The effects of interrupted simple versus horizontal mattress sutures and of the internal diameter of the arterial pedicle at the level of the anastomosis on rat epigastric flap perfusion were investigated. In the first group, a microclip was applied to the femoral artery for 30 minutes. In the second group, the artery was cut, and a classic 7- to 8-suture microarterial end-to-end anastomosis was performed. In the third group, the artery was cut, and a microarterial end-to-end anastomosis with 3 horizontal mattress sutures at 120-degree intervals was performed. Perfusion was measured using a laser Doppler flowmeter (Periflux 2B, Perimed, Sweden) at 3 zones of the flap at 30 and 60 minutes and at 21 days after the procedure. Internal vascular diameters were measured histopathologically. Perfusion was better in the control group than in the experimental groups. However, the internal vascular diameters were greater with the classic method than with the new method, and the perfusion did not differ statistically in the anastomosis groups. In conclusion, even when significant narrowing develops at the anastomosis, flap viability is not affected.