Do superficial epigastric veins of rats have valves?

The rat is a good model for experimental studies on the haemodynamic patter ns of free-flap transfer but models involving the superficial epigastric ve in have not been supported by the demonstration of the anatomical presence or absence of valves inside it. We performed a morphological study to asses s whether or not valves are present inside the superficial epigastric vein of the rat. Segments of superficial epigastric veins were explanted from fi fteen Sprague-Dawley rats. The lumen was studied with scanning electron mic roscopy after longitudinal or transverse incision of the venous walls. No v alves were detected and we saw no evidence of their accidental removal. As most human veins do have valves, the clinical implications of haemodynamic data on reverse-flow island flaps obtained in rats must be considered very carefully. (C) 2001 The British Association of Plastic Surgeons.