Toward a computationally efficient numerical approach to simulate the left atrial appendage occlusion in patient-specific anatomies

Q: What is the clinical evidence from this study?

Population: Atrial fibrillation (Left atrial appendage occlusion) (n=3). Intervention: Simplified Watchman FLX finite element models (No Fabric Model and Bare Frame Model) vs. Detailed Watchman FLX model (Complete Model). Primary outcome: LAA sealing (gap classification), device protrusion into the LA, intrusion into the LAA, and CPU time.

Q: What does this research mean for the field?

Omitting the fabric membrane in finite element simulations of left atrial appendage occlusion substantially reduces computation time while preserving predictive accuracy for device sealing and positioning, whereas omitting anchoring hooks leads to unacceptable errors. Novelty: ClaimNovelty.METHODOLOGICAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Chiara Bonfanti; Francesca Danielli; Francesca Berti; Benigno Marco Fanni; Emanuele Gasparotti; Simona Celi; Sergio Berti; Giancarlo Pennati; Lorenza Petrini

doi:10.1016/j.cmpb.2026.109652

September 18, 2026Computer Methods and Programs in BiomedicineOpen Access

Toward a computationally efficient numerical approach to simulate the left atrial appendage occlusion in patient-specific anatomies

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Why the study?

Device selection and positioning for left atrial appendage occlusion remain challenging due to complex patient-specific anatomy and uncertain wall mechanics, requiring accurate and efficient simulations.

Does simplifying the Watchman FLX finite element model reduce computational runtime while preserving accuracy in predicting LAA sealing and positioning?

Key Points

Evaluate simplified finite element models of the Watchman FLX device in patient-specific left atrial appendage geometries to reduce computational runtime without compromising clinical predictive accuracy.
Implemented three Watchman FLX models in Abaqus/Explicit: a Complete Model (CM), a No Fabric Model (NFM) omitting the proximal membrane, and a Bare Frame Model (BFM) lacking fabric and anchoring hooks.
Reconstructed three patient-specific left atrial appendage anatomies from CT and simulated 12 clinical scenarios (optimal vs. suboptimal catheter positioning across low vs. high wall stiffness), yielding 36 total simulations.
Evaluated procedural outcomes including left atrial appendage sealing gap classification, device protrusion, intrusion depth, and CPU runtime.
The NFM reproduced CM gap classifications in all 12 scenarios and predicted protrusion and intrusion within ±1 mm in 10 of 12 scenarios, reducing average runtime from 5.6 hours to 3.8 hours.
The BFM demonstrated unstable deployment in 2 of 12 scenarios and mispredicted sealing gaps and protrusion, despite achieving the lowest average runtime (3.2 hours).
Procedural outcomes strongly depended on catheter positioning and wall stiffness even with fixed device sizing, with successful sealing achieved in at least one scenario per anatomy.

Structured PICO

Does simplifying the Watchman FLX finite element model reduce computational runtime while preserving accuracy in predicting LAA sealing and positioning?

P

Population

3 patient-specific LA-LAA anatomies reconstructed from CT used to evaluate finite element simulation models for Watchman FLX deployment across 12 scenarios.

E

Exposure

Simplified finite element models of Watchman FLX (No Fabric Model [NFM] omitting proximal fabric membrane, and Bare Frame Model [BFM] excluding fabric and anchoring hooks).

C

Comparator

Detailed Watchman FLX finite element model (Complete Model [CM]).

O

Outcome

LAA sealing (gap classification), device protrusion into the LA, intrusion into the LAA, and CPU time.surrogate

Omitting the proximal fabric membrane in finite element simulations of Watchman FLX deployment reduces computational time while maintaining accuracy, potentially supporting efficient pre-interventional LAAO planning.

Implication

Patient-specific FE models may aid LAAO planning; leaves open whether they improve procedural outcomes or require prospective validation.

Abstract

BACKGROUND AND OBJECTIVES: Left atrial appendage occlusion (LAAO) is increasingly used to prevent stroke in atrial fibrillation, but device selection and positioning remain challenging due to complex, patient-specific anatomy and uncertain wall mechanics. Finite element (FE) simulations could support pre-interventional planning, provided they are both accurate and computationally efficient. This study extends a previously validated Watchman FLX FE model to patient-specific anatomies and evaluates model simplifications to reduce runtime without compromising clinically relevant predictions. METHODS: A detailed Watchman FLX model (Complete Model, CM) and two simplified variants (No Fabric Model, NFM, in which the proximal fabric membrane is omitted; Bare Frame Model, BFM, consisting solely of the metallic frame and excluding both the fabric and the anchoring hooks) were implemented in Abaqus/Explicit. Three patient-specific LA-LAA anatomies were reconstructed from CT. For each anatomy, four scenarios were simulated (optimal/suboptimal catheter positioning × low/high wall stiffness), for a total of 12 scenarios and 36 simulations. Deployment, anchoring and release were modeled. Outcomes included LAA sealing (gap classification), device protrusion into the LA, intrusion into the LAA, and CPU time. RESULTS: With the CM, procedural outcome strongly depended on positioning and wall stiffness, even for a fixed device size. For all anatomies, at least one scenario achieved complete sealing and acceptable alignment. The NFM reproduced CM gap classification in all cases and intrusion/protrusion within ±1 mm in 10/12 scenarios, correctly identifying poor outcomes in the remaining two. The BFM showed unstable deployment in 2/12 scenarios and mispredicted gaps and protrusion in others. Average runtimes were 5.6 h (CM), 3.8 h (NFM), and 3.2 h (BFM). CONCLUSIONS: The proposed pipeline enables scenario-based, patient-specific LAAO simulation. Neglecting the fabric (NFM) substantially reduces computational cost while preserving accuracy, whereas neglecting hooks (BFM) is not acceptable.

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Cite This Study

Bonfanti et al. (2026) studied Atrial fibrillation (Left atrial appendage occlusion) (n=3). Simplified Watchman FLX finite element models (No Fabric Model and Bare Frame Model) vs. Detailed Watchman FLX model (Complete Model) was evaluated on LAA sealing (gap classification), device protrusion into the LA, intrusion into the LAA, and CPU time.

synapsesocial.com/papers/6ad0fd3315427f6a84040581 https://doi.org/10.1016/j.cmpb.2026.109652