The Effect of Surgical Therapy for Obstructive Sleep Apnea on Blood Pressure and Peripheral Arterial Tonometry

OBJECTIVE

To determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA).

STUDY DESIGN

A prospective, self-controlled study from 2018 to 2023.

SETTING

Two academic medical centers.

METHODS

Seventy-four patients underwent surgery for OSA, including: tonsillectomy, adenoidectomy, epiglottidectomy, modified uvulopalatopharyngoplasty, maxillary expansion, and maxillomandibular advancement. Twenty-four-hour ambulatory blood pressure (BP), peripheral arterial tonometry (PAT)-based home sleep study, and sleep-related patient-reported outcomes (PROs) were captured preoperatively and at 6 months postoperatively. Paired T-tests evaluated changes in outcomes after surgery.

RESULTS

Forty-one patients successfully completed preoperative and postoperative assessments. Patients were generally middle-aged (43.8 ± 12.5 years), obese (BMI 33.0 ± 5.8 kg/m2), male (68%), White (71%), and had severe OSA (apnea-hypopnea index [AHI] 33.9 ± 29.5 events/h). The 4% oxygen desaturation index (ODI) decreased from 30.7 ± 27.1 to 12.2 ± 13.6 events/h (P < .01) after surgery. There was no significant difference in 24-h BP following surgery, though clinically meaningful reductions in nocturnal systolic (-1.95 [-5.34, 1.45] mmHg) and nocturnal diastolic (-2.30 [-5.11, 0.52] mmHg) blood pressure were observed. Stratified analysis showed patients undergoing skeletal surgery (n = 17) demonstrated larger average reductions compared to those undergoing soft tissue surgery in nocturnal systolic (-4.12 [-7.72, -0.51] vs -0.10 [-5.78, 5.58] mmHg) and nocturnal diastolic (-3.94 [-7.90, 0.01] vs -0.90 [-5.11, 3.31] mmHg) pressures. No meaningful changes were observed in PAT Autonomic Index (PAI) measurements.

CONCLUSION

Surgical therapy for OSA did not demonstrate statistically significant improvements in 24-h BP. However, clinically meaningful reductions in nocturnal BP were observed, particularly in skeletal surgery patients, supporting the need for larger studies of cardiovascular outcomes following OSA surgery.

Hypoglossal Nerve Stimulation and Cardiovascular Outcomes for Patients With Obstructive Sleep Apnea: A Randomized Clinical Trial

Importance

Sham-controlled trials are needed to characterize the effect of hypoglossal nerve stimulation (HGNS) therapy on cardiovascular end points in patients with moderate-severe obstructive sleep apnea (OSA).

Objective

To determine the effect of therapeutic levels of HGNS, compared to sham levels, on blood pressure, sympathetic activity, and vascular function.

Design, Setting, and Participants

This double-blind, sham-controlled, randomized crossover therapy trial was conducted from 2018 to 2022 at 3 separate academic medical centers. Adult patients with OSA who already had an HGNS device implanted and were adherent and clinically optimized to HGNS therapy were included. Participants who had fallen asleep while driving within 1 year prior to HGNS implantation were excluded from the trial. Data analysis was performed from January to September 2022.

Interventions

Participants underwent a 4-week period of active HGNS therapy and a 4-week period of sham HGNS therapy in a randomized order. Each 4-week period concluded with collection of 24-hour ambulatory blood pressure monitoring (ABPM), pre-ejection period (PEP), and flow-mediated dilation (FMD) values.

Main Outcomes and Measures

The change in mean 24-hour systolic blood pressure was the primary outcome, with other ABPM end points exploratory, and PEP and FMD were cosecondary end points.

Results

Participants (n = 60) were older (mean [SD] age, 67.3 [9.9] years), overweight (mean [SD] body mass index, calculated as weight in kilograms divided by height in meters squared, 28.7 [4.6]), predominantly male (38 [63%]), and had severe OSA at baseline (mean [SD] apnea-hypopnea index, 33.1 [14.9] events/h). There were no differences observed between active and sham therapy in 24-hour systolic blood pressure (mean change on active therapy, -0.18 [95% CI, -2.21 to 1.84] mm Hg), PEP (mean change on active therapy, 0.11 [95% CI, -5.43 to 5.66] milliseconds), or FMD (mean change on active therapy, -0.17% [95% CI, -1.88% to 1.54%]). Larger differences between active and sham therapy were observed in a per-protocol analysis set (n = 20) defined as experiencing at least a 50% reduction in apnea-hypopnea index between sham and active treatment.

Conclusions and Relevance

In this sham-controlled HGNS randomized clinical trial, mean 24-hour systolic blood pressure and other cardiovascular measures were not significantly different between sham and active HGNS therapy. Several methodologic lessons can be gleaned to inform future HGNS randomized clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT03359096.

0785 Cardiovascular Outcomes For Obstructive Sleep Apnea With HGNS Therapy

Introduction

Obstructive sleep apnea (OSA) is linked to cardiovascular disease, particularly when left untreated. Hypoglossal nerve stimulation (HGNS) is a novel and promising PAP alternative as it is well-tolerated and reduces OSA severity; however, its effect on mitigating cardiovascular risk secondary to OSA is unknown. The aim of this study is to evaluate the effect of HGNS on sympathetic and vascular function. Our hypothesis is mean 24-hour systolic blood pressures (SBP) will be improved at “active” levels of HGNS.

Methods

This study is a double-blinded, sham-controlled, randomized controlled therapy crossover trial. Subjects are randomized for four weeks in each arm to either “active” HGNS or “sham” HGNS, with “sham” HGNS being defined as the lowest voltage at which HGNS was sensed by the patient and/or visualized by the principal investigator. Included patients had already been implanted with the Inspire® device. Patients were excluded for active PAP therapy use, recent automobile accidents, a minimum difference (&lt;30%) between “active” and “sham” voltages, and pregnancy.

Results

53 patients met all inclusion criteria. Overall, the study cohort was older (mean [SD] age 66.8 [10.2]), overweight (BMI 28.8 [4.36]), 60% male, and predominantly of white race. There was no significant difference in mean 24-hour SBP between “active” and “sham” HGNS (122.4 mmHg [12.2] vs. 122.4 mmHg [11.2], respectively). Further, there was no significant difference in mean SBP during sleep between “active” and “sham” HGNS (115.0 mmHg [15.2] vs. 115.2 mmHg [14.4], respectively).

Conclusion

This is a randomized controlled trial evaluating cardiovascular outcomes in patients with OSA using HGNS therapy. The HGNS system permits a unique investigation of the therapy “on/off” effect on measures of the sympathetic nervous system and vascular health. “Active” HGNS levels, compared to “sham” HGNS levels, do not appear to reduce mean systolic blood pressure during wake or sleep periods.

Support (If Any)

Raj C. Dedhia, MD, MSCR is supported by the American Heart Association and the American Sleep Medicine Foundation.

The role of craniofacial maldevelopment in the modern OSA epidemic: a scoping review

STUDY OBJECTIVES

There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea.

METHODS

A comprehensive literature search was performed using the Ovid Medline database from inception to May, 2020 with relevance to craniofacial development in 5 clinically-oriented variables: diet, secular change, breastfeeding/non-nutritive sucking habits (NNSH), nasal obstruction/mouth breathing, and masticatory muscle function. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE) was used to assess studies based on study design.

RESULTS

18,196 articles were initially identified, of which 260 studies were fully reviewed and 97 articles excluded. The remaining 163 articles were categorized as follows: Secular change (n = 16), Diet (n = 33), Breastfeeding/NNSH (n = 28), Nasal obstruction/Mouth breathing (n = 57), and Masticatory muscle function (n = 35). 93% of included studies reported a significant association between craniofacial morphology and environmental factors. The majority of studies were characterized as low LoE studies with 90% of studies being LoE 4 or 5.

CONCLUSIONS

The studies in this review suggest that environmental factors are associated with changes in craniofacial development. However, most studies were heterogeneous and low-level studies, making strong conclusions about these relationships difficult. Future rigorous studies are needed to further our understanding of environmental influences on craniofacial development and OSA risk.

Influence of apnea vs hypopnea predominance in predicting mean therapeutic positive airway pressures among patients with obstructive sleep apnea

STUDY OBJECTIVES

Lower therapeutic positive airway pressure (PAP) levels are associated with improved response to non-PAP therapies in the treatment of obstructive sleep apnea. The aim of this study was to evaluate the prevailing notion that patients with apnea-predominant obstructive sleep apnea require higher therapeutic PAP levels compared to patients with hypopnea-predominant obstructive sleep apnea.

METHODS

An institutional review board-approved retrospective review was performed using strict inclusion criteria: presence of type I or III sleep study, apnea-hypopnea index > 10 events/h, and adherence to auto-adjusting continuous positive airway pressure. Patients were stratified by apnea (> 50% apneas) or hypopnea (≤ 50% apneas) predominance, and PAP data were compared. Statistical analyses were performed using Student's t test and linear regression modeling.

RESULTS

Between January 1, 2018 and January 1, 2020, 500 patients met inclusion criteria. Two hundred twenty-one (44.1%) patients were apnea-predominant and 279 (55.8%) were hypopnea-predominant. Apnea-predominant patients had a slightly greater mean PAP (9.01 vs 8.36, P = .002) than hypopnea-predominant patients. Univariable and multivariable linear regression of 7 variables (obstructive apnea percentage, age, sex, body mass index, apnea-hypopnea index, O₂ nadir, mask type) showed obstructive apnea percentage was the weakest predictor of therapeutic PAP levels.

CONCLUSIONS

Apnea-predominant individuals demonstrated a clinically insignificant difference in PAP level compared to hypopnea-predominant individuals; moreover, obstructive apnea percentage was not a strong predictor of therapeutic PAP levels. Of the modeled variables, the strongest predictor of PAP level was apnea-hypopnea index. Further studies are needed to explore these relationships as well as additional variables that may contribute to predicting therapeutic PAP levels.

CITATION

Yu JL, Liu Y, Tangutur A, et al. Influence of apnea vs hypopnea predominance in predicting mean therapeutic positive airway pressures among patients with obstructive sleep apnea. J Clin Sleep Med. 2021;17(11):2171-2178.