Operative technique
Surgical approach was at the discretion of the operating surgeon. Routine chest computed tomography was not obtained. Cardioplegia was with high potassium 4:1 blood: crystalloid cardioplegia until July 2014, after which time, cold Del Nido cardioplegia was used. Moderate hypothermia (32° C) was used in all cases.
In the ST group, conventional median sternotomy, ascending aorta and bicaval cannulation, and antegrade cardioplegia catheters were used (coronary sinus catheters are no longer placed routinely). In the RAT group, a small right anterior thoracotomy was made in the fifth intercostal space. Double lumen endotracheal intubation routine. Peripheral cannulation was preferentially utilized. Pericardial retraction sutures were placed and secured on protective red rubber “bumpers” on the chest wall. A left ventricular vent was inserted through the right superior pulmonary vein and tunneled through the chest wall. After MVr, two 32-French chest drains were placed in the mediastinal and pericardial spaces for postoperative drainage. The intercostal space was approximated with heavy suture. Use of subpleural pain catheters was at the discretion of the surgeon.
MV exposure and the approach to MVr was similar in both groups. The MV was typically accessed via the interatrial sulcus, although transseptal and left atrial dome approaches were also utilized. Posterior leaflet MVr generally involved resection of the diseased segment, annular plication and reconstruction of the posterior leaflet. The anterior leaflet was repaired by the placement of Gore-Tex neochordae (W.L. Gore & Associates, Inc., Flagstaff, AZ, USA) or resection and reconstruction. A true-sized, partial posterior MV annuloplasty was primarily utilized.