Artificial Valve Endocarditis Reduction Trial (AVERT): protocol of a multicenter randomized trial

J Heart Valve Dis. 1999 Mar;8(2):131-9.


Background and aim of the study: This article presents the protocol of the Artificial Valve Endocarditis Reduction Trial (AVERT), a multicenter, international randomized trial to assess the efficacy of the SilzoneTM coating of St. Jude Medical Masters Series mechanical heart valves in the prevention of prosthetic heart valve endocarditis (PVE). A total of 4,400 eligible patients will be randomized within three years of study commencement at 17 participating clinical centers in North America and Europe, with study completion within four years.

Eligibility criteria: Eligible patients are candidates for St. Jude mechanical valves with either the Silzone or conventional cuff, in the mitral and/or aortic position, who give informed written consent to participate. Major exclusion criteria are the presence of prosthetic valves that do not require replacement, and the need for tricuspid valve replacement. Bypass surgery and valve repair are allowed during the implant operation. Patients will be randomized using an envelope-based intraoperative randomization scheme, stratified by clinical center and by the presence of endocarditis at the time of surgery.

Follow up: Patients will be contacted at discharge, three months, and each anniversary of the implant procedure. A brief follow up survey, administered via clinic interview, telephone or mail, will elicit events associated with possible endocarditis (unexplained fever, worsening angina, hospitalization) that will initiate contact with the patient's following physician.

Outcome analysis: The primary PVE endpoint will be based upon a published algorithm, with two infectious disease specialists making the final determination of cases classified as possible endocarditis. Study data will be periodically reviewed by a Data Safety Monitoring Board. The primary analysis will be an intention-to-treat comparison of freedom from PVE curves between the Silzone and conventional cuff treatment groups.

Conclusions: AVERT will provide much-needed information on the effectiveness of Silzone in preventing PVE, as well as practice patterns and outcomes of valve replacement.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Clinical Protocols
  • Coated Materials, Biocompatible
  • Endocarditis, Bacterial / etiology
  • Endocarditis, Bacterial / prevention & control*
  • Follow-Up Studies
  • Heart Valve Diseases / surgery*
  • Heart Valve Prosthesis / adverse effects*
  • Heart Valve Prosthesis Implantation*
  • Heart Valves / surgery
  • Humans
  • Prosthesis-Related Infections / etiology
  • Prosthesis-Related Infections / prevention & control*
  • Randomized Controlled Trials as Topic / methods*
  • Silver / therapeutic use*
  • Surveys and Questionnaires
  • Treatment Outcome


  • Coated Materials, Biocompatible
  • Silver