THE EFFECT OF ISCHEMIC CONDITIONING ON GASTRIC WOUND-HEALING IN THE RAT - IMPLICATIONS FOR ESOPHAGEAL REPLACEMENT WITH STOMACH

Background. Esophagectomy, with gastric pull up replacement, is not un commonly complicated by leakage from the esophagogastrostomy anastomos is. Occult ischemia of the mobilized gastric fundus is a major etiolog ical factor for anastomotic leakage. Gastric tissue perfusion can be i mproved by ischemic conditioning (''delay'' phenomenon). Objective. To test the hypothesis that ischemic conditioning will improve gastric w ound healing, and reduce the incidence of anastomotic dehiscence, in a rodent model of partial gastric devascularization. Experimental desig n. Laboratory study of gastric wound healing in rats. Animals. Forty-f ive Sprague-Dawley rats (3 groups of 15 rats). Interventions. All anim als underwent laparotomy on day 0. Group 1 (control) and group 3 (acut e ischemia) rats had sham laparotomies done. Group 2 (ischemic conditi oning) rats underwent laparotomy and left gastric artery ligation. On postoperative day 14, all animals underwent repeat laparotomy; gastrot omy wounds were created and sutured. Group 1 (control) and group 2 (is chemic conditioning) rats had gastrotomy alone, while group 3 (acute i schemia) rats also underwent left gastric artery ligation. All rats we re sacrificed 5 days after gastrotomy and wound healing was assessed. Measures. Gastrotomy wounds were assessed for dehiscence, bursting str ength, and hydroxyproline concentration. Results. Anastomotic dehiscen ce did not occur in group 1 (control) or group 2 (ischemic conditionin g) rats. Four of 15 rats (27%) in group 3 (acute ischemia) suffered an astomotic dehiscence (p=0.028). Wound bursting pressure in the three g roups was not significantly different (group 1 - 96.3+/-8.3 mmHg, grou p 2 - 91.1+/-4.8 mmHg, group 3 - 70.9+/-12.7 mmHg, p=0.13). Wound hydr oxyproline concentration in the control group was significantly higher than in the other 2 groups (group 1 - 0.124+/-0.005 mu mol/mg, group 2 - 0.113+/-0.007 mu mol/mg, group 3 - 0.102+/-0.006 mu mol/mg, p=0.04 ), but there was no difference between the acute ischemia and the isch emic conditioning groups (p=0.24). Conclusions. In this rodent model o f partial gastric devascularization, ischemic conditioning reduced the incidence of anastomotic dehiscence. Wound bursting strength and hydr oxyproline concentration were not affected by ischemic conditioning. T herefore, the harmful effect of ischemia, and the beneficial effect of ischemic conditioning, are probably not primarily related to synthesi s of wound collagen. Ischemic conditioning of the stomach is a concept that may prove clinically useful in reducing the incidence of leakage from esophagogastrostomy anastomoses.