Asymptomatic cardiac ischemi pilot (ACIP) study: Impact of anti-ischemi therapy on 12-week rest electrocardiogram and exercise test outcomes

Objectives This report from the Asymptomatic Cardiac Ischemi Pilot (ACIP) study examines differences in the magnitude of reduction of myocardial ischemi as determined by exercise treadmill testing in patients randomized to three different treatment strategies: angina-guided medical therapy, ischemia-guided medical therapy and coronary revascularization. Background No prospective randomized clinical trials in patients with exercise electrocardiographic (ECG) abnormalities and asymptomatic cardiac ischemi on ambulatory ECG monitoring have compared the impact of different treatment strategies, including coronary revascularization, in terms of reducing myocardial ischemia. Methods The ACIP exercise protocol was used. Exercise variables measured included final exercise stage; presence of exerciseinduced angin or ischemia; time to angina; time to 1-mm ST segment depression; number of exercise ECG leads with abnormalities; maximal depth of ST segment depression in any lead; sum of ST segment depression; ST/HR index; and rate-pressure product at time to angina, at time to 1-mm ST segment depression and at peak exertion. Results Peak exercise time was increased by 0.5, 0.7 and 1.6 min in patients assigned to the angina-guided, ischemiaguided and coronary revascularization strategies, respectively, from the qualifying visit to the 12-week visit (p < 0.001). At the qualifying visit, the sum of exercise-induced ST segment depression was 9.4 ± 5.0 (mean ± SD), 9.6 ± 4.7 and 9.9 ± 5.5 mm (p = NS) in the three treatment strategies, respectively. At the 12-week visit, the sum of exercise-induced ST segment depression was 7.4 ± 5.7, 6.8 ± 5.3 and 5.6 ± 5.6 mm (p = 0.02) in the three treatment strategies, respectively. Each treatment strategy resulted in significant reduction in all exercise-induced variables of myocardial ischemi measured at 12 weeks. Conclusions Coronary revascularization significantly reduced the extent and frequency of exercise-induced myocardial ischemi compared with either medical strategy. The prognostic impact of these observations should be evaluated in large-scale multicenter clinical trial.