Foam-based Left Atrial Appendage Closure (CLAAS) Device: Evaluation in a Chronic Canine Model.

Area of Science:

• Cardiovascular Devices
• Biomaterials Science
• Medical Device Engineering

Background:

• The Conformal Left Atrial Appendage System (CLAAS) is a transcatheter implant designed for left atrial appendage occlusion.
• It aims to prevent stroke in patients with nonvalvular atrial fibrillation.
• The implant features a novel polyurethane polycarbonate-urea foam matrix for enhanced performance.

Purpose of the Study:

• To characterize the thrombogenicity, sealing efficacy, and implant integrity of the CLAAS device.
• To evaluate local tissue response and systemic toxicity in a canine model.
• To assess the long-term performance of the CLAAS implant up to 150 days.

Main Methods:

• The CLAAS implant was evaluated in a chronic canine model (n=8) using echocardiographic and fluoroscopic guidance.
• Postprocedural echocardiographic assessments were conducted at multiple time points up to 150 days.
• Necropsy, including gross, x-ray, and histologic examination, was performed at 90 and 150 days.

Main Results:

• Successful implantation was achieved in all animals, with complete sealing of the left atrial appendages observed on gross examination.
• Minor leaks (<5 mm) were noted in two animals, one at implantation and one at day 90.
• No device-related thrombus, pericardial effusion, distal organ emboli, or histologic evidence of toxicity was observed.

Conclusions:

• The CLAAS implant demonstrates successful deployment and effective sealing of the left atrial appendage in a canine model for up to 150 days.
• The device maintained structural integrity and showed good tissue integration.
• No local or systemic toxicity was observed, supporting its potential for clinical use in stroke prevention.