Culprit-Plaque Morphology and Residual SYNTAX Score Predict Cardiovascular Risk in Acute Myocardial Infarction: An Optical Coherence Tomography Study

Aims: Culprit-plaque morphology [plaque rupture (PR) and plaque erosion (PE)] and high-risk plaques (HRP) identified by optical coherence tomography (OCT) and residual SYNTAX score (rSS) have been reported to influence clinical outcomes. Thus, in this study, we aimed to investigate the prognostic implication of culprit-plaque morphology and rSS for major adverse cardiovascular events (MACE) in patients with ST-segment elevation myocardial infarction (STEMI). Methods: Based on plaque morphology and rSS, 274 STEMI patients were divided into 4 groups: PE/low-rSS (n=61), PE/high-rSS (n=58), PR/low-rSS (n=55), and PR/high-rSS (n=100). According to HRP and rSS, patients were stratified to non-HRP/low-rSS (n=97), non-HRP/high-rSS (n=109), HRP/low-rSS (n=19), and HRP/high-rSS (n=49). MACE was defined as the composite of all-cause death, recurrence of myocardial infarction, stroke, and unplanned revascularization of any coronary artery. Results: During the follow-up of 2.2 years, 47 (17.2%) MACE were observed. Patients with PR/high-rSS and HRP/high-rSS presented lower survival probability on revascularization and MACE. In fully adjusted analyses, PR/high-rSS group presented higher MACE risk than PE/low-rSS (HR: 4.80, 95% CI: 1.43–16.11,P=0.025). Patients with non-HRP/high-rSS (HR: 2.90, 95% CI: 1.01–8.38,P=0.049) and HRP/high-rSS (HR: 8.67, 95% CI: 2.67–28.21,P＜0.001) presented higher risk of cardiac events than non-HRP/low-rSS. Adding rSS and HRP to the risk prediction model increased the C-statistic to 0.797 (95% CI: 0.737–0.857), with ΔC-statistic of 0.066 (P=0.002) and the NRI (46.0%, 95% CI: 20.5–56.8%,P＜0.001) and IDI (8.7%, 95% CI: 3.6–18.2%,P＜0.001). Conclusion: High-risk plaques in combination with rSS enhanced the predictive ability for MACE, indicating culprit-plaque features and residual atherosclerosis burden should be taken into account in risk stratification of STEMI patients.