What is the best way to evaluate Watchman (Left Atrial Appendage Closure Device) placement and leak in adult patients with atrial fibrillation and impaired renal function?

Evaluation of Watchman Device Placement and Leak

Transesophageal echocardiography (TEE) is the gold standard for evaluating Watchman device placement and peridevice leak, with mandatory surveillance at 45 days and 1 year post-implantation to assess for device-related thrombus and leak before discontinuing anticoagulation. 1

Primary Imaging Modality: TEE

TEE should be performed at two critical timepoints:

• 45 days post-implantation to evaluate device-related thrombus and peridevice leak before transitioning from warfarin to dual antiplatelet therapy 1, 2
• 1 year post-implantation for continued surveillance before transitioning to aspirin monotherapy 1, 2

Key TEE Assessment Parameters

Device positioning and stability must be evaluated to ensure proper placement and absence of device migration 1

Peridevice leak assessment requires systematic evaluation using multiple views:

• Mid-esophageal views at 0°, 45°, 90°, and 135° are essential to avoid missing leaks visible only in certain planes 1
• Any peridevice leak, regardless of size, is associated with increased risk of thromboembolism and requires continued anticoagulation 1, 2
• Color Doppler with optimized settings should be used throughout multiple cardiac cycles 1

Device-related thrombus detection requires assessment of:

• Distinct echodensity separate from device fabric 1
• Independent motion of mass relative to device movement 1
• Presence on multiple views throughout the cardiac cycle 1
• Device-related thrombus occurs in 1.7-7.2% of patients and significantly increases stroke risk (HR 4.6) 2

Complete LAA occlusion should be confirmed with color Doppler showing no flow inside the appendage 1

Complications screening must include systematic evaluation for:

• Pericardial effusion (even small effusions warrant close monitoring as they may indicate perforation) 1
• Left upper pulmonary vein obstruction 1
• Mitral valve impingement 1
• Air embolism 1

Technical Optimization of TEE

3D TEE provides superior assessment of device morphology, position, and relationship to surrounding structures with en face views from the left atrial perspective 1

Multiplane TEE with systematic sweeps through 0°, 45°, 90°, and 135° views is necessary to fully visualize all aspects of the device 1

Alternative Imaging: Cardiac CT Angiography

Cardiac CT angiography (CCTA) is a suitable alternative to TEE for device surveillance, particularly in patients unable to tolerate TEE or with contraindications 3

Advantages of CCTA Over TEE

CCTA is more sensitive than TEE for detecting peridevice leak:

• CCTA detected LAA patency in 52% of patients (86.5% via peridevice leak, 13.5% via fabric leak) 3
• TEE detected peridevice leak in only 34.3% of the same cohort 3
• CCTA can delineate the cause of residual LAA contrast patency 3

CCTA provides quantitative assessment:

• Linear attenuation coefficient <100 HU and LA:LAA ratio <0.25 indicate occluded devices 3
• Mean device compression can be accurately measured (greater compression associated with sealed devices: 11.3±4.3% vs 8.2±4.0%) 3

CCTA can identify minor lobes and trabeculations not apparent on TEE 4

Limitations of CCTA

Glomerular filtration rate <30 mL/min/1.73 m² is an exclusion for CCTA, making it particularly problematic in patients with impaired renal function 3

Radiation exposure is a consideration, though modern prospective cardiac-gated protocols minimize this risk 3

High-Risk Patients Requiring Enhanced Surveillance

Patients with the following characteristics have increased risk of device-related thrombus and warrant closer monitoring:

• Non-paroxysmal atrial fibrillation (OR 1.90-2.24) 1
• Renal insufficiency (OR 4.02) - particularly relevant for the patient population in question 1
• History of TIA or stroke (OR 2.31) 1, 5
• Deep device implantation >10 mm from pulmonary vein limbus (OR 2.41) 1

Extended surveillance beyond 1 year may be necessary in these high-risk patients, as device-related thrombus at 1 year occurred in patients without prior thrombus 5

Novel Imaging Approaches

CT-TEE fusion imaging can provide enhanced procedural guidance during Watchman implant and improved assessment for peridevice leak post-implant 4

Patient-specific computational modeling using preprocedural CCTA (FEops HEARTguide) accurately predicts device size, position, and compression, though this is primarily a planning tool rather than surveillance modality 6

Critical Clinical Pitfalls

The 45-day TEE is performed while patients are still on anticoagulation, making it unlikely to detect device-related thrombus that typically occurs after transitioning to antiplatelet therapy 7

Alternative surveillance strategy: Some centers delay first imaging to 4 months post-implantation (after transitioning to aspirin monotherapy) to capture the "vulnerable period" when device-related thrombus is most likely to occur 7

Patients with detected peridevice leak cannot safely discontinue warfarin at 45 days and require continued anticoagulation 2

Device-related thrombus incidence increases from 45 days (3.2%) to 1 year (5.6%), and new thrombus at 1 year occurs in patients without prior thrombus, emphasizing the importance of continued surveillance 5

Practical Algorithm for Patients with Impaired Renal Function

For patients with GFR ≥30 mL/min/1.73 m²:

• Use TEE as primary modality at 45 days and 1 year 1
• Consider CCTA if TEE is non-diagnostic or patient cannot tolerate TEE 3

For patients with GFR <30 mL/min/1.73 m²:

• TEE is the only option, as CCTA is contraindicated 3
• These patients are at higher risk for device-related thrombus (OR 4.02) and warrant particularly careful surveillance 1
• Consider extended surveillance beyond 1 year given high-risk status 5