Incremental Prognostic Value of Cardiac Function Assessed by ECG-Gated Myocardial Perfusion SPECT for the Prediction of Future Acute Coronary Syndrome

Abstract

The prognostic value of ECG-gated rest 201Tl/stress 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography for the prediction of acute coronary syndrome (ACS: myocardial infarction (MI) and unstable angina (UA)) and the implications of ejection fraction (EF) has not yet been defined in Japanese. The 1,895 patients were followed up for the occurrence ACS. The mean follow-up interval was 26.9+/-15.5 months. The 142 patients with revascularization within 60 days were censored. Summed stress score (SSS) and summed difference score (SDS) were calculated. The 19 MI and 29 UA occurred (1.1% and 1.6%, respectively). Univariate Cox analysis showed that hypertension (Wald 5.09, p<0.05), poststress EF (Wald 10.9, p<0.01), SSS (Wald 12.4, p<0.001) and SDS (Wald 18.7, p<0.001) were significant predictors of ACS. Multivariate Cox analysis showed that hypertension (Wald 4.27, p<0.05) and SDS (Wald 8.59, p<0.01) were independent predictors. When multiple clinical risk factors (number of coronary risk factors > or =2), significant ischemia (SDS > or =4) and low EF (EF <45%) were applied to multivariate Cox analysis, the combination of significant ischemia and low EF showed the highest predictive value (Wald 11.9; p<0.001) for future ACS. Poststress EF added incremental prognostic value for the prediction of ACS.