Faculty Bibliography

OBJECTIVE: Peripheral arterial disease (PAD) disproportionally affects racial groups in the United States. Few studies have analyzed the rates of PAD in the American Indian (AI)/ Alaskan Native (AN) population. In this paper we compare the prevalence of PAD in the AI/AN as compared to white and non-white Americans. METHODS: The study data were provided by Life Line Screening (Independence, Ohio). The cohort consists of self-referred individuals who paid for vascular screening tests. Mild to moderate and severe PAD were defined as having an ankle brachial index (ABI) in at least one extremity of < .9 and <.5 respectively. Univariate and multivariate analysis were performed to compare the rates of PAD between AI/AN, Caucasians, and non-whites. RESULTS: The original sample for which this study was obtained included 3,444,272 people. Of this group there was a predominance of females 64.5% (2,221,555) compared to 35.5% (1,222,716) males. The Native American/ Alaskan Native population was 2.8% of the sample (96,440). In our univariate analysis AI/AN had the highest rates of mild-moderate and severe PAD when compared to whites (OR 1.78 and 2.14 respectively) and non-whites (OR 1.52 and 1.82 respectively). We then controlled for atherosclerotic risk factors in our multivariate analysis and the AI/NA cohort had persistently higher rates of both moderate and severe PAD compared to whites (OR 1.32 and 1.40) but not compared to non-whites (OR .95 and .92). CONCLUSIONS: Here we present the largest epidemiology study of PAD in AI/NA to date. AI/NA people have disproportionately high rates of both mild-to moderate and severe PAD when compared to whites and non-white Americans. After controlling for atherosclerotic risk factors the rates of PAD remain high for AI/NA when compared to whites but not when compared to non-whites. While it is possible that a combination of diet and lifestyle choices are responsible for the high rates of PAD in this population, genetic factors may be involved as well, and deserve further investigation. Optimal medical management may help to prevent the complications of PAD in this patient population.

Background: Patients who present acutely with a femoral vein deep venous thrombosis (DVT) diagnosed by ultrasound are often treated with anticoagulation and instructed to follow up electively. This study sought to assess whether obtaining central imaging in this cohort of patients results in an increased diagnosis of iliocaval DVT and consequently an increased consideration for interventional treatments to effect thrombus removal. Methods: This study was a retrospective review of a prospectively maintained RedCap database from November 2014 through August 2016, which is coordinated by the Venous Thromboembolic Center at our institution. Consecutive patients who were diagnosed by ultrasound with a femoral vein DVT were evaluated. The patients who underwent confirmatory central venous imaging (computed tomography venography, magnetic resonance venography; group A) were compared with the patients who did not undergo central venous imaging (group B). Demographic variables were collected. The outcomes evaluated were (1) the presence of iliocaval DVT, (2) candidacy for lytic-based therapies, (3) performance of lytic-based therapy, and (4) performance of any invasive treatment (lytic therapy, mechanical thrombectomy, inferior vena cava filter placement, or venous stenting). Additional outcomes included technical success of invasive treatment and complications associated with invasive treatment. Results:A total of 63 patients were identified who presented with a diagnosis of femoral vein DVT. Group A comprised 20 of 63 (31%) patients. Group B comprised the remainder, 43 of 63 (69%). The baseline demographics did not differ significantly, except for gender (Table). The number of patients who were diagnosed with an iliocaval DVT differed significantly (group A, nine [45%]; group B, nine [20%]; P <.0001). The number of patients who underwent lytic therapy differed significantly (group A, eight [40%] - seven at the index admission and one at 1 month; group B, 0 [0%]; P <.0001). The number of patients without relative contraindications to lytic therapy did not differ significantly (group A, 13 [65%]; group B, 34 [79%]; P =.35). The number of patients who underwent any invasive treatment differed significantly between the two cohorts (group A, 12/20 [60%]; group B, 4/43 [9%]; P =.0001). The majority of interventions were technically successful in both groups (group A, 11/12 [91.7%]; group B, 4/4 [100%]; P = 1.00). Conclusions: This study suggests that a significant percentage of patients diagnosed by ultrasound with femoral vein DVTs have a concomitant iliocaval DVT. The data suggest that in patients with a femoral vein DVT, central venous imaging may be indicated to identify potentially treatable iliocaval thrombosis. Long-term data will be required to see if this results in a decrease in post-thrombotic syndrome on a population basis. (table present)

Pulmonary embolism (PE), a potentially life-threatening entity, can be treated medically, surgically, and percutaneously. In patients with right ventricular dysfunction (RVD), anticoagulation alone may be insufficient to restore cardiac function. Because of the morbidity and mortality associated with surgical embolectomy, clinical interest in catheter-directed interventions (CDI) has resurged. We describe specific catheter-directed techniques and the evidence supporting percutaneous treatments.

OBJECTIVES: Nutcracker syndrome, or mesoaortic compression of the left renal vein (LRV), with associated symptoms related to venous hypertension in the left kidney, is a rare entity that may result in severe symptoms requiring operative intervention. We report on three patients who presented with nutcracker syndrome, including one patient with a circumaortic LRV resulting in posterior nutcracker syndrome, who underwent successful endovascular treatment with renal vein stenting. A review of existing literature on endovascular management of nutcracker syndrome follows. METHODS: Three women (age range 28 to 43 years) presented with symptoms and imaging studies consistent with nutcracker syndrome. Symptoms included pelvic and flank pain in all three patients, and episodes of hematuria in two. Imaging studies demonstrated compression of the LRV between the superior mesenteric artery and aorta in two of the patients. The third patient was noted to have a circumaortic LRV. RESULTS: All three patients underwent venography and LRV stenting. Stents included a 12 x 40 mm self-expanding nitinol stent, 14 x 60 mm Wallstent, and 16 x 40 mm Wallstent. All patients were placed on clopidogrel post-operatively. The duration of follow-up ranged from six to twenty-seven months. At follow up, all three patients reported significant symptomatic improvement, and duplex ultrasonography demonstrated stent patency in all. CONCLUSIONS: Nutcracker syndrome is a rare condition that can be successfully treated with renal vein stenting via an endovascular approach. Results are encouraging at follow-up periods beyond two years.

OBJECTIVE: This review explores the current literature on the natural history, diagnosis, and management of mesenteric venous thrombosis (MVT) in the modern era. METHODS: A review of the contemporary literature from 1997 to 2016 on MVT and its pathogenesis, diagnosis, and treatment was performed. RESULTS: MVT is an insidious and lethal disease associated with acute mesenteric ischemia. The prevalence of MVT has increased sharply during the past two decades commensurate with an increase in radiographic imaging for abdominal complaints. The optimal treatment of and approach to MVT is controversial, given the poorly understood natural history of this rare disease. Both endovascular and open surgical strategies in addition to systemic anticoagulation have been used as adjuncts to treat MVT with limited success. Despite advances in treatment, mortality associated with MVT is still high. Furthermore, recent studies have shown that failure to recanalize the portomesenteric venous system leads to an increased risk for development of sequelae of portal hypertension. CONCLUSIONS: MVT is a challenging disease to treat, given the difficulty in establishing a prompt initial diagnosis and the inability to reliably monitor patients for evidence of impending bowel infarction. Careful selection of patients for endovascular, open, or hybrid approaches is key to achieving improved outcomes. However, the paucity of prospective data and our evolving understanding of the natural history of MVT make consensus treatment strategies difficult to ascertain.

BACKGROUND: Mesenteric venous thrombosis (MVT) is a relatively uncommon but potentially lethal condition associated with bowel ischemia and infarction. The natural history and long-term outcomes are poorly understood and under-reported. METHODS: A single-institution retrospective review of noncirrhotic patients diagnosed with MVT from 1999 to 2015 was performed using International Classification of Diseases, Ninth Revision and radiology codes. Patients were excluded if no radiographic imaging was available for review. Eighty patients were identified for analysis. Demographic, clinical, and radiographic data on presentation and at long-term follow-up were collected. Long-term sequelae of portal venous hypertension were defined as esophageal varices, portal vein cavernous transformation, splenomegaly, or hepatic atrophy, as seen on follow-up imaging. RESULTS: There were 80 patients (57.5% male; mean age, 57.9 +/- 15.6 years) identified; 83.3% were symptomatic, and 80% presented with abdominal pain. Median follow-up was 480 days (range, 1-6183 days). Follow-up radiographic and clinical data were available for 50 patients (62.5%). The underlying causes of MVT included cancer (41.5%), an inflammatory process (25.9%), the postoperative state (20.7%), and idiopathic cases (18.8%). Pancreatic cancer was the most common associated malignant neoplasm (53%), followed by colon cancer (15%). Twenty patients (26%) had prior or concurrent lower extremity deep venous thromboses. Most patients (68.4%) were treated with anticoagulation; the rest were treated expectantly. Ten (12.5%) had bleeding complications related to anticoagulation, including one death from intracranial hemorrhage. Four patients underwent intervention (three pharmacomechanical thrombolysis and one thrombectomy). One patient died of intestinal ischemia. Two patients had recurrent MVT, both on discontinuing anticoagulation. Long-term imaging sequelae of portal hypertension were noted in 25 of 50 patients (50%) who had follow-up imaging available. Patients with long-term sequelae had lower recanalization rates (36.8% vs 65%; P = .079) and significantly higher rates of complete as opposed to partial thrombosis at the initial event (73% vs 43.3%; P < .005). Long-term sequelae were unrelated to the initial cause or treatment with anticoagulation (P = NS). CONCLUSIONS: Most cases of MVT are associated with malignant disease or an inflammatory process, such as pancreatitis. A diagnosis of malignant disease in the setting of MVT has poor prognosis, with a 5-year survival of only 25%. MVT can be effectively treated with anticoagulation in the majority of cases. Operative or endovascular intervention is rarely needed but important to consider in patients with signs of severe ischemia or impending bowel infarction. There is a significant incidence of radiographically noted long-term sequelae from MVT related to portal venous hypertension, especially in cases of initial complete thrombosis of the mesenteric vein.

OBJECTIVE/BACKGROUND: Aorto-bifemoral bypass remains the gold standard for treatment of aortoiliac occlusive disease (AIOD) in patients with advanced (TASC D) lesions, but has significant associated morbidity and mortality. Treatment with a unibody stent-graft positioned at the aortic bifurcation is a potential endovascular option for the treatment of AIOD. The current study examines the safety, efficacy, and early patency rates of the Endologix AFX unibody stent-graft for treatment of AIOD. METHODS: A multicenter retrospective review was conducted of patients treated exclusively for AIOD with the AFX device. Primary, assisted primary, and secondary patency rates were noted. Clinical improvement was assessed using Rutherford classification and ankle brachial index. Mean duration of follow-up was 22.2 +/- 11.2 months. Ninety-one patients (56 males [62%]) were studied. RESULTS: Sixty-seven patients (74%) presented with lifestyle-limiting intermittent claudication and the remaining 24 (26%) had critical limb ischemia. Technical success was 100%. Complications included groin infection (n = 4 [4%]), groin hematoma (n = 4 [4%]), common iliac rupture (n = 4 [4%]), iliac dissection (n = 4 [4%]), and thromboembolic event (n = 3 [3%]; one femoral, one internal iliac artery, and one internal iliac with bilateral popliteal/tibial thromboemboli). Thirty-day mortality was 1% (1/91) resulting from a case of extensive pelvic thromboembolism. At 1 year, 73% of patients experienced improvement in Rutherford stage of -3 or greater compared with baseline. Nine patients (10%) required 16 secondary interventions. At all time points, primary patency rates were > 90%, assisted patency rates were > 98%, and secondary patency rates were 100%. CONCLUSION: This is the largest study to examine the use of the Endologix AFX unibody stent-graft for the treatment of AIOD. Use of the AFX stent-graft appears to be a safe and effective endovascular treatment for complex AIOD.

OBJECTIVE: To report the 5-year outcomes from the Endurant Stent Graft System in the U.S. regulatory trial (bifurcated Endurant; Medtronic Santa Rosa, Calif). METHODS: The study was a prospective, multicenter, regulatory trial performed at 26 U.S. sites. From June 2008 to April 2009, 150 patients with abdominal aortic aneurysms (AAAs) were treated with the Endurant bifurcated graft. The main inclusion criteria included AAA diameter >5 cm (or 4-5 cm in diameter where the size increased more than 5 mm within the previous 6 months), neck length >/=10 mm, and neck angulation 5 mm in 5/83 (6.0%). Eighteen AAA-related secondary interventions were required in 15 patients (11%): 12 for endoleak management, 4 for limb occlusions, 1 for stenosis, and 1 for thromboembolism. Four of 5 limb occlusions reported were in the first 6 months. Survival and reintervention rates were better than the Talent eLPS study, which was conducted under similar inclusion exclusion criteria. CONCLUSIONS: The 5-year outcomes of the Endurant Stent Graft System in the U.S. regulatory trial continue to be positive. The device appears to be durable with limited adverse events through 5 years. Comparison with an older generation device suggests improving outcomes with newer devices.

INTRODUCTION/OBJECTIVES: Previous studies have demonstrated that women tend to have adverse aortic neck morphology leading to exclusion of some women from undergoing EVAR. OBJECTIVE: To investigate differences in aortic neck morphology in men vs women, changes in the neck morphology and sac behavior after EVAR, and investigate how these features may influence outcomes. METHODS: We conducted a retrospective review of elective EVARs (2004-2013). We excluded patients who underwent elective EVAR with no post-operative imaging available and those patients with fenestrated repairs. Using TeraRecon and volumetric analysis, several features were investigated. These included percent thrombus, shape, length, angulation of the neck, and changes in neck and abdominal aortic aneurysm diameter. RESULTS: 146 patients were found to meet inclusion criteria (115 men and 31 women) with similar baseline characteristics. Neck angulation was greater in women (23.9 degrees vs 13.5 degrees (P<0.028). The percent thrombus in women was higher than men (35.4%vs 31%P<0.02). Abdominal aneurysm's were smaller in women at 1 year (4.2cm vs 5.1cm, P<0.002) and secondary interventions were higher in men (11.3% vs 0% P<0.05). Other features such as neck shape, changes in neck diameter, neck length, percent oversizing of graft where not statistically different between genders. CONCLUSIONS: Gender differences in neck characteristics and changes in neck morphology do not appear to adversely affect EVAR outcomes. Longer follow up is necessary to further assess whether these findings are clinically durable.