ABSTRACT
Acute myocardial infarction (AMI) is defined as a dynamic change in cardiac troponin (cTn) with at least one cTn value exceeding the 99 th percentile of a reference population in combination with typical clinical symptoms. In hemodialysis (HD) patients, a broad range of cTn concentrations is found, partially due to patient-specific comorbidities. Therefore, the 99 th percentile cannot be used in HD patients and decision algorithms to diagnose AMI should be based on temporal variations of troponin. In this study, relative and absolute variations of cTn in a large population of asymptomatic hemodialysis patients were established during a period of 15 months. Patients were stratified according to their history of coronary artery disease (CAD). An intra-individual long term variation of 23% for cTroponin I (cTnI) and 12% for cTroponin T (cTnT) was found for patients without a history of CAD. The corresponding reference change values (RCVs) were 69% and 39% respectively. For patients with a history of CAD this variation was 29% for cTnI and 10% for cTnT, with RCVs of 86% and 35% respectively. During follow up, 27 HD patients developed an acute myocardial infarction (AMI). During these events, irrespective of CAD history, cTnI increased>172% and cTnT increased>97% above baseline cTn as measured during clinically stable periods three months separate to the event. Therefore, if a HD patient has symptoms of an acute event and a cTn increase that exceeds the RCVs described here, AMI may be suspected. If the troponin increase exceeds 172% for cTnI or 97% for cTnT, AMI is likely.
