Effects Of Distal Arterial Supercharging And Distal Venous Superdrainage On The Survival Of Multiterritory Perforator Flaps In Rats

Objective: Which one of the two measures,distal arterial supercharging(DAS)and distal venous superdrainage(DVS),is better to enhance flap survival? No consistent conclusions have been reached.Methods: The multiterritory perforator flap model(11 cm in length and 2.5 cm in width)containing three angiosomes was created on the dorsum of the experimental animals.posterior intercostal(PIC)vessels were isolated and severed,72 healthy male rats were distributed to four groups randomly: DAVS group(distal arteriovenous supercharging group),the thoracodorsal(TD)artery and TD vein were preserved;DAS group(distal arterial supercharging group),the TD vein was cut;DVS group(distal venous superdrainage group),the TD artery was cut;control group,the TD artery and TD vein were cut.On the 7th day after the operation,the dorsal flaps of all rats were photographed under anesthesia and the average flap survival rates were calculated.Flap angiography was used to assess the vascularization of the flap.Hematoxylin and eosin staining was used to evaluate microvascular density,and immunohistochemical staining was used to calculate CD34-positive vessel density.Western blot was used to assess vascular endothelial growth factor(VEGF)level.Superoxide dismutase(SOD)and malondialdehyde(MDA)levels were assessed using specialized commercial kits.Results: On postoperative day 7,the mean flap survival rates were significantly higher in the DAVS and DAS groups relative to the DVS and control groups,and the DVS group had a significantly higher mean flap survival rate compared with the control group.Flap angiography showed that the vascularizations of the flaps in the DAVS and DAS group were the best,followed by the DVS group,while the control group was the worst.Histological analysis revealed that the microvascular densities and CD34-positive vessel densities were significantly higher in the DAVS and DAS groups than in the DVS and control groups,whereas the microvascular densities and CD34-positive microvessel densities were significantly higher in the DVS group than in the control group.The levels of VEGF in the DAVS and DAS groups were significantly higher than that in the DVS and control groups;compared with the control group,the VEGF level in the DVS group was significantly higher.DAVS and DAS groups had higher SOD levels and lower MDA levels compared to the DVS and control groups;compared with the control group,the DVS group had a higher SOD level and a lower MDA level.Conclusion: By using the dorsum multiterritory perforator flap model in the rat,our experimental results suggest that DAS may play a more active role in promoting the survival rate of the multiterritory perforator flap compared to DVS,mainly by enhancing angiogenesis and preventing ischemia-reperfusion injury.Our research provides an important experimental basis for the clinical preference of distal arterial supercharging to promote the survival of large multiterritory perforator flaps.