New data presented at the American Heart Association Scientific Sessions show that renal denervation significantly reduces blood pressure in patients with treatment-resistant hypertension. Murray Esler, Baker IDI Heart and Diabetes Institute, Melbourne, Australia, presented results from the Symplicity HTN-2 trial. The results were simultaneously published online in The Lancet.
Elser told delegates that “Activation of renal sympathetic nerves is key to pathogenesis of essential hypertension.” The proprietary radiofrequency generator used in the procedure is automatic, operates on low power and has built-in safety algorithms.
Investigators set out to assess effectiveness and safety of catheter-based renal denervation for reduction of blood pressure in patients with treatment-resistant hypertension.
Symplicity HTN-2 is a multicentre, prospective, randomised trial. Between 9 June 2009 and 15 January 2010, Esler et al randomised 106 patients who had a baseline systolic blood pressure of 160mmHg or more (≥150mmHg for patients with type 2 diabetes), despite taking three or more antihypertensive drugs in a one-to-one ratio to undergo renal denervation (n=52) with previous treatment or to maintain previous treatment alone (control group, n=54) at 24 participating centres. The primary effectiveness endpoint was change in supine office-based measurement of systolic blood pressure at six months. Primary analysis included all patients remaining in follow-up at six months.
Forty nine (94%) of 52 patients who underwent renal denervation and 51 (94%) of 54 controls were assessed for the primary endpoint at six months. Investigators found that office-based blood pressure measurements in the renal denervation group decreased by 32/12mmHg (+/- 23/1mmHg, baseline of 178/96mmHg; p
Between-group differences in blood pressure at six months were 33/11mmHg (p
At six months, 84% of the subjects receiving renal denervation had a decrease in systolic blood pressure of 10mmHg or more versus 35% of 51 controls (pThere were no major procedure-related or device-related complications.
Dierk Scheinert, Leipzig, Germany, who presented these results at the LINC annual meeting noted that there were no serious device- or procedure-related adverse events in the 52 patients. There was one femoral artery pseudoaneurysm treated with manual compression; one post-procedural drop in blood pressure resulting in a reduction in medication; one urinary tract infection; one prolonged hospitalisation for evaluation of paraesthesias and one back pain treated with pain medications which resolved after one month.
“Six month renal imaging in 43 patients showed no vascular abnormality at any radiofrequency treatment site. One magnetic resonance angiography indicates possible progression of a pre-existing stenosis unrelated to radiofrequency treatment with no further therapy warranted,” he said.
There were no changes in measured renal function with denervation, which suggests that the procedure itself and associated haemodynamic changes have no deleterious effects on the kidneys.