Transvenous phrenic nerve stimulation for treating central sleep apnea may regulate sleep microstructure.

STUDY OBJECTIVES: To assess the impact of transvenous phrenic nerve stimulation (TPNS) on non-rapid eye movement sleep microstructure quantified by cyclic alternating pattern (CAP) in individuals with central sleep apnea (CSA). METHODS: We analyzed baseline and 6-month follow-up overnight polysomnograms (PSG) in 134 CSA patients enrolled in the remede System Pivotal Trial implanted with TPNS randomized (1:1) to neurostimulation (treatment group) or no stimulation (control group). Differences in CAP rate, A1 index, and A2+A3 index between study arms at follow-up were assessed using Analysis of Covariance adjusted for baseline values. RESULTS: On follow-up PSG, the treatment group showed a decrease in the frequency of A2+A3 phases compared to controls (-5.86 ± 11.82 vs. 0.67 ± 15.25, p = 0.006), while the frequency of A1 phases increased more in the treatment group (2.57 ± 11.67 vs. -2.47 ± 10.60, p = 0.011). The change in CAP rate at follow-up was comparable between study arms. CONCLUSIONS: TPNS treatment for central sleep apnea may affect sleep microstructure. Brief phases of rapid cortical activity appear to be replaced by short phases of slower cortical activity, which may promote sleep continuity. Further investigations are warranted to elucidate the mechanisms underlying the effect of TPNS on CAP.

Transvenous phrenic nerve stimulation is associated with normalization of nocturnal heart rate perturbations in patients with central sleep apnea.

STUDY OBJECTIVES: To determine the effect of transvenous phrenic nerve stimulation (TPNS) on nocturnal heart rate perturbations in patients with CSA. METHODS: In this ancillary study of the remede System Pivotal Trial, we analyzed electrocardiograms from baseline and follow-up overnight polysomnograms (PSG) in 48 CSA patients in sinus rhythm with implanted TPNS randomized to stimulation (treatment group; TPNS on) or no stimulation (control group; TPNS off). We quantified heart rate variability in the time and frequency domain. Mean change from baseline and standard error is provided. RESULTS: TPNS titrated to reduce respiratory events is associated with reduced cyclical heart rate variations in the very low-frequency domain across REM (VLFI: 4.12 ± 0.79% vs. 6.87 ± 0.82%, p = 0.02) and NREM sleep (VLFI: 5.05 ± 0.68% vs. 6.74 ± 0.70%, p = 0.08) compared to the control group. Further, low-frequency oscillations were reduced in the treatment arm in REM (LFn: 0.67 ± 0.03 n.u. vs. 0.77 ± 0.03 n.u., p = 0.02) and NREM sleep (LFn: 0.70 ± 0.02 n.u. vs. 0.76 ± 0.02 n.u., p = 0.03). CONCLUSION: In adult patients with moderate to severe central sleep apnea, transvenous phrenic nerve stimulation reduces respiratory events and is associated with the normalization of nocturnal heart rate perturbations. Long-term follow-up studies could establish whether the reduction in heart rate perturbation by TPNS also translates into cardiovascular mortality reduction. CLINICAL TRIAL: A Randomized Trial Evaluating the Safety and Effectiveness of the remede® System in Patients With Central Sleep Apnea, ClinicalTrials.gov, NCT01816776.

Phrenic nerve stimulation for the treatment of central sleep apnea in patients with heart failure.

OBJECTIVE: Central sleep apnea (CSA) is associated with increased morbidity and mortality in patients with heart failure (HF). We aimed to explore the effectiveness of phrenic nerve stimulation (PNS) on CSA in patients with HF. METHODS: This was a prospective and non-randomized study. The stimulation lead was inserted into the right brachiocephalic vein and attached to a proprietary neurostimulator. Monitoring was conducted during the implantation process, and all individuals underwent two-night polysomnography. RESULTS: A total of nine subjects with HF and CSA were enrolled in our center. There was a significant decrease in the apnea-hypopnea index (41 ± 18 vs 29 ± 25, p = 0.02) and an increase in mean arterial oxygen saturation (SaO2) (93% ± 1% vs 95% ± 2%, p = 0.03) after PNS treatment. We did not observe any significant differences of oxygen desaturation index (ODI) and SaO2 < 90% (T90) following PNS. Unilateral phrenic nerve stimulation might also categorically improve the severity of sleep apnea. CONCLUSION: In our non-randomized study, PNS may serve as a therapeutic approach for CSA in patients with HF.

Design of the remede System Therapy (reST) study: A prospective non-randomized post-market study collecting clinical data on safety and effectiveness of the remede system for the treatment of central sleep apnea.

BACKGROUND: Central sleep apnea (CSA) is a disorder defined by lack of respiratory drive from the brain stem on breathing efforts. There is a lack of established therapies for CSA and most available therapies are limited by poor patient adherence, limited randomized controlled studies, and potentially adverse cardiovascular effects. The remede System (ZOLL Respicardia, Inc., Minnetonka, Minnesota) uses transvenous phrenic nerve stimulation to stimulate the diaphragm, thereby restoring a more normal breathing pattern throughout the sleep period. METHODS: The remede System Therapy (reST) Study is a prospective non-randomized multicenter international study evaluating long-term safety and effectiveness of the remede System in the post-market setting. Up to 500 adult patients with moderate to severe CSA will be enrolled and followed up to 5 years at approximately 50 sites in the United States and Europe. Safety objectives include evaluation of adverse events related to the implant procedure, device or delivered therapy, death, and hospitalizations. Effectiveness endpoints include assessment of changes in sleep-disordered breathing metrics from polysomnograms and home sleep tests, changes in daytime sleepiness using the Epworth Sleepiness Scale, and changes in QoL using the PROMIS-29 and Patient Global Assessment questionnaires. The subgroup of patients with heart failure will undergo additional assessments including echocardiography to assess cardiac reverse remodeling, 6-min walk distance, QoL assessment by Kansas City Cardiomyopathy Questionnaire and measurement of biomarkers. CONCLUSION: This will be the largest prospective study evaluating long-term safety and effectiveness of transvenous phrenic nerve stimulation for the treatment of moderate to severe CSA in adult patients.

Transvenous Phrenic Nerve Stimulation for Central Sleep Apnea.

RespiCardia remede System (Minnetonka, MN 2017), a transvenous phrenic nerve stimulator, is indicated to treat central sleep apnea (CSA) by stimulating the phrenic nerve to cause diaphragmatic contraction to restore normal breathing during sleep. CSA is associated with decreased patient quality of life and worsens cardiovascular outcomes. Systematic review was conducted according to the Preferred Reporting of Systematic Reviews and Meta-Analysis guidelines. PubMed/MEDLINE, Cochrane, EBSCO CINAHL, and Ovid databases were queried by 2 independent reviewers for English-language studies published between 2000 and 2021. The initial search screened for all occurrences of "remede" then was further refined to include studies evaluating use of the RespiCardia remede System as a treatment for CSA in multiple patients. A total of 124 articles were identified from the initial search results. A total of 37 articles were identified through screening of title and abstracts from initial results. Full-text review of all the articles was then completed. Of the 13 articles included, a total of 232 patients underwent device implantation. We sought to summarize the available evidence regarding patient selection for implantation, immediate and delayed complications, adherence to therapy, and polysomnographic evidence of efficacy. All 13 articles detailed significant decreases in central apnea index and many patients reported significant mild to marked improvement in quality of life. In conclusion, the remede System has been demonstrated to improve sleep and respiratory parameters, with few complications. This device demonstrates safe and effective treatment of moderate to severe CSA in adult patients, including those with heart failure.

Phrenic nerve stimulation experiences. A single centre, controlled, prospective study.

Patients with central apnoea may use electro ventilation, provided their phrenic nerves and diaphragm muscles are normal. A tendency towards better survival has been found, and both an improved quality of life and facilitated nursing have been claimed with electro ventilation compared to mechanical ventilation. The high investment for the device may form a hurdle for fund providers like our hospital administration board. We, therefore, from our first patient onwards, collected clinically meaningful data in a special register of all patients using electro ventilation and their controls on mechanical ventilation. Since 1988 172 patients left our institution dependent on a respiratory device. Of these, all 48 patients with preserved phrenic nerves chose phrenic nerve stimulation. A patient on mechanical ventilation who agreed to participate was chosen as a control (n = 44). All patients were seen at least once a year. 90 patients suffered high tetraplegia, and 2 suffered central apnoea for other reasons. There is a tendency towards better survival, and there is a lower frequency of decubital ulcers (0.02) and respiratory tract infections (p0.000) with electro than with mechanical ventilation. The frequency of respiratory infections turned out to be a better measure of the quality of respiratory care than survival. The resulting decrease in the need for airway nursing, and the reduced incidence of respiratory infections repaid the high investment in electro ventilation within one year in our setting. Informed patients prefer electro to mechanical ventilation; fund providers might also agree with this preference.

Transvenous Phrenic Nerve Stimulation for Central Sleep Apnea: Clinical and Billing Review.

Central sleep apnea (CSA) frequently coexists with heart failure and atrial fibrillation and contributes to cardiovascular disease progression and mortality. A transvenous phrenic nerve stimulation (TPNS) system has been approved for the first time by the Food and Drug Administration for the treatment of CSA. This system, remede System (Zoll Medical, Inc.), is implanted during a minimally invasive outpatient procedure and has shown a favorable safety and efficacy profile. Currently, patient access to this therapy remains limited by the small number of specialized centers in the United States and the absence of a standard coverage process by insurers. Although a period of evaluation by insurers is expected for new therapies in their early stages, the impact on patients is particularly severe given the already limited treatment options for CSA. Implantation and management of this novel therapy require the establishment of a specialized multidisciplinary program as part of a sleep medicine practice and support from health care systems and hospitals. Several centers in the United States have been successful in building sustainable TPNS programs offering this novel therapy to their patients by navigating the current reimbursement environment. In this article, we review the background and efficacy data of TPNS and briefly address relevant aspects of the clinical activities involved in a TPNS program. The article presents the status of coverage and reimbursement for this novel therapy. We also discuss the current approach to obtaining reimbursement from third-party payors during this transitional period of evaluation by Medicare and other insurers.

An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome is a rare genetic disorder affecting ventilatory response to hypercapnia and/or hypoxemia. We describe a case of diaphragm pacing (DP) failure in a 38-year-old woman with congenital central hypoventilation syndrome who used DP as ventilatory support only during sleep for 24 years. Diagnostic evaluation began with examination of external DP equipment, but adjustment did not elicit adequate diaphragm contractions. Clinical evaluation and transtelephonic monitoring showed absent function of the right pacer and diminished function of the left pacer. The patient had surgical exploration of her internal DP components. The operation revealed that the right pacer receiver had significant circumferential calcium accumulation. After replacement of the receivers in subcutaneous pockets closer to the skin surface, robust diaphragm contractions bilaterally occurred with stimulation. This case suggests DP failure can result from development of calcification and increased distance from the skin surface to the receivers due to weight gain. CITATION: Kwon A, Lodge M, McComb JG, et al. An unusual cause of diaphragm pacer failure in congenital central hypoventilation syndrome. J Clin Sleep Med. 2022;18(3):949-952.

Transvenous phrenic nerve stimulation improves central sleep apnea, sleep quality, and quality of life regardless of prior positive airway pressure treatment.

STUDY OBJECTIVE: Positive airway pressure (PAP) therapy for central sleep apnea (CSA) is often poorly tolerated, ineffective, or contraindicated. Transvenous phrenic nerve stimulation (TPNS) offers an alternative, although its impact on previously PAP-treated patients with CSA has not been examined. METHODS: TPNS responses among PAP-naïve and prior PAP-treated patients from the remede® System Pivotal Trial were assessed. Of 151, 56 (37%) used PAP therapy before enrolling in the trial. Patients were implanted with a TPNS device and randomized to either active or deferred (control) therapy for 6 months before therapy activation. Apnea-hypopnea index (AHI) and patient-reported outcomes (PRO) were assessed at baseline, and 6 and 12 months following active therapy. RESULTS: Patients had moderate-severe CSA at baseline, which was of greater severity and more symptomatic in the PAP-treated vs. PAP-naïve group (median AHI 52/h vs. 38, central apnea index (CAI) 32/h vs. 18, Epworth Sleepiness Scale 13 vs. 10, fatigue severity scale 5.2 vs. 4.5). Twelve months of TPNS decreased AHI to <20/h and CAI to ≤2/h. Both groups showed reductions in daytime sleepiness and fatigue, improved well-being by patient global assessment, and high therapeutic acceptance with 98% and 94% of PAP-treated and PAP-naïve patients indicating they would undergo the implant again. Stimulation produced discomfort in approximately one-third of patients, yet <5% of prior PAP-treated participants discontinued therapy. CONCLUSION: Polysomnographic and clinical responses to TPNS were comparable in PAP-naïve and prior PAP-treated CSA patients. TPNS is a viable therapy across a broad spectrum of CSA patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT01816776; March 22, 2013.

Improving Nocturnal Hypoxemic Burden with Transvenous Phrenic Nerve Stimulation for the Treatment of Central Sleep Apnea.

Nocturnal hypoxemic burden is established as a robust prognostic metric of sleep-disordered breathing (SDB) to predict mortality and treating hypoxemic burden may improve prognosis. The aim of this study was to evaluate improvements in nocturnal hypoxemic burden using transvenous phrenic nerve stimulation (TPNS) to treat patients with central sleep apnea (CSA). The remede System Pivotal Trial population was examined for nocturnal hypoxemic burden. The minutes of sleep with oxygen saturation < 90% significantly improved in Treatment compared with control (p < .001), with the median improving from 33 min at baseline to 14 min at 6 months. Statistically significant improvements were also observed for average oxygen saturation and lowest oxygen saturation. Hypoxemic burden has been demonstrated to be more predictive for mortality than apnea-hypopnea index (AHI) and should be considered a key metric for therapies used to treat CSA. Transvenous phrenic nerve stimulation is capable of delivering meaningful improvements in nocturnal hypoxemic burden. There is increasing interest in endpoints other than apnea-hypopnea index in sleep-disordered breathing. Nocturnal hypoxemia burden may be more predictive for mortality than apnea-hypopnea index in patients with poor cardiac function. Transvenous phrenic nerve stimulation is capable of improving nocturnal hypoxemic burden. Graphical Abstract.

Images: Polysomnographic artifacts in a child with congenital central hypoventilation syndrome.

NONE: Diaphragm pacing (DP), a modality of ventilatory support in children with congenital central hypoventilation syndrome, generates respiration using the patient's own diaphragm as the respiratory pump. We report a 14-year-old boy with congenital central hypoventilation syndrome who uses DP with an uncapped tracheostomy during sleep. Polysomnography to titrate DP settings identified artifacts occurring in regular intervals coinciding with the onset of inspiration during all sleep stages in several channels including legs, snore, and electrocardiogram. Clinicians interpreting polysomnograms performed during DP should become familiar with the multichannel artifacts due to DP impulses. We also identified that our patient was hyperventilated on home DP settings that led to adjustment of DP settings during the polysomnogram to achieve optimal oxygenation and ventilation. Our case also highlights the utility of polysomnography to ensure optimal gas exchange during sleep in children with congenital central hypoventilation syndrome using DP.

Transvenous phrenic nerve stimulation to treat idiopathic central sleep apnea.

STUDY OBJECTIVES: Idiopathic central sleep apnea (ICSA) is a rare disorder diagnosed when known causes of central sleep apnea are excluded. No established treatments exist for ICSA, and long-term studies are lacking. We assessed the long-term effectiveness and safety of transvenous phrenic nerve stimulation in patients with ICSA. METHODS: In the remede System Pivotal Trial, 16/151 (11%) participants with central sleep apnea were diagnosed as having ICSA. Patients were implanted and followed through 18 months of active therapy. Polysomnograms obtained at baseline and at 6, 12, and 18 months were scored by a central laboratory. Sleep metrics and patient-reported quality of life outcomes were assessed. RESULTS: Patients experienced moderate-severe central sleep apnea. The baseline AHI, central apnea index, and arousal index were 40, 25, and 32 events/h of sleep, respectively. These metrics improved at 6, 12, and 18 months of therapy: the AHI decreased by 25, 25, and 23 events/h (P < .001 at each visit), the central apnea index by 22, 23, and 22 events/h (P < .001 at each visit), and the arousal index by 12 (P = .005), 11 (P = .035), and 13 events/h (P < .001). Quality of life instruments showed clinically meaningful improvements in daytime somnolence, fatigue, general and mental health, and social functioning. The only related serious adverse event was lead component failure in 1 patient. CONCLUSIONS: This is the longest prospective study for the treatment of ICSA. Transvenous phrenic nerve stimulation significantly decreased sleep-disordered breathing metrics with consequent improvement in quality of life at 6 months, and all benefits were sustained through 18 months. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Respicardia, Inc. Pivotal Trial of the remede System; URL: https://clinicaltrials.gov/ct2/show/NCT01816776; Identifier: NCT01816776.

First interventional exchange of a left transvenous phrenic nerve stimulation lead from the novel remede system.

The remede system is a novel fully implantable transvenous phrenic nerve stimulation (TPNS) device developed to treat central sleep apnea. No information is published on how to explant or replace its leads. An eighty-one year-old had a fractured lead and we removed it over a wire. However, unbreachable resistances occurred with a new lead deployed over the enclosed wire and interventional endovascular techniques were performed to reimplant a new fully functioning system. This first report demonstrates TPNS lead exchange is possible but can be challenging. Interventional maneuvers and techniques, including balloon angioplasty, can facilitate this procedure.

Central Sleep Apnea in Patients with Heart Failure-How to Screen, How to Treat.

PURPOSE OF REVIEW: Central sleep apnea occurs in up to 50% of heart failure patients and worsens outcomes. Established therapies are limited by minimal supporting evidence, poor patient adherence, and potentially adverse cardiovascular effects. However, transvenous phrenic nerve stimulation, by contracting the diaphragm, restores normal breathing throughout sleep and has been shown to be safe and effective. This review discusses the mechanisms, screening, diagnosis, and therapeutic approaches to CSA in patients with HF. RECENT FINDINGS: In a prospective, multicenter randomized Pivotal Trial (NCT01816776) of transvenous phrenic nerve stimulation with the remede System, significantly more treated patients had a ≥ 50% reduction in apnea-hypopnea index compared with controls, with a 41 percentage point difference between group difference at 6 months (p < 0.0001). All hierarchically tested sleep, quality of life, and daytime sleepiness endpoints were significantly improved in treated patients. Freedom from serious related adverse events at 12 months was 91%. Benefits are sustained to 36 months. Transvenous phrenic nerve stimulation improves quality of life in patients with heart failure and central sleep apnea. Controlled trials evaluating the impact of this therapy on mortality/heart failure hospitalizations and "real world" experience are needed to confirm safety and effectiveness.

Transvenous phrenic nerve stimulation for central sleep apnea is safe and effective in patients with concomitant cardiac devices.

BACKGROUND: Central sleep apnea is common in heart failure patients. Transvenous phrenic nerve stimulation (TPNS) requires placing a lead to stimulate the phrenic nerve and activate the diaphragm. Data are lacking concerning the safety and efficacy of TPNS in patients with concomitant cardiovascular implantable electronic devices (CIEDs). OBJECTIVE: To report the safety and efficacy of TPNS in patients with concomitant CIEDs. METHODS: In the remede System Pivotal Trial, 151 patients underwent TPNS device implant. This analysis compared patients with concomitant CIEDs to those without with respect to safety, implant metrics, and efficacy of TPNS. Safety was assessed using incidence of adverse events and device-device interactions. A detailed interaction protocol was followed. Implant metrics included overall TPNS implantation success. Efficacy endpoints included changes in the apnea-hypopnea index (AHI) and quality of life. RESULTS: Of 151 patients, 64 (42%) had a concomitant CIED. There were no significant differences between the groups with respect to safety. There were 4 CIED oversensing events in 3 patients leading to 1 inappropriate defibrillator shock and delivery of antitachycardia pacing. There was no difference in efficacy between the CIED and non-CIED subgroups receiving TPNS, with both having similar percentages of patients who achieved ≥50% reduction in AHI and quality-of-life improvement. CONCLUSION: Concomitant CIED and TPNS therapy is safe. The presence of a concomitant CIED did not seem to impact implant metrics, implantation success, and TPNS efficacy. A detailed interaction protocol should be followed to minimize the incidence of device-device interaction.

Meta-analysis of Usefulness of Phrenic Nerve Stimulation in Central Sleep Apnea.

Transvenous neurostimulation of the phrenic nerve (PNS) is a potentially improved and unique approach to the treatment of central sleep apnea (CSA). There have been multiple studies with limited individuals evaluating the efficacy of PNS. Our aim was to review and pool those studies to better understand whether phrenic nerve stimulation is efficacious in the treatment of CSA. The initial search on Pubmed retrieved a total of 97 articles and after screening all articles, only 5 could be included in our quantitative analysis. Pooling of data from 5 studies with a total of 204 patients demonstrated a reduction of mean apnea hypopnea index with PNS compared to controls by -26.7 events/hour with 95% confidence interval and P value of [CI (-31.99, -21.46), I2 85, p 0.00]. The mean difference in central apnea index was -22.47 [CI (-25.19, -19.76), I2 0, p 0.00]. The mean reduction in the oxygen desaturation index of 4% or more demonstrated a decrease in PNS group by -24.16 events/hour [(CI -26.20, -22.12), I2 0, p 0.00] compared with controls. PNS resulted in mean reduction in arousal index of -13.77 [CI (-16.15, -11.40), I2 0, p 0.00]. The mean change in percent of time spent in rapid eye movement sleep demonstrated a nonsignificant increase in PNS group by 1.01 % [CI (-5.67, 7.86), I293, p 0.75]. In conclusion, PNS therapy for treating CSA demonstrated positive outcomes but larger randomized studies are needed to evaluate the safety and clinical outcomes.

Novel phrenic nerve stimulator treats Cheyne-Stokes respiration: polysomnographic insights.

None: A symptomatic patient with atrial fibrillation and Cheyne-Stokes respiration (CSR) was implanted with a transvenous phrenic nerve stimulation (TPNS) device-the remede System-that is indicated for adult patients with moderate to severe central sleep apnea. Sleep recordings demonstrated that TPNS eliminated periodic breathing by activating the diaphragm and stabilizing respiratory patterns. These recordings of preprogrammed periods on versus off TPNS illustrate prompt (1) stabilization of tidal airflow, respiratory effort, and oxygenation as stimulation amplitude increased stepwise and (2) recurrence of CSR immediately after TPNS deactivated. Despite differences in respiratory patterns, minute ventilation was comparable during periods on and off TPNS. These findings suggest that diaphragmatic pacing entrains ventilation without disrupting sleep, accounting for observed improvements in periodic breathing, gas exchange, sleep architecture, and quality of life. Effective means to relieve CSR could potentially mitigate nocturnal cardiovascular stress and disease progression.

Positional impairment of gas exchange during diaphragm pacing alleviated by increasing amplitude settings in congenital central hypoventilation syndrome.

None: Diaphragm pacing (DP) by phrenic nerve stimulation is a modality of chronic ventilatory support in individuals with congenital central hypoventilation syndrome (CCHS). We report a 9-year-old girl with CCHS who uses DP without tracheostomy during sleep. Her parents report hypoxemia and hypercapnia related to positional changes of the body during sleep requiring frequent adjustment of pacer settings. Overnight polysomnography was performed to titrate DP settings that showed adequate gas exchange in the supine position, but intermittent hypoxemia and hypercapnia were noted in the left decubitus position without obstructive sleep apnea occurring. Subsequently, the DP amplitude settings were increased during polysomnography, thereby identifying and treating positional hypoxemia and hypercapnia in various body positions. Our case emphasizes the importance of polysomnography in children with CCHS using DP to monitor for sleep-disordered breathing and titration of DP settings to achieve optimal oxygenation and ventilation with different body positions during sleep.

Interventional techniques to increase implantation success of transvenous phrenic nerve stimulation for central sleep apnea treatment.

PURPOSE: Central sleep apnea (CSA) is a highly common comorbidity in heart failure (HF) patients and is known to deteriorate quality of life and prognosis. Effective treatment options are scarce. Transvenous phrenic nerve stimulation (PNS) has been shown to be effective and safe in CSA treatment in HF. However, lead implantation may be difficult or fail due to anatomical or technical challenges. We report novel and innovative approaches applying different interventional techniques to enhance PNS implantation success, allowing otherwise missing CSA treatment. METHODS: Twenty-seven consecutive HF patients (86% male, mean age: 69 ± 11 years; reduced left ventricular ejection fraction in 16 patients (57%)) were included in this study who were unable to tolerate or had contraindications for mask-based therapy. We evaluated PNS total implantation success, procedural characteristics, and feasibility and success rates of intravascular interventions to facilitate PNS lead implantation in otherwise ineffective procedures. RESULTS: Seven lead implantation attempts (24%) required additional intravascular interventional action to facilitate successful implantation, mainly consisting of balloon angioplasties to allow optimal PNS lead placement. Two procedures remained unsuccessful and two patients underwent a second procedure due to stimulation side effects and lead fracture respectively. All over, no complications resulted from application of interventional techniques to achieve a 93% implantation success rate. CONCLUSION: Transvenous PNS lead placement for CSA treatment can be difficult and challenging. However, interventional intravascular techniques markedly increase implantation success and thereby allow application of this therapy for effective CSA treatment in most patients without additional complications.