Vagal-Nerve Stimulation Fails to Improve Cardiac Remodeling or Function: NECTAR-HF

August 30, 2014

BARCELONA, SPAIN — An investigational procedure designed to enhance parasympathetic tone by directly stimulating the vagal nerve failed to improve left ventricular end-systolic diameter (LVESD) in a group of heart-failure patients with low ejection fractions.

In addition, vagal-nerve stimulation failed to have an impact on other echocardiographic measurements of cardiac remodeling, such as left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic and -diastolic volumes (LVESV and LVEDV), and left ventricular ejection fraction (LVEF).

There was also no improvement in exercise capacity or N-terminal probrain natriuretic peptide (NT-proBNP) levels.

The results from the Neural Cardiac Therapy for Heart Failure (NECTAR-HF) study, which was led by Dr Faiez Zannad (Université de Lorraine, Nancy, France), were presented today during an afternoon press conference here at the European Society of Cardiology 2014 Congress .

Pilot Study Suggested Benefit

The rationale for NECTAR-HF stemmed from the hypothesis that vagal-nerve stimulation could normalize autonomic imbalances in HF patients and prevent the progression of disease. In a pilot study, which included 32 patients, there were improvements from baseline in LV remodeling and LV function, as well as improvements in NYHA class and six-minute-walk test. The pilot study, however, did not include a sham-treated control group like the NECTAR-HF randomized trial. For device trials, including this one, as well as the recent SYMPLICITY HTN-3 study testing renal denervation in patients with hypertension, it is important to include a sham-controlled therapy arm to protect against unintended placebo effects, investigators note.

Dr Faiez Zannad

In the phase 3 trial, 96 patients were randomized 2:1 to either vagal-nerve stimulation or a sham procedure. With the device, manufactured by Boston Scientific, a lead was implanted around the right vagus nerve in the cervical region while the lead body was placed under the clavicle. The pulse generator was implanted in a subcutaneous pectoral pocket.

At six months, there was no significant improvement in any measure of cardiac remodeling or functional capacity. Quality of life, as measured using the Minnesota Living with Heart Failure Questionnaire (MLHFQ), and NYHA functional class were both significantly improved with vagal-nerve stimulation.

The investigators say the quality-of-life and NYHA-functional-class results should be interpreted with caution given their subjective nature and the overall negative trial results. They point out that it was very difficult to adequately blind patients to the treatment, noting that more patients in the on-treatment group were able to guess that they were receiving vagal stimulation. One of the possible reasons for the ineffective blinding might be caused by the relatively high amplitude of vagal stimulation used in some patients, said Zannad.

The study was sponsored by Boston Scientific. Zannad receives honoraria from Air Liquide, Bayer, Biomérieux, Biotronik, Boston Scientific, CVCRx, Janssen, Novartis, Pfizer, Resmed, Roche Diagnostics, Sanofi, Servier, St Jude, and Takeda; speaker fees from Mitsubishi; and owns stock in CVCT and CardioRenal Diagnostics.

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