Incremental prognostic value of myocardial perfusion imaging in patients referred to stress single-photon emission computed tomography with renal dysfunction.

Coronary artery disease is the main cause of mortality and morbidity in patients with impaired renal function. The aim of this study was to evaluate the prognostic implications of single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in patients with impaired renal function. We included 7348 consecutive patients (mean age, 64+/-13 years; 51% men) referred for SPECT-MPI between March 2002 and October 2006. Renal function was estimated using the estimated glomerular filtration rate formula. Patients were followed up for the incidence of all-cause mortality. Patients with decreased glomerular filtration rate were more often older, with higher prevalence of conventional risk factors (P<0.001). After a median follow-up of 2.6 years (25th to 75th percentiles, 1.5 to 3.7), 693 (9.4%) patients died. The risk of death increased with worsening kidney function. At each stage of impaired renal function, patients with abnormal SPECT-MPI had increased hazard of adverse events (P<0.0001). Using Cox proportional hazards analysis, the magnitude of total perfusion deficit and ischemia on MPI were associated with worse outcome after adjusting for confounding variables including glomerular filtration rate and ejection fraction. SPECT-MPI adds modest incremental prognostic information to identify patients at higher relative risk of death across a wide spectrum of renal function.