NONRUPTURED ABDOMINAL AORTIC-ANEURYSM - 6-YEAR FOLLOW-UP RESULTS FROMTHE MULTICENTER PROSPECTIVE CANADIAN ANEURYSM STUDY

Purpose: Based on the prospective analysis of data on 680 patients und ergoing surgery for nonruptured abdominal aortic aneurysm (AAA) and re corded in the Canadian Society for Vascular Surgery Aneurysm Registry, this study determines the late survival rate by comparison to an age- and sex-matched population, the causes of late death, the effect of h eart-related death on late survival, and the prognostic variables that are associated with late survival. Methods: To identify the variables that were associated with survival, statistical methods included Kapl an-Meier analysis and Cox regression analysis. The Canadian Society fo r Vascular Surgery Aneurysm Registry provided ongoing current follow-u p of patients. Results: The survival rate was 94.6% at 1 month, 90.7% at 1 year, 87.1% at 2 years, 81.0% at 3 years, 74.0% at 4 years, 67.7% at 5 years, and 60.2% at 6 years. The late survival rate of patients with AAA is significantly less than the age- and sex-matched normal po pulation (60.2% versus 79.2%). In the AAA group, heart-related causes of late death (44.4% versus 34.1%) and cerebrovascular causes (8.3% ve rsus 5.8%) were more frequent. The calculated 5-year heart-related mor tality rate is 14.3%. This is higher than the heart-related mortality rate for the age- and sex-matched population, which is 6.4%. Hence, th e risk of heart-related death for patients who have undergone AAA repa ir is increased by 1.6% per year. Vascular complications from aortic a neurysm repair or recurrent aneurysmal disease were an uncommon cause of late death: ruptured thoracic aneurysm, 1.5%; ruptured aortic false aneurysm, 1.5%; and aortoenteric fistula, 0%. This incidence appears to be less than reported in earlier series. By Cox regression analysis , the variables that were significant predictors of a lower late survi val rate were increased age, preoperative electrocardiogram indicating a previous myocardial infarction, and elevated serum creatinine level s. Conclusions: Because cardiac complications accounted for 68.8% (22/ 32) of the 4.7% in-hospital mortality rate (i.e., a heart-related mort ality rate of 3.2%), it seems reasonable to develop a strategy to redu ce the cardiac operative risk by identifying and treating patients at high risk before operation. However, it is doubtful that a preoperativ e program that screens and treats all patients can be cost-effective i n preventing late heart-related deaths.