Introduction br Minimally invasive mitral valve surgery

Introduction
Minimally invasive mitral valve surgery Mitral valve surgery has been the procedure most greatly influenced by minimally invasive approaches. Several pioneers, like Navia and Cosgrove, Cohn et al, Chitwood et al, and Carpentier et al independently described minimally invasive mitral valve surgery after mid-1990. Those operations were performed through parasternal, hemisternotomy, and minithoracotomy approaches. The most popular approach for minimally invasive mitral valve surgery in current practice is through a right minithoracotomy. Peripheral cannulation is usually required to further reduce the chest incision and maximize the operative space. Femoral vessel cannulation using the puncture method and Seldinger\'s technique is common practice. For better drainage and reduction of intracardiac residual blood, vacuum-assisted venous drainage is frequently employed. Superior vena cava cannulation via the right internal jugular vein is applied for better drainage or exclusion of both venae cavae during the right neuronal nitric oxide synthase procedures. Although the heart locates mostly in a left deviated position, right thoracotomy is the incision of choice for easier exposure, better visualization, and the ease of aortic manipulation. The chest incision usually locates along the breast contour or pectoralis major muscle margin and is made more laterally to the right nipple for better cosmesis. The right pleural cavity is usually entered via the fourth intercostal space. Aortic cross-clamping can be achieved by an endoaortic clamp or transthoracic clamp. The transthoracic clamp has the advantages of less expense, and easier manipulation and reproducibility at the expense of one additional chest stab incision. Cardioplegic arrest is critical for small-incision procedures. Repetitive administration of cardioplegic solution is usually required for potentially prolonged procedures. Aortic root venting catheters, miniports, and pigtail catheters can be used for this purpose. They also provide the advantage of deairing after the completion of intracardiac procedures. Application of carbon dioxide in the operative field has been common practice. It enhances the dissolution and reduces the risk of air embolism. Exposure of the mitral valve requires specialized instruments. Most of these need assembly inside the pleural cavity. Inside the pleural cavity, the surgeon sees the details by direct vision or through the endoscope. Direct vision implies larger incision and the use of a rib retractor, which may increase postoperative pain. An endoscope has the advantages of magnification and video broadcasting. It requires an additional port and enables the cardiac surgery through a slit intercostal incision, a so-called non-rib spreading approach. Both repair and replacement techniques are similar to conventional concepts founded by Carpentier, but through extended length instruments. The hypothesized benefits of minimally invasive mitral surgery consist of decreased length of stay, decreased surgical trauma, reduced pain, improved patient satisfaction, and potentially reduced hospital resource utilization. These advantages, however, have often been challenged by increased operative times, decreased surgical exposure, and a significant learning curve. However, over the past 10 years, more outcome articles have been published in the literature. No studies to date have demonstrated a significant difference in mortality rates between minimally invasive and sternotomy mitral valve surgery. At our hospital, we have observed better outcomes in mean postoperative ventilation time and mortality rates between sternotomy and minithoracotomy mitral valve surgery. The Society of Thoracic Surgeons database showed that, after risk adjustment, there was a lower probability of postoperative atrial fibrillation, perioperative red blood cell and platelet transfusion, and overall major morbidity or mortality. However, stroke was more common among less-invasive mitral valve surgery patients. This increased risk of stroke was attributed to potentially inadequate deairing, fibrillating-heart techniques, prolonged cardiopulmonary bypass, cross-clamp times, and a retrograde perfusion strategy. Within our hospital this was not shown, which might be attributed to adherence to standard operative procedures and smooth passage of the learning curve. Overall, the majority of the papers reporting on comparative safety suggest that minimally invasive mitral valve surgery is at least as effective as the sternotomy approach across most perioperative complications. In addition to safety, decreased intensive care unit (ICU) stay, decreased hospital stay, decreased postoperative pain, improved patient satisfaction, faster return to normal physical activities, and improved overall quality of life have been demonstrated. For certain patient groups, such as those with obesity, reoperation, chronic obstructive pulmonary disease, and those including elderly patients, the minimally invasive procedure has been shown to be beneficial.