Ann Thorac Surg 1998;66:985-987
© 1998 The Society of Thoracic Surgeons
Correspondence
How high should mammary artery be harvested for the minimally invasive approach?
Toshiya Ohtsuka, MDa
a Department of Cardiothoracic Surgery, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113, Japan
To the Editor
Luise and colleagues [1] have stated that complete harvest of the left internal mammary artery (LIMA) is not necessarily required for minimally invasive coronary artery bypass grafting. I agree that persistent branches from the LIMA have the least influence upon diastolic flow through the main trunk to the coronary artery.
The LIMA should be taken down as high as possible to avoid interference caused by pulmonary motion. It has quite often been observed that the medial edge of the left upper pulmonary lobe moves beyond the LIMA graft after anastomosis (Fig 1). In a review of preoperative computed tomographic scans of 28 patients undergoing minimally invasive coronary artery bypass grafting with the LIMA, it was found in all cases that the lung tissue lay between the LIMA and the upper mediastinum (Fig 2). Incompletely harvested LIMA grafts are pushed medially by the lung, and may have a steep curve around the pulmonary edge. Kinking or avulsion of the graft may be caused by coughing, and the results can be serious or even fatal [2].
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Fig 1. Intraoperative photograph via small thoracotomy taken just before wound closure, showing pulmonary edge (arrows) is moving medially beyond the left internal mammary artery graft (arrowhead).
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Fig 2. Preoperative ultrafast computed tomogram showing pulmonary tissue lies between the left internal mammary artery (arrowhead) and the upper mediastinum.
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In minimally invasive coronary artery bypass grafting, I have routinely been dissecting the LIMA as far as the upper margin of the first rib or higher with thoracoscopy [3]. The pedicles lay on the upper mediastinum and heart along the entire pathway to the coronary anastomosis without tension, and suffered no interference caused by pulmonary motion.
References
- Luise R., Teodori G., Di Giammarco G., et al. Persistence of mammary artery branches and blood supply to the left anterior descending artery. Ann Thorac Surg 1997;63:1759-1764.[Abstract/Free Full Text]
- McMahon J., Bergsland J., Arani D.T., Salerno T.A. Avulsion of the left internal mammary artery after minimally invasive coronary bypass. Ann Thorac Surg 1997;63:843-845.[Abstract/Free Full Text]
- Ohtsuka T., Wolf R.K., Hiratzka L.F., Wurnig P., Flege J.B. Thoracoscopic internal mammary artery harvest for MICABG using the Harmonic Scalpel. Ann Thorac Surg 1997;63:S107-S109.
