After establishing access to the renal artery via the femoral artery, the catheter is advanced to the distal section of one renal artery. Low-power (<8?W) radiofrequency energy is delivered to the endothelial layer through an electrode for an average of 2?minutes. <a href="http://en.wikipedia.org/wiki/Oxygenase
">Oxygenase This leads to transmural lesions and damage to the sympathetic fibers traveling in the adventitia of the arterial wall. The catheter is then pulled back and radiofrequency energy applied 5 or 6 times longitudinally and circumferentially in the artery. This is repeated at the contralateral renal artery.32 One study used the PARADISE catheter (ReCor Medical, Ronkonkoma, NY).16 This catheter has a balloon that enables cooled fluid to circulate during the energy delivery process and keeps the artery wall cool, minimizing damage to nontarget tissues.16 The energy used with this catheter is higher than the Ardian catheter (25?W compared with approximately 8?W).16 The two studies by Prochnau and colleagues17,23 used the standard steerable radiofrequency ablation catheter. Efferent denervation decreases renin stimulation and potentiates natriuresis, while afferent denervation leads to decrease in the kidney��s contribution to central sympathetic activity.33 Our review suggests that renal sympathetic denervation would probably be suited for patients older than 18?years with resistant hypertension without NU7441 mouse
secondary causes. Patients who were pregnant, were taking anticoagulation with warfarin, or had heart failure were excluded from the studies. Intuitively, patients with chronic kidney disease and end-stage renal disease would benefit most from this technique as these patients have high a prevalence of resistant hypertension due to increased sympathetic activity.34 This theory has been supported by a small case series of 15 patients25 and is being investigated in ongoing clinical trials.34 Our review is limited by the quality of the included studies and the limited evidence base. Only two RCTs have been conducted to date. Although all studies claimed to exclude patients with secondary hypertension, it was not explicitly stated how this was accomplished. Ambulatory BP measurements were not consistently reported in all studies across the duration of follow-up. In the few studies that this was reported, the magnitude http://www.selleckchem.com/products/BKM-120.html
of reduction was smaller than the clinic BP recordings, which limits the translation of this technique to clinical benefit. Future research should focus on RCTs with longer follow-up to demonstrate the efficacy and safety of this technique in resistant hypertension. Symplicity HTN-3 is an ongoing RCT that will enroll 530 patients in various centers throughout the United States.35 Characteristics of ��nonresponders�� to the technique need to be studied to formulate effective exclusion criteria.