The acute and delayed effects of hydrostatic dilation on rat femoral arteries

The technique of intraoperative vessel dilation is sometimes used to facilitate microvascular anastomosis and prevent vasospasm. Although this technique is not new, its application has not gained widespread acceptance mainly due to concerns raised about potential damage to the vessels acutely and during the postoperative period, leading to decreased vessel patency. The goal of this study was to determine the acute and delayed histologic effects of hydrostatic dilation on rat femoral arteries and to compare the response of dilated arteries to vasodilating and vasoconstricting agents. The femoral arteries in 22 rats were used in 2 experimental groups; 9 in the acute group and 13 in the delayed group. Six animals served as controls. After the vessels were exposed, a microcatheter was inserted into a segment of the vessel that had been isolated between 2 vessel clamps. Saline was infused into the artery until a pressure of 300 mm Hg was attained and then maintained for 60 seconds. In the acute group, the animals were euthanized at the end of the dilation, while in the delayed group the animals were euthanized 24 hours later. Hydrostatic dilation of rat femoral arteries was found to increased vessel diameter acutely, with subsequent relief and prevention of vasospasm during the ensuing 24 hours. Histologically, there was no increased damage of the vessel walls in the dilated vessels compared with control vessels. Based on the data reported in this study, hydrostatic dilation of rat microvessels appears to be safe and may be used to technically facilitate microanastomoses and decrease vasospasm.