Ann Thorac Surg 2002;74:S1363-S1367
© 2002 The Society of Thoracic Surgeons
Supplement: Cardiothoracic Techniques and Technologies
Two generations of the St. Jude Medical ATG coronary connector systems for coronary artery anastomoses in coronary artery bypass grafting
Friedrich S. Eckstein, MDa*,
Luis F. Bonilla, MDd,
Hartzell Schaff, MDc,
Lars Englberger, MDa,
Stephan Windecker, MDb,
Paul Hindrichsd,
Thierry P. Carrel, MD
a Clinic for Cardiovascular Surgery, University Hospital, Bern, Switzerland
b Department of Cardiology, University Hospital, Bern, Switzerland
c Department of Surgery, Mayo Clinic, Rochester, Minnesota, USA
d St. Jude Medical Anastomotic Technology Group (ATG), Minneapolis, Minnesota, USA
* Address reprint requests to Dr Eckstein, MD, Clinic for Cardiovascular Surgery, University Hospital Berne, Freiburgstrasse, CH-3010 Berne, Switzerland.
e-mail: friedrich.eckstein{at}insel.ch
Presented at the Eighth Annual Cardiothoracic Techniques and Technologies Meeting 2002, Miami Beach, FL, Jan 23–26, 2002.
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Abstract
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BACKGROUND: In the past, coronary anastomoses have been performed using running and, occasionally, interrupted non-resorbable sutures. Recently, special interest has developed in mechanical anastomotic devices to facilitate minimal invasive techniques or limited access surgery. The experience with two series of patients undergoing coronary artery bypass grafting (CABG) using the St. Jude Medical ATG coronary connector systems (investigational stainless steel device, not yet commercially available) for vein-to–coronary artery anastomoses is reported here.
METHODS: Between November 2000 and April 2002, we evaluated two generations of distal coronary connector systems in 19 patients who were scheduled for multivessel CABG. One vein graft–to–coronary artery anastomosis per patient was performed with a stainless steel mechanical connector, in an ongoing investigational study. Although these two generations of the St. Jude Medical ATG coronary connectors have the same underlying construction, somewhat cumbersome loading of the first-generation system led to simplification of the second-generation system, which is currently evaluated.
RESULTS: With the first generation of distal connector, hemostasis was instantaneous in all cases, and all anastomoses were patent at the end of the procedure. However, retrograde flow to the native coronary artery was restricted in 1 patient. The connector was removed, and the anastomosis was performed with a running suture at the same site. Three-month angiography or magnetic resonance imaging angiography was available in 11 patients with 10 patent connector grafts. With the second-generation connectors one of five had to be removed because of leakage, and the anastomosis could be sutured at the same site. The other four connector anastomoses were patent and hemostatic at the end of the procedure.
CONCLUSIONS: The St. Jude Medical ATG coronary connector system is an effective device for sutureless vein graft to coronary artery anastomoses in CABG. The second-generation system presents a further development eliminating some drawbacks of the first generation such as cumbersome, time-consuming loading as well as suitability for smaller coronary arteries. These connectors allow construction of geometrically round anastomoses and theoretically may also be suitable for sequential anastomoses. After tremendous research and development efforts, an optimized mechanical connection system for small vessel anastomoses has been introduced into clinical investigation. This represents a major step in the era of sutureless vascular connections in cardiac surgery.
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Introduction
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| Drs Bonilla and Hindrichs disclose that they have a financial relationship with St. Jude Medical ATG.
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In coronary artery bypass grafting (CABG), the anastomoses are currently performed using running and, occasionally, interrupted nonresorbable sutures. Suturing has been developed as an effective method to attach vessels together since first reported by Carrel in 1904 [1]. However, the quality of the anastomosis is dependent on human capability, and each anastomosis will differ from the other depending on skill level, experience, exposure, and visualization, as well as on time permitted. Recently, the Anastomotic Technology Group (ATG) from St. Jude Medical (Minneapolis, MN) has developed a family of mechanical connectors facilitating connections between a vein graft and the ascending aorta (proximal connector) [2, 3] or between vein graft and the coronary artery (distal connector) [4, 5]. The vein graft–to–coronary artery connector is made of stainless steel; it is still an investigational device that is not commercially available. The connector creates a round, side-to-side anastomosis the diameter of which matches the internal diameter of the target coronary artery. After extensive evaluation in cadaver hearts and animal models [3], the first human implantation was performed successfully in November 2000 in our institution [4]. This article summarizes the present experience in human patients and focuses on some changes that have made the second-generation connector more suitable for clinical use.
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Material and methods
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Description of the devices
First-generation devices
The stainless steel coronary connectors contain hooks that secure the vein graft and also engage the internal lumen of the coronary artery. The first-generation coronary connector system was designed for coronary arteries with an internal diameter of 2.5 mm. The connector is mounted on a balloon that, when pressurized, expands the device, thereby creating the anastomosis. The coronary hooks are covered with a nosecone to protect the artery from injury during delivery. The connector system is loaded through the distal end of the vein graft with the help of a microscope and less than 10x magnification. The external hooks had to be pierced through the vein wall secured the hooks and a small circumferential rubber ring.
Second-generation devices
The loading process is again through the distal end of the vein graft, but it has been significantly simplified and accelerated. The system (Fig 1)
is nearly self loading, such that the connector system has only to be introduced through the preformed hole in the vein. No further hand-piercing of the hooks through the vein wall is necessary, as the angle and shape of the small hooks are adapted for self attachment (Fig 2).
A further advantage is the possible use of the connector in smaller coronary arteries down to an inner diameter of 2.0 mm.
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Fig 1. Distal second-generation St. Jude Medical ATG coronary connector mounted on delivery balloon catheter.
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Fig 2. Loading process for second-generation St. Jude Medical ATG coronary connector. (A) A small hole is made with a blade in the vein. (B) The hole is enlarged with a dilator. (C) The mounted connector is transferred, passing the distal vein end through the prepared hole. (D) Inside view of the preloaded connector.
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First- and second-generation devices
With both systems, the delivery process is comparable (Fig 3).
An arteriotomy is created with a special blade at the planned coronary anastomotic site. The delivery system is introduced, the nosecone advanced, and the balloon inflated, thereby creating a hemostatic seal and firm attachment of the two vessels. The delivery device is then removed and the distal stump of the vein graft closed with clips or sutures (Fig 4).
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Fig 3. (A) Introduction of the connector system into the coronary artery. The plastic nosecone protects the inner hooks of the connector. (B) Advancing the nosecone uncovers the small inner hooks of the connector. (C) The device is placed at a 90-degree angle. (D) Expanding the balloon connects the two vessels. (E) The device is brought back to the insertion angle, and the deflated balloon is removed.
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The clinical protocol for an investigational study with the first- and second-generation connectors for coronary artery bypass grafts was reviewed and approved by the local Ethical Committee in Berne, Switzerland. Informed consent for one mechanical vein graft-to-coronary connection was obtained in all patients.
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Results
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Patients who received a distal coronary connector were operated using standard extracorporeal circulation (ECC) and myocardial protection techniques. Complete revascularization was performed in all cases.
First-generation device
Between November 2000 and June 2001, 14 patients (mean age 63 ± 8 years), received one distal anastomosis with a SVG using the first-generation mechanical device. In this patient group, the external diameter of the target coronary vessels was 3.0 mm or more, resulting in an estimated internal diameter of 2.5 mm or more. In the same series, 9 patients were excluded intraoperatively because of target coronary arteries less than 2.5 mm in outer diameter. Anastomoses with the connector system were performed mainly to the right coronary artery (10 patients) because of these vessel size limitations. Time required to load the vein graft onto the delivery system varied between 6 and 8 minutes and was performed with the help of a microscope. Time to deploy the connector and thereby create the anastomosis was less than 2 minutes. Hemostasis was instantaneous in all cases, and all mechanical anastomoses were patent at the end of the procedure, as confirmed by intraoperative flow assessment with the transit-time method. Postoperative angiography was performed in all patients at the end of the operation. All anastomoses were patent, but retrograde flow to the native coronary artery was restricted in 1 patient. The connector was removed and the anastomosis was performed with a running suture at the same site. Three-month angiography or magnetic resonance imaging angiography follow-up was available in 11 patients; 10 grafts with the mechanical connector were patent, and one was occluded. In 3 patients with a patent graft, some degree of narrowing at the site of the anastomosis was observed. In 1 patient, percutaneous transluminal coronary angioplasty and stent implantation of the native RCA was performed. There were no cardiac-related adverse events or any return of angina. Exercise tolerance tests and stress electrocardiography were normal in all patients [6].
Second-generation device
Between April 2002 and May 2002, in 5 patients (mean age 74 ± 5 years), one distal SVG anastomosis was performed with the second-generation distal connector. In this patient group, the external diameter of the target coronary vessels was 2.5 mm or more and the estimated internal diameter was 2.0 mm or more. Two patients were excluded intraoperatively because of coronary arteries that were too small and 1 patient because of poor vein quality. Connector anastomoses could be performed equivalent to the right and left coronary system (posterior descending artery twice, right coronary artery once, and obtuse marginal branch twice) The time required to load the vein graft onto the delivery system was significantly shorter and was less than 2 minutes in the majority of patients. The loading was always performed in the operating field with the help of 2.5 magnification surgical telescopes. Time to create the mechanical anastomosis at the coronary site was equivalent to that with the first-generation system. Excellent instantaneous hemostasis was obtained in all cases, and all mechanical anastomoses were patent at the end of the procedure as measured by intraoperative flow assessment with the transit-time method.
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Comment
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One of the most recent technological advances likely to have a great impact on the adoption of cardiac bypass surgery is the development of mechanical anastomotic devices to facilitate all vascular connections. Any anastomotic device must be simple to use and must provide precise, effective outcomes [7]. Any potential endothelial damage should be minimized, and the patency rate should be similar to or better than that of sutures. Several anastomotic devices have been proposed to be used even in coronary location, including glues [8, 9], staples [10–12], clips [13], coupling devices [14, 15], intraluminal stents [16], mounting devices [17], laser-assisted procedures [18, 19], and, to a certain extent, the so-called ventriculo-coronary shunts [20, 21]. However, the long-term success of any of these devices has yet to be proved.
The St. Jude Medical ATG coronary connector systems are part of a family of connectors that are made out of stainless steel. They were developed recently to facilitate the creation of a vein graft–to–coronary anastomosis for CABG. Both connectors work on the same technical principle and are mounted on balloon catheters that, when pressurized, expand the connectors and create the anastomosis instantaneously. They produces a round anastomosis that matches the internal diameter of the target coronary artery (Fig 5).
All anastomoses were performed in a side-to-side fashion and the distal end of the graft was then ligated, similarly allowing side-to-side anastomosis in a sequential graft in future. In the first-generation system, one failure occurred in one graft with a unidirectional flow to the distal part and a restricted flow to the proximal part of the coronary artery. This happened early in our experience and was caused by a proximal back-walling of the coronary artery by the internal hooks of the clip. This complication might also develop when the diameter of the target vessel is too small. By reducing the connector sizes to fit on smaller coronary target vessels, the delivery process could become more error prone. Handling of the small device during delivery is more demanding, and includes piercing and dilating the coronary artery. Bail-out of these catheters is possible and was simplified for the second-generation system. Sutured anastomoses can be performed using the same sites with running 7-0 polypropylene sutures, as seen in animal trials. One limitation of the first-generation mechanical connector was the necessity for a target vessel with a 2.5-mm inner diameter, which is not encountered very frequently in the present era of CABG surgery.
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Fig 5. Ex vivo animal model. Three uniform mechanical connections reflecting different connection angles of the veins to the coronary artery. (A) View from the opened vein graft; (B) view from the coronary artery.
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The second-generation system for smaller coronary arteries with an inner diameter of 2.0 mm is currently under multicenter investigation. This connector does not have to be loaded under a microscope and can be loaded over the operating field. This allows combining distal with proximal vein graft connectors to perform totally mechanically connected bypass grafts in the future, as well as its use in arterial grafts. Nevertheless, and in contrast to the use of clips made of metal with memory function (such as Nitinol), the use of stainless steel for coupling devices implies the need for even more careful handling of the system during loading and delivery to avoid irreversible distortion.
These mechanical anastomoses are round rather than oval, leading to the observation at angiography that mechanical anastomoses appear to be smaller (limited by the size of the connector) than hand-sutured ones, and look unusual as a side-to-side connection at the end of the vein graft. The observed smooth narrowing in three anastomoses with the first-generation connector were hemodynamically not restricting. The significance of these findings should be further investigated in the currently ongoing multicenter study of the second generation system and 6-month follow-up results.
There might be some concern with the fact that foreign material is introduced through the intima of the vessels. Although no intimal hyperplasia could be detected in long-term animal trials [3], long-term angiographic follow-up in human patients might uncover such unexpected findings as those seen following stent implantation. Looking at data from animal studies, only a minimal foreign-material surface is visible and in contact with the bloodstream in both generations of St. Jude Medical connectors (Fig 5). Nevertheless, in humans, the need for postoperative medical treatment with either antiplatelet or anticoagulation treatment in patients with any of the various mechanical connectors is still unclear. Completely avoiding contact of the connector with the inner vessel lumen or with any coating or covering might be beneficial for future connector designs.
In conclusion, the St. Jude Medical second-generation coronary connector creates a coronary anastomosis within minimal time and with minimal training requirements. It offers a valuable alternative procedure to the standard suturing technique, not only for coronary artery bypass grafting but also for its potential use in peripheral vascular procedures. Mechanical vascular connections represent another important step in facilitating less invasive cardiac surgery not only through limited access but by enhancing the quality, reproducibility, and rapidity of vascular anastomoses.
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References
|
|---|
- Carrel A. La technique opératoire des anastomoses vasculaires et la transplantation des viscéres. Lyon Med 1902;98:859-863.
- Eckstein F.S., Bonilla L.F., Englberger L., et al. Minimizing aortic manipulation during OPCAB using the Symmetry Aortic Connector System for proximal vein graft anastomoses. Ann Thorac Surg 2001;72:S995-998.[Abstract/Free Full Text]
- Eckstein F.S., Bonilla L.F., Englberger L., et al. The St. Jude Medical Symmetry Aortic Connector System for proximal vein graft anastomoses in coronary artery bypass grafting. J Thorac Cardiovasc Surg 2002;123:777-782.[Abstract/Free Full Text]
- Schaff H.V., Zehr K.J., Bonilla L.F., et al. An experimental model of saphenous vein-to-coronary artery anastomosis with the St. Jude Medical Stainless Steel Connector. Ann Thorac Surg 2002;73:830-835.[Abstract/Free Full Text]
- Eckstein F.S., Bonilla L.F., Meyer B., et al. Sutureless mechanical anastomosis of a saphenous vein graft to a coronary artery with a new connector device. Lancet 2001;357:931-932.[Medline]
- Eckstein FS, Bonilla LF, Englberger L, et al. First clinical results with a new mechanical connector for distal coronary artery anastomoses in CABG. Circulation (in press)
- Werker P.M., Kon M., et al. Review of facilitated approaches to vascular anastomosis surgery. Ann Thorac Surg 1997;63:S122-127.
- Dumanian G.A., Dascombe W., Hong C. A new photopolymerizable blood vessel glue that seals human vessel anastomoses without augmenting thrombogenicity. Plast Reconstr Surg 1995;95:901-907.[Medline]
- Gundry S.R., Black K., Izutani H. Sutureless coronary artery bypass with biologic glued anastomoses. Preliminary in vivo and in vitro results. J Thorac Cardiovasc Surg 2000;120:473-477.[Abstract/Free Full Text]
- Androsov P.I. New method of surgical treatment of blood vessel lesions. AMA Arch Surg 1956;73:902-910.
- Chavanon O., Perrault L.P. Favorable aspect of stapled anastomosis: an endothelial function study. Ann Thorac Surg 1999;68:1443-1444.[Free Full Text]
- Inokushi K. Stapling device for end-to-side anastomosis of blood vessels. Arch Surg 1961;82:337-341.
- Nataf P., Hinchliffe P., Manzo S., et al. Facilitated vascular anastomoses: the one-shot device. Ann Thorac Surg 1998;66:1041-1044.[Abstract/Free Full Text]
- Sasson H.N., Stofman G.M., Berman P. Clinical use of the 3M 2.5 mm mechanical microcoupling device in free tissue transfer. Microsurgery 1994;15:421-423.[Medline]
- Shennib H., Korkola S.J., Bousette N., et al. An automated interrupted suturing device for coronary artery bypass grafting. automated coronary anastomosis. Ann Thorac Surg 2000;17:312-318.
- Solem J.O., Boumzebra D., Al-Buraiki J., et al. Evaluation of a new device for quick sutureless coronary artery anastomosis in surviving sheep. Eur J Cardio-thoracic Surg 2000;17:1046-1048.
- Scheltes J.S., Heikens M., Pistecky P.V., et al. Assessment of patented coronary end-to-side anastomotic devices using micromechanical bonding. Ann Thorac Surg 2000;70:218-221.[Abstract/Free Full Text]
- Mc Carthy W.J., LoCicero J., Harzt R.S., et al. Patency of laser assisted anastomoses in small vessels: one year follow-up. Surgery 1987;102:319-326.[Medline]
- Bass L.S., Treat M.R., Dzakonski C., et al. Sutureless microvascular anastomosis using the THC. YAG laser: a primarily report. Microsurgery 1989;10:189-193.[Medline]
- Tweden K.S., Eales F., Cameron J.D., et al. Ventriculocoronary artery bypass (VCAB), a novel approach to myocardial revascularization. Heart Surg Forum 2000;3:47-54.[Medline]
- Emery R.W., Eales F., Van Meter C.H., Jr, et al. Ventriculocoronary artery bypass results using a mesh-tipped device in a porcine model. Ann Thorac Surg 2001;72:S1004-1008.[Abstract/Free Full Text]
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Top
Abstract
Introduction
