Impact of non-culprit lesion TCFA on adverse cardiovascular events in patients with diabetes mellitus who present with acute myocardial infarction

AIMS: Patients with acute myocardial infarction (AMI) and diabetes mellitus (DM) are at a higher risk of major adverse cardiovascular events (MACE) than those without DM. This study aimed to investigate whether thin-cap fibroatheroma (TCFA) in non-culprit lesions (NCLs) contributes to this increased risk in DM patients and whether NCL TCFA also adversely affects prognosis in non-DM patients. METHODS AND RESULTS: A total of 1312 AMI patients who underwent three-vessel optical coherence tomography (OCT) were analysed for NCL TCFA prevalence based on DM status. MACE was defined as cardiac death, non-fatal myocardial infarction (MI), or unplanned coronary revascularization. Multivariable models assessed the association between DM, TCFA, and NCL-MACE. DM patients (n = 311, 23.7%) had a significantly higher prevalence of NCL TCFA at both the patient (43.7% vs. 28.9%, P < 0.001) and lesion (15.3% vs. 10.5%, P < 0.001) levels. During a median follow-up of 4.1 years (IQR: 3.0-5.0 years), NCL-MACE occurred more frequently in DM patients (10.2% vs. 4.2%; HR: 2.10; 95% CI: 1.23-3.57), primarily driven by non-fatal MI (3.7% vs. 1.0%; HR: 3.33; 95% CI: 1.25-8.87). DM was independently associated with TCFA (adjusted OR: 1.61; 95% CI: 1.22-2.13), but not with NCL-MACE (adjusted HR: 1.66; 95% CI: 0.94-2.94) after adjusting for TCFA. In both DM and non-DM patients, NCL-MACE incidence was higher in those with TCFA than in those without. CONCLUSION: DM patients have a higher incidence of NCL-MACE after AMI, primarily due to increased NCL TCFA prevalence. In both DM and non-DM patients, NCL TCFA worsens long-term prognosis.