Implication of myocardial perfusion abnormalities on clinical outcomes in patients undergoing percutaneous coronary intervention for chronic total occlusions

Introduction Myocardial Perfusion Imaging (MPI) is useful in the evaluation of myocardial ischemia in patients with Chronic Total Occlusion (CTO). However, prognostic implications of percutaneous coronary intervention (PCI) of CTO according to myocardial ischemia on MPI remain unclear. Purpose To evaluate outcomes in patients undergoing CTO-PCI stratified by moderate-severe ischemia on MPI. Method Patients from the Western Danish Heart Registry (2017–2022) who underwent CTO-PCI and nuclear MPI ≤ 6 months prior to the procedure were included and stratified based on the presence of moderate-severe reversible ischemia (≥ 10% left ventricle involvement) on MPI. Primary endpoints were all-cause mortality and major adverse cardio- and cerebrovascular events (MACCE) defined as myocardial infarction, cardiovascular death, stroke, and hospitalization for heart failure or angina. Secondary endpoints included individual MACCE components. Outcomes were analyzed using cumulative incidence and Kaplan-Meier curves and compared using multivariable Cox regression at 90-day and 5-year follow-up. Results Among 319 patients, 208 (69.9%) had moderate-severe ischemia. Patient characteristics were comparable between groups. At 5 years, overall survival rates were similar between patients with and without moderate-severe ischemia (86.34% vs. 89.54%; unadjusted HR = 0.73 [95% CI 0.35−1.55], p = 0.41; adjusted HR = 0.89 [95% CI 0.41−1.93], p = 0.77). The cumulative incidence of MACCE was 9.67% vs. 12.69% at 90 days, and 29.69% vs. 36.22% at 5 years for each group, respectively, with no difference at either time point (90 days: Unadjusted HR = 1.34 [95% CI 0.68−2.66], p = 0.40; adjusted HR = 1.31 [95% CI 0.65−2.66], p = 0.45. 5 years: Unadjusted HR = 1.25 [95% CI 0.8−1.97], p = 0.32; adjusted HR = 1.36 [95% CI 0.84−2.2], p = 0.21). No difference was found between groups in the risk of hospitalization for myocardial infarction at 5 years (unadjusted HR =1.34 [95% CI 0.49−3.72], p = 0.57; adjusted HR = 1.34 [95% CI 0.45−4.01], p = 0.60), or hospitalization for heart failure at 90 days (unadjusted HR = 1.9 [95% CI 0.71−5.07], p = 0.20; adjusted HR = 2.22 [95% CI 0.8−6.15], p = 0.13) or 5 years (unadjusted HR = 1.49 [95% CI 0.73−3.02], p = 0.27; adjusted HR = 1.57 [95% CI 0.75−3.28], p = 0.23). The cumulative incidence of hospitalization for angina pectoris was 4.87% vs. 6.31% at 90 days, and 12.11% vs. 23.40% at 5 years, for each group, respectively, with similar risk at 90 days (unadjusted HR = 1.32 [95% CI 0.5−3.48], p = 0.57; adjusted HR = 1.31 [95% CI 0.46-3.7], p = 0.61), and significantly increased risk at 5 years for patients without moderate-severe ischemia (unadjusted HR = 1.83 [95% CI 1−3.34], p = 0.049; adjusted HR = 2.12 [95% CI 1.1−4.09], p = 0.024). Conclusion Moderate-severe ischemia on MPI was not associated with differences in mortality or MACCE after CTO-PCI but was associated with a lower long-term risk of hospitalization for angina pectoris.