Ann Thorac Surg 2004;78:352-354
© 2004 The Society of Thoracic Surgeons
How to do it
A simple technique of introducing intracoronary shunts for off-pump coronary artery bypass surgery
Hitoshi Yokoyama, MD, PhD*a,
Shinya Takase, MDa,
Yukitoki Misawa, MDa,
Koki Takahashi, MDa,
Yoichi Sato, MDa,
Hirono Satokawa, MDa
a Department of Cardiovascular Surgery, Fukushima Medical University, Fukushima, Japan
Accepted for publication May 14, 2003.
* Address reprint requests to Dr Yokoyama, Department of Cardiovascular Surgery, Fukushima Medical University, 1-Hikarigaoka, Fukushima 960-1295, Japan
e-mail: hitoshiy{at}fmu.ac.jp
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Abstract
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We describe a simple technique of introducing intracoronary shunts for off-pump coronary artery bypass. This technique, with an aid of micro-bulldog clamp, provides both a test clamp with ischemic preconditioning effect, and a quick and easy introduction of intracoronary shunt, giving a clear visualization of coronary anastomosis site and distal coronary artery perfusion. We recommend this technique as another effective modality in off-pump coronary artery bypass surgery.
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Introduction
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Off-pump coronary artery bypass (OPCAB) has been reported recently with satisfactory surgical outcome [1]. The intracoronary shunt has been developed as an effective technique for OPCAB to secure bloodless anastomosis site and distal coronary perfusion [2], although it has a potential risk of endothelial alteration. This technique has been demonstrated to prevent regional myocardial dysfunction and hemodynamic deteriorations during the coronary anastomosis in OPCAB [3].
The intracoronary shunt in OPCAB, however, is not preferred by all surgeons, mainly because of its technical difficulties. The positioning of this tiny material into the small coronary artery through a limited arteriotomy has been considered troublesome and time wasting [4]. Thus, recent efforts have been made to refine shunt insertion technique [5]. We describe a simple technique for quick introduction of the intracoronary shunt, which has been conducted in 150 consecutive cases with satisfactory results.
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Technique
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A stabilizer (Octopus III, Medtronic, Inc, Minneapolis, MN) is applied to stabilize the target coronary artery on the beating heart. Once the anastomosis site on the coronary artery is decided, bilateral fat tissue around the proximal coronary artery is bluntly dissected (Fig 1A),
being careful to avoid injuring cardiac veins. A cross-clamp is applied to the proximal coronary artery and surrounding tissue by a micro-bulldog clamp (Diethrich micro-bulldog clamp with 80 g of closing pressure, No. 20 to 0310, Geister Meditintechnik, Tuttlingen, Germany) for 3 minutes (Fig 1B), while we tailor the bypass graft and determine an appropriate size of the flexible silicone-constructed intracoronary shunt (Clearview intracoronary shunt, Medtronic, Inc.). During this test clamping, the anesthesiologist should pay close attention to changes in the patient's hemodynamics and electrocardiogram. The clamp is then released to reperfuse the coronary artery, providing an ischemic preconditioning effect [6]. A coronary arteriotomy is made with a microknife until blood leakage is seen (Fig 1C). Instantly, the micro-bulldog clamp is applied again to decrease the blood leakage for a visible extension of the coronary arteriotomy with scissors (Fig 1D). The long arm of the shunt is introduced into the proximal coronary artery while loosening the clamp (Fig 1E). Once the long arm passes the clamp site, the clamp is closed again to hold the long arm in the proximal coronary artery. The surgeon can observe the blood flow through the shunt even though the clamp is applied (Fig 1F). Then, the short arm is introduced into the distal coronary artery while the micro-bulldog clamp prevents an escape of the long arm (Fig 1G). Holding the short arm next to the bulb with a ring-tipped forceps blocks the intrashunt blood flow, allowing clear visualization of the distal coronary arteriotomy. Once both arms are placed in the coronary artery, the position of the shunt can be adjusted while the clamp is applied (Fig 1H). The clamp can be removed if the blood leakage from the arteriotomy is negligible.
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Fig 1. Introduction of intracoronary shunt with an aid of micro-bulldog clamp. Once the anastomosis site on the coronary artery is identified, bilateral fat tissue around the proximal coronary artery is bluntly dissected (A). For a test clamp, the micro-bulldog clamp is applied for 3 minutes (B). The clamp is released to reperfuse the coronary artery, providing an ischemic preconditioning effect. A coronary arteriotomy is made with a microknife (C). The micro-bulldog clamp is applied again to decrease the blood leakage for a visible extension of the coronary arteriotomy with scissors (D). The long arm of the shunt is introduced into the proximal coronary artery while loosening the clamp (E). The clamp is closed again to hold the long arm in the proximal coronary artery (F). The short arm is introduced into the distal coronary artery while the micro-bulldog clamp prevents an escape of the long arm (G). The position of the shunt can be adjusted while the clamp is applied (H).
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Comment
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The intraluminal shunt in OPCAB has two major advantages: distal coronary perfusion and clear visualization of the anastomosis. With intracoronary shunts in OPCAB, fewer ischemic events (eg, myocardial dysfunction, ventricular arrhythmia, postoperative myocardial stunning) are expected compared with simple local coronary occlusion[3, 4, 7]. The shunt also provides a clear visualization of the coronary arteriotomy to achieve more precise anastomosis. Both advantages offer a good chance of unhurried and meticulous anastomosis, particularly for training surgeons [8]. However, a major drawback of the intraluminal shunt is that agile and rapid shunt positioning is sometimes difficult and time consuming [4]. Previously, we often experienced slipping out of the preintroduced arm when trying to vend and introduce the other arm.
This novel technique has several advantages. First, this technique can provide an ischemic preconditioning effect with the small bulldog clamp. Recently, Luikka and associates demonstrated decreased myocardial enzyme release and better cardiac performance after OPCAB with ischemic preconditioning in a controlled, randomized, prospective study [6]. Second, the micro-bulldog clamp decreased the blood leakage from the coronary arteriotomy for well-visible and safe extension of the coronary arteriotomy. Importantly, the micro-bulldog clamp fixes the proximal end of the intraluminal shunt, easing the insertion of the other end. This clamp with a mild closing pressure allows intrashunt blood flow into the distal coronary artery. Therefore, the clamp can be left in place to decrease proximal blood leakage when the shunt size is too small. The clamp can also be placed during coronary anastomosis, preventing the shunt from slipping away. This technique is most useful for the left anterior descending artery (Fig 1), which is our first anastomosis site of choice in multivessel OPCAB. This technique is also applicable to the lateral and posterior wall of the coronary arteries, eg, obtuse marginal and posterior descending arteries, as long as the exposure of proximal coronary artery is satisfactory.
Several technical tips should be addressed when applying this new technique. The clamp site should be chosen between 5 and 10 mm from the proximal end of the coronary arteriotomy to allow enough room for the long (12 mm) arm of the shunt and for the placement of anastomosis sutures. Any occlusion technique, such as snares and clamps, carries a potential risk of endothelial injury [8]. An atheroma-free coronary artery without stenosis is desirable for the clamp site, avoiding the risk of plaque rupture or detachment even though the mild-pressure micro-clamp would be applied with the surrounding fat tissue or bilateral cardiac veins to minimize the risk of coronary artery injury. Although we recommend the flexible intracoronary shunt with soft beveled tips, the insertion of intraluminal shunts should be gentle to reduce the risk of acute coronary artery occlusion. In our consecutive 150 cases of OPCAB with this technique, we observed no intraoperative complications such as any injury or acute occlusion of the coronary artery, or the postoperative angiographic occlusion at the clamp site.
This simple and feasible technique provided unhurried, well-visible coronary anastomosis with distal coronary artery perfusion, preventing acute myocardial dysfunction and hemodynamic derangement. This novel technique is recommended as another tool during the OPCAB.
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Acknowledgments
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The assistance of Medtronic, Inc, in the preparation of the art is greatly acknowledged.
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References
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- Cleveland J.C., Shroyer L.W., Chen A.Y., Peterson E., Grover F.L. Off-pump coronary artery bypass grafting decreases risk-adjusted mortality and morbidity. Ann Thorac Surg 2001;72:1282-1289.[Abstract/Free Full Text]
- Rivetti L.A., Gandra S.M.A. Initial experience using an intraluminal shunt during revascularization of the beating heart. Ann Thorac Surg 1997;63:1742-1747.[Abstract/Free Full Text]
- Yeatman M., Caputo M., Narayan P., Ghosh A.K., Ascione R., Angelini G.D. Intracoronary shunts reduce transient intraoperative myocardial dysfunction during off-pump coronary operations. Ann Thorac Surg 2001;73:1411-1417.
- D'Ancona G., Donias H.W., Bergsland J., Karamanoukian H.L. Myocardial stunning after off-pump coronary artery bypass grafting: safeguards and pitfalls. Ann Thorac Surg 2001;72:2182-2183.[Free Full Text]
- Patel N.C., Pullan D.M., Fabri B.M. 'Shunt shuffle'—a simple technique of introducing intracoronary shunts for off-pump coronary artery bypass. Eur J Cardiothorac Surg 2002;21:1121-1122.[Abstract/Free Full Text]
- Lauikka J., Wu Z.K., Iisalo P., et al. Regional ischemic preconditioning enhances myocardial performance in off-pump coronary artery bypass grafting. Chest 2002;121:1183-1189.[Abstract/Free Full Text]
- Caputo M., Chamberlain M.H., Ozalp F., Underwood M.J., Ciulli F., Angelini G.D. Off-pump coronary operations can be safely taught to cardiothoracic trainees. Ann Thorac Surg 2001;71:1215-1219.[Abstract/Free Full Text]
- Hangler H.B., Pfaller K., Antretter H., Daput 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]
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Abstract
Introduction
