Myocardial Scar Burden Correlates with NT-proBNP Levels and Changes in Left Ventricular Filling Pressures in Heart Transplant Recipients

Abstract

Purpose Although myocardial scar burden represents an established prognostic marker in heart failure, its predictive value after heart transplantation (HTX) remains poorly defined. We sought to investigate clinical correlates and prognostic impact of myocardial scar burden in patients after HTX. Methods In a prospective single-center study we enrolled 112 consecutive HTX recipients transplanted between 2010 and 2018. At 1-year after HTX all patients underwent cardiac echo and cardiac magnetic resonance imaging (cMRI). Cardiac echo was repeated again at 2 years after HTX. Patients with a history of primary graft dysfunction, CAV or history of rejection >1R were excluded. Allograft myocardial fibrosis was quantified with late gadolinium enhancement (LGE). Results Extent of myocardial fibrosis was above mean value (2.5%) in 54 patients (48%; Group A) and below mean in 58 patients (52%; Group B). The two groups did not differ in age (56±8 years in Group A vs. 54±11 years in Group B,P=0.10), gender (male: 87% vs. 73%,P=0.25), creatinine (92±19 μmol/L vs. 92±22 μmol/L,P=0.96), troponin (0.01±0.02 μg/L vs. 0.01±0.04 μg/L,P=0.64), tacrolimus trough levels (7.1±1.8 μg/L vs. 7.3±1.6 μg/L,P=0.54), the presence of hypertension (48% vs. 63%,P=0.11) or diabetes (33% vs. 24%,P=0.11). The two groups also had similar rates of pre-transplant LVAD support (11% in Group A vs. 17% in Group B,P=0.33) and comparable allograft ischemic time (185±76 min vs. 199±69 min,P=0.30). On echocardiography we found no differences in LVEF (66.4±8.4% in Group A vs. 66.1±6.8% in Group B,P=0.79), TAPSE (1.57±0.34 cm vs. 1.58±0.38 cm,P=0.80) or E/e’ (10.6±3.9 vs. 11.2±4.1,P=0.42). However, we found significantly higher NT-proBNP levels in Group A than in Group B (median: 693 pg/mL (IQR 210-716) vs. 366 pg/mL (IQR 160-514),P=0.04). At 1 year after cMRI E/e’ increased in Group A, but not in Group B (+2.8±4.9 vs. 0.1±4.9,P=0.004); the same was observed when analyzing changes in NT-proBNP (+93.4±455.9 pg/mL in Group A vs. -12.1±158.2 pg/mL in Group B,P=0.03). Conclusion In HTX recipients myocardial scar burden appears to correlate with serum levels of NT-proBNP. High myocardial scar burden at 1 year post HTX may be associated with subsequent increases in left ventricular filling pressures and could thus serve as a predictor of adverse remodeling of the transplanted allograft.