Impact of Changing Definitions for Myocardial Infarction: A Report from the AMIS Registry
Abstract
Background
To assess the impact of the new definitions of myocardial infarction, we retrospectively analyzed 9190 patients from 63 hospitals with reported peak troponin values included between 2001 and 2007 in the Swiss AMIS (Acute Myocardial Infarction in Switzerland) Plus registry.
Methods
Patients were classified as belonging to the “classic” myocardial infarction group (peak total CK or CK-MB above the upper limit of normal, or troponin T [TnT] >0.1 μg/L or troponin I [TnI] >0.1-0.8 μg/L [depending on the assay]) or “new” myocardial infarction group (TnT >0.01 μg/L or TnI >0.01-0.07 μg/L).
Results
There were 489 patients in the “new” group who were similar to the 8701 “classic” patients in terms of age, sex, and prevalence of both diabetes and renal failure, but more frequently had a history of prior coronary artery disease, hypertension, and hyperlipidemia. At admission, they less frequently had ST elevation on their electrocardiogram, were more frequently in Killip class I, and received less primary percutaneous coronary intervention. Hospital mortality was 3.5% in the “new” and 6.7% in the “classic” myocardial infarction group (P=.004). In a subset of patients with a longer follow-up, mortality at 3 and 12 months was 1% and 5.6%, respectively, for “new” and 1.6% and 4%, respectively, for “classic” myocardial infarction (NS).
Conclusions
Patients with minimal elevation of serum troponin have smaller infarctions, less aggressive treatment, fewer early complications, and a better early prognosis than patients with higher serum biomarker levels. After discharge, however, their prognosis currently appears no different from that of patients with a “classic” myocardial infarction event.
gCardio-Vascular Center Zurich, Klinik im Park, Zurich, Switzerland
Requests for reprints should be addressed to Philip Urban, MD, Cardiovascular Department, La Tour Hospital, 1 Av JD Maillard, Geneva 1217, Switzerland
Funding: The AMIS Plus registry is funded by unrestricted grants from the Swiss Heart Foundation and from Abbott, Astra-Zeneca, Biotronik, Boehringer Ingelheim, Boston Scientific, Bristol-Myers Squibb, Essex/MSD, GlaxoSmithKline, Guidant, INVATEC, Johnson & Johnson – Cordis Division, A Menarini, Medtronic, Mepha Pharma, Merck Sharp & Dohme-Chibret, Novartis, Pfizer, Sanofi-Aventis, Schering, Servier, SPSS, St. Jude Medical, and Takeda Pharma, all in Switzerland.
ABSTRACT
