University of Alberta
Summary of research:
Background: Neonates with severe Ebstein’s anomaly and tricuspid valve dysplasia (EA/TVD) are often hemodynamically unstable with low systemic perfusion and hypoxia; whereas, this is uncommon in another critical right heart lesion, pulmonary atresia with intact ventricular septum (PAIVS). We have recently demonstrated left ventricular (LV) dysfunction and dyssynchrony to be common in fetal EA/TVD but not PAIVS. In the current study we sought to explore LV function and mechanics in neonatal EA/TVD with comparison to PAIVS in the early neonatal period. Methods: We identified cases of neonatal EA/TVD (n=30) and PAIVS (n=17) encountered from 2004-2018. We assessed LV function using 2D, Doppler-derived, longitudinal and circumferential deformation (6-segmental Vector Velocity Imaging) and dyssynchrony indices (standard deviation of time-to-peak, T2PSD) and a novel global dyssynchrony index (DI) in the first 48 hours after birth. Results are described as mean ± standard deviation, or median (95% confidence intervals). Comparisons between diagnostic groups were performed using t-test and Wilcoxon test. Results: Gestation at birth was earlier in EA/TVD than PAIVS (36.4 ± 2.2 weeks vs 38.1±2.4 weeks p=0.03). Five cases of EA/TVD required extra-corporeal membrane oxygenation. 1 EA/TVD and 1 PAIVS died in the first 30 days. 16 cases in EA/TVD had antegrade flow from the right ventricle.The LV fractional area change and global circumferential strain were reduced in EA/TVD [EA/TVD 41.9% (37.9-48.1) vs PAIVS 51.9% (48.1-54.5) p=0.002; EA/TVD -15.9% (-12.1 - -17.7 vs PAIVS -24.1% (-19.9 - -24.5) p<0.001), and the septum was flattened (eccentricity index EA/TVD 1.33 (1.26-1.46) vs PAIVS 1.04 (1.01-1.17), p<0.001). There was increased dyssynchrony in EA/TVD (DI of Radial Strain 0.14 (0.12-0.3) vs 0.05 (0.02-0.17) p=0.006; DI of Circumferential Strain 0.17 (0.16-0.35) vs 0.08 (0.05-0.1) p=0.003). Left ventricular ejection fraction, global longitudinal strain, cardiac output and LV Tei index were not different between EA/TVD and PAIVS. Conclusion: LV radial and circumferential deformation was impaired in cases of EA/TVD, with increased dyssynchrony. Further work will examine the impact of LV mechanics on outcome and requirements for medical support in early life.