ANGIOGRAPHIC EVIDENCE OF PULMONARY VASOMOTION IN THE DOG

Abstract

The vasomotor activity of the pulmonary arteries was recorded by the technique of angiography in the dog. The contrast material was injected selectively via a catheter into the artery to be studied. Both the injection and X-ray exposure were electronically programmed from the R-wave of the ecg. Optimum dye injection and X-ray viewing times were established. This precise X-ray viewing permitted comparisons of arteries 0.2 to 0.3 mm. in diameter. Respiration affected the "run-off" of the contrast material but not the size of the visualized pulmonary arteries. Epinephrine, 5-hydroxytryptamine, metaraminol, and eucapnic hypoxia caused segmental narrowing and gnarling of smaller arteries while the larger, proximal vessels passively dilated. Qualitative differences in induced pulmonary vasoconstriction occurred.