Defining the best echocardiographic parameter to predict acute rejection after heart transplantation

Acute allograft rejection (AR) is the major cause of morbidity and mortality the first year after heart transplantation (HT), beeing endomyocardial biopsy (EB) the gold standard procedure to diagnose it. Our group has previously developed a protocol to evaluate echocardiographic parameters and 2D strain in the first year after HT. Our aim was to evaluate which is the best non-invasive measurement to predict AR. Methods: We prospectively included 34 HT recipients between 2009-12. A median of 7 Echocardiograms and EB were performed for each patient during the first year after HT (the same day). We measured left ventricular (LV) longitudinal strain (Long.S) in 4 and 2-chamber views using speckle tracking. Right ventricular (RV) strain was obtained from a 4-chamber view. AR by EB was graded according to ISHLT recommendations. Results: We analyzed a total of 224 EB and echo exams. AR was detected in 59 EBs (48 1R, 8 2R and 3 3R). 3 different LV parameters and 2 RV measures were significantly associated with AR on univariate analysis, comparing AR vs no-rejection: Interventricular septal thickness (IVST) 12.4±2.1 vs 11.3±1.8, p<0.005, Isovolumic Relaxation Time (IVRT) 80.6±19.4 vs 93.3±17.9, p<0.005; LV long.S -14.6±3.5 vs -17.8±3.5, p<0.005; RV Thickness 5.7±1.3 vs 5.2±1.1, p=0.02; RV Free Wall S -16.6±3.1 vs -23.4±5.3, p<0.005. IVST, LV Long.S and RV free-wall S were the three independent predictors for AR on multivariate analysis (Table 1). The best area under the ROC curve was provided by RV free-wall S (AUC 0.87, CI 0.82-0.92, p<0.001) View this table: Multivariate analysis to predict AR Conclusion: Myocardial deformation parameters, specially free-wall right ventricular longitudinal strain, are useful tools to detect AR in the first year after HT, providing further information over conventional echo parameters. This findings could be usefull to reduce the burden of repeated EB in the early HT period.