Stent longitudinal flexibility: A comparison of 13 stent designs before and after balloon expansion

• Published in: Catheterization and cardiovascular interventions Vol. 50; no. 1; pp. 120 - 124
• Main Authors: Ormiston, John A., Dixon, Simon R., Webster, Mark W.I., Ruygrok, Peter N., Stewart, James T., Minchington, Ian, West, Teena
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York John Wiley & Sons, Inc 01.05.2000; Wiley-Liss
• Subjects: angioplasty; Biological and medical sciences; Diseases of the cardiovascular system; Equipment Design; Equipment Safety; Evaluation Studies as Topic; flexibility; Humans; mechanical properties; Medical sciences; Pliability; Probability; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Stents; Stress, Mechanical; Human; Endoprosthesis; Treatment; Coronary artery; Instrumentation therapy; Mechanical properties; Instrumental dilatation; Technique; Flexibility; Comparative study; Biomedical engineering
• ISSN: 1522-1946; 1522-726X
• DOI: 10.1002/(SICI)1522-726X(200005)50:1<120::AID-CCD26>3.0.CO;2-T

Longitudinal flexibility is an important property of coronary stents, facilitating delivery and allowing the expanded stent to conform to vessel contour. Subjective descriptions of flexibility abound, but there are few independent quantitative data to aid stent selection. A three‐point bend test was employed to measure stiffness, the reciprocal of flexibility, for 13 stent designs in the unexpanded (bare) state, then after expansion with a 3.5‐mm balloon. For eight of the designs, stiffness of the proprietary stent/balloon delivery system was also measured. In the unexpanded state, there was a wide spread of stiffness, which ranged from 0.5 ± 0.2 to 91.5 ± 10.0 g force/mm, depending on design. Stiffness was least for the coil (Wiktor and Crossflex) and hybrid (AVE GFX and Bard XT) designs. The MultiLink was the most flexible and the Crown the stiffest of the slotted tube designs. All stents became stiffer upon expansion. For most manufacturer‐mounted stents, the delivery balloon was the main determinant of stent/balloon delivery system stiffness. Manufacturer‐mounted stent profile ranged from 1.15 ± 0.11 mm for the Jostent to 1.53 ± 0.05 mm for the MultiLink system. Independent quantitative assessment of characteristics such as flexibility and profile should aid rational comparison of stent designs. Cathet. Cardiovasc. Intervent. 50:120–124, 2000. © 2000 Wiley‐Liss, Inc.