Clinical characteristics and outcomes of patients with myocardial infarction, myocardial injury and non-elevated troponins.
Am J Med. 2015 Nov 16;
Authors: Sarkisian L, Saaby L, Poulsen TS, Gerke O, Jangaard N, Hosbond S, Diederichsen AC, Thygesen K, Mickley H
BACKGROUND: Cardiac troponins have emerged as the preferred biomarkers for detecting myocardial necrosis and for diagnosing myocardial infarction. However, current cardiac troponin assays do not discriminate between ischemic or non-ischemic etiologies of myocardial cell death. Thus, when an increased troponin value is encountered in the absence of obvious myocardial ischemia, a careful search for other clinical conditions is crucial.
METHODS: In 2010-2011 we prospectively studied hospitalized patients who had cardiac troponin I measured on clinical indication. An acute myocardial infarction was diagnosed in cases of a cardiac troponin I rise and/or fall pattern with at least one value >30 ng/L (99th percentile) together with myocardial ischemia. Myocardial injury was defined as cardiac troponin I values >30 ng/L, but without signs or symptoms indicating overt cardiac ischemia. Patients with peak values ≤30 ng/L were classified as non-elevated cardiac troponin I. Follow-up was at least three years with all-cause mortality as the sole clinical endpoint.
RESULTS: Totally 3762 patients were included. Of these, 488 had acute myocardial infarction (13%), 1089 myocardial injury (29%) and 2185 non-elevated cardiac troponin I values (58%). Patients with myocardial injury frequently presented with dyspnea, were older and had more comorbidity than patients in the two other groups. During a median follow-up of 3.2 years, 1342 died. Mortality differed significantly between groups: 39% in myocardial infarction, 59% in myocardial injury and 23% in non-elevated cardiac troponin I patients (log-rank test; P<0.0001). No significant difference in mortality between type 2 myocardial infarction patients and those with myocardial injury was observed (63% and 59%, respectively).
CONCLUSIONS: Patients with myocardial injury are older and have more co-morbidity than those with acute myocardial infarction. Both groups exhibit a poorer prognosis than patients with non-elevated cardiac troponin I values. Notably, a very high long-term mortality is observed in type 2 myocardial infarction patients and those with myocardial injury.
PMID: 26593739 [PubMed - as supplied by publisher]