Objectives: Hypertrophic cardiomyopathy (HCM) entails thickening of the myocardium and an increased risk of ischaemia. However, the prognosis of patients with HCM with acute myocardial infarction (AMI) is incompletely understood.
Methods: Medical information was retrieved from the Taiwan National Health Insurance Research Database in 1997-2011. The exclusion criteria were patients <18 years old, and history of AMI, coronary intervention, aortic valve disease, disease of the pericardium, heart surgery, device implantation, venous thromboembolism, cardiac transplant, congenital heart disease and end-stage renal disease on dialysis. Patients with HCM with AMI were compared with propensity score (PS)-matched patients with AMI without HCM. The primary endpoints were in-hospital and 1-year cardiovascular events.
Results: In total, 201 166 patients were admitted for AMI. There were 177 058 patients with new-onset AMI, 257 with HCM and 176 801 without HCM after exclusion criteria. Using 1:4 PS matching, the study population consisted of patients with AMI, 257 with HCM and 1028 without HCM. Patients with AMI with HCM received significantly less coronary intervention (OR=0.46; 95% CI 0.32 to 0.65; p<0.001), coronary intervention with stenting (OR=0.33; 95% CI 0.20 to 0.57; p<0.001) and coronary artery bypass graft surgery (OR=0.22; 95% CI 0.05 to 0.90; p=0.036), and fewer episodes of shock (OR=0.64; 95% CI 0.48 to 0.86; p=0.003) and in-hospital death (OR=0.46; 95% CI 0.30 to 0.70; p<0.001), compared with patients with AMI without HCM. Specifically, for patients with HCM with AMI, AMI occurred predominantly (82.5%) in the form of ischaemia without requiring coronary stenting. Patients with AMI with HCM had significantly better survival than patients without HCM (HR=0.66; 95% CI 0.51 to 0.85; p=0.001) during the 1-year follow-up.
Conclusions: This is the first PS-matched study to compare the prognosis of patients with AMI with and without HCM. Compared with patients with AMI without HCM, patients with HCM had significantly better in-hospital and within 1-year outcomes.
Keywords: acute myocardial infarction; hypertrophic cardiomyopathy; outcome.
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