Utility of High Sensitivity Troponin I to Monitor Cardiac Allograft Vasculopathy Progression

Abstract

<h3>Purpose</h3> To determine whether high sensitivity troponin I (hsTnI) levels are associated with progression of cardiac allograft vasculopathy (CAV). <h3>Methods</h3> Heart transplant recipients undergoing surveillance coronary angiograms for CAV had hsTnI levels measured (Abbott Laboratories). CAV was graded according to ISHLT classification. CAV progression was defined as an increase in CAV grade compared to the prior angiogram. The associations between baseline (BL) hsTnI, hsTnI at serial evaluation, and the change in hsTnI levels between angiograms versus CAV progression were compared using Kruskal-Wallis test. Age, age at transplant, sex, BMI, race, smoking, diabetes, hypertension, cholesterol, and creatinine were assessed as potential covariates. <h3>Results</h3> In 136 patients (mean age 54, 80% male), baseline angiograms and 173 serial angiograms were evaluated, and 68 (39%) identified CAV progression. Baseline testing occurred 11.2 years after transplant (interquartile range 5.9 - 15.9 years) and the median time between evaluations was 3.0 years. The BL hsTnI was similar (median 4.60 pg/mL in progressors, 4.35 in non-progressors). In patients with progression, the median hsTnI level was 5.55 pg/mL compared to 4.35 pg/mL in patients without progression (p=0.011). The change in hsTnI level was also greater in progressors compared to non-progressors (1.30 vs. 0.25 pg/mL, p=0.015). Creatinine did not differ significantly between groups (median 1.5 vs 1.4 mg/dL). In a multivariate analysis including smoking history, BMI, total cholesterol, BL hsTnI, hsTnI, and change in hsTnI, CAV progression was associated with smoking history, BMI, and hsTnI (p=0.042), but associations with BL hsTnI (p=0.053) and change in hsTnI (p=0.076) were not statistically significant. <h3>Conclusion</h3> Serial hsTnI measurements may be useful in transplant recipients to identify CAV progression. Further study is needed to determine if serial hsTnI measurements can be used to obviate the need for routine angiography to detect CAV progression.