Evaluation of deployment capability of a novel outside-the-scope, detachable catheter system for ablation of lung lesions in ex vivo human lung models.

Objectives: Effective transbronchial ablation of lung nodules requires precise catheter delivery to the target lesion and freedom from the bronchoscope for safety throughout the procedure and to allow for multiple catheter insertions. A fully detachable, outside-the-scope (OTS) probe system was developed that attaches to a flexible bronchoscope. Using this system, the operator can deploy the probe in the target and completely detach it from the scope. Our aim was to demonstrate the endobronchial deployment accuracy and feasibility of an OTS, detachable, simulated ablation catheter driven to peripheral lung targets in ex vivo-ventilated human lung models. Methods: A balloon catheter inflated with radiopaque contrast was used as a simulated peripheral target in freshly explanted lungs from lung transplant recipients. A simulated ablation catheter was positioned outside and aligned to the tip of the bronchoscope using the OTS system. Under fluoroscopic guidance, the bronchoscope and the catheter were driven toward the target in mechanically ventilated lungs. Once the catheter tip was confirmed within the target, the OTS system was released and the probe was detached from the scope. The bronchoscope was retracted and fluoroscopy was used to confirm the position of the catheter. Results: Twelve peripheral targets were simulated. The ablation catheter was successfully deployed with its tip positioned within 5 mm from the target and confirmed stability during multiple cycles of ventilation. Conclusions: A novel, detachable, OTS system can be successfully deployed in peripheral lung targets with potential clinical applications for multiple procedures in advanced bronchoscopy where scope freedom is advantageous.

Cryoablation of the pulmonary veins using a novel balloon catheter.

INTRODUCTION: Pulmonary vein (PV) isolation has emerged as a promising technique for the treatment of patients with drug-refractory atrial fibrillation, however, the achievement of transmural lesions has remained a challenge. We evaluated the ability of a novel balloon-based cryogenic catheter system in achieving transmural lesions for PV isolation. METHODS: Six pulmonary vein ostia from three excised ovine hearts and lungs were used in this study. The balloon catheter was deployed and positioned at the ostia of the PVs and a full 8-minute ablation was then performed, while the heart was bathed in a circulating bath of normal saline at 37 degrees. Thermocouples positioned on the endocardial (balloon surface-tissue interface) and epicardial surfaces of the ostia were used to determine whether transmural freezing was achieved. RESULTS: The mean temperatures measured on the endocardial and epicardial tissue in six PV ablations were -38.8 +/- 6.9 degrees C and -10.0 +/- 7.5 degrees C, respectively. The average pulmonary vein thickness was 3.3 +/- 1.4 mm. CONCLUSIONS: A novel cryoablation balloon catheter is capable of achieving transmural freezing of the pulmonary vein. The catheter has promise for future clinical therapy of atrial fibrillation.