 1.3% with l-arg infusion (acetylcholine 10-4; P < .0001). Limb volumetric flow increased in all patients and was greater with l-arg supplementation by 130.9 ± 17.6, 136.9 ± 18.6, and 172.1 ± 24.8 mL/min, respectively, for each cohort. Maximal effects were seen with l-arg at 100 mg (32.8%). Arterial smooth muscle responsiveness to nitroglycerin was intact in all vessels (endothelium-independent relaxation, 137% ± 28% volume flow increase). IVUS-derived virtual histology indicated plaque volume was 14 ± 1.3 mm3/cm, and plaque stratification revealed a predominantly fibrous morphology (46.4%; necrotic core, 28.4%; calcium, 17.4%; fibrolipid, 6.6%). Plaque morphology did not correlate with l-arg responsiveness. CONCLUSIONS: Despite extensive atherosclerosis, endothelial function in diseased lower extremity human arteries can be enhanced by l-arg infusion secondary to increased nitric oxide bioactivity. Further studies of l-arg as a therapeutic modality in patients with endothelial dysfunction (ie, acute limb ischemia) are warranted.

Repair of a mycotic abdominal aortic aneurysm in a neonate using an everted jugular vein patch.

A 43-day-old boy presented with bacteremia after umbilical artery catheterization. Duplex ultrasound examination revealed a 1.1- × 1.6-cm mycotic infrarenal aortic aneurysm and an incidental asymptomatic occluded right common iliac artery. Resection and repair were completed by creating an everted, double-layered internal jugular vein patch. Screening ultrasound examination 10 months postoperatively demonstrated successful repair.

Explantation of infected aortic aneurysm and endograft with ascending aorta to mesenteric bypass for mesenteric ischemia.

A 65-year-old man presented with an infected perivisceral aortic aneurysm after previous treatment of an abdominal aortic aneurysm with an endograft. On presentation, he was septic and had occlusion of the celiac, superior mesenteric, inferior mesenteric, and bilateral renal arteries. He underwent a three-stage procedure: first, axillobifemoral bypass; then resection of the thoracoabdominal aorta; and finally bypass from the ascending aorta to the celiac and superior mesenteric arteries with a rifampin-soaked Gelsoft graft (Vascutek, Renfrewshire, Scotland). The abdominal pain resolved, and the patient remains symptom free 10 months postoperatively. This rare surgical revascularization technique offered a nontraditional solution to a difficult surgical issue.

Percutaneous endovascular aneurysm repair in morbidly obese patients.

OBJECTIVE: Endovascular aneurysm repair (EVAR) with percutaneous femoral access (PEVAR) has several potential advantages. Morbidly obese (MO) patients present unique anatomical challenges and have not been specifically studied. This study examines the trends in the use of PEVAR and its surgical outcomes compared with open femoral cutdown (CEVAR) in MO patients. METHODS: The American College of Surgeons National Surgical Quality Improvement Program files for the years 2005 to 2013 were reviewed. The study included all MO patients (body mass index [BMI] ≥40 kg/m2) undergoing EVAR. Patients were categorized as having CEVAR if they had any one of 11 selected Current Procedural Terminology (American Medical Association, Chicago, Ill) codes describing an open femoral procedure. The PEVAR group included any remaining patients who had only codes for EVAR and endovascular procedures. Linear correlation was used to evaluate temporal trends in the use of PEVAR among MO patients. Baseline comorbidities and surgical outcomes were compared between the PEVAR and CEVAR groups using χ2 tests or t-tests. RESULTS: There were 833 MO patients (470 CEVAR and 363 PEVAR) constituting 3.0% of all patients undergoing EVAR. The use of PEVAR in MO patients significantly increased from 27.3% of total EVARs in the years 2005 to 2006 to 48.6% in 2013 (P = .039). The two groups had similar baseline characteristics, including age, BMI, comorbidities, and emergency procedures, except for history of severe chronic obstructive pulmonary disease (29.6% CEVAR vs 22.6% PEVAR; P = .024). PEVAR patients had shorter duration of anesthesia (244 vs 260 minutes; P = .048) and shorter total operation time (158 vs 174 minutes; P = .002). PEVAR patients had significantly decreased wound complications (5.5% vs 9.4%; P = .039). There was a trend towards PEVAR patients being more likely to be discharged home than to a facility (93.6% vs 87.8%; P = .060). There was no difference in any other complication or mortality. A subgroup analysis of 109 superobese patients with BMI ≥50 kg/mg2 (59 CEVAR and 50 PEVAR) demonstrated no significant differences in outcomes between groups. CONCLUSIONS: PEVAR is increasingly used in MO patients and decreases operating time and rates of wound infection compared with CEVAR. The advantages of PEVAR seem to be lost in the superobese patients.

Fatigue and in vivo validation of a peritoneum-lined self-expanding nitinol stent-graft.

PURPOSE: To assess the fatigue and in vivo performance of a new stent-graft incorporating bovine peritoneum lining that is designed for application in peripheral vascular occlusive disease. METHODS: Bovine peritoneum-lined stent-grafts were subjected to accelerated in vitro pulsatile fatigue and axial/torsional fatigue testing designed to simulate 10 years of physiological strain on the devices. At specified times the devices were evaluated for stent fracture, suture failure, or tissue tearing. Seven dogs underwent bilateral common iliac artery (CIA) balloon angioplasty injury with unilateral placement of the peritoneum-lined stent-graft. Angiography and intravascular ultrasound were performed prior to treatment, after treatment, and prior to sacrifice at 30 days. Vessels were perfusion fixed and histologically evaluated at 5 regions: above stent, proximal stent, mid stent, distal stent, and below stent. RESULTS: No evidence of stent, suture, or tissue failure was present during or after pulsatile and axial/torsional fatigue testing. At 30±0.3 days after implantation, all vessels were patent. The average lumen area at explantation across stented vessels was 25.45 mm(2). Lumen areas tended to be reduced above (23.57 mm(2)) and below (24.17 mm(2)) the stent. Lumen areas were consistent across stented regions at explantation (proximal stent 27.80 mm(2), mid stent 25.88 mm(2), and distal stent 25.81 mm(2)). The mean neointimal area in peritoneum-lined stents was 2.02±1.52 mm(2), with a neointima:media ratio of 1.03±0.50. These values were significantly lower in the above and below stent areas than in the stented regions, but there was no difference in either measure within the proximal, mid, or distal stent. CONCLUSION: The custom-designed peritoneum-lined stent-graft is promising for clinical peripheral applications due to its ability to resist relevant long-term physiological stresses and outstanding short-term patency rates in canine implantations.

Late graft explants in endovascular aneurysm repair.

OBJECTIVE: With more than a decade of use of endovascular aneurysm repair (EVAR), we expect to see a rise in the number of failing endografts. We review a single-center experience with EVAR explants to identify patterns of presentation and understand operative outcomes that may alter clinical management. METHODS: A retrospective analysis of EVARs requiring late explants, >1 month after implant, was performed. Patient demographics, type of graft, duration of implant, reason for removal, operative technique, length of stay, complications, and in-hospital and late mortality were reviewed. RESULTS: During 1999 to 2012, 100 patients (91% men) required EVAR explant, of which 61 were placed at another institution. The average age was 75 years (range, 50-93 years). The median length of time since implantation was 41 months (range, 1-144 months). Explanted grafts included 25 AneuRx (Medtronic, Minneapolis, Minn), 25 Excluder (W. L. Gore & Associates, Flagstaff, Ariz), 17 Zenith (Cook Medical, Bloomington, Ind), 15 Talent (Medtronic), 10 Ancure (Guidant, Indianapolis, Ind), 4 Powerlink (Endologix, Irvine, Calif), 1 Endurant (Medtronic), 1 Quantum LP (Cordis, Miami Lakes, Fla), 1 Aorta Uni Iliac Rupture Graft (Cook Medical, Bloomington, Ind), and 1 homemade tube graft. Overall 30-day mortality was 17%, with an elective case mortality of 9.9%, nonelective case mortality of 37%, and 56% mortality for ruptures. Endoleak was the most common indication for explant, with one or more endoleaks present in 82% (type I, 40%; II, 30%; III, 22%; endotension, 6%; multiple, 16%). Other reasons for explant included infection (13%), acute thrombosis (4%), and claudication (1%). In the first 12 months, 23 patients required explants, with type I endoleak (48%) and infection (35%) the most frequent indication. Conversely, 22 patients required explants after 5 years, with type I (36%) and type III (32%) endoleak responsible for most indications. CONCLUSIONS: The rate of EVAR late explants has increased during the past decade at our institution. Survival is higher when the explant is done electively compared with emergent repair. Difficulty in obtaining a seal at the initial EVAR often leads to failure ≤1 year, whereas progression of aneurysmal disease is the primary reason for failure >5 years.

In vivo assessment of endothelial function in human lower extremity arteries.

OBJECTIVE: Endothelial function has been measured in preclinical studies in human brachial and coronary arteries but not in lower extremity arteries affected by atherosclerosis. We describe a novel, first-in-man evaluation of endothelial function of the superficial femoral arteries (SFAs) in patients with peripheral arterial disease (PAD). METHODS: Enrolled were 25 patients with PAD requiring lower extremity angiography. Endothelial-dependent relaxation was measured using intravascular ultrasound (IVUS) imaging and a Doppler flow wire after the infusion of acetylcholine (Ach). IVUS-derived virtual histology of the same vessel was calculated. Endothelial-independent relaxation was measured with an infusion of nitroglycerin (200 µg). Levels of nitric oxide and serum nitric oxide metabolites were determined by laboratory analysis. RESULTS: Patients (48% male; mean age, 62 years) had a history of hypertension (80%), coronary disease (36%), and diabetes (40%). The mean SFA diameter was 5.2 ± 1 mm (range, 3.2-6.9 mm). Patients tolerated Ach infusion with no adverse events. Endothelial-dependent relaxation increased over baseline for all patients with Ach infusion of 10(-6) to 10(-4). At Ach 10(-4), diameter (0.5%) and area (1.8%) changes in the diseased SFAs were modest and insignificant; however, average peak velocity of blood flow significantly increased 26%, 46%, and 63% with an Ach 10(-6) to 10(-4) infusion. Calculations of limb volumetric flow (68% at Ach 10(-4)) were significantly increased after Ach infusion. Lower extremity nitric oxide levels were slightly lower than systemic venous levels (P = .04). Nitroglycerin infusion indicated normal smooth muscle responsiveness (3% diameter, 9% area, and 116% velocity change over baseline). IVUS-virtual histology plaque stratification indicated predominantly fibrous morphology (46%; necrotic core, 29%; calcium, 18%). Atheroma burden was 14.9 ± 5.5 mm(3)/cm and did not correlate with endothelial responsiveness. CONCLUSIONS: Endothelial function can be measured directly in human lower extremity arteries at the sites of vascular disease. Despite extensive atherosclerosis, endothelial function is still intact. These data support the application of regional endothelial-specific biologic therapies in patients with PAD.