Narrowing of Artery from Contraction of Experimentally Produced,Fibrous Capsule

Abstract

Previously the contractibility of capsules of young sterile fibrous tissue surrounding pulmonary lobes and intestinal segments, organs offering little resistance to the constriction, was studied; 1 ,²,³ whereas the present work concerns the contractibility of such tissue about arterial segments, where far greater resistance occurs.

Fourteen arteries, femoral and carotid, in 6 dogs, were handled. Initial treatment in each case: Under aseptic precautions, a short length of the vessel was exposed by incision and loosely wrapped once around with light, close-woven, collodion-impregnated, silk cloth or with thin rubber dam. This material was 3 cm. long and just wide enough loosely to encircle the vessel; after application, its opposing edges were fastened together with silk sutures. The wound was closed. Seven to 105 days after operation, the vessel was removed in toto, injected first with lipiodol at arterial pressure for roentgenographic determination of the size of the lumen, and injected afterward with formalin for fixation and section.

Two of the wounds became infected and the specimens were rejected. In the other cases, the findings were as follows: The envelop, bathed in a little sero-fibrinous exudate, lay loosely about the vessel. All adjacent tissues had developed a layer of fibrous tissue, 1 mm. or less in thickness, next to the foreign material, the layer on the inside of the envelop having developed from the adventitia of the artery and constituting a capsule around the vessel. This layer could be easily stripped from the muscularis. In the younger specimens, it was composed of closely packed, well preserved fibroblasts and, in the older ones of relatively acellular, largely hyalinized fibrous tissue. The muscularis and intima were without cellular change, and the lumen was quite empty. The size of the latter varied greatly, depending on the age of the specimen.