High‐Sensitivity Troponin I in Hospitalized and Ambulatory Patients With Heart Failure With Preserved Ejection Fraction: Insights From the Heart Failure Clinical Research Network

BACKGROUND: We sought to study the prevalence of high‐sensitivity troponin and its association with cardiac structure and outcomes in ambulatory and hospitalized patients with heart failure with a preserved ejection fraction (HFpEF). METHODS AND RESULTS: A post hoc analysis utilized data from HFpEF patients: DOSE (Diuretic Optimization Strategies Evaluation) and CARRESS‐HF (Cardiorenal Rescue Study in Acute Decompensated Heart Failure) enrolled patients hospitalized with acute HFpEF, and RELAX (Phosphodiesterase‐5 Inhibition to Improve Clinical Status and Exercise Capacity in Heart Failure With Preserved Ejection Fraction) enrolled ambulatory patients with HFpEF. High‐sensitivity troponin I (hs‐TnI) was measured in hospitalized patients at baseline, at 72 to 96 hours, on day 7, and on day 60. In ambulatory patients hs‐TnI was measured at baseline and at week 24. In the ambulatory cohort, correlations between hs‐TnI and cardiac structure and function were assessed. The association between hs‐TnI and a 60‐day composite of emergency room visits, readmissions, and death was assessed for hospitalized patients using multivariable Cox proportional hazard models. The study population included 139 hospitalized and 212 ambulatory patients with HFpEF and hs‐TnI measured at baseline. The median (25th, 75th percentiles) baseline troponin was 17.6 (11.1, 41.0) ng/L in hospitalized patients and 9.5 (5.3, 19.7) ng/L in ambulatory patients (P<0.001). The prevalence of elevated hs‐TnI (>99% percentile upper reference limit was 86% in hospitalized patients and 53% among ambulatory patients, with stable elevation in ambulatory patients during follow‐up. HFpEF patients with a hs‐TnI above the median were older with worse left ventricular hypertrophy and diastolic dysfunction. Continuously valued hs‐TnI (per doubling) was associated with increased risk of composite end point (adjusted hazard ratio 1.20, 95% confidence interval 1.00‐1.43; P=0.042). CONCLUSIONS: Hs‐TnI is commonly elevated among both hospitalized and ambulatory patients with HFpEF. Increased hs‐TnI levels are associated with worse cardiac structure and increased risk of adverse events.