Perfusion Imaging

A cohort of 1,702 patients was referred for exercise Tcsestamibi single-photon emission computed tomography (SPECT) from January 1, 1991, to January 1, 1993, for whom follow-up could be obtained. Patients were followed for 20 6 5 months. Of the 1,131 who had normal or equivocal scan results, 1 cardiac death and 1 myocardial infarction occurred (0.2% event rate), and 17 cardiac deaths and 26 nonfatal infarctions were reported in the 571 patients with abnormal scans (7.5% event rate). This low event rate in patients with normal or near-normal scans was similar in patients with a low (,0.15), intermediate (0.15 to 0.85) and high (.0.85) postexercise treadmill test (ETT) likelihood of coronary artery disease (CAD). In contrast, if the scan was abnormal, the hard cardiac event rates were 3.8%, 7.9% and 10.8% in these three groups, respectively. There were 1,282 patients with interpretable exercise electrocardiogram responses, of whom 231 were judged to have ,15% post-ETT likelihood of CAD. The SPECT had incremental prognostic value in these patients, in that 167 had a normal scan with a 0% event rate and 64 had an abnormal scan with a 6.2% event rate. Of the 503 patients with an intermediate or high post-ETT likelihood of CAD, SPECT also provided incremental prognostic value in the 274 patients with a normal scan who had a 0% event rate, whereas the 229 patients with an abnormal scan had a 7.9% event rate. Risk stratification was also significantly enhanced in the 420 patients with uninterpretable ETT results. No events occurred in those with a normal scan. Finally, the nuclear scan strategy was shown to be cost-effective in patients with intermediate-to-high post-ETT likelihood of CAD if only patients with abnormal scans are referred to catheterization. Originally published in the Journal of the American College of Cardiology,