High thrombotic risk increases adverse clinical events up to 5 years after acute myocardial infarction. A nationwide retrospective cohort study.

The risk of recurrent events among survivors of acute myocardial infarction (AMI) is understudied. The aim of this analysis was to investigate the role of residual high thrombotic risk (HTR) as a predictor of recurrent in-hospital events after AMI. This retrospective cohort study included 186,646 patients admitted with AMI from 2009 to 2010 in all Italian hospitals who were alive 30 days after the index event. HTR was defined as at least one of the following in the 5 years preceding AMI: previous myocardial infarction, ischemic stroke/other vascular disease, type 2 diabetes mellitus, renal failure. Risk adjustment was performed in all multivariate survival analyses. Rates of major cardiac and cerebrovascular events (MACCE) within the following 5 years were calculated in both patients without fatal readmissions at 30 days and in those free from in-hospital MACCE at 1 year from the index hospitalization. The overall 5-year risk of MACCE was higher in patients with HTR than in those without HTR, in both survivors at 30 days [hazard ratio (HR), 1.49; 95% confidence interval (CI), 1.45-1.52; p<0.0001] and in those free from MACCE at 1 year (HR, 1.46; 95% CI, 1.41-1.51; p<0.0001). The risk of recurrent MACCE increased in the first 18 months after AMI (HR, 1.49) and then remained stable over 5 years. The risk of MACCE after an AMI endures over 5 years in patients with HTR. This is also true for patients who did not have any new cardiovascular event in the first year after an AMI. All patients with HTR should be identified and addressed to intensive preventive care strategies.