Safety and efficacy of Catheterbased renal sympathetic denervation in resistant hypertension

Abstract

SUMMARY D espite the availability of multiple classes of orally active antihypertensive treatments, resistant hypertension remains an important public health issue. The failure of purely pharmacological approaches to treat resistant hypertension has stimulated interest in invasive device-based treatments. A new catheter system using radiofrequency energy has been developed allowing an endovascular approach to renal denervation and providing patients with resistant hypertension with a new therapeutic option. To date, this technique has been evaluated only in open-label trials including small numbers of highly selected patients with suitable renal artery anatomy. The involvement of the autonomic nervous system, including the renal sympathetic system, in particular, in the pathophysiology of arterial hypertension was recently highlighted by the publication of preliminary results for the use of catheter-based radiofrequency renal-nerve ablation to treat resistant hypertension. So, the aim of this study was to assess the safety & blood pressure lowering efficacy of percutaneous renal sympathetic denervation in patients with resistant hypertension. The current study included 30 patients with resistant hypertensionfrom April 2012 to April 2013. We performed renal sympathetic denervation for the 30 patients. Follow up was done during the 1st 6 months after renal sympathetic denervation. The suitable candidates were subjected to the following: • Detailed medical history. • Full clinical examination. • Laboratory investigations including: 1. Blood urea, serum creatinine and eGFR. 2. Serum Na and K. • ECG: resting 12 lead ECG before the renal denervation. • Renal artery duplex investigation before and after the renal denervation. • Renal denervation via The Symplicity Catheter System. The study device: It consists of a single-use, 6 French compatible electrode-tipped catheter designed specifically for endovascular delivery into the renal arteries.It is connected to a low-power radiofrequency (RF) generator that automatically controls energy delivery using a proprietary algorithm based on temperature and impedance feedback. The procedure: The renal artery was catheterized via standard femoral access, and renal angiography was then performed, when an ACT of 250–300 seconds had been achieved, a Symplicity electrode was introduced. The radiopaque tip of the electrode was brought into contact with the endothelium, initially at the most distal point of the renal trunk. A bilateral treatment of the renal arteries was performed with the use of series of 2-minute RF energy deliveries along each artery, aiming at 4–6 treatment points per artery. These treatment points are made with a minimum of 5 mm distance in between and with a pullback from distal to proximal in a circumferential way. A control angiography was performed after the procedure. All the data were analyzed and correlated to each other. A highly significant decrease in the systolic blood pressure of the case study was noted at 1, 3 and 6 months after denervation (p=0.001). There was 13decrease in the systolic blood pressure after 3 months and 19 mmHg decrease after 6 months. Regarding the diastolic blood pressure, there was also a highly significant decrease after denervation (p=0.001). A decline in DBP of the patients by 4 mmHg after 3 months and 11 mmHg after 6 months was recorded. We concluded that renal sympathetic denervation can be performed safely and effectively in patients with resistant hypertension to produce a substantial reduction of blood pressure.