Upper Airway Pacing for Obstructive Sleep Apnea Charles W. Atwood, Jr., MD, FCCP, FAASM Assoc Professor of Medicine University of Pittsburgh Sleep Program

Upper Airway Pacing for Obstructive Sleep Apnea Charles W. Atwood, Jr., MD, FCCP, FAASM Assoc Professor of Medicine University of Pittsburgh Sleep Program Director, VA Pittsburgh Healthcare System

Disclosure: Charles W. Atwood, Jr., MD Research Support Federal NIH, NIDDK - OSA Dept of Defense Lung cancer Industry Research Grant Philips-Respironics, Inc. Forest Research Institute Industry advisory -Philips-Respironics -Carecore National

Outline Background Upper Airway Stimulation STAR Trial Conclusions

Pathogenesis of Obstructive Sleep Apnea AJRCCM 2005 172:13631370 Promotion of Airway Collapse Promotion of Airway Patency Negative pressure on inspiration Extralumenal positive Pressure Fat Deposition Small mandible Pharyngeal dilator Muscle contraction (genioglossus) Lung volume (longitudinal traction) Risk Mediated by a: Gene (Obesity, Craniofacial Structure, Respiratory Control / Environment (Obesity) Interaction

Sleep 2008 31:1071-78 Sleep Disordered Breathing and Mortality: Eighteen-Year Follow-up of the Wisconsin Sleep Cohort (n = 1396) SDB, irrespective of EDS, was associated with increased mortality. The striking high CV mortality risk in untreated severe SDB, suggests that SDB Rx should not be contingent on daytime sleepiness symptoms

Increased Prevalence of Sleep-Disordered Breathing in Adults The current prevalence estimates of moderate to severe sleep-disordered breathing (apnea-hypopnea index, measured as events/hour, 15) are: 10% (95% CI: 7, 12) among 3049-year-old men 17% (95% CI: 15, 21) among 5070-year-old men 3% (95% CI: 2, 4) among 3049-year-old women 9% (95% CI: 7, 11) among 5070 year-old women These estimated prevalence rates represent substantial increases over the last 2 decades - relative increases of between 14% and 55% depending on the subgroup Am J Epidemiol. 2013;177(9):10061014

OSA and Cardiovascular Disease Primary HTN: 35% prevalence Drug-resistant HTN: 65 to 80% prevalence Most common secondary cause Coronary Artery Disease: 30% prevalence Heart failure: 21-37% prevalence Atrial Fibrillation: OSA present 5 X more likely Stroke: 60% prevalence Circulation 2012;126:1495-1510

Cumulative Incidence of Fatal CV Events Cumulative Incidence of Non-fatal CV Events AIM: Observational study to compare incidence of fatal and non-fatal cardiovascular events in simple snorers, patients with untreated OSA, patients treated with CPAP, and healthy men recruited from the general population. Design: Prospective observational cohort. 264 healthy men, 377 simple snorers, 403 with untreated mild-moderate OSA (AHI 5-30), 235 with untreated severe OSA (AHI > 30), and 372 with OSA and treated with CPAP Lancet 2005 365: 104653 Months. Conclusion: In men, severe OSA significantly increases the risk of fatal and non-fatal cardiovascular events. CPAP treatment reduces this risk. Long-term cardiovascular outcomes in men with OSA

CPAP Therapy and Adherence PAP therapy when used consistently results in decreased daytime sleepiness*, improved HRQOL, and decreased vascular risk. Recent studies of CPAP therapy investigated adherence: APPLES Study largest RCT in sleep medicine to date (1,516 subjects enrolled) and CPAP adherence rate was 39% at 6-months use of CPAP therapy (174 of 443) Home PAP Study Evaluation of standard OSA care vs. home-base diagnostics and titration. Results of 3-month follow-up: CPAP adherence was 39% (Lab titration); CPAP adherence was 50% (Home titration) Conclusion: CPAP is first-line therapy and effective when consistently used by OSA patients. Alternative therapy options for moderate or severe OSA patients who are nonadherent to PAP are desirable

OSA Value of Selected Treatment Options SnoringMild Sleep Apnea Moderate or Severe Sleep Apnea Weight loss Nasal decongestant Positional therapy Surgery (adults) Surgery (children) Oral appliance PAP Darker more valuable. Upper Airway Stimulation therapy treatment indication Only Positive Airway Pressure (PAP) and Surgery indicated for patients with Moderate or Severe OSA http://www.sleepapnea.org/diagnosis-and- treatment/treatment-options.html

The Inspire System: Built on a proven, commercial grade technology platform Stimulation Lead - Self sizing cuff - Multiple stimulation vectors Implanted Pulse Generator (IPG) - 6-8 year projected longevity Effort Sensor - Secure, stable location - Direct measurement of ventilatory effort - Short surgical tunnel

Upper Airway Anatomy & Stimulation Site Stimulation Site: Medial branch of the hypoglossal nerve, activates only protrusors (genioglossus, geniohyoid), distal to retractors (styloglossus and hyoglossus) Styloglossus (SG) Hypoglossal Nerve (XII) Hyoglossus (HG) Superior root of ansa cervicalis Genioglossus (GG) Geniohyoid (GH) Thyrohyoid Stimulation Site Superior Longitudinal Inferior Longitudinal

No airway anatomy alteration Works with patients physiology Standardized implant technique Fast post op recovery Patient Programmer Turn therapy ON/OFF Adjust amplitude Device Programmer Adjust Therapy Parameters Bluetooth enables remote adjustments during titration studies in the sleep lab Upper Airway Stimulation

Basic Therapy Parameters Stimulating Pulses Amplitude (V) primary stimulation strength adjustment Rate (Hz) default 33 Hz Pulse Width (sec) default 90 sec Onset Offset Sensor Signal ExpiratoryInspiratory

Upper Airway Stimulation advances tongue to open airway Airway Obstructed STIMULATION OFF Tongue Advanced STIMULATION ON Tongue base Epiglottis Tongue base advancement with stimulation Tongue base Observed during sleep endoscopy

Effect of stimulation on the Retropalatal and Retrolingual airway area between awake endoscopy and DISE Eur Respir J 2014; in press

Increases in retropalatal and retrolingual area comparing no stimulation with progressively higher levels of stimulation during DISE No stimulation First sensationBulk movementTitrated therapeutic Sub-discomfort Retropalatal Retrolingual Eur Respir J 2014; in press

PSG: Effect of Stimulation Therapy ONTherapy OFF 30 seconds EEG EMG Nasal Pressure Thermo Chest Abdomen SpO2

In-lab PSG Titration Algorithm Increase amplitude by 0.1 to 0.2 volts if 5 obstructive apneas or hypopneas or loud, unambiguous snoring 10 min Start: 0.2 V below Functional Threshold Reduce amplitude by 0.1 to 0.2 volts if stimulation causes persistent arousals or is poorly tolerated Amplitude (volts) Time (minutes) Therapeutic Amplitude Range 30 minutes in the patients preferred sleep position with minimum occurrence of events, preferably with REM sleep observed Arousal Threshold 20 *Adapted from current practice guidelines established for CPAP titration by the American Academy of Sleep Medicine, ref: Journal of Clinical Sleep Medicine, Vol. 4, No 2, 2008

Clinical Trial Experience Proof of Principle Trial 8 patients 4 Centers Completed in 2001 Demonstrated therapy concept Feasibility Trial 34 patients 8 Centers Completed in 2010 Demonstrated safety and patient selection References: 1.Operative technique in otolaryngology-head and neck surgery. 2012 23(3): 227-33 2.Journal of Clinical Sleep Medicine 2013 9 (5) 433-438 3.The Laryngoscope 2012 122(7): 1626- 33 Reference: Arch Otolaryngol Head Neck Surg 2001 127:1216-1223

Examples collapse at the level of the palate during DISE Anteroposterior collapse Concentric collapse JCSM 2013 9 (5) 433-438

Inspire UAS effect during DISE Palate Therapy OFF Palate Therapy ON Posterior oropharyngeal wall Posterior Uvula LR P Epiglottis Lingual Tonsils LR P L R P L R P Reference: 2 slices Palate Tongue-Base Tongue B ase Therapy OFF Tongue Base Therapy ON

Stimulation Therapy for Apnea Reduction (STAR Trial) ClinicalTrials.gov NCT01161420 Hypothesis: Unilateral Stimulation of the Hypoglossal Nerve during sleep will safely and effectively treat Obstructive Sleep Apnea NEJM 2014 370:139-49

Outcome Measures: Baseline vs. 12-Months Co-Primary Apnea Hypopnea Index Oxygen desaturation index (ODI 4% ) Secondary Epworth Sleepiness Scale Functional Outcomes of Sleep Questionnaire SaO2 < 90% NEJM 2014 370:139-49

Methods I Prospective, multicenter trial with randomized therapy withdrawal arm in participants with moderate to severe OSA who had failed or had not tolerated CPAP. All underwent a screening polysomnographic (PSG) study, surgical consultation, and drug- induced sedation endoscopy (DISE). Participants without complete concentric collapse at the retropalatal airway received an implanted neurostimulator NEJM 2014 370:139-49

Inclusion Criteria AHI between 20 and 50 Have failed or have not tolerated CPAP Central and mixed sleep apnea accounted for < 25% of all AHI events Absence of significant apnea when sleeping in a non-supine position (AHI non-supine > 10) 28 NEJM 2014 370:139-49

Exclusion Criteria BMI > 32 Neuromuscular diseases Severe Co-Morbid Cardiopulmonary Disease Other chronic sleep disorders Complete concentric collapse at the level of soft palate during drug-induced sedation endoscopy (DISE) 29 NEJM 2014 370:139-49

Examples collapse at the level of the palate during DISE Anteroposterior collapse Concentric collapse JCSM 2013 9 (5) 433-438

Methods II Participants were followed for 12 months to assess efficacy and adverse events. PSG (AHI and ODI) Quality of life measures Epworth Sleepiness Scale (ESS) Functional Outcomes of Sleep Questionnaire (FOSQ) Responders after 12 months of continuous therapy were randomized to one week of therapy suspension (OFF) vs. therapy maintenance (ON) and evaluated with PSG. NEJM 2014 370:139-49

Consort Flow Chart NEJM 2014 370:139-49

Baseline Characteristics of the Study Population (N = 126) CharacteristicsMean SD or N (%) Age, year54.5 10.2 Male sex, no. (%)83% Caucasian race, no. (%)97% Body Mass Index, kg/m 2 28.4 2.6 Neck size, cm41.2 3.2 Systolic BP, mmHg128.7 16.1 Diastolic BP, mmHg81.5 9.7 Hypertension, no. (%)38% Diabetes9% Asthma5% Congestive heart failure2% Prior UPPP, no. (%)18% NEJM 2014 370:139-49

Primary Outcome Measures: AHI and ODI (n = 124) 68% reduction in AHI from baseline to Month-12 70% reduction in ODI from baseline to Month-12 AHIODI *Median and error bar in standard error p < 0.0001 NEJM 2014 370:139-49

Secondary Outcome Measures: FOSQ & ESS (n = 123) FOSQ ScoreESS Scale *Median and error bar in standard error p < 0.0001 NEJM 2014 370:139-49

Secondary Outcome Measure: SaO2 < 90% p < 0.05 NEJM 2014 370:139-49

Randomized Controlled Therapy Withdrawal *mean and error bar in standard error p < 0.0001 p = n.s. NEJM 2014 370:139-49

Relevant Adverse Events Serious: Device related 1% Device revision Non Serious: Procedure related ~ 25% Pain (minimal, most did not require narcotics - substantially less than UPPP) Non-Serious: Device related ~ 33% Tongue discomfort / abrasion (time limited) 1% Mild or Mod Infection (cellulitis) * One Death Unrelated to the Trial NEJM 2014 370:139-49

Adherence Data After 12 months follow up of 126 implanted participants, 124 participants (98%) remained active users of UAS therapy. One participant died unexpectedly due to an unrelated cause, and one participant requested a device removal for personal reasons. Based on self reports from 123 participants at 12 months, 86% (106 of 123) used the device daily and 93% (115 of 123) used the device at least 5 days a week. The UAS device registers the cumulative hours of stimulating pulses duration since last device interrogation. At the 12-month visit, the average stimulation pulses time was 2.6 hours per night. The stimulating pulses were not delivered continuously during sleep, and were only delivered during the late expiratory and inspiratory phases of respiration. NEJM 2014 370:139-49

Measurement of Use of Therapy NEJM 2014 370:139-49

Upper Airway Stimulation effect on Sleep Baseline N = 126 12 Month N = 124 Sleep Time, min Mean(SD) % of Total Sleep Mean(SD) % of Total Sleep P value Total Sleep 364.8 (68.0) 333.7 (69.3)

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Upper Airway Pacing for Obstructive Sleep Apnea Charles W. Atwood, Jr., MD, FCCP, FAASM Assoc Professor of Medicine University of Pittsburgh Sleep Program