The role of radionuclide angiocardiography in the preoperative prediction of pain relief and prolonged survival following coronary artery bypass grafting.

Radionuclide angiocardiography (RNA) provides noninvasive measurements of left ventricular function during rest and exercise, which appear to reflect the magnitude of fibrosis and ischemia in patients with coronary artery disease. This investigation evaluated the usefulness of these measurements for providing prognostic information, useful in selecting therapy. The RNA study group included 278 patients with a low resting ejection fraction and coronary artery disease documented by angiography. Patients were followed for up to three years to define survival and incidence of complete pain relief. The 172 patients treated medically had less favorable survival and pain relief than the 106 surgically treated patients. In the medically treated patients, a positive RNA defined a subgroup of 113 patients, with a 20% lower 3-year survival than the 59 patients with a negative RNA. Moreover, comparison of patients receiving medical and surgical therapy following a positive RNA documented a clear improvement in both survival and pain relief for those who showed significant ischemia during exercise and subsequently underwent coronary bypass procedures. In patients with a negative RNA, medical and surgical therapy resulted in a similar survival rate and little difference in pain relief. Calculations comparing the maximal potential increase in survival and complete pain relief, using multiple criteria known to provide prognostic information, identified the exercise response on RNA as the single most important variable for selection of therapy. Therefore, the left ventricular response to exercise provides important prognostic information in patients with low resting ejection fractions, and the results of this procedure can be used to define subgroups of patients who will and will not benefit from coronary artery bypass grafting.