乌鸦传媒

A cost-modeling study indicates that, in patients with atrial fibrillation, treatment with the Watchman left atrial appendage closure device is more effective at reducing stroke risk at lower cost than either warfarin or the new oral anticoagulants (NOACs).

Both NOACs and the Watchman device were more cost-effective than warfarin because of their greater stroke risk reduction, but the difference was more apparent with the device-based intervention in the first years, according to the model developed by , of Mount Sinai Medical Center, New York, N.Y., and colleagues, writing in the

"Both NOACs and LAAC with the Watchman device were cost-effective relative to warfarin, but LAAC was also found to be cost-effective and to offer better value relative to NOACs," the researchers wrote, adding that the analysis "should be considered when formulating policy and practice guidelines" for stroke prevention in atrial fibrillation.

But in an editorial published with the paper, , of Tufts Medical Center in Boston, wrote that cost modeling has significant limitations that must be considered by clinicians and health policy makers.

In a telephone interview with 乌鸦传媒, Estes noted that the researchers were forced to make many assumptions given the uncertainty about future healthcare costs and long-term outcomes in patients treated with LAAC.

"This analysis is predicated on a lot of assumptions, and while it represents the best estimate of what might happen it is not necessarily reflective of real-world clinical practice," he said. "Projecting out over 10 to 20 years is a lot like trying to predict what the stock market will

The researchers developed a Markov model to assess the cost-effectiveness of the three stroke reduction strategies from the perspective of the Centers for Medicare & Medicaid Services (CMS) over a 20-year (lifetime) horizon. Afib patients were age 70 and had a moderate risk for stroke and bleeding.

Clinical event rates, stroke outcomes, and quality of life information came mostly from 4-year data and meta-analyses of warfarin and NOACs. Stroke risk reduction therapy costs, as well as cost of treatment of associated acute events and long-term care following disabling stroke, were presented in 2015 U.S. dollars.

The cost analysis found that:

• Relative to warfarin, LAAC was cost-effective at 7 years ($42,994/quality-adjusted life years [QALY]).
• NOACs were cost-effective relative to warfarin at 16 years ($48,446/QALY).
• LAAC was dominant over NOACs by year 5 and warfarin by year 10.
• At 10 years, QALYs were greater for LAAC than warfarin and NOACs (5,885 versus 5,601 and 5,751, respectively).

In sensitivity analyses designed to assess the impact of parameter uncertainty on model results, LAAC remained cost-effective relative to warfarin ($41,470/QALY at 11 years) and NOACs ($21,964/QALY at 10 years, even when procedure costs doubled).

"Both (LAAC and NOACs) demonstrated cost-effectiveness relative to warfarin, but only LAAC demonstrated cost saving by year 10 relative to warfarin and by year 5 relative to NOACs," the researchers wrote.

The Watchman device was approved by the FDA in March of this year after several years of regulatory rejections for use in high-risk patients with nonvalvular atrial fibrillation (NVAF) who, "have an appropriate rationale to seek a non-pharmacologic alternative to warfarin (Coumadin)."

In early November, the CMS announced that it would restrict coverage of the device, stating that coverage outside the research setting is not warranted because left atrial appendage closure with an implanted device

Given the device's rocky road to approval and post-approval setbacks, Estes said it would be difficult to predict "exactly what clinical niche the Watchman is going to carve out."

"It is coming out as an invasive option at the same time there are also more attractive pharmacologic options for lowering stroke risk," he said. "But I do believe there will be an expanding market when we find that sweet-spot niche of the right patient and the right centers performing left atrial appendage closure."

In his editorial, Estes wrote that the identification of patients who will benefit most from left atrial appendage closure will be an important objective of the Watchman clinical trial registry.

In his conversation with 乌鸦传媒, Estes said careful selection of centers performing the LAAC will also be a key factor in its success.

"This has been a 10-year process with multiple trials," he said. "I don't think this technology will be rapidly and widely adopted, but I do think gradual uptake in controlled settings with highly selected patients and highly selected centers is in everyone's best interest."

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