PULMONARY HEMODYNAMICS AND BLOOD-FLOW CHARACTERISTICS IN CHRONIC PULMONARY-HYPERTENSION

Background. Lung transplantation is now an acceptable form of therapy for pulmonary hypertension, but controversy remains regarding the most appropriate surgical procedure. In this study, the changes in pulmona ry vascular mechanics occurring in the setting of pulmonary hypertensi on were investigated using an adult canine model of monocrotaline pyrr ole-induced pulmonary hypertension. Methods. Animals underwent pulmona ry artery catheterization to measure right heart pressures before and 8 weeks after injection of either 3 mg/kg of monocrotaline pyrrole (n = 8) or placebo (n = 8). Eight weeks after injection, hearts underwent instrumentation with an ultrasonic flow probe and micromanometers. Ha rmonic derivation of functional data was achieved with Fourier analysi s. Results. Significant increases in mean pulmonary artery pressure an d pulmonary vascular resistance were observed after monocrotaline pyrr ole injection. There was no significant difference in pulmonary blood flow. However, significant increases in input resistance and right ven tricular hydraulic power with significant decreases in transpulmonary efficiency were observed. Conclusions. Pulmonary hypertension causes s ignificant alterations in pulmonary hemodynamics. Pulmonary blood flow is maintained by a significant increase in total power but with a sig nificant decrease in transpulmonary efficiency. This adult canine mode l of pulmonary hypertension provides a useful means by which to evalua te surgical options of lung transplantation for improving pulmonary he modynamics in the setting of chronic pulmonary hypertension. (C) 1997 by The Society of Thoracic Surgeons.