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Ann Thorac Surg 2004;77:1110-1120
© 2004 The Society of Thoracic Surgeons
a Clinic for Cardiovascular Surgery, University Hospital, Berne, Switzerland
* Address reprint requests to Dr Carrel, Clinic for Cardiovascular Surgery, University Hospital Berne, CH-3010 Berne, Switzerland
e-mail: thierry.carrel{at}insel.ch
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Abstract |
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 Top Abstract IntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Introduction |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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| Dr Carrel discloses that he has a financial relationship with St. Jude Medical.
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During more than three decades coronary artery bypass grafting (CABG) has been performed through full sternotomy with the aid of extracorporeal circulation and cardioplegic arrest as the treatment of choice for patients suffering from multi-vessel coronary artery disease (CAD). Many patients who undergo this procedure today are older and sicker than in the past. For this reason, the success of a CABG procedure can no longer be measured by whether or not the heart is completely revascularized, but operative complications, should be considered [1–3].
Smaller incisions reduce the trauma of operation as does the avoidance of cardiopulmonary bypass (CPB) [4–7]. These approaches may lead to incomplete revascularization or decrease anastomotic quality during off-pump coronary artery bypass (OPCAB) which may be resulting in reinterventions.
Vascular connections in CABG require running or interrupted sutures, a technique described in 1904 [8]. In small vessels these techniques are demanding, time-consuming, and carry a learning curve but are adaptable to anatomic variations and vessel disease to achieve excellent patency. Now new devices to rapidly and reliably connect bypass grafts to the aorta and the coronary artery are available and in development. These connectors make use of staples, clips, glue and laser assisted systems, and suture-based automated technology and coupling devices are available for research and/or clinical use. Several reviews have not fully addressed the issues related to these devices [9, 10] which has led to this report.
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Devices for proximal anastomosis (aorta to bypass graft) |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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St. Jude proximal connector
The SymmetryTM Aortic Connector System first generation is part of a family of connectors from St. Jude Medical (SJM, St. Paul, MN) and is made of nitinol. The connector is selected by vein graft diameter. The vein is slid over a transfer sheet that facilitates the loading process on the release tube. Care must be taken that the vein does not dry. Adventitia is removed from the end of the vein which is loaded on the delivery system with the hooks of the connector penetrating the wall of the vein to prevent dislocation of the graft during deployment. To avoid the formation of intimal flaps the cutting blade should be maintained at a 90° angle to the aorta. Neither creating the neo-ostium nor delivering the device require tangential clamping of the aorta. The optimal mean arterial pressure during delivery is around 50–60 mm Hg (systolic pressure ideally not over 100 mm Hg). The system uses a unique rotating blade that creates a perfectly round hole without damaging the adjacent aortic wall. Delivery takes less than 10 s. Hemostasis is perfect and instantaneous. In case of anastomotic leakage placement of an adventitial extra-stitch can be performed but is not recommended by the company. Healing process in animal testing showed no intimal hyperplasia but only a thin layer of neointima covering the connector device after 6 months [12].
Since receiving CE market and FDA approval in May 2001, more than 40,000 SymmetryTM Aortic Connector Systems have been used worldwide but there is no consistent information about patency rate reported.
We have reviewed our clinical experience with 107 patients who received at least one proximal SymmetryTM aortic connector with at least 6 months of follow-up [13]. Of the 107 patients, 75 were part of an observational study and 32 were enrolled in a prospective randomized study to compare the anastomotic device with the conventional suture technique. Hospital mortality was 0.9% (1/107). Two connectors had to be removed because of leakage and one because of incomplete deployment. The 104 grafts were patent at the end of the operation (mean flow 72 ± 29 ml/min). In 14 patients from the randomized study the 6 months angiographic control assessed 42 grafts. All internal mammary artery (IMA) grafts (n = 14) were patent and 3/4 radial artery grafts were patent. Of 24 vein grafts, 11 were hand-sewn and 13 were anastomosed with the connector. Patency rate was not different between the two techniques but there was a 38% (5/13) incidence of stenosis in the proximal vein graft segment with the connector. No proximal hand-sewn anastomosis showed any significant stenosis.
In the absence of more definitive data we are currently using this device in selected situations such as calcified ascending aorta with small soft spots, reoperative CABG with limited access to the ascending aorta, and in OPCAB when expedient surgery is required. In one patient, we have used this system to connect a vein graft to the abdominal aorta in a difficult situation of redo-surgery to revascularize the superior mesenteric artery [14].
Clinical experience has been reported by several groups. In 10 patients one proximal vein graft anastomosis was performed with suture and the second with the connector. One sutured graft had a significant stenosis and one connector anastomosis was occluded; overall patency rate was 90% in this small series [15].
Traverse and coauthors reported recently clinical, angiographic and interventional follow-up of 74 consecutive patients who received the symmetry connector system. A total of 131 of 144 proximal vein graft anastomoses were performed with this device. A total of 11 patients were readmitted with chest pain consistent with unstable angina 173 ± 39 days after CABG. At angiography, 20 saphenous vein bypass grafts containing 19 connectors were found to have severe stenosis (n = 12) or occlusion (n = 6), and were treated with angioplasty and stenting or medical therapy [16]. Out of a series of 206 connectors deployed in 132 patients technical problems arose in 5.5% of the cases and postoperative angiography in 19 patients at a mean interval of eight weeks revealed occlusion of 4/32 grafts (12.5%) although intraoperative transit time flow measurement was satisfactory in all cases [17].
Donsky described two cases of acute thrombosis of the aortic ostia with the St. Jude connector [18]. They hypothetized that this complication may have similar pathophysiology to that seen in acute stent thrombosis. The best postoperative medical treatment is still unclear; some centers have adopted the use of clopidogrel (75 mg daily) as a routine for the first 3 months whereas others use aspirin (300 mg) only.
There are several critical points concerning the first generation of proximal connectors. The mounting of the vein over the deployment device is one of the most critical steps for the quality of the connection; inaccurate mounting could end up with anastomotic leakage or with a stenotic connection. With this device the proximal anastomosis has to be performed first which means a change for a majority of surgeons. The design of the connector implies a 90° take-off angle of the vein graft from the ascending aorta. This means that the anterior surface of the ascending aorta should be avoided because of the risk of kinking and compression by mediastinal tissue and the sternum. The optimal length of the vein has to be evaluated very precisely to avoid kinking of the graft or tension on the connector.
To address some limitations and pitfalls of the first generation proximal connectors, the ATG group of St. Jude Medical developed a second generation system with the following main changes. First the concept allows a side-to-side anastomosis without manipulations in the vein graft during the loading process. Second, there is no concern about the take-off angle in this configuration. Third there is a fixed size of the connector as compared to self-expansion with the first generation device. A sizing/incision tool is advanced 1–3 cm into the proximal end of the graft. A scalpel blade is use to create an opening in the side wall of the graft at the anastomosis site; the delivery system, with the premounted connector, is then placed in this aperture. The attachment knob of the delivery system is then rotated to release the connector graft hooks thereby securing the graft to the connector. The delivery system is then introduced into the target aortic site (cutting process same than with first generation system). The delivery system handle push button is pressed and the delivery system is removed. The graft stub end is ligated or clipped (Figs 1 and 2). A prospective multicenter trial of this system is underway. Preliminary results seem to be better than those of first generation.
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The CorLink device
The Aortic Anastomotic Device (AAD Bypass, Ltd, Herzelia, Israel) which has been commercialized by J&J Ethicon (Cardiovations, a company of Ethicon, Somerville, NJ) allows creation of an anastomosis between the ascending aorta and a saphenous vein graft. The AAD is a self-expanding nitinol extraluminal device that consists of a central cylindric body made of interconnected elliptical arches and two sets of five pins radiating from each end. The graft is pulled through the inserter by means of a snare or a 4.0 suture passed through the adventitia. The vein graft has to be everted over the distal end of the system.
The five intimal pins are deployed from the cardridge of the delivery system, making them protrude and penetrate the everted segment of the vein. Full penetration of the pins through the vein tissue is a mandatory precondition for a successful procedure. A special punching instrument is inserted in the handle and creates a round hole in the unclamped aorta. After punching, the punch cone is driven into the aorta while the device is rotated 360° in both directions to ensure a complete punching. The punching device is withdrawn from the handle and the delivery system is advanced into the aorta and the AAD is released. At this time the inner pins partially penetrate the aortic wall whereas the outer pins stabilize the device by anchoring into the aortic adventitia. The inserter together with the overtube split open and release the anastomosed vein graft.
In the initial feasibility trial 17 patients were selected to receive one proximal anastomosis using this device. In one patient the device was not deployed and in 2 patients an additional suture was necessary to achieve perfect hemostasis. There was no mortality nor device-related morbidity in this series and in 6 patients control angiogram showed patent anastomosis after a mean follow-up of 48 days [19].
In a small prospective randomized trial Riess compared 11 patients with at least one CorLink device and with 10 control patients. In one case eversion of the vein graft was not possible and in 2 patients additional sutures were necessary to control minor anastomotic leakage. In the same group one patient had a myocardial infarction and another one had to be reoperated because of a kinked internal thoracic artery (ITA) graft. Multislice CT-scan showed that all grafts were patent at 6 months [20].
The amount of foreign material presented to the blood flow is rather small; the stent is completely covered by the everted saphenous vein; most probably no or only very limited intimal hyperplasia has to be expected because the inner pins of the device are fixed to the intima of the inner aortic wall and not within the proximal graft anastomosis.
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Devices for distal anastomosis (bypass graft to coronary artery) |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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After extensive animal testing [21] we have evaluated both generations of distal connectors. A prospective nonrandomized, open label, single center feasibility trial started in November 2000 [22–24]. With the first generation hemostasis was instantaneous in all cases but within the second generation (easy loading), one of five had to be removed because of leakage. Three month angiography was available in 11 patients with 10 patent first generation connector grafts. The second generation connector is being investigated invasively after a mean follow-up of 6 months. There was no cardiac-related event nor return of angina and exercise tolerance tests were negative in all patients.
In contrast to other systems (for instance U-clips) the use of stainless steel for coupling devices implies the need for more careful handling of the system during loading and delivery to avoid irreversible distorsion. The distal anastomoses performed with the coronary connector from St. Jude are round rather than oval leading to the angiographic observation that these anastomoses appear to be smaller than hand-sewn ones.
The HeartFloTM automated device
The HeartfloTM (Perclose/Abbott Labs, Redwood City, CA) anastomotic device was considered one of the most promising surgical tools to facilitate end-to-side and side-to-side interrupted suture anastomoses for CABG. It is a multi-suture anastomotic device consisting of a hydraulically activated delivery mechanism and two branches with each branch housing needles and the opposite ends of ten 7.0 polypropylene sutures. The arteriotomy in the target coronary artery is made with HeartfloTM scissors that make a 4 mm incision. The device first simultaneously delivers ten sutures of one branch through the wall of the graft conduit and then through the wall of the coronary artery at an appropriate distance from the edges of 1–2 mm. The ends of the ten sutures are then sorted and pulled to approximate the graft to the coronary artery. The surgeon manually ties off the ten sutures to complete the anastomosis, similar to a hand-sewn interrupted anastomosis.
In a feasibility animal trial mean time required to complete the anastomosis was 22 minutes and 6 of 8 anastomoses were hemostatic whereas two required an additional stitch [25]. The next generation has already been assessed in humans and addressed some of the limitations which include ability to access and maneuver in deep vessels, tissue capture, and deployment consistency. Despite extensive animal testing, feasibility still has to be demonstrated. In one series failure to complete the anastomosis with the device occurred in 10/30 patients and 11/16 anastomoses which were completed required an average of 1.7 ± 0.3 additional stitches were necessary because of minor leakage [26]. Unfortunately only one patient underwent postoperative coronary, angiography. In the second series additional stitches were necessary in the majority of patients (8/13 anastomoses required more than two stitches for adequate hemostasis) [27]. In addition the time to complete the anastomosis varied between 15 and 22 minutes.
The success of this device is yet to be established and the main limitation is the achievement of optimal tissue capture which can be reduced when the incision is too large or if vessel wall irregularities (deposits and calcifications) are present at the anastomosis. There is no time gain and the handling of the sutures is cumbersome. The only advantages of the system are that the device uses the well-known material polypropylene and that no endovascular material is left. Disturbing is the fact that in all three papers the authors describe the system as simple, safe, effective and/or promising, This constrasts deeply with the high technical failure rate, the need for additional sutures, and the lack of angiographic follow-up.
The Solem Graftconnector
A nickel–titanium coronary stent covered with PTFE (Jomed International, Helsingborg, Sweden) was used to connect the internal thoracic artery to the left anterior descending coronary artery (LAD) in sheep [28]. The stent represents the sleeve of the Graftconnector. Asymmetrically the stent has an opening in the circumference. The side branch (called the tower) is where the conduit will be attached. The sleeve of the Graftconnector may be placed inside the target coronary vessel (Fig 5). The memory metal alloy of the sleeve exerts a radial force that tends to open the sleeve. This force is used to fixate the connector inside the coronary artery once it is in place. A feasibility study was performed with promising results [29]. However the manipulation is cumbersome, the covered stent may cover side branches, and there is the potential of in-stent stenosis. Compromising the best conduit available with this connector makes no sense when conventional anastomosis is proven.
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Although the system is based on an ingenious but simple mechanism careful attention has to be paid that no excess tissue is overlapping the internal magnets. Some disadvantages are that use is limited to large and disease-free target vessels and visualization of the anastomotic site during loading, deployment, and final attraction of the magnetic ports is not comfortable. Lack of information does not allow a definitive judgement about potential of the device.
Combined anastomotic device and tissue adhesive
The group of Gründeman and Borst from Utrecht developed a hybrid anastomotic technique that combines micromechanical coupling and adhesive binding without any need for dedicated application tools. Feasibility was assessed using an extraluminal frame and octyl–cyanoacrylate tissue adhesive during off-pump, porcine, left internal thoracic artery to right coronary artery bypass grafting [32]. The device consists of a stainless steel ring and four axially extending elastic bendable hook elements with thickening at the ends. The end of the graft is passed though the orifice of the ring, everted, and impaled over the hook elements. Thickenings near tips of the elements prevent the graft from sliding upward. Four radially expanding elastic hook elements bring the internal thoracic artery and the coronary artery into proper fixed apposition after which the slightly stretched anastomotic quadrants are consolidated with adhesive. The mounted crinoline is hooked to a coronary artery in intima–intima apposition of graft and recipient artery. The anastomotic line of end-to-side anastomosis is slightly stretched after which fixed apposition is consolidated by adhesive.
At five weeks all anastomoses were patent with minor narrowing in some cases. In 6 of 8 anastomoses complete intima–intima apposition was established along the full circumference. The authors concluded that extraluminal frame structures are relatively easy to apply and minimize foreign-body exposure to the blood. A full view of every anastomotic quadrant facilitates proper positioning. In case of misalignment repositioning of one or more hook elements requires little time. Some limitations were addressed, e.g., by critical arteriotomy length, external ring frame too high, and the fact that the adhesive is approved for topical wound closure only.
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Devices for proximal and distal anastomoses |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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The principle of staples and clips was re-introduced by Kirsch in 1992 for intimal approximation in microvascular anastomosis and has been performed experimentally and clinically both in the coronary and peripheral circulation [38, 39].
More recently an experimental trial assessed the feasibility of constructing a coronary end-to-side anastomosis on the beating heart with a novel mechanical sutureless device (One-shot, US Surgical Corporation, Norwalk, CT) that circumferentially applies 12 clips simultaneously [40]. Endothelial denudation, medial necrosis, and intimal hyperplasia were analyzed quantitatively and compared to those seen following conventionally sutured anastomoses. Successful application was performed in 8/14 patients. In 6 patients malaligned clips had to be replaced manually. In spite of early endothelial and medial damage all anastomoses remained patent with minimal intimal hyperplasia at 4 weeks.
The U-Clips
Interrupted suture techniques avoid the purse-string and puckering effects that might be observed with continuous suture technique and to some extent they should represent the standard of care in the creation of high-quality vascular anastomosis. The impact of an interrupted suture technique on the quality of the anastomosis was demonstrated almost two decades ago by the Cleveland Clinic group [41]. Broad adaptation of the interrupted technique has been inhibited by the increased procedural complexity and time associated with the knot tying.
The U-ClipTM (Coalescent Surgical, Sunnydale, CA) brings a new level of accuracy, precision, and control to the anastomotic process [42]. It features a simple yet elegant design that eliminates the usual suture management and knot tying. The device consists of a self- closing clip fabricated from a shape memory nitinol which is attached to a conventional suture needle through a flexible suture-like nitinol member. The U-clip is placed via a conventional needle. Squeezing the release mechanism, that is immediately adjacent to the clip, with the needle-holder separates the member and releases the clip allowing it to immediately recoil to its preferred closed-loop configuration. The nitinol wire, once detached from the flexible member, functions to approximate and hold tissue together similar to an interrupted suture. The superelastic properties of the nitinol wire are used to allow precise delivery and positioning of the clip and produce strong but atraumatic tissue approximation. The anastomosis is performed in a usual fashion with clips applied progressively around the anastomosis.
We have used U-clips to perform proximal and distal coronary anastomoses with all types of conduits during CABG as well as for arterial and venous anastomoses in pediatric cardiac surgery, for arterio-venous hemodialysis shunt, and for peripheral vascular anastomoses [43, 44]. Anastomotic time is similar to or less than that for continuous suture anastomosis. The manufacturer estimates that 50,000 CABG anastomoses have been completed with the U-clip. Clinical patency has been excellent and the ratio of anastomotic diameter to the LAD diameter was good (1.17, ranging from 0.93–1.93) [45, 46].
Previous studies have shown that interrupted anastomoses are the least restrictive and consistently produce an internal configuration with minimal deformity and the potential for increased flow rates, compliance, and growth [47–49]. Thus clips or interrupted sutures may be of particular value in pediatric cardiac surgery helping to preserve growth potential and prevent anastomotic stricture and late stenosis. Because of elimination of knot-tying the U-clip may also be suitable for minimally invasive, thoracoscopic, and robot-assisted procedures [50, 51].
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Alternative procedures |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Laser-assisted procedures |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Comment |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Industry is clearly driving the development and application of these devices while arguing that these systems may enhance the continued adoption of less invasive techniques currently used for CABG surgery. So far there has been no evidence that using these devices speeds the anastomosis, particularly when the set-up time is included; furthermore none of the clinical trials have been able to demonstrate superior patency.
New technologies are presently developing faster than the profession's ability to provide evidence-based data to support their application [61]. The American College of Surgeons addressed the need to protect patients while promoting scientific progress: "It is equally essential that the value and safety of a new procedure be established before it is widely used on patients" [62]. Historically, a majority of anastomotic devices used in CABG surgery and those being introduced in clinical trials and/or marketed have not been preceded by conclusive statements on long-term efficacy and safety. Of course exagerated regulation can threaten the development of new technologies by intimidating potential innovators, but, on the other side, new procedures and significant changes in conventional ones should not be adopted before they have been tested under controlled conditions and proved to be safe and effective.
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Optimal standard myocardial revascularization |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Potential advantages |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Cross-clamping and tangential clamping of the ascending aorta may lead to aortic wall trauma such as acute dissection [65, 66] and local particulate embolization [63, 64] which results in transient cerebral ischemia or stroke. In that context proximal devices reduce aortic manipulation and therefore neurological complications [11].
Closed chest procedures using robotics for CABG are expensive procedures that require a long surgical learning curve because of the limited space in the operating field and the training required to carry out the technical manipulations [50, 51, 67, 68]. In particular using robotics for the sewing of the coronary anastomosis during closed chest CABG is challenging and time-consuming: anastomotic devices may simplify the technique of creating endoscopic vascular anastomoses.
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Potential disadvantages |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Of course any device should match at least the quality standards of the conventional suturing techniques in term of simplicity, safety, and long-term patency [68]. Some disadvantages may still be the complexity of the handling, the difficulty of use in difficult access target areas, and the absence of versatility (sequence of performing proximal and distal anastomosis not interchangeable). Most distal devices work only under the best of all circumstances, that is, in larger vessels (e.g. >1.5–2.0 mm) that have no disease. In clinical practice most target vessels will not fulfill these criteria. In addition a majority of devices are restricted to the use of vein grafts which is not the goal that surgeons should follow. Data are lacking data about the safety of bail out; whereas some devices can be removed without difficulty, others may leave some damage on the target artery.
The potential for endothelial injury during the loading process with the proximal SymmetryTM first generation device has been recognized by Yau and colleagues. This could lead to intimal hyperplasia and negate the advantages of some devices. Therefore these authors analyzed the endothelium-dependent and independent function in human saphenous vein grafts loaded on the delivery system. Surprisingly, the loading process did not impair responses to A23187, an endothelium-dependent nitric oxyde mediated vasodilator [69].
One disadvantage is the high cost associated with the use of any connecting device system and whether the additional cost can be offset with shorter procedural time, accelerated recovery, or improved outcome which has not yet been demonstrated. However at an estimated price of $300–500 per device and with 2–4 bypass grafts per CABG patient the market for these devices may rival that of coronary stents. As new technologies go through clinical trials and prove their benefit toward patient outcomes, clinicians have to find out ways to offset the cost of this new technology, for instance by eliminating unnecessary costs within current patient care throughout the entire patient hospital stay.
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Evaluation and validation of devices for facilitated vascular anastomoses |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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Borst and colleagues have developed the BENIS (blood exposed nonintimal surface) concept to compare the blood exposed nonintimal surface in the anastomosis constructed with different connecting devices with the BENIS area in the hand-sewn anastomosis. In most device-constructed anastomosis configurations, the estimated minimal BENIS area ranged from 1–6 mm2, but was as high as 85 mm2 in one system, which means that a large amount of foreign material is exposed to the blood stream [72]. In contrast the conventionally hand-sewn anastomosis shows a BENIS area of approximatively 1.3 mm2. Therefore large differences in potentially thrombogenic estimated BENIS area were found which are related to the location and size of the bonding components and to the size of the anastomotic orifice. Unfortunately the BENIS concept has not been adopted so far by the developing companies.
At the end of this review the reader should recognize that there is an urgent need to define standards and guidelines for a homogenous evaluation of all devices for facilitated anastomosis in coronary surgery. We need a consensus paper to define standards and assist industry in bringing new devices to market. Minimal safety and efficacy requirements for in vitro and in vivo animal studies as well as what is acceptable when bail out of the device is necessary because of technical failure or maldeployment should be defined. A standard animal model with each device subjected to similar follow-up periods is needed to offer reliable comparisons between devices before they are accepted for clinical use.
Looking at the excellent long-term patency rate of the ITA sutured in a conventional way to the LAD it is unacceptable to test new devices with unknown long-term patency in this context (ITA and LAD). Therefore the ideal target vessels to test devices should be defined uniform. The concept should be analyzed for potential application to diseased arteries, the need for additional stitches, and the pressure at which anastomotic bursting would happen. Preclinical validation should be performed in atherosclerotic in vitro human cadaveric heart or in vivo atherosclerotic animal models. Final validation should be performed in a beating heart model and later in a limited working space model.
The optimal postoperative anticoagulation treatment and the assessment of patency rate at different intervals during follow-up have to be harmonized. Although CT-scan, MRI, and electron beam angiography are helpful, conventional angiography still represents the gold standard to demonstrate graft patency and to detect possible stenosis and it also offers the additional possibility of percutaneous interventions when required [13, 73]. Qualitative and quantitative methods should be used to evaluate each anastomosis. Whereas qualitative methods would include estimates of TIMI flow grade and general assessment of patency, quantitative evaluation includes assignment of a FitzGibbon score [74]. Finally precise assessment of the luminal diameter of the target coronary artery and of the graft proximal and distal to the anastomosis as well as the diameter of the anastomosis itself would allow to calculate the ratio of the anastomosis to the coronary artery and also the average percent diameter stenosis.
For all these reasons the acceptance of these devices has been modest even if the creation of a coronary anastomosis within seconds is an exciting perspective.
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Acknowledgments |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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References |
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TopAbstractIntroductionDevices for proximal anastomosis...Devices for distal anastomosis...Devices for proximal and...Alternative proceduresLaser-assisted proceduresCommentOptimal standard myocardial...Potential advantagesPotential disadvantagesEvaluation and validation of...AcknowledgmentsReferences |
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K. E. Matschke, J. F. Gummert, S. Demertzis, U. Kappert, M. B. Anssar, F. Siclari, V. Falk, E. L. Alderman, C. Detter, H. Reichenspurner, et al. The Cardica C-Port System: Clinical and angiographic evaluation of a new device for automated, compliant distal anastomoses in coronary artery bypass grafting surgery--A multicenter prospective clinical trial J. Thorac. Cardiovasc. Surg., December 1, 2005; 130(6): 1645 - 1652. [Abstract] [Full Text] [PDF]
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U. Klima, T. Kofidis, A. Boening, and A. Haverich Long term angiographic monitoring reveals safety and efficacy of the Converge end-to-side anastomotic coupler Interactive CardioVascular and Thoracic Surgery, December 1, 2005; 4(6): 505 - 508. [Abstract] [Full Text] [PDF]
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D. Y. Loisance, K. Nakashima, and M. Kirsch Computer-assisted coronary surgery: lessons from an initial experience Interactive CardioVascular and Thoracic Surgery, October 1, 2005; 4(5): 398 - 401. [Abstract] [Full Text] [PDF]
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B. Akpinar, M. Guden, E. Sagbas, I. Sanisoglu, M. U. Ergenoglu, and C. Turkoglu Clinical experience with the Novare Enclose II manual proximal anastomotic device during off-pump coronary artery surgery Eur. J. Cardiothorac. Surg., June 1, 2005; 27(6): 1070 - 1073. [Abstract] [Full Text] [PDF]
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A. Boening, F. Schoeneich, A. Lichtenberg, E. Bagaev, J. T. Cremer, and U. Klima First clinical results with a 30{degrees} end-to-side coronary anastomosis coupler Eur. J. Cardiothorac. Surg., May 1, 2005; 27(5): 876 - 881. [Abstract] [Full Text] [PDF]
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