Welcome

NOTE: Our May 3rd meeting slides can be downloaded here (6.7MB pdf).


Welcome to criticalimb.org. This site is a repository of information regarding the work done by the critical limb ischemia (CLI) Performance Goals Work Group of the Society for Vascular Surgery (SVS).

Background:
The CLI Performance Goals Work Group was appointed by SVS in December 2007 to recommend performance goals for new technology in the area of CLI. Members of the work group include Drs. Michael Conte (Co-Chair, University of California, San Francisco), Patrick Geraghty (Co-Chair, Washington University, Saint Louis), Andrew Bradbury (University of Birmingham, UK), Gregory Moneta (Oregon Health Sciences University, Portland), Mark Nehler (University of Colorado, Denver), Richard Powell (Dartmouth-Hitchcock Medical Center, Lebanon) and Anton Sidawy (Georgetown University, Georgetown).

Objective:
The primary goal of the work group was to define a set of risk-stratified objective performance goals (OPG) that may be considered appropriate for the evaluation of new endovascular and minimally invasive therapies in this area. CLI performance goals can also be used to support pre-market applications (PMA) to the FDA. The OPG could then be used by industry in single-arm device trials that could lead to approval for marketing.

Progress:
Over the course of the year-long project, the work group’s work was informed by a series of collaborative discussions with members of the FDA Peripheral Devices Branch, Division of Cardiovascular Devices, Center for Devices and Radiological Health. Data agreements were completed with trial sponsors and line-item data was obtained from several randomized trials in CLI. We obtained data from high quality trials of Open Surgery, Endovascular Therapy, and Natural History in the CLI population. Specific criteria for data quality including study population and follow-up assessments were established, and variables mapped across the combined datasets. Endpoints were defined and statistical analyses were then performed to describe pooled outcomes and develop risk-stratified OPGs. Ultimately only the Open Surgery control group was used to develop the OPGs because of critical limitations in the other historical datasets. The timepoint selected for safety endpoints was 30 days, and for all efficacy endpoints was one year.

A talk entitled “ Defining objective performance goals (OPG) for the treatment of critzical limb ischemia (CLI): Importance of risk stratification ”, summarizing the primary findings, was presented at the 2009 Vascular Annual Meeting in Denver, Colorado. The summary manuscript, along with an FDA commentary, will appear in the Journal of Vascular Surgery in Fall of 2009, and will be posted on this website when available.

Documentation:
Previous publications relevant to the three randomized control trials used in this effort can be found at our Literature page . Specific definitions of the endpoints which were developed can be found on our Outcomes page .

Results:
The majority of our semi-publicly available results can be found at these three links:

  • Open surgery
  • Endovascular
  • Natural History
  • These links can also always be found directly in the left sidebar, regardless of your current location.

    Each of these pages has both perioperative (1 month) and longer term (1 year kaplan-meier) results. To access these, scroll down to the risk factor of interest and click on the link at the intersection of the time point and endpoint desired. For more information on our primary identified risk groups please visit this page . This should open a new page with specific results, stratified by the covariate selected. For example, in the image below (from the Open Surgery page ) clicking on the circled kaplan-meier would open one year survival analysis for the amputation/reintervention free outcome (RAO) against the anatomical high-risk covariate. The survival analysis results pages consist of a cross-tabulation, a univariate KM analysis, a univariate Cox regression and (at the very bottom) an estimate of one year KM survival estimates and their 95% confidence intervals.

    For any questions regarding this website or the content within, please feel free to contact Sarah Murphy .