Comparison of Long-Term Clinical Outcomes in Patients Stratified by a Novel Acute Myocardial Infarction Risk Stratification (nARS) System

Background: As severity of acute myocardial infarction (AMI) varies widely, several risk stratifications for AMI have been reported. We have introduced a novel AMI risk stratification system linked to a rehabilitation program (novel AMI risk stratification; nARS), which stratified AMI patients into low (L)-, intermediate (I)-, and high (H)-risk groups. The purpose of this retrospective study was to compare the long-term clinical outcomes in patients with AMI among L-, I-, H-risk groups. Methods and Results: This study included 773 AMI patients, and assigned them into the L-risk group (n=332), the I-risk group (n=164), and the H-risk group (n=277). The primary endpoint was major cardiovascular events (MACE), defined as the composite of all-cause death, readmission for heart failure, non-fatal myocardial infarction, and target vessel revascularization after the discharge of index admission. The median follow-up duration was 686 days. MACE was most frequently observed in the H-risk group (39.4%), followed by the I-risk group (23.2%), and least in the L-risk group (19.9%) (P<0.001). The multivariate Cox hazard analysis revealed that the H-risk was significantly associated with MACE (HR 2.166, 95% CI 1.543-3.041, P<0.001) after controlling for multiple confounding factors. Conclusions: H-risk according to nARS was significantly associated with long-term adverse events after hospital discharge for patients with AMI. These results support the validity of nARS as a risk marker for long-term outcomes.