Fetally-encoded GDF15 and maternal GDF15 sensitivity are major determinants of nausea and vomiting in human pregnancy

Human pregnancy is frequently accompanied by nausea and vomiting that may become severe and life-threatening, as in hyperemesis gravidarum (HG), the cause of which is unknown. Growth Differentiation Factor-15 (GDF15), a hormone known to act on the hindbrain to cause emesis, is highly expressed in the placenta and its levels in maternal blood rise rapidly in pregnancy. Variants in the maternal GDF15 gene are associated with HG. Here we report that fetal production of GDF15, and maternal sensitivity to it, both contribute substantially to the risk of HG. We found that the great majority of GDF15 in maternal circulation is derived from the feto-placental unit and that higher GDF15 levels in maternal blood are associated with vomiting and are further elevated in patients with HG. Conversely, we found that lower levels of GDF15 in the non-pregnant state predispose women to HG. A rare C211G variant in GDF15 which strongly predisposes mothers to HG, particularly when the fetus is wild-type, was found to markedly impair cellular secretion of GDF15 and associate with low circulating levels of GDF15 in the non-pregnant state. Consistent with this, two common GDF15 haplotypes which predispose to HG were associated with lower circulating levels outside pregnancy. The administration of a long-acting form of GDF15 to wild-type mice markedly reduced subsequent responses to an acute dose, establishing that desensitisation is a feature of this system. GDF15 levels are known to be highly and chronically elevated in patients with beta thalassemia. In women with this disorder, reports of symptoms of nausea or vomiting in pregnancy were strikingly diminished. Our findings support a causal role for fetal derived GDF15 in the nausea and vomiting of human pregnancy, with maternal sensitivity, at least partly determined by pre-pregnancy exposure to GDF15, being a major influence on its severity. They also suggest mechanism-based approaches to the treatment and prevention of HG.

High-temperature high-pressure calorimeter for studying gram-scale heterogeneous chemical reactions

We present an instrument for measuring pressure changes and heat flows of physical and chemical processes occurring in gram-scale solid samples under high pressures of reactive gases. Operation is demonstrated at 1232 °C under 33 bars of pure hydrogen. Calorimetric heat flow is inferred using a grey-box non-linear lumped-element heat transfer model of the instrument. Using an electrical calibration heater to deliver 900 J/1 W pulses at the sample position, we demonstrate a dynamic calorimetric power resolution of 50 mW when an 80-s moving average is applied to the signal. Integration of the power signal showed that the 900 J pulse energy could be measured with an average accuracy of 6.35% or better over the temperature range 150-1100 °C. This instrument is appropriate for the study of high-temperature metal hydride materials for thermochemical energy storage.

The impact of viral hepatitis-related hepatocellular carcinoma to post-transplant outcomes

Hepatocellular carcinoma (HCC) is the most common complication of HCV infection leading to liver transplantation. We evaluated the impact of aetiology of liver disease on patient and graft survival following liver transplantation for HCC. From the Scientific Registry of Transplant Recipients (2002-2011), all adults who underwent liver transplantation for HCC were retrospectively included. Aetiology of liver disease was grouped into HCV, HBV, HCV-HBV co-infection and nonviral liver disease. Of 8,733 liver transplant recipients with HCC, 5507 had HCV, 631 had HBV, 163 were co-infected, and 2432 had nonviral causes of liver disease. In follow-up (48 ± 32 months), 8.2% had graft failure and 29.5% died. The mean rates of graft failure were 9.5%, 4.7%, 6.1% and 6.4% in HCV, HBV, HCV-HBV co-infection and nonviral liver disease, respectively (P < 0.0001). Post-transplant mortality rate in patients with HBV was 20.2%, HCV 31.0%, HCV-HBV 28.5% and nonviral 28.5% (P < 0.0001). This difference was significant starting one year post-transplant and became even more prominent later in follow-up. Five-year post-transplant survival was 64.7% in HCV, 77.7% in HBV, 71.0% in HCV-HBV and 69.1% in nonviral HCC (P < 0.0001). A diagnosis of HCV in patients with HCC was also independently associated with an increased risk of both graft failure (adjusted hazard ratio = 1.84 (1.46-2.33), P < 0.0001) and mortality (1.35 (1.21-1.50), P < 0.0001) in multivariate analysis. Patients with HCV-related HCC are at higher risk of adverse post-transplant outcomes. These patients should be considered for preemptive interferon-free antiviral therapy prior to or immediately following liver transplantation.

The patient's journey with chronic hepatitis C from interferon plus ribavirin to interferon- and ribavirin-free regimens: a study of health-related quality of life

BACKGROUND

Interferon and ribavirin negatively impact health-related quality of life (HRQL) during treatment.

AIM

To compare the impact of interferon and/or ribavirin-containing regimens on HRQL to interferon- and ribavirin-free regimens.

METHODS

HRQL data from nine multinational phase 3 clinical trials of sofosbuvir (SOF)-based regimens with and without ledipasvir (LDV), pegylated interferon (IFN) or ribavirin (RBV) were used. The Short Form-36 (SF-36) HRQL questionnaire was administered to subjects prospectively at baseline, during treatment, and 12 and 24 weeks after treatment cessation.

RESULTS

A total of 3460 CH-C with SF-36 data were included (52.2 ± 10.3 years, 62.6% male, 73.6% treatment-naïve, 15.0% cirrhotic, 68.2% HCV genotype 1 and 20.1% genotype 3). Compared to baseline HRQL, at the end of treatment, severe HRQL decrements were noted in IFN + RBV ± SOF regimens (on average, -3.8 to -24.3 on a 0-100 scale for different HRQL domains), while moderate decrements were noted in SOF + RBV ± LDV (-2.8 to -8.6). In contrast, in SOF/LDV without RBV, HRQL improvements were noted during treatment (+2.3 to +5.2). By 12 weeks post-treatment, HRQL returned to baseline in IFN + RBV ± SOF (P > 0.05) and improved in all IFN-free arms (+2.6 to +7.8). In multivariate analysis, a lower end of treatment HRQL was associated with IFN + RBV + SOF and a higher end of treatment HRQL was associated with SOF/LDV. By post-treatment-12, SOF/LDV was additionally associated with higher mental health scores. These improvements in HRQL scores were maintained 24 weeks post-treatment.

CONCLUSIONS

Removing interferon and ribavirin has led to substantial improvement of health-related quality of life during treatment. This may result in better patient experience and higher adherence to treatment regimen.

Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.

Association of hepatitis C with insulin resistance and type 2 diabetes in US general population: the impact of the epidemic of obesity

Studies from tertiary care medical centres have linked hepatitis C virus (HCV) to the development of insulin resistance (IR) and type 2 diabetes. The aim of the study is to assess the relationship between HCV positivity and insulin resistance/diabetes in the US population. Three cycles of the National Health and Nutrition Examination Survey (NHANES) conducted between 1988 and 2008 were used. HCV infection was diagnosed using a positive serologic anti-HCV test. Additionally, diabetes was diagnosed as fasting blood glucose ≥126 mg/dL and/or the use of hypoglycaemic medications. Insulin resistance was defined as a homeostasis of model assessment (HOMA) score of >3.0. Logistic regression was used to estimate the odds ratios (ORs) of each of the potential risk factors for diabetes mellitus (DM). The SUDAAN 10.0 was used to run descriptive and regression analyses. A total of 39 506 individuals from three NHANES cycles (1988-1994, 1999-2004 and 2005-2008) with complete demographic and relevant clinical data were included. Over these three NHANES cycles, prevalence of hepatitis C did not significantly change. During the first NHANES cycle (1988-1994), insulin and diabetes were independently associated with hepatitis C. However, during the later study cycles (1998-2008), these associations were no longer significant. In contrast, other important known risk factors for diabetes and IR (male gender, non-Caucasian race, age and obesity) remained significant over all three NHANES cycles. Although HCV infection was independently associated with an increased risk of diabetes and IR in the US population over a decade ago, assessment of the later NHANES cycles shows that this relationship may have become diluted by the rapid rise of other risks for diabetes, specifically, the prevalence of obesity.

MEDI-573 as a novel approach to IGF-1R and IR-A signaling inhibition by blocking IGF ligands: Phase I PK/PD, safety data, and disease linkage studies in breast cancer

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Background: MEDI-573 is a dual-targeting human antibody that neutralizes IGF-I/-II ligands and inhibits IGF-1R and insulin receptor-A (IR-A) signaling pathways, which play a role in breast and other epithelial cancers. By sparing IR-B and its hybrid receptors, MEDI-573 is expected to achieve antitumor activity without perturbing glucose homeostasis.

Methods: In a 3 + 3 dose-escalation trial ( NCT00816361 ), patients with advanced solid tumors, KPS ≥ 60, received MEDI-573 as a weekly 1-hr IV infusion at 0.5, 1.5, 5, 10, or 15 mg/kg every 21 days. Objectives included determination of MTD, safety profile, pharmacokinetics (PK), pharmacodynamics, and tumor response. In a separate biomarker study, mRNA expression of IR-A and IR-B was compared in HR+/HER- breast cancers.

Results: Patients included 13M/12F (17 evaluable for efficacy at data cutoff); median age 59 yrs (range 37-78). No DLTs, drug-related SAEs, or significant toxicity patterns were reported. Forty-five AEs were considered treatment-related (% of patients): decreased appetite (28%), fatigue (24%), nausea (20%), diarrhea (16%), and anemia (12%). Hyperglycemia occurred in 2 patients, 1 with evidence of prestudy insulin resistance. No other significant changes in plasma glucose levels occurred. MEDI-573 had dose-proportionality, with AUC of 415 ± 165, 597 ± 298, and 1940 ± 904 d*μg/mL at 5, 10, and 15 mg/kg, respectively. Suppression of free IGF-1 and -2 was fully achieved at doses ≥ 5 mg/kg. Stable disease spanning ≥ 12 wks (range 12-36+) was seen in 6/17 patients. No antidrug antibodies were reported. In a study to identify breast cancer subsets that are dependent on IGF signaling, the IR-A:IR-B ratio was significantly higher in HR+/HER2- breast cancer than matched adjacent normal tissues and in proliferative luminal B than in luminal A breast cancer.

Conclusions: MEDI-573 showed acceptable safety and favorable PK profiles without significant changes in glucose levels. The IR-A:IR-B ratio supports a biomarker approach for MEDI-573 patient stratification. A biomarker-rich phase Ib/II study of MEDI-573 with an aromatase inhibitor in patients with advanced HR+/HER2- breast cancer opens in 2011.

The effect of low intensity pulsed ultrasound in a 3D ex vivo orthodontic model

OBJECTIVES

This study investigated the effects of low intensity pulsed ultrasound (LIPUS) on dentoalveolar structures during orthodontic force application using a novel organ culture system.

METHODS

Mandibles were dissected from 28-day-old male Sprague Dawley rats, sliced into 1.5mm and cultured at 37°C and 5% CO(2), prior to application of a 50g force to each mandible slice. Slices were randomly divided into three groups of control, 5 and 10min LIPUS application and cultured for five days before histological and histomorphometrical analysis.

RESULTS

Cementum and predentine thickness and subodontoblast and periodontal ligament cell counts were increased in the ultrasound groups, with increases statistically significant in the 10min treated groups. Odontoblasts remained viable during LIPUS exposure and osteoclast activity was increased by LIPUS.

CONCLUSIONS

LIPUS may influence remodelling of the dentine-pulp complex and associated tissues during orthodontic force application ex vivo.

Early detection of central airway lung cancer in smokers with silicosis

BACKGROUND

Smokers with silicosis are at increased risk of lung cancer.

OBJECTIVE

To evaluate the feasibility of using autofluorescence bronchoscopy after sputum examination for early detection of large airway lung cancer and factors associated with the presence of cancerous and pre-cancerous lesions among smokers with silicosis.

METHODS

Subjects at the pneumoconiosis clinic were recruited if they fulfilled the following criteria: 1) age ≥40 years, 2) smoking history of ≥20 pack-years and 3) confirmed diagnosis of silicosis. Sputum specimens were collected for cytology/cytometry examination and autofluorescence bronchoscopy was performed in subjects with an abnormal sputum result.

RESULTS

A total of 48 subjects were recruited during the study period. The mean age and smoking history were respectively 63 ± 10 years and 51 ± 30 pack-years. Intraepithelial lung cancers and pre-neoplastic lesions (squamous metaplasia or above) were detected in respectively 2 (4.2%) and 14 (29.2%) subjects. The proportions of current smokers (75.0% vs. 40.6%, P = 0.03) and asbestos exposure (37.5% vs. 9.4%, P = 0.04) were significantly higher in subjects with the above lesions compared with those without.

CONCLUSIONS

Sputum examination followed by autofluorescence bronchoscopy may be a useful way of identifying cancerous/pre-cancerous lesions among silicotic smokers. Current smoking and asbestos exposure were associated with these lesions.

Management and prevention of spontaneous pneumothorax using pleurodesis in Hong Kong

BACKGROUND

The practice of pleurodesis for the management and prevention of spontaneous pneumothorax (SP) is uncertain.

DESIGN

A retrospective multicentre analysis of patients admitted to 12 hospitals in Hong Kong with SP in 2004 and who subsequently underwent pleurodesis for the same episode.

RESULTS

Pleurodesis was performed in 394 episodes. Initial medical chemical pleurodesis was performed for 258 (65.5%) patients ('initial medical group'), while 136 (34.5%) underwent initial surgical pleurodesis ('initial surgical group'). Secondary spontaneous pneumothorax (SSP; 237 episodes, 60.2%) was the most common indication for pleurodesis; it was also performed after a first episode of primary spontaneous pneumothorax (PSP) in 22 episodes (5.6%). Tetracycline derivatives (172 episodes, 66.7%) were the most popular sclerosing agents in the initial medical group. Those in the initial medical group were older and were more likely to be males, have SSP, chronic obstructive pulmonary disease and a history of past pleurodesis (P < 0.05) compared to the initial surgical group. Compared to the tetracycline group, more patients who initially received talc slurry had the procedure performed by surgeons, had larger (≥2 cm) pneumothorax or required suction during initial drainage (P < 0.05).

CONCLUSIONS

Despite the availability of international guidelines, there is considerable variation in pleurodesis for SP.

Minocycline and talc slurry pleurodesis for patients with secondary spontaneous pneumothorax

SETTING

Few studies have evaluated the sclerosing efficacy of minocycline, and none have specifically compared its sclerosing efficacy and safety profiles with talc slurry in secondary spontaneous pneumothorax (SSP).

DESIGN

A retrospective analysis was conducted in patients with SSP who underwent chemical pleurodesis from January to December 2004 with minocycline or talc slurry in 12 public hospitals of Hong Kong.

RESULT

There were 121 episodes of minocycline pleurodesis and 64 episodes of talc slurry pleurodesis. Immediate procedural failure were similar in the minocycline and talc slurry groups (21.5% vs. 28.1%, P = 0.31). Presence of interstitial lung disease, ≥ 2 previous episodes of pneumothorax, requiring mechanical ventilation during pleurodesis and persistent air leak before pleurodesis were independently associated with procedural failure. Pain was experienced in respectively 44.6% and 37.5% of the minocycline and the talc slurry groups. Pain was more common in patients receiving high doses of talc (≥ 5 g; P = 0.03). Respiratory distress was found in respectively 1.7% and 1.6% of the minocycline and talc slurry groups.

CONCLUSION

Minocycline and talc slurry had comparable sclerosing efficacy in SSP, with immediate success rates of >70%. Pain was the most common adverse effect and respiratory distress was uncommon. Both appeared to be effective and safe for chemical pleurodesis in SSP.

Management of patients admitted with pneumothorax: a multi-centre study of the practice and outcomes in Hong Kong

OBJECTIVE

To examine the management practice of pneumothorax in hospitalised patients in Hong Kong, especially the choice of drainage options and their success rates, as well as the factors associated with procedural failures.

DESIGN

Retrospective study.

SETTING

Multi-centre study involving 12 public hospitals in Hong Kong.

PATIENTS

All adult patients admitted as an emergency in the year 2004 with a discharge diagnosis of 'pneumothorax' were included. Data on the management and outcomes of the various types of pneumothoraces were collected from their case records.

RESULTS

Altogether these patients had 1091 episodes (476 primary spontaneous pneumothoraces, 483 secondary spontaneous pneumothoraces, 87 iatrogenic pneumothoraces, and 45 traumatic pneumothoraces). Conservative treatment was offered in 182 (17%) episodes, which were more common among patients with small primary spontaneous pneumothoraces (71%). Simple aspiration was performed to treat 122 (11%) of such episodes, and had a success rate of 15%. Aspiration failure was associated with having a pneumothorax of size 2 cm or larger (odds ratio=3.7; 95% confidence interval, 1.2-11.5; P=0.03) and a smoking history (4.1; 1.2-14.3; P=0.03). Intercostal tube drainage was employed in 890 (82%) episodes, with a success rate of 77%. Failure of intercostal tube drainage was associated with application of suction (odds ratio=4.1; 95% confidence interval, 2.8-5.9; P<0.001) and presence of any tube complications (1.55; 1.0-2.3; P=0.03). Small-bore catheters (<14 French) were used in 12 (1%) of the episodes only. Tube complications were encountered in 214 (24%) episodes.

CONCLUSION

Notwithstanding recommendations from international guidelines, simple aspiration and intercostal tube drainage with small-bore catheters were not commonly employed in the management of hospitalised patients with the various types of pneumothoraces in Hong Kong.

A randomised controlled trial of nasal continuous positive airway pressure on insulin sensitivity in obstructive sleep apnoea

The effects of treatment of obstructive sleep apnoea (OSA) on glucose metabolism have been investigated previously with conflicting results. This study evaluated the impact of nasal continuous positive airway pressure (nCPAP) treatment of OSA on insulin sensitivity. Males with moderate/severe OSA and no significant comorbidity were randomised to a therapeutic or sham nCPAP treatment group for 1 week and then reassessed. Those who received therapeutic nCPAP were further evaluated at 12 weeks. Insulin sensitivity (K(itt)) was estimated by the short insulin tolerance test. Other evaluations included blood pressure, metabolic profile, urinary catecholamines and intra-abdominal fat. In total, 61 Chinese subjects were randomised. 31 subjects receiving therapeutic nCPAP showed an increase in K(itt) (6.6+/-2.9 to 7.6+/-3.2 % x min(-1); p = 0.017), while the 30 patients on sham CPAP had no significant change, and the changes in K(itt) were different between the two groups (p = 0.022). At 12 weeks, improvement in K(itt) was seen in 20 subjects with BMI >or=25 kg x m(-2) (median (interquartile range) 28.3 (26.6-31.5); p = 0.044), but not in the nine subjects with BMI<25 kg x m(-2), or the entire group. The findings indicate that therapeutic nCPAP treatment of OSA for 1 week improved insulin sensitivity in nondiabetic males, and the improvement appeared to be maintained after 12 weeks of treatment in those with moderate obesity.

Serum adipocyte-fatty acid binding protein level is elevated in severe OSA and correlates with insulin resistance

Obstructive sleep apnoea (OSA) is associated with insulin resistance and metabolic syndrome. There is evidence that adipocyte-fatty acid binding protein (A-FABP) may be involved in the development of cardiometabolic dysfunction. The present authors hypothesise that A-FABP is upregulated in OSA. A total of 124 males without hypertension, diabetes mellitus, hyperlipidaemia or cardiovascular disease were recruited and underwent polysomnography. Serum A-FABP levels showed significant positive correlations with duration of oxygen desaturation and minimal oxygen saturation, fasting insulin and insulin resistance index by homeostasis model assessment. When subjects were divided into tertiles according to apnoea/hypopnoea index (AHI), serum A-FABP levels were significantly higher in the group with AHI >/=34.4 events.h(-1) than the groups with AHI 13.2-34.4 events.h(-1) or with AHI <13.2 events.h(-1). Serum A-FABP levels were significantly higher in the AHI >/=34.4 group than obesity-matched subjects with AHI <34.4 events.h(-1). Serum adipocyte-fatty acid binding protein levels correlated with obstructive sleep apnoea and insulin resistance, independently of obesity, and were significantly higher in severe obstructive sleep apnoea. Adipocyte-fatty acid binding protein may play a role in obstructive sleep apnoea and metabolic dysfunction.

Obstructive sleep apnoea in Asia

Obstructive sleep apnoea (OSA) syndrome is the commonest sleep-related breathing disorder worldwide. In Asia, the prevalence of symptomatic OSA in middle-aged men and women is 4.1-7.5% and 2.1-3.2%, respectively. These prevalence rates are similar to those reported in Caucasian populations. Obesity, an established major risk factor for OSA, is less common among Asians, and the reported values of body mass indices (BMIs) of Asians with OSA are lower than in their Caucasian counterparts. However, these population-based studies have consistently demonstrated that obesity is still the major risk factor for OSA in Asians, while other studies have suggested that craniofacial structural factors may make a greater contribution towards development of OSA in Asians than in Caucasians. Sleep medicine is in a developmental stage in many Asian countries, and the condition is likely under-recognised. Although sleep laboratories have been set up in various countries in Asia, the availability of this service is very limited. Continuous positive airway pressure is available in most parts of Asia, but financial constraints may limit its utility. Oral appliances have been postulated to have a greater role in the management of OSA in Asian patients, as they are likely to have more modifiable factors in their craniofacial structures, but this is yet to be proven. There is a great need for research and health care development on sleep disordered breathing in Asia, and the solution will only come with efforts towards promotion of awareness of this condition in both professional and lay communities.

Dentofacial Characteristics of Chinese Obstructive Sleep Apnea Patients in Relation to Obesity and Severity

Objective: To evaluate dentofacial characteristics in relation to obesity and degree of severity of obstructive sleep apnea (OSA) in male Chinese patients and to elucidate the relationship between demographic parameters (age, body weight, height, and body mass index [BMI]) cephalometric parameters and OSA in these subjects.

Materials and Methods: Lateral cephalograms of 121 Chinese male patients in natural head posture were obtained. Based on BMI value, the patients were divided into three groups. Based on apnea-hypopnea index (AHI) value, the patients were divided into a mild-to-moderate and a severe group.

Results: The hyoid position and soft palate length were significantly different among the three obesity groups. Soft palate length was significantly longer (P &lt; .01) in the severe OSA group than in the mild-to-moderate OSA group. Tongue base was significantly more inferiorly placed (P &lt; .05) in the severe OSA group than in the mild-to-moderate OSA group. Craniocervical extension was significantly increased (P &lt; .05) in the severe OSA group. Statistically significant differences were found among the three obesity groups in mandibular length, mandibular body length, maxillary length, anterior cranial base length, and overbite. The multiple stepwise linear regression analysis identified body weight, lower posterior facial height, mandibular body length, craniocervical extension, and sella-hyoid distance as the significant predictive variables for AHI.

Conclusions: This study revealed the existence of craniofacial and upper airway soft tissue differences in relation to obesity and severity of OSA among male Chinese OSA patients. Body weight and certain cephalometric parameters were significant predictors of OSA in Chinese male subjects.

The clinical value of autofluorescence bronchoscopy for the diagnosis of lung cancer

The aim of this study was to evaluate the role of autofluorescence bronchoscopy (AFB) in the routine work-up of lung cancer. Consecutive patients with atypical or suspicious cells in sputum or bronchial aspirate, no localising abnormality on chest radiography and nondiagnostic white-light bronchoscopic (WLB) results were recruited. WLB and AFB were performed sequentially during the same session. All abnormal areas detected by WLB, AFB or both were sampled and the biopsy specimens sent for histological examination. Sixty-two patients were recruited within the 32-month study period. Seventeen had no endobronchial lesion detected. Among the 45 patients with endobronchial lesions, 37 had lesions with a histopathological grade of mild dysplasia or less; of the eight patients who had a lesion with a histological grade of moderate dysplasia or worse, five were found to have lung cancer, two invasive lung cancer and three an intra-epithelial neoplasm (severe dysplasia). Lesions showing moderate dysplasia or worse were more commonly found in patients with suspicious cells than in those with atypical cells on sputum examination. AFB was more sensitive than WLB (91 versus 58%) at detecting these lesions, but less specific (26 versus 50%). A combination of white-light and autofluorescence bronchoscopy can increase the diagnostic yield of this invasive procedure in patients exhibiting abnormal sputum cytology.

Effect of a non-adjustable oral appliance on upper airway morphology in obstructive sleep apnoea

BACKGROUND

To evaluate the effect of oral appliance (OA) on upper airway morphology and its relationship with treatment response in subjects with obstructive sleep apnoea (OSA).

METHODS

Symptomatic OSA subjects were recruited. Non-adjustable OA was custom made. Variables examined at baseline and while wearing the device at 2 months included polysomnographic data, computed tomographic measurements of upper airway cross sectional area at level of velopharynx (VA) and hypopharynx (HA), upper airway volume, and cephalometric parameters. Treatment outcome was based on post-treatment apnoea-hypopnoea index (AHI).

RESULTS

Forty patients were recruited and 23 (7 women) completed the study. They were middle-aged (49, 40-58 years) (median, interquartile range) and overweight (BMI 26, 23.3-29.5 kg/m2), with moderate OSA (AHI 26.4, 14.1-36). The overall post treatment AHI was 8.4 (2.4-12.5), with 14 (61%) patients showing good response (AHI<10), and the other 9 patients showing moderate response (>50% reduction in AHI but still 10). OA decreased the cross-sectional area of the HA (P=0.046), showed a trend of decreasing the ratio of cross-sectional area of the HA to cross-sectional area of the VA (P=0.053) and significantly increased the overall upper airway volume (P=0.006, n=11). No significant relationship between upper airway parameters and treatment outcome was identified.

CONCLUSIONS

OA altered upper airway morphometry towards a profile consistent with decreased propensity to collapse, which may thus have contributed to improvement of OSA.