Feasibility of combined risk stratification with coronary CT angiography and stress myocardial SPECT in patients with chronic coronary artery disease

To examine the additional prognostic value of coronary CT angiography (CTA) over myocardial perfusion imaging (MPI) in patients with suspected or known coronary artery disease. A series of 157 patients (mean age 69 +/- 9 years; 76% male; median follow-up 49 months; range 12-82 months) underwent stress MPI with SPECT and coronary CTA within a 6-month interval. Summed stress score (SSS) and summed difference score (SDS) of stress MPI, number of vessels with stenosis, and presence of left main trunk stenosis and high-risk plaques on coronary CTA were examined. Primary endpoints were cardiac death, acute myocardial infarction, or unstable angina requiring revascularization. Secondary endpoints were revascularization > 60 days after the latter imaging test. All patients were followed up for at least 1 year (mean 45 +/- 19 months; range 12-82 months). Nine (6%) patients reached primary endpoints. Cardiac death occurred in 1 (0.6%) patient, myocardial infarction in 5 (3%), and unstable angina requiring hospitalization in 3 (2%). Elective revascularization within 60 days was performed in 31 (20%) patients. Sixteen (10%) patients required revascularization after > 60 days. Primary endpoint event-free survival rates were significantly lower in patients with myocardial ischemia (SDS >= 2) and high-risk plaques (HRP), and secondary endpoint event-free survival rates in patients with SSS >= 4 and 3VD. In multivariate analysis, Cox proportional hazards regression analysis revealed HRP (HR = 8.02; P = 0.006) and myocardial ischemia (HR = 11.487; P = 0.025) were significant predictors of primary endpoints, and 3VD of secondary endpoints (HR = 4.981; P = 0.008). Combined ischemia and HRP resulted in the significant increase of the model Chi square in prediction of primary end points from ischemia or HRP alone (17.4 vs. 9.41; P = 0.005, 17.4 vs. 9.39; P = 0.005, respectively). Coronary CT angiography may provide additional prognostic information over MPI.