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and symptomatic venous hypertension in the remaining 8 (40%). Technical success and resolution of the symptoms was achieved in all cases. Locations CS placements are summarized in the Table. The mean follow-up was 8.4 months, 3 cases (15%) of thrombosis occurred within the first 3 months of stent placement requiring percutaneous thrombectomy and percutaneous transluminal angioplasty (PTA). Three patients required PTA for restenosis. The overall primary patency, assisted primary patency, and secondary patency were 66%, 94%, and 100% at 12 months, respectively.Conclusion: Endovascular therapy with CS for CVOD is safe and effective in hemodialysis patients. In the present series, we demonstrated promising results with higher primary and secondary patency than angioplasty and bare-metal stents. CS placement should be considered in recalcitrant lesions; however, further prospective and randomized studies are necessary to determine whether CSs provide superior long-term results to those achieved with PTA and bare-metal stents.Objective: This study compared the late outcomes in patients who survived 30 days after endovascular aneurysm repair (EVAR) and open repair (OR) for ruptured abdominal aortic aneurysms (RAAA).Methods: Retrospective analysis was done of prospective data from all RAAA presented to our service from 1998 to 2009. Of 252 RAAA, 13 patients (5%) were treated nonoperatively (logistic issue, 2; poor prognosis, 10; death during CT scan, 1). Two patients had a nonrelated diagnosis (gastrointestinal bleeding and type A dissection). A total of 122 patients (49%) were treated by EVAR, and 115 (46%) with OR. The 30-day survival for EVAR and OR was 85% (103 of 122) and 67% (78 of 115), respectively. Mean follow-up was 43 Ϯ 34.3 months (range, 1-132 months). Loss to follow-up for EVAR was Ͻ1%; for OR, 12%.Results: The actual overall survival rate of all early EVAR and OR survivors was 62% (64 of 103) and 45% (43 of 78), respectively. Cumulative survival rates at 1, 3, and 5 years were 90%, 79%, and 69% for EVAR and 87%, 78% and 60% for OR, respectively.Conclusions: This first series of long-term results after EVAR vs OR for RAAA shows an at least equivalent cumulative survival rate of 69% vs 60% at 5 years. Taking into account the short-term mortality reduction of EVAR vs OR (14% vs 33%, relative risk reduction of 62%), EVAR for RAAA is superior to open repair from the perspective of long-term as well as shortterm outcomes. EVAR should become the standard of care for all RAAA in patients with suitable anatomy for EVAR.

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The degradation at 150°C. of polyvinyl chloride in the presence of base is studied by means of ultraviolet, visible, and infrared spectra. The reaction of polyvinyl chloridebase systems at 150°C. is viewed as a base accelerated dehydrochlorination of polyvinyl chloride proceeding through initiation, propagation, and termination phases. Polyene units with sixteen double bonds in conjugation are considered to be the most probable component of polyene structures contributing to the longest wave length absorption maxima recorded at 550 mμu. Dichroism to polarized light is observed in a plasticized, oriented, base degraded polyvinyl chloride film. This dichroism is considered a confirmation of the assigned polyene structure. The infrared spectra obtained reveal the development, as the reaction progresses, of conjugated carbon‐carbon double bonds, conjugated carbonyl groups, bonded hydroxyl groups such as from hydroperoxides and/or alcohols, and the eventual formation of carboxyl groups. The mechanism of the oxidative degradation at 150°C. is attributed to the attack, after dehydrohalogenation, by molecular oxygen at the olefinic double bonds to form peroxide radicals which by radical chain transfer yield hydroperoxides that degrade to carbonyl containing products.