Elevated Central and Mixed Apnea Index after Upper Airway Stimulation.

OBJECTIVE: Upper airway stimulation (UAS) is used to treat patients with moderate to severe obstructive sleep apnea (OSA). The aim of this study is to report the incidence and potential predictors of elevated central and mixed apnea index (CMAI) after UAS. STUDY DESIGN: Retrospective chart review of patients undergoing UAS. SETTING: Tertiary care center. SUBJECTS AND METHODS: Included patients underwent UAS for OSA at our institution between 2014 and 2018. Data collected included demographic information, implantation records, and pre- and postoperative polysomnography (PSG) results. CMAI ≥5 was considered elevated. Post hoc univariate analysis was performed to evaluate factors associated with elevated CMAI. RESULTS: In total, 141 patients underwent UAS at our institution. This included 94 men and 47 women with a mean age of 61.2 ± 11.0 years and a mean body mass index of 29.1 ± 3.9 kg/m2. Five patients had an elevated CMAI after surgery during UAS titration. Demographics, comorbid conditions, and device settings were not associated with an elevated postoperative CMAI (P > .05). CONCLUSION: The occurrence of an elevated CMAI after surgery may represent treatment-emergent events. Demographics, comorbid conditions, and UAS device settings were not associated with central and mixed apneic events. LEVEL OF EVIDENCE: 4.

Effect of Gender, Age, and Profound Disease on Upper Airway Stimulation Outcomes.

OBJECTIVE: To evaluate treatment outcomes of upper airway stimulation (UAS) in obstructive sleep apnea (OSA) patients based on patient age, gender, and preoperative disease severity. METHODS: Retrospective chart review of patients undergoing UAS from 2014 to 2018 at a tertiary care center. Data collected included demographic information, implantation records, and pre- and postoperative polysomnography (PSG) results. Profound OSA was defined as AHI >65 and age ≥65 was considered advanced age. The primary outcome measured was initial treatment response, defined as a post-operative AHI <20 with a >50% reduction from baseline. RESULTS: 145 patients underwent UAS at our institution including 98 males and 47 females with a mean age of 61.7 ± 11.5 years, mean BMI of 29.1 ± 3.9 kg/m2, and mean preoperative AHI of 34.1 ± 18.2 events/hour. After surgery, patients had a significantly lower mean AHI of 8.6 ± 15.0 events/hour (<0.001). Older patients had a lower initial treatment response rate (78%) when compared to their younger counterparts (94%) (P = 0.005). Male gender and profound disease status did not significantly impact treatment response rates; young age was the only variable found to predict early treatment response on multivariate analysis (P = 0.003). CONCLUSION: Although the overall OSA population showed significant postoperative AHI reduction with UAS, patients age ≥65 years were less likely to have an initial response to treatment, when compared to their younger counterparts. A larger proportion of elderly patients and patients with profound OSA had residual moderate disease (AHI > 15) after UAS. LEVEL OF EVIDENCE: 4.