Pharmacological and pathophysiological effects of periadventitial stripping on immediate and subacute postoperative vasoconstriction in guinea pigs.

Mechanically induced vasospasm observed in the immediate post-operative period was investigated, and the effect of factors such as temporary clip applications and post-operative intervals were studied. Guinea pig "cervical internal carotid arteries" were used and temporary clips, chosen according to the diameter of the artery and systolic pressure, were applied for a standard period. The same procedure was applied on arteries in which periadventitial tissue had been removed using appropriate microsurgical techniques. On postoperative days 1, 5, and 10, arterial rings were removed while the animals were still alive and Endothelium Dependent Relaxations were measured using a bioassay system. Morphological investigations were also performed using light microscopy on the same arterial preparations. We observed no difference between perioperative and first day postoperative results. The relaxations were minimum. The most striking pathological changes were observed on postoperative day 5, and the relaxation responses began to rise on day 10 together with morphological improvement. It was also found that periadventitial tissue stripping could be used to prevent subacute post-operative vasoconstriction, since its effect was marked on postoperative day 5 and began to resolve on day 10.