PINNACLE FLX
(2023)Objective
To evaluate the safety and efficacy of the next-generation WATCHMAN FLX left atrial appendage closure device in patients with nonvalvular atrial fibrillation at 2 years
Study Summary
• The device demonstrated 100% effective LAA closure at 1 year with superior safety profile including no device embolizations
• Major bleeding occurred in 10.1% of patients at 2 years, with most events occurring within 6 months when on anticoagulation
Intervention
WATCHMAN FLX left atrial appendage closure device implantation
Inclusion Criteria
Nonvalvular atrial fibrillation with CHA2DS2-VASc score ≥2 (men) or ≥3 (women), appropriate rationale for left atrial appendage closure, able to take prescribed post-implant antithrombotic medication regimen
Study Design
Arms: Single-arm study with WATCHMAN FLX device
Patients per Arm: 395 successfully implanted patients
Outcome
• Primary effectiveness endpoint met with 100% effective LAA closure at 1 year
• Secondary endpoint of 2-year stroke/systemic embolism met at 3.4% vs 8.7% performance goal
Bottom Line
The WATCHMAN FLX device demonstrated favorable safety and efficacy through 2 years, meeting the prespecified secondary endpoint of ischemic stroke or systemic embolism at 3.4% with superior anatomic closure rates compared to the first-generation device.
Major Points
- Single-arm prospective trial of 400 enrolled patients across 29 US centers evaluating next-generation WATCHMAN FLX device
- Successfully implanted in 395 patients (98.8%) with 100% effective LAA closure at 1 year
- 2-year ischemic stroke/systemic embolism rate of 3.4% met performance goal of <8.7%
- No device embolizations, pericardial effusions, or device-related thrombi after 1 year
- 90% of patients had no detectable peridevice leak at 1 year, all residual leaks ≤3mm
Study Design
- Study Type
- Single-arm, prospective, nonrandomized trial
- Randomization
- No
- Blinding
- None - single-arm study
- Sample Size
- 400
- Follow-up
- 2 years
- Centers
- 29
- Countries
- United States
Primary Outcome
Definition: Primary safety endpoint: occurrence of death, ischemic stroke, systemic embolism, or device/procedure-related events requiring open cardiac surgery or major endovascular intervention within 7 days/discharge; Primary effectiveness endpoint: effective LAA closure (peridevice flow ≤5mm) at 12 months
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| Safety: 0.5% (2/400); Effectiveness: 100% (342/342) | - (Safety: 95% CI 1.6%; Effectiveness: lower 1-sided 95% CI 99.1%) | Safety: P<0.0001; Effectiveness: P<0.0001 |
Limitations & Criticisms
- Single-arm study design compared to performance goal rather than randomized control
- Patients required to take oral anticoagulation until LAA seal demonstration, limiting generalizability to patients with absolute contraindications to anticoagulation
- 4% delta for secondary efficacy endpoint contains element of arbitrariness
- Sample size may not be large enough to provide robust estimates of rare clinical events
- Observational design limits ability to definitively establish causal relationships
Citation
J Am Heart Assoc. 2023;12:e026295. DOI: 10.1161/JAHA.122.026295