A novel approach to autogenous hemodialysis access: paired brachial vein transposition in series.

Autogenous arteriovenous fistula (AVF) creation is the preferred method for long-term hemodialysis access. This report describes the novel use of paired brachial veins for the creation of an autogenous AVF in a patient without a traditional superficial venous conduit available. Application of this general concept might serve to expand the options for autogenous AVF creation.

The kissing-stent technique for treatment of distal aortic stenosis and protection of the inferior mesenteric artery orifice.

Focal infrarenal aortic stenosis is relatively rare. Traditionally, aortic endarterectomy and aortic bypass surgery have been used to treat these lesions. However, percutaneous transluminal angioplasty and stenting have become well-defined alternatives. A 62-year-old woman presented with bilateral ischemic rest pain. Angiography revealed a mid-infrarenal aortic stenosis adjacent to an enlarged, patent inferior mesenteric artery. Celiac artery and superior mesenteric artery stenoses were also present. The kissing-stent technique is a viable option for ensuring inferior mesenteric artery patency when treating distal aortic lesions by endovascular means in patients with asymptomatic multivessel mesenteric artery disease.

Challenging neck anatomy is associated with need for intraoperative endovascular adjuncts during endovascular aortic aneurysm repair (EVAR).

BACKGROUND: The purpose of this study was to determine which proximal seal zone characteristics were predictive of early and late type Ia endoleak development after endovascular aortic aneurysm repair (EVAR) for infrarenal abdominal aortic aneurysmal disease. METHODS: We evaluated 146 patients who underwent EVAR between January 2006 and March 2007. In the cohort, high-resolution computed tomography images of 100 (68.5%) patients were available, which showed detailed measurement of proximal neck parameters, including diameter, length, calcification, thrombus, suprarenal and infrarenal angles, and reverse taper morphology. Postprocessing of digital data sets was performed to obtain centerline-of-flow measurements. Relevant medical records and follow-up computed tomography scans were reviewed. RESULTS: Mean age of the patients was 72.7 years, with 78% being male. Of these patients, 66% did not satisfy the instructions for use for the Zenith EVAR device, and 50% did not satisfy the instructions for use for the AneuRx device. Nine patients had intraoperative type Ia endoleaks. A 100% assisted primary technical success rate was achieved with the adjunctive use of angioplasty (n = 4), uncovered stent (n = 3), and extension cuff (n = 2) placement. There was a significant association between type Ia endoleak development and magnitude of the infrarenal angle (p < 0.01); however, other parameters were not significant. At follow-up (mean, 587 days), no patient had a type Ia endoleak, and there were no aneurysm-related deaths. CONCLUSIONS: Our data indicate that infrarenal angle is related to intraoperative type Ia endoleak occurrence, but other factors often thought to be indicative of adverse neck anatomy are not significant predictors. Moreover, all type Ia endoleaks in this cohort were successfully eliminated intraoperatively, and durability was confirmed on postoperative surveillance. These data demonstrate that challenging neck anatomy is associated with the need for intraoperative endovascular adjuncts, and that effective and durable aneurysm exclusion should still be expected.

Quantitative assessment of abdominal aortic aneurysm geometry.

Recent studies have shown that the maximum transverse diameter of an abdominal aortic aneurysm (AAA) and expansion rate are not entirely reliable indicators of rupture potential. We hypothesize that aneurysm morphology and wall thickness are more predictive of rupture risk and can be the deciding factors in the clinical management of the disease. A non-invasive, image-based evaluation of AAA shape was implemented on a retrospective study of 10 ruptured and 66 unruptured aneurysms. Three-dimensional models were generated from segmented, contrast-enhanced computed tomography images. Geometric indices and regional variations in wall thickness were estimated based on novel segmentation algorithms. A model was created using a J48 decision tree algorithm and its performance was assessed using ten-fold cross validation. Feature selection was performed using the χ2-test. The model correctly classified 65 datasets and had an average prediction accuracy of 86.6% (κ=0.37). The highest ranked features were sac length, sac height, volume, surface area, maximum diameter, bulge height, and intra-luminal thrombus volume. Given that individual AAAs have complex shapes with local changes in surface curvature and wall thickness, the assessment of AAA rupture risk should be based on the accurate quantification of aneurysmal sac shape and size.

The effect of immunosuppression on lower extremity arterial bypass outcomes.

BACKGROUND: Myointimal hyperplasia is a pathologic result of the body's natural inflammatory response to injury of the blood vessels and a leading cause of peripheral arterial bypass failure. Because immunosuppressive agents are known to abate inflammation, we hypothesized the superior outcome of lower extremity bypass in renal transplant recipients compared with the hemodialysis population. METHODS: The vascular surgery registry at a single tertiary care center was retrospectively reviewed to identify patients who underwent lower extremity bypass procedures. All patients with a history of renal transplantation were selected for analysis. A consecutive group of bypass patients with dialysis-dependent renal failure was selected as a control cohort. The primary endpoint was amputation-free survival. RESULTS: Vascular reconstruction for chronic peripheral vascular disease yielded an amputation-free survival rate of 82% at 1 year for the those in the control group as compared with only 22% in the those with a history of renal transplantation (p = 0.02), which corresponded exactly with primary patency at 1 year. Patients were operated on for severe claudication (n = 1), rest pain (n = 1), and tissue loss (n = 17). There was no difference between the groups with regard to indication for operation or comorbid conditions. CONCLUSIONS: These data suggest a deleterious effect of immunosuppression on outcome of lower extremity bypass procedures at the doses required to prevent allograft rejection. This finding, which has been scarcely reported, underscores the importance of peripheral vascular disease screening in the transplant population and early intervention when clinically indicated.

Endoluminal treatment of type IA endoleak with Onyx.

Type IA endoleaks associated with endovascular aortic aneurysm repair are typically treated with endovascular adjuncts. Technical failure results when such maneuvers are unsuccessful, and endograft removal may, unfortunately, become necessary. The novel management of a recalcitrant type IA endoleak using the artificial embolization device, Onyx (Micro Therapeutics Inc, Irvine, Calif) is presented for the case of a nonagenarian with prohibitive surgical risk after conventional techniques had failed.