Skip to main content

Novel Bioresorbable Stent Design and Fabrication: Congenital Heart Disease Applications


The design and development of bioresorbable stents tailored for treatment of pediatric patients with congenital heart disease is described. First, we examined the mechanical properties of thermally annealed PL-32 and PL-18 PLLA fibers using an Instron 5565 tensiometer. Stent designs ranging from 3 to 6 mm diameter and up to 15 mm length were examined. We adapted a winding jig to enable fabrication of coiled stents consisting of double-opposed helices. Double-opposed helical stents were thermally annealed for strength and flexibility. Following winding, stents were crimped on appropriately sized balloon catheters, and then expanded in a 37 °C water bath. Mechanical characteristics were measured as a function of stent size and design. PL-32 fiber has stronger mechanical properties with a 33% increase in stiffness. The opposing coil design improves stent expansion for larger stent designs. In addition, the stiffness of small diameter double-opposed helical stents was higher than values for the larger diameter stents hence having higher collapse pressure 1.07 ± 0.02 atm and the resistance to external pressure-induced collapse for larger diameter stents was lower decreasing to 0.63 ± 0.02 atm. The larger deformations at larger diameters were experienced since mechanical strain in the stent fibers is increased under these conditions. This led to increased twisting of the coils and higher striation angle measurements ranging from 17.5° to 26.7° from smaller to larger stents. The large diameter double opposed helix stents showed larger axial shortening of 3–3.5% and higher elastic recoil increase of 1.12%. The PL-32 stents also showed a slower degradation of 5% over 6 months. Modulating the number of coils within the double helical stent design and winding in opposing directions favorably affects stent mechanical properties.

This is a preview of subscription content, access via your institution.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12


  1. 1.

    Babapulle, M. N., and M. J. Eisenberg. Coated stents for the prevention of restenosis: part II. Circulation 106:2859–2866, 2002.

    Article  Google Scholar 

  2. 2.

    Bruneau, B. G. The developmental genetics of congenital heart disease. Nature 451:943–948, 2008.

    Article  Google Scholar 

  3. 3.

    Engelberg, I., and J. Kohn. Physico-mechanical properties of degradable polymers used in medical applications: a comparative study. Biomaterials 12:292–304, 1991.

    Article  Google Scholar 

  4. 4.

    Feltes, T. F., E. Bacha, R. H. Beekman, III, J. P. Cheatham, J. A. Feinstein, A. S. Gomes, Z. M. Hijazi, F. F. Ing, M. Moor, R. W. Morrow, C. E. Mullins, K. A. Taubert, and E. M. Zahn. Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association. Circulation 123:2607–2652, 2011.

    Article  Google Scholar 

  5. 5.

    Forbes, J. T., E. Rodriguez-Cruz, Z. Amin, L. N. Benson, T. E. Fagan, W. E. Hellenbrand, L. A. Latson, P. Moore, C. E. Mullins, and J. A. Vincent. The genesis stent: a new low-profile stent for use in infants, children, and adults with congenital heart disease. Catheter. Cardiovasc. Interv. 59:406–414, 2003.

    Article  Google Scholar 

  6. 6.

    Frank, Ing. Stents: what’s available to the pediatric interventional cardiologist? Catheter. Cardiovasc. Interv. 57:374–386, 2002.

    Article  Google Scholar 

  7. 7.

    Grabow, N., M. Schlun, K. Sternberg, N. Hakansson, S. Kramer, and K. P. Schmitz. Mechanical properties of laser cut poly(l-lactide) micro-specimens: implications for stent design, manufacture, and sterilization. J. Biomech. Eng. 127:25–31, 2005.

    Article  Google Scholar 

  8. 8.

    Hara, H., M. Nakamura, J. C. Palmaz, and R. S. Schwarts. Role of stent design and coatings on restenosis and thrombosis. Adv. Drug Deliv. Rev. 58:377–386, 2006.

    Article  Google Scholar 

  9. 9.

    Hoffman, J. I. E., and S. Kaplan. The incidence of congenital heart disease. J. Am. Coll. Cardiol. 39:1890–1900, 2002.

    Article  Google Scholar 

  10. 10.

    Migliavacca, F., L. Petrini, V. Montanari, I. Quagliana, F. Auricchio, and G. Dubini. A predicative study of the mechanical behavior of coronary stents by computer modeling. Med. Eng. Phys. 27:13–18, 2005.

    Article  Google Scholar 

  11. 11.

    Nishio, S., K. Kosuga, K. Igaki, M. Okada, E. Kyo, T. Tsuji, E. Takeuchi, Y. Inuzuka, S. Takeda, T. Hata, Y. Takeuchi, Y. Kawada, T. Harita, J. Seki, S. Akamatsu, S. Hasegawa, N. Bruining, S. Brugaletta, S. Winter, T. Muramatsu, Y. Onuma, P. Serruys, and S. Ikeguchi. Long-term (>10 years) clinical outcomes of first-in-man biodegradable poly-l-lactic acid coronary stents: Igaki-Tamai stents. Circulation 125:2343–2353, 2012.

    Article  Google Scholar 

  12. 12.

    Peters, B., P. Ewert, and F. Berger. The role of stents in the treatment of congenital heart disease: current status and future perspectives. Ann. Pediatr. Cardiol. 2:3–23, 2009.

    Article  Google Scholar 

  13. 13.

    Rosa, D. S., C. G. F. Guedes, and M. A. G. Bardi. Evaluation of thermal, mechanical and morphological properties of PCL/CA and PCL/CA/PE-g-GMA blends. Polym. Testing 26:209–215, 2007.

    Article  Google Scholar 

  14. 14.

    Serruys, P. W., J. A. Orminston, Y. Onuma, E. Regar, N. Gonzalo, H. M. Garcia–Garcia, N. Bruining, C. Dorange, K. M. Herbert, S. Veldhof, M. Webster, L. Thuesen, and D. Dudek. A bioabsorbable everolimus-eluting coronary stent system (ASORB): 2-year outcomes and results from multiple imaging methods. Lancet 373:897–910, 2009.

    Article  Google Scholar 

  15. 15.

    Sfyroeras, G. S., A. Koutsiaris, C. Karathanos, A. Giannakopoulos, and A. D. Giannoukas. Clinical revelance and treatment of carotid stent fractures. J. Vasc. Surg. 51:1280–1285, 2010.

    Article  Google Scholar 

  16. 16.

    Su, S. H., R. Y. N. Chao, C. L. Landau, K. D. Nelson, R. B. Timmons, R. S. Meidell, and R. C. Eberhart. Expandable bioresorbable endovascular stent. I. Fabrication and properties. Ann. Biomed. Eng. 31(6):667–677, 2003.

    Article  Google Scholar 

  17. 17.

    Sullivan, T. M., S. D. Ainsworth, E. M. Langan, S. Taylor, B. Snyder, D. Cull, J. Youkey, and M. Laberge. Effect of endovascular stent strut geometry on vascular injury, myointimal hyperplasia, and restenosis. J. Vasc. Surg. 36:143–149, 2002.

    Article  Google Scholar 

  18. 18.

    Tamai, H., K. Igaki, E. Kyo, K. Kosuga, A. Kawashima, S. Matsui, et al. Initial and 6-month results of biodegradable poly-l-lactic acid coronary stents in humans. Circulation 102:399–404, 2000.

    Article  Google Scholar 

  19. 19.

    Topol, E. J. Textbook of Interventional Cardiology, 4th ed. Pennsylvania: Saunders, 2003.

    Google Scholar 

  20. 20.

    Tsuji, H., and Y. Ikada. Properties and morphologies of poly(l-lactide): 1. Annealing condition effects on properties and morphologies of poly(L-lactide). Polymer 36:2709–2716, 1995.

    Article  Google Scholar 

  21. 21.

    Unverdorben, M., A. Spielberger, M. Schywalsky, D. Labahn, S. Hartwig, M. Schneider, D. Lootz, D. Behrend, K. Schmitz, R. Degenhardt, M. Schaldach, and C. Vallbracht. A polyhyroxybutyrate biodegradable stent: preliminary experience in the rabbit. Cardiovasc. Intervent. Radiol. 25:127–132, 2002.

    Article  Google Scholar 

  22. 22.

    Vilijanmaa, M., A. Sodergard, R. Mattila, and P. Tormala. Hydrolic and environmental degradation of lactic acid based hot melt adhesives. Polym. Degrad. Stab. 78:269–278, 2002.

    Article  Google Scholar 

  23. 23.

    Weir, N. A., F. J. Buchanan, J. F. Orr, D. F. Farrar, and A. Boyd. Processing, annealing, and sterilization of poly-L-lactide. Biomaterials 25:3939–3949, 2004.

    Article  Google Scholar 

  24. 24.

    Welch, T. R. Advances in helical stent design and fabrication, thermal treatment and structural interaction studies of the simulated plaque-laden artery. Dissertation, Joint Biomedical Engineering Program the University of Texas at Arlington and the University of Texas Southwestern Medical Center at Dallas, 2009.

  25. 25.

    Welch, T. R., R. C. Eberhart, and C. J. Chuong. Characterizing the expansive deformation of a bioresorbable polymer fiber stent. Ann. Biomed. Eng. 36(5):742–751, 2008.

    Article  Google Scholar 

  26. 26.

    Welch, T. R., R. C. Eberhart, and C. J. Chuong. The Influence of Thermal Treatment on the Mechanical Characteristics of a PLLA Coiled Stent. J. Biomed. Mater. Res. B Appl. Biomater. 90(1):302–311, 2009.

    Google Scholar 

  27. 27.

    Wholey, M. H., E. A. Finol. Designing the ideal stent. Stent cell geometry and its clinical significance in carotid stenting. Endovascular Today March: 25–34, 2007.

  28. 28.

    Zilberman, M., and R. C. Eberhart. Drug-eluting bioresorbable stents for various applications. Annu. Rev. Biomed. Eng. 8:153–180, 2006.

    Article  Google Scholar 

  29. 29.

    Zilberman, M., K. D. Nelson, and R. C. Eberhart. Mechanical properties and in vitro degradation of bioresorbable fibers and expandable fiber-based stents. J. Biomed. Mater. Res. B Appl. Biomater. 74B:792–799, 2005.

    Article  Google Scholar 

Download references


This research was supported by funds from the Departments of Cardiovascular and Thoracic Surgery and Pediatrics, UT Southwestern Medical Center.

Author information



Corresponding author

Correspondence to Tré R. Welch.

Additional information

Associate Editor Ajit P Yoganathan oversaw the review of this article.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Welch, T.R., Eberhart, R.C., Reddy, S.V. et al. Novel Bioresorbable Stent Design and Fabrication: Congenital Heart Disease Applications. Cardiovasc Eng Tech 4, 171–182 (2013).

Download citation


  • Thermal treatment
  • PLLA stent
  • Bioresorbable polymer
  • Pediatrics