DRUG MIXTURE WHICH IMPROVES SURVIVAL OF ISCHEMIC RABBIT EPIGASTRIC SKIN FLAPS

The chief aim of this study was to maximize flap survival by counterac ting the pathophysiological changes occurring during ischemia-reperfus ion. Rabbit epigastric skin flaps given 21 hours of ischemia were infu sed intra-arterially with selected drugs at the start of reperfusion. Compared with control infused ischemic flaps, which had a 33% survival rate on day 7 post-ischemia, significant improvement was found with v asodilators nitrendipine (61%) and prostacyclin (65%) and the thrombol ytic agent urokinase (65%); marginal improvement with the free radical scavenger desferrioxamine (53%); but no change with streptokinase (44 %), heparin (21%), and ATP-MgCl2 (35%). A drug mixture comprising all of these agents except streptokinase and urokinase produced 87% surviv al, suggesting an additive effect. Biochemical assays on skin homogena tes and blood implicated oxygen free radicals, neutrophil infiltration , and thromboxane in flap failure. These results imply that multiple f actors are responsible for ischemic flap failure and that a mixture of drugs needs to be infused to counteract all of the detrimental change s. (C) 1994 Wiley-Liss, Inc..