• Hypertensive Disease
• Cardiology

Hypertension (HTN) affects more than 25% of adults in developed societies [Wolf-Maier K et al. Hypertension 2004] and is a leading attributable cause of mortality worldwide, causing 7.5 million deaths annually [Symplicity HTN-1 Investigators. Hypertension 2011]. Every 20/10 mm Hg increase in blood pressure (BP) is associated with a doubling of cardiovascular mortality [Lewington S et al. Lancet 2002; Chobanian AV et al. Hypertension 2003]. Refractory or resistant hypertension, which is defined as elevated BP despite full doses of 3 antihypertensive agents, including a diuretic, is being increasingly recognized as a clinically important problem that might affect 13% of the hypertensive population [Geisler BP et al. J Am Coll Cardiol 2012].

Recently, catheter-based renal denervation treatment has proven to be a viable therapeutic approach for resistant HTN [Geisler BP et al. J Am Coll Cardiol 2012]. Horst Sievert, MD, PhD, Johann Wolfgang Goethe University Frankfurt, Frankfurt, Germany, discussed emerging technologies and new renal denervation devices in development.

A revolutionary treatment principle, renal denervation uses ablation of the renal sympathetic nerves with a radiofrequency (RF)-emitting catheter inserted percutaneously via the femoral artery into the lumen of both renal arteries [Laurent S et al. Lancet 2012]. The randomized controlled Symplicity HTN-2 trial confirmed a systolic BP (SBP) reduction of 32±23 mm Hg compared with a change of +1±21 mm Hg observed for standard of care (p<0.0001) from a baseline SBP of 178±17 mm Hg [Esler MD et al. Lancet 2010].

A multielectrode and RF-ablation–based system, EnligHTN, lowered patients' BP even faster. Thirty-day results in 47 resistant hypertension patients showed mean office BP changes at 1 month of −28 mm Hg systolic and −10 mm Hg diastolic (p<0.0001 from baseline), with 78% of patients having systolic BP drops of ≥10 mm Hg and 41% having SBP <140 mm Hg (Figure 1) [Worthley S et al. EuroPCR 2012]. In the ARSENAL study [NCT01438229] of the EnligHTN system, no serious complications were seen in the renal artery or at the access site; minor procedure-related events included 4 hematomas, 3 vasovagal responses to sheath removal, and 2 postprocedure transient bradycardias.

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Figure 1.

30-Day Results from St. Jude's Medical First-in-Man Study on the Multielectrode and RF-Ablation-Based EnligHTN System.

The renal denervation system OneShot received European CE mark clearance in February 2012 [Valigra L. Mass High Tech 2012]. Patients in its first-in-man [FIM] study (n=9) had baseline office SBP of 186±18 mm Hg and diastolic BP (DBP) of 91±14 mm Hg. The decrease in office SBP (155±19 mm Hg) and DBP (86±14 mm Hg) at 30 days was statistically significant (p<0.001; Figure 2) [Ormiston J et al. EuroPCR 2012]. The balloon was inflated to 1 atm for 2 minutes ablation of each side; irrigation cooling protected the nontreated region of the artery. Technical success was achieved in 8 of 9 patients. The only failure required minor reprogramming of the RF generator. The median total procedure time was 34 minutes; median fluoroscopy time was 8 minutes; median contrast volume 126 mL. No adverse events were reported.

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Figure 2.

30-Day Outcomes from Covidien's OneShot Renal Denervation System.

DBP=diastolic blood pressure; SBP=systolic blood pressure.

The Vessix V2 renal denervation system also has received European CE Mark approval. This system uses a balloon catheter with bipolar RF electrodes, low pressure (<3 atm), and simultaneous energy delivery to all electrodes. Suitable for renal arteries of 3 to 7 mm, treatment time is 30 seconds using <1/2 to 1 watt. In the Vessix FIM trial (n=7), 30-day results demonstrated declines in SBP of −28 mm Hg and in DBP of −11 mm Hg (95% CI) [REDUCE-HTN pilot clinical trial. EuroPCR 2012]. The response rate (defined as a change in SBP and DBP) was 100%. This compared to a 1 month −19 mm Hg drop in SBP and a −9 mm Hg decline in DBP seen in the Symplicity HTN-1 trial (n=138). A multicenter, international Vessix study is currently underway [REDUCE-HTN; NCT01541865]. It is the first clinical trial to treat patients with accessory renal arteries.

• © 2012 MD Conference Express®