Ventricular and pulmonary artery volumes in patients with absent pulmonary valve. Factors affecting the natural course.

Right and left ventricular (RV and LV) volumes were determined in 19 patients with absent pulmonary valve syndrome using Simpson's rule and area-length methods. The volume of the proximal right pulmonary artery (RPAV) was calculated at maximal and minimal size using the area-length method. Patient groups included four newborns who responded to medical management (group 1A), seven critically ill newborns who died (group 1B), four infants ages 1-10 months (group 2) and four children ages 2-8 years (group 3). The RV end-diastolic volume in groups 1B and 2 was significantly greater than that in groups 1A and 3. The RV ejection fraction in groups 1B and 2 was significantly less than that in normal patients and groups 1A and 3. Maximal RPAV correlated well with RV stroke volume and end-diastolic volume. The maximal RPAV in group 1B was significantly greater than that in groups 1A and 3. Pulmonary arterial compliance was greater than normal in all groups, and the compliance in group 1B was more than two times that in the other groups. We conclude that the increased right pulmonary artery compliance and pulmonary regurgitation in patients with absent pulmonary valve contribute to bronchial obstruction and right-heart failure and are the causes of the high morbidity and mortality in these patients. The management should be directed to the alleviation of bronchial obstruction and right-heart failure.