PREOPERATIVE EVALUATION OF THE PULMONARY VASCULAR BED IN PATIENTS WITH PULMONARY HYPERTENSION ASSOCIATED WITH LEFT TO RIGHT SHUNTS

Abstract

Eighteen patients with pulmonary hypertension associated with left to right cardiac shunts have been studied using acetylcholine injected into the pulmonary artery to determine the distensibility of the vascular bed. The response is considered as an index of severity of vascular disease and of operative risk. Six cases failed to respond to the drug. One of these had received atropine, and the data may not be reliable. Five were 6 years of age or older and had relatively less left to right shunting than the others. Surgery was performed in two of this group of six, and it proved fatal. The small pulmonary arteries in both patients had marked intimal disease. All of the 12 cases that responded to acetylcholine had shunting of at least 140% of the systemic flow, and in five patients tested the shunt increased following injection of the drug. The five cases operated upon from this group had hypertrophy of the media of the small pulmonary arteries and in two cases minimal proliferation of the intima was present. The pulmonary artery pressures were similar in both groups. These observations suggest that the severity of pulmonary vascular disease may be predicted by the method described.