Novel Ways to Control BP
An investigational implantable device activates baroreceptors of the carotid sinus.
ORLANDO—At the American College of Cardiology annual meeting here, researchers reported promising results for two novel approaches to treating medically resistant hypertension. Should the early findings be validated, these approaches might be applicable to the 40 million Americans whose BP is not properly controlled.
The first approach involves baroreflex hypertension therapy using the Rheos Hypertension System (CVRx, Minneapolis). The device, which works by generating electrical pulses that exert incremental effects on BP lowering and heart rate, activates baroreceptors of the carotid sinus. Investigator Marcos Rothstein, MD, professor of medicine at Washington University School of Medicine in St. Louis, presented interim findings from a study of 38 patients in whom the device was implanted. On average, patients had a BP of 183/105 despite taking five antihypertensive medications.
At baseline, more than 80% of patients had a systolic BP (SBP) of 160 mm Hg or higher, but this proportion was reduced to 50% at year 1 and 42% at year 3. The proportion of patients with SBP less than 140 mm Hg rose from 5% at baseline to almost 30% after three years.
One year after implantation of the device, patients had a mean reduction in SBP and diastolic BP (DBP) of 25 and 15 mmHg, respectively, Dr. Rothstein reported. Patients also had a mean heart rate reduction of seven beats per minute. After three years of treatment, the mean reductions in SBP and DBP were 31 and 21 mm Hg, respectively, and the mean heart rate reduction was five beats per minute.
“Baroreflex hypertension therapy demonstrated clinically meaningful and sustained reductions in blood pressure in persons who had drug-resistant hypertension,” Dr. Rothstein said, suggesting that the results are “nothing short of revolutionary” in this patient group. Well over 200 patients have been treated with the Rheos therapy to date, Dr. Rothstein said.
John Bisognano, MD, PhD, associate professor of medicine and director of cardiac rehabilitation and clinical preventive cardiology at the University of Rochester, presented a poster on how the Rheos system improved heart structure and function over a 12-month period in 33 of the original 38 patients. All study participants also had echocardiograms performed before and 12 months after implantation.
Chronic use of the device-based approach improved cardiac structure and arterial compliance while reducing BP in 33 patients. There was a significant improvement in left ventricular mass index (-25 g/m2). Diurnal variation was preserved and the therapy proved safe, with a 20% rate of adverse events (mostly perioperative) and no unexpected serious adverse events. A randomized, double-blind, placebo-controlled phase 3 trial currently is accruing participants and is expected to enroll 300 patients from 50 centers.“Some [subjects] have mild-to-moderate renal insufficiency, and some have metabolic syndrome,” Dr. Rothstein noted. “Age is not a contraindication for the surgery. The success of the implants is more dependent upon specific neck anatomy and size, not age. Also it is important to note the Rheos therapy can be adjusted or personalized for each specific patient's requirements.”
“This is an innovative trial for a vexing problem, and these are fascinating and compelling data. The impact on structural heart disease indicates that the treatment is beneficial,” said Douglas Mann, MD, chief of the section of cardiology and professor of medicine at Baylor College of Medicine in Houston. He co-moderated the session at which Dr. Rothstein presented his findings.