Colour Doppler ultrasound evaluation of haemodynamic changes in free tram flaps and their donor sites.

Colour Doppler ultrasound (US) was used to measure the blood flow in the donor and recipient arteries as well as in the deep superior epigastric artery of 10 patients having free transverse rectus abdominis myocutaneous (TRAM) flaps. The peak, minimum and mean velocities, the diameter of the vessel, and the resistance index of both the deep superior and inferior epigastric arteries and thoracodorsal arteries were recorded preoperatively and at 4-6 and 15-30 days postoperatively. Colour Doppler US showed increased minimum velocity and decreased resistance index in the pedicle (p < 0.05) throughout the follow-up when compared with the baseline. In the ipsilateral superior epigastric artery the mean and minimum velocities increased (p < 0.05) while the resistance index decreased (p < 0.05) during the first month postoperatively. No changes were recorded in the opposite epigastric arteries or in the control vessel (opposite thoracodorsal artery). In all patients the diameter of the deep inferior epigastric artery was larger than that of the superior epigastric and remained so after the transfer. From the fourth to the thirtieth postoperative day blood flow increased in the free TRAM flap, presumably because of decreased vascular resistance. Blood flow also increased in the superior epigastic artery on the donor side after free TRAM transfer as expected (indicating the delay phenomenon), but harvesting the flap did not affect the circulation in the opposite rectus abdominis muscle. The inferior epigastric arterial system was dominant in all patients.