Ann Thorac Surg 2006;82:e27-e28
© 2006 The Society of Thoracic Surgeons
How to do it
Graft to Coronary Artery Shunt During Off-Pump Coronary Artery Bypass Grafting
Hiroshi Iida, MD, PhDa,*,
Hideaki Mori, MD, PhDb,
Yoshio Sudo, MD, PhDa,
Yasuyuki Yamada, MD, PhDb,
Kunihiro Eda, MD, PhDb,
Yuho Inoue, MD, PhDa,b
a Department of Cardiovascular Surgery, Kimitsu Central Hospital, Sakurai Kisarazu, Chiba
b Department of Cardiothoracic Surgery, Dokkyo University School of Medicine, Mibu, Tochigi, Japan
Accepted for publication June 1, 2006.
* Address correspondence to Dr Iida, Department of Cardiovascular Surgery, Narita Red-Cross Hospital, Iidachou Narita, Chiba 286523, Japan (Email: iidahomburg{at}hotmail.com).
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Abstract
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We have developed a simple technique for temporary shunt from the saphenous vein graft to the coronary artery during off-pump coronary anastomosis. The ends of a 2-mm diameter tube were inserted into the distal end of the saphenous vein graft in which proximal anastomosis had been established and into the right coronary artery crux. Blood flow sufficient to maintain adequate hemodynamics was obtained through the shunt tube while suturing around the tube. We successfully employed this technique in 5 patients with acute coronary syndrome. We suggest that this technique may represent an addition to the armamentarium for off-pump anastomosis to the right coronary artery.
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Introduction
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Although off-pump coronary artery bypass grafting (OPCAB) has grown in popularity [1–6], stabilization for anastomosis to the right coronary artery (RCA) sometimes represents deterioration of hemodynamics [1]. To address this problem, we have developed a temporary shunt from the saphenous vein graft (SVG) to the coronary artery for patients with stenosis of the proximal RCA.
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Technique
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Intravenous heparin (200 IU/kg) was given to obtain activated clotting time greater than 300 seconds, which is our standard OPCAB protocol, and off-pump anastomosis between the internal thoracic artery (ITA) and the left descending artery (LAD) were created using previously described methods [1, 2]. The proximal end of the SVG was secured to the ascending aorta either by running suture under a partial clamp or by using an anastomosis device. A 2-mm diameter vinyl chloride tube (Atom multipurpose tube; Atom Medical Corp, Tokyo, Japan) was cut to a length of 5 cm. Half of that length was inserted into the distal end of the SVG and snared with elastic tape. An adequate amount of sponge was placed behind the heart, and the anterior wall of right ventricle was suched and lifted with a vacuum cup access device (Xpose; Guidant Corp, Cupertino, CA). The 3 RCA (American Heart Association coronary artery numbering system, 1975) was next exposed, and subcoronary snare tapes were placed 1 cm proximal and distal to the intended target site. The other end of the tube was inserted toward the distal RCA through the arteriotomy made for the anastomosis. The SVG and RCA including the shunt tube were snared with elastic tapes and tourniquets. When the clamp on the SVG was opened and the RCA was occluded proximal to the arteriotomy, mean blood flow of 20–40 mL/min through the SVG and shunt tube was measured by ultrasound transit-time flowmeter (Transonic HT313; Transonic Systems Inc, Ithaca, NY). The running suture around the tube was performed with minimal bleeding and under stable hemodynamics (Fig 1). At the end of anastomosis, the tourniquets were released, and the tube was first drawn up into the SVG and then removed through the anastomosis site. The remaining few sutures were sewn to complete the anastomosis. The study was approved by the Institutional Review Board, and individual informed consent was obtained from each patient before surgery. We applied this technique in 5 elderly patients (75.0±6.0 year old) with acute coronary syndrome (ACS). Hemodyamics remained stable during OPCAB, and an average of 2.6 grafts were established per patient. Postoperative courses were uneventful, and postoperative angiography showed that grafts and coronary artery near the anastomosis did not manifest stenosis.
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Fig 1. Illustration showing a shunt tube inserted into the saphenous vein graft (SVG) and 3 right coronary artery (RCA) during off-pump anastomosis. (Acs. Ao. = ascending aorta.)
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Comment
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The OPCAB procedure is becoming more popular and has produced good short-term outcomes [3]. However, still fewer grafts tend to be performed in OPCAB procedure than with on-pump coronary artery bypass grafting (CABG) [1, 3–5]. The quality of the anastomosis to the braches of RCA and circumflex artery (CX) performed using the OPCAB technique might be jeopardized less accessibility [2, 4]. The procedures for 4 and CX require that the apex remain in an upright position, which directly affects hemodynamics especially for patients with impaired cardiac function [1]. Anastomosis to the RCA crux may cause ischemia in the entire inferior wall and catastrophic hemodynamic destabilization. The application of OPCAB to patients with ACS remains controversial [5, 6]. It is true that cardiopulmonary bypass is capable of maintaining stable systemic circulation in all patients and provides good exposure of the coronary arteries for precise and accurate anastomosis [1, 6]. However, several studies have reported that the inflammatory reactions incited by cardiopulmonary bypass, global myocardial ischemia secondary to cardioplegic arrest and systemic complications, such as embolism, induced by cardiopulmonary bypass may negate or supersede any potential benefits in these patients [2, 6]. The technique described in this report may provide an alternative to CABG for some ACS patients. It is particularly fit for use in establishing the anastomosis between SVG and the 3 RCA subsequent to the anastomosis of ITA to LAD, as the tube can be smoothly inserted into this part, and the distal right coronary artery needs relatively greater blood supply than do other areas. After the revascularization of LAD and RCA, the heart was able to be displaced to expose CX in 2 of the 5 patients.
Intracoronary shunt tubes are useful for anastomosis to LAD, distal RCA, and branches of the CX [1, 2]. However, during stabilization of stenotic proximal RCA, the intracoronary shunt tube is sometimes unable to provide adequate blood supply to the distal RCA due to its small efficient inner diameter and reduced driving pressure. Femoral artery to coronary shunt has been reported, but this procedure requires a long line, which is characterized by blood flow resistance. The vinyl chloride tube that we used in this procedure was short and wide enough to obtain adequate blood flow, which was not significantly disturbed by stabilization of the RCA. The costs for the material were lower. Intracoronary shunt tubes and snaring of the coronary artery are widely used, and have been shown to present a small risk of intimal damage and coronary spasm. Given this, we consider our shunt tube as safe from such complications.
As the wall of arterial grafts is rich in smooth muscle and there is scant experience in the use of shunt tubes and snare tape in this context, we feel there is some risk that the insertion of the shunt tube into arterial grafts may cause spasm. Additionally, bypass to RCA crux is not indicated in cases in which the distal RCA is stenotic. Avoiding aortic manipulation during OPCAB has been reported as reducing the incidence of embolic complications, but SVG was not abandoned for patients with unstable condition.
We conclude that the SVG to 3 RCA shunt during anastomosis may represent a simple new addition to the surgical strategies for OPCAB in the presence of proximal RCA stenosis, particularly in elderly patients and patients with ACS in unstable condition.
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References
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- Brown JM, Poston RS, Gammie JS, et al. Off-pump versus on-pump coronary bypass grafting in consecutive patientsdecision-making algorithm and outcomes. Ann Thorac Surg 2006;81:555-561.[Abstract/Free Full Text]
- Hassanein W, Albert AA, Arnrich B, et al. Intraoperative transit time flow measurementoff-pump versus on-pump coronary artery bypass. Ann Thorac Surg 2005;80:2155-2161.[Abstract/Free Full Text]
- Williams ML, Muhlbaier LH, Schroder JN, et al. Risk-adjusted short- and long-term outcomes for on-pump versus off-pump coronary artery bypass surgery Circulation 2005;112(Suppl I):366-370.
- Caputo M, Reeves BC, Rajkaruna C, Awair H, Angelini GD. Incomplete revascularization during OPCAB surgery is associated with reduced mid-term event-free survival Ann Thorac Surg 2005;80:2141-2147.[Abstract/Free Full Text]
- Sellke FW, DiMaio JM, Caplan LR, et al. Comparing on-pump and off-pump coronary artery bypass grafting Circulation 2005;111:2858-2864.[Abstract/Free Full Text]
- Kerendi F, Puskas JD, Craver JM, et al. Emergency coronary artery bypass grafting can be performed safely without cardiopulmonary bypass in selected patients Ann Thorac Surg 2005;79:801-806.[Abstract/Free Full Text]
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Abstract
Introduction
