Proceedings from the Workshop on Preclinical Testing for Endovascular Grafts - July 31 - August 1, 2001

Transcripts of the meeting are available at: http://www.fda.gov/ohrms/dockets/dockets/01N_0463/01n0463.htm

Introduction

Since their introduction into clinical trials in the United States, endovascular aortic grafts have shown various types of problems. Although details of design and construction vary between different endovascular grafts and the failure modes have had a variety of causes and clinical effects, it remains common to all endovascular grafts that pre-clinical testing did not predict these failures. The need to improve pre-clinical testing in an attempt to reduce clinical device failures resulted in an FDA-sponsored workshop on endovascular graft pre-clinical testing held in Rockville, Maryland, USA on July 31-August 1, 2001.

Format

The workshop was not designed as a consensus conference. Instead, it provided a forum for bringing stakeholders together to define the problems and to identify areas of agreement and disagreement. The workshop had 34 invited participants who represented device manufacturers, the medical community, FDA and testing facilities, and international attendance by over 120 people. [Attendance List]

Outcome

Discussion centered on (1) defining the physiologic, anatomic and morphologic characteristics of abdominal aortic aneurysms (AAAs) before and after endovascular graft treatment; (2) identifying the types of failures that have been observed clinically; and (3) determining which characteristics should be considered during pre-clinical modeling to better predict clinical performance. Attendees agreed to the need to better define and address anatomical characteristics and changes in the aneurysm in order to optimize pre-clinical testing. There was much discussion and little agreement on the importance of flow related forces on graft performance or the need or ability to define and model physiologic compliance during durability testing. The discussion and conclusions are summarized in a paper recently published by the Journal of Vascular Surgery. Detailed proceedings from the workshop are provided with additional links, below.

Conclusion

The Workshop raised awareness of significant performance issues and the challenges of modeling the extremely variable and relatively undefined environment of AAAs. Through the interactive format of the workshop, participants identified areas of pre-clinical testing, device design, and aspects of the simulated environment that require further consideration.

 Proceedings of the Workshop

A Homework Assignment was completed by invited participants in preparation for the Workshop. The respondents' answers were compiled prior to the meeting, and formed the basis for the discussion.

Proceedings from Tuesday, July 31, 2001

Introductory Remarks: Jim Dillard, Hugh G. Beebe, Dorothy Abel, Megan Moynahan

Transcript - Introduction (WORD document)

"The physiologic, anatomic, and morphologic characteristics of AAA, with or without iliac

involvement"

Hugh G. Beebe

[Slides 1] [Transcript 1 - Beebe - WORD document]

"What the current imaging methods can and cannot measure in AAA’s"

Barry Katzen

[Slides 2 - not currently available] [Transcript 2 - Katzen - WORD document]

Working Session

Question #1: Morphologic and Physiologic Characteristics Pre-Implant

[Table 1 - WORD document]

"The physiologic, anatomic, and morphologic environment of endovascular grafts used for AAA, when implanted, and over time."

Juan Parodi

[Slides 3 - not currently available] [Transcript 3 - Parodi - WORD document]

Working Session

Question #2: Morphologic and Physiologic Characteristics Post-Implant and Over Time

[Table 2 - WORD document]

"Failures of endovascular grafts that have been observed clinically" Geoff White

[Slides 4 - not currently available] [Transcript 4 - White - WORD document]

Working Session

Question #3: Failure Modes

[Table 3 - WORD document]

"Failure modes of endovascular grafts that may be simulated through pre-clinical testing and

clinical characteristics that need additional consideration in these tests"

Michael Lawrence- Brown

[Slides 5] [Transcript 5 - MLB - WORD document]

Working Session

Question #4: Pre-clinical Testing

[Table 4 - WORD document]

 

Proceedings from Wednesday, August 1, 2001

Working Session

Question #5: Discussion on Pre-Clinical Testing

[Table 5 - WORD document]

"The difficulty of simulating clinical conditions in pre-clinical testing"

Thomas Fogarty

[Slides 6 - not currently available] [Transcript 6 - Fogarty - WORD document]

Working Session

Question #6: Unresolved Issues

[Table 6 - WORD document]

"Advances in simulating clinical conditions outside of the clinic"

Mark Fillinger

[Slides 7 - not currently available] [Transcript 7 – Fillinger - WORD document]