P1578Outcomes in patients with renal impairment and myocardial injury or infarction identified by high-sensitivity cardiac troponin testing: a secondary analysis of the High-STEACS trial

Abstract

Abstract Background Patients with renal impairment are at increased risk of myocardial infarction (MI), but the interpretation of cardiac troponin is challenging in this setting. The use of high-sensitivity cardiac troponin (hs-cTn) assays increases the detection of myocardial injury, yet may contribute to uncertainty in the diagnosis of MI in those with renal impairment. Purpose To describe the diagnosis and outcomes of patients with myocardial injury or infarction identified using a hs-cTnI assay, stratified by renal function. Methods In a pre-specified secondary analysis of a stepped-wedge cluster-randomised controlled trial, we identified consecutive patients with a hs-cTnI concentration greater than the sex-specific 99th centile between June 2013 and March 2016. The diagnoses of type 1 or type 2 MI were adjudicated and classified according to the 4th Universal Definition of Myocardial Infarction. Renal impairment was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73m2.The primary outcome of type 1 or type 4b MI or cardiovascular death was compared in patients with and without renal impairment at 1 year. Results A measure of renal function was available in 47,334 (98.0%) patients, of whom 7,933 (16.8%) had renal impairment (mean age 76±12 years; 54% female). Plasma hs-cTnI concentrations were >99th centile in 47.9% (3,800/7,933) of patients with renal impairment and 16.3% (6,439/39,401) of patients with normal renal function. In those with and without renal impairment, the adjudicated diagnosis was type 1 MI in 35.2% (1,336/3,800) and 55.8% (3,596/6,439) of patients, and type 2 MI in 12.6% (480/3,800) and 9.7% (626/6,439) of patients, respectively (P<0.001 for both). In patients with hs-cTnI concentrations >99th centile, the primary outcome occurred in 24.9% (945/3,800) of patients with renal impairment, compared to 12.1% (779/6,439) of patients with normal renal function (P<0.001). In patients with type 1 MI, the primary outcome occurred in 32.6% (436/1,336) of those with renal impairment and 11.7% (419/3,596) of those without (P<0.001). In patients with type 2 MI, the primary outcome occurred in 20.4% (98/480) and 9.9% (62/626) of patients with and without renal impairment, respectively (P<0.001). Conclusion Almost half of all patients with suspected acute coronary syndrome and renal impairment have hs-cTnI concentrations greater than the sex-specific 99th centile. Whilst only one in three had a diagnosis of type 1 MI, an elevated troponin concentration was associated with a poorer prognosis in those with concomitant renal impairment compared to those without, irrespective of the index diagnosis. Acknowledgement/Funding British Heart Foundation