Plasma Levels of High-sensitivity Cardiac Troponin I and Histopathological Findings in Heart Transplant Patients: A Single-center Cross-sectional Study

Introduction: This study aimed to evaluate the association between plasma levels of high-sensitivity cardiac troponin I (cTnI) in heart transplant patients and the grading of graft rejection. Methods: In a cross-sectional study, 92 biopsy samples from the patients who had undergone heart transplantation during 2022, at Rajaie Cardiovascular Medical and Research Center, the largest referral center in Tehran, Iran, were evaluated for heart transplant rejection. Transplant rejection grades, high-sensitivity troponin I plasma levels, and the relationship between them were assessed statistically. Results: Forty-two patients (mean age 37 ± 9.6 years, 26 (62%) male) were assessed. The mean transplant age was 3 ± 1.8 years. In terms of graft rejection, 30 (33%) biopsies showed Grade 1R and 4 (4%) showed Grade 2R. Quilty effect was observed in 43 (47%). The median (Q1–Q3) of the cTnI was 0.02 (0.02–0.75) and 43 (47%) had high troponin level (>0.03 ng/mL). A positive association was observed between high cTnI and rejection (P = 0.025). Conclusion: The association between the troponin level and rejection grade suggested the considerable myocardial injury during the rejection process.