Safety of catheter‐based radiofrequency renal denervation on branch renal arteries in a porcine model

OBJECTIVES: We aimed to investigate the safety of radiofrequency (RF)‐renal denervation (RDN) on branch renal arteries (RAs) in a porcine model. BACKGROUND: The efficacy of RF‐RDN was enhanced by treatment of the branch RA, in addition to the main RA. However, there are concerns regarding the safety of RF‐RDN on branch RA because of their smaller diameter and proximity to the kidney. METHODS: RF was delivered to 24 RA from 12 swine. A total of 8 RA from 4 swine were untreated. Treated RA were examined by angiography and histopathology at 7, 30, and 90 days. Serum creatinine concentration, biophysical parameters during RF delivery, and renal norepinephrine concentration were also assessed. RESULTS: Angiography revealed minimal late lumen loss and diameter stenosis in the main and branch RA at any time point. There was no change in serum creatinine after RF‐RDN. Histopathologically, no augmentation of medial damage or neointimal formation was found in branch RA compared with main RA. No or minimal damage to surrounding tissues including the kidneys, ureters, lymph nodes, and muscles was observed at any time point in both the main and branch RA. Equivalent electrode temperature in the main and branch RA was achieved by automatic adjustment of output power by the generator. The renal norepinephrine concentration was significantly lower in the treated group compared with the untreated group. CONCLUSIONS: RF‐RDN on branch RA was safe in a porcine model, with stenosis‐free healing of treated arteries and negligible kidney damage at 7, 30, and 90 days.