Secondary ischaemia in experimental free flaps--treatment by long acting prostacyclin analogues.

Secondary postoperative ischaemia due to venous occlusion is the most detrimental insult to free microvascular flaps. In an experimental rat free flap model the efficacy of long acting prostacyclin analogues iloprost (Ilomedin) and cicaprost in venous occlusion induced postoperative ischaemia was studied. Free, microvascular groin flaps were transplanted to the neck and the draining veins were temporarily occluded on the first postoperative day for a total of 20 min. In the untreated control group, haemorrhagic flap necrosis occurred. Intravital microscopy after secondary ischaemia revealed flap areas without reperfusion. The functional vessel density was significantly reduced. Reperfused capillaries were tortuous and significantly dilated. After reperfusion the interstitial leakage of macromolecular dextran increased, indicating loss of microvascular endothelial integrity. Intraarterial and intravenous applications of iloprost were able to diminish the ischaemic effects, giving a flap survival rate of 83%. Similar results were obtained by intravenous and enteral administration of cicaprost. Transcutaneous oxygen partial pressure measurements confirmed the viability of the surviving flaps. We conclude that both iloprost and cicaprost are effective in preventing venous occlusion induced failure of free microvascular groin flaps.

[Increasing the survival rate of endangered free microvascular tissue transplants using a prostacyclin derivative]. / Steigerung der Uberlebensrate gefährdeter freier mikrovaskulärer Gewebetransplantate mittels Prostacyclinderivat.

Free flap transplantations and replantations of extremities are threatened by venous occlusion due to haematomas, contusions, and secondary healing of the surrounding tissues. In an experimental investigation in 18 Sprague-Dawley-rats, the influence of the Prostacyclin analogue Iloprost on temporary ischemia by venous occlusion was tested. Free groin flaps were transplanted to the neck of these animals with microanastomoses of the nutrient superficial epigastric vessels to the carotid artery and the jugular vein. On the first postoperative day the vein was temporarily clamped. In the control group there was always a total loss of the flap by haemorrhagic necrosis. The intraarterial flap perfusion by Iloprost was able to diminish the effects of the secondary ischemia. In some cases shortly after the perfusion and always on the next day, positive oxygen pressures were measurable. 80% of the flaps survived.

Free flap survival improved by prostacyclin analogues.

Free flap transplantations and replantations of extremities are threatened by venous occlusion in the postoperative course. In rats, free autogenous groin flaps were transplanted to the neck using microsurgical techniques. On the first postoperative day, the draining vein of the flap was temporarily clamped. In the control group there was always a total loss of the flaps by haemorrhagic necrosis. The intraarterial flap perfusion by iloprost during the clamping was able to diminish the ischaemic effects; 80% of the flaps survived. The systemic application of iloprost by intravenous infusion reduced the ischaemic effects in a similar way. Serious complications such as intraabdominal bleeding or bleeding in the donor area were seen after intravenous administration. Cicaprost had a similar protective effect on flap ischaemia after intravenous infusion. Flap survival was comparable to iloprost. Severe complications seemed to be less. Prostacyclin analogues were able to diminish damage of secondary ischaemia caused by venous occlusion.