Abstract Body (Do not enter title and authors here): Background: Multiparametric cardiac magnetic resonance (CMR) serves as the gold standard for evaluating cardiac structure and function in vivo, and allows assessing myocardial tissue characterization non-invasively, providing a potential alternative for identifying significant acute cardiac allograft rejection (SR).
Aims: This study aimed to evaluate the association between CMR multiparameters and SR, and assess the incremental value of CMR multiparameters over conventional serum examinations for identifying SR using the likelihood ratio analysis.
Methods and results: Heart transplantation (HTx) recipients with endomyocardial biopsy and healthy controls were prospectively recruited for CMR assessment. CMR feature tracking (CMR-FT) was performed to evaluate the left ventricular (LV) global strain in all three directions. The last serum examinations including N-terminal pro brain natriuretic peptide (NT-proBNP) before anti-rejection therapy were recorded. Participants were divided into 3 groups based on biopsy grade: control, SR (acute cellular rejection [ACR] grade≥2R and/or antibody-mediated rejection [AMR] grade≥pAMR1), and NSR (ACR grade<2R and AMR grade=pAMR0). Finally, thirty controls (43.3±13.6 years, 26 male) and 51 HTx recipients comprising 23 SRs (48.6±12.6 years, 24 male) and 28 NSRs (42.7±14.9 years, 16 male) were enrolled for analysis. Compared with NSRs, SRs showed elevated NT-proBNP (7797.0±7527.6pg/ml vs 3334.6±5935.3pg/ml, p<.001), worse LV global longitudinal strain (GLS) (-9.7±3.1% vs -13.1±2.9%, p<.001), and increased native T1 (1384±80.1ms vs 1321±69.9ms, p<.001) and T2 values (50.9±2.7ms vs 45.7±4.3ms, p<.001). In multivariable analysis, LVGLS (OR=0.76, 95%CI, 0.59 to 0.98, p=.03) and T2 value (OR=1.35, 95%CI, 1.10 to 1.65, p=.01) were independently associated with SR after NT-proBNP adjustment. Furthermore, the likelihood ratio test showed LVGLS (p=.002) and T2 value (p<.001) had incremental value over NT-proBNP for identifying SR.
Conclusion: LV GLS and T2 value were independently associated with SR, providing incremental value for non-invasive identification of significant rejection in HTx recipients.