Haemodynamic Shunts in Schistosomal Cor Pulmonale

Abstract

Schistosomiasis is an endemic disease in Egypt and is associated with a variety of visceral manifestations.The heavy invasion of the portal vein and tributaries by worms and ova leads to hepatosplenomegaly (Fig; A). In advanced cases the schistosome ova may embolize the lungs, lodging in the pulmonary arterioles and producing the picture of cor pulmonale (Zaky, 1952) with characteristic radiological findings (Special Plate, Figs. 1 and 2). This involvement of the portal and pulmonary circulations gives rise to important circulatory changes, and the haemodynamic shunts associated with these are the subject of this paper. Material ad MethodsThree patients with schistosomal cor pulmonale were studied by the following techniques.1. Right heart catheterization was performed in the usual manner, but multiple samples of blood were withdrawn from the pre-pulmonary wedge position, midway to the hilum, right or left pulmonary artery, and the main pulmonary artery.2. Dye-dhlution technique, with injection of Evans (azovan) blue dye into the aorta and sampling from the pulmonary artery, to demonstrate an aorto-pulmonary shunt via the bronchial arteries. One cardiac catheter was advanced to the pre-wedge position in the pulmonary artery, while another was introduced into the brachial artery and advanced to the upper part of the descending aorta (Special Plate, Fig. 3) This position was chosen in order to avoid the mouths of the coronary arteries and short-circuiting of the dye through the coronary sinus. It also ensures that the bronchial arteries receive a good quantity of dye, since they arise a short way below the catheter tip. The capacity of each catheter was 2.8 ml. One operator injected 10 ml.C of Evans blue into the arterial catheter as rapidly as possible, but giving a signal at the 3-ml. level, at which moment the other operator began to withdraw from the venous catheter for five seconds. This was the first sample, and it averaged 4 ml. The syringe was changed and the second sample of 2 ml. withdrawn from the blood in the catheter. The first sample represented blood withdrawn from the pulmonary artery during the first 1i seconds, and the second sample that withdrawn between 1l and 4 seconds. The samples of blood were examined in a Beckman spectrophotometer for the presence of dye.3. Aortic angiography with a balloon catheter to visualize the bronchial arteries and the pulmonary artery (Special Plate, Fig. 6). A No. 10 cardiac catheter had a rubber balloon fitted over the end hole, and two side holes were made proximal to this. The catheter was advanced via the brachial artery so that the tip lay in the descending aorta just below the lung hilum; 50 ml. of 76% " urografin " (sodium diatrizoate) was injected rapidly, causing the balloon to inflate and block aortic blood-flow, while the remainder of the contrast material escaped from the side holes. Radiographs were taken each second. Results Pulmonary CirculationThe presence of shunts between the bronchial arterial system and the pulmonary artery was suspected on t...