Endovascular repair and open repair resulted in similar long-term survival. The perioperative survival advantage with endovascular repair was sustained for several years, but rupture after repair remained a concern. Endovascular repair led to increased long-term survival among younger patients but not among older patients, for whom a greater benefit from the endovascular approach had been expected. (Funded by the Department of Veterans Affairs Office of Research and Development; OVER ClinicalTrials.gov number, NCT00094575.).

The preferential placement of autogenous fistulas may increase primary patency and decrease the incidence of revisions. Vein transpositions had similar secondary patency compared with simple fistulas, but required more revisions. The greatest benefit of a vein transposition fistula was seen in women and in patients with a history of access failure.

Intimal hyperplasia is a primary cause of failure after vascular reconstruction and may be affected by blood flow. We have studied the effects of increased blood flow on intimal hyperplasia in porous polytetrafluoroethylene grafts implanted in baboons. These grafts develop an endothelial lining by 2 weeks and neointimal thickening due to proliferation of underlying smooth muscle cells by 1 month. Creation of a distal arteriovenous fistula increased flow (from 230 +/- 35 to 785 +/- 101 ml/min, p less than 0.001) and mean shear (from 26 +/- 4 to 78 +/- 10 dynes/cm2, p less than 0.001) without causing a drop in pressure across the grafts. Fistula flow did not alter the pattern of endothelial coverage but did cause a marked reduction in the cross-sectional area of the neointima (from 2.60 +/- 0.52 to 0.42 +/- 0.07 mm2 at 3 months, p less than 0.01). Detailed morphometric analysis revealed an equivalent percentage decrease in smooth muscle cells and matrix content, suggesting that the primary effect of increased flow was to reduce smooth muscle cell number without affecting the amount of matrix produced by individual cells. The neointima remained sensitive to changes in flow at late times; ligation of the fistula after 2 months resulted in a rapid increase in neointimal thickness (from 0.60 +/- 0.03 mm2 after 2 months of fistula flow to 3.88 +/- 0.55 mm2 1 month after ligation of fistula, p less than 0.01). These results support the hypothesis that changes in blood flow affect the structure of diseased as well as normal vessels.

During the last decade (1980 to 1989) 186 patients with ruptured abdominal aortic aneurysm were admitted to a single urban hospital. Ninety-six percent of these patients had a prehospital systolic blood pressure less than 90 mm Hg. Management included paramedic field resuscitation and transport, an emergency department diagnostic protocol completed in an average of 12 minutes, rapid transport to a dedicated emergency operating room, aneurysmorrhaphy by general surgery chief residents under the supervision of specialist vascular surgeons, and skilled postoperative intensive care unit care. Nevertheless, 130 (70%) patients died in the first 30 postoperative days--3% in the emergency department, 13% in the operating room, 51% in the intensive care unit, and 3% on the ward or at home. Certain features--age greater than 80 years, female gender, persistent preoperative hypotension despite aggressive crystalloid and blood replacement, admission hematocrit less than 25, transfusion requirements exceeding 15 units--were associated with a greater than 90% likelihood of death. No patient with preoperative cardiac arrest survived more than 24 hours. From this experience we conclude that, although "optimal" prehospital, emergency department, operating room, and postoperative care can improve the outcome of patients with ruptured abdominal aortic aneurysms in shock, most such patients will die. Certain clinical features predict such excessive mortality rates after ruptured abdominal aortic aneurysms that withholding operation may be reasonable. Screening of patients at high risk for abdominal aortic aneurysm, followed by elective aneurysmorrhaphy, is clearly indicated.