A simplified surgical approach for aortic valve replacement after previous coronary artery bypass grafting using upper mini-sternotomy approach

We read with great interest the article ‘A simplified surgical approach for aortic valve replacement after previous coronary artery bypass grafting’ by Vistarini and colleagues [1]. Aortic valve replacement (AVR) following a coronary artery bypass grafting (CABG) is becoming more frequent and is a challenging operation. The crucial issue remains the surgical approach and cardiac protection, attempting to simplify a problematic procedure. From their experience, the operating quickness and a simplified approach (open IMA technique, anterograde cardioplegia, mild-to-moderate hypothermia and minimal dissection of the mediastinal structures) represent fundamental choices to perform this type of surgery easily, safely and with optimal results. In our department, from February 1997 to December 2007, we used the upper mini-sternotomy (UMS) approach in 1126 patients undergoing a variety of surgical procedures [2]. Out of 125 re-do procedures performed, 24 patients (19%) had a previous CABG. Once the sternum was re-entered, dissection from adhesions was limited to the structure directly involved in the procedure or necessary for venous cannulation. Cardiopulmonary bypass (CPB) was normally instituted between the right atrium and the ascending aorta. In selected cases (for presumed high risk of re-entry problems), a peripheral venous and arterial cannulation of the femoral vessels was preferred and CPB was started before approaching re-do sternotomy, in order to decompress the heart. The patent left internal mammary artery graft was not dissected (with the exception of three cases of strong adhesion to the ascending aorta) and was never clamped. We also tried to avoid as much as possible dissection and manipulation of the saphenous graft. Using the UMS approach the distal part of the grafts and the ventricles are not involved in the procedure, because they are located under the inferior part of the sternum, thus reducing the dissection of the heart, the operating time and blood loss. All patients underwent CPB with a mild-to-moderate systemic hypothermia (mean temperature: 30.3 ± 2.3 °C). The left ventricle venting through the right superior pulmonary vein was not used routinely and blood was removed directly from the aorta. Myocardial protection was obtained using cold crystalloid cardioplegia, delivered through the aortic root and with selective cannulation of the coronary ostia. At the beginning of our experience, we had three cases of re-entry problems: two accidental damages from a previous coronary graft and one right internal mammary artery (RIMA) injury, requiring conversion to full sternotomy. In our series we registered one case of perioperative myocardial infarction and two cases of postoperative low cardiac output, which is comparable with the results of other groups [3,4]. We report an early mortality of 12.5% and a 5-year survival of 76%. These results also are in line with those reported by other authors using other techniques [3–5]. In conclusion, this type of surgical approach may be helpful for patients receiving AVR after previous CABG, and a simplified surgical strategy can be associated with a minimally invasive approach without compromising a satisfactory outcome.