Cardiac MRI T2* in Liver Transplant Candidates: Application and Performance of a Novel Imaging Technique to Identify Patients at Risk for Poor Posttransplant Cardiac Outcomes

Abstract

Background. In end-stage liver disease, alterations in iron metabolism can lead to iron overload and development of iron overload cardiomyopathy. In liver transplant candidates, evaluation for cardiac iron overload and dysfunction can help to identify candidates at increased risk for peritransplant morbidity and mortality, though recommendations for pretransplant evaluation of cardiac iron overload are not standardized. Cardiac Magnetic Resonance Imaging T2* (CMRI-T2*) is a validated method to quantify cardiac iron deposition, with normal T2* value of 20 ms or greater. In this study, we sought to identify the incidence and predictors of iron overload by CMRI-T2* and to evaluate the impact of cardiac and iron overload on morbidity and mortality after liver transplantation. Methods. In this retrospective single-center cohort study, all liver transplant candidates who underwent a pretransplant CMRI-T2* between January 1, 2008, and June 30, 2016, were included to analyze the association between clinical characteristics and low T2* using logistic regression. Results. One hundred seventy-nine liver transplant candidates who received CMRI-T2* were included. Median age was 57 years, 73.2% were male, and 47.6% were white. 49.7% had hepatitis C and 2.8% had hemochromatosis. Median Model for End-Stage Liver Disease score was 25. 65.2% were Child-Pugh C. In multivariable logistic regression, T2* less than 20 ms (n = 35) was associated with Model for End-Stage Liver Disease score of 25 or greater (odds ratio [OR], 3.65; P = 0.007), Child-Pugh C (OR, 3.42; P = 0.03), and echocardiographic systolic ejection fraction less than 65% (OR, 2.24; P = 0.01). Posttransplant heart failure occurred exclusively in recipients with T2* less than 15 ms. Survival was worse in T2* 10 to 14.9 versus T2* of 20 ms or greater (hazard ratio, 3.85; P = 0.003), but not for 15 to 19.9 versus T2* of 20 ms or greater. Conclusions. Severity of liver disease and systolic dysfunction is associated with T2* less than 20 ms, though there was no difference in posttransplant outcomes between T2* 15 to 19.9 and T2* 20 ms or greater, suggesting that individuals with T2* of 15 ms or greater may be suitable transplant candidates. CMRI-T2* is an additional diagnostic tool in evaluating transplant candidates at high risk for posttransplant cardiac complications.