Diagnostic Performance of More Sensitive Cardiac Troponin Assays in Patients With Renal Dysfunction | Journal Scan

Study Questions:

What are the diagnostic performance and optimal cut-off levels of seven more sensitive cardiac troponin (cTn) assays for the early diagnosis of acute myocardial infarction (AMI) in patients with renal dysfunction?

Methods:

This was an analysis of data from the APACE (Advantageous Predictors of Acute Coronary Syndrome Evaluation) trial, an ongoing, prospective, international, multicenter study of patients with symptoms suggestive of AMI presenting to the emergency department. Patients eligible for this analysis had a creatinine value at presentation (and renal function was quantified with use of the Modification of Diet in Renal Disease Study equation) and cTn that was determined with one of seven more sensitive cTn assays (three sensitive, four high-sensitivity). The final diagnosis was centrally adjudicated by two independent cardiologists.

Results:

Among the 2,813 unselected patients in the total cohort, 447 (16%) had renal dysfunction. AMI was the adjudicated final diagnosis in 36% of patients with renal dysfunction as compared to 18% in patients with normal renal function (p < 0.001). Regarding the diagnostic accuracy of the more sensitive cTn assays in patients with impaired renal function, the receiver-operator-characteristic (ROC) curve (AUC) was only slightly lower in patients with renal dysfunction compared to those with normal renal function (AUC 0.87-0.89 in patients with renal dysfunction vs. 0.91-0.94 in patients with normal renal function; p < 0.05 for the four assays with the largest sample size/comparisons vs. patients with renal dysfunction). Optimal ROC-derived cTn cut-off levels in patients with renal dysfunction were significantly higher (1.9-3.4 times greater), compared to those in patients with normal renal function.

Conclusions:

More sensitive cTn assays maintain high diagnostic performance in patients with renal dysfunction. Assay-specific optimal cut-off levels are higher in patients with renal dysfunction.

Perspective:

This is an important analysis that specifically examines the diagnostic performance of more sensitive cTn assays in patients presenting with renal dysfunction and symptoms suggestive of AMI to the emergency department. As the authors opine, these findings should help dispel misunderstandings about the diagnostic utility of more sensitive cTn assays in patients with suspected AMI and renal dysfunction. Furthermore, clinical decision levels are assay-specific, and optimal cut-off levels should account for renal dysfunction.

Clinical Topics: Acute Coronary Syndromes

Keywords: Acute Coronary Syndrome, Area Under Curve, Creatinine, Early Diagnosis, Emergency Service, Hospital, Kidney Diseases, Myocardial Infarction, Prospective Studies, ROC Curve, Renal Insufficiency, Troponin


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