Lateral MIDCAB grafting via limited posterior thoracotomy

Minimally invasive direct coronary artery bypass (MIDCAB) is a technique for coronary artery bypass grafting performed under direct vision without sternotomy or cardiopulmonary bypass. The approach has been used principally for primary single vessel grafting of the anterior or inferior coronary circulation. This initial experience presents a new lateral technique for patients with isolated circumflex coronary disease which can be used for both primary and reoperative revascularization with either saphenous vein or a free radial artery conduit.

Lateral MIDCAB grafting of the circumflex coronary circulation was accomplished over a 33 month period at a single center using saphenous vein or free radial artery as the bypass conduit. Through a limited posterior thoracotomy, the lung is deflated and reflected superiorly. The pericardium is opened below the phrenic nerve to expose an obtuse marginal branch of the circumflex coronary artery. After heparinization, the coronary artery is temporarily occluded proximally and distally with local immobilization and an arteriotomy is performed. The distal anastomosis with running suture is followed by the proximal anastomosis on the descending aorta below the hilum of the lung using a side-biting clamp and radiopaque marker. Intraoperative transit time ultrasound flow measurements confirm adequate graft flow before wound closure.

To date, 19 patients have undergone this procedure with a mean follow-up of 12 months. A total of 12 patients received saphenous vein grafts and 7 patients received radial artery grafts. There was one death from arrhythmia on postoperative day 9. There was one elective conversion to conventional sternotomy due to inadequate exposure. Graft flows averaged 33.3 cc/min (range 5-87) and the mean postoperative length of stay was 4.5 days; 4 patients underwent recatheterization; 1 had graft occlusion and 2 received late postoperative catheter-based interventions. All patients are currently free of symptoms.

Lateral MIDCAB grafting provides focused revascularization to the circumflex distribution in both primary and reoperative settings. This approach avoids the hazards of resternotomy, eliminates cardiopulmonary bypass, and hastens postoperative recovery. These early results suggest the technique is effective at relieving symptoms and minimizing perioperative morbidity. Further experience at multiple centers will serve to define the ultimate capabilities of this new approach.