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

Secondary postoperative ischaemia due to venous occlusion is the most detri mental insult to free microvascular flaps. In an experimental rat free flap model the efficacy of long acting prostacyclin analogues iloprost (Ilomedi n(TM)) and cicaprost in venous occlusion induced postoperative ischaemia wa s studied. Free, microvascular groin naps were transplanted to the neck and the draini ng veins were temporarily occluded on the first postoperative day for a tot al of 20 min. In the untreated control group, haemorrhagic nap necrosis occ urred. Intravital microscopy after secondary ischaemia revealed nap areas w ithout reperfusion. The functional vessel density was significantly reduced . Reperfused capillaries were tortuous and significantly dilated. After rep erfusion the interstitial leakage of macromolecular dextran increased, indi cating loss of microvascular endothelial integrity. Intraarterial and intra venous applications of iloprost were able to diminish the ischaemic effects , giving a nap survival rate of 83%. Similar results were obtained by intra venous and enteral administration of cicaprost. Transcutaneous oxygen parti al pressure measurements confirmed the viability of the surviving naps. We conclude that both iloprost and cicaprost are effective in preventing venou s occlusion induced failure of free microvascular groin naps.