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Ann Thorac Surg 2002;73:344-345
© 2002 The Society of Thoracic Surgeons

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Correspondence

Risk of coronary artery occlusion with snares during OPCAB

^a Department of Surgery and Research Center, Montreal Heart Institute, 5000 Belanger St East, Montreal, PQ H1T 1C8, Canada

e-mail: lpperrau{at}icm.umontreal.ca

To the Editor

We read with interest the article by Chen and colleagues about a new method of coronary occlusion during off-pump coronary artery bypass surgery (OPCAB) [1]. Indeed, the optimal and safest technique to obtain a bloodless field at the coronary anastomotic site, mandatory for the surgeon’s optimal visualization, remains to be discovered. Various systems have been developed such as direct clamping, intracoronary shunting, gas jet insufflation, and snaring sutures. Different types of coronary snares with various threads wrapped around the artery, with or without tourniquet, were developed to be minimally traumatic to the arterial wall and these remain the most widely used occlusive devices during OPCAB procedures. Some surgeons further protect the coronary artery from potential tourniquet injury by interposing a pledget.

A functional study in swine by Perrault and colleagues showed that snaring (with thread 4-0 Gore-Tex) to achieve hemostasis at the anastomotic site does not cause any endothelial dysfunction in healthy coronary arteries [2]. However, Hangler and associates [3] described coronary artery lesions secondary to snare application in patients before removal of the recipient heart before transplantation. Examination with scanning electron microscopy showed that snares cause focal endothelial denudation, microthrombosis, and atherosclerotic plaque rupture [3]. In addition, we have observed development of early multifocal stenosis on sites of coronary extravascular snaring 6 weeks after coronary bypass surgery in a diabetic patient who had extensive medial calcification [4]. Snares appear to be safe on relatively normal coronary arteries but can create severe acute or chronic lesions on atheromatous and calcified arteries.

The usual mechanism of coronary occlusion by snares involves application of a radial constraint with some harmonious dissipation of force uniformly around the artery, which is protected by surrounding tissue and some type of buttress. The mechanism of coronary occlusion proposed in this article differs substantially from the usual snares since hemostasis is obtained by means of kinking the artery between not only one but two pledgets. The mechanical force imposed on the arterial wall is a longitudinal plicature with stretching of the arterial wall on opposite sides of the plication. The isolated effect of this occlusive device on endothelial function remains to be determined but the endothelium is not likely be severely injured because it remains an extravascular hemostatic device without direct contact with the endothelial layer [2]. However, in our opinion, this mechanism of coronary occlusion could be more deleterious in arteries with atheromatous plaques that have an increased risk of rupture, dissection, and thrombosis. In addition, intracoronary shunts have their own inherent risk of trauma probably enhanced by the plication.

Hemostatic systems will probably remain necessary in OPCAB when direct suturing is involved, but the perfect system in terms of efficacy and safety remains to be developed. Because of the risks described above, use of hemostatic devices, especially on atheromatous and calcified arteries, must always be guided by the concern of producing as little trauma as possible. Trauma may be avoided by gentle surgical manipulation and knowledge of the potential complications associated with the different occlusive devices.

References

1. Chen Y.S., Chou T.F., Lee J.Y., Lin F.Y., Wang S.S. New method of coronary artery occlusion for beating-heart coronary artery bypass surgery. Ann Thorac Surg 2001;71:1712-1713.[Abstract/Free Full Text]
2. Perrault L.P., Menasché P., Bidouard J.P., et al. Snaring of the target vessels in less invasive bypass operations does not cause endothelial dysfunction. Ann Thorac Surg 1997;63:751-755.[Abstract/Free Full Text]
3. Hangler H.B., Pfaller K., Antretter H., Dapunt O.E., Bonatti J.O. Coronary endothelial injury after local occlusion on the human beating heart. Ann Thorac Surg 2001;71:122-127.[Abstract/Free Full Text]
4. Demaria R.G., Fortier S., Carrier M., Perrault L.P. Early multifocal stenosis after coronary artery snaring during off-pump coronary artery bypass in a patient with diabetes. J Thorac Cardiovasc Surg 2001;122:1044-1045.[Free Full Text]

This article has been cited by other articles:

				E. A Black, S. Ghosh, K. Sin, T. Spyt, and R. Pillai Off-Pump Coronary Artery Bypass Surgery Asian Cardiovasc Thorac Ann, December 1, 2004; 12(4): 379 - 386. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Roland G. Demaria Louis P. Perrault Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Demaria, R. G. Articles by Perrault, L. P. Search for Related Content PubMed Articles by Demaria, R. G. Articles by Perrault, L. P. Related Collections Minimally invasive surgery