Prevalence of different gadolinium enhancement patterns in patients after heart transplantation.
OBJECTIVE
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=<or=25%, II=25% to 50%, III=50% to 75% and IV=>or=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=>or=75% stenosis). Groups were compared with analysis of variance (statistically significant p values<or=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<or=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.
Steen
Henning
H
Abteilung Innere Medizin III, Medizinische Klinik, Universitätsklinikum Heidelberg, Heidelberg, Germany.
Merten
Constanze
C
Refle
Sonja
S
Klingenberg
Roland
R
Dengler
Thomas
T
Giannitsis
Evangelos
E
Katus
Hugo A
HA
D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005355:Fibrosis; D005682:Gadolinium; D006334:Heart Function Tests; D016027:Heart Transplantation / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology; D009206:Myocardium / Q000473:pathology
D005682:Gadolinium