Medtronic announced new results from SYMPLICITY HTN-2, the only randomised clinical trial investigating safety and efficacy of renal denervation. The 18-month data presented for the first time at the European Society of Cardiology (ESC) Congress on 26 August 2012 showed that the Symplicity system continues to provide superior and sustained blood pressure reduction in patients with treatment-resistant hypertension. The safety of renal denervation with the Symplicity system was also maintained at 18 months, with no device-related serious adverse events and no newly reported vascular complications from 12–18 months.
“We continue to see significant and sustained improvement in blood pressure levels for patients who receive renal denervation with the Symplicity system, as these 18-month average blood pressure reductions are consistent with the 12-month follow-up data for both groups,” 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. “This is encouraging since patients with treatment-resistant hypertension are often taking more than three antihypertensive medications and still are unable to control their blood pressure, which can put them at risk for various cardiovascular events such as heart attack, stroke or heart failure.”
In this trial, 43 patients initially randomised to renal denervation with the Symplicity system had an average blood pressure reduction of -32/-12mmHg from baseline (p<0.01) at 18 months. Thirty one control patients who received renal denervation following the six-month primary endpoint (crossover group) had an average blood pressure reduction of -28/-11mmHg (p<0.01) at 18 months. These 18-month average blood pressure reductions are maintained for both groups from 12–month follow-up (-28/-10mmHg [p<0.01] for the initial treatment group; -24/-10mmHg [p<0.01] for the crossover group).
The average number of medications for patients in this trial did not change from baseline to 18 months. At 18months, pulse pressure improved significantly for patients in this analysis following treatment with the Symplicity system (-20mmHg from baseline for the initial treatment group [p<0.01]; and -18mmHg from baseline for the crossover group [p<0.01]). Pulse pressure is the numeric difference between systolic and diastolic blood pressure and may have predictive value in terms of cardiovascular complications, especially in older patients. It may be important to evaluate changes in pulse pressure as well as systolic and diastolic blood pressure when assessing the efficacy of antihypertensive therapy. This analysis showed three new hospitalizations in the initial renal denervation group due to hypertensive events.
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.
The Symplicity system’s catheter and proprietary generator and algorithms were carefully and specifically developed through years of clinical experience to enhance the safety and effectiveness of the renal denervation procedure. The Symplicity renal denervation system has been successfully used for five years to treat nearly 5,000 patients with treatment-resistant hypertension worldwide. The Symplicity renal denervation system is not approved by the US Food and Drug Administration (FDA) for commercial distribution in the United States.