BARCELONA, Spain — Vagus nerve stimulation improved cardiac function and symptoms in patients with chronic HF, according to findings from the ANTHEM-HF study.
Inder S. Anand, MD, DPhil, said at a press conference that the researchers conducted the ANTHEM-HF study to determine whether electrical stimulation of the vagus nerve could restore autonomic balance, since autonomic imbalance is associated with progression of HF and worsening outcomes in patients with HF. The researchers also compared the effects of left and right vagus nerve stimulation. The results were simultaneously published in the Journal of Cardiac Failure.
Inder S. Anand
Anand, from the University of Minnesota Medical School, Minneapolis, and colleagues randomly assigned 60 patients with HF with reduced left ventricular ejection fraction (≤40%) and NYHA class II or III HF to a vagus nerve stimulation device (VNS Therapy System, Cyberonics) implanted on either the left side or right side of the vagus nerve.
After a 10-week titration period, patients received vagus nerve stimulation for 6 months at an amplitude of 2 mA and a constant frequency of 10 Hz.
The researchers observed 10 serious adverse events in the left-side group and 11 in the right-side group. Only one, a postsurgical embolic stroke for a patient in the left-side group, was related to the device or procedure; that patient died 3 days after the procedure. They observed no implant-related infections, system malfunctions or therapy inhibition via magnet.
“It is possible that manipulation of the common carotid artery in the neck during dissection of the vagus nerve caused plaque disruption or dislodged a thrombus,” Anand said in a press release. “Avoidance of this procedure in patients with severe obstructive carotid disease is likely to minimize such occurrences.”
In all patients, mean LVEF improved from 32.4% to 37.2% (mean change, 4.5%; P=.0001), with no difference between the left-side group and the right-side group.
Patients improved in 6-minute walk distance an average of 56 m from baseline to 6 months (P<.0001), but the left-side group had less improvement compared with the right-side group (34 m vs. 74 m; adjusted left-right difference, –43 m; 95% CI, –85 to –1.3), Anand said.
Patients also showed improvement in LV end-systolic diameter (P<.0025), NYHA class (P<.0001) and Minnesota Living with Heart Failure Questionnaire score (P<.0001), with no difference between the left-side and right-side groups, according to the researchers. There was no evidence of improvement in LV end systolic volume.
“Both left- and right-sided [autonomic regulation therapy] were associated with improvements in cardiac function and HF symptoms,” Anand said at the press conference. “Further investigation of [autonomic regulation therapy] in a controlled clinical study is warranted.”
For more information:
Anand IS. Hot Line III. Heart Failure: Devices and Interventions. Presented at: the European Society of Cardiology Congress; Aug. 30-Sept. 3, 2014; Barcelona, Spain.
Premchand RK. J Card Fail. 2014;doi:10.1016/jcardfail.2014.08.009.
Disclosure: The study was sponsored by Cyberonics. Anand reports financial ties with Amgen, Critical Diagnostics, Cyberonics, Novartis and Zensun.