Lateral pharyngoplasty: polysomnographic results and phenotype-based analysis of OSA.

Abstract

There are several surgical treatments for obstructive sleep apnea (OSA) including lateral pharyngoplasty (LP) haveyielded promising results, clearly improving symptoms of the disease. However, there are few publications inrelation to polysomnographic (PSG) results, and patient selection remains a challenge. There are currently fourpathophysiological phenotypes for OSA: anatomical, low arousal threshold, ventilatory instability, and poor muscleresponse. This study sought to evaluate the PSG results of LP and to verify whether the phenotypic profile ispredictive of surgical success. This was an observational, retrospective, cross-sectional study that analyzed the PSG results (pre-surgical and atleast 6 months after surgery) of patients treated with Cahali's LP. To assess phenotypes, the following variables of interest (obtained from thepre-operative PSG) were used: apnea-hypopnea index (AHI) during REM sleep (AHIrem), percentage ofhypopneas in the AHI, number of central or mixed apneas, and AHIrem and non-REM AHI ratio. Of 46 patients, it was possible to evaluate the phenotype in 28 patients. There were significant differences in the AHI values, ranging from 37.5 (20.8-49.7) to 10.3 (2.3-33.0) (p <0.001). The minimum oxyhemoglobin saturation ranged from 78 ± 11 to 83 ± 8p = 0.008. The time withoxyhemoglobin saturation < 90% ranged from 3.6 min (0.5-9.1) to 0.0 (0.0-1.5) p = 0.031. An AHIrem of <20 events/h showed a positive correlation with surgical success. LP is efficient for the treatment of OSA, yielding significant improvement in all respiratory parameters evaluated byPSG. A pre-operative AHIrem of < 20 events/h was associated withsurgical success. Other variables of interest fordetermining the phenotypes were not predictors of surgical success.