Optimal Cut-Off Levels of More Sensitive Cardiac Troponin Assays for the Early Diagnosis of Myocardial Infarction in Patients with Renal Dysfunction
Background—It is unknown, whether more sensitive cardiac troponin (cTn) assays maintain their clinical utility in patients with renal dysfunction. Moreover, their optimal cut-off levels in this vulnerable patient population have not been defined previously.
Methods and Results—In this multicenter study we examined the clinical utility of seven more sensitive cTn-assays (three sensitive, four high-sensitivity cTn-assays) in patients presenting with symptoms suggestive of acute myocardial infarction (AMI). Among 2813 unselected patients, 447 (16%) had renal dysfunction (defined as estimated MDRD-GFR <60ml/min/1.73m2). The final diagnosis was centrally adjudicated by two independent cardiologists using all available information including coronary angiography and serial levels of high-sensitivity cTnT. AMI was the final diagnosis in 36% of all patients with renal dysfunction. Among patients with renal dysfunction and elevated baseline cTn-levels (≥99th percentile), AMI was the most common diagnosis for all assays (range 45-80%). In patients with renal dysfunction diagnostic accuracy at presentation, quantified by the area under the receiver-operator-characteristic (ROC) curve (AUC), was 0.87-0.89 with no significant differences between the seven more sensitive cTn-assays and further increased to 0.91-0.95 at 3h. Overall, AUC in patients with renal dysfunction was only slightly lower than in patients with normal renal function. Optimal ROC-derived cTn-cut-off-levels in patients with renal dysfunction were significantly higher versus patients with normal renal function (factor 1.9-3.4).
Conclusions—More sensitive cTn-assays maintain high diagnostic accuracy also in patients with renal dysfunction. To ensure best possible clinical use, assay-specific optimal cut-off levels, which are higher in patients with renal dysfunction, should be considered.
Clinical Trial Registration Information—www.clinicaltrials.gov. Identifier, NCT00470587.
- Received November 11, 2014.
- Revision received February 25, 2015.
- Accepted March 27, 2015.
Circulation is published on behalf of the American Heart Association, Inc., by Wolters Kluwer. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial-NoDervis License (http://creativecommons.org/licenses/by-nc-nd/3.0/), which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is noncommercial, and no modifications or adaptations are made.