Expandable bioresorbable endovascular stent. I. Fabrication and properties.
A bioresorbable, expandable poly(L-lactic acid) stent has been designed, based on a linear, continuous coil array principle, by which multiple furled lobes convert to a single lobe upon balloon expansion, without heating. Stent strength and compliance are sufficient to permit deployment by a conventional balloon angioplasty catheter. Several multiple lobe configurations were investigated, with expansion ratios ranging from 1.4 to 1.9 and expanded diameters ranging from 2.3 to 4.7 mm. Compression resistance of the expanded stent is dependent on fiber coil density and fiber ply. A range sufficient for endovascular service was obtained, with less than 4% elastic recoil in six day saline incubation studies. Surface plasma treatment with di(ethylene glycol) vinyl ether significantly reduced platelet adhesion in a 1 h porcine arteriovenous shunt model. Patency was maintained in one week implant studies in the porcine common femoral artery. However, a strong inflammatory response, and significant reduction of the vascular lumen were observed following two weeks implantation. The design principles and fabrication techniques for this bioresorbable stent are sufficiently versatile that a broad range of applications can be addressed. Much work remains to be done, including long-term evaluation of the inflammatory response, and of polymer degradation. The results of this study demonstrate the feasibility of expandable biodegradable stent design and deployment by conventional means.
Su
Shih-Horng
SH
Joint Program in Biomedical Engineering, the University of Texas at Arlington and the University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
Chao
Robert Y N
RY
Landau
Charles L
CL
Nelson
Kevin D
KD
Timmons
Richard B
RB
Meidell
Robert S
RS
Eberhart
Robert C
RC
D020341:Absorbable Implants; D000818:Animals; D001794:Blood Pressure; D001807:Blood Vessel Prosthesis / Q000009:adverse effects*; D020099:Coated Materials, Biocompatible / Q000009:adverse effects / Q000138:chemical synthesis; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods; D005026:Ethylene Glycols / Q000009:adverse effects; D005263:Femoral Artery / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D019344:Lactic Acid; D009038:Motion; D015539:Platelet Activation; D011091:Polyesters; D011108:Polymers; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology* / Q000473:pathology; D015607:Stents / Q000009:adverse effects*; D013552:Swine; D014753:Vinyl Compounds / Q000009:adverse effects
D020099:Coated Materials, Biocompatible; D005026:Ethylene Glycols; D011091:Polyesters; D011108:Polymers; D014753:Vinyl Compounds; D019344:Lactic Acid; C033616:poly(lactide); C074255:ethylene glycol monovinyl ether