During a debate session on the second day of the ESC2012, Munich, Germany, the following question was raised: Is left atrial appendage (LAA) occlusion ready for widespread use in clinical practice? Whilst no one doubts the potential for this relatively new technique, the consensus is that more evidence-based data is still required before the technique is used in patients with atrial fibrillation.
LAA Occlusion shows great promise for the management of AF
“To date, there are 62 centres in Germany offering LAA-occlusion,” states Professor Thomas Lewalter from the University of Munich, Munich, Germany. “This treatment is readily available, safe and effective.”
Professor Lewalter backed his assertion by citing results from the PROTECT AF trial, carried out in 2009. This trial still remains the only randomised controlled trial to compare LAA-Occlusion with standard warfarin therapy. “With anticoagulation, bleeding is the main risk. You are fighting within a narrow therapeutic band outside of which is a significant risk of bleeding,” he explains.
The PROTECT AF trial compared Watchman LLA Closure Technology® with long-term warfarin therapy. In this trial 87% of the patients receiving LLA-Occlusion were able to discontinue warfarin after 45 days. “This is a strong hint that occlusion is non-inferior than the control group, and has a significantly lower bleeding risk,” he says, adding that: “The combined use of 2D and 3D imaging makes implantation much safer.”
A key factor that makes LL-Occlusion an attractive treatment option is that the left atrial appendage is the main source of AF-related embolisms, with over 90% originating from this area. Furthermore, novel anticoagulation agents still have their weak points, says Professor Lewalter. “Gastrointestinal bleeding is still one of the major bleeding sources, and all the new drugs depend on renal clearance which adds complications in patients with renal deficiency.”
More data needed before LAA-Occlusion is used in patients
On the other side of the coin, Professor Stuart J. Connolley from McMaster University, Ontario, Canada, believes that although LAA-Occlusion shows great potential, more randomized controlled trials are needed to determine the efficacy and safety in patients with AF.
“LAA-Occlusion is not ready for patients in general practice because there is insufficient evidence that it prevents stroke and embolism,” he says, adding that a greater understanding of the pathophysiology is needed. “All emboli do not come from the left atrial appendage. It is an important source, but it’s certainly not the only source.”
Professor Connolley argues that there simply isn’t enough data obtained from randomized controlled trials to justify using LAA-Occlusion as an alternative treatment to anticoagulant agents, stating that PROTECT-AF is the only trial that has compared LAA-Occlusion with long-term warfarin therapy.
“We need to take into account the new anticoagulants, which are non-inferior or superior to warfarin in terms of efficacy,” he says, stating that this is exemplified by the RELY trial. “If you look at the data, haemorhagic stroke has virtually been abolished [with novel agents], we’re down to baseline.”
And although Professor Connolley recognizes the potential benefits of LAA-Occlusion, he advises caution. “It is our responsibility to ensure we don’t rush into using this treatment before it is ready, before we have data. We need to become more evidence-based and rigorous in our approach.”