Is Plavix (Clopidogrel) Normal After Watchman?
Yes, Plavix (clopidogrel) is a standard component of the post-Watchman anticoagulation protocol, typically used in combination with aspirin from 45 days to 6 months after device implantation, following an initial 45-day period of warfarin plus aspirin. 1
Standard Post-Watchman Anticoagulation Protocol
The established regimen follows a three-phase approach:
Phase 1: Days 0-45
- Warfarin (INR 2.0-3.0) plus aspirin (81-162 mg daily) 1, 2
- A transesophageal echocardiogram (TEE) must be performed at 45 days to evaluate for device-related thrombus and peridevice leak before transitioning therapy 1
Phase 2: Days 45 to 6 Months
- Dual antiplatelet therapy with aspirin plus clopidogrel 75 mg daily 1, 2
- This transition occurs only if the 45-day TEE shows minimal peridevice leak (≤5mm) and no device-related thrombus 2
Phase 3: After 6 Months
Evidence Supporting This Regimen
This protocol was established in the PROTECT-AF and PREVAIL trials, which demonstrated that the Watchman device is non-inferior to warfarin for preventing stroke, systemic embolism, and cardiovascular death 1. The hemorrhagic stroke risk is significantly lower with Watchman compared to long-term warfarin (RR 0.09; 95% CI 0-0.45) 1.
Alternative Regimens for High Bleeding Risk Patients
For patients with absolute contraindications to oral anticoagulation, dual antiplatelet therapy (aspirin plus clopidogrel) for 6 months followed by aspirin indefinitely may be feasible, though this carries higher risk of device-related thrombus. 2, 3
A propensity-matched analysis found that while antiplatelet therapy alone resulted in similar overall safety and efficacy endpoints compared to the standard warfarin-based protocol, device-related thrombosis was significantly more common with antiplatelet therapy alone (3.1% vs 1.4%, p=0.018) 3.
Critical Caveats and Pitfalls
Clopidogrel Non-Responders
- Approximately 25-30% of patients may be clopidogrel non-responders, which increases the risk of device-related thrombus and thromboembolic events 4
- Consider platelet function testing in patients who develop device-related thrombus despite appropriate antiplatelet therapy 4
Risk Factors for Device-Related Thrombus
Monitor closely for these high-risk features:
- Non-paroxysmal atrial fibrillation (OR 1.90-2.24) 1
- Renal insufficiency (OR 4.02) 1
- History of TIA or stroke (OR 2.31) 1
- Deep device implantation >10mm from pulmonary vein limbus (OR 2.41) 1
TEE Surveillance is Mandatory
- Any peridevice leak detected by TEE, regardless of size, is associated with increased risk of thromboembolism 1
- High-grade hypoattenuated thickening (device-related thrombus) significantly increases stroke risk (HR 4.6) 1
- Do not discontinue warfarin at 45 days without confirming adequate device position and absence of thrombus on TEE 1, 2
When to Deviate from Standard Protocol
If Device-Related Thrombus Develops
- Switch from dual antiplatelet therapy to a DOAC (such as apixaban) for 3 months, then reassess with TEE 5
- Case reports demonstrate successful thrombus resolution with apixaban therapy 5
If Patient Cannot Tolerate Warfarin
- DOACs may be used as an alternative to warfarin in the initial 45-day period, though this is off-label and has limited evidence 2
- The standard protocol was designed around warfarin, and FDA approval specifies patients must be suitable for at least 45 days of warfarin 1
Important Clinical Context
The Watchman device was studied against warfarin, not modern DOACs, which have similar bleeding rates to aspirin—this makes the device's role in current practice less clear for patients who can tolerate DOACs. 1 The device is most appropriate for patients with genuine contraindications to long-term anticoagulation 1.