Ann Thorac Surg 2004;78:722-724
© 2004 The Society of Thoracic Surgeons
How to do it
Interrupted distal anastomosis: the interrupted "porcupine" technique
Baron L. Hamman, MDa*,
Cory H. White, BSa
a Baylor University Medical Center, Clinical Cardiology Research Center, Dallas, Texas, USA
Accepted for publication November 20, 2003.
* Address reprint requests to Dr Hamman, 3600 Gaston Ave, Barnett Tower 1202, Dallas, TX 75246, USA
e-mail: bhamman{at}heartplace.com
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Abstract
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The distal coronary artery bypass graft anastomosis created by an interrupted technique using nitinol clips is likely superior to that created with continuous suture because surgeons place clips with optimal visualization, and the anastomosis exhibits optimal compliance and cannot become a "purse-string" once constructed. Skillful use of the clips allows the surgeon to work in the ever more cramped quarters of the minithoracotomy or minimally invasive incision. Anastomosing vessels without knot tying is a valuable practice in the application of remote and robotic surgeries.
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Introduction
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The interrupted method of anastomosis construction is thought by many to be superior to the continuous method [1–4]. A benchmark study showed optimal left anterior thoracic artery to the left anterior descending artery (LAD) patency using anastomoses that were created using an interrupted technique [5].
The development and commercial distribution of reliable, small metal clips has allowed surgeons to construct arterial and venous anastomoses increasingly more quickly and accurately without a troop of orchestrated assistants [6]. This paper describes a technique that our nurses have dubbed the "porcupine technique," which may be applied to all conduit anastomoses, including tector grafts. The U-CLIP anastomotic device used was developed by Coalescent Surgical (Sunnyvale, CA).
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Technique
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The assistant opens the incised portion of the graft to allow the first U-CLIP to be placed to the immediate right of the heel. The surgeon passes the needle inwardly, engaging the coil portion of the clip into the conduit (Fig 1).
The second clip is placed into the conduit to the right of the first. The surgeon holds delicate downward tension with the first U-CLIP while an assistant holds countertraction on the vein or artery, thus triangulating the conduit for stability (Fig 2).
The native coronary artery is approached while still holding the second U-CLIP needle in the needle driver (Fig 3). This second U-CLIP needle is then passed from the inside to the outside of the native coronary artery. The clip is engaged but not deployed, thus allowing manipulation of the tissue as the anastomosis is constructed.
The first U-CLIP that was placed just to the right of the heel is then placed and engaged in the native coronary artery (Fig 4) while holding gentle traction on the second U-CLIP. The symmetry and straight alignment of the clips before deployment are crucial for the integrity and fluidity of the anastomosis.
The remaining U-CLIPs are placed in a clockwise fashion on the native coronary artery until the toe is engaged. Placing and engaging each U-CLIP without deploying the shape-changing members allows the two edges of the conduit and the native coronary artery to gape open during construction, thus allowing perfect visibility for placing the remaining clips (Fig 5).
Working symmetrically, with even spacing along the anastomosis, each clip is left open, with the flexible members protruding up from the epicardium resembling the back of a porcupine. That minimizes the tension on the tissue with each consecutive clip placement. With successful placement of all U-CLIPs, the clip portions are engaged but not deployed; they are inspected for spacing and symmetrical orientation, and then deployed by crushing the fibers in the flexible members. A light pinch-and-release with the needle driver on the black fibrous members is used to deploy the devices, thus changing them from a U shape to an "omega" shape. Fewer clips are better, and we believe that the goal should be 8 to 12 clips for an end-to-side anastomosis; 8 to 10 clips are optimal for a side-to-side anastomosis. The flexible members are grouped for common collection at the completion of the anastomosis even in beating-heart cases (Fig 6).
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Comment
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The authors have now created more than 200 additional anastomoses over a 6-month period. Patients in this study have been followed up for 6 to 12 months postoperatively. No patient in this study has demonstrated early anastomotic stenosis from technical errors or problems thereof.
The use of the interrupted technique is beneficial because the potential for the purse-string effect is avoided, and compliance of the completed anastomosis is optimized. The length of time to create each anastomosis is similar to that needed for the continuous technique, and ranged from 5 to 12 minutes per distal anastomosis. Although most surgeons administer clopridigil in cases of off-pump coronary artery bypass graft surgery, when the clips are used during on-pump surgery, we do not employ other special anticoagulation therapy. The clips are small and are not readily visible on a chest roentgenogram, but can be seen on a computed tomography scan.
Both the U-CLIPs and the suturing anastomoses have finite learning curves. Mastering sutured anastomoses serves only as a primer to mastering the interrupted U-CLIP anastomosis. We estimate that about 20 anastomoses are optimal (all in a teaching model) to master the initial rigidity of the U-shaped nondeployed clips and to feel the deployment to their final "omega" shape. That some surgeons have experienced difficulty in removing a deployed clip only amplifies the usefulness of this "porcupine" technique, which allows the surgeon to carefully inspect the anastomosis before final deployment.
At an average cost of $10 per anastomosis, some may quarrel with the cost of a better anastomosis, but we think reported long-term outcomes will speak for themselves [5].
The 30 reported cases demonstrate excellent use of the U-CLIPs to create complex branching arterial anastomoses. There were 27 Y-type or Tector-type anastomoses, 15 side-to-side anastomoses, and 70 end-to-side arterial anastomoses in 30 patients. In contradistinction, there was 1 Y-type anastomosis, 6 side-to-side anastomoses, and 20 end-to-side venous anastomoses in these same patients. Suture was used in only 3 anastomoses and was determined by the fragility of the distal target.
Three patients had persistent angina, although all had a reduction in angina class. Five patients had recatheterization, and 3 had noninvasive stress tests, none of which showed any evidence for ischemia; follow-up indicated possible need for reintervention.
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References
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- Wold R.K., Alderman E.L., Caskey M.P., et al. Clinical and six month angiographic evaluation of coronary arterial graft interrupted anastomoses by use of a self-closing clip device: a multicenter prospective clinical trial. J Thorac Cardiovasc Surg 2003;126:168-178.[Abstract/Free Full Text]
- Loop F.D. Technique for performance of internal mammary artery–coronary artery anastomosis. J Thorac Cardiovasc Surg 1979;79:460-463.
- Berger P.B., Alderman E.L., Nadel N., Schaff H.V. Frequency of early occlusion and stenosis in a left internal mammary artery after surgery through a median sternotomy on conventional bypass. Circulation 1999;100:2353-2358.[Abstract/Free Full Text]
- Ballyk P.D., Walsh C., Butany J., Ojha M. Compliance mismatch may promote graft-artery intimal hyperplasia by altering suture-line stresses. J Biomech 1998;31:229-237.[Medline]
- Loop F.D., Lytle B.W., Cosgrove D.M., et al. Influence on the internal mammary artery graft on 10-year survival and other cardiac events. N Engl J Med 1986;314:1-6.[Abstract]
- Hill A.C., Maroney Y.P., Virmani R. Facilitated coronary anastomosis using a nitinol U-Clip device: bovine model. J Cardiovasc Surg 2001;121:859-869.
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Abstract
Introduction
