Risk stratification of single or double vessel coronary artery disease and impaired left ventricular function using exercise radionuclide angiography

Patients with 3-vessel coronary artery disease (CAD) and normal left ventricular (LV) function have a worse prognosis if they manifest ischemia during exercise testing. The present study determines if exercise radionuclide angiography can aid in the risk stratification of patients with 1- or 2-vessel CAD and Impaired LV function (ejection fraction <50%). Sixty-five consecutive patients with these findings were followed for a median duration of 24 months (range 12 to 49). Eleven of the 65 patients (17%) had severely ischemic exercise radionuclide angiograms, defined as: a decrease in ejection fraction with exercise; ≥ 1.0 mm of ST-segment depression; and peak exercise workload ≤600 kg-m/min. During follow-up 11 patients had initial significant cardiac events: 4 cardiac deaths, i cardiac arrest, 4 myocardial infarctions and 2 bypass or angioplasty procedures for unstable angina ≥3 months after the exercise study. Four of 11 patients (36%) with severely ischemic exercise radionuclide angiograms had events, compared to 7 of 54 patients (13%) without ischemic radionuclide angiograms. Event-free survival at 18 months was 73% for patients with severe exercise ischemia versus 92% for those without ischemia (p < 0.05). Univarlate analysis showed that severe ischemia on radionuclide angiography was the only variable of several tested that significantly predicted future cardiac events (chi-square = 8.16, p < 0.005). Among patients with 1- or 2-vessel CAD and impaired resting LV function, severe ischemia on exercise radionuclide angiography identifies a subgroup at high risk for future cardiac events.