MMCTS
(February 19, 2007). doi:10.1510/mmcts.2005.001701
Copyright © 2007 European Association for Cardio-thoracic Surgery
Procedure
Use of radial artery for coronary revascularization
Brian F. Buxton*,
Siven Seevanayagam and
Rahul Kaiche
Austin Hospital, University of Melbourne, Melbourne, Victoria, Australia
* Corresponding author: * Department of Cardiac Surgery, Austin Hospital, Studley Road, Heidelberg 3084, Australia. Tel.: +61 3 9496 5453; fax: +61 3 9459 6220. E-mail: brian.buxton{at}austin.org.au
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Summary
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Techniques of harvesting, strategies and techniques of implantation are presented. The radial artery, along with the internal thoracic artery, has wide application in coronary artery bypass grafting. The radial artery is implanted as a standard aorto-coronary, Y graft or extension graft. The application is extended by the use of sequential techniques.
Key Words: Coronary artery bypass grafts • Ischemic heart disease • Radial artery
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Introduction
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History
The radial artery was introduced by Carpentier in 1971 as a coronary artery bypass conduit [1]. The early high occlusion rate led to a temporary avoidance of this technique. Acar, in 1989, found early grafts to be free of disease and this led to the revival of the radial artery as a coronary artery bypass graft [2]. These initial failures were attributed to poor selection, harvesting techniques causing endothelial damage and lack of understanding of the underlying physiology of the radial artery. Careful harvesting techniques, with preservation of the endothelium and vasodilatation of the thick muscular media, avoidance of ischemia and improvement of implantation techniques have resulted in improved graft patency.
Surgical anatomy
The brachial artery divides into the radial and ulnar arteries 1 cm below the level of the elbow joint. The radial artery runs in the proximal two thirds of anterior compartment of the forearm and continues under the cover of the brachioradialis muscle. In the distal one third it emerges to be covered only by skin, superficial fascia, and deep fascia. It lies in turn on the tendon of biceps, supinator, pronator teres, flexor digitorum superficialis, flexor pollicis longus, pronator quadratus and the lower end of the radius (Schematic 1). The radial artery terminates in a deep and superficial carpal arch (Schematics 2 and 3).
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Schematic 1 The major arteries and superficial muscles of the forearm. The radial artery lies between the brachioradialis and flexor carpi radialis muscles in the proximal forearm, and beneath the deep fascia in the distal forearm. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Schematic 2 Arteries of the forearm. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Schematic 3 Arteries of the hand showing superficial and deep palmar arches. [Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Anatomic variations may result in hand ischemia, if overlooked during harvest. A high origin occurs in approximately 14% of patients, and in 9% of patients, the superficial brachial artery is present. There are a number of variations in the anastomosis around the wrist and hand. In approximately 6% of patients the radial artery is the dominant supply to the hand. Allen testing, or one of its modifications is, therefore, essential prior to radial artery harvesting. The modified Allen test is reliable. However, harvesting the RA in the presence of a high bifurcation of the superficial palmar branch or poor communication between ulnar and radial contributions to the superficial and the deep carpal arches may lead to hand ischemia (Schematics 4 and 5).
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Schematic 4 Anatomic variation of the radial artery in the forearm and hand. Dominant radial artery. Note absence of the superficial palmar arch and small caliber of the ulnar artery. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Schematic 5 Anatomic variation of the radial artery in the forearm and hand. Proximal origin of the superficial palmar branch of the radial artery. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Harvest techniques
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The radial artery is harvested using an open technique. Hemostasis is achieved by the use of electrocautery and metal clips. The use of ultrasound (harmonic scalpel – MMCTSLink 69) may facilitate hemostasis and minimize trauma. More recently, the endoharvest technique has gained popularity, by minimizing the length of surgical incision. These operations can be performed through a small incision of about 5 cm in the line of the radial artery just above the wrist.
Open technique
The arm is externally rotated and abducted to 90°. The radial artery and its collateral branches are exposed after division of the deep fascia (Video 1).
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Video 1 Open technique of radial artery harvest: exposure and division of lower end.
The radial artery is exposed after division of the deep surgical fascia through an incision in the forearm. Avoidance of the wrist area improves patient comfort. The radial artery is harvested by division of arterial branches and collateral veins using sharp dissection and minimal diathermy. The artery is clipped distally and dilated.
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The distal end is divided approximately 3 cm above the level of the wrist joint, however, if a small segment is required, the distal end of the radial artery should be avoided, as this area is prone to calcification and atherosclerotic disease, compared with the upper end. After introduction of a vasodilator solution, the dissection is completed proximally, with the artery allowed to pulsate under arterial pressure (Video 2).
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Video 2 Mobilization and pharmacological dilatation of the radial artery.
The mobilization is completed and the radial artery marked with dye to identify orientation during implantation. A mixture of buffered papaverine and blood is introduced into the distal end. Papaverine: 1 mM or 400 mg/100 ml.
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The upper end of the radial artery is surrounded by the confluence of large veins from the forearm, which require mobilization and to identify the proximal end of the radial artery, thus, avoiding the bifurcation of the brachial and in the ulnar arteries (Video 3).
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Video 3 Division of the upper end of the radial artery.
Dissection of the upper end is completed to the level of the large muscular branch below the recurrent artery. Avoiding the bifurcation of the brachial artery protects the ulnar artery.
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Endoharvest
Endoharvest techniques are becoming increasingly popular. A special retractor exposes the radial artery after division of the deep fascia. Hemostasis is facilitated using the harmonic scalpel. A closed ligation technique for the proximal radial artery avoids a second incision. The minimal access approach provides a pleasing cosmetic result.
There appears to be little functional difference between the standard sharp dissection, electrocautery and endoharvest techniques (Video 4).
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Video 4 Endoharvest and the use of the harmonic scalpel. [permission granted by Ethicon Endo-Surgery, Inc.)
The radial artery is exposed through a small incision, approximately 3 cm proximal to the level of the wrist joint. The endoharvest retractor is introduced and the artery is then mobilized using the harmonic scalpel. The retraction is then removed and the radial artery is ligated between sutures. A loop is advanced around the radial artery to the level of transsection and then tied.
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Storage technique
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The radial artery is allowed to dilate under arterial pressure after a vasodilator solution has been introduced distally. It is then transsected and stored in the same solution. Alternatively, the radial artery may be left in-situ until required for implantation.
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Surgical strategy
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The radial artery is used as a standard aorto-coronary bypass. Many surgeons prefer the routine use of a radial artery Y or T graft with the left internal thoracic artery. Other variations include an end-to-end suture technique, particularly with the right internal thoracic artery to extend its application of the posterior descending or posterolateral branches.
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Grafting techniques
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Distal anastomoses
The number of vessels targeted by the radial artery may be extended through the use of one or more sequential anastomoses. These are performed in parallel when there is sufficient graft length, or as a diamond-shape when the radial artery and the target vessel lie at a right angle. Distal anastomoses can be performed using cardiopulmonary bypass or off-pump techniques.
Standard anastomoses
Surgeons have their own techniques of performing the distal anastomosis. Principles are similar. Adequate preparation of the distal end of the coronary artery bypass graft by the removal of surrounding fat, collateral veins and any adventitial bands avoids constriction in the graft at the site of the anastomosis. Selection of a disease-free segment of native coronary artery is desirable. Accurate intimal approximation minimizes the risk of platelet deposition and thrombus formation. A forehand technique has the advantage of simplicity (Video 5).
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Video 5 Preparation of the distal radial artery for anastomosis.
Prior to an anastomosis, 1–2 cm of the distal radial artery is isolated from its collateral veins. The artery is divided obliquely at 45° and enlarged to match the size of the opening in the native vessel.
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Commencing opposite the surgeon, anastomosis is completed at the end nearest the surgeon. Exposure for accurate placement of the apical sutures is facilitated by leaving the last 2 or 3 loops loose and using the adjacent sutures for retraction to insert the apical sutures (Video 6).
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Video 6 Anastomosis of the radial artery with the diagonal branch.
The anastomosis is commenced proximally using 7/0 polypropylene suture. After 2 or 3 sutures the radial artery is lowered onto the diagonal branch and the left side completed.
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Sequential anastomoses
Parallel: Sequential anastomoses using the radial arteries are popular (Schematic 6). A generous length of radial graft is required, particularly when a parallel grafting technique is employed. Sequential grafting provides efficient use of radial artery conduits. It is important to select the optimal sites on the target arteries. Alignment of the graft should not be compromised.
For sequential anastomoses, the incisions in the native coronary arteries and the grafts are performed in the longitudinal direction (Video 7). For in-parallel anastomoses, the length can be generous, similar to that for a distal anastomosis. Suturing is commenced away from the surgeon. The anastomosis is performed within the lumen (Schematic 6), or preferably, on the external aspect of the anastomosis. Suturing from the outside of the artery avoids inverting and exposing cut edges of the native coronary artery and the graft.
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Video 7 Completion of the radial artery to diagonal anastomosis.
The radial artery is retracted to the left and the second suture continues along the right side and is tied near the apex.
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Diamond: The diamond technique minimizes the length of conduit required. The anastomosis is modified by restricting the length the anastomosis to approximately twice the diameter of the native coronary artery, thus avoiding distortion (Schematics 7 and 8).
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Schematic 8 Sequential radial artery graft to the diagonal branch and distal left anterior descending coronary artery. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Proximal anastomoses
Proximal anastomoses are usually performed with the ascending thoracic aorta. Alternatively, the radial artery is used as a composite ‘Y’ graft with an internal thoracic artery or with another segment of the radial artery. An extension graft using the radial artery and in-situ right internal thoracic artery is a useful method of reaching posterolateral and post descending branches on the right side.
The standard proximal aortocoronary anastomosis is shown in Video 8. The proximal anastomosis with the aorta is performed at a site of convenience. Extensive calcification, atherosclerotic disease or inadequate graft length are limiting factors for aorto-radial artery anastomosis.
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Video 8 Standard proximal aortocoronary graft anastomosis.
After selection of an area in the aorta free from disease, the aorta is opened using a 3.5 mm punch. A standard end-to-side anastomosis is performed between the RA and the aorta using a continuous 6/0 polypropylene suture. The anastomosis is commenced on the side of the aortotomy opposite the surgeon.
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‘Y’-Graft [3]: The radial artery ‘Y’ graft is sutured to the left internal thoracic artery before cannulation or prior to off-pump coronary artery bypass. It is anastomosed at the level of the pericardial reflection (Schematic 9). A forehand technique commencing as high as possible in the left internal thoracic artery is preferable. Placement of the corner sutures in the ‘heel’ is facilitated by suturing from within the artery (Schematic 10). If the anastomosis is located inferiorly on the left internal thoracic artery, it is commenced distally (Schematic 11). The proximal radial artery fashioned obliquely for the ‘Y’ anastomosis. An additional suture may be required in the acute angle of the ‘Y’ to avoid excessive angulation at the site of the anastomosis.
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Schematic 9 Radial artery Y graft with the left internal thoracic artery. This is performed at the level of the pericardial window and a small incision is made on the thoracic wall side of the internal thoracic artery pedicle with a stab blade, and this is extended to a length of 3 to 4 mm. The radial artery is divided obliquely and anastomosed end-to-side with a continuous 7/0 polypropylene suture. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Schematic 10 Technique of Y graft anastomosis between the radial artery and the left internal thoracic artery. When the anastomosis is placed proximally, it is simpler to commence the anastomosis at the proximal end of the left internal thoracic artery incision. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Schematic 11 Alternative suture method. If the anastomosis is lower in the internal thoracic artery, it may be commenced at the heel. (Reprinted from Ischemic Heart Disease Surgical Management. Eds. Brian Buxton, O.H. Frazier, Stephen Westaby. 1999, with permission from Elsevier).
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Extension graft: A radial artery extension from the in-situ right internal thoracic artery is useful for grafting the posterior descending, posterolateral or even the distal circumflex branches (Photo 1, Schematic 12 and Video 9).
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Photo 1 Left internal thoracic artery with radial artery ‘Y’ graft. Surgeon's view, showing the internal thoracic artery aligned with the LAD and the radial artery passing laterally for anastomosis with the circumflex.
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Schematic 12 Extension graft. The radial artery is anastomosed to the distal in-situ right internal thoracic artery using an oblique end-to-end anastomosis.
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Video 9 Composite right internal thoracic artery/radial artery extension graft.
This shows the upper end of the right mediastinum. The pericardium is opened below the left brachiocephalic vein to expose the aorta, creating the tunnel behind the thymus for the in-situ right internal thoracic artery. Viewed from inside the pericardium, a Semb forceps is used to deliver the distal end of the right internal thoracic artery for preparation for the end-to-end anastomosis. The right internal thoracic artery and the radial artery are transsected at 45° to fashion an oblique anastomosis.
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After completion of the end-to-end anastomosis, the radial artery extension graft is seen lying on the right ventricle (Photo 2).
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Photo 2 A composite graft of right internal thoracic end-to-end anastomosis with the radial artery. This is shown lying in the course of the right coronary artery, the radial artery extension is seen passing posteriorly for anastomosis with the posterior descending and posterolateral branches of the right coronary artery.
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Innovations
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Complete arterial grafting using internal thoracic and radial artery grafts is readily achieved using off-pump coronary artery techniques. The coronary artery is isolated by one of the commercial stabilizers (Photo 3).
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Photo 3 Anesthetist's view of the Medtronic Octopus stabilizing device, placed alongside the left anterior descending coronary artery. [permission granted by Medtronic, Inc.].
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The jaws of the Octopus stabilizer – MMCTSLink 110 – retract the tissue away from the left anterior descending artery, providing excellent exposure (Photo 4).
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Photo 4 Surgeon's view of the stabilized left internal thoracic artery with soft occluding clamps, resulting in a blood-free field. Note the excellent exposure of the left anterior descending coronary artery with a 6 mm arteriotomy. [permission granted by Medtronic, Inc.].
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Results
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In a recent review of 379 papers, which compared the radial artery with the saphenous vein, the authors considered that 12 had provided the best clinical evidence. Ten were observational and 2 randomized studies. The authors concluded that there is evidence that the radial artery has a higher patency than saphenous vein grafts and they concluded that surgeons could confidently use the radial artery as a second coronary artery bypass graft in patients with severe native vessel stenosis [4].
A recent editorial indicated that while the radial artery had excellent handling characteristics, many of the issues remain unresolved. In particular, the pre-operative harvesting techniques, prevention and vaso-spasm, grafting strategies and long-term patency. Table 1 summarizes the recently published data cited in Ref. [5].
A randomized study of radial artery and saphenous vein revealed that at 4 years there was no difference in patency: the RA 88% versus saphenous vein 86%. The event-free survival of the radial artery was 86% compared with 89% for the saphenous vein [12].
Observational studies suggest that the radial artery is more durable than the saphenous vein. However, the preliminary results from controlled trials suggest that further follow-up is necessary to determine whether there are late benefits of the radial artery compared with saphenous vein.
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Acknowledgements
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Philip Hayward, Ethicon Endo-Surgery, Inc., Medtronic, Inc, Alistair Royse, Joe Harrison, Mardi Malone. Artwork supplied by Beth Croce.
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References
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- Carpentier A, Guermonprez JL, Deloche A, Frechette C, DuBost C. The aorta-to-coronary radial artery bypass graft. A technique avoiding pathological changes in grafts. Ann Thorac Surg 1973;16:111–121.[Medline]
- Acar C, Jebara V, Portoghese M, Beyssen B, Pagny JY, Grare P, Chachques JC, Fabiani JN, Deloche A, Guermonprez JL. Revival of the radial artery for coronary artery bypass grafting. Ann Thorac Surg 1992;54:652–659.[Abstract]
- Royse A. Complete arterial coronary artery bypass grafting using a left internal thoracic artery and a single radial artery Y graft. In: Buxton B, Frazier OH, Westaby S, editors. Ischemic heart disease surgical management. Mosby Interna- Fig 16.16:219.
- Georghiou GP, Vidne BA, Dunning J. Does the radial artery provide better long-term patency than the saphenous vein? Interact CardioVasc Thorac Surg 2005;4:304–310.[Abstract/Free Full Text]
- Mussa S, Choudhary BP, Taggart DP. Radial artery conduits for coronary artery bypass grafting: current perspective. J Thorac Cardiovasc Surg 2005;129:250–253.[Free Full Text]
- Acar C, Ramsheyi A, Pagny JY, Jebara V, Barrier P, Fabiani JN, Deloche A, Guermonprez JL, Carpentier A. The radial artery for coronary artery bypass grafting: clinical and angiographic results at five years. J Thorac Cardiovasc Surg 1998;116:981–989.[Abstract/Free Full Text]
- Possati G, Gaudino M, Alessandrini F, Luciani N, Glieca F, Trani C, Cellini C, Canosa C, Di Sciascio G. Midterm clinical and angiographic results of radial artery grafts used for myocardial revascularization. J Thorac Cardiovasc Surg 1998;116:1015–1021.[Abstract/Free Full Text]
- Iaco AL, Teodori G, Di Giammarco G, Mauro M, Storto L, Mazzei V, Vitolla G, Mostafa B, Calafiore AM. Radial artery for myocardial revascularization: long-term clinical and angiographic results. Ann Thorac Surg 2001;72:464–468; discussion 468–469.[Abstract/Free Full Text]
- Tatoulis J, Royse AG, Buxton BF, Fuller JA, Skillington PD, Goldblatt JC, Brown RP, Rowland MA. The radial artery in coronary surgery: a 5-year experience—clinical and angiographic results. Ann Thorac Surg 2002;73:143–148.[Abstract/Free Full Text]
- Possati G, Gaudino M, Prati F, Alessandrini F, Trani C, Glieca F, Mazzari MA, Luciani N, Schiavoni G. Long-term results of the radial artery used for myocardial revascularization. Circulation 2003;108:1350–1354.
- Khot UN, Friedman DT, Pettersson G, Smedira NG, Li J, Ellis SG. Radial artery bypass grafts have an increased occurrence of angiographically severe stenosis and occlusion compared with left internal mammary arteries and saphenous vein grafts. Circulation 2004;109:2086–2091.
- Buxton BF, Raman JS, Ruengsakulrach P, Gordon I, Rosalion A, Bellomo R, Horrigan M, Hare D. Radial artery patency and clinical outcomes – 5-year interim results of a randomized trial. J Thorac Cardiovasc Surg 2003;125:1363–1370.[Abstract/Free Full Text]
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Summary
Introduction
