Echocardiographic Prediction of Hemodynamics During Acute Vasoreactivity Testing in Pediatric Pulmonary Arterial...

In pediatric pulmonary arterial hypertension (PAH), echocardiography is frequently used to assess response to acute vasodilator therapy. We sought to evaluate whether echocardiography is sensitive enough to detect significant changes in hemodynamics using two commonly used thresholds (Barst and Sitbon criteria) as benchmarks to establish a positive response.

Simultaneous echocardiography and invasive hemodynamics were obtained in 71 children with PAH at their baseline and maximal vasodilatory conditions. The change in echocardiographic parameters was used to predict AVT responder status as determined by Barst and Sitbon criteria.

There were strong positive correlations between invasive hemodynamics and echocardiographic markers of pulmonary hypertension. Between the baseline and AVT conditions, there were significant reductions in the tricuspid valve regurgitation velocity (TR Vmax), right ventricular systolic-to-diastolic ratio (S/D ratio), and systolic and maximal eccentricity index (EIs and EIm). Barst criteria responders had more pronounced reductions in S/D ratio and EIm. A 22.5% decrease in TR Vmax, 48.2% in S/D ratio, and 29.0% in EIm were associated with positive Barst responder status. The degree of change in echocardiographic variables was not strongly associated with clinical outcomes.

Using simultaneously obtained invasive hemodynamics and echocardiography, this is the first study to demonstrate that there are appreciable changes in echocardiographic markers of pulmonary hypertension during acute vasoreactivity testing (AVT) in children. The degree of change in three of these parameters (TR Vmax, S/D ratio, and EIm) was the most useful in identifying those with a more pronounced response to pulmonary vasodilatory therapy. Future studies are needed to validate these findings and establish a prognostic significance.