Further Observations on Experimentally Produced Arteriovenous Aneurysm. ∗

Abstract

Arteriovenous aneurysm studies which we have been pursuing have yielded findings, difficult of immediate interpretation. We found 1 the cardiac shadow uniformly enlarged on immediate postoperative fluoroscopic examination and confirmed this with roentgenograms. These dogs had been completely anesthetized with large doses of sodium barbital, and apparently as a result the postoperative pulse rates were slower. Later we found the heart size actually decreased immediately after opening of an A-V fistula. These latter dogs had been anesthetized with ether, and their heart rates were high. Ten dogs submitted to general anesthesia for abdominal operations for the production of intestinal adhesions, with gauze and iodine, were studied before and after the induction of anesthesia and operation. There was usually a decrease in the cardiac size, especially in the region of the right ventricle. The decrease was related to the height of the rise in the heart rate. In a few of these dogs in which the heart rate remained low there was little or no decrease in heart size.

In order to study the mechanism of the thrill and the effects of the lesions, 3 types of arteriovenous aneurysms have been produced. The original type I, commonly made and observed clinically, is the side to side anastomosis with a fistula between artery and vein. The second type II consisted in suturing of the proximal end of the artery into the side of the vein, thus adding the total arterial output of the specific artery to the venous return volume of the specific vein. The third type III was produced by suturing the proximal end of the artery to the proximal end of the vein, ligating the distal segment of the vein as well as that of the artery.