Effects of hypoxia and hyperoxia on progression of intimal healing

To assess the effect of changes in inspired oxygen concentration on intimal healing, the aorta was stripped by a single passage of an inflated embolectomy catheter in 34 rabbits. Each then was maintained in a controlled-atmosphere cage with a normobaric oxygen concentration of 14%, 21%, or 40% for up to ten days. Although after six months all animals showed nearly normal aortic healing, the progression of healing was considerably different. Hypoxia appears to result in prolonged platelet adherence, exaggerated medial proliferation, and aberrant migration. Hyperoxia appears to allow a more orderly intimalization. An aberrant healing process secondary to tissue hypoxia when combined with exacerbating factors may be important in producing the unfavorable result in vascular surgery.