Clinical characteristics and long-term prognosis of patients with premature acute myocardial infarction

Background Premature myocardial infarction (MI) is underrepresented in clinical trials, limiting understanding of its clinical characteristics and long-term prognosis. Purpose This study aimed to assess the distinct clinical features and long-term ischemic outcomes of patients with premature MI compared to non-premature MI. Methods We retrospectively analyzed the COREA-AMI registry, including MI patients who underwent percutaneous coronary intervention between 2001 and 2015. Premature MI was defined as age ≤ 45 years at presentation. The primary outcome was major adverse cardiac and cerebrovascular events (MACCE) and its components. Predictors of ischemic outcomes in premature MI were identified through Cox regression models, and clinical outcomes were compared between premature and non-premature MI. Fine-Gray subdistribution hazard regression and Cox regression with multiple imputation were performed as sensitivity analyses. Results Among 10,144 patients, 907 (8.9%) had premature MI. These patients had fewer comorbidities but higher LDL-C levels (≥160 mg/dL: 18.7% vs. 10.2%, P <.001) and lower rates of multivessel disease (34.3% vs. 55.3%, P <.001). In premature MI, chronic kidney disease and multivessel disease were independent predictors of MACCE, as well as recurrent MI and repeated revascularization. After adjustment, premature MI was associated with a higher risk of recurrent MI (HR 1.43, 95% CI 1.04–1.95, P =.026) but similar revascularization risk (HR 1.18, 95% CI 0.97–1.42, P =.101). Multivessel disease had a stronger impact on recurrent MI (P interaction =.002) and revascularization (P interaction =.020) in premature MI. Conclusions Premature MI patients had distinct clinical features and a higher risk of recurrent MI and but comparable revascularization risk. Multivessel disease was an important prognostic factor for ischemic outcomes in this population, warranting further investigations.