The Symplicity renal denervation system (Medtronic) provides safe, significant and sustained blood pressure reduction up to three years in patients with treatment-resistant hypertension, according to data from two clinical trials presented at the 2012 American College of Cardiology (ACC) meeting.
Results from the SYMPLICITY HTN-1 trial showed sustained safety and effectiveness of renal denervation with the Symplicity system up to three years, and results from the SYMPLICITY HTN-2 trial showed safe, sustained and significant blood pressure reduction one year following the procedure. These data were presented today during an oral session at ACC.12 dedicated to renal denervation as a novel therapy for treatment of treatment-resistant hypertension.
Renal denervation therapy is a minimally invasive, catheter-based procedure that modulates the output of nerves that lie within the renal artery wall and lead into and out of the kidneys. These nerves are part of the sympathetic nervous system, which affects the major organs that are responsible for regulating blood pressure: the brain, the heart, the kidneys and the blood vessels.
SYMPLICITY HTN-1 trial
SYMPLICITY HTN-1 is a series of pilot studies involving 153 patients at 19 centres in Australia, Europe and the United States. Subjects in the SYMPLICITY HTN-1 trial maintained an average blood pressure reduction of -33/-19mmHg at 36 months (n=24) from baseline (p<0.001) following treatment with the Symplicity system. An increasing proportion of patients who completed follow-up had at least a 10mmHg reduction in systolic blood pressure. At six months 71% of patients were classified as responders, which increased to 100% among the patients who completed three year follow-up. There was no evidence of renal impairment, no patients were hospitalised due to hypotension, and no procedure-related serious adverse events were seen.
“As the duration of follow-up in these SYMPLICITY clinical trials grows, so too does our confidence in the enduring safety and effectiveness of the Symplicity system,” said George Bakris, professor of medicine and director of the ASH Comprehensive Hypertension Center at the University of Chicago Medicine and president of the American Society of Hypertension. “These are the longest term data to date involving renal denervation and results from these studies add to the growing body of evidence about this technology.”
SYMPLICTY HTN-2 trial
The SYMPLICITY HTN-2 trial is an international, multicentre, prospective, randomised, controlled study of the safety and effectiveness of renal denervation in patients with treatment-resistant hypertension. One hundred-six (106) patients were randomly allocated in a one-to-one ratio to undergo renal denervation with previous treatment or to maintain previous treatment alone (control group) at 24 participating centres. At baseline the randomised treatment and control patients had similar high blood pressures: 178/97mmHg and 178/98mmHg, respectively, despite both receiving an average daily regimen of five antihypertensive medications.
The analysis included data from 47 patients initially treated, who at 12 month follow-up sustained their significant drop in blood pressure (-28/-10mmHg [p<0.001] from baseline) with no significant difference from the previously reported six-month follow-up (-32/-12mmHg [p=0.16]). In addition, 35 qualified patients in the control group who received renal denervation six months post randomisation also showed a similar drop in blood pressure to the treatment arm at six months post procedure (-24/-8mmHg [p= 0.15] from six month treatment arm). Safety results were sustained with no significant decline in kidney function and no late vascular complications.
“These results demonstrate that the Symplicity system has the potential to provide long-term safety and efficacy for patients who have been unable to achieve target blood pressure levels despite multiple medications,” said Murray Esler, principal investigator of the SYMPLICITY HTN-2 trial and associate director of the Baker IDI Heart and Diabetes Institute of Melbourne, Australia. “We are extremely pleased with these results to date and our follow-up continues.”