Incremental prognostic value of myocardial perfusion single photon emission computed tomography for the prediction of cardiac death: Differential stratification for risk of cardiac death and myocardial infarction

Background - The incremental prognostic value of stress single photon emission computed tomography (SPECT) for the prediction of cardiac death as an individual end point and the implications for risk stratification are undefined. Methods and Results - We identified 5183 consecutive patients who underwent stress/rest SPECT and were followed up for the occurrence of cardiac death or myocardial infarction. Over a mean follow up of 642±226 days, 119 cardiac deaths and 158 myocardial infarctions occurred (3.0% cardiac death rate, 2.3% myocardial infarction rate). Patients with normal scans were at low risk (≤0.5%/y), and rates of both outcomes increased significantly with worsening scan abnormalities. Patients who underwent exercise stress and had mildly abnormal scans had low rates of cardiac death but higher rates of myocardial infarction (0.7%/y versus 2.6%/y; P<.05). After adjustment for prescan information, scan results provided incremental prognostic value toward the prediction of cardiac death. The identification of patients at intermediate risk of nonfatal myocardial infarction and low risk for cardiac death by SPECT may result in significant cost savings when applied to a clinical testing strategy. Conclusions - Myocardial perfusion SPECT yields incremental prognostic information toward the identification of cardiac death. Patients with mildly abnormal scans after exercise stress are at low risk for cardiac death but intermediate risk for nonfatal myocardial infarction and thus may benefit from a noninvasive strategy and may not require invasive management.