Do patients with a Watchman (Left Atrial Appendage Closure) device still require Deep Vein Thrombosis (DVT) prophylaxis in the inpatient setting?

DVT Prophylaxis in Patients with Watchman Devices

Yes, patients with a Watchman device still require standard DVT prophylaxis during hospitalization based on their individual VTE risk assessment, as the Watchman device addresses stroke prevention from atrial fibrillation but does not protect against venous thromboembolism in the lower extremities.

Key Distinction: Arterial vs Venous Thrombosis

The Watchman device is designed specifically for left atrial appendage closure to prevent cardioembolic stroke in patients with atrial fibrillation 1, 2. This addresses arterial thromboembolism originating from the left atrium, which is an entirely different pathophysiologic process than DVT formation in the deep veins of the lower extremities 1.

• DVT prophylaxis targets venous stasis and hypercoagulability in hospitalized patients with reduced mobility, surgery, or acute illness 3
• The Watchman device does not alter venous thrombosis risk factors such as immobility, critical illness, or surgical procedures 2

Standard VTE Risk Assessment Still Applies

All hospitalized patients, including those with Watchman devices, require assessment of VTE risk prior to determining prophylaxis needs 3. The American Society of Hematology 2018 guidelines provide clear recommendations:

For Acutely Ill Medical Patients:

• Use LMWH or UFH for pharmacologic prophylaxis in patients at risk for VTE 3
• The ASH guideline panel recommends using LMWH over UFH (conditional recommendation, moderate certainty) 3
• Pharmacologic prophylaxis is preferred over mechanical prophylaxis alone 3

For Critically Ill Patients:

• Strong recommendation for UFH or LMWH over no prophylaxis (moderate certainty in evidence) 3
• LMWH is suggested over UFH in this population 3

Anticoagulation Considerations Post-Watchman Implantation

The anticoagulation regimen following Watchman implantation is specifically for device-related thrombosis prevention, not DVT prophylaxis 1, 2. The standard post-implantation protocol includes:

• Warfarin plus aspirin for 45 days post-implantation 1
• If TEE shows adequate device positioning with minimal peri-device flow (≤5mm) and no device-related thrombus, warfarin is discontinued 1
• Dual antiplatelet therapy (aspirin and clopidogrel) for 6 months, then aspirin indefinitely 1, 2

Critical Point on Bleeding Risk

Patients with Watchman devices often have contraindications to long-term anticoagulation due to high bleeding risk 1, 2. This creates a clinical challenge when DVT prophylaxis is needed:

• The presence of antiplatelet therapy does not eliminate the need for DVT prophylaxis in high-risk hospitalized patients 3
• However, bleeding risk must be carefully weighed when adding pharmacologic VTE prophylaxis to existing antiplatelet regimens 4

Practical Algorithm for DVT Prophylaxis Decision-Making

Step 1: Assess VTE Risk

Evaluate standard risk factors regardless of Watchman device presence 3:

• Immobility or critical illness 3, 5
• ICU admission 5
• Central venous catheter 5
• Leukocytosis >13,000/mm³ 5
• Cranial surgery or major procedures 5

Step 2: Assess Bleeding Risk

Consider the patient's current antithrombotic regimen post-Watchman 1:

• If within 45 days of implantation: Patient is likely on warfarin plus aspirin—use mechanical prophylaxis only (pneumatic compression devices or graduated compression stockings) 3
• If 45 days to 6 months post-implantation: Patient is on dual antiplatelet therapy—consider mechanical prophylaxis as first-line, reserve pharmacologic prophylaxis for very high VTE risk 3
• If >6 months post-implantation: Patient is on aspirin alone—standard pharmacologic prophylaxis can be used with LMWH or UFH 3

Step 3: Select Prophylaxis Method

For patients with high bleeding risk (on warfarin or dual antiplatelet therapy):

• Mechanical prophylaxis with intermittent pneumatic compression devices is recommended 3
• Ensure proper application and continuous use 3
• Early ambulation when feasible 3

For patients with moderate bleeding risk (on aspirin alone) and high VTE risk:

• LMWH is preferred over UFH (conditional recommendation) 3
• Standard prophylactic dosing: enoxaparin 40 mg daily or dalteparin 5000 IU daily 3

For patients who cannot receive pharmacologic prophylaxis:

• Mechanical prophylaxis is suggested over no prophylaxis (conditional recommendation, moderate certainty) 3

Common Pitfalls to Avoid

• Do not assume the Watchman device provides any DVT protection—it only addresses left atrial appendage thrombus formation 1, 2
• Do not withhold DVT prophylaxis solely because the patient has a Watchman device—assess VTE risk independently 3
• Do not automatically add pharmacologic DVT prophylaxis to warfarin in the first 45 days post-implantation without carefully considering bleeding risk 1
• Do not use graduated compression stockings in patients with peripheral arterial disease or skin breakdown 3
• Do not forget that mechanical prophylaxis requires proper fitting and continuous application to be effective 3

Special Considerations for Device-Related Thrombosis

If device-related thrombus is detected on surveillance TEE, this requires therapeutic anticoagulation (not prophylactic dosing) 6, 2:

• LMWH or oral anticoagulation (warfarin or DOACs like apixaban) are used for treatment 6, 2
• This is separate from the decision regarding DVT prophylaxis 2

Duration of Prophylaxis

Inpatient prophylaxis only is recommended for most hospitalized medical patients 3:

• The ASH guidelines recommend against extended-duration outpatient VTE prophylaxis in most acutely ill medical patients (strong recommendation) 3
• Continue prophylaxis throughout the hospitalization period while VTE risk factors persist 3