Mortality in Stable Coronary Disease in Patients With Intermediate- or High-Risk Myocardial Perfusion Imaging

The management of patients with stable coronary disease and intermediate- or high-risk features on single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) continues to be controversial as to whether they should be treated with an initial invasive strategy (catheterization and revascularization when feasible) or medical therapy alone to improve mortality. We performed a retrospective observational study of 1,946 patients with intermediate- or high-risk SPECT MPI scans performed over a 6-year period (from 2014 to 2019). Each patient was followed from the time of SPECT MPI to 16 months after the last patient was enrolled. The primary end point was all-cause mortality and the secondary end point cardiovascular mortality. Of the eligible 1,697 patients, 1,144 had an intermediate-risk scan, 553 a high-risk scan, 915 had medical therapy alone, and 782 went on an initial invasive strategy. All patients were divided into the following three groups: combined SPECT MPI (both intermediate- and high-risk), high-risk SPECT MPI, and intermediate-risk SPECT MPI groups. After propensity score matching, there was a statistically significant difference in cardiovascular death (5.9% vs 2.7%; p = 0.038) in the medical therapy cohort compared with initial invasive cohort in the combined SPECT MPI group, but no difference in all-cause death (15.7% vs 13%; p = 0.318). On subgroup analysis, in intermediate-risk SPECT MPI group, there was no significant difference in either all-cause death (13.8 vs 11.7%; p = 0.583) or cardiac death (5.4% vs 2.5%; p = 0.16) in conservative cohort compared with invasive strategy cohort. In high-risk SPECT MPI group, conservative therapy cohort had higher cardiac death (11.7% vs 2.5%; p = 0.002) compared with initial invasive strategy cohort, but there was no significant difference in all-cause death (24.5% vs 15.3%; p = 0.052). In conclusion, this study supports that patients with intermediate- or high-risk SPECT MPI scans when considered together or only with high-risk features, derive a cardiovascular mortality benefit with an initial invasive strategy. Patients who had undergone intermediate-risk SPECT MPI had similar outcomes with either medical therapy alone or initial invasive evaluation.