Evaluation of a Continuous Systemic Infusion of Iloprost, A Stable PGI-2 Analog, on the Survival of Experimental Skin Flaps

ABSTRACT

Numerous investigators have attempted to enhance the survival of ischemic experimental skin flaps using various pharmacologic manipulations. Recently, the authors' laboratory demonstrated the beneficial effect of iloprost, a stable PGI₂ analogue, as a post-ischemic perfusion washout, in improving the survival of ischemic skin flaps.

The rat unilateral abdominal skin flap, based on the superficial epigastric vessels, was utilized in this study involving 30 animals. The animals were divided into three different treatment groups, with ischemic periods of 16 and 18 hr. Perfusion washouts were performed at the completion of the various ischemic periods. Alzet osmotic pumps were used to deliver a continuous systemic infusion of iloprost for 7 days postoperatively. The groups consisted of the following: Group 1 (single ILO)-perfusion washout with iloprost only; Group 2 (continuous LD ILO)-low-dose systemic iloprost infusion (0.066 mcg/kg/min) and perfusion washout with iloprost; and Group 3 (continuous HD ILO)-high-dose systemic iloprost infusion (0.1 mcg/kg/min) and perfusion washout with iloprost.

The percentage of flap survival was assessed on postoperative day 7. Skin flaps of the animals receiving the continuous systemic infusion of iloprost were noted to have varying percentages of survival, while skin flaps undergoing perfusion washout only were found to have either complete survival or full necrosis. At the 5 percent significance level, there was no significant improvement in skin-flap survival using a continuous systemic infusion of iloprost, compared to iloprost perfusion washout alone. In addition, the hypotensive side effects of systemic iloprost infusion limit its use in the rat skin-flap model.