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EWOLUTION

Efficacy and safety of left atrial appendage closure with WATCHMAN in patients with or without contraindication to oral anticoagulation: 1-Year follow-up outcome data of the EWOLUTION trial

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Year of Publication: 2017

Authors: Lucas V. Boersma, Hueseyin Ince, Stephan Kische, ..., Martin W. Bergmann

Journal: Heart Rhythm

Citation: Heart Rhythm 2017;14:1302–1308

Link: http://dx.doi.org/10.1016/j.hrthm.2017.05.038

PDF: http://www.heartrhythmjournal.com/articl...27117307154/pdf

Clinical Question

What is the real-world efficacy and safety of WATCHMAN left atrial appendage closure in patients with atrial fibrillation, particularly those contraindicated for oral anticoagulation?

Bottom Line

WATCHMAN left atrial appendage closure demonstrated high procedural success (98.5%) and low stroke rates (1.1% annually) in real-world practice, even in patients contraindicated for oral anticoagulation.

        Major Points
        Largest prospective real-world registry of WATCHMAN device with 1025 patients
73% of patients were deemed unsuitable for oral anticoagulation therapy
High-risk population with mean CHA2DS2-VASc score of 4.5 and 31% history of major bleeding
Procedural success rate of 98.5% with adequate sealing (no leaks >5mm) in 99.7%
Annual ischemic stroke rate of 1.1% representing 84% relative risk reduction vs expected
Device thrombus occurred in 3.7% but was not correlated with stroke events
Most patients managed with antiplatelet therapy rather than oral anticoagulation

      

Design

Study Type: Prospective multicenter registry

Randomization:

Blinding: None - open label registry

Enrollment Period: October 2013 to May 2015

Follow-up Duration: 1 year

Centers: 47

Countries: Netherlands, Germany, Russia, United Kingdom, Ireland, Italy, Belgium

Sample Size: 1025

Analysis: Kaplan-Meier method for mortality and device thrombus rates, log-rank tests for time-to-event analysis, Fisher exact test for binomial proportions

Inclusion Criteria

Patients scheduled for WATCHMAN implant
Eligible according to appropriate local and international guidelines
Not participating in another trial
Not pregnant or of childbearing age
Willing, able, and of legal age to provide informed consent

Exclusion Criteria

Participating in another clinical trial
Pregnant or of childbearing potential
Unable or unwilling to provide informed consent

Baseline Characteristics

Characteristic	Control	Active
Age (years)		73.4 ± 8.9
Age ≥75 years		50.7%
Female sex		40.1%
CHA2DS2-VASc score		4.5 ± 1.6
HAS-BLED score		2.3 ± 1.2
HAS-BLED ≥3		40.0%
Contraindicated for OAC		73.3%
Congestive heart failure		34.2%
LVEF ≤40%		13.2%
Vascular disease		41.9%
Hypertension		86.4%
Diabetes		29.7%
Previous ischemic stroke/TIA		30.5%
Previous hemorrhagic stroke		15.1%
History of major bleeding		31.3%
Abnormal renal function		15.8%
Abnormal liver function		4.3%

Arms

Field	WATCHMAN Device
Intervention	Percutaneous left atrial appendage closure with WATCHMAN device followed by antiplatelet therapy (83%) or vitamin K antagonists (8%) per physician discretion
Duration	Permanent device implantation with variable anticoagulation duration

Outcomes

Outcome	Type	Intervention
Procedural success and long-term stroke prevention	Primary	98.5% implant success, 1.1% annual ischemic stroke rate
Adequate sealing (no leaks >5mm)	Secondary	99.7%
Device thrombus	Secondary	3.7%
Major bleeding (annual rate)	Secondary	2.6%
Ischemic stroke/TIA/systemic embolism (annual rate)	Secondary	1.5%
All-cause mortality at 1 year	Adverse	9.8%
Procedure-related serious adverse events within 7 days	Adverse	2.8%
Periprocedural death within 7 days	Adverse	0.4%

Subgroup Analysis

No differences in death, stroke, or bleeding rates were observed between patients with or without contraindication to anticoagulation. Half of stroke patients were still on discharge medication, half had changed to lower anticoagulation.

Criticisms

Lack of control arm limits full assessment of therapy benefit
Non-uniform postprocedural antithrombotic regimen at physician discretion
13% of patients lacked follow-up TEE/CT evaluation
Primary follow-up responsibility with participating centers rather than centralized
HAS-BLED bleeding risk calculations based on VKA patients may overestimate benefit in VKA-ineligible population
Detailed device thrombus management not systematically captured

Funding

Boston Scientific Corporation provided funding for the study

Based on: EWOLUTION (Heart Rhythm, 2017)