The CardioFit System consists of an implantable neurostimulator, a sensing lead, and a stimulation lead. According to the manufacturer, device implantation can be performed using local or general anesthesia. A physician implants the neurostimulator under the skin near the clavicle, similar to cardiac pacemaker implantation. The neurostimulator’s battery is expected to last about four years. The sensing lead, which is placed through a vein into the heart’s right ventricular chamber, monitors heart activity and can halt stimulation if needed (e.g., unsafe reduction in heart rate). The stimulation lead, which is placed around the right vagus nerve just below the carotid artery bifurcation, delivers low-current electrical impulses from the neurostimulator.
About three weeks after system implantation, a physician programs and activates the system wirelessly, slowing increasing stimulation current over three to four weeks. Target stimulation strength depends on a patient’s heart rate (a marker of PNS activity) and HF symptoms. The system is designed to halt stimulation if heart rate drops by more than 10 beats per minute, thereby reducing the risk of dramatic and potentially unsafe, drops in heart rate. According to the manufacturer, the CardioFit System is compatible with implanted cardioverter defibrillators (ICDs), suggesting that ICDs may be used in conjunction with vagus nerve stimulation in some patients, depending on clinical need.
Note: The following ratings and comments reflect the opinions and consensus of an expert panel convened by ECRI Institute to review information on this topic.
Anticipated utilization: 2 (20 percent to 40 percent of patients)
The panel noted that physicians treating HF, while often quick to adopt new cardiac technology, are “very data driven” and would want to see data from large randomized trials to ensure safety and efficacy before adopting vagus nerve stimulation. If such data became available, and if the device is approved for HF in the United States, the panel thought the treatment might be used in up to 40 percent of eligible patients. Access to care, patient preference about undergoing a surgical procedure, and possible risk of adverse events were thought to be factors that might limit adoption.
The panel expressed concern about adverse events and a strong desire to see additional adverse event data from a larger confirmatory trial (see “Potential Health Impact” comment below).
Anticipated time to early adoption: 1 (Early adoption in 5 or more years)
Although vagus nerve stimulation is commercially available in Europe, results from a 650-patient, ongoing, phase III trial that would support a premarket approval application to the U.S. Food and Drug Administration are not expected until 2017. Add to that the time typically required for the premarket approval application submission and FDA approval processes, the CardioFit System, if approved, would not likely become clinically available before 2018.
Potential health impact: 2 (Small)
The panel noted that limited data (n = 32; phase II safety and tolerability trial by De Ferrari, et al. 2010) suggest vagus nerve stimulation to treat chronic HF may offer small-to-modest improvement in some measures of exercise tolerance and heart function.
The study reported that 32 serious adverse events (SAEs), including 3 deaths, occurred in 13 patients over the 12-month study period.
Two events (pulmonary edema and revision surgery) were categorized as “certainly related” to the device/procedure; six others were categorized as “possibly related” to the device/procedure; 23 SAEs (including the three deaths) were categorized as “probably not related” to the device/procedure; and one was categorized as “certainly not related.”
The panel thought that additional data from a large randomized controlled trial (RCT) (preferably blinded) would be needed to determine efficacy and enable clinicians and patients to adequately weigh potential benefits and harms. An ongoing phase III RCT is expected to be completed in 2017.
Potential financial impact: 4 (Substantial)
The device cost is expected to be similar to that of ICDs, according to the developer. The use of vagus nerve stimulation would significantly increase short-term treatment costs for advanced chronic HF compared to continued medical therapy alone.
Costs would increase more sharply if the technology were used in patients with an existing ICD. Additional evidence is needed to evaluate whether the use of vagus nerve stimulation could alter long-term treatment costs by reducing the incidence of hospitalizations to treat HF exacerbations or lowering the need for medical therapy.
Potential process and infrastructure impact: 3 (Moderate)
Major cardiac centers that treat large numbers of patients with chronic HF would be the most likely to adopt vagus nerve stimulation to treat HF. Such centers have in place teams with experience implanting other types of electronic cardiac implants; however, staff at these facilities would require additional training to implement the technology for the new indication, especially related to proper lead placement around the vagus nerve.
Use of vagus nerve stimulation would represent another electronic device for physicians to integrate into patient management and monitoring. If the technology is widely adopted, reallocation of significant staff and resources to the new program might be needed because the procedure would represent an additional patient population needing routine device-related follow-up.
De Ferrari GM, Crijns HJ, Borggrefe M, Milasinovic G, Smid J, et al. Chronic vagus nerve stimulation: a new and promising therapeutic approach for chronic heart failure. Eur Heart J 2011 Apr;32(7):847–55. Epub 2010 Oct 28. PMID: 21030409.
INOVATE-HF. [internet]. Yehud (Israel): BioControl Medical; [accessed 2012 Feb 24]. [1 p]. Available: http://www.biocontrol-medical.com/patients.php?ID=8.
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This is an update of an article published in October 2012.