Backgrounds: The impact of myocardial fibrosis on cardiac performance and clinical outcomes in patients with a functional single ventricle before stage-3 operation is unknown.
Objective: The purpose of this study is to investigate the prognostic value of myocardial fibrosis identified by cardiac magnetic resonance imaging (cMRI) in patients with univentricular heart diseases.
Methods: Consecutive 23 patients undergoing staged-3 surgical palliation with single ventricle physiology were prospectively scheduled to have cMRI study with late gadolinium enhancement (LGE) imaging and ventricle circumferential strain were examined.
Results: Of 23 patients (mean age 3.3±0.9 years), 6 (26%) had positive late gadolinium enhancement (LGE+) in the ventricular myocardium, median percent LGE was 3.0% (interquartile range 3.0% to 14.0%). Pre-Fontan examinations revealed that patients with LGE+ had increased end-diastolic volume index (142.8 ml/BSA vs. 113.8 ml/BSA; P=0.02), increased end-systolic volume index (101.0 ml/BSA vs. 72.2 ml/BSA); P=0.01) compared with those without LGE (LGE-). Patients with LGE have shown to have lower ventricular circumferential strain compared with the area without LGE (basal: −1.9±1.9% vs. −4.0±3.0%, P=0.046; mid: −3.9±2.1% vs −8.0±3.9%, P=0.007; apical: −3.9±2.4% vs. −8.2±2.8%, P=0.004). In contrast to LGE- group, patients in LGE+ group had decreased right ventricular ejection fraction (27.7±8.8% vs. 38.2±8.4%; P=0.02) as well as higher levels of BNP (99.2±75.7 pg/ml vs. 32.6±44.3 pg/ml, P=0.02). In addition, patients with LGE+ had higher score of Ross classification (2.5±0.55 vs. 2.0±0, P=0.02) and New York University Pediatric Heart Failure Index (11.0±3.5 vs. 7.8±1.1, P=0.01) than in LGE- group. Age at stage-2 palliation was significantly older in patients with LGE+ group than LGE- subjects (16.8±16 months vs. 8.8±3.4 months, P=0.03).
Conclusion: In this pre-stage-3 cMRI study, the age to stage-2 palliation may attribute to substantial myocardial fibrosis. The area of LGE was associated with impaired regional circumferential strain as well as disturbed ventricular performance. This novel strategy may provide a possible prognostic value of latent myocardial dysfunction after staged palliation.