Ann Thorac Surg 2006;82:303-306
© 2006 The Society of Thoracic Surgeons
New technology
Experimental Study of One-Shot Vascular Anastomostic Device for Proximal Vein Graft Anastomoses
Luqi Liu, MD, PhD
*
,
Junsheng Liu, MD,
Meijia Zhu, MD,
Shouxiang Hu, MD
Cardiac Department of Shandong Provincial Qianfoshan Hospital, Shandong University, Shandong Province, China
Accepted for publication January 24, 2006.
* Address correspondence to Dr Luqi Liu, Shandong Provincial Qianfoshan Hospital, 66 Jingshi Rd, Jinan, Shandong Province, 250014 China (Email: luqizh{at}public.jn.sd.cn).
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Abstract
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PURPOSE: A new type of sutureless aortic-vein-graft vascular anastomostic device, One-Shot Vascular Anastomostic Device (Horologe Factory of Jinan City, Shandong Province, China) has been recently designed to create a one-shot anastomosis between the aorta and vein grafts for coronary artery bypass grafting surgery.
DESCRIPTION: Twelve pigs were scheduled for the test of the feasibility of the One-Shot Vascular Anastomostic Device for artery to vein graft anastomosis. In each animal one proximal anastomosis was performed by means of the One-Shot Vascular Anastomostic Device and the distal end was sutured in a conventional manner to serve as the animal own control. The anastomosis incorporating the abdominal main artery to the segment of a free external carotid vein to the external iliac artery is for the simulation of the aorta-vein anastomosis.
EVALUATION: The mean duration of the completion of the proximal anastomosis was 1.2 ± 1.2 minutes (range, 0.3–5.0 minutes). There was a significant difference between the control groups (p < 0.01). All vein grafts were still functioning at the end of the procedure. Pathologic studies and angiography demonstrated that the results were satisfactory.
CONCLUSIONS: This device enables rapid and safe completion of vascular anastomostic procedure. The vein graft was functioning well and incorporated into the vessel intima smoothly.
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Introduction
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The coronary artery bypass grafting has recently generated a need to shorten the operating time as much as possible. Using semiautomated techniques to create vascular anastomosis is currently being studied but needs to be perfected. A new type of mechanical device for facilitating vascular anastomosis was designed by us and enables a rapid, nonpenetrated, and compliant proximal vascular reconstruction. This report is to deal with the experimental results.
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Technology
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The One-Shot Vascular Anastomostic Device (OVAD) designed by Luqi Liu with the help of a professional technician was made in the Horologe Factory of Jinan City, Shandong Province (Chinese Patent No.: ZL200420052936.0). The OVAD consists of a round handle and a pliers-like cartridge. The cartridge is a detachable unit that is pre-loaded with six square staples (Fig 1) and combined with a device handle. It is activated by one squeeze on the device handle. Before the anastomosis is conducted, the external jugular vein graft was harvested. The external diameter of the graft was assessed to match with the best-fitting size of the cartridge previously mentioned. Then the vein graft is pulled through the central hole of the device. The end of the vein graft was everted over the near-the-axis staple tips housed in the cartridge (Fig 2). Eversion of the vein graft over the staple tips maintains positioning; it then guides the cartridge that is holding the everted end of the vein graft into the aortic neo-ostium, which is made on the wall of the aorta with a punch by removing a circular piece of tissue. The staples were released by squeezing the device so that the entire anastomosis circumference is formed simultaneously. The result of an intima-to-intima anastomotic configuration is then attained. The diameter of the aortic neo-ostium varies from 3.5 to 5.5 mm. It should be emphasized that the rim of the neo-ostium in the recipient aorta should be pressed against the already everted donor vein graft, with the other row of the exposed staple tips. The shape of the staples assures that the staples will stay in the desired locations, which is effective to stop the bleeding. After the staples are released simultaneously, the cartridge is withdrawn with the other parts of the device from the anastomosis procedure (Fig 3). The cartridges of OVAD are made with different calibers (sizes) to fit vein grafts of 4 to 10 mm in the outer diameter.
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Fig 1. (A) Inset: Shape of the clips from different directions. (B) Circumferentially pre-loaded, disposable oval cartridge containing six staples. Photograph made by 3D-MAX.
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Fig 2. (A) Vessel is pulled through the inner lumen of the transfer sheath. (B) Inset: The end of vein graft was everted over the distal clip tips housed in the cartridge.
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Fig 3. (A) The rim of the opening in the recipient aorta maintains closed to the already everted vein graft held in place by the exposed clip tips. (B) The cartridge is withdrawn with the other parts of the device from the anastomosis construct.
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Technique
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Animal experiments consisted of extensive laboratory testing of the OVAD that have been conducted at the Experimental Animal Center of the Qianfoshan Provincial Hospital, Shandong University. All animals were treated within the guidelines of "Standards for the Care and Use of Laboratory Animals of P. R. China" (GB/T 14926.13-2001) published by the Ministry of Science and Technology of P. R. China. Humane care was provided in accordance with these guidelines. There were no ethic problems in the experiments with any of the selected animals. Twelve pigs were selected for experimental use. The average body weight was 26.92 ± 3.4 kg (range, 21–32 kg). Anesthesia was induced by intramuscular injection of ketamine (10 mg/kg) and intravenous injections of thiopental sodium (4 mg/kg), atropine (1 mg), and antibiotic penicillin (4,000, 000 IU). Midazolam (0.3 mg/kg/h) and propranolol (range, 10–25 mg) was administered intravenously as necessary. Analgesia was obtained by fentanil (1 ug/kg/h). After anesthesia was done, a segment of the jugular vein was harvested from the same experimental pig. The diameters of the 12 vein grafts for testing the OVAD were 5.0 ± 1.21 mm (range, 4–8 mm). Next the inferior abdominal paramediam incision was made to expose the great vessels beneath the peritoneum. All the surgeries of anastomosis, by means of the OVAD, were performed by clamping of the arteries. After proximal anastomosis was completed with the OVAD, the distal end anastomosis was performed by a hand suture in the conventional manner as a control group.
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Clinical Experience
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Mean time for loading the vein grafts to the device was 13.17 ± 2.29 minutes (range, 9–17 minutes). The loading can be done without hurrying because it is done prior to clamping the artery and performing anastomosis. The final step of the anastomostic procedure can be performed as one shot, and it is much faster than doing a hand suture. Thus the overall time for anastomosis is greatly shortened. It takes time to evert the edge of the vein graft on the device with the help of forceps and to make certain that the length of the eversion edge of the vein graft is sufficient and uniform. If the process of loading the vein graft is too rough, the clips stuck in the slot by its own elasticity may spring out of the slot on the device by accident. Then the vein graft will detach from the device prior to the fixation of the aorta and what is needed next is to simply repeat the loading step again.
The OVAD has successfully created a bridge vein graft between the abdominal main artery and the iliac artery. The duration of completing each mechanical anastomosis was 1.2 ± 1.2 minutes (range, 0.3–5 minutes). The time used for distal anastomosis was 10.92 ± 1.78 minutes (8–14 minutes). The proximal anastomosis was perfect in 9 of the 12 animals. There were three system failures, in which 1 to 3 stitches of hand sutures were needed for hemostasis. All distal anastomoses were done without bleeding. All vein grafts were functioning at the end of the procedure. Intraoperative graft blood flow measured with a transit Doppler flow meter that was assessed in all of the studied grafts. The flow measurements ranged from 68 to 97 mL/min (mean, 82.25 ± 7.83 mL/min).
Two months after the surgery, the angiography was conducted in all animals and tissues that were taken from the anastomostic orifice were examined by an optical microscope and a scan electronic microscope. Angiography results indicated that 11 device anastomoses were fully functioning without obvious diameter narrowing and one with slight narrowing caused by two stitches that were conducted for hemostasis. Histologic analysis showed that complete vessel wall intima-intima apposition was established along the full circumference (Fig 4). The intima-intima linings were well recognized by the electric microscopic scanning (Fig 5). No excessive lumen-narrowing intimal hyperplasia was found in any of the device anastomoses after 2 months. No medial necrosis or thinning of either arteries or grafts was observed between the clips. At postoperative week 8 an adhesion was found around the outside of each of the anastomostic orifice. Media thickness was seen in all vein grafts. The reactions of inflammatory cells were observed in the wall around the anastomosis and clips. The studies showed that the OVAD anastomostic procedures were histologic and functionally equivalent with the manual suture procedures in the control group.
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Fig 4. The specimens were taken 2 months after the device anastomosis. (A) The intima-intima apposition was established along the full circumference of the anastomosis orifice. (B) Inset: Transaction of the anastomosis orifice. Broken clips (arrow) were shown in the outer area of the intimae.
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Fig 5. The intima-intima linings were well recognized by electric microscopic scanning (x100 magnification).
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Data was presented as mean ± standard deviation. The t test was used to compare the means between the two groups by means of the SPSS 10.0 software package (SPSS Inc, Chicago, IL).
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Comment
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Manual suturing is the common technique for the creation of vascular anastomoses. Because the quality of suture materials has improved considerably in the last decades, the manual suture is believed to be a cheap, simple, and effective method [1]. However the challenge to mechanize and thus facilitate and improve the quality of vascular reconstructions has been reactivated by some surgical interventions. Reliable vascular reconstruction devices are particularly warranted in the field of minimally invasive cardiothoracic surgery, in which the capability of performing an end-to-side anastomosis in a restricted field is critical. Previous attempts, including penetrating staples [2, 3], nonpenetrating clips [4–7], and tissue adhesives [8, 9] have mostly focused on connectors allowing anstomosis of vein-to-coronary, lima-to-coronary, and aorta-to-saphenous. Our device is a great time-saver for the surgical anastomosis, finishing the anastomosis in one shot. The use of special designed square staples allows a firm connection and uniform distances between the staples, which is effective for hemostasis. It achieves an intima-to-intima anastomosis without staples penetrating the blood and damaging the endothelium.
It is known that the Symmetry Connector System (St. Jude Medical, St. Paul, MN) [1], the Corlink Device-ADD (ByPass Ltd, Herzelia, Israel) [2], the One-Shot Connector (St. Jude Medical, St. Paul, MN), and the Heartflo-Perclose (Abbott Labs Inc, Abbott Park, IL) [3, 7] are all mechanical semiautomatic devices. The Symmetry device has the disadvantage of stenosis and poor patency rates at 6 months and beyond after it is put to use. We do not have any clinical experience using our device and long-term histologic results to compare with their results. The anastomosis stenosis in cases of using the Symmetry Connector System may mainly be caused by intimae hyperplasia and nonductility of the anastomostic clip ring (Fig 6). The differences between the Symmetry device and ours are the designs of the clips and the efficiency of the clip releasing. Our square clips have resolved many problems such as unstable loading, undesired distances among the staples, and bleeding. An intima-to-intima anastomosis derives from no clip penetrating to the blood and damaging the endothelium, which is very important in avoiding intimae hyperplasia and re-stenosis of anastomosis (Fig 4). In addition, a group of detached staples gives an interrupted connection, which leaves the anastomostic orifice extendable in the process of tissue healing. Besides, the device is detachable, reusable, and can be sterilized easily. The results of using the OVAD have demonstrated a satisfied graft patency. It is as good as the results of using conventionally sutured anastomoses. However there are technical aspects of this new device that deserve attention. The loading procedure has a learning curve in terms of time consumption and technique. The shortcoming of the device is that the proximal anastomosis has to be finished first and leaves the distal vein graft end free. Otherwise, this device can not be detached from the vein graft. Special care should be taken to match the diameter of the orifice made in the aorta with the diameter of the vein graft.
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Fig 6. Intraoperative inside view of proximal vein anastomosis with the Symmetry Anastomostic connector. (Reprinted from J Thorac Cardiovasc Surg, 124, Eckstein FS et al, The St. Jude Medical symmetry aortic connector system for proximal vein graft anastomoses in coronary artery bypass grafting, 777–82, Copyright 2002, with permission from Elsevier [1].)
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In conclusion, the use of the sutureless one-shot anastomosis device for proximal anastomosis has shown a satisfactory early graft patency. However there are surgical and technical aspects that merit attention.
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Disclosures and Freedom of Investigation
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The funds used to perform the evaluation were provided by Shandong Health Department and Qianfoshan Hospital. The tested technology was developed by the authors themselves. The authors have performed an independent assessment and had full control of the study design, method, experimental study, outcome measurements, analysis of data, and production of the written report.
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Acknowledgments
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Thanks to Hongrong Lu and his colleagues for their help in producing the devices based on Dr Luqi Liu's designation.
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Footnotes
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Disclaimer 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. 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]
- Riess FC, Helmold H, Hilfer I, et al. Clinical experience with the CorLink Device for proximal anastomosis of the saphenous vein to the aortaa clinical, prospective, and randomized study. Heart Surg Forum 2002;5(4):345-353.[Medline]
- Nataf P, Kirsch W, Hill AC, et al. Nonpenetrating clips for coronary anastomosis Ann Thorac Surg 1997;63:S135-S137.[Medline]
- Schaff HV, Zehr KJ, Bonilla LF, et al. An experimental model of saphenous vein-to-coronary artery anastomosis with the St. Jude medical stainless steel connector Ann Thorac Surg 2002;73:830-836.[Abstract/Free Full Text]
- Eckstein FS, Bonilla LF, Schaff H, et al. Two generations of the St. Jude Medical ATG Coronary Connector Systems for coronary artery anastomoses in coronary artery bypass grafting Ann Thorac Surg 2002;74:S1363-S1367.[Abstract/Free Full Text]
- Hill AC, Maroney TP, Virmani R, et al. Facilitated coronary anastomosis using a nitinol U-clip devicebovine model. J Thorac Cardiovasc Surg 2001;121:859-870.[Abstract/Free Full Text]
- Tozzia P, Hayozb B, Ruchata P, et al. Animal model to compare the effects of suture technique on cross-sectional compliance on end-to-side anastomoses Eur J Cardiothorac Surg 2001;19:477-481.[Abstract/Free Full Text]
- Gundry SR, Black K, Izutani H. Sutureless coronary artery bypass with biologic glued anastomosespreliminary in vivo and vitro results. J Thorac Cardiovasc Surg 2000;120:474-477.
- Buijsrogge MP, Scheltes JS, Heikens MM, et al. Sutureless coronary anastomosis with an anastomotic device and tissue adhesive in off-pump porcine coronary bypass grafting J Thorac Cardiovasc Surg 2002;123:789-794.
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Abstract
Introduction
