The impact of low molecular weight heparin on survival of reverse-flow island flaps: an experimental study in rabbits

Abstract

Objective To evaluate the effect of low molecular weight heparin on the survival of reverse-flow island flaps. Methods A saphenous vessel reverse-flow island flap model was established on both hind limbs in 10 New Zealand white rabbits that were randomly divided into 2 groups. Each group had 10 flaps. The flap area was 3 cm×3 cm. The vascular pedicle length was 4 cm, and the width of the fascia reserved around the saphenous vessels was about 1 cm. In group A (control) the rabbits received no treatment after flap elevation and suture. In group B (experiment) 200 IU/kg low molecular weight heparin was administered via subcutaneous injection once a day for 5 days. Flap perfusion and drainage, color and swelling were observed daily for one week when flap survival was evaluated. Results Blood circulation of the flaps was good in the early postoperative stage. After 1 to 2 days, blood oozing from flap edges stopped in group A. The flaps began to appear obviously edematous, and the color of the flaps turned dark purple.In group B, oozing from the edge of the flaps lasted significantly longer. There was no obvious venous congestion or swelling. Seven days after flap elevation, the mean percentage of survival area of the flaps was (89.5±15.2)% in group A and (97.5±5.4)% in group B, respectively. The difference was significant (P<0.01). Conclusion The application of low molecular weight heparin via subcutaneous injection can improve microcirculation within the flap and increase the quality of flap survival by releasing the load of venous congestion through prolonged oozing from flap edges. Key words: Surgical flaps; Animal experimentation; Venous drainage; Low-molecular-weight heparin