Long-Term Clinical Outcomes of High-Risk Plaques with Negative fractional flow reserve: the PECTUS-obs study.

BACKGROUND: High-risk plaques (HRP) in non-flow limiting, deferred non-culprit lesions have been associated with adverse short-term cardiovascular outcome after myocardial infarction (MI). However, the long-term prognostic implications remain largely unknown. AIMS: This study sought to evaluate the long-term association between HRP and clinical outcome after MI. METHODS: In the prospective, observational PECTUS-obs study, 438 patients with recent MI underwent optical coherence tomography (OCT) of all fractional flow reserve-negative non-culprit lesions. Patients were grouped according to the presence or absence of at least one OCT-identified HRP. The current study evaluates the final long-term outcome. The primary patient-level endpoint was defined as major adverse cardiovascular events (MACE), a composite of cardiac death, nonfatal MI or unplanned revascularization, excluding all periprocedural, indeterminate and all stent failure-related events. RESULTS: After a median follow-up of 1828 days (IQR1821-1842), presence of at least one HRP was associated with MACE (HR 1.87, 95% CI 1.11-3.14, p=0.017). Among the individual endpoint components, non-fatal MI (HR 4.07, 95% CI 1.23-13.52, p=0.013) and unplanned revascularization (HR 1.97, 95% CI 1.07-3.64, p=0.027) occurred more frequently in patients with at least one HRP. In an exploratory landmark analysis, the risk associated with presence of HRP was observed only during the first two years of follow-up. The lesion-level incidence of target lesion failure did not differ significantly between groups (HR 1.65, 95% CI 0.91-2.96, p=0.097). CONCLUSIONS: Non-flow limiting but high-risk non-culprit plaques are associated with adverse patient-level clinical outcome during long-term follow-up after MI, potentially with a more pronounced short-term risk. Clinical Trial Registration NCT03857971.