Effects of unfractionated heparin and low-molecular-weight heparin on colonic anastomoses in the presence of...

We aimed at investigating the effects of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) on the healing process of colonic anastomoses in the presence of peritonitis which is known to adversely affect the healing process.

Three groups of Wistar albino rats (n = 15 in each group) with experimental fecal peritonitis were studied. A 1-cm colonic segment was resected, and an end-to-end anastomosis was performed. The control group (group 1) was given no treatment; group 2 animals received 50 IU/kg s.c. UFH twice a day, and group 3 rats received LMWH at a dose of 1.5 mg/kg daily for 7 days postoperatively. Relaparotomy was done on day 7 in the surviving rats. The rats were sacrificed by resection of the colonic segment. The anastomosis bursting pressures were measured and the tissue samples from anastomosis lines were histopathologically examined.

The bursting pressures were significantly higher in UFH and LMWH groups as compared with the controls (p = 0.021 and p < 0.001, respectively), while there was no statistically significant difference between UFH and LMWH groups. Positive bacterial culture results were more common in controls (90%) than in the other two groups (p = 0.029 and p = 0.002, respectively). Also the polymorphonuclear leukocyte counts were higher (p = 0.005) and the fibrin formation more common (p = 0.007) in the controls. On the other hand, the number of fibroblasts was higher (p = 0.002) and collagen formation and revascularization more frequent (p = 0.001 and p = 0.001, respectively) in the UFH and LMWH groups.

UFH and LMWH may have positive effects on the healing process of colonic anastomoses in the presence of peritonitis.