Coverage Policy Manual
Policy #: 2009044
Category: Surgery
Initiated: November 2009
Last Review: March 2024
  Vagus Nerve Stimulation

Description:
Vagus nerve stimulation (VNS) was initially investigated as a treatment alternative in patients with medically refractory partial-onset seizures for whom surgery is not recommended or for whom surgery has failed. Over time, the use of VNS has expanded to include generalized seizures, and it has been investigated for a range of other conditions.
 
While the mechanisms for the therapeutic effects of VNS are not fully understood, the basic premise of VNS in the treatment of various conditions is that vagal visceral afferents have a diffuse central nervous system projection, and activation of these pathways has a widespread effect on neuronal excitability. An electrical stimulus is applied to axons of the vagus nerve, which have their cell bodies in the nodose and junctional ganglia and synapse on the nucleus of the solitary tract in the brainstem. From the solitary tract nucleus, vagal afferent pathways project to multiple areas of the brain. VNS may also stimulate vagal efferent pathways that innervate the heart, vocal cords, and other laryngeal and pharyngeal muscles, and provide parasympathetic innervation to the gastrointestinal tract.
 
A type of VNS device addressed in this evidence review consists of an implantable, programmable electronic pulse generator that delivers stimulation to the left vagus nerve at the carotid sheath. The pulse generator is connected to the vagus nerve via a bipolar electrical lead. Surgery for implantation of a vagal nerve stimulator involves implantation of the pulse generator in the infraclavicular region and wrapping 2 spiral electrodes around the left vagus nerve within the carotid sheath. The programmable stimulator may be programmed in advance to stimulate at regular intervals or on demand by patients or family by placing a magnet against the subclavicular implant site.
 
Various types of devices that transcutaneously stimulate the vagus nerve have been developed as well. The U.S. Food and Drug Administration (FDA) has not approved any transcutaneous VNS devices.
 
Other types of implantable vagus nerve stimulators that are placed in contact with the trunks of the vagus nerve at the gastroesophageal junction are not addressed in this policy.
 
Indications
VNS was originally approved for the treatment of medically refractory epilepsy. Significant advances have been made since then in the surgical and medical treatment of epilepsy, and newer, more recently approved medications are available. Despite these advances, however, 25% to 50% of patients with epilepsy experience breakthrough seizures or suffer from debilitating adverse events of antiepileptic drugs. For these patients, VNS therapy has been used as an alternative or adjunct to epilepsy surgery or medications.
 
Based on observations that patients treated with VNS experience improvements in mood, VNS has been evaluated for the treatment of refractory depression. VNS has been investigated for multiple other conditions which may be affected by either the afferent or efferent stimulation of the vagus nerve, including heart failure, headaches, tremor, fibromyalgia, tinnitus, and traumatic brain injury.
 
REGULATORY STATUS
In 1997, the NeuroCybernetic Prosthesis (NCP®) System (Cyberonics), a VNS device, was approved by FDA through the premarket approval process for use in conjunction with drugs or surgery “…as an adjunctive treatment of adults and adolescents over 12 years of age with medically refractory partial onset seizures” (FDA, 2017). There have been subsequent expanded approvals. FDA product code: LYF.
 
In 2005, the FDA expanded the indication to include the treatment of adjunctive long-term treatment of chronic or recurrent depression for patients 18 years of age or older experiencing a major depressive episode and have not had an adequate response to 4 or more adequate antidepressant treatments.
 
In 2017 the PMA was further expanded to include use as adjunctive therapy for seizures in patients four years of age or older with partial-onset seizures that are refractory to antiepileptic medications.
 
In May 2015, a related VNS therapy, AspireSR® (LivaNova), received supplemental premarketing approval from FDA, although the device was recalled in August 2017 (FDA, 2017). The AspireSR® device detects high heart rates associated with seizures and responds with stimulation. Adjunctive use of the AspireSR® for the treatment of epileptic seizures was indicated for patients over 4 years of age who suffer from partial-onset seizures that do not respond to antiepileptic medication.
 
In May 2017, the gammaCore-S® (electroCore), a noninvasive VNS device, was cleared for marketing by FDA through the 510(k) process (K171306) for the acute treatment of adults with episodic cluster headaches (FDA, 2017). When the device is applied to the side of the neck by the patient, mild electrical stimulation of the vagus nerve is carried to the central nervous system. Each stimulation using gammaCore-S® lasts 2 minutes. The patient controls the stimulation strength. FDA product codes: PKR, QAK.
 
The gammaCore-2®, gammaCore-Sapphire® (manufactured by Electrocore) received approval/clearance 2017/2018/2021 [PMS/510(k) K172270/K180538/K182369/K191830/K203456/K211856] for adjunctive use for the preventive treatment of cluster headache in adult patients. The acute treatment of pain associated with episodic cluster headache in adult patients. The acute treatment of pain associated with migraine headache in adult patients. The preventive treatment of migraine headache in adult patients. FDA product code PKR
 
Cerbomed (Erlangen, Germany) has developed a transcutaneous VNS (t-VNS®) system that uses a combined stimulation unit and ear electrode to stimulate the auricular branch of the vagus nerve, which supplies the skin over the concha of the ear. Patients self-administer electrical stimulation for several hours a day; no surgical procedure is required. The device received the CE mark in Europe in 2011 but has not been FDA-approved for use in the United States.
 
CODING
Vagus nerve stimulation requires not only the surgical implantation of the device but also subsequent neurostimulator programming, which occurs intraoperatively and typically during additional outpatient visits. There are CPT codes that specifically describe the neurostimulator programming and analysis of cranial nerve stimulation (ie, vagus nerve) as follows:
 
95974 Electronic analysis of implanted neurostimulator pulse generator system (e.g., rate, pulse amplitude, pulse duration, configuration of wave form, battery status, electrode selectability, output modulation, cycling, impedance, and patient compliance measurements); complex cranial nerve neurostimulator pulse generator/transmitter, with intraoperative or subsequent programming, with or without nerve interface testing, first hour (CPT code deleted 12/31/2018)
 
95975 complex cranial nerve neurostimulator pulse generator/transmitter, with intraoperative or subsequent programming, with or without nerve interface testing, each additional 30 minutes after the first hour. (CPT code deleted 12/31/2018)
 
95976 Electronic analysis of implanted neurostimulator pulse generator/transmitter (e.g., contact group[s], interleaving, amplitude, pulse width, frequency [Hz], on/off cycling, burst, magnet mode, dose lockout, patient selectable parameters, responsive neurostimulation, detection algorithms, closed loop parameters, and passive parameters) by physician or other qualified health care professional; with simple cranial nerve neurostimulator pulse generator/transmitter programming by physician or other qualified health care professional (Eff. Jan 1, 2019)
 
95977  Electronic analysis of implanted neurostimulator pulse generator/transmitter (e.g., contact group[s], interleaving, amplitude, pulse width, frequency [Hz], on/off cycling, burst, magnet mode, dose lockout, patient selectable parameters, responsive neurostimulation, detection algorithms, closed loop parameters, and passive parameters) by physician or other qualified health care professional; with complex cranial nerve neurostimulator pulse generator/transmitter programming by physician or other qualified health care professional (Eff. Jan 1, 2019)
 
Vagus nerve stimulation has been evaluated for the treatment of obesity. This indication is addressed in policy 2015015 Vagal Nerve Blocking Therapy for the Treatment of Obesity.

Policy/
Coverage:
Effective August 2018
 
Meets Primary Coverage Criteria Or Is Covered For Contracts Without Primary Coverage Criteria
 
Vagus nerve stimulation as a treatment of medically refractory seizures meets member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.
 
Does Not Meet Primary Coverage Criteria Or Is Investigational For Contracts Without Primary Coverage Criteria
 
Vagus nerve stimulation as a treatment of other conditions, including but not limited to depression, heart failure, upper-limb impairment due to stroke, essential tremor, headaches, fibromyalgia, tinnitus, and traumatic brain injury does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.
 
For members with contracts without primary coverage criteria, vagus nerve stimulation as a treatment of other conditions, including but not limited to depression, heart failure, upper-limb impairment due to stroke, essential tremor, headaches, fibromyalgia, tinnitus, and traumatic brain injury is considered investigational. Investigational services are specific contract exclusions in most member benefit certificates of coverage.
 
Transcutaneous (nonimplantable) vagus nerve stimulation devices do not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.
 
For members with contracts without primary coverage criteria, transcutaneous (nonimplantable) vagus nerve stimulation devices are considered investigational. Investigational services are specific contract exclusions in most member benefit certificates of coverage.

Rationale:
Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function-including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.
 
To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. RCTs are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice. The following is a summary of the key literature to date.
 
VAGUS NERVE STIMULATION
 
Clinical Context and Test Purpose
The purpose of implantable vagus nerve stimulation (VNS) is to apply pulsed electrical energy via the vagus nerve to alter aberrant neural activity resulting in seizures.
 
The question addressed in this evidence review is this: Does the use of VNS as a treatment for medically refractory seizures result in changes in management and improvement in health outcomes?
The following PICOTS were used to select literature to inform this review.
 
Patients
The relevant population of interest is patients with medically refractory seizures.
Interventions
The test being considered is implantable VNS.
Comparators
The following practices are currently being used: conventional antiepileptic drugs and/or resective surgery.
Outcomes
Outcomes of interest are clinical validity or diagnostic accuracy (test accuracy, test validity [eg, sensitivity, specificity]), and clinical utility that includes consideration of avoidance of harms.
Timing
VNS is typically used when a patient has had unsuccessful medical therapy, been intolerant of medical therapy, or had failed resective surgery.
Setting
VNS is initiated with surgical implantation and subsequently administered in outpatient and home care settings.
Systematic Reviews
Reports on the use of VNS to treat medication-resistant seizure disorders date to the 1990s and were coincident with preapproval and early post-approval study of the device.
 
Treatment-Resistant Seizures
VNS for Adult Partial-Onset Seizures
Englot et al conducted a meta-analysis of the literature through November 2010 assessing the efficacy of VNS and its predictors of response (Englot, 2011). Overall, VNS predicted a 50% or greater reduction in seizure frequency at last follow-up, the main effect, with an odds ratio of 1.83 (95% confidence interval [CI], 1.80 to 1.86; p<0.001).
 
This evidence review was informed, in part, by a 1998 TEC Assessment on the treatment of seizures that offered the following conclusions (BCBSA TEC, 1998):
 
    • For patients, 12 years of age and older with medically refractory partial-onset seizures, for whom surgery is not recommended or for whom surgery has failed evidence, is available from 2 multicenter, randomized, blinded, active control studies submitted for device registration (Ben-Menachem, 1994; Handforth, 1998). The trials, which were limited to patients with partial-onset seizures, and included outcomes for 314 patients, presented sufficient data to demonstrate that VNS is a beneficial adjunct to optimal antiepileptic drug therapy for the treatment of these seizures. In patients with at least 6 partial-onset seizures per month, VNS reduced seizure frequency by approximately 25% after 3 months of treatment. In patients who achieved an initial reduction in seizure frequency, the beneficial treatment effect appeared to be maintained and may increase with time.
 
    • Adverse events were mild and consisted primarily of hoarseness or voice change during “on” periods of stimulation.
 
Based on this TEC Assessment, earlier versions of this evidence review supported the use of VNS for partial-onset seizures for patients older than 12 years of age in individuals for whom surgery has not been recommended or for whom surgery has failed.
 
Panebianco et al updated a Cochrane systematic review and meta-analysis of VNS to treat partial seizures (Panebianco, 2015). Reviewers specifically evaluated randomized, double-blind, parallel or crossover, controlled trials of VNS as add-on treatment comparing high- and low-stimulation paradigms plus VNS stimulation with no stimulation or a different intervention. Five trials (n=439 participants) compared high-frequency stimulation with low-frequency stimulation in participants ages 12 to 60 years, and another trial compared high-frequency stimulation with low-frequency stimulation in children (Handforth, 1998; DeGiorgio, 2005; Klinkenberg, 2012; Michael, 1993; The Vagus Nerve Stimulation Study Group, 1995). The overall relative risk for a response to high stimulation compared with low-stimulation using the fixed-effect model was calculated to be 1.73 (95% Cl, 1.13 to 2.64; p=0.01), showing that patients receiving high stimulation were more likely to show a 50% or greater reduction in seizure frequency.
 
Randomized Controlled Trials
Ryvlin et al reported on an RCT on long-term quality of life outcomes for 112 patients with medication-resistant focal seizures, which supported the beneficial effects of VNS for this group (Ryvlin, 2014).
 
VNS for Adult Generalized Seizures
Resective surgery is a less attractive therapeutic option for individuals with generalized treatment-resistant seizures that may be multifocal or involve an eloquent area. VNS has been evaluated as an alternative to disconnection procedures such as surgical division of the corpus callosum.
 
The evidence for the efficacy of VNS for generalized seizures in adults is primarily from observational data, including registries and small cohort studies.
 
Englot et al examined freedom from seizure rates and predictors across 5554 patients enrolled in the VNS Therapy Patient Outcomes Registry (Englot, 2016). The registry was established in 1999, after the 1997 U.S. Food and Drug Administration approval of VNS, and is maintained by the manufacturer of the device, Cyberonics. Data were prospectively collected by 1285 prescribing physicians from 978 centers (911 in the United States and Canada and 67 internationally) at patients’ preoperative baselines and various intervals during therapy. During active data collection, participation in the registry included approximately 18% of all implanted VNS devices. The database was queried in January 2015, and all seizure outcomes reported with the 0- to 4-, 4- to 12-, 12- to 24-, and 24- to 48-month time ranges after VNS device implantation were extracted and compared with patient preoperative baseline. Available information was tracked at each time point of data submission for the following outcomes: patient demographics, epilepsy etiology and syndrome, historical seizure types and frequencies, quality of life, physician global assessment, current antiepileptic drugs, medication changes, malfunctions, battery changes, and changes in therapy. At each observation point, responders were defined as having a 50% or greater decrease in seizure frequency compared with baseline and nonresponders as less than a 50% decrease. A localized epilepsy syndrome such as partial-onset seizures was recorded in 59% of the registry participants, generalized epilepsy in 27%, and 11% had a syndromic etiology (eg, Lennox-Gastaut).
 
Garcia-Navarrete et al evaluated outcomes after 18 months of follow-up for a prospective cohort of 43 patients with medication-resistant epilepsy who underwent VNS implantation (Garcie-Navarrete, 2013). Subjects’ seizure types were heterogeneous, but 52% had generalized epilepsy. Pharmacotherapy was unchanged during the study. Twenty-seven (63%) subjects were described as “responders,” defined as having a 50% or greater reduction in seizure frequency compared with the year before VNS implantation. The difference in reduction of seizure frequency was not statistically significant between subjects with generalized and focal epilepsy.
 
VNS for Pediatric Seizures
The evidence for VNS for pediatric seizures consists of a variety of small noncomparator trials, prospective observational studies, and retrospective case series. As in the adult studies, there is heterogeneity of seizure etiologies: mixed, syndromic, and idiopathic; there is also generalized and limited information on concomitant antiepileptic drug requirement. Some studies have defined pediatric patients as less than 12 years of age and others have defined them as less than 18 years and may have included patients as young as 2 to 3 years of age. Study subpopulations may have had prior failed resective surgery. Complete freedom from seizures is the exception, and the primary reported end point is 50% or more reduction in seizure frequency, determined over varying lengths of follow-up. There is an overlap of authors for multiple studies suggesting utilization of VNS in specialized clinical care environments. Multiple studies have some form of innovator device company sponsorship.
 
Summary: Treatment-Resistant Seizures
The evidence on the efficacy of VNS for treatment of medically refractory seizures consists of 2 RCTs reported at the time of initial U.S. Food and Drug Administration approval of the marketed device, two recent meta-analysis, and numerous uncontrolled studies. The RCTs both reported a significant reduction in seizure frequency with VNS for patients with partial-onset seizures. The uncontrolled studies and case series have consistently reported reductions of clinical significance, defined as a 50% or more reduction in seizure frequency in both adults and children over almost 2 decades of publications. Interpretation of all outcomes and results were limited by the variety of comparators (when used), variability in length of follow-up, limited published data on antiepileptic medication requirements, mixed seizure etiologies, and history of prior failed resective surgery. There is an overlap of authors across multiple studies, suggesting utilization of VNS in specialized clinical care environments. Multiple studies have some form of innovator device company sponsorship.
 
Treatment-Resistant Depression
Interest in the application of VNS for treatment of treatment-resistant depression is related to reports of improvement in depressed mood among epileptic patients undergoing VNS (Elger, 2000). TEC Assessments written in 2005 and updated in 2006 concluded that evidence was insufficient to permit conclusions about the effect of VNS therapy on depression (BCBSA TEC, 2005; BCBSA TEC 2006). The available evidence for these TEC Assessments included study groups assembled by the manufacturer of the device (Cyberonics) and have since been reported on in various publications (George et al, 2005; Rush et al, 2005). Analyses from these study groups were presented for Food and Drug Administration review, and consisted of a case series of 60 patients receiving VNS (study D-01), a short-term (ie, 3-month) sham-controlled randomized trial of 221 patients (study D-02), and an observational study comparing 205 patients on VNS therapy with 124 patients receiving ongoing treatment for depression (study D-04) (FDA, 2005). Patients who responded to sham treatment in the short-term RCT (»10%) were excluded from the long-term observational study.
 
The primary outcome evaluated was the relief of depression symptoms that can usually be assessed by any one of many different depression symptom rating scales. A 50% reduction from baseline score is considered to be a reasonable measure of treatment response. Improvement in depression symptoms may allow reduction of pharmacologic therapy for depression, with a reduction in adverse events related to that form of treatment. In the studies evaluating VNS therapy, the four most common instruments used were the Hamilton Rating Scale for Depression, Clinical Global Impression, Montgomery and Asberg Depression Rating Scale, and the Inventory of Depressive Symptomatology (IDS).
 
Several case series published before the randomized trial showed rates of improvement with VNS, as measured by a 50% improvement in depression score, of 31% at 10 weeks to greater than 40% at 1 to 2 years, but there were some losses to follow-up (Marangell, 2002; Rush, 2000; Sackeim, 2001). Natural history, placebo effects, and patient and provider expectations make it difficult to infer efficacy from case series data.
 
The randomized study (D-02) that compared VNS therapy with a sham control (implanted but inactivated VNS) showed a nonstatistically significant result for the principal outcome (Rush, 2005; FDA, 2005). Fifteen percent of VNS subjects responded vs 10% of control subjects (p=0.31). The Inventory for Depressive Symptomatology Systems Review score was considered a secondary outcome and showed a difference in outcome that was statistically significant in favor of VNS (17.4%) compared with sham treatment (7.5%; p=0.04).
 
The observational study that compared patients participating in the RCT with patients in a separately recruited control group (D-04 vs D-02, respectively) evaluated VNS therapy out to 1 year and showed a statistically significant difference in the rate of change of depression score (George, 2005; FDA, 2005). However, issues such as unmeasured differences among patients, nonconcurrent controls, differences in sites of care between VNS therapy patients and controls, and differences in concomitant therapy changes raise concern about this observational study. Analyses performed on subsets of patients cared for in the same sites, and censoring observations after treatment changes, generally showed diminished differences in apparent treatment effectiveness of VNS and almost no statistically significant differences (FDA, 2005). Patient selection for the randomized trial and the observational comparison trial may be of concern. VNS is intended for treatment-refractory depression, but the entry criteria of failure of 2 drugs and a 6-week trial of therapy might not be a strict enough definition of treatment resistance. Treatment-refractory depression should be defined by thorough psychiatric evaluation and comprehensive management. It is important to note that patients with clinically significant suicide risk were excluded from all VNS studies. Given these concerns about the quality of the observational data, these results did not provide strong evidence for the effectiveness of VNS therapy.
 
In addition to the results of the TEC Assessments, several systematic reviews and meta-analyses have assessed the role of VNS in treatment-resistant depression. A 2008 systematic review of the literature for VNS of treatment-resistant depression identified the randomized trial previously described among the 18 studies that met the study’s inclusion criteria (Daban, 2008). VNS was found to be associated with a reduction in depressive symptoms in the open-label studies. However, results from the only double-blind trial were considered inconclusive (Rush, 2005; FDA, 2005). Daban et al concluded that further clinical trials are needed to confirm efficacy of VNS in treatment-resistant depression (Daban, 2008).
 
In a meta-analysis that included 14 studies, Martin and Martin-Sanchez (2012) reported that, among the uncontrolled studies included in their analysis, 31.8% of subjects responded to VNS treatment (Martin, 2012). However, results from a meta-regression to predict each study’s effect size suggested that 84% of the observed variation across studies was explained by baseline depression severity. Berry et al (Berry, 2013) reported on results from a meta-analysis of 6 industry-sponsored studies of safety and efficacy for VNS in treatment-resistant depression, which included the D-01, D-02, D-03 (Bajbouj, 2010), D-04, and D-21 (Aaronson, 2013) study results. Also, the meta-analysis used data from a registry of patients with treatment-resistant depression (335 patients receiving VNS plus treatment as usual and 301 patients receiving treatment as usual only) that were unpublished at the time of the meta-analysis publication (NCT00320372). The authors reported that adjunctive VNS was associated with a greater likelihood of treatment response (odds ratio, 3.19; 95% CI, 2.12 to 4.66). However, the meta-analysis did not have systematic study selection criteria, limiting the conclusions that can be drawn from it.
 
Liu et al conducted a systematic review of brain stimulation treatments, including deep brain stimulation, electroconvulsive therapy, transcranial magnetic stimulation, and VNS, for mental illnesses other than nonpsychotic unipolar depression in adults ages 65 years or older (Liu, 2014). Reviewers identified 2 small studies that evaluated the effect of VNS on cognition in patients with Alzheimer disease, one with 10 subjects and the other with 17 subjects, which were mixed in demonstrating clinical improvements.
 
Aaronson et al reported on results from an active-controlled trial in which 331 patients with a history of chronic or recurrent bipolar disorder or major depressive disorder, with a current diagnosis of a major depressive episode, were randomized to 1 of 3 VNS current doses (high, medium, low) (Aaronson, 2013). Patients had a history of failure to respond to at least 4 adequate dose/duration of antidepressant treatment trials from at least 2 different treatment categories. After 22 weeks, the current dose could be adjusted in any of the groups. At follow-up visits at weeks 10, 14, 18, and 22 after enrollment, there were no statistically significant differences between the dose groups for the study’s primary outcome, change in IDS score from baseline. However, mean IDS scores improved significantly for each group from baseline to the 22-week follow-up. At 50-week follow-up, there were no significant differences between the treatment dose groups for any of the depression scores used. Most patients completed the study; however, there was a high rate of reported adverse events, including voice alteration in 72.2%, dyspnea in 32.3%, and pain in 31.7%. Interpretation of the IDS improvement over time is limited by the lack of a no-treatment control group. Approximately 20% of the patients included had a history of bipolar disorder; as such, the results might not be representative of most patients with treatment-resistant unipolar depression.
 
Other case series do not substantially strengthen the evidence supporting VNS. A case series by Bajbouj et al, which followed patients for 2 years, showed that 53.1% (26/49) met criteria for a treatment response and 38.9% (19/49) met criteria for remission (Bajbouj, 2010). A small 2008 study of 9 patients with rapid-cycling bipolar disorder showed improvements in several depression rating scales over 40 weeks of observation (Marangell, 2008). Another case series, by Cristancho et al, which followed patients for 1 year, showed that 4 of 15 responded and 1 of 15 remitted according to the principal response criteria.55 In a 2014 case series that included 27 patients with treatment-resistant depression, 5 patients demonstrated complete remission after 1 year, and 6 patients were considered responders (Tisi, 2014).
Adverse events of VNS therapy included voice alteration, headache, neck pain, and cough, which are known from prior experience with VNS therapy for seizures. Regarding specific concerns for depressed patients (e.g., those with mania, hypomania, suicide, or worsening depression), there does not appear to be a greater risk of these events during VNS therapy (FDA, 2005).
 
Section Summary: Treatment-Resistant Depression
There is an RCT evaluating the efficacy of VNS for treatment-resistant depression. This trial reported only short-term results and found no significant improvement in the primary outcome with VNS. Other available studies, which include nonrandomized comparative studies and case series, are limited by relatively small sample sizes and the potential for selection bias; the case series are further limited by the lack of control groups. Given the limitations of this literature, combined with the lack of substantial new clinical trials, the scientific evidence is considered to be insufficient to permit conclusions on the effect of this technology on major depression.
 
Other Conditions
Treatment of Chronic Heart Failure
VNS has been investigated for the treatment of chronic heart failure in case series. A 2011 phase 2 case series of VNS therapy for chronic heart failure reported improvements in New York Heart Association class quality of life, 6-minute walk test, and left ventricular (LV) ejection fraction (De Ferrari, 2011). The ANTHEM-HF trial (2014) is another case series, but in it, patients were randomized to right- or left-sided vagus nerve implantation (but without a control group) (Premchand, 2014). Overall, from baseline to 6-month follow-up, a number of measures were improved: LV ejection fraction improved by 4.5% (95% CI, 2.4% to 6.6%); LV end systolic volume improved by -4.1 mL (95% CI, -9.0 to 0.8 mL); LV end-diastolic diameter improved by -1.7 mm (95% CI, -2.8 to -0.7 mm); heart rate variability improved by 17 ms (95% CI, 6.5 to 28 ms); and 6-minute walk distance improved by 56 meters (95% CI, 37 to 75 meters).
 
Zannad et al reported on results from NECTAR-HF, a randomized, sham-controlled trial, with outcomes from VNS in patients with severe LV dysfunction despite optimal medical therapy (Zannad, 2015). Ninety-six patients were implanted with a vagal nerve stimulator and randomized in a 2:1 manner to active therapy (VNS ON) or control (VNS OFF) for 6 months. Programming of the generator was performed by a physician unblinded to treatment assignment, while all other investigators and site study staff involved in the end point data collection were blinded to randomization. Sixty-three patients were randomized to the intervention, of whom 59 had paired pre-post data available, while 32 were randomized to control, of whom 28 had paired data available. The analysis was a modified intention-to-treat. For the primary end point of change in LV end-diastolic diameter from baseline to 6 months, there were no significant differences between groups (p=0.60 between-group difference in LV end-diastolic diameter change). Other secondary efficacy end points related to LV remodeling parameters (ie, LV function and circulating biomarkers of heart failure) did not differ between groups, with the exception of 36-Item Short-Form Health Survey Physical Component Summary score, which showed greater improvement in the VNS ON group than in the control group (from 36.3 to 41.2 in the VNS ON group vs from 37.7 to 38.4 in the control group; p=0.02). Subject blinding was found to be imperfect, which might have biased the subjective outcome data reporting.
 
Treatment of Upper-Limb Impairment due to Stroke
Dawson et al conducted a randomized pilot trial of VNS in patients with upper-limb dysfunction after ischemic stroke (Dawson, 2016). Twenty-one subjects were randomized to VNS plus rehabilitation or rehabilitation alone. The mean change in the outcome as assessed by a functional assessment score was +8.7 in the VNS group and +3.0 in the control group (p=0.064). Six patients in the VNS group achieved a clinically meaningful response and 4 in the control group (p=0.17).
 
Essential Tremor, Headache, Fibromyalgia, Tinnitus, and Autism
VNS has been investigated with small pilot studies or studies evaluating the mechanism of disease for several conditions. These conditions include essential tremor (Handforth, 2003), fibromyalgia (Lange, 2011), headaches (Mauskop, 2005; Cecchini, 2009), and tinnitus (De Ridder, 2014). The utility of VNS added to behavioral management of autism and autism spectrum disorders has been posited, but there are no RCTs (EngineerCT, 2017). None of these studies are sufficient to draw conclusions on the effect of VNS on these conditions.
 
Section Summary: Other Conditions
In other conditions evaluated with RCTs (heart failure, upper-limb impairment), the trials failed to show the efficacy of VNS for the primary outcome. Other conditions (essential tremor, headache, fibromyalgia, tinnitus, autism) have only been investigated with case series, which are not sufficient to draw conclusions on the effect of VNS.
 
Transcutaneous VNS
Only conditions for which there is at least 1 RCT assessing the use of transcutaneous VNS (t-VNS) are discussed because case series are inadequate to determine the effect of the technology.
 
Episodic Cluster Headaches
Goadsby et al reported on the results of randomized, double-blind, sham-controlled study (ACT2) for the treatment of cluster headache attacks (Goadsby, 2017). Ninety-two patients with cluster headaches were randomized to t-VNS (described in this response as noninvasive VNS) or sham treatment. Patients were further identified as having episodic cluster headaches or chronic cluster headaches and randomized at approximately 1:1 to the t-VNS and sham treatment groups. The primary efficacy end point was the ability to achieve pain-free status within 15 minutes of initiation of treatment without use of rescue treatment. There was no difference between t-VNS-treated and sham-treated patients in the overall cluster headache study population. Subgroup analysis of the chronic cluster headache population showed no differences between t-VNS-treated and sham-treated patients. For the episodic cluster headaches subgroup, t-VNS demonstrated a 48% response rate compared with 6% response rate for sham-treated (p<0.01).
 
Silberstein et al reported on the results of a randomized, double-blind, sham-controlled study (ACT1) of cluster headache attacks ( Silberstein, 2016). One hundred fifty patients with cluster headaches were randomized to t-VNS or sham treatment. Patients were further identified as having episodic cluster headaches or chronic cluster headaches and randomized at approximately 1:1 to the t-VNS and sham treatment groups. The primary end point was response rate defined as the ability to achieve pain-free status within 15 minutes of initiation of treatment without rescue medication use through 60 minutes. There were no differences between t-VNS-treated and sham-treated patients in the overall cluster headache study population. Subgroup analysis of the chronic cluster headache population showed no differences between t-VNS-treated and sham-treated patients. For the episodic cluster headache subgroup, t-VNS demonstrated a 34.2% response rate compared with 10.6% response rate for sham-treated (p=0.008).
 
Gaul et al reported on the results of a randomized open-label study of t-VNS for the treatment of chronic cluster headache (Gaul, 2016). Forty-eight patients with chronic cluster headache were randomized to t-VNS or individualized standard of care. Transcutaneous VNS was to be used twice daily with the option of additional treatment during headaches. At 4 weeks, the t-VNS group had a greater reduction in the number of headaches than the control group, resulting in a mean therapeutic gain of 3.9 fewer headaches per week (p=0.02). Regarding response rate, defined as a 50% or more reduction in headaches, the t-VNS group had a 40% response rate, and the control group had an 8.3% response rate (p<0.001). The study lacked a sham placebo control group, which might have resulted in placebo response in the t-VNS group.
 
Subsection Summary: Transcutaneous VNS for Episodic Cluster Headaches
Transcutaneous (or noninvasive) VNS has been investigated for episodic cluster headaches in 3 RCTs. One RCT assessing cluster headache showed a reduction in headache frequency but did not have a sham treatment group. Two randomized, double-blind, sham-controlled studies (ACT1 and ACT2) showed efficacy in achieving pain-free status within 15 minutes of treatment with t-VNS. However, the ACT1 and ACT2 studies had small episodic cluster headache subgroups of 85 (38 treated, 45 sham) and 27 (14 treated, 13 sham) respectively. Additional studies with larger cohorts of patients with episodic cluster headache are required given the small sample sizes evaluated in these trials.
 
Other Neurologic, Psychiatric, or Metabolic Disorders
Epilepsy
Aihua et al reported on results from a series of 60 patients with pharmaco-resistant epilepsy treated with a t-VNS device, who were randomized to stimulation over the earlobe (control group) or the Ramsay-Hunt zone (treatment group), which includes the external auditory canal and the conchal cavity and is considered to be the somatic sensory territory of the vagus nerve (Aihua, 2014). Thirty patients were randomized to each group; 4 subjects from the treatment group were excluded from analysis due to loss to follow-up (n=3) or adverse events (n=1), while 9 subjects from the control group were excluded from analysis due to loss to follow-up (n=2) or increase or lack of decrease in seizures or other reasons (n=7). In the treatment group, compared with baseline, the median monthly seizure frequency was significantly reduced after 6 months (5.5 months vs 6.0 months; p<0.001) and 12 months (4.0 months vs 6.0 months; p<0.001) of t-VNS therapy. At 12-month follow-up, t-VNS group subjects had a significantly lower median monthly seizure frequency compared with the control group (4.0 months vs 8.0 months; p<0.001).
 
Two small case series identified used a t-VNS device for treatment of medication-refractory seizures. In a small case series of 10 patients with treatment-resistant epilepsy, Stefan et al reported that 3 patients withdrew from the study, while 5 of 7 patients reported a reduction in seizure frequency (Stefan, 2012). In another small case series, He et al reported that, among 14 pediatric patients with intractable epilepsy who were treated with bilateral t-VNS, of the 13 patients who completed follow-up, the mean reduction in self-reported seizure frequency was 31.8% after 8 weeks, 54.1% from week 9 to 16, and 54.2% from week 17 to 24 (He, 2013).
 
Psychiatric Disorders
Hein et al reported on results of 2 pilot RCTs of a t-VNS device for the treatment of depression, one of which included 22 subjects and another assessed 15 subjects (Hein, 2013). In the first study, 11 subjects were randomized to active or sham t-VNS. At 2-week follow-up, Beck Depression Inventory (BDI) self-rating scores in the active stimulation group decreased from 27.0 to 14.0 points (p<0.001), while the sham-stimulated patients did not show significant reductions in BDI scores (31.0 to 25.8 points). In the second study, 7 patients were randomized to active t-VNS, and 8 patients were randomized to sham t-VNS. In this study, BDI self-rating scores in the active stimulation group decreased from 29.4 to 17.4 points (p<0.05) after 2 weeks, while the sham-stimulated patients did not show a significant change in BDI scores (28.6 to 25.4 points). The authors did not report direct comparisons in BDI change scores between the sham- and active-stimulation groups.
 
Hasan et al reported on a randomized trial of t-VNS for the treatment of schizophrenia (Hasan, 2015). Twenty patients were assigned to active t-VNS or sham treatment for 12 weeks. There was no statistically significant difference in the improvement of schizophrenia status during the observation period.
 
Shiozawa et al conducted a systematic review of studies evaluating the evidence related to transcutaneous stimulation of the trigeminal or vagus nerve for psychiatric disorders (Shiozawa, 2014). They found 4 studies addressing t-VNS for psychiatric disorders (total N=84 subjects). Three of the 4 studies evaluated physiologic parameters in healthy patients, and one evaluated pharmaco-resistant epilepsy (Stefan, 2012). Reviewers also included a fifth study in a data table, although not in their text or a reference list (Hein, 2013). Overall, the studies assessed were limited by small size and poor generalizability.
 
Other Headaches
Goadsby et al reported on results from an open-label pilot study of t-VNS for the treatment of a migraine with or without aura (Goadsby, 2014). Eighty migraine attacks were self-treated by 27 patients, of an initial sample of 30 patients (2 patients treated no migraine attacks with the device, 1 patient treated only an aura). Of 54 moderate or severe attacks treated, 12 subjects (22%) were pain-free at 2 hours posttreatment. Thirteen subjects reported adverse events, which were all considered mild or moderate.
Tso et al (2017) evaluated the records of 15 patients treated with a t-VNS device (gammaCore) for paroxysmal hemicrania (n=6) or hemicrania continua (n=9) as primary treatment or as an adjunct to indomethacin (Tso, 2017). Symptom-related outcomes included reduction of pain severity and reduced frequency of attacks: for the first, 7 hemicrania continua patients saw improvement with t-VNS therapy, as did 3 patients with paroxysmal hemicranias. The frequency of attacks was reduced for 2 hemicrania continua patients and 2 paroxysmal hemicranias patients. Some adverse events were reported in all patients, although not detailed.
 
Impaired Glucose Tolerance
Huang et al reported on results of a pilot RCT of a t-VNS device that provides stimulation to the auricle for the treatment of impaired glucose tolerance (Huang, 2014). The trial included 70 patients with impaired glucose tolerance who were randomized to active or sham t-VNS, along with 30 controls who received no t-VNS treatment. After 12 weeks of treatment, patients who received active t-VNS were reported to have significantly lower 2-hour glucose tolerance test results than those who received sham t-VNS (7.5 mmol/L vs 8 mmol/L; p=0.004).
 
Section Summary: Transcutaneous VNS for Other Neurologic, Psychiatric, or Metabolic Disorders
Transcutaneous VNS has been investigated in small randomized trials for several conditions. Some evidence for the efficacy of t-VNS for epilepsy comes from a small RCT, which reported lower seizure rates for active t-VNS-treated patients than for sham controls; however, the high dropout rates in this trial are problematic. In the study of depression, a small RCT that compared treatment using t-VNS with sham stimulation demonstrated some improvements in depression scores with t-VNS; however, the lack of comparisons between groups limits conclusions that might be drawn. A sham-controlled pilot randomized trial for impaired glucose tolerance showed some effect on glucose tolerance tests.
 
SUMMARY OF EVIDENCE
 
Vagus Nerve Stimulation
For individuals who have seizures refractory to medical treatment who receive VNS, the evidence includes RCTs and multiple observational studies. Relevant outcomes are symptoms, change in disease status, and functional outcomes. The RCTs have reported significant reductions in seizure frequency for patients with partial-onset seizures. The uncontrolled studies have consistently reported large reductions in a broader range of seizure types in both adults and children. The evidence is sufficient to determine that the technology results in a meaningful improvement in the net health outcome.
 
For individuals who have treatment-resistant depression who receive VNS, the evidence includes an RCT, nonrandomized comparative studies, and case series. Relevant outcomes are symptoms, change in disease status, and functional outcomes. The RCT only reported short-term results and found no significant improvement in the primary outcome. Other available studies are limited by small sample sizes, potential selection bias, and lack of a control group in the case series. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
Other Conditions
For individuals who have chronic heart failure who receive VNS, the evidence includes RCTs and case series. Relevant outcomes are symptoms, change in disease status, and functional outcomes. The RCTs evaluating chronic heart failure did not show significant improvements in the primary outcomes. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
For individuals who have upper-limb impairment due to stroke who receive VNS, the evidence includes a single pilot study. Relevant outcomes are symptoms, change in disease status, and functional outcomes. This pilot study has provided preliminary support for improvement in functional outcomes. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
For individuals who have other neurologic conditions (e.g., essential tremor, headache, fibromyalgia, tinnitus, autism) who receive VNS, the evidence includes case series. Relevant outcomes are symptoms, change in disease status, and functional outcomes. Case series are insufficient to draw conclusions regarding efficacy. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
Transcutaneous Vagus Nerve Stimulation
For individuals with episodic cluster headaches who receive transcutaneous VNS, the evidence includes 3 RCTs. One RCT for a cluster headache showed a reduction in headache frequency but did not include a sham treatment group. Two randomized, double-blind, sham-controlled studies showed efficacy of achieving pain-free status within 15 minutes of treatment with noninvasive VNS in patients with episodic cluster headaches but not in patients with chronic cluster headaches. The RCTs for episodic cluster headaches are promising; however, additional studies with larger relevant populations are required to establish the treatment efficacy. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
For individuals who have other neurologic, psychiatric, or metabolic disorders (e.g., epilepsy, depression, schizophrenia, noncluster headache, impaired glucose tolerance) who receive transcutaneous VNS, the evidence includes RCTs and case series for some of the conditions. Relevant outcomes are symptoms, change in disease status, and functional outcomes. The RCTs are all small and have various methodologic problems. None showed definitive efficacy of transcutaneous VNS in improving patient outcomes. The evidence is insufficient to determine the effects of the technology on health outcomes.
 
PRACTICE GUIDELINES AND POSITION STATEMENTS
 
American Academy of Neurology
In 1999, the American Academy of Neurology released a consensus statement on the use of vagus nerve stimulation (VNS) in adults, which stated: “VNS is indicated for adults and adolescents over 12 years of age with medically intractable partial seizures who are not candidates for potentially curative surgical resections, such as lesionectomies or mesial temporal lobectomies”(Fisher,1999). The Academy updated these guidelines in 2013, stating: “VNS may be considered for seizures in children, for LGS [Lennox-Gastaut syndrome]-associated seizures, and for improving mood in adults with epilepsy (Level C). VNS may be considered to have improved efficacy over time (Level C)” (Morris, 2013). An update is reported to be in progress at the time of this review.
 
American Psychiatric Association
The American Psychiatric Association guidelines for the treatment of major depressive disorder in adults, updated in 2010, included the following statement on the use of VNS: “Vagus nerve stimulation (VNS) may be an additional option for individuals who have not responded to at least four adequate trials of antidepressant treatment, including ECT [electroconvulsive therapy],” with a level of evidence III (APA, 2010).
 
European Headache Federation
In 2013, the European Headache Federation issued a consensus statement on neuromodulation treatments for chronic headaches, which made the following statement about the use of VNS: “Due to the lack of evidence, VNS should only be employed in chronic headache sufferers using a randomized, placebo controlled trial design” (Martelletti, 2013).
 
2019 Update
A literature search was conducted through July 2019.  There was no new information identified that would prompt a change in the coverage statement.  
 
2020 Update
Annual policy review completed with a literature search using the MEDLINE database through July 2020. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Kimberley et al reported results of a randomized, pilot sham-controlled RCT in 17 patients (VNS =8 and sham VNS, n=9)) with arm weakness after ischemic stroke (Kimberly, 2018). The mean Fugl-Meyer assessment–upper extremity scores increased by 7.6 with VNS versus 5.3 points with sham at day 1 (Difference=2.3 points; 95% CI, 1.8 to 6.4; p=0.20) and 9.5 points with VNS versus 3.8 with sham at day 90 (Difference=5.7 points; 95% CI, 1.4 to 11.5; p=0.055). A Fugl-Meyer assessment–upper extremity change 6 points was defined as response; the response rate at day 90 was 88% with VNS versus 33% with sham (p<0.05). There were 3 serious adverse events related to surgery: wound infection, shortness of breath and dysphagia, and hoarseness because of vocal cord palsy.
 
de Coo et al combined the data from ACT1 and ACT2 meta-analytically for the 2 primary outcomes reported in the 2 studies (de Coo, 2019). The authors reported an interaction between treatment group and cluster headache subtype in the pooled analysis (p<0.05 for both outcomes).
 
The PREMIUM trial was a phase 3, multicenter, sham-controlled RCT conducted in several European countries including patients who experienced 5–12 migraine days per month (Diener, 2019). The study included a 4-week run-in period during which no treatment was administered; 477 participants entered the run-in. The criteria to remain eligible after run-in were not described in the publication. After run-in, 341 participants were randomized (nVNS, n=169 or sham, n=172) to a 12-week double-blind treatment period followed by a 24-week open-label period of nVNS. Patients administered two 120-second stimulations bilaterally to the neck with gammaCore, 3 times daily. NVNS was not statistically significantly superior to sham. with respect to the outcomes of reduction of at least 50% in migraine days from baseline to the last 4 weeks, reduction in number of migraine days from baseline to the last 4 weeks or acute medication days in the intention-to-treat population.
 
2021 Update
Annual policy review completed with a literature search using the MEDLINE database through July 2021. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Bottomley et al reported results of a systematic review and meta-analysis of 2 RCTs (Rush et al [2005] and Aaronson et al [2013]), 16 single-arm and 4 nonrandomized comparative studies (Bottomley, 2019). The meta-analysis calculated overall pooled effect estimates for VNS and treatment-as-usual groups, respectively, but did not perform quantitative analysis of comparative treatment effects. Thus, this meta-analysis provides insufficient evidence to permit comparisons between VNS and the control groups.
 
Aaronson et al reported on results from the FDA required post-marketing surveillance study, which was a 5-year, prospective, open-label, nonrandomized observational study of the Treatment-Resistant Depression Registry (Aaronson, 2017). The study compared treatment as usual, with or without adjunctive VNS. It was conducted at 61 sites in the United States and included 795 patients (VNS n=494, no VNS n=301) who were experiencing a major depressive episode (unipolar or bipolar depression) of at least 2 years’ duration or had a history of 3 or more depressive episodes (including the current episode), and who had failed at least 4 prior depression treatments (including electroconvulsive therapy). Study treatment was patient-selected and/or assigned on an individualized basis at the discretion of the study site. The exception was for a subset of 159 (32%) of VNS patients who were rolled over from the D-21 study (Aaronson, 2013). The primary efficacy outcome was the cumulative first-time 5-year response rate, defined as at least a 50% reduction in the Montgomery-Asberg Depression Rating Scale (MADRS) score at any post-baseline visit. Due to its nonrandomized design, several significant between-groups differences were noted at baseline, including that the VNS group had a higher rate of past treatment with ECT (57% vs. 40%; p<.001), a higher number of prior failed depression treatments (8.2 vs. 7.3; p=.010) more psychiatric hospitalizations within the 5 years before enrollment (3.0 vs. 1.9; p<.001) and lifetime suicide attempts (1.8 vs. 1.2; p=.02), and a higher mean MADRS score (33.1 vs. 29.3; p<.001). The propensity score method was used to adjust for these baseline imbalances. Clinical outcomes were significantly improved in the VNS groups, including higher cumulative first-time response (67.6% vs. 40.9%; p<.001) and cumulative first-time remission (MADRS total score 9 at any postbaseline visit, 43.3% vs. 25.7%; p<0.001). The VNS arm also demonstrated a significantly greater reduction in suicidality on 2 of 3 different measures: Quick Inventory of Depressive Symptomatology–Self Report (QIDS-SR) item 12 (OR=2.11; 95% CI, 1.28 to 3.48), investigator-completed suicidality assessment (OR=2.04; 95% CI, 1.08 to 3.86), but not MADRS item 10 (OR=1.67; 95% CI, 0.98 to 2.83). There was no significant difference between the VNS and no VNS groups in completed suicides (1.01 per 1,000 person-years [95% CI=0.11 to 3.64] and 2.20 per 1,000 person-years [95% CI=0.24 to 7.79], respectively). Important limitations of the study include lack of a sham condition and the potential for bias due to confounding from unrestricted and uncontrolled concomitant treatments and bias in outcome measurement, which was unblinded. Additionally, other important outcomes such as quality of life and relapse were not reported.
 
McAllister-Williams et al reported on results of a subgroup of 156 participants with treatment-resistant bipolar depression from the above-described FDA-required post-marketing surveillance study (McAllister-Williams, 2020; Aaronson, 2017). Compared to the overall population in the primary study, cumulative first-time response rates were similar in this bipolar depression subgroup (63% vs. 39%; p not reported). Median time-to-initial response was not significantly different between groups (13.7 vs. 42.1 months; Hazard Ratio [HR]=1.7; 95% CI, 1 to 2.7). Median time-to-relapse from initial response in the first year was also not significantly different between groups (15.2 vs. 7.6 months; HR=0.7; 95% CI, 0.3 to 1.4). Based on MADRS item 10, the mean reduction in suicidality score across the study visits was reportedly significantly greater in the VNS group than in the no VNS group (p<.001 as per F-test). However, the validity of this finding is unclear as by 60 months, it excluded data from an unacceptably high (n=100, 64%) and imbalanced (59% in VNS group vs. 73% in no VNS group) number of patients with unavailable suicidality data. It was additionally subject to the same important limitations as described above for the primary study.
 
Wu et al reported results of a systematic review and meta-analysis of 3 RCT’s (N=280, range n=60 to 144) of transcutaneous VNS for the treatment of drug-resistant epilepsy (Aihua, 2014; Bauer, 2016; Rong, 2014; Wu, 2020). All treatment groups underwent a cymba conchae stimulus at a frequency of 20–30-Hz. The control groups received various kinds of sham stimulation at a frequency of 1 HZ, the same frequency stimulation as treatment but at the non-auricular vagus nerve area or no stimulation. Meta-analysis of all 3 included RCTs found that seizure frequency was significantly reduced with transcutaneous VNS (Mean Difference [MD]=-3.29; 95% CI, -6.31 to -0.27). However, meta-analysis of the 2 RCTs that reported responder rates (undefined) did not find a significant difference between the transcutaneous VNS and control groups (N=238; Odds Ratio [OR]=1.47; 95% CI, 0.54 to 4.02]. All 3 RCTs assessed quality of life using the Quality of Life in Epilepsy Inventory (QOLIE)-31 scale but found no significant differences between treatment and control groups. Important limitations of the RCTs include imprecision, risk of confounding due to potentially imbalanced use of important nonprotocol interventions (ie, concomitant antiepileptic drugs), and unacceptable flaws in outcome assessment (ie, unspecified definition of response, between-group differences in measurement timing, lack of electroencephalography data).
 
Wu et al reported results of a randomized, pilot sham-controlled RCT in 21 patients (nVNS=10 and sham nVNS, n=11) with upper limb motor function impairment following subacute ischemic stroke (Wu, 2020). The mean Fugl-Meyer assessment–upper extremity scores increased by 6.90 with nVNS versus 3.18 points with sham after 15 days of intervention (Difference= -3.72 points; 95% CI, 5.12 to -2.32; p.001). The improvement in the mean Fugl-Meyer assessment–upper extremity scores remained significantly higher at both the 4-week (+7.70 vs. +3.36; p.001) and the 12-week (+7.40 vs. +4.18; p=.038) follow-ups. There was only 1 adverse event noted, which was that 1 patient in the nVNS group developed skin redness at an electrode point of contact.
 
Kutlu et al (2020) reported results of an RCT that compared a home-based exercise treatment program with or without auricular VNS in 60 female patients in Turkey with fibromyalgia syndrome (auricular VNS n=30 and no auricular VNS n=30) (Kutlu, 2020). The VNS was delivered at Beykoz Public Hospital’s Department of Physical Therapy and Rehabilitation in 30-minute sessions on weekdays for 4 weeks. The home-based exercise program consisted of strengthening, stretching, isometric, and posture exercises that targeted the body and upper and lower extremities. When added to exercise, auricular VNS did not significantly improve mean scores on the Fibromyalgia Impact Questionnaire (37.27 vs. 41.93; p=.378) or on any 36-Item Short Form Health Survey subscales (eg, Physical Function: 80.00 vs. 85.00; p=.167). An important limitation of this RCT is the lack of a sham control group.
 
In 2020, the NICE published a Interventional Procedure Overview on implanted vagus nerve stimulation for treatment-resistant depression (IPG679) (NICE, 2020). The guidance states: "Evidence on the safety of implanted vagus nerve stimulation for treatment-resistant depression raises no major safety concerns, but there are frequent, well-recognized side effects. Evidence on its efficacy is limited in quality. Therefore, this procedure should only be used with special arrangements for clinical governance, consent, and audit or research." The guidance further states that "NICE encourages further research into implanted vagus nerve stimulation for treatment-resistant depression, in the form of randomized controlled trials with a placebo or sham stimulation arm. Studies should report details of patient selection. Outcomes should include validated depression rating scales, patient-reported quality of life, time to onset of effect and duration of effect, and any changes in concurrent treatment."
 
In response to a request from LivaNova, on May 30, 2018, the Centers for Medicare & Medicaid Services (CMS) initiated its second reconsideration of its national coverage decision on VNS for Treatment Resistant Depression. Based on an internal literature review (search dates unspecified), CMS concluded that although the published evidence suggests that VNS is a promising treatment for patients with TRD, the reviewed studies have important flaws that leave uncertainty about its true benefits and harms (CMS, 2019). Thus, effective February 15, 2019, the CMS expanded Medicare coverage to "cover U.S. Food and Drug Administration approved vagus nerve stimulation (VNS) devices for treatment resistant depression (TRD) through Coverage with Evidence Development when offered in a CMS approved, double-blind, randomized, placebo-controlled trial with a follow-up duration of at least one year with the possibility of extending the study to a prospective longitudinal study when the CMS approved, double-blind, randomized placebo-controlled trial has completed enrollment, and there are positive interim findings." CMS approval of a Coverage with Evidence Development study requires answering 9 research questions specifying measurement of response, remission, harms and other health outcome variables, use of specific eligibility criteria for TRD diagnosis as described in an Agency for Healthcare Research and Quality Technology Assessment conducted by Gaynes et al, as well as 13 additional operational criteria (Gaynes, 2018). CMS has approved 1 ongoing study for Coverage with Evidence Development - A Prospective, Multi-center, Randomized Controlled Blinded Trial Demonstrating the Safety and Effectiveness of VNS Therapy® System as Adjunctive Therapy Versus a No Stimulation Control in Subjects With Treatment-Resistant Depression (RECOVER) (NCT03887715) (CMS, 2019). Conway et al have published a detailed description of the RECOVER study rationale and design (Conway, 2020).
 
2022 Update
Annual policy review completed with a literature search using the MEDLINE database through July 2022. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Sant'Anna et al conducted a systematic review and meta-analysis on clinical trials comparing VNS with medical therapy for the management of chronic heart failure with reduced ejection fraction (Sant’Anna, 2021). Four RCTs and 3 prospective studies were identified (N=1263). Only data from the 4 RCTs were included in the meta-analysis. The certainty of the evidence based on GRADE characteristics was reported as high for all outcomes. The meta-analysis found significant improvements in New York Heart Association functional class, quality of life, 6-minute walk test, and N-terminal-pro brain natriuretic peptide levels in patients treated with VNS compared to sham.
 
A follow-up analysis to ANTHEM-HF by Nearing et al evaluated outcomes of VNS at 12, 24, and 36 months (Nearing, 2021). They found that LV ejection fraction improved by 18.7% (p=.008), 19.3% (p=.04), and 34.4% (p=.009) at 12, 24, and 36 months, respectively, with high-intensity VNS. Individuals with low-intensity VNS only had significant improvement in LV ejection fraction at 24 months (12.3%; p=.04).
 
Dawson et al conducted a randomized pilot trial of VNS in patients with upper-limb dysfunction after ischemic stroke in 2016. A similar RCT with a larger patient population was conducted by the same study group in 2021 (Dawson, 2021). Patients with upper-limb dysfunction after ischemic stroke (N=106) were randomly assigned 1:1 to either VNS plus rehabilitation or rehabilitation with sham stimulation. The Fugl-Meyer Assessment-Upper Extremity score increased by 5 points in the VNS group and 2.4 points in the control group (between-group difference, 2.6; 95% CI, 1.0 to 4.2; p=.0014). Ninety days after in-clinic therapy, a clinically meaningful response was achieved in 23 (47%) of 53 patients in the VNS group versus 13 (24%) of 55 patients in the control group (between-group difference, 24%; 95% CI, 6 to 41; p=.0098). There was 1 adverse event of vocal cord paresis related to surgery in the control group.
 
2023 Update
Annual policy review completed with a literature search using the MEDLINE database through July 2023. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
Panebianco et al updated a Cochrane systematic review and meta-analysis of VNS to treat partial seizures (Panebianco, 2015). Reviewers specifically evaluated randomized, double-blind, parallel or crossover, controlled trials of VNS as add-on treatment comparing high- and low-stimulation paradigms plus VNS stimulation with no stimulation or different intervention. Five trials (N=439) compared high-frequency stimulation with low-frequency stimulation in participants ages 12 to 60 years, and another trial compared high-frequency stimulation with low-frequency stimulation in children. Risk of bias was rated as low for most domains across studies. However, none of the protocols for the included studies were available and therefore were rated as having an unclear risk of bias for selective reporting. In addition, all studies were sponsored by the manufacturers of the device. An updated Cochrane systematic review published in 2022 by the same author group did not identify any new RCTs (Panebianco,2022).
 
Ramos-Castaneda et al published a systematic review evaluating VNS on upper limb motor recovery after stroke (Ramos-Castaneda, 2022). Three of the RCTs were pooled for the analysis evaluating the role of implanted VNS. Results demonstrated that implanted VNS improved upper limb motor function based on Fugl-Meyer Assessment-Upper Extremity (FMA-UE) score when compared to control (mean difference=2.78; 95% CI, 1.38 to 4.18).
 
The PREMIUM II trial was a multicenter, sham-controlled RCT conducted in several U.S. sites and included patients who experienced 8 to 20 headache days per month with at least 5 of the days being migraine days (Najib, 2022). The study included a 4-week run-in period during which no treatment was administered (N=336). After the run-in period, 231 patients were randomly assigned to receive nVNS (n = 114) or sham (n = 117) therapy during the double-blind period and were part of the intention to treat (ITT) population (i.e., had 1 study treatment during the double-blind phase). The COVID-19 pandemic led to an early termination of this trial, therefore, the population was approximately 60% smaller than the statistical target for full power. The modified ITT (mITT) population, which included those who were at least 66% adherent to treatment during the double-blind phase, included 56 patients in the nVNS group and 57 in the sham group. Results showed that in the mITT population, nVNS was not statistically significantly superior to sham with respect to the primary outcome of reduction in the number of migraine days per month during weeks 9 through 12 (mean difference=-0.83 days; p=.2329), nor other outcomes such as mean change in the number of headache days or acute medication days. However, in the mITT population, the percentage of patients with at least a 50% reduction in the number of migraine days was significantly greater in the nVNS group (44.87%) than in the sham group (26.81%; p=.048). Furthermore, nVNS was significantly better than sham at decreasing headache impact, as measured by the Headache Impact Test-6 (HIT-6), and at decreasing migraine-related disability, as measured by the Migraine Disability Assessment Scale (MIDAS).
 
2024 Update
Annual policy review completed with a literature search using the MEDLINE database through February  2024. No new literature was identified that would prompt a change in the coverage statement. The key identified literature is summarized below.
 
A RCT published after the meta-analysis, found similar results (Yand, 2023). In total, 150 patients with drug-resistant epilepsy were randomized to tVNS (n=100) or sham VNS (n=50). The patient's current antiepileptic drugs were unchanged throughout the study. At 20 weeks of treatment, investigators found that response to treatment (experiencing 50% reduction in mean seizure frequency) was significantly higher with tVNS (44.74%) compared to sham (16.67%; p<.05). However, there were no significant differences in quality-of-life scores between groups. These results are limited by the small sample size and high dropout rate (25.3%).
 
A case series was published in patients with heart failure with preserved ejection fraction (HFpEF) or mildly reduced ejection fraction (HFmrEF), called the ANTHEM-HFpEF trial (Kumar, 2023). Fifty-two patients with HFpEF or HFmrEF, NYHA class II to III on guideline-directed medical therapy were successfully implanted with VNS therapy. At 12 months, NYHA class improved in 55% of patients (<0.0001), 6 minute walk test distance improved (mean, 300 m ± 71 at 12 mo vs 288 m ± 78 m at baseline; p<.05), and quality of life scores were improved compared to baseline (p<.0001).

CPT/HCPCS:
61885Insertion or replacement of cranial neurostimulator pulse generator or receiver, direct or inductive coupling; with connection to a single electrode array
61886Insertion or replacement of cranial neurostimulator pulse generator or receiver, direct or inductive coupling; with connection to 2 or more electrode arrays
61888Revision or removal of cranial neurostimulator pulse generator or receiver
64553Percutaneous implantation of neurostimulator electrode array; cranial nerve
64568Open implantation of cranial nerve (eg, vagus nerve) neurostimulator electrode array and pulse generator
64569Revision or replacement of cranial nerve (eg, vagus nerve) neurostimulator electrode array, including connection to existing pulse generator
64570Removal of cranial nerve (eg, vagus nerve) neurostimulator electrode array and pulse generator
95976Electronic analysis of implanted neurostimulator pulse generator/transmitter (eg, contact group[s], interleaving, amplitude, pulse width, frequency [Hz], on/off cycling, burst, magnet mode, dose lockout, patient selectable parameters, responsive neurostimulation, detection algorithms, closed loop parameters, and passive parameters) by physician or other qualified health care professional; with simple cranial nerve neurostimulator pulse generator/transmitter programming by physician or other qualified health care professional
95977Electronic analysis of implanted neurostimulator pulse generator/transmitter (eg, contact group[s], interleaving, amplitude, pulse width, frequency [Hz], on/off cycling, burst, magnet mode, dose lockout, patient selectable parameters, responsive neurostimulation, detection algorithms, closed loop parameters, and passive parameters) by physician or other qualified health care professional; with complex cranial nerve neurostimulator pulse generator/transmitter programming by physician or other qualified health care professional
E0735Non invasive vagus nerve stimulator
K1020Non-invasive vagus nerve stimulator
L8678Electrical stimulator supplies (external) for use with implantable neurostimulator, per month
L8679Implantable neurostimulator, pulse generator, any type
L8680Implantable neurostimulator electrode, each
L8681Patient programmer (external) for use with implantable programmable neurostimulator pulse generator, replacement only
L8682Implantable neurostimulator radiofrequency receiver
L8683Radiofrequency transmitter (external) for use with implantable neurostimulator radiofrequency receiver
L8684Radiofrequency transmitter (external) for use with implantable sacral root neurostimulator receiver for bowel and bladder management, replacement
L8685Implantable neurostimulator pulse generator, single array, rechargeable, includes extension
L8686Implantable neurostimulator pulse generator, single array, non rechargeable, includes extension
L8687Implantable neurostimulator pulse generator, dual array, rechargeable, includes extension
L8688Implantable neurostimulator pulse generator, dual array, non rechargeable, includes extension
L8689External recharging system for battery (internal) for use with implantable neurostimulator, replacement only

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