Medtronic announced on 22 October new results from Symplicity HTN-1, the longest running clinical trial investigating the safety and efficacy of renal denervation. These data showed patients who received renal denervation treatment with the Symplicity system experienced a mean blood pressure reduction of -29/-14mm Hg (p<0.01) at 24 months (n=105).
These data expand the total number of patients to nearly two times the number previously reported at 24 months (n=59) from this clinical trial. The safety of renal denervation with the Symplicity system was also maintained at 24 months. The expanded two year cohort data were presented for the first time today at the 24th Annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. The Symplicity system is only available for investigational use in the United States.
“These clinical trial results provide important evidence and confidence for physicians that renal denervation with the Symplicity system continues to be safe and effective in reducing blood pressure over time in patients with treatment-resistant hypertension, who are at high risk for various cardiovascular events,” said Markus Schlaich, professor of medicine and head of Hypertension and Kidney Disease at the Baker IDI Heart and Diabetes Institute in Melbourne, Australia. “These data in nearly twice the number of patients previously reported at two years in this trial provide us with a better understanding of the patient response over time and add to the growing body of evidence supporting the safety and sustained blood pressure reduction of renal denervation treatment with the Symplicity system.”
Responder rates (defined as a 10mmHg reduction) among patients completing follow–up increased from 69% at one month to 82% at 24 months. Safety follow-up at 24 months demonstrated continued stable renal function with no new episodes of hypotension, orthostasis, or renal artery stenosis related to the renal denervation procedure; adverse events due to co-morbid diseases such as infection and non-renal surgical complications were reported.
Pulse pressure improved significantly following treatment with the Symplicity system, with a reduction of -15mmHg (p<0.01) from baseline for the expanded patient cohort (n=105) at 24 months. Pulse pressure is the numeric difference between systolic and diastolic blood pressure and may have independent predictive value beyond absolute blood pressure measurements alone 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.
In this same analysis there were 34 patients available for follow-up at 36 months vs. 24 patients available at three years in the previously reported data. These 34 patients experienced a mean blood pressure reduction of -31/-16mmHg (p<0.01) at 36 months. For the patients in this analysis who were available for follow-up at 36 months there was a -16mmHg (p<0.01) reduction in pulse pressure following treatment with the Symplicity system. Responder rates among patients completing follow-up increased to 94% at 36 months.
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.