Determination of improved myocardial perfusion after aortocoronary bypass surgery by exercise 81Rb scintigraphy

Practical and noninvasive means are needed for evaluating efficacy of coronary bypass surgery (CBS) in improving blood flow (CBF) to ischemic myocardium in coronary patients. Revascularization was assessed in 15 patients by pre- and post-CBS rest and exercise rubidium-81 myocardial images with a scintillation camera equipped with pinhole collimator and high-energy shield. Ischemic areas were detected by decreased 81Rb activity after exercise compared to rest. Before CBS all patients had exercise angina (EA), positive treadmill ECG (TECG), and abnormal exercise 81Rb scans. After CBS all 15 patients had increased physical activity before angina or completion of treadmill exercise with increased heart rate-blood pressure product (HRBP) (+63 +/- 3.2 x 10(2) bpm - mm Hg) in 14 of 15 patients indicating increased CBF; four had positive TECG, and five had EA. The increased HRBP in 14 patients was associated with improved post-CBS exercise 81Rb scans: six had normal patterns while nine were improved with less ischemic patterns. Further, lack of angina and increased exercise tolerance correlated closely with increased 81Rb myocardial perfusion. Thus pre- and postoperative rest and exercise 81Rb scintigraphy gives an accurate, noninvasive, objective approach for evaluation of CBF following CBS and demonstrates the usefulness of this revascularization procedure in coronary patients