Importance of Compression Rate During Left Atrial Appendage Closure with Watchman FLX

Purpose: Left atrial appendage (LAA) closure is an option for patient with atrial fibrillation that cannot take oral anticoagulant due to high bleeding risk. Before release of device PASS (position, anchor, size and seal) criteria must be verified. Optimal compression rate for watchman FLX device is between 10-30% according to company recommendations. The study evaluates the correlation between compression rate and leak presence after left atrial appendage closure.

Material and Methods: This is a study including patients that underwent LAA closure under transesophageal echocardiography (TEE) with at least one follow-up where complete LAA closure was assessed by TEE in our center. All TEE images were reviewed by the first author. Compression rate was calculated based on intraprocedural TEE images using the following formula: (original device size—size after deployment)/original device size*100. Patients were divided into 2 groups based on the compression rate: group 1: 10-30%; group 2: >30%. The rate of leak between groups was compared using the Chi-square test.

Results: 83 patients (mean age: 77 ± 7 years) were included in the study. The implanted device size was 20 mm in 2 (2.4%), 24 mm in 11 (13.2%), 27 mm in 21 (25.3%), 31 mm in 32 (38.5%), and 35 mm in 17 (20.4%) patients.
Based on the compression rate, patients were classified into group 1: >30% [n=11 (13.2%)] and group 2: ≤30% [n=72 (86.7%)]. Mean compression rate was 37.1% and 20.78% in group 1 and 2 respectively. At follow-up TEE, 20 (24%) patients were found to have a residual leak of < 5 mm.
When comparing leaks between the two groups, there was no leak in patients with > 30% compression rate whereas in the group with ≤30% there were 20 leaks (0/11 vs 20/72, p value 0.04, RR 0, 95% CI, 0-1).

Conclusions: Devices with compression rate ≤30% were associated with significantly higher risk of residual leak.