Technique
A 41-year-old man referred to our hospital with an exertional chest pain. Coronary computed tomography (CT) angiography showed MB located from the mid segment of the LAD to the first diagonal branch (Fig. 1A). Preoperative CAG revealed severe stenosis of LAD at the site of MB during systole (Fig. 2A). FFR at the lesion was 0.72 with 50 γ of dobutamine administration. Medical therapy with beta blocker was initiated, but the symptom did not improve. Since there was no long or deep bridges, minimally invasive surgical unroofing (off-pump and left mini-thoracotomy) was selected for early rehabilitation.
Surgical technique. After general anesthesia and double-lumen endotracheal intubation, the patient was positioned at 30°right lateral decubitus position. A 6-cm incision was made on the 4th intercoastal space. After pericardium was incised anterolaterally, an octopus NUVO stabilizer (Medtronic Inc., Minneapolis, MN, USA) was inserted via 5thintercoastal space on the mid-clavicular line to stabilize the LAD. By using VeriQ system probe (MediStim, Oslo, Norway), we confirmed the location of MB and squeezing of the LAD(Fig. 1B and C). The LAD was buried in the myocardium for 25 mm from the first diagonal branch (Fig. 3A). The epicardium at the MB was dissected with small circular knife blade and fat above the LAD was removed using a Harmonic Scalpel (Ethicon Endo- Surgery, Inc, Somerville, NJ). The MB was resected by using small potts scissors. Intraoperative CAG showed residual squeezing at the peripheral side of the MB. Therefore, additional unroofing was performed and buried LAD was completely exposed (Fig. 3B and C).
Postoperative course was uneventful and CAG showed no residual squeezing of the LAD (Fig. 2B). Postoperative FFR was 0.92 under 50 γ of dobutamine administration. There was no wound trouble of the 6-cm main incision at the left 4th intercoastal space and 1-cm incision for stabilizer at the 5th intercoastal space (Fig. 3D).