Comparison of dipyridamole stress echocardiography and perfusion scintigraphy for cardiac risk stratification in vascular surgery patients

Dipyridamole single-photon emission computed tomography (SPECT) has a high negative predictive value for perioperative cardiac events, but events are infrequent in patients with a positive test. In contrast, dipyridamole echo cardiography is more selective for detection of multivessel disease and thu s may have a greater specificity for cardiac events. We therefore compared the ability of dipyridamole SPECT and echocardiography to predict periopera tive and long-term cardiac events in 133 patients referred for vascular sur gery, The group was also evaluated based on clinical features and election fraction. Four patients had surgery cancelled because of high risk and were excluded from further analysis. Among the 129 remaining patients, 21 had c oronary revascularization (n = 12) or an early cardiac end point (n = 9). T he sensitivity of SPECT for the prediction of early events (90%) was not si gnificantly different from that of echocardiography (66%, p = NS). The spec ificity of SPECT (68%) was less than that of echocardiography (88%, p < 0.0 01%), as was the accuracy (72% vs 84%, p = 0.02). These findings were repli cated after exclusion of patients with treatment end points. During long-te rm follow-up, 12 patients experienced greater than or equal to 1 event: 6 d ied from cardiac causes, 4 underwent revascularization, and 3 had myocardia l infarction. Thus, the specificity of SPECT and echocardiography for late events were 58% and 80%, respectively (p < 0.001). The 3-year survival of p atients without ischemia during echocardiography or at SPECT was not differ ent (93% vs 94%, p = NS). (C) 1998 by Excerpta Medica, Inc.