Highlights from

ACC 2020

Together with World Congress of Cardiology

Virtual 28 - 30 March 2020

LAAO Watchman registry data positive

Real-world evidence from the National Cardiovascular Data Registry (NCDR) Left Atrial Appendage Occlusion (LAAO) registry of patients implanted percutaneously with the Watchman device reveals a high implant success rate in addition to a low rate of in-hospital complications.

Dr James Freeman (Yale University School of Medicine, USA) presented the observational, non-randomised, post-approval analysis from the registry of periprocedural outcomes of the Watchman LAAO device, which includes data from >38,000 patients, [1]. The study was simultaneously published by the Journal of the American College of Cardiology [2].

The approval of LAAO to prevent stroke in patients with atrial fibrillation (AF) was established in 2015, based on 2 randomised trials, yet post-approval clinical data are limited [3,4]. To qualify for Medicare reimbursement in the USA, hospitals have been required to report all Watchman device procedures to the NCDR LAAO registry, with the intent to capture patient, hospital, and physician characteristics and in-hospital adverse event rates.

Compared with the original trials, the registry cohort was older (mean patient age was 76.1±8.1 years) and had more comorbidities (see Table). Furthermore, the mean CHA2DS2-VASc score for AF stroke risk determination was 4.6±1.5 (approximately 10-12% risk of stroke), and the mean HAS-BLED score for major bleeding was 3.0±1.1.

Hospitals performed a median number of 30 annual LAAO procedures, with a median of 12 per physician. Procedures were cancelled or aborted in 7% of cases; among cases in which a device was deployed, 98.1% were implanted with <5 mm leak. Major in-hospital adverse event rates were lower when compared to the original trials, occurring in 2.16% of patients, with the most common complications being pericardial effusion requiring intervention (1.39%) and major bleeding (1.25%), while stroke (0.17%) and death (0.19%) were rare. The registry suggests that this procedure and device are safe and effective in managing stroke risk in a real-world setting with heterogeneous patient characteristics and comorbidities. However, without a control group, Dr Freeman cautioned, unmeasured confounders could influence the interpretation. For example, the adverse events reporting relies on site-reported data, which may be under-reported. Consequently, adverse events may be underestimated in this registry. However, overall, these registry data support the clinical trial data.

Keywords: Watchman, Left Atrial Appendage Occlusion, LAAO device, stroke, atrial fibrillation, NCDR LAAO registry, bleeding.

Table: Patient characteristics LAAO registry compared with other trials [1]

Table- Patient characteristics LAAO registry compared with other trials

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The content and interpretation of these conference highlights are the views and comments of the speakers/authors.