Seguimiento de Características por Resonancia Magnética Cardíaca para la Vigilancia de Rechazo después de Trasplante...

Endomyocardial biopsy (EMB) is the standard invasive method for monitoring acute cardiac allograft rejection (ACAR); however, non-invasive alternatives are increasingly proving to be dependable.

We aimed to identify and validate dependable CMR strain indices for ACAR detection.

We analysed 160 CMR scans, including long- (LAX), short-axis (SAX) cines, and T1/T2 maps from 54 transplant recipients. Uniparametric and multiparametric models integrating left ventricular strain metrics and tissue characteristics were developed to classify histological rejection grades (0, 1R, ≥2R) and evaluate therapeutic response.

Regression analysis using generalised linear mixed-models identified significant differences between rejection groups, with global radial strain (GRS) (z-value=3.1, p=0.002) and global circumferential strain (GCS) (z-value=2.5 p<0.008) outperforming global longitudinal strain (GLS) in discriminating ≥2R from 1R rejection. Diagnostic performance for detecting ≥2R rejection was excellent, particularly for GCS (AUC=0.852, NPV=98.3%) and GRS (AUC=0.826, NPV=95.8%), with enhanced accuracy in the anterolateral mid-basal segments (AUC>0.886, NPV>97.9%). Strain metrics effectively monitored recovery post-therapy for ≥2R rejection, showing significant improvements (GRS Δ24.5 ± 7.1%, GCS Δ15.9 ± 4.6%, GLS Δ27.4 ± 11.8%, all p<0.02). Furthermore, as strained-based detection of ≥2R rejection correlated with increases in oedema detected using T1/T2 mapping (all p<0.001), integrating strain with T1/T2 mapping significantly enhanced diagnostic accuracy, with T2+GRS (AUC=0.931, NPV=98.2) and T1+T2+GCS (AUC = 0.943, NPV=97.5) as the most effective models.

Segmental CMR strain analysis demonstrates excellent diagnostic accuracy and negative predictive value for detecting high-grade ACAR and monitoring post-therapy recovery. This non-invasive approach, particularly when integrated with multiparametric models combining global strain and tissue mapping, has the potential to reduce reliance on invasive EMBs for ACAR surveillance in cardiac transplant recipients.