The lumbar artery perforator (LAP) flap, which contains excess skin and fat tissue, love handles, that extends from the lower back to upper buttock, may provide an alternate tissue source for autologous breast reconstruction. However, LAP flap use during this procedure frequently requires vessel interposition grafts to correct the short flap pedicle length and mismatched recipient vessel calibre. A 46-year-old patient underwent a right nipple-sparing mastectomy using a lateral approach for ductal carcinoma in situ and immediate LAP flap breast reconstruction. The lateral thoracic vessel served as the recipient vessel, and a lateral thoracic vein interposition graft from the distal remnant was performed to adjust the arterial length and size discrepancy between the recipient lateral thoracic artery and pedicle artery. This procedure facilitates microsurgical anastomosis and medialisation of LAP flap to make a natural decollete line and create a cleavage for the reconstructed breast.