The purpose of this study was to compare the prognostic value of left ventricular ejection fraction (LVEF) and myocardial perfusion reserve (MPR) assessed with PET in patients with ischemic heart disease (IHD). Myocardial perfusion is the main determinant of left ventricular function in patients with IHD. The prognostic value of LVEF has been widely established. In addition, MPR determines survival in patients with hypertrophic and dilated cardiomyopathies. In the present study, we evaluated whether MPR also determines survival in patients with IHD.
Methods: Between 1995 and 2003, 480 consecutive patients with chronic IHD underwent dipyridamole stress and rest 13N-ammonia PET to determine MPR. Additionally, 18F-FDG PET was performed for viability (mismatching defects), infarction (matching defects), and left ventricular function assessment. Patients were followed for all causes of mortality and major cardiovascular events.
Results: In 463 of the 480 patients, valid MPR could be measured (368 men; mean age, 66+/-11 y; LVEF, 35%+/-15%). One hundred nineteen patients underwent a PET-driven revascularization (67 through percutaneous coronary intervention and 52 through coronary artery bypass grafting). The remaining 344 patients were the subject of this study. The overall MPR was 1.71+/-0.50 (intertertile boundaries, 1.49 and 1.84). After adjustment for age and sex, MPR was associated with a hazard ratio for cardiac death of 4.11 (95% confidence interval, 2.98-5.67) per SD decrease, whereas the risk for LVEF was 2.76 (2.00-3.82) per SD decrease.
Conclusion: Patients with IHD with a low MPR are at high risk of cardiac death. MPR is a more sensitive predictor for cardiac death than is LVEF.