Parasternal Approach for Minimally Invasive Aortic Valve Surgery

Abstract

Aortic valve replacement for the stenotic or regurgitant aortic valve has been one of the major advances of medical science in the 20th century. Patients who have severe pressure gradients between the left ventricle and the aorta, or who have severely dilated hearts due to massive aortic regurgitation, are treated by insertion of a reliable mechanical or bioprosthetic device to relieve these hemodynamic abnormalities. This technique has saved hundreds of thousands of lives since the first successful aortic valve replacements by Harken et al,' and Starr et a12 in 1960. Since 1960, valve devices, incisions, and surgical techniques have evolved to the extent that, by the early 1990s, the risk of aortic valve replacement in patients without coronary disease was under 3% in most large centers in the world that do aortic valve replacement .3 The complete median sternotomy became the standard incision for aortic valve replacement in the late 1960s. This incision is flexible and relatively painless because it is a midline incision. It allows maximal exposure of all parts of the cardiac structure, and most importantly, enables physicians to effectively remove air from intracardiac structures. As interest in minimizing surgical trauma has increased, minimally invasive incisions for cardiac surgery are receiving increasing attention. The evolution of minimally invasive surgery in all surgical specialties began with Fogarty's conversion of the vastly complicated aortoiliac embolectomy to a balloon catheter technique via the groin vessels in the early 1960s. In orthopaedics, endoscopy for joint operations replaced open operations about 15 years ago. Approximately 10 to 15 years ago in general surgery, laparoscopic colocystectomy became the treatment of choice, replacing the open colocystectomy. In the last 5 years, the use of video-assisted thoracic surgery has been enormously important in redefining general thoracic surgical procedures to a much less invasive type of surgery for many pulmonary lesions. Minimally invasive cardiac surgery began with the use of techniques for the so-called direct-access coronary bypass, off cardiopulmonary bypass, performed through small incisions, primarily using the left anterior descending coronary artery and applied directly to it. At the same time, Port-Access systems, popularized by Heartport, Inc, Redwood City, CA,5 were developed to afford a minimally invasive incision for a coronary artery bypass graft that had the advantages of cardiopulmonary bypass, aortic cross-clamping by endoclamp, and cardioplegia for myocardial protection. Finally, the use of minimally invasive direct access incisions for cardiac valve surgery were developed in the early part of 1996, when investigators believed that small incisions, accessing only those chambers or vessels where the valve surgery would take place and aided by femoro-femoral bypass, would be an advantage for patients undergoing cardiac valve surgery without combined coronary These approaches have been extended widely, and include a Port-Access system9 for mitral but not aortic valve replacement.