Dynamic Systolic Changes in Tricuspid Regurgitation Vena Contracta Size and Proximal Isovelocity Surface Area in Hypoplastic Left Heart Syndrome: A Three-Dimensional Color Doppler Echocardiography Study

ABSTRACT Purpose The purpose of our study was to investigate the dynamic changes in the vena contracta (VC) and proximal isovelocity surface area (PISA) through systole in patients with hypoplastic left heart syndrome (HLHS) and tricuspid regurgitation (TR), and to identify the stage of systole (early, mid, or late) where VC and PISA radius are optimal. Methods We prospectively studied 28 patients with HLHS using continuous 2D and 3D echocardiography (2DE, 3DE) (X7-2, iE33, Philips). 2D vena contracta width (VCW), 3D vena contracta area (VCA), and PISA radii (2D and 3D) were measured frame-by-frame throughout systole. The maximal 2D VCW, 3D VCA, and PISA radii in the first, middle, and last third of systole were compared, and correlations explored with 3D tricuspid annular areas, right atrial (RA) volumes and right ventricular (RV) volumes. Results In all, 35 datasets that met inclusion criteria were analyzed. On frame-by-frame analysis, maximal 2D VCW and 3D VCA were found in the 1st third of systole in 17% and 20% of studies, in the 2nd third in 34% and 31%, and final third in 49% and 49%. Similarly, the maximal 2D and 3D PISA radii were found in the 1st third of systole in 26% and 17% of studies, in the 2nd third in 28% and 34%, and in the final third in 46% and 49%. Conclusions In HLHS, detailed temporal analysis of TR associated VC and PISA by 2DE and 3DE reveals no reliable pattern predicting when in systole these parameters peak. Frame by frame measurement is necessary for identification of maximal VC and PISA radius on 2DE and 3DE color Doppler because the severity of TR could be underestimated due to temporal variability in VC and PISA.