Randomized Sham-Controlled Trial Examines Blood Pressure Effects of Renal Denervation in Patients with Mild Refractory Hypertension

Results of Symplicity Flex Trial Reported at TCT 2014

WASHINGTON, DC – According to a new small-to-modest sized but sham-controlled study, renal sympathetic denervation (RSD) used to treat mild refractory hypertension was associated with reductions in blood pressure in secondary analyses, but missed its primary endpoint. Findings from the Symplicity Flex trial were reported today at the 26th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. Sponsored by the Cardiovascular Research Foundation (CRF), TCT is the world’s premier educational meeting specializing in interventional cardiovascular medicine.

According to the Centers for Disease Control, 67 million American adults (31 percent) have high blood pressure and only about half (47 percent) have their condition under control. RSD is a minimally invasive catheter based procedure that uses radiofrequency ablation to treat resistant hypertension. There is little data with regard to the effectiveness of RSD in patients with refractory hypertension yet only mildly elevated blood pressure.

The Simplicity Flex trial randomized a total of 71 patients with refractory hypertension and mildly elevated blood pressure (daytime systolic BP of 135-149 and/or diastolic blood pressure of 90-94 mmHG on ambulatory BP measurement). One group received catheter-based RSD while the second group received an invasive sham procedure. All patients had a stable antihypertensive drug regimen of three or more agents including a diuretic, except when not tolerated or contraindicated. The primary endpoint was the change in 24 hour systolic blood pressure at six months.

The mean change in 24 hour systolic BP in the intention to treat (ITT) cohort at six months was -7.0 ± 10.6 mmHg for patients undergoing RSD and -3.5 ± 9.4 mmHg in the sham group (p=0.15). In the per protocol population, the change in 24 hour systolic blood pressure (BP) at six months was -8.3 ± 8.9 mmHG in the RSD group compared to -3.5 ± 9.5 mmHG in the sham group (p= 0.042). There was also a significant reduction in daytime systolic BP in RSD patients in the per protocol analysis (-9.9 ± 9.0 vs. -3.7 ± 9.9, p=0.012). No significant changes in the 24 hour diastolic, mean BP or any measures of nighttime BP were recorded and there were no serious adverse events.

“In patients with mild refractory hypertension, renal sympathetic denervation showed a significant reduction of 24 hour systolic BP in the per protocol cohort at six months, however in the intention to treat population the results were not significant,” said lead investigator Steffen Desch, MD University of Schleswig-Holstein, Campus Lübeck, in Germany.

“Findings indicate that this procedure could supplement current therapies and help reduce the number of patients with uncontrolled high blood pressure.”

The Symplicity Flex trial was funded by the Heart Center at the University of Leipzig. Dr. Desch reported no disclosures.

The Cardiovascular Research Foundation