Abstract

Atrial fibrillation (AF) is associated with life-threatening thromboembolism. Most emboli stem from thrombosis in the left atrial appendage (LAA). The current treatment of choice is oral anticoagulants (OACs), but a small proportion of patients cannot take OACs predominantly because of the so-called unacceptable bleeding risks. However, many who initially accept OACs subsequently stop therapy or reduce the OAC treatment to a potentially non-effective dose leaving them exposed to thromboembolic risk. A relatively simple alternative therapy involves the catheter-based insertion of a LAA closure (LAAC) device to prevent thromboembolism from the LAA. There is a considerable evidence base for this therapy consisting of clinical trials and observational data which suggests comparable therapeutic efficacy with a possible small excess of ischaemic strokes. Although LAAC has been very closely examined by regulators and approved for market release, guidelines from most professional societies give only weak recommendations for use of this device which may be the only known effective therapy available to some at-risk AF patients. Guidance materials from the same societies more enthusiastically endorse LAAC. Clinical practice is running well ahead of the guidelines because equipoise has been lost by physicians faced with patients for whom they have no other effective therapy. Guideline writers are correct in providing recommendations which are less strong for LAAC than for OACs, for those who are able and willing to take OAC treatment, but for those who are not, a stronger recommendation is needed. But, should the guidelines lag behind or leap ahead of the available evidence?