Objective: Identifying preoperative pulmonary venous obstruction in total anomalous pulmonary venous connection (TAPVC) is important to guide treatment-planning and risk prognostication. No standardized echocardiographic definition of obstruction exists in the literature. Definitions based on absolute velocities are affected by technical limitations and variations in pulmonary venous return. We developed a metric to quantify pulmonary venous blood flow variation: pulmonary venous variability index (PVVI). We aimed to demonstrate its accuracy in defining obstruction.
Methods: All patients cared for with TAPVC at our institution were identiﬁed. Echocardiograms were reviewed, and maximum (Vmax), mean (Vmean), and minimum velocities (Vmin) along the pulmonary venous pathway were measured. PVVI was defined as (Vmax-Vmin)/Vmean. These metrics were compared to pressures measured by cardiac catheterization. Echocardiographic measures were then compared between the patients with and without clinical preoperative obstruction (defined as a need for preoperative intubation, catheter-based intervention, or surgery within one day of diagnosis), as well as pulmonary edema by chest X-ray and markers of lactic acidosis. 137 patients were included with 22 having catheterization pressure recordings.
Results: Maximum and mean velocity were not different between patients with catheter gradients ≥4 mmHg and <4 mmHg, while PVVI was significantly lower and minimum velocity higher in those with gradients ≥4 mmHg. The composite outcome of preoperative obstruction occurred in 51 patients (37%). Absolute velocities were not different between patients with and without clinical obstruction, while PVVI was significantly lower in patients with obstruction. All metrics except maximum velocity were associated with pulmonary edema; none were associated with blood gas metrics.
Conclusions: We developed a novel quantitative metric of pulmonary venous flow, which was superior to traditional echocardiographic metrics. Decreased PVVI was highly associated with elevated gradients measured by catheterization and clinical preoperative obstruction. These results should aid risk assessment and diagnosis preoperatively in patients with TAPVC.
Keywords: Congenital heart disease; Doppler echocardiography; Pediatric cardiology; Total anomalous pulmonary venous connection.
Copyright © 2021. Published by Elsevier Inc.