0443: 3D transthoracic echocardiography assessment of the pulmonary valve in patients with TOF

Abstract

Accurate evaluation of pulmonary valve (PV) morphology and pulmonary annulus (PA) diameter is crucial before surgical correction of tetralogy of Fallot (TOF). Our aim was to assess PV morphology using three-dimensional transthoracic echocardiography (3D-TTE) in infants with TOF before surgical correction. And to compare PA diameter obtained by different imaging modalities. 30 patients with TOF were prospectively included. All patients underwent 2D and 3D-TTE, 23 patients underwent CT-Scan and 7 cardiac catheterization. PA diameter was measured using 2D-TTE in parasternal short axis view as recommended. 3D dataset was acquired using zoom mode at PV. Both vertical (Dv) and horizontal (Dh) diameters of PA were measured. Mean 3D diameter (3DD) was calculated as (Dv+Dh/2). Eccentricity index (EI) of PA was calculated (Dv—Dh/Dv). These measurements were compared to CT-Scan and angiography when available and to perioperative measurements. Mean age 7.4 months (3-24 months), mean weight 6.6kg (4.5-13.5kg). PV was described as bicuspid in 15/30 patients by 3D-TTE from en face view, with 75% agreement between 3D-TTE and perioperative finding (20/30 patients). PA geometry was slightly asymmetric by 3D-TTE. Dv was significantly larger than Dh (8.4mm vs 7.4mm, p=0.001), and mean EI of PA was (10%). PA was more asymmetric in bicuspid valves rather than in tricuspid valves (EI 14% vs 7%, p=0.002). PA diameter didn’t differ significantly between 2D-TTE, Dh, CT scan and angiography, and were significantly lower than mean 3DD and Dv. There was a very strong correlation between 3DD and perioperative measurement. PA was conserved in 53.3% without significant residual stenosis immediately and after a 20 month of follow-up (except 1 patient requiring balloon dilatation). 3D-TTE in patients with TOF is an accurate method to describe PV, and to measure PA size. Thus could help the surgical repair and the preservation of PV function.