The striking gains in functional capacity and quality of life conferred by baroreflex activation therapy in patients with heart failure, as shown in the pivotal phase 3 clinical trial for this novel intervention, were at least as great in women as in men, JoAnn Lindenfeld, MD, said at the European Society of Cardiology Heart Failure Discoveries virtual meeting.
The results of the multicenter, prospective, randomized BeAT-HF trial led to marketing approval of the BaroStim Neo system for improvement in symptoms of heart failure with reduced ejection fraction (HFrEF) by the Food and Drug Administration in August 2019. Dr. Lindenfeld presented a fresh breakdown of the results by gender which showed, intriguingly, that the improvement in all study endpoints was consistently numerically greater in the women – sometimes startlingly so – although these gender differences in response didn’t achieve statistical significance. The 6-month randomized trial was underpowered for drawing definitive conclusions on that score, with a study population of only 53 women and 211 men. So the investigator remained circumspect.
“We think that what this study shows us is that women have at least equivalent improvement as men in this population. I don’t think we can conclude from this study yet that it’s better, but it’s certainly in all these parameters as least as good. And I think this is a population in which we’ve seen that improving symptoms and functional capacity is very important,” said Dr. Lindenfeld, professor of medicine and director of advanced heart failure/cardiac transplantation at Vanderbilt University, Nashville, Tenn.
The FDA approval was restricted to patients like those enrolled in BeAT-HF: that is, individuals with New York Heart Association functional class III heart failure, a left ventricular ejection fraction of 35% or less while on stable optimal medical therapy, and ineligibility for cardiac resynchronization therapy according to current guidelines. Seventy-eight percent of BeAT-HF participants had an implantable cardioverter-defibrillator.
Participants were randomized to baroreflex activation therapy (BAT) plus optimal medical therapy or to optimal medical therapy alone. The three coprimary endpoints were change from baseline to 6 months in 6-minute hall walk distance (6MHW), scores on the Minnesota Living with Heart Failure Questionnaire (MLHF), and N-terminal pro-B-type natriuretic peptide (NT-proBNP).
In the overall study population, 6MHW increased by 60 m in the BAT group and decreased by 8 m in controls; MLHF scores dropped by 14 and 6 points, respectively; and NT-proBNP fell by an average of 25% with BAT while rising by 3% in controls.
Very often, just a 5-point reduction in MLHF score is considered a clinically meaningful improvement in quality of life, the cardiologist noted.
The gender-based analysis is where things got particularly interesting.
The investigators defined a clinically relevant response as a greater than 10% increase from baseline on the 6MHW, at least a one-class improvement in NYHA class, or a reduction of 5 points or more on the MLHF. Among subjects in the BAT group, 70% of women and 60% of men met the clinically relevant response standard in terms of 6MHW, as did 70% of women and 64% of men for improvement in NYHA class, and 78% of women and 66% of men for MLHF score.
Eighty-seven percent of women and 68% of men on BAT had a clinically relevant response on at least one of these endpoints, as did about 28% of controls. Moreover, 31% of women in the BAT group were clinically relevant responders on at least two endpoints, compared with 19% of BAT men and 4% and 9% of controls.