Sleep parameter characteristics of patients with OSA who have retropalatal circumferential narrowing and the clinical significance of lateral pharyngeal wall collapse during sleep

Comparison of clinical characteristics in RC narrowing vs. AP collapse

Clinical characteristics of patients with RC narrowing and those with only AP narrowing were compared. DISE findings show that 44% of patients (N = 47) exhibited AP narrowing, and 48% (n = 51) had circumferential narrowing at the level of the soft palate. LPW collapse without AP narrowing was observed in just 8 patients. Twenty-six patients with RC narrowing had grade 2 narrowing, while 25 patients had grade 3 narrowing (Fig. 1). The mean age of the patients with RC narrowing was 48.2 years (range, 20–54 years), and 94% were male. Their mean body weight was 82.2 kg, average height was 171 cm, and their mean body mass index (BMI) was 28.2 kg/m2. No difference was found in the mean age, height, or sex ratio among patients with RC narrowing and those with AP narrowing. However, both mean body weight and BMI of patients with RC narrowing were significantly higher than thosewith AP narrowing only (Table 1).

Fig. 1figure 1

Schematic of the classification of patients depending on DISE findings

Table 1 Demographic information of patients with RC and AP narrowing (n = 98)

Scores of clinical questionnaires about subjective sleep-related symptoms were examined to compare differences between patients with RC narrowing and those with AP narrowing. Our questionnaire results show that the ESS and PSQI scores of patients with RC narrowing were higher than those of patients with AP narrowing, whereas the BDI scores in the two groups were similar (Fig. 2). These clinical data show that patients with RC narrowing showed a relatively higher BMI and more severe subjective symptoms, including daytime sleepiness.

Fig. 2figure 2

Comparison of subjective symptoms of patients based on sleep questionnaires, Comparison of Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI) between patients with RC narrowing (red circle) and those with AP narrowing (blue circle). Statistics performed by t-test, * p < .05

Comparison of sleep parameters in RC narrowing vs. AP collapse

Our PSG data showed that 28% of patients with AP narrowing had moderate OSA, and 45% of them had severe OSA. On the other hand, 22% of patients with RC narrowing had moderate OSA, and the proportion of patients with severe OSA was higher (59%), although the difference was not statistically significant (Fig. 3).

Fig. 3figure 3

Comparison of OSA severity based on AHI score. The severity of OSA was compared in patients with AP (Lt) and RC narrowing (Rt).

Polysomnography parameters between patients with RC narrowing and those with AP narrowing were compared. The mean AHI score was 41.2 ± 27.3 (events/hr) in patients with RC narrowing, which was significantly higher than that of patients with AP narrowing (30.7 ± 20.9 (events/hr); p = 0.036) (Table 2). In addition, supine AHI, non-supine AHI, and REM sleep AHI scores were all significantly higher in patients with RC narrowing (p = 0.048, p = 0.002, and p = 0.006, respectively). Although no statistical significance was observed in other sleep parameters, indexes related to arousals were relatively higher, and values related to oxygen saturation were relatively lower in patients with RC narrowing than those with AP narrowing.

Table 2 Sleep parameters in patients depending on RC and AP narrowing during sleep

Multiple linear regression was performed to test if polysomnography parameters significantly predicted OSA severity as determined by AHI. In patients with RC narrowing, the fitted regression model was: AHI = 375.128–4.217*average SpO2 + 1.849*BMI (R2 = 0.842, F = 58.556, p < 0.001). Lower average SpO2 significantly predicted OSA severity (ß = -4.217, p < 0.001). Furthermore, BMI also significantly predicted OSA severity in patients with RC narrowing (ß = 1.849, p = 0.012). In patients with AP narrowing, the fitted regression model was: AHI = 364.039–3.606*average SpO2 (R2 = 0.814, F = 78.658, p < 0.001). Lower average SpO2 was the only significant predictor of increased AHI (ß = -3.606, p < 0.001).

These results support the hypothesis that patients with RC narrowing exhibit more aggravated sleep parameters than patients with AP narrowing, which could be associated with an increase in OSA severity.

Comparison of clinical characteristics and polysomnography parameters in RC narrowing according to the degree of narrowing

Among the 51 patients confirmed to have RC narrowing during sleep, 26 were confirmed to have grade 1 RC narrowing, and 25 were classified into grade 2. No statistically significant differences were observed between those two groups in sex, weight, or BMI. However, the mean age (52.4 years old) of patients with grade 2 RC was higher than that of those with grade 1 narrowing (45.5 years old), although statistical significance was not reached (p = 0.060) (Table 3). We found that subjective symptoms of patients with RC narrowing did not vary significantly with the degree of narrowing (Fig. 4). However, the polysomnography parameters were significantly higher in patients with higher degree of obstruction. The mean AHI was 51.7 ± 26.3 (events/hr) in patients with grade 2 RC narrowing, while it was 31.1 ± 24.7 (events/hr) in those with grade 1 narrowing (p = 0.006) (Table 4). Furthermore, supine AHI, and NREM AHI scores were all significantly elevated in patients with grade 2 RC narrowing (p = 0.001 and p = 0.007, respectively). The longest apnea time was significantly longer in patients with grade 2 RC narrowing than in those with grade 1 RC narrowing (p < 0.001) (Table 4). Similar to AHI results, the mean RDI was significantly higher in patients with grade 2 narrowing (p < 0.006). Values related to sleep oxygen saturation (average SpO2, minimum SpO2, and % of sleep SpO2 < 90%) were significantly lower in patients with grade 2 RC narrowing (p < 0.001, p = 0.002, and p < 0.001, respectively). The current findings indicate that polysomnography parameters related to apneic events and hypoxemia become more aggravated according to the degree of oropharyngeal obstruction during sleep in patients with RC narrowing.

Table 3 Demographic information of recruited OSA subjects with RC narrowing (n = 51)Fig. 4figure 4

Comparison of subjective symptoms in patients with RC narrowing, based on the sleep questionnaires. Comparison of Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI) between patients with grade 2 (red circle) and grade 3 RC narrowing (blue circle). Statistics performed by Mann Whitney U-test., * p < .05

Table 4 Sleep parameters in OSA subjects with RC narrowing depending on the degreePolysomnography parameters in LPW collapse only

Among the 106 patients with OSA, 8 were confirmed to have only LPW collapse. The mean BMI of the patients with only LPW collapse was 27.8 ± 3.5 kg/cm2 and the mean AHI was 50.2 (events/hr), which was higher than patients with RC narrowing, but that difference was not statistically significant (Fig. 5A). In addition, neither the average nor minimal O2 saturation differed between patients with RC narrowing and those with only LPW collapse (Fig. 5B, 5C). Furthermore, the proportion of patients with loud snoring was higher in those with LPW collapse only (Fig. 5D). Specifically, 75% of the patients with only LPW collapse during sleep exhibited greater than moderate degree (grade IV) of snoring, whereas only 53% of the patients in the RC narrowing group exhibited more than moderate degree of snoring. 48% of patients with RC narrowing showed low intensity snoring during sleep. The PSQI and BDI scores tended to be lower in patients with LPW collapse compared to those with RC narrowing; however, the difference was not statistically significant (Fig. 5E). Although more powered tests for direct comparison are warranted, sleep parameters and subjective sleep-related symptoms of patients with only LPW collapse may not differ greatly with RC narrowing except the intensity of snoring.

Fig. 5figure 5

Comparison of sleep parameters and sleep questionnaires between patients with RC narrowing and those with LPW collapse. (A) Apnea and hypopnea index, (B) average O2 saturation, and (C) lowest oxygen saturation during sleep were compared between patients with RC narrowing and those with LPW collapse. (D) The intensity of snoring was compared between patients with RC narrowing and those with LPW collapse. Patients with RC narrowing and those with LPW collapse completed the (E) Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI) (VAS: visual analogue scale). *: p < .05 between patients with RC narrowing (gray circle) and those with LPW collapse (red circle).

留言 (0)

沒有登入
gif