The effect of chemical hemodynamic regulation on the survival of arterialized venous flaps

Effect of hirudin on arterialized venous flap survival in rabbits

Arterialized venous flap (AVF) is limited in clinical application because its survival remains inconsistent and its exact survival mechanism is still unclear. Hirudin is an effective thrombin specific inhibitor, which is isolated from the salivary gland secretions of the leech. Our study evaluated the impact of hirudin on the viability of AVFs in rabbits. Thirty-six rabbits were randomly divided into three groups: sham group (physiological perfusion), control group (AVF), and hirudin group (AVF + hirudin). In hirudin group, 20 antithrombin units (ATU) hirudin (2.5 ml) were injected into each flap. In sham group and control group, the same amount of normal saline was injected into each flap. Status of flap survival, water content, vascular perfusion, histopathology, expression of CD34, VEGF, eNOS and HIF-1α were analyzed in each group. Analysis of oxidative stress was performed by measuring the activity of superoxide dismutase (SOD) and malondialdehyde (MDA). Compared with flaps in sham group with physiological perfusion mode, results of survival rate, perfusion status, SOD activity, expression of CD34, VEGF, and eNOS of AVFs in control group were significantly lower, while water content, MDA level and expression of HIF-1α were higher. The flap condition of AVFs injected with hirudin in hirudin group was improved significantly, and the results were similar to sham group. Our findings revealed that hirudin can effectively improve survival of AVF.

A metabolic investigation of arterialized venous flaps in rabbits using mass spectrometry-based metabolomics

An arterialized venous flap (AVF) is an ideal choice of flap to repair wounds. However, the survival of these flaps remains the source of some concern. This study used metabolomic analysis to investigate the mechanisms underlying survival in AVF flaps in order to guide the clinical application of these flaps. Thirty-six male Japanese rabbits were randomly divided into a sham group and an AVF group. They were used for histology and hemodynamic investigations. Three days after surgery, tissue samples were analyzed by mass spectroscopy-based metabolomics. The results of the study revealed a reduction in blood flow, infiltration of inflammatory cells, and necrosis of flaps in the AVF group. In addition, notable changes were evident in the levels of several metabolites in the AVF group, including lactic acid, acetoacetic acid, inositol phosphate, arachidonic acid, and other metabolites. Our results indicate that the AVF group experienced changes in several biological pathways, including energy metabolism, cell membrane stability, and inflammatory response. There is a significant metabolic difference between AVFs and physiological flaps. The dysregulation in certain metabolites may be related to the specific hemodynamics and insufficient energy metabolism of the AVFs.

Effects of arterial blood supply and venous return on multi-territory perforator flap survival

This study aimed to design arterial ischemic and venous congested areas on the same multi-territory perforator flap, assessing the effects of arterial blood supply and venous return on flap survival. Totally 68 rats were randomly divided into the experimental (Exp) and control (Con) groups. In the Exp group, flaps were based on left superficial epigastric artery and right superficial epigastric vein. In the Con group, flaps were based on the left superficial epigastric artery and vein. Immediate postoperative ink-gelatin angiography, epidermal metabolite levels detection, tissue edema measurement, survival rate evaluation in half of the flaps and average microvessel density assessment were performed. Blood in the Exp group flowed through most angiosomes, but only flowed around pedicled vessels in the Con group; metabolite levels of left halves in the Con and Exp groups were comparable with those of right halves. Angiosomes with high water contents occurred in the Exp group. Survival rates of left halves in the Con and Exp groups were higher than those of right halves, and more microvessels were found in the left ventral areas of both groups compared with the right ventral area in the Exp group. These findings revealed that on the same multi-territory perforator flap, arterial blood supply, affected by venous return, is a prerequisite for flap survival.