ST- Elevation Myocardial Infarction in Patients under 40 Years Old: Observational Study of more than a Decade

Background: There are little data regarding the unique features of acute myocardial infarction in young patients. We aimed to examine the clinical characteristics and clinical outcomes of young patients admitted with ST segment elevation myocardial infarction (STEMI).
Methods: A retrospective analysis of patients with STEMI admitted during 2001-2014 who underwent primary percutaneous coronary intervention within 12 hours from symptoms onset.
Results: Out of 2578 patients with STEMI, 3.7% (n=95) were 40 years old or younger. Young patients were more likely to be male (p=0.04), smokers (p=0.02) and with a family history of cardiovascular disease (p<0.0001), but less likely to have traditional risk factors including hypertension, hypercholesterolemia and diabetes mellitus. Clinical presentation in young patients was milder, with lower rates of cardiogenic shock (p=0.04) or higher Killip (III/IV) class (p=0.07). Anterior wall STEMI was more common in young patients (p=0.02), without a significant difference in left ventricular systolic function. Angiography demonstrated a single vessel disease in 74% of young patients vs. 38% in older patients (p<0.0001). Angiographic outcomes were comparable between both groups. At 1 year, young patients had similar rates of death (2.2% vs. 5.7%, p=0.1), MI (7.0% vs. 5.6%, p=0.5), stent thrombosis (0% vs. 2.7%, p=0.1), target vessel revascularization (9.3% vs. 11.8%, p=0.5) and coronary artery bypass graft surgery (2.3% vs. 4.2%, p=0.4).
Conclusions: STEMI in young patients is a distinct clinical entity associated with different risk factors and clinical presentation. The 1-year rate of major adverse cardiac events of young patients admitted with STEMI is similar to the rate of older patients.