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

Abstract 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.