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 ec ho color-flow Doppler device. Twenty-eight patients who underwent brea st reconstruction with a TRAM flap in our hospitals were analyzed. Eig hteen of them underwent selective delay 1 month before the major surgi cal procedure, and of them, 15 completed the reconstructive procedure. Ten patients were used as a control group and underwent TRAM flap bre ast reconstruction without selective delay. Cutaneous blood flow in th e TRAM flaps was measured in 20 patients with a laser-Doppler flowmete r, and measurements were taken before, during, and after the surgical procedure, following a standardized protocol, as in Tuominen's origina l 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 e pigastric vessels. Compared with the standard TRAM flap, blood flow in the delayed flaps (10 patients) seemed to be more stable, without fal ling 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, SE M 9.58 percent, standard deviation 30.3 percent) on the axial side. Du ring phase 4 (cutting the rectus muscles), blood flow values reached 1 15.0 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 axi al side. In order to obtain further hemodynamic data, 10 patients who underwent selective vascular delay 1 month prior to breast reconstruct ion with a delayed TRAM flap in our hospitals were then studied by mea ns of an echo color-flow Doppler device. Two of these patients also ha d been studied with the laser-Doppler flowmeter. Superior epigastric a rtery diameter (in millimeters) and resistivity (expressed as Pourcelo t's index) a ere 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 ev er patient an increase in the superior epigastric artery diameter and a decrease in the resistivity index were observed, and this was statis tically significant. In the nonirradiated patients, the increase in th e average diameter of the superior epigastric artery was 98.1 percent, and the average resistivity index decrease was 14.1 percent. In the i rradiated patients, the increase in the average diameter of the superi or epigastric artery was 35.5 percent, and the average resistivity ind ex decrease was 29.8 percent. In conclusion. laser-Doppler flowmeter e valuations 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-now Doppler indicates that the basis fo r the increase in the vascular territory of the super for epigastric a rtery caused by the delay maneuver is an increase in the superior epig astric artery diameter, always accompanied by a decrease in the resist ivity index. Two different mechanisms seem to us to be related to thes e modifications in the blood circulation. In the non-irradiated patien ts, superior epigastric artery dilation prevails, whereas in the irrad iated patients, a decrease in the resistivity index is the dominant me chanism of compensation. These hemodynamic findings well support the d ecrease in flap necrosis reported in our series (standard TRAM: 30 per cent; delayed TRAM: 7.1 percent).