Ann Thorac Surg 2005;80:695-699
© 2005 The Society of Thoracic Surgeons
New technology
The Second-Generation Aortic Connector: Six Months’ Angiographic Follow-Up
Marek Setina, MD
a
,
*
,
Adriana Krchnakova, MD
a
,
Ales Mokracek, MD
a
,
Ladislav Pesl, MD
a
,
Luis F. Bonilla, MD
b
a Department of Cardiovascular Surgery, Ceske Budejovice Hospital, Ceske Budejovice, Czech Republic
b St. Jude Medical Anastomotic Technology Group, Minneapolis, Minnesota
Accepted for publication August 23, 2004.
* Address reprint requests to Dr Setina, Department of Cardiovascular Surgery, Ceske Budejovice Hospital, Bozeny Nemcove 54, Czech Republic 37087 (Email: setina{at}nemcb.cz).
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Abstract
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PURPOSE: Recently, new mechanical anastomotic devices have been developed. Initial results appear to be equivalent to those obtained with suture. The aim of the study was to evaluate the 6-month angiographic patency and clinical results with the St. Jude Medical second-generation aortic connector for proximal aortosaphenous graft anastomosis.
DESCRIPTION: From September 2002 to June 2003, 45 connectors were implanted in 39 patients. Thirty-three patients with 36 connectors underwent 6-month angiographic and clinical follow-up.
EVALUATION: One connector had an early occlusion and 2 connectors and 1 vein graft were occluded at 6-month angiography, for a patency rate of 88.9% (32 of 36). No device-related complications were detected at 6-month follow-up.
CONCLUSIONS: The second-generation aortic connector is safe and easy to use. Preliminary results show no device-related complications and a satisfactory 6-month angiographic patency.
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Introduction
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| Doctor Bonilla discloses that he has a financial relationship with St. Jude Medical.
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Recently, clinical and angiography results with the first generation of the St. Jude Medical (SJM) symmetry aortic connector system for proximal vein graft-to-aorta anastomoses have been described [1–5].
Initial results were satisfactory but, lately, some complications have been reported [6, 7]. The SJM second-generation aortic connector has been developed to overcome some of the disadvantages of the first generation. We report the first clinical and angiographic results with this device.
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Material and Methods
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The study was approved by the local ethics committee of the Ceske Budejovice Hospital (June 2002) and by the Ministry of Health of the Czech Republic. Each patient enrolled in the study signed an informed consent form. The investigated device received the CE Mark for the European Union in October 2003.
From September 2002 to June 2003, 45 connectors were implanted and nine hand-sewn proximal anastomoses were performed in 39 patients (33 men, 6 women; mean age 62.5 ± 8.0 years).
Four patients (having five connectors implanted) were excluded intraoperatively for technical reasons. We used two connectors for marginally small diameter vein grafts in the first patient. The underestimation of the graft’s diameter caused back-walling at the connector anastomoses, and we had to remove both connectors. Owing to a thick aortic wall in the second patient, the connector pulled down the vein into the aortotomy. After removal of the connector, we found the aortic wall was approximately 6 mm thick. Leak from the connector anastomosis developed in the third patient. The reason for the leak was most likely improper loading of the vein graft onto the small hooks penetrating the vein wall and fixing it into the connector. We did not try to repair the leak and decided to remove the connector. In the last patient, we accidentally removed a successfully implanted connector during manipulation of the heart while performing the distal anastomosis. The connectors were removed without complications in all these patients. and the procedures were finished using conventional suturing technique.
Because we were using a new device under investigation, we performed 38 of the 39 operations with the use of extracorporeal circulation (ECC). Only 1 patient with very suitable anatomy was operated on without the use of ECC. The mean blood pressure of 50 mm Hg was maintained during firing the connector into the aorta. The only arterial graft used in this study was left internal mammary artery (LIMA), which was used in all patients.
Thirty-three patients with 36 connectors underwent angiographic and clinical follow-up at a mean of 6 months (range, 5 to 7).
Angiography results were evaluated by an independent core laboratory (PERFUSE Angiographic Core Laboratory and Data Coordinating Center, Boston, MA) where connector grafts were evaluated for patency. The thrombolysis in myocardial infarction (TIMI) flow grade (TFG), corrected TIMI frame count (CTFC), TIMI myocardial perfusion grade (TMPG), and quantitative coronary angiography were performed for graft stenosis evaluation.
Intraoperative graft flow measurements were performed in 34 connector grafts, using an 8 MHz Doppler flow probe (Medi-Stim Butterfly Flow Meter; Medi-Stim AS, Oslo, Norway).
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Design of Connector and Delivery Technique
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The device is made of nickel-titanium (Nitinol) and is designed to create a side-to-side (functionally end-to-side) anastomosis (Fig 1). The side-to-side technique was chosen because it provides an optimal take-off angle to prevent kinking and enables performing distal anastomoses first. The connector system includes the following components: (1) loaded delivery system, (2) aortic cutter, and (3) sizing tool.
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Fig 1. The second-generation aortic connector. The struts position the connector in the aorta, and small hooks fix the vein.
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After harvesting the vein graft, the inside diameter of the proximal end of the vein graft is measured with the sizing tool. The device is available in four sizes, ranging from 3.0 to 5.0 mm, based on the inside diameter of the vein graft.
In few simple steps, the graft is loaded into the delivery system (Figs 2
and 3). The anastomosis is created in a way very similar to that used with the first generation connectors. After connector expansion, the delivery system is removed, and the proximal vein graft stump is ligated (Figs 4
and 5).
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Fig 5. Saphenous vein graft attached to the aorta with the connector. Left arrow indicates the anastomosis; right arrow indicates ligated proximal stump of the vein.
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Because of the side-to side anastomosis configuration, the best location for the anastomosis is on the anterior part of the ascending aorta. Location selection is important to avoid kinking of the graft. The aortic connector should not be used in portions of the aorta where conventional surgical anastomoses would not be performed because of aortic disease.
Except for the creation of the proximal connector anastomosis, the operation is conducted using conventional techniques.
The postoperative antiplatelet regimen was aspirin (100 mg per day), which is the standard protocol used in our department. No other platelet inhibitors or anticoagulants were used postoperatively.
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Results
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All results are expressed as mean ± standard deviation. The mean connector graft flow was 57.2 ± 29.2 mL/min. Hospital mortality rate was 2.6% (1 of 39). One patient with a low ejection fraction died on postoperative day 6 of multiorgan failure. Postmortem examination showed two widely patent connector grafts. Freedom from major perioperative complications was 94.9% (37 of 39). One patient had pneumonia with respiratory failure requiring prolonged ventilatory support, and 1 patient had prolonged wound healing owing to superficial sternal wound infection. No patient presented with postoperative neurologic complications. There were no myocardial infarctions, reoperations for bleeding, or other complications.
The total number of patients enrolled in the study was 39 (with 45 connectors implanted). 4 patients (with 5 connectors implanted) were excluded from the study because of the removal of the connectors intraoperatively for technical reasons. One patient (with 2 connectors implanted) died, and 1 patient (with 2 connectors implanted) refused the 6-month angiography. Nevertheless, he underwent 6-month clinical follow-up. He was feeling well and did not have any signs of ischemia. Thirty-three patients with 36 connectors implanted underwent the 6-month follow-up.
Freedom from major adverse events was 90.9% (30 of 33 patients). In the first patient, the flow through the connector graft was not detecable by the flow meter in the operating room after terminating ECC. Because the quality of vein graft was marginal, the target coronary artery was diseased, weaning from the ECC was smooth, and the patient was hemodynamically stable without inotropic agents or changes in the ECG suggestive of ischemia, the connector graft was not revised, and the chest was closed. Owing to high suspicion of graft closure, an angiogram was performed at 6 days after surgery, and the connector graft was found to be occluded. A patent LIMA enabled a safe angioplasty of the native coronary (obtuse marginal branch) without complications. He was doing well at the 6-month clinical follow-up. We did not perform angiography, but this patient was included in the group of patients with an occluded connector. Another patient had endocarditis of the native aortic valve 5 months after surgery. Angiography showed two widely patent connector grafts, and the patient underwent uneventful aortic valve replacement. In a third patient, angina pectoris developed 5 months after surgery. Angiography showed a patent connector graft and occlusion of the LIMA to the left anterior descending artery. Successful angioplasty of the left anterior descending artery was performed.
On angiography, four connector grafts in 4 different patients were occluded. All connector occlusions were incidental findings in asymptomatic patients. One connector graft occluded at 6 postoperative days, and 3 grafts were occluded at 6-month follow-up. All the other connector grafts were widely patent at 6-month angiography (Fig 6). The patency was 88.9% (32 of 36).
Core Laboratory analysis showed freedom from greater than 50% stenoses of 97.1% (34 of 35) of connector grafts. One connector graft had a 51% stenosis immediately distal to the connector anastomosis. This lesion was considered hemodynamically insignificant at the time of angiography, and no intervention was performed. All grafts were TIMI flow grade 3. Mean CTFC was 19 ± 8 (range, 6 to 39). Mean TMPG was 2 ± 1 (range, 0 to 3). There was no flow limitation on patent connector grafts.
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Comment
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Manual suturing remains the gold standard for performing proximal anastomoses in coronary surgery. It is inexpensive and effective—but it is also dependent on surgical skills, is time consuming, requires clamping of the aorta, and is difficult to perform within the less-invasive approaches. By contrast, mechanical device anastomoses are quick, reproducible, easy to perform, less dependent on surgical skills, require no clamping of the aorta, and have the potential of facilitating less-invasive approaches [1, 2, 3–5]. The patency rate of these connector grafts has not been clarified.
The only device routinely used worldwide is the first-generation SJM symmetry aortic connector system for proximal vein graft-to-aorta anastomoses. Using this device, proximal anastomosis must be constructed first, a technique most surgeons are not familiar with [5]. Special care should be taken to estimate the proper length of the graft. Because of the 90-degree take-off angle, too long grafts increase the risk of kinking. Too short and overstretched grafts might predispose to occlusion [3]. During the loading process, the vein transfer sheath cannulates the whole graft, which may injure the intima [4, 5].
The second-generation aortic connector overcomes these disadvantages. The loading process is simpler and shorter but still implies a learning curve. The vein must be loaded in a proper way to create perfect anastomosis and avoid bleeding. The device enables us to construct either proximal or distal anastomosis first. The take-off for the connector graft is tangential to the aorta, thus minimizing the risk of kinking. The risk of kinking is still present in cases when the connector graft is placed low in the aorta, and the bulging right ventricle kinks the graft. In such cases, the first-generation connectors with a 90-degree take-off angle are more advantageous.
To choose the connector size, the internal diameter of the vein graft is measured. No graft cannulation is required, and no instrument passes through the part of the graft ultimately serving as the bypass conduit.
Our technical failures during the initial part of our study taught us some lessons to be aware of. First, the measurement of the vein graft internal diameter must be performed very carefully, and one has to avoid using smaller than indicated veins. The vein must not be tight around the sizing tool.
Then the process of the vein loading onto the delivery system must be extremely precise, and all the tiny hooks must perforate the vein close to the margin. If the hooks perforate too far away from the margin of the vein, it creates an indentation on the roof of the anastomosis after deployment. If the hooks perforate the vein just next to the margin or do not perforate the vein graft at all, there is a significant potential for leaking from the anastomosis. According to our experience, the distance of the small hooks from the margin of the vein should be between 0.2 and 0.5 mm.
We found that connectors are not suitable in cases where the aortic wall is more than 5 mm thick. We now use intraoperative ultrasound in case of concerns relative to aortic disease. We do not use the connector if the aortic wall is more than 4 mm thick or calcified.
In our initial experience, the 6-month angiographic results with the SJM second-generation connector show a satisfactory 6-month patency of 88.9%. This compares favorably with the historical patency rates for saphenous vein grafts performed with conventional hand-sewn technique [8, 9]. We did not find connector-related complications during our follow-up.
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Conclusion
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The SJM second-generation aortic connector is safe and easy to use. It retains the advantages of the first generation and offers more convenient handling with a smaller potential for technical failure. Preliminary results show no device-related complications and a 6-month angiographic patency comparable with that of historical controls. We are waiting for more data regarding the short- and long-term patency rates of connector grafts. We are currently participating in a prospective randomized study comparing connector grafts with the conventional suturing technique. This study will add to our understanding of the performance of this device as well as of the patency rates for the conventional suturing technique in a time when the patient population undergoing coronary artery bypass graft surgery is changing owing to an increase in catheter-based interventions.
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Disclosures and Freedom of Investigation
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This study was sponsored by St. Jude Medical, and the tested technology—the St. Jude Medical second-generation aortic connectors—were donated to the study. The authors confirm that they had full control of the design of the study, methods used, outcome parameters, analysis of data, and production of the written report.
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Disclaimer
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The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.
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References
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- Eckstein FS, Bonilla LF, 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(Suppl):S995-S998.[Abstract/Free Full Text]
- Eckstein FS, Bonilla LF, 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]
- Wiklund L, Bugge M, Berglin E. Angiographic results after the use of a sutureless aortic connector for proximal vein graft anastomoses Ann Thorac Surg 2002;73:1993-1994.[Abstract/Free Full Text]
- Antona C, Scrofani R, Lemma M, et al. Assessment of an aortosaphenous vein graft anastomotic device in coronary surgeryclinical experience and early angiographic results. Ann Thorac Surg 2002;74:2101-2105.[Abstract/Free Full Text]
- Mack MJ, Emery RW, Ley LR, et al. Initial experience with proximal anastomoses performed with a mechanical connector Ann Thorac Surg 2003;75:1866-1871.[Abstract/Free Full Text]
- Carrel TP, Eckstein FS, Englberger L, Windecker S, Meier B. Pitfalls and key lessons with the symmetry proximal anastomotic device in coronary artery bypass surgery Ann Thorac Surg 2003;75:1434-1436.[Abstract/Free Full Text]
- Protopapas AD. Anastomotic devices for coronary bypasslethal complications have been previously reported!. Eur J Cardiothorac Surg 2004;25:145.[Free Full Text]
- FitzGibbon GM, Kafka HP, Leach AJ, Keon WJ, Hooper GD, Burton JR. Coronary bypass graft fate and patient outcomeangiographic follow up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years. J Am Coll Cardiol 1996;28:616-626.[Abstract]
- Goldman S, Copeland J, Moritz T, et al. Internal mammary artery and saphenous vein graft patencyeffects of aspirin. Circulation 1990;82(Suppl 4):237-242.
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Abstract
Introduction
