The prognostic value of stress/rest gated myocardial perfusion SPECT in patients with known or suspected coronary artery disease

Introduction: Gated myocardial perfusion SPECT has diagnostic and prognostic values in coronary artery disease (CAD). We tried to determine prognostic values of the left ventricular perfusion & functional indices as well as transient left ventricular dilation (TID) derived from gated myocardial perfusion SPECT. Methods: 1820 patients who underwent gated myocardial perfusion SPECT (Gated SPECT) were studied. The summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS) were calculated. Cardiac events considered as nonfatal myocardial infarction, cardiac death, Coronary Care Unit admission and revascularization. Mean follow-up period after Gated SPECT was 23±10 months. Results: 1599 patients didn't have any events, while from remaining 221, six patients had an acute MI, 90 patients had CCU admission, 42 patients underwent revascularization and 84 patients died. There was statistically significant difference in the cardiac events based on age, sex, SSS, SRS, SDS, TPD, TID, left ventricular volumes and LVEF. Multivariable Cox regression analysis showed the most and independent predictors of cardiac events are age (P=0.001), SSS (P=0.01) and history of coronary angiography (CA) (P=0.01). History of CA had a greater than 4.4 fold increased incidence of a cardiac event. With increase in SSS for 1 score, 1.4 times and with increase one year in age 1.4 fold increase in future cardiac event were seen. Conclusion: There was a strong association between future cardiac events and clinical history, SSS, SRS, SDS, TPD, TID, left ventricular volumes and LVEF. The most and independent predictors were age, SSS and history of CA.