Treatment and outcomes of patients with recurrent myocardial infarction: A prospective observational cohort study

Background: Little is known about differences in therapies and outcomes of patients with first myocardial infarction (MI) or recurrent MI (reMI). This study aimed to evaluate the impact of prior MI on therapies and outcomes in patients who presented with ST-elevation MI (STEMI). Methods: All STEMI patients enrolled from 2002 to 2014 in the AMIS Plus registry were included. Outcome was analyzed using logistic multivariate regression. Results: From 19,665 STEMI patients, 2845 (14%) had reMI. These patients were older (69.5y vs. 64.2y; p<0.001), more frequently male, with more risk factors (hypertension, dyslipidemia), and more comorbidities. Patients with reMI presented 25min earlier than those with first MI, were more frequently in Killip class 3/4 (12% vs. 7%; p<0.001), and were less likely to receive guideline-recommended drug therapy: aspirin (93% vs. 97%; p<0.001), P2Y 12 inhibitors (76% vs. 83%; p<0.001), or statins (73% vs. 77%; p<0.001), or undergo primary percutaneous coronary intervention (77% vs. 87%; p<0.001). These patients developed more frequently cardiogenic shock (7% vs. 5%; p<0.001) and reinfarction (2% vs. 1%; p<0.001) during hospitalization, and had higher crude mortality (10% vs. 5%; p<0.001) than patients without prior MI. Prior MI was an independent predictor of in-hospital mortality in STEMI patients (OR 1.27; 95% CI 1.05-1.53; p<0.001). A subgroup (n=4486) was followed 1 year after discharge (3893 with first MI and 593 with reMI at initial hospitalization). Crude mortality was 2.9% for patients with first MI vs. 6.7% for those with reMI (OR 1.68, 95% CI 1.14-2.47; p=0.008). Conclusions: Although patients with reMI are high-risk patients, they were less likely to receive evidence-based treatment and had worse in-hospital and 1-year outcomes compared to patients with first MI. Short- and long-term management of patients with recurring MI should be improved.