Prevalence of Different Gadolinium Enhancement Patterns in Patients After Heart Transplantation

Objectives: Transplant coronary artery disease (TCAD) limits long-term survival after heart transplantation (HTX). We hypothesized that contrast-enhanced magnetic resonance imaging (CE-MRI) detects chronic TCAD-related myocardial infarctions (MIs), even in patients with angiographically classified mild TCAD. Background: Coronary angiography underestimates the TCAD-degree, subsequently missing occluded small coronary arteries and resulting MI. CE-MRI as a noninvasive imaging technique identifies infarct-typical MI and myocardial fibrosis. Methods: CE-MRI (gadolinium: 0.2 mmol/kg/bw) was performed in 53 HTX patients on a 1.5-T MRI scanner (Philips, Best, the Netherlands). Infarct-typical CE-MRI areas were classified as: I = ≤25%, II = 25% to 50%, III = 50% to 75% and IV = ≥75%. Infarct-atypical forms were divided into diffuse, spotted, intramural, and infero-septal. Coronary angiography results were reviewed qualitatively with the TCAD score (TCAD I = mild evidence; II = 30% to 75%, III = ≥75% stenosis). Groups were compared with analysis of variance (statistically significant p values ≤0.05). Results: Infarct-typical CE-MRI was already present in TCAD I + II, increased significantly between groups (I = 23%, II = 33%, III = 84%, p < 0.05), and involved only single coronary territories in TCAD I but multiple vessels in TCAD II + III. Infarct-atypical CE-MRI was equally distributed across all TCAD stages (I = 50% vs. II = 58% vs. III = 42%, p = NS) without relation to a coronary territory. Patients with only infarct-atypical CE-MRI were associated with significantly better left ventricular function compared with patients with infarct-typical or combined CE-MRI patterns (ejection fraction = 66 ± 6% vs. 45 ± 16% or 60 ± 13%; end-diastolic volume = 139 ± 32 ml vs. 148 ± 27 ml or 164 ± 43 ml; end-systolic volume = 47 ± 15 ml vs. 81 ± 27 ml or 69 ± 38 ml, p ≤ 0.05). Conclusions: CE-MRI allows identification of silent MI in apparently event-free HTX patients and is able to disclose myocardial fibrosis already in patients with absent or mild angiographic TCAD. CE-MRI might be helpful to establish an earlier TCAD diagnosis and to intensify medical treatment. Future studies are necessary to test prognostic implications associated with CE-MRI patterns. [Copyright &y& Elsevier]