Functional and anatomic correlates of markedly abnormal stress tests

The functional state and coronary anatomy of 120 patients evaluated primarily because of a markedly positive ischemic exercise stress test (> 2 mm ST depression) is presented. Twenty-seven patients were asymptomatic (group A), 36 patients (group B) had type I angina (Canadian classification) and 57 patients (group C) had angina with only minor limitations (type II angina). All patients underwent exercise stress testing (Bruce protocol) within 2 months of cardiac catheterization. No significant intergroup differences were observed in exercise variables including time of onset of ischemia, maximal heart rate achieved, rate-pressure product, duration of exercise or mean change in blood pressure. Two patients in group A had normal coronary arteriograms. Comparison of the remaining asymptomatic patients in group A with patients in groups B and C revealed no significant differences in the number of coronary arteries involved, main left coronary artery disease, coronary score or the frequency of collateral circulation. In group A, 18% of collateral vessels were in jeopardy compared with 52% in groups B and C (p < 0.05). Triple vessel disease was present in 57% and left main coronary artery disease in 16% of the total group. The only exercise variable useful in identifying patients with severe coronary disease was an abnormal exercise blood pressure response. This study indicates that a markedly ischemic stress test, regardless of the functional state of the patient, identifies patients, including those without symptoms, who have severe coronary disease. Except for blood pressure response, other exercise variables are of limited value in identifying patients with severe coronary disease once a markedly ischemic stress test is present.