Ann Thorac Surg 1998;65:1597-1598
© 1998 The Society of Thoracic Surgeons
Original articles: cardiovascular
Invited commentary
Robert A. Dion, MDa
a Department of Cardiovascular Surgery, Cliniques Universitaires Saint-Luc, Ave Hippocrate 10, B-1200 Bruxelles, Belgium
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Invited commentary
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In this interesting article, Meseguer and associates present their experience with 7 cases of left main coronary artery (LMCA) patch angioplasty. The LMCA was approached posteriorly in 1 patient and anteriorly in the remaining 6 patients. My colleagues and I also definitely banned the posterior approach because of the less than optimal exposure of the distal part of LMCA. Also, because of the anatomic configuration, the posterior aspect of the LMCA absorbs most of the head of systolic pressure, which might explain why the ulcerated plaques always are localized there; therefore, incising the posterior wall is more hazardous than incising the anterior wall, which is protected from the head of pressure by the acute angle that it makes with the aortic wall.
In their last 5 cases, an autologous pericardial patch was used, and 2 patients needed an early reoperation. Both patients did not have a strictly ostial LMCA stenosis. Interestingly, in our experience, we also had 2 cases of early failure when a pericardial patch was used to enlarge an LMCA stenosis that was not strictly ostial. We fear for the lack of fibrinolytic activity of the pericardium compared with that of the saphenous vein and, at the present time, restrict its use to pure ostial repair.
Although LMCA stenoses can be generated by inflammatory diseases, radiation therapy, or fibromuscular dysplasia, atherosclerosis is now regarded as the most common cause, and this is supported by the preoperative prevalence of risk factors for atherosclerosis. In our experience, even in the presence of atheromatous disease, LMCA surgical angioplasty was safe and reproducible provided that there was no involvement of the distal bifurcation and no heavy calcifications on the preoperative angiogram. The excellent exposure offered by the anterior approach allows for a thorough inspection of LMCA before incizing its ostium. Like Meseguer and associates we often face unexpected calcified atheroma (57%) intraoperatively.
Conventional bypass grafting invariably leads to the definitive occlusion of LMCA, restores only retrograde perfusion to a rather extensive myocardial area, may result in competitive flow especially if the left anterior descending and circumflex arteries are both grafted, and consumes bypass material. Direct surgical angioplasty avoids these inconveniences and would allow percutaneous transluminal coronary angioplasty of distal coronary stenoses developing at the latest stages. Therefore, we certainly would have tried a percutaneous transluminal coronary angioplasty procedure in their patient 6 and even more so in patient 7.
A postoperative noninvasive restudy is certainly welcome to follow up these patients for it would favor a more systematic restudy of the LMCA patency. In cases where spiral computed tomographic imaging seems to have failed, spin-echo and gradient-echo magnetic resonance techniques have been used very efficiently by Briffa and colleagues [1]. Also, as Meseguer and associates state, electron-beam computed tomography is likely to offer in the near future an optimal definition of the coronary tree, including the LMCA.
Meseguer and associates have to be commended for their excellent surgical technique and clinical results, and for their attempt to design a noninvasive procedure to restudy the patients. They have contributed to establish LMCA surgical angioplasty as a safe and reproducible procedure that restores a more physiologic perfusion of the left coronary tree and is likely to better preserve the outcome of the patients, provided that well defined contraindications are respected: no involvement of the distal bifurcation and no heavy calcifications on the preoperative angiogram.
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References
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- Briffa N.P., Clarke S., Kugan G., Coulden R., Wallwork J., Nashef S.A.M. Surgical angioplasty of the left main coronary artery: follow-up with magnetic resonance imaging. Ann Thorac Surg 1996;62:550-552.[Abstract/Free Full Text]
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Invited commentary
References