EWOLUTION
(2017)Objective
To evaluate real-world efficacy and safety of left atrial appendage closure with WATCHMAN device in patients with or without contraindication to oral anticoagulation
Study Summary
• Ischemic stroke rate was 1.1% annually (84% relative risk reduction vs expected)
• Major bleeding rate was 2.6% annually despite 73% of patients being contraindicated for anticoagulation
Intervention
Left atrial appendage closure with WATCHMAN device
Inclusion Criteria
Patients scheduled for WATCHMAN implant according to European Society of Cardiology guidelines, high stroke risk
Study Design
Arms: Single arm prospective registry - WATCHMAN device implantation
Patients per Arm: 1025 patients enrolled, 1005 successful implants
Outcome
• High procedural success with minimal residual flow
• Device thrombus occurred in 3.7% of patients but was not correlated with stroke events
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
Study Design
- Study Type
- Prospective multicenter registry
- Randomization
- No
- Blinding
- None - open label registry
- Sample Size
- 1025
- Follow-up
- 1 year
- Centers
- 47
- Countries
- Netherlands, Germany, Russia, United Kingdom, Ireland, Italy, Belgium
Primary Outcome
Definition: Procedural success and long-term stroke prevention
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| 98.5% implant success, 1.1% annual ischemic stroke rate | - |
Limitations & 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
Citation
Heart Rhythm 2017;14:1302–1308