A comparative study of different imaging modalities for successful percutaneous left atrial appendage closure

Abstract

Objectives: Accurate sizing of the left atrial appendage (LAA) is essential when performing percutaneous LAA closure. This study aimed to compare different LAA imaging modalities and sizing methods in order to obtain successful LAA closure.

Background: Percutaneous LAA closure is an increasingly used treatment strategy to prevent stroke in patients with atrial fibrillation. LAA sizing has typically been done by 2D-transoesophageal echocardiography (TEE).

Methods: Patients who had a preprocedural TEE and preprocedural and postprocedural multislice CT (MSCT) were identified. Preprocedural measurements of LAA ostia and landing zones by 2D-TEE, MSCT and angiography were collected and analysed for those patients with successful LAA closure - i.e. with no contrast leakage at 3-month follow-up MSCT.

Results: The study population (n=67) had a mean CHA2DS2-VASc score of 3.0 and HAS-BLED score of 2.7. Fifty-eight patients (87%) were identified to have successful LAA closure. Based on MSCT, 48 LAA sizings (83%) resulted in a correct LAA closure device size selection, whereas with 2D-TEE sizing, only 33 measurements (57%) would have resulted in a correct device size selection (p<0.01). Using adapted Bland-Altman method, MSCT-based perimeter-derived mean diameter was shown to be the best parameter to guide LAA device size selection for ‘closed-end’ devices (Amulet, WatchmanFLX), whereas the maximal diameter was the best parameter for the ‘open-end’ Watchman device.

Conclusions: Preprocedural MSCT-based LAA closure device size selection proves to be a more accurate method than conventional 2D-TEE-based sizing. Depending on the LAA closure device design, perimeter-derived mean diameter or maximal diameter could be the better sizing method.

Keywords: ATRIAL FIBRILLATION; DEVICE CLOSURE; STROKE.

Conflict of interest statement

Competing interests: None declared.

Figures

Figure 1

Flow chart. Flow chart showing the number of patients with successful percutaneous LAA closure based on the evaluation of the 3-month CT follow-up. LAA, left atrial appendage; MSCT, multislice CT; TEE, transoesophageal echocardiography.

Figure 2

Postprocedural multislice CT (MSCT) follow-up. MSCT control scans at 3 months postprocedure to assess LAA device position and complete LAA closure. (A) Successful LAA closure with an Amulet occluder with no contrast leakage into LAA. (B) Unsuccessful LAA closure with contrast leakage into LAA due to Amulet device undercompression. (C) Unsuccessful LAA closure with contrast leakage into LAA due to Amulet device overcompression. (D) Successful LAA closure with a Watchman LAA closure device with no contrast leakage into LAA. (E) Successful LAA closure with a WatchmanFLX LAA closure device with no contrast leakage into LAA. (F) Unsuccessful LAA closure with contrast leakage into LAA due to a rotated, non-occlusive WatchmanFLX closure device. LAA, left atrial appendage.

Figure 3

LAA device compression and LAA leakage. Correlation between LAA closure device compression rate (%, as assessed on angiography postimplantation) and incidence of LAA leakage as observed at 3 months multislice CT follow-up. In case of 10%–20% device compression, successful LAA closure was obtained in 37 out of 38 cases (97%); leakage into the LAA was more frequently observed in case of LAA device undercompression or overcompression. LAA, left atrial appendage.

Figure 4

LAA sizing by different imaging modalities. The calculated mean difference between LAA sizing and final LAA closure device size for the different LAA closure devices and imaging modalities. This analysis only included successful percutaneous LAA closures (n=58). Adapted Bland-Altman method was used to calculate the mean difference, 95% limits of agreement and Δ limits of agreement. LAA, left atrial appendage; TEE, transoesophageal echocardiography.

Figure 5

Bland-Altman plots. The adapted Bland-Altman plots for 2D-TEE and optimal CT-guided LAA closure device sizing. This analysis only included successful percutaneous LAA closures (n=58). The plots show the difference between LAA sizing and final LAA closure device size for the different LAA closure devices and imaging modalities. Considering the official TEE-recommended sizing versus CT-based recommendation to select the first-available larger LAA device size (‘one step up’), the number of correct sizings per device and imaging modality could be calculated. LAA, left atrial appendage; TEE, transoesophageal echocardiography.

Figure 6

Challenges with 2D-TEE-based LAA sizing. (A) The disadvantage of 2D-TEE-guided sizing despite the use of multiple angles for assessment of maximal LAA diameter. (B) 3D MPR assessment from MSCT allows accurate measurement of the perimeter-derived mean diameter and maximal LAA diameter. LAA, left atrial appendage; MSCT, multislice CT; TEE, transoesophageal echocardiography.

Figure 7

Device-specific CT-based LAA occluder size selection. Preprocedural cross-sectional CT assessment of the LAA landing zone. Since the cross section of the LAA landing zone is more often an ellipse, the major axis (maximal diameter) and minor axis (minimal diameter) may differ. As the device comes first into contact with the short axis of the LAA during deployment, there will be a compressive force onto the device. Depending on the design of the closure device, the device will expand or not in a perpendicular plane to the short axis in case of a ‘closed distal end’ or ‘open distal end’ LAA closure device, respectively. LAA, left atrial appendage.