Abstract
Stent graft endoleak is a major problem in endovascular aneurysm repair (EVAR). Endoleak occurs after EVAR and may lead to aneurysm rupture, acute vessel thrombosis or occlusion. This study presents a novel design to potentially reduce endoleak with use of magnets. A ferromagnetic stent is deployed into the vessel lumen, and two external flexible magnetic rings are used to clamp on the proximal and distal necks of the stent. The rings impose epivascular magnetic pressure on the vessel wall to prevent the vessel wall from separating from the stent under elevated blood pressure. The geometry and magnetic properties of the stent and rings were designed to produce sufficient pressure, without overly compressing the vessel wall. Feasibility of this design was demonstrated with in vitro experiments using porcine abdominal aortas. The experiments showed that magnetic ring significantly improved the seal between the stent and vessel wall with use of moderate-sized stent. For aortas subjected to physiological axial stretch, rings that generate magnetic pressure of about 45 mmHg were found sufficient to prevent endoleak at pressure of 140 mmHg. Evaluation of this design in an in vivo animal model of aortic aneurysm is warranted.
Similar content being viewed by others
References
Beebe, H. G., J. L. Cronenwett, B. T. Katzen, D. C. Brewster, and R. M. Green. Results of an aortic endograft trial: impact of device failure beyond 12 months. J. Vasc. Surg. 33:S55–S63, 2001. doi:10.1067/mva.2001.111663.
Blum, U., G. Voshage, J. Lammer, F. Beyersdorf, D. Töllner, G. Kretschmer, G. Spillner, P. Polterauer, G. Nagel, and T. Hölzenbein. Endoluminal stent-grafts for infrarenal abdominal aortic aneurysms. N. Engl. J. Med. 336:13–20, 1997. doi:10.1056/NEJM199701023360103.
Chaikof, E. L., J. D. Blankensteijn, P. L. Harris, G. H. White, C. K. Zarins, V. M. Bernhard, J. S. Matsumura, J. May, F. J. Veith, M. F. Fillinger, R. B. Rutherford, and K. C. Kent. Ad hoc committee for standardized reporting practices in vascular surgery of the society for vascular surgery/American association for vascular surgery. Reporting standard for endovascular aortic aneurysm repair. J. Vasc. Surg. 35:1048–1060, 2002. doi:10.1067/mva.2002.123763.
Erdmann, D., R. Sweis, C. Heitmann, K. Yasui, K. C. Olbrich, L. S. Levin, A. A. Sharkawy, and B. Klitzman. Side-to-side sutureless vascular anastomosis with magnets. J. Vasc. Surg. 40:505–511, 2004. doi:10.1016/j.jvs.2004.05.026.
Falk, V., T. Walther, H. Stein, S. Jacobs, C. Walther, A. Rastan, G. Wimmer-Greinecher, and F. W. Mohr. Facilitated endoscopic beating heart coronary artery bypass grafting using a magnetic coupling device. J. Thorac. Cardiovasc. Surg. 126:1575–1579, 2003. doi:10.1016/S0022-5223(03)00793-1.
Finn, R. Consider pulsatility when sizing aortic endografts. Thorac. Surg. News 3(4):10, 2007.
Freud, L. B. Dynamic Fracture Mechanics. Cambridge University Press, 1990.
Fung, Y. C., K. Fronek, and P. Patitucci. Pseudoelasticity of arteries and the choice of its mathematical expression. Am. J. Physiol. 237:H620–H631, 1979.
Garasic, J. M., E. R. Edelman, J. C. Squire, P. Seifert, M. S. Williams, and C. Rogers. Stent and artery geometry determine intimal thickening independent of arterial injury. Circulation 101:812–818, 2000.
Golzarian, J., and D. Valenti. Endoleakage after endovascular treatment of abdominal aortic aneurysms: diagnosis, significance and treatment. Eur. Radiol. 16:2849–2857, 2006. doi:10.1007/s00330-005-0129-6.
Gurrappa, I., and S. Pandian. Corrosion characteristics of Nd-Fe-B permanent magnets in different environments. Corros. Eng. Sci. Technol. 41:57–61, 2006.
Heikkinen, M. A., J. M. Alsac, F. R. Arko, R. Metsänoja, A. Zvaigzne, and C. K. Zarins. The importance of iliac fixation in prevention of stent graft migration. J. Vasc. Surg. 43:1130–1137, 2006. doi:10.1016/j.jvs.2006.01.031.
Hinchliffe, R. J., and B. R. Hopkinson. Endovascular repair of abdominal aortic aneurysm: current status. J. R. Coll. Surg. Edinb. 47:523–527, 2002.
Jiles, D. C. Introduction to Magnetism and Magnetic Materials, 2nd edn. Chapman & Hall/CRC, 1998.
Kassab, G. S., and J. A. Navia. Biomechanical considerations in the design of graft: the homeostasis hypothesis. Annu. Rev. Biomed. Eng. 8:499–535, 2006. doi:10.1146/annurev.bioeng.8.010506.105023.
Kinloch, A. J., C. C. Lau, and J. G. Williams. The peeling of flexible laminates. Int. J. Fracture 66:45–70, 1994. doi:10.1007/BF00012635.
Klima, U., V. Falk, M. Maringka, S. Bargenda, S. Badack, A. Moritz, F. Mohr, A. Haverich, and G. Wimmer-Greinecker. Magnetic vascular coupling or distal anastomosis in coronary artery bypass grafting: a multi-center trial. J. Thorac. Cardiovasc. Surg. 126:1568–1574, 2003. doi:10.1016/S0022-5223(03)01314-X.
Lambert, A. W., D. J. Williams, J. S. Budd, and M. Horrocks. Experimental assessment of proximal stent-graft (intervasculartm) fixation in human cadaveric infrarenal aortas. Eur. J. Vasc. Endovasc. Surg. 17:60–65, 1999. doi:10.1053/ejvs.1998.0711.
Litwinski, R. A., C. E. Donayre, S. L. Chow, T. K. Song, G. Kopchok, I. Walot, and R. A. White. The role of aortic neck dilation and elongation in the etiology of stent graft migration after endovascular abdominal aortic aneurysm repair with a passive fixation device. J. Vasc. Surg. 44:1176–1181, 2006. doi:10.1016/j.jvs.2006.08.028.
Liu, Y., C. Dang, M. Garcia, H. Gregersen, and G. S. Kassab. The surrounding tissues significantly affect the mechanics of the vessel wall: theory and experiment. Am. J. Physiol. Heart Circ. Physiol. 293:H3290–H3300, 2007. doi:10.1152/ajpheart.00666.2007.
Liu, Y., W. Zhang, and G. S. Kassab. Effects of myocardial constraint on the passive mechanical behaviors of the coronary vessel wall. Am. J. Physiol. Heart Circ. Physiol. 294:H514–H523, 2008. doi:10.1152/ajpheart.00670.2007.
Liu, Z. P., Y. Huo, J. A. Navia, and G. S. Kassab. A magnetic device to eliminate endograft migration: theory and experiment. Annu. Biomed. Eng. 36:57–65, 2008. doi:10.1007/s10439-007-9404-9.
Makaroun, M. S., E. Chaikoff, T. Naslund, and J. S. Matsumura. Efficacy of a bifurcated endograft versus open repair of abdominal aortic aneurysms: a reappraisal. J. Vasc. Surg. 35:203–210, 2002. doi:10.1067/mva.2002.120377.
Marrewijk, C., J. M. Buth, P. L. Harris, L. Norgren, A. Nevelsteen, and M. G. Wyatt. Significance of endoleaks after endovascular repair of abdominal aortic aneurysms: The EUROSTAR experience. J. Vasc. Surg. 35:661–673, 2002. doi:10.1067/mva.2002.121755.
Mohan, I. V., R. J. Laheij, and P. L. Harris. Risk factors for endoleak and the evidence for stent-graft oversizing in patients undergoing endovascular aneurysm repair. Eur. J. Vasc. Endovasc. Surg. 21:344–349, 2001. doi:10.1053/ejvs.2000.1341.
Moore, W. S., D. C. Brewster, and V. M. Bernhard. Aorto-uni-iliac endograft for complex aortoiliac aneurysms compared to the tube/bifurcation endografts. J. Vasc. Surg. 33:511–520, 2001. doi:10.1067/mva.2001.111681.
Onitsuka, S., A. Tanaka, H. Akashi, K. Akaiwa, H. Otsuka, H. Yokokura, and S. Aoyagi. Initial and midterm results for repair of aortic diseases with handmade stent grafts. Circ. J. 70:726–732, 2006. doi:10.1253/circj.70.726.
Peterson, B. G., G. M. Longo, J. S. Matsumura, M. R. Kibbe, M. D. Morasch, K. R. Cardeira, and M. K. Eskandari. Endovascular repair of thoracic aortic pathology with custom-made devices. Surgery 138:598–605, 2005. doi:10.1016/j.surg.2005.06.043.
Qu, J., and J. L. Bassani. Finite cracks on bimaterial and bicrystal interfaces. J. Mech. Phys. Solids 37:435–453, 1989. doi:10.1016/0022-5096(89)90022-7.
Rogachefsky, R. A., R. D. Altman, M. S. Markov, and H. S. Cheung. Use of a permanent magnetic field to inhibit the development of canine osteoarthritis. Bioelectromagnetics 25:260–270, 2004. doi:10.1002/bem.10192.
Sampaio, S. M., J. M. Panneton, G. I. Mozes, J. C. Andrews, T. C. Bower, M. Karla, A. A. Noel, K. J. Cherry, T. Sullivan, and P. Gloviczki. Proximal type i endoleak after endovascular abdominal aortic aneurysm repair: predictive factors. Ann. Vasc. Surg. 18:621–628, 2004. doi:10.1007/s10016-004-0100-z.
Scott, S., G. G. Ferguson, and M. R. Roach. Comparison of the elastic properties of human intracranial arteries and aneurysms. Can. J. Physiol. Pharmacol. 50:328–332, 1972.
Van Prehn, J., K. L. Vincken, B. E. Muhs, G. K. W. Barwegen, L. W. Bartels, M. Prokop, F. L. Moll, and H. J. M. Verhagen. Toward endografting of the ascending aorta: insight into dynamics using dynamic cine-CTA. J. Endovasc. Therapy 14:551–560, 2007. doi:10.1583/1545-1550(2007)14[551:TEOTAA]2.0.CO;2.
Wain, R. A., M. L. Marin, T. Ohki, L. A. Sanchez, R. T. Lyon, A. Rozenblit, W. D. Suggs, J. G. Yuan, and F. J. Veith. Endoleaks after endovascular graft treatment of aortic aneurysms: classification, risk factors, and outcome. J. Vasc. Surg. 27:69–80, 1998. doi:10.1016/S0741-5214(98)70293-9.
Wang, C., M. Garcia, X. Lu, Y. Lanir, and G. S. Kassab. Three-dimensional mechanical properties of porcine coronary arteries: a validated two-layer model. Am. J. Physiol. Heart Circ. Physiol. 291:H1200–H1209, 2006. doi:10.1152/ajpheart.01323.2005.
Wei, Y. G., and J. W. Hutchinson. Interface strength, work of adhesion and plasticity in the peel test. Int. J. Fracture 93:315–333, 1998. doi:10.1023/A:1007545200315.
Wulandana, R., and A. M. Robertson. An inelastic multi-mechanism constitutive equation for cerebral arterial tissue. Biomech. Model. Mechanobiol. 4:235–248, 2005. doi:10.1007/s10237-005-0004-z.
Yamaguchi, M., K. Sugimoto, C. A. Zamora, T. Takahashi, Y. Hayashi, and K. Sugimura. Placement of self-expanding stents with different diameters in the porcine venous system: an experimental study. J. Vasc. Interv. Radiol. 17:113–119, 2006.
Zhang, W., C. Herrera, S. N. Atluri, and G. S. Kassab. The effect of surrounding tissue on vessel fluid and solid mechanics. J. Biomech. Eng. 126:760–769, 2004. doi:10.1115/1.1824128.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Liu, Z., Liu, Y., Navia, J.A. et al. A Magnetic Approach to Decrease Stent Graft Endoleak: Ex-Vivo Validation. Ann Biomed Eng 37, 1727–1738 (2009). https://doi.org/10.1007/s10439-009-9741-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10439-009-9741-y