Combined method of renal denervation in an animal model

Background: Currently, intra-arterial radiofrequency renal denervation is an only interventional treatment for resistant hypertension. However, available data are controversial since this method does not provide the long-term hypotensive effect. Objective: To compare the safety and efficacy of laparoscopic mechanical renal denervation and laparoscopic combined renal denervation using a radiofrequency clamp. Methods: Thirty sheep weighing 93.00 ± 3.72 kg were divided into two groups for mechanical laparoscopic renal denervation (group I, n = 15) and combined laparoscopic renal denervation with a radiofrequency clamp (group II, n = 15). The observation period lasted for six months. We assessed the following parameters: blood pressure (BP) in response to high-frequency electric stimulation from the lumen of the vessel, creatinine and uric acid levels, iatrogenic damage to the renal arteries based on angiography findings, and destruction of nerve fibers based on histological findings. Results: All the animals survived throughout the observation period. Creatinine and uric acid levels were within the normal ranges. Renal angiography did not reveal any iatrogenic stenosis. After six months, we found some BP response (elevated systolic BP ∆66.73 ± 6.63 mm Hg [p < 0.001], elevated diastolic BP ∆47.27 ± 5.98 mm Hg [p < 0.001]) to high-frequency electric stimulation in group I and no hypertensive response in group II. After six months, the animals were withdrawn for further histological assessment. Histology revealed complete destruction of the nerve fiber (demyelination) in group II and vacuolized swollen nerve fibers without any signs of demyelination in group I. Conclusion: Laparoscopic combined renal denervation is a safe and efficacious method with a stable hypotensive effect after six months in an animal model as compared to laparoscopic mechanical renal denervation.