Morphometric ablation lesion characteristics comparing 4, 6, and 8 mm electrode-tip cryocatheters

Area of Science:

• Cardiovascular Ablation Technologies
• Medical Device Characterization
• Electrophysiology

Background:

• Cryoablation is widely used clinically.
• Lesion characteristics of 6 and 8 mm cryocatheter tips require further definition.
• Quantifying lesion dimensions and thrombus formation is essential for understanding cryocatheter performance.

Purpose of the Study:

• To quantify and compare lesion dimensions created by 4, 6, and 8 mm electrode-tip cryocatheters.
• To assess thrombus formation in cryolesions produced by different cryocatheter sizes.
• To investigate the relationship between temperature and lesion characteristics.

Main Methods:

• A randomized factorial design was employed to create 72 ablation lesions in swine.
• Lesions were created using 4, 6, and 8 mm electrode-tip cryocatheters at a mean temperature of 79.9°C.
• Histological morphometric analysis was used to measure lesion depth, surface area, and volume.

Main Results:

• Cryolesions were well-circumscribed with intact endothelial layers and no thrombus.
• Colder temperatures correlated with larger lesion surface area and volume, but not depth.
• 8 mm catheters produced significantly larger surface areas and volumes compared to 4 mm and 6 mm catheters.
• Lesion depth was similar across all tested electrode-tip sizes.

Conclusions:

• Longer electrode-tip cryocatheters result in larger cryolesions of consistent depth.
• Intact endothelial layers and absence of thrombosis were observed across all tested sizes.
• Surface area and volume variability may be influenced by catheter tip-to-tissue contact angles, particularly with larger electrodes.