Refining our knowledge of macrovascular arteriovenous shunts (MAS): Anatomical and pathological studies

The macrovascular arteriovenous shunt (MAS) connecting the deep inferior epigastric artery (DIEA) and superficial inferior epigastric vein (SIEV) in the abdominal wall has already been identified as an important structure, and further study has been deemed necessary to establish its role and function. Review of CT angiograms (CTA) of 38 female patients was undertaken, by means of analysis of fine-cut axial images and three-dimensional image reconstructions of the cutaneous vasculature of the deep and superficial vasculature. In vivo dissection of the structure was also performed to establish its communications. Lastly, a histopathological analysis was carried out to investigate its intrinsic structure and function. The MAS was identified in both sides of the abdomen in all subjects and the diameter ranges from 0.72 to 2.81 mm with a median diameter of 1.28 mm. In vivo dissection revealed it as a distinct structure connecting the DIEA and SIEV. Pathological analysis showed that it has characteristics of both elastic and muscular arteries, which constitutes a new vessel. These further investigations have yielded a better understanding of the MAS shunt, its position, structure and function. This can be of crucial importance to reconstructive surgeons when raising the DIEP flap.