What if someone with atrial fibrillation (AF) doesn’t tolerate warfarin or Novel Oral Anticoagulants (NOACs)? Some alternative treatments still reduce the risk of ischemic stroke in these patients and have better outcomes than doing nothing.
Treating the risk Atrial fibrillation is a common disease of ageing, affecting 2% of the population (or >10% in people over 80 years). The loss of atrial contractility in patients with AF results in sluggish flow in the left atrium and left atrial appendage (LAA) which is a remnant outpouching. As a result, the risk of clot formation and subsequent stroke (or embolism to other organs) is increased. Clot formation in AF patients tend to occur in the LAA (up to 90%).
The risk of stroke in AF patients tends to increase with age but other risk factors such as congestive cardiac failure, hypertension, diabetes, female sex and existing vascular disease also contribute to this risk (CHA,DS –VASc score). Currently, it is recommended that anyone with AF over the age of 65 or has at least one of the mentioned risk factors should be considered for oral anticoagulation and fluoroscopic guidance in a cathlab, the procedure takes approximately 30 minutes with patients discharged the following day. It carries minimal risk (<2% major bleeding, pericardial effusion, stroke). Patients can come off oral anticoagulation long-term after the procedure.
The safety and efficacy of the procedure was validated with the PROTECT-AF trial which randomised 707 patients with AF to receiving long-term oral anticoagulation (warfarin) versus left atrial appendage occlusion (Watchman device). The study found similar rates of ischaemic stroke in both groups (1.3% vs 1.1%) but significantly less stroke (of any cause), systemic embolism, and cardiovascular death in the left atrial appendage occlusion cohort at 3.8 years (1.5% absolute reduction). Antithrombotic treatment was given for at least six weeks after device implantation.
The most serious side-effect from oral anticoagulation is intracranial or gastro intestinal bleeding. Patients with high risk of bleeding (falls risk or underlying haematological disease) and AF, present a problem. New technique Left atrial appendage occlusion excludes the LAA from the circulation. It is a procedure that plugs the LAA with a special device (the Watchman device or Amulet device) delivered via the femoral vein. Performed under general anaesthesia with transesophageal echo
Currently, left atrial appendage occlusion is indicated in patients with AF who cannot take oral anticoagulation due to significant bleeding or an underlying haematological condition that precludes them from anticoagulation.
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