IMPROVED CARDIAC RISK STRATIFICATION IN MAJOR VASCULAR-SURGERY WITH DOBUTAMINE-ATROPINE STRESS ECHOCARDIOGRAPHY

Objectives. This study sought to optimize preoperative cardiac risk st ratification in a large group of consecutive candidates for vascular s urgery by combining clinical risk assessment and semiquantitative dobu tamine-atropine stress echocardiography. Background. Dobutamine-atropi ne stress echocardiography has been used for the prediction of periope rative cardiac risk in a small group of patients scheduled for electiv e major vascular surgery on the basis of the presence or absence of st ress-induced regional left ventricular wall motion abnormalities. Meth ods. Clinical risk assessment and dobutamine-atropine stress echocardi ography were performed in 302 consecutive patients presenting for majo r vascular surgery. The extent and severity of stress wall motion abno rmalities and the heart rate at which they occurred, in addition to th e presence of wall motion abnormalities at rest, were assessed. Result s. The absence of clinical risk factors (angina, diabetes, Q waves on the electrocardiogram, symptomatic ventricular tachyarrhythmias, age > 70 years) identified a low risk group of 100 patients with a 1% cardia c event rate (unstable angina). Dobutamine-atropine stress echocardiog raphic findings were positive in 72 patients. Twenty-seven patients ha d a perioperative cardiac event (cardiac death in 5, nonfatal infarcti on in 12, unstable angina pectoris in 10); all 27 patients had positiv e stress test results (positive predictive value 38%, negative predict ive value 100%). The semiquantitative assessment of the extent and sev erity of ischemia did not provide additional prognostic information in patients with positive test results. In contrast, the heart rate at w hich ischemia occurred defined a high risk group with a low ischemic t hreshold (38 patients with 20 events [53%]) and an intermediate risk g roup with a high ischemic threshold (34 patients with 7 events [21%]). All 5 patients with a fatal outcome and 8 of 12 with a nonfatal myoca rdial infarction were in the high risk group with a low ischemic thres hold. Conclusions. Clinical variables identify 33% of patients at very low risk for perioperative complications of vascular surgery in whom further testing is redundant. In all other candidates, dobutamine-atro pine stress echocardiography is a powerful tool that identifies those patients at intermediate risk and a small group at very high risk. Ris k stratification with a combination of clinical assessment and pharmac ologic stress echocardiography has the potential to facilitate clinica l decision making and conserve resources.