The Usefulness of Computed Tomography in Predicting Left Ventricular Outflow Tract Obstruction After Neonatal Arch Repair

Abstract

This study investigated the outcome after neonatal arch repair, and the usefulness of computed tomography (CT) in predicting the development of left ventricular outflow tract (LVOT) obstruction (LVOTO). A total of 150 neonates who underwent arch repair between 2008 and 2019 were included. The diameters of the aortic valve annulus (AVA) and LVOT in millimeters were measured with transthoracic echocardiography (TTE) or CT and indexed by subtracting body weight in kilograms. The outcomes of interest were the development of LVOTO (peak flow velocity > 3 m/s on TTE) and reintervention or reoperation for LVOTO. The median follow-up duration was 3.6 years. The rates of overall survival, freedom from reintervention for LVOTO, and freedom from the LVOTO development at 7 years were 93.7%, 88.2%, and 81.0%, respectively. In univariable Cox regression analysis, weight-indexed CT-measured LVOT diameter (concordance index [C-index] = 0.73, P = 0.002) and weight-indexed TTE-measured AVA diameter (C-index = 0.69, P = 0.001) were significant predictors of LVOTO. The maximal chi-square test identified the following cutoff values for predicting LVOTO: 1.4 for weight-indexed CT-measured LVOT diameter and 1.6 for weight-indexed TTE-measured AVA diameter. The high-risk group (both measures lower than the cutoff values) had a significantly lower rate of freedom from LVOTO development than the low-risk group (both measures higher than the cutoff values) (P < 0.001). The weight-indexed CT-measured LVOT diameter could be used to predict LVOTO development after neonatal arch repair, as an independent measure or complementary to traditional measures.