Experimental Studies in Vascular Repair

Though the presence of vasa vasorum in the walls of arteries and veins has been recognized for almost 200 years, relatively little is known about their precise function and their r6le in vascular repair. There has been much controversy in the literature as to whether there is a causal relationship between disease of the vasa and of the parent vessels, or whether alterations in the vasa are secondary to pathological changes in the arteries. Considerable light has been thrown upon the part the vasa may play in experimental angiitis and in clinical arteriosclerosis by the extensive observations of Winternitz and his associates.' 8' 9'10 1" It is entirely likely that the vasa may have great importance in the repair of sutured vessels and in the survival of free vein transplants. It was with these specific problems in mind that the present studies were undertaken. This report, however, is limited to our preliminary experiences with a particular method of studying the vasa and to a description of certain morphologic characteristics of the vasa of normal arteries and veins. In the past, two methods have been utilized to demonstrate the vasa. The first depends upon their detection in certain preparations fixed and stained in the ordinary manner; this technique has very limited possibilities. The second, which is responsible for most of the contributions thus far made, involves the filling of the vasa by the injection, under high pressure, of the artery or vein with engrossing ink or some other agent such as Berlin blue. Following injection and fixation, the vessel is dehydrated and cleared. This is the method which was used with great success by Winternitz and his co-workers. Injection methods have been utilized for many years; the report of Ramsey et al.' contains a review of the early efforts with this technique directed towards an inquiry into the pathology of vascular disease.