The Beneficial Effect of Dextran on Anastomotic Patency and Flap Survival a Strongly Thrombogenic Model

Abstract

Dextran lowers the probability of thrombus formation, by reducing platelet aggregation and adhesion and by increasing fibrinolysis. All studies to date using dextran for microvascular reconstruction have examined only short-term (1 to 2 hr) patency in isolated vessels. The current study used an established thrombotic model (inverted sleeve interposition graft), to investigate the effect of dextran on the long-term survival of pedicle flaps. A6- x 3-cm epigastric flap was elevated. A 2-mm inverted sleeve interposition graft was placed on the artery side of the pedicle by microvascular techniques. One group received dextran (17 cc/kg) 2 hr preoperatively and every 6 hr postoperatively for the next 72 hr. A control group received saline on the same schedule. Survival was assessed on postoperative day 7, at which time necrosis was obvious. Several parameters (clotting studies and electron microscopy) were studied to characterize the phenomenon more clearly. Only 25 percent of saline-treated flaps survived (2/8), while all dextran-treated flaps survived (7/7) (p less than 0.02, Fisher exact test). Thus, dextran allowed flaps to survive by preventing thrombus formation, despite a strong thrombogenic focus.

Ischemia/reperfusion injury in microvascular surgery

“…It is a specific inhibitor of thrombin. 39 A similar model comparing dextran with other agents failed to show significant improvement in skin flap survival for dextran compared with control animals. In an experimental study using a rabbit arterial crush model, high and low doses of hirudin and heparin were compared.…”

“…Hirudin is the anticoagulant component found in the saliva of leaches. 38,39 Experimental results with dextran have varied. Although it has been tested both systemically and topically, there is particular hope that the topical use of the agent would decrease vascular thrombosis while avoiding systemic anticoagulation.…”

Evidence to Support Controversy in Microsurgery

“…Dextran had been used as an antithrombotic agent to decrease red blood cell aggregation (Level V Evidence). 151 Disa et al, in a prospective randomized series, observed no effect on flap survival comparing dextran to aspirin (Level I Evidence). 152 However, in the same study, dextran led to a 3.9-to 7.2-fold increase in systemic complications such as congestive heart failure, myocardial infarction, pulmonary edema, pleural effusion, and pneumonia.…”

Development of a gut perfusion model as an alternative to the use of live fish

“…Several authors have reported that using dextran can prolong the viability of the transplants because it is able to raise the colloidal pressure and hence prevent oedema. Dextran has additionally been shown to aid the prevention of thrombus formation at the intima of small blood vessels, thereby improving circulation (Wolfort et al 1992, Salemark et al 1995, Wang et al 2004.…”