Left atrial appendage closure checklist: clinical steps before the procedure

Those questions require a documented decision process, a review of stroke and bleeding risk, and cardiac imaging before the procedure.

The workup is not complete when a patient has atrial fibrillation and wants to avoid long-term anticoagulation. The team must establish the patient’s treatment history and preferences, assess the left atrial appendage (LAA), and confirm that there is no thrombus. Medication changes and fasting instructions depend on the treating center and the specific device. There is no single schedule that applies to every patient.

1. Establish the clinical indication and document the decision

Start with the reason LAAC is being considered. The clinical record should connect the patient’s non-valvular atrial fibrillation, stroke risk, bleeding risk, anticoagulation history, and preferences to the proposed intervention.

A risk score supports that assessment. It does not replace it. Under U.S. Medicare coverage criteria, the specified thresholds are CHADS2 of 2 or higher, or CHA2DS2-VASc of 3 or higher. These are coverage criteria, not universal clinical eligibility rules, and other insurers may use different policies.

The Medicare criteria also describe a patient who is suitable for short-term warfarin but considered unable to take long-term oral anticoagulation after shared decision-making. That distinction matters. LAAC does not remove the need to plan for antithrombotic treatment around and after implantation. The treating team must determine what is appropriate for the individual patient and device.

Before the procedure, Medicare coverage criteria call for a formal shared decision-making interaction. It must be documented and involve an independent, non-interventional physician. The discussion uses an evidence-based decision tool about oral anticoagulation for non-valvular atrial fibrillation.

A useful record makes the decision traceable. It should show:

• The patient’s stroke-risk assessment and the score used.
• The history of oral anticoagulant use, including adherence and any relevant difficulties.
• Bleeding risk, contraindications to anticoagulation, and other medical comorbidities.
• The patient’s preferences after discussion of the treatment options.
• The rationale for considering LAAC and the plan for short-term antithrombotic management.

Those elements also help distinguish a clinical decision from an assumption based on a single diagnosis or score. CMS protocols describe review of comorbidities, imaging, stroke and bleeding risks, anticoagulation history and adherence, structural heart factors, contraindications, and patient preferences.

A score establishes part of the risk profile. The documented decision explains why this patient is proceeding.

2. Review stroke risk, bleeding risk, and anticoagulant history together

The preprocedure assessment should put stroke risk and bleeding risk in the same clinical frame. A high stroke-risk score alone does not answer whether LAAC is appropriate. The team also needs to understand why long-term oral anticoagulation is considered unsuitable, what the patient has previously taken, and whether treatment was followed as prescribed.

Review the medication history with enough detail to support the plan. The record should capture current and previous anticoagulants, adherence, reported problems, and any documented contraindication. It should also include antiplatelet therapy and other medicines that may affect the peri-procedural plan. The available evidence does not establish one medication-hold schedule or anticoagulant-adjustment protocol for every patient.

That is why medication instructions must come from the treating team. Patients should not stop anticoagulants, antiplatelet drugs, or other prescribed medicines on their own. A change that seems straightforward on a medication list can alter the balance of stroke and bleeding risk.

The decision should also account for conditions that affect procedural planning or the feasibility of the post-implant regimen. Comorbidities belong in the assessment because they can change how imaging is obtained, what procedural risks need attention, and whether the planned antithrombotic strategy is workable.

A practical review can proceed in this order:

1. Confirm the atrial fibrillation context and record the stroke-risk score.

2. Assess bleeding risk and document relevant contraindications to anticoagulation.

3. Reconcile the anticoagulant and antiplatelet history, including adherence.

4. Review medical comorbidities and structural factors that may affect the procedure.

5. Record the patient’s preferences and the shared decision about long-term stroke prevention.

6. Confirm that the proposed short-term medication plan has been set by the treating team.

This sequence keeps the indication, anatomy, and treatment plan connected. It also exposes missing information before the patient reaches the catheterization laboratory.

3. Obtain baseline imaging and map the appendage

Cardiac imaging is central to LAAC planning. SCAI/HRS consensus guidance recommends baseline transesophageal echocardiography (TEE) or cardiac computed tomography (CCT). For procedural guidance, it recommends TEE or intracardiac echocardiography.

The baseline study must characterize the LAA well enough for the team to assess its size and shape, identify its lobes, and understand their position relative to the ostium. Imaging also needs to establish whether thrombus is present. A single measurement from one view is not a complete anatomical assessment.

For WATCHMAN FLX implantation, the device labeling calls for imaging in multiple views to assess the appendage’s size, shape, lobes, and relationship to the ostium, while confirming absence of thrombus. The label also notes that successful sizing depends on multiple imaging views and that hydration can affect LAA size.

That hydration point has a mechanical consequence. A measurement is only useful in the context in which it was obtained. The implanting team should interpret the study using the relevant device instructions and the imaging protocol at the treating center. A number copied from a report without its views, anatomy, or clinical context does not establish device fit.

TEE and CCT are both recognized baseline options in the consensus guidance. The selection depends on the clinical situation and the team’s imaging approach. TEE is also one recommended method for guidance during the procedure; intracardiac echocardiography is another. The fact that a center uses one modality does not make it the only acceptable method in every case.

The preprocedure imaging review should answer specific questions:

• Is the appendage anatomy adequately visualized?
• What are the ostium dimensions across the required views?
• How many lobes are identified, and how are they oriented?
• Is there thrombus in the appendage or another relevant intracardiac finding?
• Does the anatomy fall within the labeling for the specific device being considered?
• Is the imaging suitable for procedural guidance under the center’s plan?

If the study cannot answer those questions, device selection remains unresolved. The next step is to discuss whether additional or different imaging is needed with the treating team. The evidence reviewed here does not prescribe one universal pathway for every incomplete or ambiguous scan.

4. Exclude thrombus before proceeding to device sizing

Thrombus assessment is a gate in the workup. WATCHMAN FLX labeling calls for confirmation that thrombus is absent as part of the imaging assessment. Device sizing should not be treated as a substitute for that finding.

The imaging report and procedural plan need to make the result clear. If thrombus is identified, or if the study does not adequately establish its absence, the team must resolve that issue before proceeding according to the device instructions and clinical judgment. The sources summarized here do not define a single management pathway for every such finding, so the patient-specific plan belongs with the treating clinicians.

This is also why baseline imaging is more than a measurement exercise. It checks whether the target is suitable for the intended intervention and whether the procedure can be planned from adequate anatomical information. A technically precise ostium measurement has limited value if the rest of the appendage has not been assessed or thrombus status is uncertain.

The preprocedure record should link the imaging result to the planned device and the decision to proceed. That connection makes it possible to see which study informed the plan and whether the required anatomical and thrombus checks were completed.

5. Match ostium dimensions to the selected device

Device selection begins with the anatomy and the labeling for the particular device. For WATCHMAN FLX, the labeled maximum LAA ostium width across available device sizes is 14.0 to 31.5 mm. That range is specific to WATCHMAN FLX. It should not be applied to every LAAC device.

The range is not a stand-alone pass/fail measurement. The device labeling emphasizes multiple imaging views, assessment of appendage shape and lobes, and the relationship between the lobes and the ostium. Hydration can affect measured LAA size. The implanting team therefore needs to interpret dimensions within the full imaging set and the device’s instructions.

A disciplined sizing review follows this order:

1. Confirm that the baseline TEE or CCT adequately depicts the LAA.

2. Review measurements across multiple views rather than relying on one dimension.

3. Assess the appendage’s shape, lobes, and their position relative to the ostium.

4. Confirm that thrombus is absent.

5. Compare the anatomy with the labeling for the specific device under consideration.

6. Resolve any mismatch or uncertainty before the procedure.

The last step matters. If the anatomy does not fit the selected device’s labeling, or the views do not support a reliable assessment, the plan needs further review. The correct response is not to stretch a device-specific range into a universal rule.

6. Close the loop on instructions and readiness

The final preprocedure check is operational. The team should confirm that the patient has received instructions from the treating center, that the medication plan has been reviewed, and that fasting requirements are clear.

There is no universal fasting instruction established by the evidence summarized here. Medication changes are also not governed by one schedule that applies to every patient and device. These instructions depend on the center’s protocol, the procedure plan, the patient’s clinical details, and the specific device labeling.

The FDA patient-facing information for WATCHMAN FLX describes a care-team review of medical history and stroke risk, a physical examination, and heart imaging. It advises patients to discuss medication changes with their doctor rather than making changes independently. That is the appropriate operational rule: use the instructions issued by the treating team, and clarify anything that conflicts with the current medication list or procedure date.

Before the procedure date, the record should show a completed clinical decision, an imaging-based anatomical assessment, thrombus status, device-specific sizing review, and a patient-specific medication and fasting plan. If one of those items is missing, readiness has not been established.

The decision point

A complete left atrial appendage closure patient checklist has two endpoints. The first is clinical: the indication, risk profile, anticoagulation history, and shared decision are documented. The second is mechanical: baseline imaging defines the appendage, thrombus is absent, and the anatomy fits the selected device’s labeling.

Proceed when both endpoints are supported by the record and the treating team has issued clear instructions. If either remains uncertain, pause for resolution before deployment.