The Effect of Hemodynamic Remodeling on the Survival of Arterialized Venous Flaps

Abstract

ObjectiveTo evaluate the effect of hemodynamic remodeling on the survival status of the arterialized venous flaps (AVFs) and investigate the mechanism of this procedure.Materials and MethodsTwo 7 x 9 cm skin flaps in each rabbit (n=36) were designed symmetrically in the abdomen. The thoracoepigastric pedicle and one femoral artery were used as vascular sources. Four groups were included: Composite skin grafts group and arterial perfusion group were designed in one rabbit; AVF group and hemodynamic remodeling group by ligation of the thoracoepigastric vein in the middle were outlined in another rabbit. Flap viability, status of vascular perfusion and microvasculature, levels of epidermal metabolite and water content in each group were assessed.ResultsHighly congested veins and simple trunk veins were found using angiography in the AVF group; while a fairly uniform staining and plenty of small vessels were observed in the hemodynamic remodeling group. The metabolite levels of the remodeling group are comparable with those in the arterial perfusion group. There was no statistically significant difference in the percentage of flap survival between the arterial perfusion group and hemodynamic remodeling group; however, significant difference was seen between the AVF group and the hemodynamic remodeling group.ConclusionsUnder the integrated perfusion mode, the AVFs are in an over-perfusion and non-physiological hemodynamic state, resulting in unreliability and unpredictability in flap survival; under the separated perfusion mode produced by remodeling, a physiological-like circulation will be created and therefore, better flap survival can be expected.

The complicated role of venous drainage on the survival of arterialized venous flaps

“…The reasons why this strategy does not work efficiently for AVFs still remain elusive. In our previous study [10], we found that consistent venous congestion occurred in the peripheral area in a flow-through type of AVF and its hemodynamic feature is characterized as an integrated perfusion mode. Under this perfusion mode, the pressure in the central arterialized vein was high and the pressure difference between the two ends was subtle.…”

“…This flap differs from the traditional flap because it is perfused only through the venous system [9, 10]. Several survival mechanisms regarding this kind of flaps, such as the theories of “A-V shunting”[11],“reverse flow”[12] and “capillary bypass”[13], have been brought forward, yet no consensus on its exact mechanism has been comprehensively addressed.…”

“…As described in detail in our previous study [1, 10], adult white Japanese rabbits of both sexes, weighing between 3.5 and 4 kg, were used. All experiments were approved by the Institutional Animal Care and Use Committee of Wenzhou Medical University and carried out according to the ethical approval and the National Research Council's guidelines for the care and use of laboratory animals.…”

“…The animal model was modified based on our previous study [1, 10]. In brief, a 10 × 8 cm (length x width) skin flap was designed symmetrically along the middle line of the abdomen; the flap was tailored including the epidermis, dermis, subcutaneous tissue, and the panniculus carnosis.…”

“…As described in detail in our previous study [10], the flap samples (1 × 1 cm 2 ) were harvested in the center of the flap (Figure 1, the black square) and dried with a stencil for analysis and the wet weight of the sample was obtained by a precision electronic scale. The flap was then placed in a drying oven and maintained for 24 hours at 65°C and the dry weight of the flap was measured with the same precision scale.…”