A new study suggests that selected patients with atrial fibrillation have better outcomes with left atrial appendage occlusion versus lifelong treatment with oral anticoagulants.
In Denmark, 120,000 people have atrial fibrillation, a condition in which the atrial chambers of the heart beat rapidly and irregularly. Atrial fibrillation slows the flow of blood in the atria and increases the risk of blood clots forming in the left atrial appendage, a small ear-shaped sac attached to the left atrium. Thrombotic material can detach from the left atrial appendage and be transported by the bloodstream to the brain, causing a stroke.
Lifelong oral anticoagulants are prescribed to prevent atrial fibrillation from causing stroke. This effectively prevents clots from forming but also increases the risk of severe bleeding.
A new Danish study suggests that selected patients with atrial fibrillation may benefit from left atrial appendage occlusion, a percutaneous catheter procedure in which a cardiologist inserts an implant into the heart through a catheter inserted into the femoral vein in the groin. Once in place, the implant closes and seals off (occludes) the left atrial appendage, thereby preventing blood clots from forming and detaching from the appendage. The left atrial appendage is a fetal remnant that we do not need.
The new study shows that this procedure reduces the risk of stroke to the same level as treatment with oral anticoagulants. However, left atrial appendage occlusion also substantially reduces the risk of bleeding because oral anticoagulants are no longer necessary.
“Some patients with atrial fibrillation cannot tolerate oral anticoagulants because they have already experienced severe bleeding or have an increased risk of bleeding. This procedure will be attractive for them because it reduces their risk of stroke for the rest of their lives and they do not have to remember taking oral anticoagulants daily,” explains a researcher behind the study, Jens Erik Nielsen-Kudsk, Clinical Professor, Aarhus University and Senior Physician, Department of Cardiological Medicine B, Aarhus University Hospital.
The research has been published in JACC: Cardiovascular Interventions.
Two-year follow-up of 1,078 patients who underwent left atrial appendage occlusion
The researchers compared the risk of stroke and of severe bleeding for left atrial appendage occlusion versus the latest generation of oral anticoagulants, such as dabigatran (Pradaxa®), apixaban (Eliquis®), rivaroxaban (Xarelto®) or edoxaban (Lixiana®).
This part of the study included 1,078 patients from 61 cardiac centres in 17 countries who underwent left atrial appendage occlusion and were subsequently followed up for 2 years.
This group was compared with a similar group of patients in Denmark who had atrial fibrillation based on validated Danish registries, including the Danish National Patient Registry and the Danish National Prescription Registry. They were treated with the latest generation of oral anticoagulants and matched by propensity score based on covariates including age, heart failure, hypertension, risk of bleeding, diabetes, prior stroke or transient ischaemic attack or thromboembolism so that the groups were comparable.
Following matching, the patients who underwent left atrial appendage occlusion and those taking anticoagulants had the same expected risk of stroke and of severe bleeding at baseline.
Reduced risk of stroke and death
The results suggest that left atrial appendage occlusion may provide benefits over oral anticoagulants.
· The risk of stroke was similar in the groups.
· Left atrial appendage occlusion reduced the risk of severe bleeding by 38% versus oral coagulants. According to Jens Erik Nielsen-Kudsk, this is because anticoagulants are rendered unnecessary.
· The study also showed that left atrial appendage occlusion reduced the risk of death by 47% versus oral anticoagulants. Jens Erik Nielsen-Kudsk is surprised by the scale of this risk reduction, but fewer deaths from severe bleeding may be part of the explanation.
“These findings are interesting and thought-provoking and might seem to be too good to be true. Nevertheless, the results suggest that patients who do not have good outcomes with anticoagulants may benefit from left atrial appendage occlusion, a simple procedure that only takes 40 minutes under local anaesthesia,” says Jens Erik Nielsen-Kudsk. He emphasizes, however, that this was not a randomized controlled trial and that the design limits any definitive conclusions.
More people may benefit from left atrial appendage occlusion
According to Jens Erik Nielsen-Kudsk, the results suggest that further studies should identify which people with atrial fibrillation may benefit from left atrial appendage occlusion instead of oral anticoagulants.
Many people do not have good expected outcomes with oral anticoagulants, including those likely to experience severe bleeding, those assessed as having a high risk of severe bleeding and those who might have poor adherence with oral anticoagulants and therefore have an increased risk of stroke.
“Even more people may need left atrial appendage occlusion – not simply those at very high risk but also a wider group with atrial fibrillation at moderate risk,” explains Jens Erik Nielsen-Kudsk.
New clinical trial imminent
Jens Erik Nielsen-Kudsk and colleagues have initiated a large randomized clinical trial in Denmark, Norway, Sweden and Finland (Occlusion AF trial) to investigate whether other people with atrial fibrillation can benefit from left atrial appendage occlusion. The researchers are randomizing people with atrial fibrillation and prior stroke or transient ischaemic attack for either left atrial appendage occlusion or oral anticoagulants.
“These people have a very high risk of stroke, and we want to show that they can benefit from left atrial appendage occlusion instead of lifelong oral anticoagulants,” says Jens Erik Nielsen-Kudsk.