Are self-expanding stents superior to balloon-expanded in dilating aortas? An experimental study in pigs

Research output: Contribution to journalArticle

Abstract

OBJECTIVE: To study the stent/vessel interaction and distensibility following the natural increase in vascular diameter using self-expanding and balloon-expanded stents. DESIGN: Open experimental study. SETTING: Animal laboratory, university hospital. MATERIALS AND METHODS: Eight Palmaz (P) and eight Gianturco (G) stents were transluminally placed in the infrarenal aortas of 16 pigs. Pulsatile diameter changes above, at and below the stents were non-invasively monitored with an ultrasound phase-locked echo-tracking system before and immediately after stenting and at 4 and 18 weeks. Blood pressure was registered intra-arterially and stiffness (beta) was calculated. Intravascular ultrasound (IVUS) was performed at 18 weeks. RESULTS: Median weight increased from 20 kg (19-26) to 93 kg (62-130). Diameter of the aorta increased 60%. In group P no pulsatile diameter change could be measured at the stent (beta = infinity). In group G stenting increased stiffness from beta 20.7 (9.2) to 43.2 (8.0) (p < 0.05). After 18 weeks stiffness returned to beta 20.1 (12.4). Expanded, median diameter of the P stents was 7.4 (0.8) mm, not increasing after 18 weeks. Initial diameter of the G stents was 7.8 (1.0) mm, increasing 56% to 12.2 (2.3) mm (p < 0.05). IVUS revealed the G stents to be well attached to the vascular wall, but five P stents were detached within half of the circumference. CONCLUSION: Self-expanding stents follow the pulsatile diameter change of the vessel wall, not adversely affecting distensibility after 18 weeks. They show good attachment despite 56% dilation. In contrast, the balloon-expanded stents do not show pulsatile movement and may detach during vessel diameter increase. This may be of importance when choosing stents for endovascular treatment of abdominal aortic aneurysms.

Details

Authors
  • Peter Mangell
  • Martin Malina
  • K Vogt
  • Mats Lindh
  • T Schroeder
  • B Risberg
  • J Brunkwall
  • T Länne
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Surgery

Keywords

  • Endovascular stents, Aorta, Ultrasound, Diameter, Distensibility
Original languageEnglish
Pages (from-to)287-294
JournalEuropean Journal of Vascular and Endovascular Surgery
Volume12
Issue number3
Publication statusPublished - 1996
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Emergency medicine/Medicine/Surgery (013240200), Medical Radiology Unit (013241410), Surgery Research Unit (013242220)