[Treatment of functionally nonsignificant vulnerable plaques in multivessel STEMI: design of the VULNERABLE trial].

Introduction And Objectives: The optimal treatment of nonculprit angiographic intermediate lesions (diameter stenosis 40%-69%) in patients with ST-segment elevation myocardial infarction (STEMI) is still unknown. Lesions with fractional flow reserve (FFR) ≤ 0.80 are indicative of ischemia and benefit from revascularization. However, lesions with FFR > 0.80 and optical coherence tomography (OCT) findings of vulnerability have been hypothesized to cause adverse events during follow-up. The study aims to compare the efficacy of a preventive treatment with stent implantation plus optimal medical therapy vs optimal medical therapy alone for nonculprit intermediate lesions with FFR > 0.80 and OCT findings of plaque vulnerability in STEMI patients at 4 years of follow-up.

Methods: This parallel-group, multicenter, controlled, single-blind, and 1:1 randomized trial will enroll a total of 600 STEMI patients with ≥ 1 intermediate nonculprit lesions with FFR > 0.80 and OCT findings of plaque vulnerability. The primary endpoint is target vessel failure, defined as the composite of cardiac death, target vessel myocardial infarction, or target vessel revascularization. The study will include a parallel registry of patients with FFR > 0.80 but without OCT findings of vulnerability. Vulnerable plaques are defined as lipid-rich fibroathermas with plaque burden ≥ 70% and a thin fibrous cap (≤ 80 mm).

Results: The VULNERABLE trial will reveal the role of preventive treatment with stent implantation for nonculprit and functionally nonsignificant vulnerable plaques in STEMI patients.

Conclusions: This is the first randomized trial of OCT-guided treatment of vulnerables plaques. Registered at ClinicalTrials.gov (NCT05599061).