Faculty Bibliography

Recanalization after extracranial internal carotid artery (ICA) occlusion is a rare phenomenon and the natural history of the disease is largely unknown. There have been few cases reported in the published data, including early recanalization after a cerebrovascular accident (CVA). We report a case of a 74-year-old man who presented with a CVA and a history of multiple CVAs in the past, the last episode being a year ago. Multiple imaging modalities, including duplex scans, computerized tomographic angiograms, and fluoroscopy-guided angiogram of bilateral carotid arteries, showed occlusion of the left ICA in the past. The duplex scan performed 8 months later demonstrated late spontaneous recanalization of the occluded left ICA. The patient underwent successful carotid endarterectomy. The pathophysiology, natural history, and possible surveillance strategy are discussed in this case report.

OBJECTIVE: Although anticoagulation remains the mainstay of treatment for deep venous thrombosis, the use of inferior vena cava (IVC) filters when anticoagulation has failed or when contraindicated remains a safe and effective treatment. Greenfield (Boston Scientific, Natick, Mass) and TrapEase (Cordis, Bridgewater, NJ) filters are arguably among the most popular filtration devices. The Greenfield filter (12F introducer) has been in use for >30 years and has been well studied. The TrapEase filter (6F introducer) has been used since 2000, with a limited number of studies. Good guidelines to help determine which filter to use in any given situation are lacking; therefore, this randomized study prospectively compared the clinical outcomes (access-site thrombosis, filter thrombosis, and symptomatic pulmonary embolism [PE]) between these filters. METHODS: Between July 2006 and November 2008, 156 patients (63 men, 93 women; mean age, 75 years; range, 38-101 years) were randomized: 84 to Greenfield and 72 to TrapEase IVC filter insertion in the infrarenal position using angiographic guidance. Postoperative follow-up comprised serial lower extremity and IVC/iliac vein (IV) duplex imaging (78.2%) at day 1, week 1, every 3 months for the first year, and every 6 months for the second year; clinical evaluation, and clinic visits. During this period, 349 patients (143 men, 206 women; mean age, 75 years; range, 24-96 years) were not randomized. RESULT: The indications for filter placement, in the 156 randomized patients, were gastrointestinal bleeding, 37; intracranial hemorrhage, 12; free-floating clot, 19; failure of anticoagulation, 29; PE, 27; prophylactic, 4; and others, 32. During a mean 12-month follow-up (range, 0-39 months), symptomatic IVC/IV thrombosis developed in five patients (6.94%) in the TrapEase group and none in the Greenfield group (P = .019). No filter migration, access-site thrombosis, misplacement, or IVC perforation occurred. Recurrent PE was suspected in one of the five patients with IVC/IV thrombosis. Overall mortality was 42.3% (66 patients), and 30-day mortality was 13.5% (21 patients: 10 TrapEase, 11 Greenfield). The study was initially designed to recruit 360 patients in both TrapEase and Greenfield filters in 2 years to demonstrate any statistical significance but was prematurely concluded due to the interim results. CONCLUSION: A higher rate of symptomatic IVC/IV thrombosis is associated with TrapEase filter placement. However, the TrapEase filter still has a selective clinical role in the prevention of thromboembolism in selected patients who are coagulopathic. This is the first randomized prospective study comparing IVC filters since their inception in 1967.

The objective of this study was to evaluate the feasibility of duplex scanning-derived access volume flow (DAVQ) to predict the success or failure of arteriovenous fistulae (AVF) after interventions. Eighty-eight DAVQ measurements were available for 60 AVF in 59 patients. In 25 cases, physical examination findings or inadequate dialysis suggested failing (11) or nonmaturing (14) AVF. Outflow stenoses (1-4; mean 1.2 +/- 0.8) were confirmed by contrast fistulograms in 23 cases (17 peripheral; 6 central). These 23 cases underwent successful endovascular repair (17 balloon angioplasty; 6 stents) and had pre- and postintervention DAVQ measurements within 2 weeks of the procedure. Each was measured three times in a nontortuous venous segment with laminar flow, and mean values were used for comparison. The overall mean DAVQ for 65 functioning AVF was 1,199 +/- 485 mL/min, whereas it was 652 +/- 438 mL/min (range 150-1,840 mL/min) for the remaining 23 failing or nonmaturing cases (p < .0001). Postintervention, the latter values changed to 867 +/- 517 mL/min (range 257-2,020 mL/min), with a p < .13. Of these, 11 were still nonfunctional after endovascular procedures and had a mean DAVQ of 404 +/- 111 mL/min (range 257-652 mL/min). The remaining 12 cases had a mean DAVQ of 1,280 +/- 382 mL/min (range 762-2,020 mL/min) and were functional and usable for at least 6 months of follow-up (p < .0001). It is interesting to note that none of the AVF cases with postintervention DAVQ < 700 mL/min became functional and usable, whereas all cases with a higher DAVQ underwent successful hemodialysis treatments. This early experience suggests that DAVQ can be used to predict the success or failure of an AVF following endovascular procedures. To our knowledge, this is the first such report.