The behavior of residual pulmonary artery gradient after arterial switch operation: A longitudinal data analysis

The arterial switch operation (ASO) is the standard treatment for the transposition of the great arteries. The timely variation in the residual pressure gradient across the pulmonary arteries is ill-defined. This study is aimed to study the progressive changes in the pressure gradient across the pulmonary valve and pulmonary arteries after ASO.

All eligible patients for this study who underwent ASO between 2000 and 2019 were reviewed. Transthoracic echocardiography was used to estimate the peak pressure gradient across the pulmonary artery and its branches. The primary outcome was the total peak pressure gradient (TPG) which is the sum of peak pressure gradients across the main pulmonary artery and pulmonary artery branches. Furthermore, longitudinal data analyses with mixed-effect modeling were used to determine the independent predictors for the changes in the pressure gradient.

Three hundred and nine patients were included in the study. Over a 17-year follow-up, the freedom from pulmonary stenosis reintervention was 95% (16 out of the 309 patients underwent reintervention = 5%). The longitudinal data analyses of serial 1844 echocardiographic studies for the included patients revealed that the TPG recorded in the first postoperative echocardiogram across pulmonary valve, right and left pulmonary artery branches was the most significant predictor for reintervention.

The total peak gradient measured in the first postoperative echocardiogram is the most important predictor for reintervention. We propose that a total peak gradient in the first postoperative echocardiography of 55 mm Hg or more is a predictor for reintervention.