Median sternotomy, cardiopulmonary bypass and various degrees of systemic hypothermia are used in classic surgery to repair or replace cardiac valves. Minimally invasive, or “key hole,” surgery has recently been used to minimize surgical trauma and shorten the hospital stay and rehabilitation period. Cohn and associates compared the quality of valve replacement and repair through a minimally invasive incision with that of standard median sternotomy.
Patients with concomitant major coronary artery disease were excluded from the analysis. Forty-one patients who underwent aortic valve surgery and 43 patients who underwent mitral valve surgery through minimally invasive incisions were studied prospectively. In addition, the authors compared cost, length of hospital stay and need for rehabilitation services after hospital discharge in the first 50 patients who had undergone minimal procedures with those same parameters in 50 patients who had undergone standard valve replacement through a median sternotomy.
The surgical mortality was 5 percent (two of 41 patients) for aortic valve surgery and zero for mitral valve surgery. The two deaths occurred in class IV patients (one death was associated with liver failure and one with arrhythmia). No infections of the thoracic incision developed. One patient required conversion to sternotomy after aortic valve replacement because of a coronary sinus injury related to use of a catheter. There was one postoperative death. Other significant morbidity included one transient ischemic attack and one cerebrovascular accident.
Patients improved by at least two functional classes in the New York Heart Association classification. Less pain, less pain medication and a significantly faster return to normal activity were documented in the patients who had minimally invasive incisions, compared with patients who had undergone similar procedures with median sternotomy.
The authors note that a disadvantage of the minimally invasive approach is the need to use the femoral area for cannulation and perfusion in many patients. The authors note that retrograde dissection may occur. Thus, the thoracic aorta is monitored for severe atherosclerotic changes before using the technique. The rate of groin complications was 8 percent (seven of 84 patients); three had superficial infections, and four required intraoperative arterial reconstruction.
The authors conclude that the quality of cardiac valve surgery with a minimally invasive incision appears to be equal to that of the sternotomy approach. A minimally invasive incision, however, may not be as useful in extremely ill patients with a high degree of risk and potential morbidity. The minimally invasive approach requires longer ischemia and bypass times.