Patients with Afib are at an increased risk of stroke.

Atrial fibrillation (Afib), or an irregular heartbeat, can cause blood to pool in a small pouch off the upper left chamber of the heart, known as the left atrial appendage (LAA). This pooling can cause the formation of blood clots which may lead to stroke.

Current Treatment Options

Oral Anticoagulants

Oral anticoagulants, also known as blood thinners, are often prescribed to prevent blood clot formation; however, they may not be well accepted due to an increased risk of bleeding and the need for ongoing monitoring.1


Left atrial appendage occlusion (LAAO) is a one-time procedure that aims to reduce the risk of strokes forming in the LAA and eliminate the need for long term daily oral anticoagulant therapy.

Hand with CLAAS device

A new device for treating the left atrial appendage

The CLAAS® System is a foam device designed to fit in each patient’s anatomy and seal the LAA to reduce the risk of stroke without the need for anticoagulants. The device is permanently placed in the heart by your physician during a single procedure.

How It Works

Clinical Studies

Claas device closeup Claas device closeup

The CLAAS System is being studied in three active clinical trials:

  • Conformal Early Feasibility (EFS) Study (US)
  • Conformal Prague Study (Prague, CR)
  • CONFORM Pivotal Trial

Data from the EFS and Prague studies have been published in peer-reviewed articles. The CLAAS device is limited to investigational use only and is not approved for use in any geography.

Presentations & Publications