Indices of obesity and behaviour of the pedicled tram flap in breast reconstruction.

The association between obesity and the outcome of pedicled transverse rectus abdominis musculocutaneous (TRAM) flaps was studied in 12 patients. Obesity was assessed preoperatively by body mass index (BMI) and waist:hip circumference ratio (WHCR). The thickness of the abdominal fat and muscles was measured preoperatively with ultrasonography on the abdomen and during the nine postoperative months on the flap. Marginal or fat necrosis was more common among patients with lower body type fat distribution (WHCR less than 0.80) than in patients with medium or upper body type fat distribution. BMI and abdominal muscle and fat thicknesses were not associated with marginal or fat necrosis of the flaps. We conclude that lower body (female type) fat distribution may be associated with marginal cutaneous or fat necrosis in pedicled TRAM flaps.

The effect of felodipine on endothelin-1 levels, peripheral vasoconstriction and flap survival during microvascular breast reconstruction.

Endothelin-1 (ET-1) may contribute to vasoconstriction and flap blood flow during microvascular surgery. Calcium antagonists have suppressed ET-1 release in some studies. The effect of 5 mg of felodipine, a vasodilating calcium antagonist, administered the evening and morning before a microvascular TRAM (transverse rectus abdominis musculocutaneous) flap breast reconstruction, on perioperative plasma ET-1 concentrations, peripheral temperature gradient (Tgrad), rectal temperature (Trect), flap skin blood flow with transcutaneous oxygen tension (ptcO2), heart rate (HR) and mean arterial pressure (MAP) was evaluated in this clinical, randomised, double blind, prospective study. Felodipine did not cause any statistically significant changes in ET-1 levels, Tgrad, Trect, Ptc O2, flap survival or pre- or intraoperative MAP. HR was significantly higher in the felodipine group before induction and at 10 min postoperatively. We conclude that in patients undergoing a microvascular TRAM flap breast reconstruction, preoperatively administered felodipine has no effect on perioperative ET-1 levels, temperature changes, or flap skin blood flow.

Perioperative plasma endothelin-1 concentrations and vasoconstriction during prolonged plastic surgical procedures.

The role of endothelin-1, a potent vasoconstrictor released by vascular endothelium, in the vasoconstriction that develops after prolonged operations is not clear. This study was performed in order to determine if there was any relationship between endothelin-1 and the degree of vasoconstriction during prolonged plastic surgery. Plasma concentrations of endothelin-1, skin-forearm temperature gradient (Tgrad), rectal temperature, mean arterial pressure (MAP) and heart rate (HR) were measured at nine predetermined times before, during and after operation in nine women undergoing breast reconstruction with a pedicled transverse rectus abdominis musculocutaneous flap. Development of cutaneous or fat necrosis of the flap was assessed clinically and with ultrasound. Concentrations of endothelin-1 before induction were increased (median 8.9 (25-75% quartiles 5.5-12.5) pg ml-1). During operation they were approximately 3 pg ml-1 and after operation approximately 5 pg ml-1. Tgrad was approximately 4 degrees C before induction and after operation, indicating marked vasoconstriction; during operation it was about zero, indicating vasodilatation. There was a statistically significant correlation between endothelin-1 concentrations and Tgrad (Spearman non-linear correlation) (r = 0.32, P = 0.004) and between endothelin-1 and MAP (r = 0.25, P = 0.02), but not between endothelin-1 and HR or development of minor cutaneous or fat necrosis of the flap (five patients). We conclude that increased plasma concentration of endothelin-1 is associated with the extent of peripheral vasoconstriction.

Cutaneous blood flow in the free TRAM flap.

According to clinical studies there are fewer circulatory complications with the free TRAM flap than with the pedicled TRAM flap. In this haemodynamic study, we measured perioperative cutaneous blood flow in 11 free TRAM flaps with laser Doppler flowmetry (LDF) and transcutaneous oxygen tension (ptcO2). We also studied 4 pedicled TRAM flaps with an additional microvascular anastomosis. Our results suggest that skin blood flow in the free TRAM flap is superior compared to our previously presented results of the pedicled TRAM flaps, and also superior to pedicled TRAM flaps with additional microvascular anastomoses of the inferior epigastric vessels to "supercharge" them.

Cutaneous blood flow in the TRAM flap.

Changes in the cutaneous blood flow of the pedicled TRAM flap for breast reconstruction were studied in 15 patients with laser Doppler flowmetry (LDF) and transcutaneous oxygen tension (ptcO2). One patient was excluded from the study. The LDF value increased to 127 +/- 15% of the base line on the random and to 151 +/- 13% (p less than 0.01) on the axial side after dissection of the random side of the flap. Ligation of the deep inferior epigastric artery caused a decrease to 57 +/- 8% (p less than 0.001) on the random and to 78 +/- 11% on the axial side. The random side ptcO2 decreased from 48 +/- 2 mmHg [6.4 +/- 0.3 kPa] to 17 +/- 5 mmHg [2.3 +/- 0.7 kPa] (p less than 0.001) after dissection of the flap and remained near zero for one week. Eight patients developed minor cutaneous necrosis on the random side, probably because the superior epigastric system could not adequately nourish the TRAM flap. Low LDF and ptcO2 values after pedicle ligation and a negative response to oxygen stimulation predicted skin necrosis.