Experimental Study On Dynamic Changes And Significance Of TF And TFPI In Early Venous Crisis Of Free Perforator Flap

Objective To investigate the dynamic changes of peripheral blood tissue factor(TF), tissue factor pathway inhibitor(TFPI) and probe their significance in order to find an effective method to warn venous crisis early after free perforator flap transplantation.Methods Thirty healthy New Zealand white rabbits were chosen and randomly divided into experimental group (n=15) and control group (n=15), all of them were transplanted with free superficial epigastric artery perforator flap. The anastomosis veins were ligated in the experimental group in order to interrupt the blood outflow of perforator flap to form venous crisis. Intervening measures were not implemented in the control group. All of Rabbits were drawn peripheral arterial blood in different points:preoperative, flap reflow immediately, ligating vein immediately, ligating vein with15minutes,30minutes.1hour,2hours,4hours,6hours,8hours respectively. The concentration of TF and TFPI of peripheral blood were detected with Enzyme linked immunosorbent assay(ELISA). An amount of flap tissue were harvested for pathological observation.Results Compared with the control group, the concentration of TF in peripheral blood is higher in the experimental group since30minutes after the vein was lighted. the difference has statistical significance between the two groups(P<0.05). However, The differences between the two groups about the concentration of TFPI in peripheral blood have no statistical significance(P>0.05). The concentration of TF in experimental group gradually increased after operation, and reached the peak when the flap was reflowed immediately, and then gradually recovered to preoperative level. With occurring venous crisis of flap, the concentration of TF increased gradually and began to appear obviously statistical difference at thirty minutes. The concentration of TFPI in the two groups have temporary decreased from preoperative to intraoperative, And then there were no obvious changes after operation. The statistical results showed that there is no statistical difference between the two groups at different time points. The pathological examination showed that red blood cells gradually gathered together in microcirculation after flap venous crisis happened; The microcirculation has not been blocked completely4hours after flap venous crisis occurred; Flap tissue has occurred irreversible necrosis and the microcirculation of flap has been embolizated completely8hours after venous crisis occurred.Conclusion Obvious increase of TF concentration can be detected thirty minutes after venous crisis occurred, TF maybe become an alarm sign for warning early venous crisis of perforator flap. The concentration of TFPI have no obvious change after venous crisis of perforator flap occurred, TFPI has no significance for warning venous crisis of free perforator flap early.