Patients determined to have a normal SPECT on the basis of stress imaging alone have a similar mortality rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. Our results support that additional rest imaging is not required in patients who have a normally appearing initial stress study. A significant reduction in radiation exposure can be achieved with such an approach.

The CACS and SPECT findings are independent and complementary predictors of short- and long-term cardiac events. Despite a normal SPECT result, a severe CACS identifies subjects at high long-term cardiac risk. After a normal SPECT result, our findings support performing a CACS in patients who are at intermediate or high clinical risk for coronary artery disease to better define those who will have a high long-term risk for adverse cardiac events.

Angina without obstructive CAD has a heterogeneous prognosis. A main determinant of major adverse events is the presence of 'some' coronary atherosclerosis, with unequivocal myocardial ischaemia being associated with worse clinical outcomes. Patients' quality of life is also worsened by the high incidence of hospitalization, angina recurrence, and repeated coronary angiography.

Background-Patients with chronic kidney disease (CKD) have worse cardiovascular outcomes than those without CKD. The prognostic utility of myocardial perfusion single-photon emission CT (MPS) in patients with varying degrees of renal dysfunction and the impact of CKD on cardiac death prediction in patients undergoing MPS have not been investigated. Methods and Results-We followed up 1652 consecutive patients who underwent stress MPS (32% exercise, 95% gated) for cardiac death for a mean of 2.15Ϯ0.8 years. MPS defects were defined with a summed stress score (normal summed stress score Ͻ4, abnormal summed stress scoreՆ4). Ischemia was defined as a summed stress score Ն4 plus a summed difference score Ն2, and scar was defined as a summed difference score Ͻ2 plus a summed stress score Ն4. Renal function was calculated with the Modified Diet in Renal Disease equation. CKD (estimated glomerular filtration rate Ͻ60 mL · min Ϫ1 · 1.73 m Ϫ2 ) was present in 36%. Cardiac death increased with worsening levels of perfusion defects across the entire spectrum of renal function. Presence of ischemia was independently predictive of cardiac death, all-cause mortality, and nonfatal myocardial infarction. Patients with normal MPS and CKD had higher unadjusted cardiac death event rates than those with no CKD and normal MPS (2.7% versus 0.8%, Pϭ0.001). Multivariate Cox proportional hazards models revealed that both perfusion defects (hazard ratio 1.90, 95% CI 1.47 to 2.46) and CKD (hazard ratio 1.96, 95% CI 1.29 to 2.95) were independent predictors of cardiac death after accounting for risk factors, left ventricular dysfunction, pharmacological stress, and symptom status. Both MPS and CKD had incremental power for cardiac death prediction over baseline risk factors and left ventricular dysfunction (global 2 207.5 versus 169.3, PϽ0.0001). Conclusions-MPS