ASYMPTOMATIC CARDIAC ISCHEMIA PILOT (ACIP) STUDY - EFFECTS OF CORONARY ANGIOPLASTY AND CORONARY-ARTERY BYPASS GRAFT-SURGERY ON RECURRENT ANGINA AND ISCHEMIA

Objectives. The Asymptomatic Cardiac Ischemia Pilot (ACIP) study showe d that revascularization is more effective than medical therapy in sup pressing cardiac ischemia at 12 weeks. This report compares the relati ve efficacy of coronary angioplasty or coronary artery bypass graft su rgery in suppressing ambulatory electrocardiographic (ECG) and treadmi ll exercise cardiac ischemia between 2 and 3 months after revasculariz ation in the ACIP study. Background. Previous studies have shown that coronary angio plasty and bypass surgery relieve angina early after th e procedure in a high proportion of selected patients, However, allevi ation of ischemia on the ambulatory ECG and treadmill exercise test ha ve not been adequately studied prospectively after revascularization. Methods. In patients randomly assigned to revascularization in the ACI P study, the choice of coronary angioplasty or bypass surgery was made by the clinical unit staff and the patient. Results. Patients assigne d to bypass surgery (n = 78) had more severe coronary disease (p = 0.0 01) and more ischemic episodes (p = 0.01) at baseline than those assig ned to angioplasty (n = 92), Ambulatory ECG ischemia was no longer pre sent 8 weeks after revascularization (12 weeks after enrollment) in 70 % of the bypass surgery group versus 46% of the angioplasty group (p = 0.002), ST segment depression on the exercise ECG was no longer prese nt in 46% of the bypass surgery group versus 23% of the angioplasty gr oup (p = 0.005). Total exercise time in minutes on the treadmill exerc ise test increased by 2.4 min after bypass surgery and by 1.4 min afte r angioplasty (p = 0.02). Only 10% of the bypass surgery group versus 32% of the angioplasty group still reported angina in the 4 weeks befo re the 12-week visit (p = 0.001). Conclusions. Angina and ambulatory E CG ischemia are relieved in a high proportion of patients early after revascularization. However, ischemia can still be induced on the tread mill exercise test, albeit at higher levels of exercise, in many patie nts. Bypass surgery was superior to coronary angioplasty in suppressin g cardiac ischemia despite the finding that patients who underwent byp ass surgery had more severe coronary artery disease.