Catheter-based renal denervation for drug-resistant hypertension by using a standard electrophysiology catheter

Aims: The endovascular application of low-dose radiofrequency (RF) energy to the renal arteries results in effective ablation of sympathetic nerve fibres leading to a significant lowering of blood pressure (BP). This study aims to examine the feasibility and safety of renal denervation by the use of a standard electrophysiology (EP) catheter. Methods and results: Twelve patients (mean age 62+/-14 years, nine male) with drug resistant hypertension despite medical treatment with at least four antihypertensive drugs underwent renal denervation by using a standard steerable RF ablation catheter with a 7 Fr diameter (Marinr(R); Medtronic Inc., Minneapolis, MN, USA). Low-power RF applications have been applied along the length of both renal arteries, consecutively. Assessment of 24 hour ambulatory BP was done at baseline, at one, and at three months following RF ablation. The mean reduction of 24 hour ambulatory BP was -11/-7 mmHg at one month and -24/-14 mmHg at three months (p<0.01 for systolic and p<0.03 for diastolic blood pressure) with unchanged medication. No vascular complications have been observed in the short-term follow-up. The renal function as assessed by serum creatinine and proteinuria remained unchanged from baseline. Conclusions: Our preliminary results indicate that the use of a standard RF ablation catheter is feasible and safe for sympathetic renal denervation as shown by a significant lowering of mean 24 hour ambulatory BP in comparison to baseline during short-term follow-up. Whether the use of a standard EP catheter for sympathetic renal denervation indeed improves the long-term outcome in resistant hypertension, however, remains to be investigated.