Arterial Supercharging Is More Beneficial to Flap Survival Due to Quadruple Dilation of Venules

Background: "Choke vessels" are communicating conduits between adjacent perforasomes in the skin. Most researches focus mainly on the arterial aspect of the "choke vessels" and neglect the venous aspect, an imbalance needed to be addressed. Materials and methods: The study was divided into parts I, II, and III. Part I was for observation of the vascular morphological evolution in the choke zone after flap harvest in rats. Part II was for determination of the importance of the dilation of the arterial and venous components of "choke vessels" by preserving the iliolumbar artery (ILA group) or vein (ILV group). A laser Doppler flowmeter and a speckle flow imaging system were adopted for monitoring the hemodynamic impact caused by the different manipulation. Part III was for corroboration of part II by manipulation of other vessels. Results: In part I, the arteries and veins between the iliolumbar and intercostal perforasomes underwent modest dilation, whereas the venules between the veins nearly quadrupled in diameter. In part II, flaps in the ILA group were much more intensive in blood perfusion than flaps in the ILV group. The flap necrosis rate was 0.31 +/- 0.07 in the ILV group, being significantly larger than 0.10 +/- 0.03 in the ILA group. Part III confirmed that venous superdrainage is less efficacious in reducing flap necrosis than arterial supercharging, in which the position of the additional artery was far more important than the diameter. Conclusions: The extensive dilation of the venous component of choke vessels makes a more potent compensatory role for venous drainage after flap harvest, indicating arterial supercharging is better in augmenting flap viability than venous superdrainage. (C) 2019 Elsevier Inc. All rights reserved.