Related Experiment Video
Updated: Dec 17, 2025
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Detailed thrombogenicity phenotyping and 1 year outcomes in patients undergoing WATCHMAN implantation:
Matthew Sherwood1, Kevin P Bliden2, Leonard Ilkhanoff1
1Inova Center for Thrombosis Research and Drug Development, Inova Heart and Vascular Institute, Fairfax, VA, USA.
Insights
Device-related thrombosis after left atrial appendage closure (LAAC) is linked to a prothrombotic profile. Bleeding complications are associated with low platelet reactivity, suggesting tailored antithrombotic strategies.
Area of Science:
- Cardiology
- Thrombosis Research
- Medical Devices
Background:
- Left atrial appendage closure (LAAC) is an alternative to anticoagulation for stroke prevention in atrial fibrillation.
- The relationship between laboratory hemostasis markers and adverse events like device-related thrombosis (DRT) and major bleeding post-LAAC remains understudied.
- Understanding these relationships can optimize patient selection and antithrombotic therapy.
Purpose of the Study:
- To investigate the association between laboratory thrombosis and hemostasis markers and the occurrence of DRT and major bleeding following WATCHMAN LAAC.
- To identify clinical characteristics and laboratory profiles of patients experiencing these adverse events.
Main Methods:
- Prospective case-control study involving 32 patients undergoing WATCHMAN LAAC.
- Laboratory markers including thromboelastography, platelet aggregation, D-dimer, and fibrinogen were measured at multiple time points.
- Clinical outcomes (DRT, BARC bleeding) were followed for one year.
Main Results:
- Patients who developed DRT showed higher baseline thrombin-induced platelet-fibrin clot strength and D-dimer levels.
- A prothrombotic baseline profile was associated with DRT, while low platelet reactivity correlated with major bleeding (Type 3A BARC).
- Five patients with three high-risk thrombotic factors experienced DRT within six months.
Conclusions:
- DRT after LAAC is associated with a prothrombotic state at baseline.
- Major bleeding post-LAAC is linked to reduced platelet reactivity.
- These findings may inform future patient selection and personalized antithrombotic treatment strategies.
Abstract:
The relation of device related thrombosis (DRT) and major bleeding after left atrial appendage closure (LAAC) to laboratory thrombosis and hemostasis markers has not been studied. We performed a prospective case control study to identify clinical characteristics and laboratory markers in patients who developed DRT and major bleeding following WATCHMAN LAAC. Thromboelastography, platelet aggregation (PA), urinary 11-dehydrothromboxane B2 (UTX), fibrinogen, D-dimer, thrombin time and von Willebrand factor activity were determined at baseline, immediately following, and at 45 and 180 days post-LAAC (n = 32) and outcomes were followed for 1 year. Baseline characteristics and thrombogenic profiles of patients with and without DRT and/or BARC bleeding were compared. Mean age was 76 ± 8 years and CHADS2 VASc score was 4.4 ± 1.4. There were 3 DRTs (2 within 6 months, and 1 at 12 months), 4 Type 3A BARC bleeds, and 2 non-cardiac deaths. Patients with DRT had higher baseline thrombin-induced platelet-fibrin clot strength (68.0 ± 1.8 vs. 62.7 ± 4.7 mm, p = 0.06); FCS (35.6 ± 6.0 vs. 24.4 ± 6.6 mm, p = 0.009); and D-dimer (1712 ± 2330 vs. 283 ± 213 ng/mL, p = 0.001). At baseline, 5 patients had all 3 factors associated with high thrombotic risk and 2 experienced a DRT within 6 months. Patients with Type 3A BARC bleeding had lower baseline collagen-induced and 45-day ADP-induced PA (p < 0.01 for both). DRT following LAAC was associated with a baseline prothrombogenic profile whereas bleeding was associated with low platelet reactivity. These preliminary findings warrant further validation and have future implications on patient selection and adjunctive antithrombotic therapy following LAAC.Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03040622 .
