Endovascular and Cardiac Transcatheter Microwave Ablation

Background Radiofrequency catheter ablation has become a mainstay of treatment for cardiac arrhythmias, and in the emerging area of renal sympathetic denervation for hypertension. However, insufficient ablation depth, inconsistent contiguity of linear ablations, poor fat penetration, and vascular injury lead to suboptimal efficacy and safety. We demonstrate proof of concept for a plethora of novel microwave catheter designs for cardiac and endovascular ablation. Method Microwave catheter prototypes were designed, manually assembled, tested, and iteratively developed for pulmonary vein isolation, renal sympathetic denervation, and ventricular ablation. Thermal lesion characteristics and dosing were assessed for catheter prototypes in in-vitro models and optimised in large animal models to investigate clinical feasibility, efficacy and early safety. Results Transcatheter microwave ablation produced both circumferential and focal ablation patterns, as well as deep and controllable myocardial and perivascular lesions through fat and without significant vascular or collateral organ injury. We demonstrated that microwave catheter ablation can produce 1) circumferential pulmonary antral ablation without catheter contact for the treatment of atrial fibrillation, 2) deep circumferential perivascular ablation around the renal artery and effective renal denervation without significant arterial or collateral organ injury, 3) yield a procedural endpoint for renal denervation via abolition of aorticorenal ganglion pacing induced renal arterial vasoconstriction, and 4) produce deep myocardial ablations through fat with relative sparing to nearby coronary arteries and lung. Conclusion Transcatheter microwave ablation has the potential to overcome the limitations of conventional radiofrequency ablation. Clinical translation may improve treatment outcomes for atrial fibrillation, ventricular arrhythmias and hypertension