Minimally invasive thoracoscopically assisted coronary artery bypass surgery

Minimally invasive techniques have been widely used in other surgical fields including video-assisted thoracic surgery (VATS) in thoracic surgery. These concepts are now being applied to cardiac surgery. The opportunities to make cardiac surgery less invasive include elimination of the median sternotomy incision, elimination of cardiopulmonary bypass and no manipulation of the aorta.

From January 1992 through September 1996, various aspects of minimally invasive cardiac surgery have been examined in the inanimate endoscopic trainer, animal model, human cadaver and in human clinical studies. Techniques of endoscopic sutured anastomosis as well as alternatives to suturing were first perfected in the inanimate trainer. Twenty animals then underwent endoscopic coronary artery bypass using the left internal mammary artery to the left anterior descending with circulatory support from an axial flow pump. Fifty eight minimally invasive coronary artery bypass procedures have been performed in humans using thoracoscopic assistance for internal mammary artery harvest.

One hundred fifty endoscopic coronary anastomoses were performed in the inanimate trainer with the endoscopic suturing technique being the preferred method. Time required to perform an anastomosis decreased from greater than 60 min to a mean of 20 min as technique and instruments were developed. In animals, methods of access as well as enabling surgical instruments to allow crossclamp of the aorta and performance of the anastomosis were developed. Fifty-eight humans underwent coronary artery bypass using the left internal mammary artery placed to the left anterior descending under direct vision through a limited anterior thoracotomy on a beating heart. The procedure was successful in 52 patients with conversions required in six patients. Techniques were developed for immobilization for performance of the anastomosis.

The ability to perform an endoscopic anastomosis still remains the rate limiting step for totally endoscopic coronary artery bypass surgery. The present MIDCAB (minimally invasive direct coronary artery bypass grafting) procedure is a significant advance in cardiac surgery, but still has limitations that make performance of an exact anastomosis still somewhat difficult and applicable only to single-vessel disease. Present efforts are directed toward extending the MIDCAB procedure by various immobilization and circulatory support devices and combining the MIDCAB procedure with catheter techniques for treating more advanced disease.