Comparative study of isovolemic hemodilution with 3% albumin, dextran-40, and prophylactic enoxaparin (LMWH) on thrombus formation at venous microanastomosis in rats

Abstract

The objective of the present investigation was to compare the effect of isovolemic hemodilution with 3% albumin, dextran-40, and enoxaparin on the prevention of thrombosis in femoral vein microanastomosis using an experimental model in rats. Forty male Wistar rats were allocated into four groups: group 1, control, thrombogenic model without previous treatment; group 2, hemodiluted, thrombogenic model with previous hemodilution; group 3, dextran-40, thrombogenic model with dextran infusion (10 ml/kg), and group 4, enoxaparin, thrombogenic model with administration of enoxaparin (0.5 mg/kg/day). Hemostatic parameters, hematologic examinations, patency of anastomosis, and histopathological examination were evaluated. The hemostatic parameters were similar in the four groups studied. Group hemodiluted, dextran-40, and enoxaparin showed significantly reduced number of red blood cells and platelets as compared with the control group. The hemodilution significantly increased the patency rates of the vein at 20 min and 48 h. Dextran-40 and enoxaparin improved the patency of the vein only at 20 min, but failed to show a significant increase in the final patency at 48 h. After 48 h, the rate of venous thrombosis, as evaluated microscopically, was significantly decreased in hemodiluted animals (1/8) as compared with controls (10/10); in rats treated with dextran-40 (7/10) and enoxaparin (5/10) the rate of venous thrombosis was significantly higher as compared with rats of the group hemodiluted. Based on these observations, it can be concluded that hemodilution with albumin 3% was a safe and more adequate procedure than the use of the schemes of administration of dextran-40 and enoxaparin used in this study to prevent thrombus formation at femoral vein microanastomosis in rats. Since hemodilution promotes reduction in blood viscosity and in erythrocyte and platelet aggregation as well as dilution of the coagulation factors themselves, its use could provide better microcirculatory blood perfusion, decreasing the risk of thrombosis, and making possible safer microsurgical procedures.

Effect of Previous Irradiation on Vascular Thrombosis of Microsurgical Anastomosis: A Preclinical Study in Rats

“…Microsurgical anastomoses are largely technically dependent; however, there exists a finite rate of failure, with often devastating consequences, such as venous thrombosis, the most frequent complication. 38–40,50–58 We could not confirm that there were not mechanical traumas associated with the repeated number of attempts applied to the irradiated vessels. Repetitive attempts of vascular anastomosis are traumatic and should be performed as gently and infrequently as possible.…”

Intraoperative perfusion management impacts postoperative outcomes: An analysis of 682 autologous breast reconstruction patients

“…19 It is plausible that higher rates of resuscitation can potentially lead to some of the suggested benefits of hemodilution, which including the reduction of stasis, reduced red cell and platelet aggregation and dilution of clotting factors. 20 True over-resuscitation; however, can lead to medical complications and even increased flap complications. 3 No significant increase in medical complications was noted in our patients with higher rates of resuscitation.…”

Microsurgical Reconstruction of Lower Extremity in Homozygosity of C677t MTHFR Gene Mutation: Case Report and Review of the Literature

“…The efficacy of normovolemic and hypervolemic haemodilution in microsurgical reconstruction is still debated, and in this regard, literature lacks randomized, prospective studies 22 . Nonetheless, experimental studies have proven the benefits of haemodilution in reducing the rate of thrombotic complications in free flap surgery, suggesting its potential benefits on free flap survival [23][24][25][26] . As regards fluid therapy protocols, crystalloids or a combination of colloidal and crystalloid solutions are commonly utilized for hemodilution.…”