Multicenter prospective study of nonruptured abdominal aortic aneurysms. I. Population and operative management.

This article describes the patient population and operative management of 666 patients with nonruptured aneurysms of the abdominal aorta. Statistical significance of variables was determined by the chi-square test and logistic regression analysis. There were no statistically significant differences (p greater than 0.05) in mortality rate for abdominal aortic aneurysm (AAA) on the basis of indication for surgery (asymptomatic, 3.9%; asymptomatic but with evidence of enlargement, 4.9%; and symptomatic, 7.2%) or the urgency of operation (elective operation, 4.5%; and urgent operation, 7.1%). Characteristics of the 72 participating surgeons did not influence the operative mortality rate. A family history of AAA was documented in 6.1% of cases and was more common if the patient was female (p = 0.03) and less than 65 years of age (p = 0.04). Patients without clinical evidence of coronary artery disease had a 0.8% mortality rate from cardiac disease compared with 6.2% if any stigmata of coronary disease were present. Prior aortocoronary bypass surgery did not reduce the incidence of postoperative cardiac events or operative mortality rate. Patients having "routine" angiography did not have a less complicated operative course, fewer thrombotic complications, or lower mortality rate than those not having it. Those patients with an inflammatory AAA (4.5%) did not have a significantly higher incidence of pain. Heparin administration (84.8%) did not reduce the complications of graft thrombosis, "trash," distal thrombosis, and/or amputation. The 6.8% of patients requiring suprarenal aortic cross-clamping had a higher incidence of postoperative renal dysfunction (p = 0.02) and intraoperative blood loss (p less than 0.001), but cardiac events were not more frequent. When the aortic cross-clamping time was prolonged (more than 70 minutes), the requirement for crystalloid fluid administration increased (p less than 0.001) and postoperative myocardial infarction was more common (p = 0.004). After ligation of the left renal vein in 7.9%, renal damage or dialysis was more frequent (p = 0.01). Patients having an intra-abdominal graft (tube, 38.5% and biiliac, 30.7%) had fewer wound infections (p = 0.02) and graft thromboses (p less than 0.001) than the patients with a femoral anastomosis. When the internal iliac artery flow was interrupted bilaterally (12%), diarrhea (p = 0.03) and ischemic colitis (p = 0.03) were more frequent complications. Reimplantation of the inferior mesenteric artery was carried out in 4.8%. After renal artery bypass in 2.1%, the mortality rate was not increased, but the incidence of transient renal dysfunction was increased (p = 0.03).(ABSTRACT TRUNCATED AT 400 WORDS)