Early partial systolic closure of the pulmonic valve relates to severity of pulmonary hypertension.

Ultrasound studies in pulmonary hypertension often show systolic partial closure of the pulmonic valve and early peaking of Doppler pulmonary flow velocity, but these findings are poorly understood. Our initial observations of earlier systolic partial closure with higher pulmonary pressures suggested that this phenomenon might relate to pressure. In 30 patients with documented pulmonary hypertension, the timing of systolic partial closure and the corresponding decrease in Doppler flow velocity related inversely to pulmonary artery pressure at catheterization. Peak flow preceded the systolic velocity decrease and also related inversely to pressure. Since changing flow velocity might reflect a changing driving force across the valve, we examined simultaneous high-fidelity catheter pressure tracings from the right ventricle and pulmonary artery from 24 patients with and without pulmonary hypertension. In 30 studies, a positive right ventricular to pulmonary artery pressure gradient was present early in systole, but the gradient decreased to a minimum value in mid-to-late systole. The timing of this minimum also related inversely to pressure. We conjectured that forces opposing ejection occur earlier in pulmonary hypertension, thereby decreasing the forward driving force and allowing earlier partial systolic closure.