The control subjects had a baseline blood pressure of 178/98 mm Hg despite being on an average of five antihypertensive drugs. After 6 months of usual care, their blood pressure had increased to 190/100 mm Hg. But 6 months after undergoing the ablation procedure, their average office blood pressure was 166/92 mm Hg.
One patient was hospitalized for post-procedure hypotension. This individual was treated with intravenous fluids and a reduction in antihypertensive medication and was discharged without further incident. Such occurrences have been quite rare among the roughly 4,000 patients treated worldwide to date, according to Dr. Esler, associated director of the Baker IDI Heart and Diabetes Institute, Melbourne.
Two patients in the control arm had a total of three hypertensive episodes requiring hospitalization during the 6-month usual care phase prior to crossover to renal denervation.
"These patients, of course, ended up as very good treatment responders," he said.
These severe hypertensive episodes while on usual care, along with the natural tendency of blood pressure to rise from baseline to crossover in the control group despite medication, underscore the potential costs in delaying renal denervation, Dr. Esler commented.
A pivotal Phase-3 Symplicity HTN-3 trial is underway in the United States, where renal denervation remains investigational. The study, led by Dr. George Bakris, president of the American Society of Hypertension and professor of medicine at the University of Chicago, involves more than 500 patients with resistant hypertension. It features a blinded crossover study design. The Symplicity system is commercially available in Australia, Europe, and Asia.
Dr. Sobotka is a paid advisor to Medtronic. Dr. Esler has received research grants from and is a paid consultant to Medtronic and Ardian.