4D Volume Intracardiac Echocardiography for Intraprocedural Guidance of Transcatheter Left Atrial Appendage Closure

Abstract

Background: Fluoroscopy and transesophageal echocardiography (TEE) are used to guide transcatheter left atrial appendage (LAA) closure in patients with atrial fibrillation to prevent thromboembolic events. This study examines whether real-time three-dimensional volume ICE guidance (4D volume ICE) can be used as an alternative to TEE during LAA closure (LAAC).

Methods and results: Fifteen patients with atrial fibrillation (AF), who had high risk for stroke and contraindication for long-term warfarin therapy, were enrolled in the study. The WATCHMAN device was used for transcatheter LAAC under fluoroscopy. LAA and device sizing was performed using TEE and volume ICE guidance from the right heart. Intraprocedural ICE measurements were consistent with TEE; LAA maximal width and depth, and maximal diameter of the implanted device were moderately correlated (Pearson's coefficient: 0.63, 0.65, and 0.71 respectively; p<0.05) with good agreement (bias: -0.03 cm, -0.07 cm, and 0.003 cm respectively). The average imaging success rate, defined by the number of patients with all the required intraprocedural measurements, was 67% for ICE and 100% for TEE. The WATCHMAN device was successfully implanted in all patients with a device to patient ratio of 1.33.

Conclusions: 4D volume ICE can be used as an intraprocedural sizing and guidance tool for transcatheter LAAC with measurements comparable to TEE. Challenging patient characteristics significantly degrade the diagnostic image quality when imaging from the right heart. Standardized workflow with proper patient selection and optimal preprocedural planning may improve the diagnostic quality of volume ICE guidance for transcatheter LAAC procedure.

Keywords: ICE; LAA Closure; TEE; WATCHMAN.

Figures

Figure 1.. Device selection criteria for LAA closure. The physical device size is defined as the maximum "shoulder-to-shoulder" diameter of the device and is selected using the manufacturer's guidelines based on the LAA ostium width measured on TEE, ICE or angiogram (left illustration with permission from Boston Scientific). Post deployment, adequate compression of the device is measured.

Figure 2A.. LAAC workflow illustration using 4D Volume ICE guidance. The ICE catheter is introduced via a femoral venous access into the right atrium (RA). Under echo guidance, a Baylis wire is used for interatrial transseptal puncture for delivery of the occluder device into the LAA under fluoroscopy (right illustration with permission from Boston Scientific).

Figure 2B. Home View. With the ICE catheter positioned in the right atrium, the anatomical landmarks are visualized to establish spatial orientation (see Supplemental Video 1): a Home View consists of the right atrium (RA), the tricuspid valve (TV), and the right ventricle (RV). The catheter probe is swept to assess for any contraindications in this view and orthogonal multiplanar reformatted (MPR) planes.

Figure 2C.. Transseptal Puncture. ICE from the right heart is used to visualize the interatrial septum (IAS) to guide the Baylis wire for a transseptal puncture. 4D ICE MPR and en face views can be used for TSP guidance (see Supplemental Video 2).

Figure 2D.. Device Deployment. Under fluoroscopy, the WATCHMAN LAA occluder device is deployed via a delivery sheath which can be visualized under ICE (See Supplemental Video 3) and TEE. The compression measurement of the occluder is taken on multiple views to determine adequate device positioning and seal following the manufacturer's guidelines for device release.

Figure 3.. LAA Sizing. LAA orifice width and depth are measured on multiple views on both TEE and ICE using planar (A and B; SAX: short axis, and LAX: long axis) and non-planar (C and D) views, to determine the maximal LAA sizing for device selection per the manufacturer's guidelines.

Figure 4.. Compression Measurement. The device release criteria is followed to ensure adequate positioning, anchoring, sizing, and seal. Compression measurements are taken on both TEE (A) and ICE (B) to determine the adequate compression rate. Tug test is performed for adequate anchoring prior to device release, and Color Doppler flow is used to assess for peri-device leak (C and D; see Supplemental Video 3).

Figure 5.. Correlation and Agreement Analysis. TEE and ICE measurements of LAA maximal width and depth, and the device maximal diameter (A) were moderately correlated with good agreement (B, C and D respectively); r = Pearson's correlation coefficient; SD = Standard deviation; 2SD was used to calculated the 95% limits of agreement.

Figure 6.. Procedural Characteristics. On average, the procedure duration (white) and the diagnostic fluoroscopy duration (stacked striped) were randomly distributed and comparable to reported values.