Postoperative patency of the retrograde internal mammary vein anastomosis in free flap transfer

Abstract

A caudal limb of the internal mammary vein (IMV) can be used as an additional venous drainage route in free flap transfer. However, there remains the possibility that unrecognised occlusion of the retrograde IMV occurs in the early postoperative period due to non-physiologic flow, thus affecting venous drainage. There are no reports regarding the postoperative patency rates of the anastomosed retrograde IMV. This study aimed to clarify the efficacy of the retrograde IMV as an additional venous drainage route in the case of two-vein anastomosis in free flap transfer. We performed a hospital-based prospective case series study to clarify the patency rates of retrograde IMV anastomoses as an additional venous drainage route in cases of two-vein anastomosis in free flap transfer. Both antegrade and retrograde IMV anastomoses were performed in patients who underwent free flap transfer using the IMV as a recipient vein. The postoperative flow vector and peak blood velocity of the retrograde IMV anastomosis were examined using two-dimensional phase contrast magnetic resonance imaging (2D PC-MRI) and colour Doppler imaging. A total of five retrograde IMV anastomoses in five patients were performed in the study period. The postoperative patency rate of the retrograde IMV was 60%. In the patent group, the postoperative peak venous blood velocity of the retrograde IMV was significantly slower than that of the antegrade IMV (4.6 ± 0.5 vs 7.2 ± 0.8 cm s(-1), P < 0.05). We described the postoperative patency rate of retrograde IMV anastomosis in cases of two-vein anastomosis in free flap transfer. Further study is needed to evaluate the reliability of the retrograde IMV as an additional venous drainage route.