[Assessment of the results of aorto-coronary bypass surgery with the technetium 99m pyrophosphate scintigram (author's transl)].

In 40 patients with angiographically-documented coronary artery disease, technetium 99m pyrophosphate (99mTc-PYP) myocardial scintigrams were obtained prior to and four to six weeks after aorto-coronary bypass surgery. In the majority of patients, preoperative and postoperative exercise testing with simultaneous pulmonary artery pressure recordings was performed. In 22 of 30 patients with preoperatively increased 99mTc-PYP myocardial activity, no tracer accumulation could be found postoperatively. In the latter patients, there was also a significant increase in exercise capacity and lessening of ischemic ST-segment depression in the exercise ECG. In the remaining eight patients in whom increased tracer accumulation was found to persist postoperatively, there was no improvement in exercise capacity. In ten patients with no myocardial tracer accumulation preoperatively, unchanged myocardial scintigrams and a significant decrease of the ischemic ST-segment depression in the exercise ECG were seen postoperatively except in one patient with perioperative myocardial infarction. These results were also partially confirmed by repeated coronary angiography and ventriculography. Patent bypass grafts were associated with regional improvement in left ventricular function. The results indicate that postoperative absence of myocardial tracer accumulation appears due to amelioration of preexisting myocardial ischemia at rest. Thus, in the assessment of the results of aorto-coronary bypass surgery, the 99mTc-PYP scintigram offers an important diagnostic potential.