Ann Thorac Surg 2009;88:258-261. doi:10.1016/j.athoracsur.2009.02.046
© 2009 The Society of Thoracic Surgeons
New Technology
An Experimental Study of Type I Endoleak Repair With a Suturing Device
Hiroshi Ohtake, MDa,*,
Shigeyuki Tomita, MDa,
Shoujirou Yamaguchi, MDa,
Shuhei Yoshida, MDa,
Keiichi Kimura, MDa,
Junichirou Sanada, MDb,
Osamu Matsui, MDb,
Go Watanabe, MDa
a Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan
b Department of Radiology, Kanazawa University, Kanazawa, Japan
Accepted for publication February 16, 2009.
* Address correspondence to Dr Ohtake, Department of General and Cardiothoracic Surgery, Kanazawa University, Takara-machi 13-1, Kanazawa, 920-8641, Japan (Email: ohtake{at}med.kanazawa-u.ac.jp).
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Abstract
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Purpose: An experimental study was done to investigate repair of type I endoleaks in thoracic aortic aneurysms using the T-Fix suturing device (Smith & Nephew Co, Ltd, London, United Kingdom).
Description: A saccular descending aortic aneurysm was made in 5 pigs experimentally. A stent graft was deployed to produce a proximal type I endoleak. Under fluoroscopy, the aorta was punctured with the spinal needle with the T-Fix plastic bar, and the plastic bar was deployed with a push rod. A sufficient number of T-Fix sutures were used until angiography revealed that the type I endoleak had disappeared.
Evaluation: No hemodynamic events occurred during the procedure. An average of 2.5 ± 0.6 T-Fix sutures were required to eliminate the endoleak. The experimental T-Fix repair was performed without any complications. A new method of repairing type I endoleaks for thoracic aortic aneurysms was successfully performed using the T-Fix system.
Conclusions: Although the T-Fix repair currently has some anatomic and clinical limitations, improvement of the device should lead to the increased use of this repair.
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Introduction
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Stent grafting has arguably become the first choice of treatment for thoracic aortic aneurysm (TAA) and descending aortic aneurysm, in particular [1, 2]. With proximal descending aorta or distal aortic arch aneurysms, however, an adequate landing zone cannot be ensured because of supraaortic arteries, and type I endoleaks readily occur due to the curvature of the aorta [3]. The reported incidence of perioperative type I endoleaks is 8% to 29% [2, 4]. Such endoleaks are the most frequent complication associated with stent grafting and have been treated by additional stent grafting, an endovascular approach, and other methods. The current research experimentally studied a new method of repairing type I endoleaks.
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Technology
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Animal Preparation
Five pigs weighing between 30 and 40 kg were treated according to the "Guidelines for the Care and Use of Laboratory Animals" at the Takara-machi Campus of Kanazawa University.
The procedure was performed under general anesthesia with endotracheal intubation. Anesthesia was maintained with 40% nitric oxide and sevoflurane. Electrocardiography, heart rate, continuous blood pressure, and blood gases were monitored. Ringer's lactate solution was administered for hydration.
The animals were placed in the right lateral position. The descending aorta was exposed through an incision at the third or fourth posterolateral intercostal space. Heparin (50 U/kg) was administered intravenously. The descending aorta was clamped and incised longitudinally. A Dacron (DuPont, Wilmington, DE) graft (Hemashield Gold; Boston Scientific Co, Ltd, Natick, MA), 14 mm in diameter and 2 cm long, with one end closed, was anastomosed end-to-side using 5-0 nonabsorbable Prolene suture (Ethicon Inc, Somerville, NJ), thus serving as a model of saccular aneurysm (Fig 1a). An angiographic catheter (SZ4123; Medikit Co, Ltd, Tokyo, Japan) was placed in the ascending aorta through the right carotid artery to obtain aortograms.
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Fig 1. In this saccular aneurysm model endoleak repair, (a) a saccular aneurysm (arrow) was created by a Dacron graft end-to-side to the descending. (b) The preoperative angiographic findings showed a type I endoleak (arrow).
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Stent Graft System and Deployment
The study used self-expandable curved Matsui-Kitamura (M-K) stent grafts (Cathex, Kanazawa, Japan) measuring 20 mm in diameter and 40 mm in length. This M-K stent graft has been previously described in detail [1]. This stent graft was deployed through an 8F guiding sheath (Shuttle Select System; Cook, Bloomington, IN) with a push rod.
After a small laparotomy, the abdominal aorta was punctured and an 8F sheath (Supersheath; Medikit Co Ltd, Tokyo, Japan) was inserted. Under fluoroscopy (OEC 9800; GE Healthcare Co Ltd, Waukesha, WI) the stent graft was advanced through the sheath with a stent pusher. The stent graft was deployed to produce a proximal type I endoleak (Fig 1b).
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Technique
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Suturing Device and Endoleak Repair
The T-Fix system (Smith & Nephew Co, Ltd, London, UK) is an all-inside endoscopic meniscal repair device and is commercially available [5, 6]. This suturing device consists of a 2-holed small plastic (polyacetal) bar, through which 2-0 nonabsorbable polyester sutures are passed. It is transported inside a spinal needle. The needle is inserted, and the plastic bar of the T-Fix is deployed with a push rod (Fig 2). The plastic bar is anchored in place by tying several T-Fix sutures together, providing fixation to the tissue [5, 6]. Figure 3
shows a simulation of this method. To close the gap between the tube and the graft, the first T-Fix was inserted into the lumen through both the tube and the graft (Fig 3a). The plastic bar was anchored (Fig 3,), and a second T-Fix was inserted. Finally, 2 sutures were tied, and the gap was closed (Fig 3c).
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Fig 2. The T-Fix system (Smith & Nephew Co, Ltd, London, United Kingdom) consists of (a) a 2-holed small plastic (polyacetal) bar, through which 2-0 nonabsorbable polyester suture is passed, is transported inside a spinal needle. (b) The needle is inserted, and the T-Fix plastic bar is deployed with a push rod. The plastic bar is anchored.
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Fig 3. This simulation shows (a) the first T-Fix (Smith & Nephew Co, Ltd, London, United Kingdom) being inserted into the lumen through both the tube and the graft, (b) the plastic bar is anchored, and (c) two sutures are tied after the second T-Fix was inserted.
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In this study, a thoracotomy had already been performed, so a spinal needle was inserted into the thoracic cavity directly. Under fluoroscopy, the aorta was punctured with the spinal needle and the T-Fix was deployed with a push rod. The T-Fix plastic bar was anchored, several T-Fix sutures were tied, and the stent graft was attached to the aorta (Fig 4a). A sufficient number of T-Fix sutures were used until angiography revealed that the type I endoleak had disappeared (Fig 4b).
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Fig 4. Endoleak repair. (a) T-Fix (Smith & Nephew Co, Ltd, London, United Kingdom) repair was performed (arrow 1 shows sutures of the first T-Fix, arrow 2 shows the second T-Fix needle). (b) Post-operative angiographic findings showed that the endoleak had disappeared.
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After postoperative angiography, the pigs were euthanized and the portion of the aorta containing the stent was harvested.
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Clinical Experience
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The present study is not a clinical investigation. The data was obtained by the animal experiment.
The procedure was successfully completed in 5 pigs according to the established protocol. No hemodynamic events occurred during the procedure. An average of 2.5 ± 0.6 T-Fix sutures were required to eliminate the endoleak. Visual inspection indicated that harvested aortic segments containing stent grafts had no significant changes. No bleeding occurred during aortic puncture in any of the animals. A pathologic evaluation noted precise attachment of the T-Fix penetrating the stent graft and aortic wall.
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Comment
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Stent grafting is a minimally invasive treatment for TAA and has been beneficial for many patients in whom conventional graft replacement would be difficult. Improved long-term results for descending TAA repair, in particular, have been obtained [7]. For distal aortic arch aneurysms, a relatively high 8% to 29% incidence of perioperative type I endoleaks is reported, although debranching of supraaortic arteries is performed to ensure a sufficient proximal landing zone and avoid proximal type I endoleaks [2, 4, 8]. These endoleaks will cause TAAs to rupture; thus, developing methods to repair these endoleaks is crucial.
Approaches such as additional stent grafting or coiling have been attempted for type I endoleaks [2, 9], but conversion to surgical graft replacement is eventually required [2, 8, 9]. A conventional surgical procedure is invasive for many patients, however, and there are also often hesitations to perform this operation.
Custom-made stent grafts designed to ensure an adequate landing zone include branched and fenestrated stent grafts; these types of stent graft have been discussed and used clinically [10]. Sparse data are available on the clinical use of commercially available branched and fenestrated stent grafts. The accidental obstruction of brachiocephalic or left carotid arteries is fatal. Additional endovascular repairs have failed to demonstrate satisfactory results.
The present study showed that the T-Fix system can be used to repair proximal type I endoleaks after stent graft treatment for TAA. Precise puncturing of the aorta with the needle transporting the T-Fix was performed safely. Intraoperative angiography helped with the insertion of additional T-Fix sutures. Results of this experiment indicated that from 2 to 4 T-Fix sutures were able to stop endoleaks.
In this experiment, a normal porcine aorta was punctured, and fixation of a stent graft to the aorta using T-Fix sutures was performed safely, with no complications. In patients with an aortic aneurysm, however, arteries are typically in poor condition, and there is a risk of complications such as bleeding, localized dissection, and embolism in peripheral vessels when a diseased (and particularly a calcified) aorta is punctured. In clinical practice, vital steps would thus be to observe the state of the aorta with intravascular ultrasound and perform the procedure under fluoroscopy.
There are anatomic limitations to this T-Fix repair. In this study, proximal type I endoleaks of experimental saccular aneurysms were repaired. In terms of the shape of the aneurysm, repair of saccular aneurysms should prove easier than repair of fusiform aneurysms. Clinically, there are cases of a TAA in which aortic puncture will be anatomically difficult, the aorta is severely atherosclerotic, or pleural adhesions are present. Development of a more flexible and smaller diameter needle is expected. In some cases, the endoleaks are not revealed by angiography but by computed tomography. This pinpoint repair using the T-Fix might prove difficult in such cases.
Ensuring an adequate landing zone is vital to preventing endoleaks. Of course, a relatively small type I endoleak may disappear over time, so this method would not be performed at the same time as the initial endovascular therapy. In addition, a running suture is also an effective surgical procedure to repair an endoleak. Despite several clinical limitations, the T-Fix repair should prove effective for type I endoleaks in high-risk patients and in instances of a short landing zone. Although this study involved a thoracotomy, a less invasive thoracoscopic approach could be used clinically.
In conclusion, a new method of repairing type I TAA endoleaks with the T-Fix system was experimentally tested. The experimental T-Fix repair was performed without any complications. Although the T-Fix repair currently has some anatomic and clinical limitations, improvement of the device should lead to the increased use of this repair.
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Disclosures and Freedom of Investigation
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All authors have no commercial association or sources of support that may pose a conflict of interest. In addition, the authors had full control of the study, methods used, outcome measurements, data analysis, and preparation of the article. None of the authors has received any financial compensation for this publication.
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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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- Ohtake H, Kimura K, Watanabe G, et al. Clinical application of an original flexible MK stent-graft for nonruptured thoracic aortic aneurysms: early experience Innovations 2006;1:119-122.
- Czerny M, Grimm M, Zimpfer D, et al. Results after endovascular stent graft placement in atherosclerotic aneurysms involving the descending aorta Ann Thorac Surg 2007;83:450-455.[Abstract/Free Full Text]
- Morales JP, Greenberg RK, Lu Q, et al. Endoleaks following endovascular repair of thoracic aortic aneurysm: etiology and outcomes J Endovasc Ther 2008;15:631-638.[Medline]
- Chu M, Forbes T, Lawlor K, Harris K, Derose G. Endovascular repair of thoracic aortic disease: early and midterm experience Vasc Endovasc Surg 2007;41:186-191.
- Asik M, Sen C, Erginsu M. Arthroscopic meniscal repair using T-fix Knee Surg Sports Traumatol Arthrosc 2002;10:284-288.[Medline]
- Haas AL, Schepsis AA, Hornstein J, Edgar CM. Meniscal repair using the FasT-Fix all-inside meniscal repair device Arthroscopy 2005;21:167-175.[Medline]
- Makaroun MS, Dillavou ED, Kee ST, et al. Endovascular treatment of thoracic aneurysms: results of the phase II multicenter trial of the GORE TAG thoracic endoprosthesis J Vasc Surg 2005;41:1-9.[Medline]
- Czerny M, Gottardi R, Zimpfer D, et al. Mid-term results of supraaortic transpositions for extended endovascular repair of aortic arch pathologies Eur J Cardiothorac Surg 2007;31:623-627.[Abstract/Free Full Text]
- Nienaber CA, Kische S, Ince H. Thoracic aortic stent-graft devices: problems, failure modes, and applicability Semin Vasc Surg 2007;20:81-89.[Medline]
- Inoue K, Hosokawa H, Iwase T, et al. Aortic arch reconstruction by transluminally placed endovascular branched stent graft Circulation 1999;100(19 suppl):II316-II321.[Medline]
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Abstract
Introduction
