Norepinephrine preserved flap blood flow compared to phenylephrine in free transverse rectus abdominis myocutaneous flap breast reconstruction surgery: A randomized pilot study

Abstract

Vasopressors are used in up to 85% of cases during free flap surgery. However, their use is still debated with concerns of vasoconstriction-related complications, with rates up to 53% in minor cases. We investigated the effects of vasopressors on flap blood flow during free flap breast reconstruction surgery. We hypothesized that norepinephrine may preserve flap perfusion better than phenylephrine during free flap transfer. A randomized pilot study was performed in patients undergoing free transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction. Patients with peripheral artery disease, allergies to study drugs, previous abdominal operations, left ventricular dysfunction, or uncontrolled arrhythmias were excluded. Twenty patients were randomized to receive either norepinephrine (0.03-0.10µg/kg/min) or phenylephrine (0.42-1.25µg/kg/min) (each n=10) to maintain a mean arterial pressure of 65-80mmHg. The primary outcome was differences in mean blood flow (MBF) and pulsatility index (PI) of flap vessels after anastomosis measured using transit time flowmetry in the two groups. Secondary outcomes included flap loss, necrosis, thrombosis, wound infection, and reoperation within 7 days postoperatively. After anastomosis, MBF showed no significant change in the norepinephrine group (mean difference, -9.4±14.2mL/min; p=0.082), whereas it was reduced in the phenylephrine group (-7.9±8.2mL/min; p=0.021). PI did not change in either group (0.4±1.0 and 1.3±3.1 in the norepinephrine and phenylephrine groups; p=0.285 and 0.252, respectively). There were no differences in secondary outcomes between the groups. During free TRAM flap breast reconstruction, norepinephrine seems to preserve flap perfusion compared to phenylephrine. However, further validation studies are required.