Value of absence of a transient myocardial perfusion defect during stress myocardial perfusion study in patients undergoing major vascular surgery

Abstract

Pre-operative cardiac assessment is important in the evaluation of patients undergoing major vascular surgery. Our study aims to evaluate the value of absence of a transient myocardial perfusion defect during radionuclide myocardial perfusion study for prediction of cardiac events (myocardial infarction, sudden cardiac death, unstable angina, coronary artery revascularization and congestive heart failure) in patients undergoing major vascular surgery. We studied 63 consecutive patients (ages 35-83 [avg. 64], male 39, female 24) with radiographically proven, abdominal aortic aneurysm or severe aortofemoral occlusive disease who underwent major vascular surgery (abdominal aortic aneurysm repair [38] or aortofemoral bypass [25]). The subjects all had multiple coronary artery risk factors (hypertension 48, diabetes 10, hyperlipidemia 23, tobacco use 39, family history of coronary artery disease 10), but a negative pre-operative stress myocardial perfusion study for myocardial ischemia. Of these 63 patients, 17 patients were able to exercise and achieve their adequate 85% maximal predicted heart rate. Thirty-eight patients received adenosine infusion of 140 microg/kg/min for 6 min. Six patients received dipyridamole infusion of 0.56 mg/kg over 4 min. Two patients received dobutamine infusion at 5, 10, 20, 30, and 40 mg/kg/min. Of the 63 patients, 60 received 3-4 mCi of thallium-201 ((201)Tl) and 3 patients received 8-9 mCi of technetium-99m (99mTc) at rest and 25-30 mCi 99mTc during stress. The subjects all underwent major vascular surgery and were followed up to one year for any cardiac events. Of the 63, who underwent pre-operative cardiac assessment with myocardial perfusion testing, 25 had a fixed myocardial perfusion defect (scar) and none had evidence of transient myocardial perfusion defect (ischemia). One subject had coronary artery bypass grafting 11 months after aortofemoral bypass surgery. One died from a stroke one month after aortofemoral bypass surgery. Of the remaining 61 patients, none had any cardiac events up to one year after major vascular surgery.