PHARMACOLOGICAL AND PATHOPHYSIOLOGICAL EFFECTS OF PERIADVENTITIAL STRIPPING ON IMMEDIATE AND SUBACUTE POSTOPERATIVE VASOCONSTRICTION IN GUINEA-PIGS

Mechanically induced vasospasm observed in the immediate post-operativ e period was investigated, and the effect of factors such as temporary clip applications and post-operative intervals were studied. Guinea p ig ''cervical internal carotid arteries'' were used and temporary clip s, chosen according to the diameter of the artery and systolic pressur e, were applied for a standard period. The same procedure was applied on arteries in which periadventitial tissue had been removed using app ropriate microsurgical techniques. On postoperative days 1, 5, and 10, arterial rings were removed while the animals were still alive and En dothelium Dependent Relaxations were measured using a bioassay system. Morphological investigations were also performed using light microsco py on the same arterial preparations. We observed no difference betwee n perioperative and first day postoperative results. The relaxations w ere minimum. The most striking pathological changes were observed on p ostoperative day 5, and the relaxation responses began to rise on day 10 together with morphological improvement. It was also found that per iadventitial tissue stripping could be used to prevent subacute post-o perative vasoconstriction, since its effect was marked on postoperativ e day 5 and beginned to resolve on day 10.