Abstract 17968: Correlation of Cardiac MRI Findings and Endomyocardial Biopsy Results in Patients Undergoing Screening for Heart Transplant Rejection
Introduction: Endomyocardial biopsy (EMB) is the current gold standard to screen for heart transplant rejection, but it has important risks and limitations. Cardiovascular MRI (CMR) is a non-invasive imaging modality that could be useful in diagnosing heart transplant rejection. We compared the diagnostic accuracy of CMR to EMB for the diagnosis of heart transplant rejection. We also compared both CMR and EMB with the clinical diagnosis of heart transplant rejection.
Methods: We recruited adult heart transplant recipients undergoing routine and clinically indicated EMB. CMR scans were performed within 24 hours of EMB, before initiation of any new anti-rejection therapy, and blinded to EMB results. CMR protocols evaluated myocardial edema, myocardial scar, ventricular volumes, as well as ventricular systolic and diastolic function. Multivariable logistic regression and linear classifiers to maximize Akaike Information Criterion were employed to create CMR diagnostic criteria for rejection. Positive EMB was defined as > 2R cellular rejection or Antibody Mediated Rejection. Clinical Rejection was defined as an increase in anti-rejection therapy to treat acute rejection in response to a clinical evaluation and EMB.
Results: sixty one participants were recruited (55% male, mean age 51), providing 73 comparisons between CMR and EMB for the diagnosis of heart transplant rejection. Multivariable logistic regression identified myocardial edema (T2 relaxation time) and right ventricular end diastolic volume index (RVEDVI) as independent predictors of positive EMB (sensitivity 93%, specificity 78%, positive predictive value 52%, and negative predictive valve 98%). CMR was more sensitive than EMB at predicting Clinical Rejection (sensitivity 67% vs 58%).
Conclusion: CMR has high sensitivity and high negative predictive value in predicting biopsy positive heart transplant rejection and may be useful as an initial screening test prior to routine EMB. CMR also has better agreement with the clinical diagnosis of heart transplant rejection and could be helpful in cases of biopsy negative rejection.
- © 2013 by American Heart Association, Inc.