Not everyone is happy about the MBS listing for left atrial appendage occlusion (LAAO) for stroke prevention in non‑valvular atrial fibrillation being restricted to patients contraindicated to lifelong oral anticoagulation therapy.
Dr Karen Phillips, a cardiac electrophysiologist at HealthCare Partners in Brisbane, kicked off a debate at CSANZ 2018 with a spirited argument to open up the MBS item number given the procedure was clinically effective, cost effective and had a 100% compliance rate.
“This therapy works. So then why have the clinical guidelines and a number of regulatory approval bodies around the world ignored the evidence base and recommended LAAO for patients who are contraindicated for anticoagulants?”
She said the contraindications to anticoagulants were well-defined yet there was also little evidence of risk versus benefit in this group, especially at the time the recommendations were made.
Dr Phillips said the effect of restricting access to people with contraindications was their CHA2DS2-VASc started to climb reflecting increased comorbidities.
In a one-year follow-up of more than 1,000 patients from the European Watchman registry, an annual stroke rate of 1.1% was achieved but an unexpected all-cause mortality rate of 9.8%.
Similarly, in a smaller French registry for ‘all comers and all devices’ and a very high CHA2DS2-VASc, the stroke rate was 2.9% and the mortality rate was 9.3%.
“These are the unintended consequences of recommending it for this group of patients,” she said.
Quoting an unnamed colleague, she said: “The current clinical guidelines have basically severely skewed the use of LAAO such that some of the potential long-term benefits of this therapy may never be realised if it is reserved for the almost dead.”
Dr Phillips said LAAO therapy was also cost saving versus NOACs by year five in an arguably expensive US model.
In more conservative economic modelling from Germany and Canada – more comparable to Australian healthcare costs – Watchman was cost effective by year seven and cost saving by year eight versus NOACs.
“The current indication unfortunately is a budget decision and not a clinical indication, and unfortunately this is going to kick the can down the road for the healthcare payer.”
“What is the cost of a 65-year-old taking 10 years of NOAC therapy, followed by a bleeding complication and probably a costly hospitalisation, and then to be offered LAAO in their mid-70s?”
She said the FDA in the US took a long time to approve the therapy but ultimately gave a reimbursement and clinical indication according to the evidence.
“Patients with an increased risk of stroke, a CHA2DS2-VASc score of two or more who would ordinarily be suitable for anticoagulation but have a rationale to seek a non-pharmacological approach such as closure, could be considered for a Watchman implantation.”
However Professor Prash Sanders, from University of Adelaide and SAHMRI, recommended caution and said the limited evidence had been manipulated to suit supporters of LAAO.
“There are actually only two randomised controlled trials that have even been done with appendage closure, but a number of papers that have come out of these two studies each propagating a further message in terms of where this is indicated.”
“This is a re-analysis over and over again until you find the answer that you want. So we have got to be wary of this data.”
Professor Sanders said close examination of the data revealed the available studies included some unblinded analyses and spurious endpoints.
He added there were no studies comparing appendage closure to NOAC therapy, only extrapolation from comparisons with warfarin.
“In the era where we have had large anticoagulant studies, it’s important to put this into perspective.”
And there were recent safety signals with a French study showing appendage closure devices have a greater risk of device-related thrombus, corresponding with a higher risk of a further vascular event.
Professor Sanders called for more evidence that was independent of industry and more critical analysis of available evidence.
“There is going to be a role for this technology – it’s a question of where it fits – and our data doesn’t currently help us with this. Just because we can, doesn’t mean we should.”
Dr Phillips concluded with a call for patients to be given more choice, given NOACS weren’t a perfect solution.
“Patients do still need other options and other choices. They are still faced with major bleeding events for which LAAO can be an obvious alternative.”
“I think the importance of the discussion is to emphasise that we want patients to be involved in shared decision-making. Stroke prevention in atrial fibrillation is a complex area and we need to acknowledge their values and their preferences in addition to our own biases and preferences for therapy,” she said.