The limits of generalized cardiac screening tests for predicting cardiac complications after infrainguinal arterial...

We examined the relative efficacies of different cardiac screening strategies for infrainguinal arterial bypass. The outcomes of 205 elective leg bypass procedures over a 10-year period, including myocardial infarction (MI), total cardiac complications, and mortality were tallied. Clinical risk factors popularized by Goldman and Eagle, and the results of dipyridamole thallium myocardial imaging (DThal) were recorded. The overall mortality rate was 3.4%, with a 3.4% incidence of MI and a 5.4% total cardiac complication rate. Both abnormal DThal (p = 0.011) and Goldman class II-IV (p = 0.030) were significant predictors of MI and cardiac death, but both suffered from poor specificity and positive predictive value. Because logistic regression analysis identified a correlation between angina, CHF, and an abnormal DThal, a customized screening strategy was developed to include the presence of angina, CHF and an abnormal DThal. Eighty-eight percent of patients suffering MI or death met these criteria, while only 11% of the complication-free group did. This screening strategy provided a superior sensitivity of 88%, specificity of 89%, positive predictive value of 25%, and 99% negative predictive value. A customized screening strategy (angina, CHF, abnormal DThal), developed from a 10-year experience with a single patient group, provided better predictive accuracy than any generalized screening formula.