Diagnosis of acute myocardial infarction in patients with renal failure using high-sensitivity cardiac troponin T.

Aims: Diagnosing myocardial infarction (MI) in patients with chronic kidney disease (CKD) is difficult as they often have increased high-sensitivity cardiac troponin T (hs-cTnT) concentrations.

Methods and results: Observational US cohort study of emergency department patients undergoing hs-cTnT measurement. Cases with ≥1 hs-cTnT increase > 99th percentile were adjudicated following the Fourth Universal Definition of MI. Diagnostic performance of baseline and serial 2 h hs-cTnT thresholds for ruling-in acute MI was compared between those without and with CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2). The study cohort included 1992 patients, amongst whom 501 (25%) had CKD. There were 75 (15%) and 350 (70%) patients with CKD and 80 (5%) and 351 (24%) without CKD who had acute MI and myocardial injury. In CKD patients with baseline hs-cTnT thresholds of ≥52, >100, >200, or >300 ng/L, positive predictive values (PPVs) for MI were 36% (95% CI 28-45), 53% (95% CI 39-67), 73% (95% CI 50-89), and 80% (95% CI 44-98), and in those without CKD, 61% (95% CI 47-73), 69% (95% CI 49-85), 59% (95% CI 33-82), and 54% (95% CI 25-81). In CKD patients with a 2 h hs-cTnT delta of ≥10, >20, or >30 ng/L, PPVs were 66% (95% CI 51-79), 86% (95% CI 68-96), and 88% (95% CI 68-97), and in those without CKD, 64% (95% CI 50-76), 73% (95% CI 57-86), and 75% (95% CI 58-88).

Conclusion: Diagnostic performance of standard baseline and serial 2 h hs-cTnT thresholds to rule-in MI is suboptimal in CKD patients. It significantly improves when using higher baseline thresholds and delta values.