Risk stratification with pre-operative myocardial perfusion imaging

Myocardial perfusion imaging (MPI) is frequently used to improve cardiac risk prediction in patients undergoing non-cardiac surgery. However, the data supporting this practice is derived from single center studies and predates current therapy for coronary artery disease (CAD). We evaluated the association between pre-operative testing indication and outcomes as well as predictors of death or myocardial infarction (MI) in these patients.

We include patients from the international, multicenter REFINE-SPECT registry (13 sites). Based on referral indication, patients were classified as pre-operative testing indications and non-pre-operative testing. We evaluated the associations between pre-operative testing and incidence of death or MI. We then evaluated associations with death or MI in patients referred for pre-operative testing compared to other patients.

In total, 32,711 patients were included with pre-operative testing as the indication in 2,173(6.6%) patients. Patients referred for pre-operative testing were more likely to experience death or MI (annualized rate 4.4% vs 1.6%, p < 0.001). In patients referred for pre-operative testing, stress, rest, and ischemic total perfusion deficit were associated with death or MI. Rest total perfusion deficit (adjusted hazard ratio [HR] 1.25, 95% confidence interval [CI] 1.07 - 1.45) was independently associated with death or MI, but pharmacologic stress testing was not (adjusted HR 0.88, 95% CI 0.70 - 1.12).

Patients undergoing pre-operative SPECT MPI are at increased cardiovascular risk which may reflect selection bias or unmeasured confounders. Resting perfusion abnormalities may identify patients at higher risk, potentially helping guide peri-operative care.