High Sensitivity Troponin I as a Predictor of Survival in Heart Transplant Patients

Abstract

<h3>Purpose</h3> Although high sensitivity troponin I (hsTnI) levels are predictive of incident adverse cardiovascular outcomes in the general population and those with cardiovascular diseases, their prognostic significance in heart transplant (HT) patients is unknown. We hypothesized that hsTnI levels will also predict survival in heart transplant patients. <h3>Methods</h3> Heart transplant recipients enrolled in the Emory Cardiovascular Biobank had hsTnI levels measured (Abbott Laboratories) and were followed for a median of 10 years for all-cause mortality. Kaplan-Meier curves and log rank test were used to evaluate whether hsTnI levels (above/below median) predicted survival. Cox proportional hazard analysis was used to adjust for age, age at transplant, donor age, sex, race, smoking history, BMI, diabetes, hypertension, total cholesterol, low-density lipoprotein, and creatinine. <h3>Results</h3> In 156 HT recipients (mean age 54, 82% male, 53% chronic kidney disease), hsTnI levels were measured at a median 10 years after transplant [interquartile range (IQR) 4.0-14.8 years]. The median hsTnI level was 4.9 [IQR 2.9 - 9.9] pg/mL. 77 patients (49%) died at a median 6.2 years after hsTnI measurements. HsTnI levels were higher in patients who died compared to those alive (median 7.0 vs. 3.9 pg/mL, p<0.001). Both unadjusted (p=0.0002, figure) Kaplan-Meier analysis and adjusted Cox models (p=0.017) demonstrated worse survival in patients with higher hsTnI level. The adjusted hazard ratio was 2.64 (confidence interval 1.19-5.86) for those with hsTnI level greater than median (4.9 pg/ml) compared to those with less than median values. <h3>Conclusion</h3> HsTnI levels provide an independent estimate of survival in heart transplant recipients.