SEDIMENTATION OF FORMED ELEMENTS IN DISTALLY ISCHEMIC FLAPS

Our aim was to find out whether thrombosis has a key role in distally ischaemic flaps and whether heparin improves flap survival in distally ischaemic myocutaneous and pure skin flaps in pigs. In experiment 1 w e measured the concentration of coagulation factors in the venous effl uent from both viable flaps and distally ischaemic flaps. In experimen t 2 radioactively labelled blood components (red cells, platelets and fibrinogen) were injected intravenously and the distribution of each t racer was measured. In experiment 3 either heparin or saline was given as a local, continuous direct intra-arterial infusion. Fluorescein wa s used in all experiments to estimate the eventual flap survival. Our results indicate that thrombosis is not an important factor in distal ischaemia, and that heparin did not improve survival. Instead, there s eems to be selective pooling of formed elements in the ischaemic porti on of the flap.