High sensitivity troponin I as a biomarker for cardiac allograft vasculopathy: Evaluation of diagnostic potential and clinical utility.

INTRODUCTION: Cardiac allograft vasculopathy (CAV) limits long-term survival in heart transplant (HTx) recipients. The use of biomarkers in CAV surveillance has been studied, but none are used in clinical practice. The predictive value of high-sensitivity troponin I (hsTnI) has not been extensively investigated in HTx recipients. METHODS: HTx patients undergoing surveillance coronary angiograms and enrolled in the Emory Cardiovascular Biobank had plasma hsTnI measured. CAV grade was assessed using ISHLT nomenclature. Multivariable cumulative link mixed modeling was performed to determine association between hsTnI level and CAV grade. Patients were followed for adverse outcomes over a median 10-year period. Kaplan-Meier survival analysis and Cox proportional hazard modeling were performed. RESULTS: Three hundred and seventy-two angiograms were analyzed in 156 patients at a median 8.9 years after transplant. hsTnI levels were positively correlated with concurrent CAV grade after adjustment for age, age at transplant, sex, BMI, hypertension, diabetes, hyperlipidemia, estimated glomerular filtration rate, and history of acute cellular rejection (p = .016). In an adjusted Cox proportional hazard model, initial hsTnI level above the median (4.9 pg/mL) remained a predictor of re-transplantation or death (hazard ratio 1.82; 95% confidence interval 1.16-2.90; p = .01). CONCLUSION: An elevated hsTnI level reflects severity of CAV and is associated with poor long-term outcomes in patients with HTx.