A hemodynamic approach to clinical results in the TRAM flap after selective delay

The delay phenomenon in the transverse rectus abdominis myocutaneous (TRAM) flap was studied by means of a laser-Doppler flowmeter and an echo color-flow Doppler device. Twenty-eight patients who underwent breast reconstruction with a TRAM flap in our hospitals were analyzed. Eighteen of them underwent selective delay 1 month before the major surgical procedure, and of them, 15 completed the reconstructive procedure. Ten patients were used as a control group and underwent TRAM flap breast reconstruction without selective delay. Cutaneous blood flow in the TRAM flaps was measured in 20 patients with a laser-Doppler flowmeter, and measurements were taken before, during, and after the surgical procedure, following a standardized protocol, as in Tuominen's original scheme. Variations in the cutaneous blood flow in the standard TRAM flap (10 patients) confirmed data obtained from the literature, i.e., an increase when elevating the cutaneous and subcutaneous parts of the flap and a decrease when ligating the deep inferior and superficial epigastric vessels. Compared with the standard TRAM flap, blood flow in the delayed flaps (10 patients) seemed to be more stable, without falling under the baseline. When elevating the cutaneous and subcutaneous parts of the flap (phase 3), blood flow values reached 120.2 percent (SEM 46.8 percent) on the random side and 131.6 percent (p < 0.009, SEM 9.58 percent, standard deviation 30.3 percent) on the axial side. During phase 4 (cutting the rectus muscles), blood flow values reached 115.0 percent (SEM 40.5 percent) on the random side and 102.8 percent (SEM 1.2 percent, standard deviation 3.8 percent, p < 0.049) on the axial side. In order to obtain further hemodynamic data, 10 patients who underwent selective vascular delay 1 month prior to breast reconstruction with a delayed TRAM flap in our hospitals were then studied by means of an echo color-flow Doppler device. Two of these patients also had been studied with the laser-Doppler flowmeter. Superior epigastric artery diameter (in millimeters) and resistivity (expressed as Pourcelot's index) were measured before and after selective delay of the deep and superficial inferior epigastric vessels, following a standardized protocol. Measurements were taken with 7.5- and 10-MHz linear probes at a point located after the origin of the costomarginal artery. In every patient an increase in the superior epigastric artery diameter and a decrease in the resistivity index were observed, and this was statistically significant. In the nonirradiated patients, the increase in the average diameter of the superior epigastric artery was 98.1 percent, and the average resistivity index decrease was 14.1 percent. In the irradiated patients, the increase in the average diameter of the superior epigastric artery was 35.5 percent, and the average resistivity index decrease was 29.8 percent. In conclusion, laser-Doppler flowmeter evaluations show that cutaneous blood flow in the delayed flap is more constant and undergoes fewer variations than that in the standard TRAM flap. In addition, echo color-flow Doppler indicates that the basis for the increase in the vascular territory of the superior epigastric artery caused by the delay maneuver is an increase in the superior epigastric artery diameter, always accompanied by a decrease in the resistivity index. Two different mechanisms seem to us to be related to these modifications in the blood circulation. In the nonirradiated patients, superior epigastric artery dilation prevails, whereas in the irradiated patients, a decrease in the resistivity index is the dominant mechanism of compensation. These hemodynamic findings well support the decrease in flap necrosis reported in our series (standard TRAM: 30 percent; delayed TRAM: 7.1 percent).