Long-term outcome of patients with intermediate-risk exercise electrocardiograms who do not have myocardial perfusion defects on radionuclide imaging

Background-The appropriate management of patients with intermediate-risk Du ke treadmill scores is not established. The purpose of this study was to de termine the long-term risk of subsequent cardiovascular events in patients with an intermediate-risk treadmill score who do not have myocardial perfus ion defects on radionuclide imaging. Methods and Results-The existing databases of the nuclear cardiology labora tories of 4 academic institutions were searched retrospectively. A total of 4649 patients were identified who had intermediate-risk Duke treadmill sco res (- 10 to 4), normal or near-normal exercise single photon-emission comp uted tomographic myocardial perfusion images using either thallium-201 or t echnetium-99m sestamibi, and no previous coronary revascularization. Follow -up was 95% complete. Cardiovascular survival was 99.8% at 1 year, 99.0% at 5 years, and 98.5% at 7 years, Cardiac survival free of myocardial infarct ion was similarly high at 96.6% at 7 years. Cardiac survival free of myocar dial infarction or revascularization was 87.1% at 7 years. Near-normal scan s and cardiac enlargement were independent predictors of time to cardiac de ath. Seven-year cardiac survival was still high at 97.0% in the 357 patient s with near-normal scans and normal cardiac size and somewhat lower, at 89. 0%, in the 167 patients with cardiac enlargement. Conclusions-Patients with an intermediate-risk treadmill score but with nor mal or near-normal exercise myocardial perfusion images and normal cardiac sizes are at low risk for subsequent cardiac death and can be safely manage d medically until their symptoms warrant revascularization. The appropriate management of patients with cardiac enlargement will remain a matter of cl inical judgment.