Early tricuspid regurgitation in hypoplastic left heart syndrome is not related to right ventricular function or mechanical dyssynchrony

ABSTRACT

BACKGROUND: Tricuspid regurgitation (TR) is associated with morbidity and mortality in hypoplastic left heart syndrome (HLHS). We have previously demonstrated that TR prior to stage 2 (S2) surgical palliation is related to tricuspid valve (TV) abnormalities, including dilated annulus and increased leaflet prolapse. Right ventricular (RV) dysfunction and mechanical dyssynchrony have been reported as causes for TR. Thus, we hypothesized that TR and abnormal TV parameters are associated with RV dysfunction. Objective: This study explored the relationship between TV and RV function using quantitative three dimensional echocardiography (3DE) measure of TV parameters and speckle tracking echocardiography (STE) of RV deformation, in HLHS with and without TR. METHODS: Forty-four HLHS patients with median age of 4.7 months (IQR 3.9-5.3) were prospectively recruited prior to S2 palliation. TV parameters assessed using 3DE, included vena contracta area (VCA), leaflet area, prolapse volume, tethering volume, annular bending angle and papillary muscle angle. RV systolic function was assessed by fractional area change and STE derived longitudinal and circumferential strain, strain rate and mechanical dyssynchrony index (MDI). The group was divided into those with (group A) and those without (group B) significant TR by qualitative assessment. RV functional parameters were compared between the two groups using Mann-Whitney signed rank test and Spearman correlation of TV leaflet and annulus area, prolapse and tethering volume, bending angle and VCA, to longitudinal and circumferential strain, strain rate and MDI were performed. RESULTS: Fourteen patients (32%) had moderate or greater TR (group A). RV function parameters were not different between group A and group B. There was no correlation between all 3DE TV parameters and STE RV deformation parameters. CONCLUSION: Contrary to our hypothesis, HLHS RV systolic dysfunction and mechanical dyssynchrony do not play a significant role in early TR. This finding suggests the mechanisms of early TR in HLHS are likely to be secondary to valve and leaflet differences. (AU)