Evaluation of drug-induced sleep endoscopy as a patient selection tool for implanted upper airway stimulation for obstructive sleep apnea

Abstract

Study objectives: To study the possible predictive value of drug-induced sleep endoscopy (DISE) in assessing therapeutic response to implanted upper airway stimulation (UAS) for obstructive sleep apnea (OSA).

Methods: During DISE, artificial sleep is induced by midazolam and/or propofol, and the pharyngeal collapse patterns are visualized using a flexible fiberoptic nasopharyngoscope. The level (palate, oropharynx, tongue base, hypopharynx/epiglottis), the direction (anteroposterior, concentric, lateral), and the degree of collapse (none, partial, or complete) were scored in a standard fashion.

Results: We report on the correlation between DISE results and therapy response in 21 OSA patients (apnea-hypopnea index [AHI] 38.5 ± 11.8/h; body mass index [BMI] 28 ± 2 kg/m(2), age 55 ± 11 y, 20 male/1 female) who underwent DISE before implantation of a UAS system. Statistical analysis revealed a significantly better outcome with UAS in patients (n = 16) without palatal complete concentric collapse (CCC), reducing AHI from 37.6 ± 11.4/h at baseline to 11.1 ± 12.0/h with UAS (p < 0.001). No statistical difference was noted in AHI or BMI at baseline between the patients with and without palatal CCC. In addition, no predictive value was found for the other DISE collapse patterns documented.

Conclusions: The absence of palatal CCC during DISE may predict therapeutic success with implanted UAS therapy. DISE can be recommended as a patient selection tool for implanted UAS to treat OSA.

Keywords: Electrical stimulation; hypoglossal nerve; neuromodulation; obstructive sleep apnea hypopnea syndrome; prediction; sleep disordered breathing; snoring.

Figure 1. Venn diagram showing the percentages per upper airway level including the percentages of overlap between the different levels in case of multi-level collapse

Figure 2. Example of anteroposterior (left) versus concentric (right) collapse at the level of the palate during DISE

Figure 3. Apnea-hypopnea index (AHI) in patients with (black color) and without (white color) complete concentric collapse (CCC) at the level of the palate 6 months after UAS implantation during stimulation as compared to baseline without UAS; the different grayscales represent the distinction between normal nocturnal breathing (AHI < 5/h sleep), mild OSA (AHI 5-15/h), moderate OSA (AHI 15-30/h), and severe OSA (AHI > 30/h)

Left panel: boxplots showing the 75th and 25th percentiles by the upper and lower margins, the mean values by the closed circle, and the median values by the horizontal line. Whiskers represent the maximum value (top) and the minimum value (bottom) of the dataset; this range includes all data except the outliers. Outliers are represented by an open circle. Right panel: the individual patient response data are plotted in line graphs, with the white squares being the AHI values in patients without CCC and the black circles being the AHI values in patients with CCC. N.S., not significant; ***p < 0.001.