708-3 Impact of Exercise SPECT Thallium Imaging on Patient Management and Outcome

This study examined the impact of exercise thallium imaging on patient (pt) management Ithe need for coronary angiography and revascularization) and outcome (hard cardiac event: cardiac death or non fatal acute myocardial infarction) in 2700 pts being evaluated for diagnostic purposes. None of the pts had prior coronary angiography, PTCA or CABG or Q-wave myocardial infarction. The SPECT images were normal in 2027 pts (Group 1) and abnormal in 673 pts (Group 2). The exercise ECG was positive in 190 pts (9%), negative in 1461 pts (72%) and non-diagnostic in 376 pts (19%) in Group 1. The corresponding numbers were 218 pts (32%), 240 pts (36%) and 215 pts (32%) in Group 2. Within 6 months after thallium imaging, 53 pts in Group 1 (3%) and 242 pts in Group 2 (36%) underwent coronary angiography (P=0.0001). The pts who underwent cardiac catheterization in Group 1 had higher pre-test probability of coronary disease (48±39% vs 39±27%) and lower exercise workload (7.1±3.2 vs 9.4±4.4 METs) than the pts who did not. The pts in Group 2 who underwent coronary angiography had more perfusion defects (8.8±4.8 vs 6.3±4.4 abnormal segments, P=0.0001) than pts who did not. Coronary revascularization within 3 months of coronary angiography was performed in 1 of the 53 pts in Group 1 (2%) and in 87 of 242 pts (30%) in Group 2 (P=0.0001). Among the remaining pts who had angiography and were treated medically there were no events in Group 1 and 15 events in Group 2. The event-free survival was significantly worse in Group 2 than Group 1 (Mantel-Cox statistic=5, P=0.02). Thus, the results of exercise SPECT thallium imaging are important in pt management and outcome. Coronary angiography, coronary revascularization and events are rare in pts with normal images