One end point assessed short-term response after 6 months, defining success as at least a 10-mm Hg drop in systolic pressure, compared with baseline. This criteria for success occurred in 54% of patients with an activated device in the study’s first 6 months and in 46% of those with an inactive device, an 8% difference in response rate between the active and control arms that failed to meet the prespecified goal of a 20% difference. Dr. Bisognano speculated that the placebo response may have been so high because of continued drug treatment optimization during this period.
The second end point assessed the 12-month response in all 265 patients, again using a 10-mm Hg drop in systolic pressure relative to baseline as the criterion for a positive response. This reduction occurred in 88% of patients, surpassing the prespecified success threshold of 65%.
The third end point focused on 30-day safety. The 25% of patients with an adverse event exceeded the prespecified threshold of 18%.
The fourth end point looked at safety at 6 months, with an adverse-event threshold in the active-treatment arm of no more than 15% greater than in the control arm. The results showed that patients receiving activation had a 2% reduced rate of adverse events, compared with the inactive, control arm, which meant the results fulfilled this criterion of success.
The fifth end point looked at the overall adverse event rate on active therapy in all 265 patients after 12 months. The 13% actual rate fell within the prespecified goal of less than 28%, meaning the results fulfilled this criterion of success.
The study also assessed efficacy another way, by tallying the percentage of patients whose systolic pressure dropped below 140 mm Hg. At the 6-month mark, this degree of blood pressure reduction occurred in 42% of patients receiving activation and in 24% of patients whose device had not yet been activated, a statistically significant difference. At the 12-month mark, 53% of the patients on continuous active treatment and 51% of those who switched from 6 months off treatment to 6 months on treatment reached this systolic pressure goal.
In addition, the study included an echocardiography substudy designed to assess the impact of baroreflex activation on left ventricular mass and shape. At baseline, these 60 patients had an average left ventricular mass index of 117 kg/m2. A year later, the average had dropped to 102 kg/m2, a statistically significant difference. Patients also shifted toward having more normalized left ventricular shapes, Dr. Bisognano reported in a separate talk at the meeting.
Dr. Bisognano said that he has received consulting fees or honoraria from CVrx, the company that is developing the carotid baroreflex activation device. Dr. Ram said that he has served on the speakers’ bureau for the Peer Group and for Advanced Health Media. Dr. Deedwania said that he had no disclosures.