Characterisation of Symptom and Polysomnographic Profiles Associated with Cardiovascular Risk in a Sleep Clinic Population with Obstructive Sleep Apnoea

Aim

Recent data have identified specific symptom and polysomnographic profiles associated with cardiovascular disease (CVD) in patients with obstructive sleep apnoea (OSA). Our aim was to determine whether these profiles were present at diagnosis of OSA in patients with established CVD and in those with high cardiovascular risk. Participants in the Sydney Sleep Biobank (SSB) database, aged 30-74 years, self-reported presence of CVD (coronary artery disease, cerebrovascular disease, or heart failure). In those without established CVD, the Framingham Risk Score (FRS) estimated 10-year absolute CVD risk, categorised as "low" (<6%), "intermediate" (6-20%), or "high" (>20%). Groups were compared on symptom and polysomnographic variables.

Results

629 patients (68% male; mean age 54.3 years, SD 11.6; mean BMI 32.3 kg/m2, SD 8.2) were included. CVD was reported in 12.2%. A further 14.3% had a low risk FRS, 38.8% had an intermediate risk FRS, and 34.7% had a high risk FRS. Groups differed with respect to age, sex and BMI. OSA severity increased with established CVD and increasing FRS. The symptom of waking too early was more prevalent in the higher FRS groups (p=0.004). CVD and FRS groups differed on multiple polysomnographic variables; however, none of these differences remained significant after adjusting for age, sex, and BMI.

Conclusion

Higher CVD risk was associated with waking too early in patients with OSA. Polysomnographic variations between groups were explained by demographic differences. Further work is required to explore the influence of OSA phenotypic characteristics on susceptibility to CVD.

User experience testing of the mobile pulmonary rehabilitation (m-PR™) app in people with chronic obstructive pulmonary disease

Objective

Mobile health (mHealth) technologies are emerging to support the delivery of pulmonary rehabilitation (PR). This study aimed to explore the ease of use, satisfaction and acceptability of an Australian mobile pulmonary rehabilitation app (m-PR™) in people with chronic obstructive pulmonary disease (COPD).

Methods

In this mixed methods observational study, participants with COPD were recruited following PR assessment. Participants were educated on m-PR™ which contained symptom monitoring, individualised exercise training with exercise videos, education videos, goal setting, health notifications and medication action plan. Participants used m-PR™ for 4-8 weeks. At baseline, participants were surveyed to assess level of technology engagement. At follow-up, participants completed the system usability survey (SUS), a satisfaction survey and a semi-structured interview.

Results

Fifteen participants (mean age 70 [SD 10] years, 53% female) completed the study. Technology usage was high with 73% (n = 11) self-rating their technology competence as good or very good. The SUS score of 71 (SD 16) demonstrated above average perceived usability of m-PR™. The satisfaction survey indicated that 67% (n = 10) enjoyed m-PR™ and 33% (n = 5) were neutral. Most participants found the different m-PR™ components somewhat easy or very easy to use (range 69-100%) and somewhat helpful or very helpful (range 76-100%). Interview responses revealed that m-PR™ elicited divergent feelings among participants, who reported both positive and negative feelings towards the app's features, the effort required to use it and data security.

Conclusion

The majority of participants found m-PR™ enjoyable, easy to use and helpful in managing their COPD. Further research is warranted to understand the effectiveness of mHealth to deliver PR.

Acceptability and barriers of a GP-physiotherapist partnership in the diagnosis and management of COPD in primary care: A qualitative study

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is commonly diagnosed and managed in primary care but there is evidence that this has been suboptimal, with low confidence expressed in providing interventions requiring behaviour change. The aim of this study was to determine the acceptability of a general practitioner (GP)-physiotherapist partnership in the diagnosis and management of COPD in primary care and to explore the experiences of participants during the implementation of the model.

METHODS

Semi-structured interviews were conducted with physiotherapists (n = 3), GPs (n = 2), practice nurses (PNs) (n = 2) and patients (n = 12) who had participated in the InNovaTivE Gp-physiotheRapist pArTnErship for copD (INTEGRATED) trial. We sought to explore participants' views about their experiences and perceived benefits, barriers and facilitators to the implementation of this model of care. Interviews were transcribed, coded and thematically analysed. Synthesis of the data was guided by the Theoretical Domains Framework for clinician interviews and the health belief model for patient interviews.

RESULTS

All clinicians felt that this integrated model helped to optimise care for patients with COPD by facilitating evidence-based practice. GPs and PNs valued the physiotherapist's knowledge and skills relating to diagnosis and management, which was reported to complement their own management and improve patient outcomes. Patients reported a sense of empowerment following their appointments and acknowledged improved self-management skills. However, physiotherapists reported many patients were already engaging in positive health behaviours. Responses were mixed on the effectiveness of the model in facilitating teamwork between clinicians with different perspectives concerning management, communication pathways and logistical issues, such as time and room availability, being cited as barriers.

CONCLUSIONS

An experienced cardiorespiratory physiotherapist embedded into a small number of primary care practices to work in partnership with GPs for COPD diagnosis and management was acceptable and viewed as beneficial for patients. Barriers relating to logistics and resources remain, which must be addressed to optimise implementation.

PATIENT OR PUBLIC CONTRIBUTION

Patient input was obtained from qualitative feedback from a prior study conducted by two authors and was used to refine the model of care to determine the added value of a physiotherapist integrated into the primary care team. This feedback was also used to refine the interview guides utilised in this study determine the acceptability of this model of care. We had health service involvement from the rehabilitation service of the local health district who were directly involved in determining study aims and establishing the project around the priorities for their chronic disease integration service. For example, this project aimed to engage with a less severe patient population in primary care who would benefit from pulmonary rehabilitation. The findings from this study will be used to further tailor the model of care to the needs of the public and patients.

TRIAL REGISTRATION

ACTRN12619001127190.

The effects of an innovative GP-physiotherapist partnership in improving COPD management in primary care

BACKGROUND

Evidence suggests that management of people with Chronic Obstructive Pulmonary Disease (COPD) in primary care has been suboptimal, in particular, with low referral rates to pulmonary rehabilitation (PR). The aim of this study was to evaluate the effectiveness of a GP-physiotherapist partnership in optimising management of COPD in primary care.

METHODS

A pragmatic, pilot, before and after study was conducted in four general practices in Australia. A senior cardiorespiratory physiotherapist was partnered with each general practice. Adults with a history of smoking and/or COPD, aged ≥ 40 years with ≥ 2 practice visits in the previous year were recruited following spirometric confirmation of COPD. Intervention was provided by the physiotherapist at the general practice and included PR referral, physical activity and smoking cessation advice, provision of a pedometer and review of inhaler technique. Intervention occurred at baseline, one month and three months. Main outcomes included PR referral and attendance. Secondary clinical outcomes included changes in COPD Assessment Test (CAT) score, dyspnoea, health activation and pedometer step count. Process outcomes included count of initiation of smoking cessation interventions and review of inhaler technique.

RESULTS

A total of 148 participants attended a baseline appointment where pre/post bronchodilator spirometry was performed. 31 participants with airflow obstruction on post-bronchodilator spirometry (mean age 75yrs (SD 9.3), mean FEV₁% pred = 75% (SD 18.6), 61% female) received the intervention. At three months, 78% (21/27) were referred to PR and 38% (8/21) had attended PR. No significant improvements were seen in CAT scores, dyspnoea or health activation. There was no significant change in average daily step count at three months compared to baseline (mean difference (95% CI) -266 steps (-956 to 423), p = 0.43). Where indicated, all participants had smoking cessation interventions initiated and inhaler technique reviewed.

CONCLUSION

The results of this study suggest that this model was able to increase referrals to PR from primary care and was successful in implementing some aspects of COPD management, however, was insufficient to improve symptom scores and physical activity levels in people with COPD.

TRIAL REGISTRATION

ANZCTR, ACTRN12619001127190. Registered 12 August 2019 - Retrospectively registered, http://www.ANZCTR.org.au/ACTRN12619001127190.aspx .

The Complex Association between COPD and COVID-19

Chronic obstructive pulmonary disease (COPD) is significant cause of morbidity and mortality worldwide. There is mounting evidence suggesting that COPD patients are at increased risk of severe COVID-19 outcomes; however, it remains unclear whether they are more susceptible to acquiring SARS-CoV-2 infection. In this comprehensive review, we aim to provide an up-to-date perspective of the intricate relationship between COPD and COVID-19. We conducted a thorough review of the literature to examine the evidence regarding the susceptibility of COPD patients to COVID-19 infection and the severity of their disease outcomes. While most studies have found that pre-existing COPD is associated with worse COVID-19 outcomes, some have yielded conflicting results. We also discuss confounding factors such as cigarette smoking, inhaled corticosteroids, and socioeconomic and genetic factors that may influence this association. Furthermore, we review acute COVID-19 management, treatment, rehabilitation, and recovery in COPD patients and how public health measures impact their care. In conclusion, while the association between COPD and COVID-19 is complex and requires further investigation, this review highlights the need for careful management of COPD patients during the pandemic to minimize the risk of severe COVID-19 outcomes.

Mobile Health Pulmonary Rehabilitation Compared to a Center-Based Program for Cost-Effectiveness and Effects on Exercise Capacity, Health Status, and Quality of Life in People with Chronic Obstructive Pulmonary Disease: A Protocol for a Randomized Controlled Trial

OBJECTIVE

A comprehensive digitalized program is a novel way to improve access to pulmonary rehabilitation for people with chronic obstructive pulmonary disease (COPD). This study aims to determine if a home-based pulmonary rehabilitation program supported by mobile health (mHealth) technology is equivalent to center-based pulmonary rehabilitation in terms of improvements in exercise capacity and health status in people with COPD.

METHODS

This study is a prospective, multicenter, equivalence randomized controlled trial (RCT) with intention-to-treat analysis. A hundred participants with COPD will be recruited from 5 pulmonary rehabilitation programs. Following randomization, participants will be assigned in a concealed manner to receive either home-based pulmonary rehabilitation supported by mHealth or center-based pulmonary rehabilitation. Both programs will be 8 weeks and will include progressive exercise training, disease management education, self-management support, and supervision by a physical therapist. Co-primary outcome measures will be the 6-Minute Walk Test and the COPD Assessment Test. Secondary outcome measures will include the St George's Respiratory Questionnaire, the EuroQol 5 Dimension 5 Level, the modified Medical Research Council dyspnea scale, the 1-minute sit-to-stand test, the 5 times sit-to-stand test, the Hospital Anxiety and Depression Scale, daily physical activity levels, health care utilization, and costs. Outcomes will be measured at baseline and at the end of the intervention. Participant experience will be assessed through semistructured interviews at the end of the intervention. Utilization of health care and costs will also be measured again after 12 months.

IMPACT

This study will be the first rigorous RCT to examine the effects of a home-based pulmonary rehabilitation program supported by mHealth technology that includes comprehensive clinical outcome evaluation, assessment of daily physical activity, a health economic analysis, and qualitative analysis. If findings demonstrate that there is equivalence in clinical outcomes, that the mHealth program costs the least amount (and is thus cost-effective), and that the mHealth program is acceptable to participants, such programs should be widely implemented to improve access to pulmonary rehabilitation.

Identifying airway obstruction in primary care: is there a role for physiotherapists?

Aims

To examine the implementation of a physiotherapist-driven spirometry case finding service in primary care to identify new cases of COPD and confirm diagnosis of existing cases of COPD.

Methods

Four general practices were recruited. ‘At risk’ participants (aged ≥ 40 years, current/ex-smoker) and people with ‘existing’ COPD were identified from practice databases and invited to attend an assessment with a cardiorespiratory physiotherapist in each general practice. The physiotherapist performed pre/post-bronchodilator spirometry to identify or confirm a diagnosis of COPD (FEV1/FVC < 0.7). Outcome measures included number (%) of new cases of COPD, number (%) confirmed diagnosis of COPD and number (%) of high quality spirometry assessments with accurate interpretation.

Results

One hundred forty eight participants (mean age 70 years (SD 11.1), 57% female) attended a baseline assessment (117 ‘at risk’, 31’existing’ COPD) from 748 people invited. Physiotherapists performed 145 pre/post bronchodilator spirometry assessments. Obstruction on post-bronchodilator spirometry was confirmed in 17% (19/114) of ‘at risk’ and 77% (24/31) of ‘existing’ COPD. Majority of cases were classified as GOLD Stage II (63%, n = 27). Quality of pre/post bronchodilator spirometries for FEV1 were classified as A (68%), B (19%) and C (5%).

Conclusion

Physiotherapists integrated into primary care performed high quality spirometry testing, successfully case finding ‘at risk’ patients and identifying potential misdiagnosis of obstruction in some ‘existing’ COPD cases.

Trial registration

ANZCTR, ACTRN12619001127190. Registered 12 August 2019 – Retrospectively registered, http://www.ANZCTR.org.au/ACTRN12619001127190.aspx

Mandibular Advancement Splint Therapy

Mandibular advancement splint (MAS) therapy is the leading alternative to continuous positive airway pressure (CPAP) therapy for the treatment of obstructive sleep apnoea. A MAS is an oral appliance which advances the mandible in relation to the maxilla, thus increasing airway calibre and reducing collapsibility. Although it is less effective than CPAP in reducing the apnoea-hypopnoea index (AHI), it has demonstrated equivalence to CPAP in a number of key neurobehavioural and cardiovascular health outcomes, perhaps due to increased tolerability and patient adherence when compared to CPAP. However, response to MAS is variable, and reliable prediction tools for patients who respond best to MAS therapy have thus far been elusive; this is one of the key clinical barriers to wider uptake of MAS therapy. In addition, the most effective MAS devices are custom-made by a dentist specialising in the treatment of sleep disorders, which may present financial or accessibility barriers for some patients. MAS devices are generally well tolerated but may have side effects including temporomandibular joint (TMJ) dysfunction, hypersalivation, tooth pain and migration as well as occlusal changes. A patient-centred approach to treatment from a multidisciplinary team perspective is recommended. Evidence-based clinical practice points and areas of future research are summarised at the conclusion of the chapter.

COVID-19 rehabilitation delivered via a telehealth pulmonary rehabilitation model: a case series

International statements have suggested the pulmonary rehabilitation (PR) model as an appropriate rehabilitation option for people recovering from coronavirus disease 2019 (COVID-19). In this case series, we present our COVID-19 telehealth rehabilitation programme, delivered within a PR setting, and discuss the management of our first three cases. All patients were male, with a median age of 73 years. Following hospital discharge, the patients presented with persistent limitations and/or symptoms (e.g. breathlessness, fatigue, and reduced exercise capacity) which warranted community-based rehabilitation. Patients were assessed and provided with an initial six-week rehabilitation programme supported via telehealth using a treatable traits approach. Patients demonstrated improvements in exercise capacity and breathlessness; however, fatigue levels worsened in two cases and this was attributed to the difficulties of managing returning to work and/or carer responsibilities whilst trying to recover from a severe illness. We found that PR clinicians were well prepared and able to provide an individualized rehabilitation programme for people recovering from COVID-19.

The feasibility of an innovative GP-physiotherapist partnership to identify and manage chronic obstructive pulmonary disease (INTEGRATED): study protocol

BACKGROUND

Chronic obstructive pulmonary disease (COPD) contributes significantly to mortality, hospitalisations and health care costs worldwide. There is evidence that the detection, accurate diagnosis and management of COPD are currently suboptimal in primary care. Physiotherapists are well-trained in cardiorespiratory management and chronic care but are currently underutilised in primary care. A cardiorespiratory physiotherapist working in partnership with general practitioners (GPs) has the potential to improve quality of care for people with COPD.

METHODS

A prospective pilot study will test the feasibility of an integrated model of care between GPs and physiotherapists to improve the diagnosis and management of people with COPD in primary care. Four general practices will be selected to work in partnership with four physiotherapists from their local health district. Patients at risk of developing COPD or those with a current diagnosis of COPD will be invited to attend a baseline assessment with the physiotherapist, including pre- and post-bronchodilator spirometry to identify new cases of COPD or confirm a current diagnosis and stage of COPD. The intervention for those with COPD will involve the physiotherapist and GP working in partnership to develop and implement a care plan involving the following tailored to patient need: referral to pulmonary rehabilitation (PR), physical activity counselling, medication review, smoking cessation, review of inhaler technique and education. Process outcomes will include the number of people invited and reviewed at the practice, the proportion with a new diagnosis of COPD, the number of patients eligible and referred to PR and the number who attended PR. Patient outcomes will include changes in symptoms, physical activity levels, smoking status and self-reported exacerbations.

DISCUSSION

If feasible, we will test the integration of physiotherapists within the primary care setting in a cluster randomised controlled trial. If the model improves health outcomes for the growing numbers of people with COPD, then it may provide a GP-physiotherapist model of care that could be tested for other chronic conditions.

TRIAL REGISTRATION

ANZCTR, ACTRN12619001127190. Registered on 12 August 2019-retrospectively registered.

Mandibular advancement splints for the treatment of obstructive sleep apnea

Introduction: Obstructive sleep apnea (OSA) is a chronic condition which requires a comprehensive chronic disease management model, rather than a device-focused approach, so as to achieve the best possible health outcomes. Oral appliances are the main alternative to continuous positive airway pressure (CPAP) for the treatment of OSA. There has been an expansion of the research evidence to support the use of oral appliances in clinical practice and the clinical use of oral appliances for the treatment of OSA has become a mainstream practice.Areas covered: This review summarizes the evidence base for the use of oral appliances for the treatment of OSA. The types of oral appliances; their mechanism of action and clinical efficacy for the treatment of OSA; adverse effects, and the impact on patient acceptability and treatment adherence; and clinical effectiveness and health outcomes are discussed.Expert opinion: Personalization of treatment is vitally important in OSA and is a pre-requisite for optimizing adherence with treatment which, in turn, is a key determinant of clinical effectiveness. Treatment of OSA with mandibular advancement splints could provide an equivalent health benefit to CPAP despite not achieving a complete normalization of polysomnographic indices, mediated by differences in adherence profiles.

Awake Multimodal Phenotyping for Prediction of Oral Appliance Treatment Outcome

STUDY OBJECTIVES

An oral appliance (OA) is a validated treatment for obstructive sleep apnea (OSA). However, therapeutic response is not certain in any individual and is a clinical barrier to implementing this form of therapy. Therefore, accurate and clinically applicable prediction methods are needed. The goal of this study was to derive prediction models based on multiple awake assessments capturing different aspects of the pharyngeal response to mandibular advancement. We hypothesized that a multimodal model would provide robust prediction.

METHODS

Patients with OSA (apnea-hypopnea index [AHI] > 10 events/h) were recruited for treatment with a customized OA (n = 142, 59% male). Participants underwent facial photography (craniofacial structure), spirometry (mid-inspiratory flow at 50% vital capacity [MIF₅₀] and mid-expiratory flow at 50% vital capacity [MEF₅₀] and the ratio MEF₅₀/MIF₅₀) and nasopharyngoscopy (velopharyngeal collapse with Mueller maneuver and mandibular advancement). Treatment response was defined by 3 criteria: (1) AHI < 5 events/h plus ≥ 50% reduction, (2) AHI < 10 events/h plus ≥ 50% reduction, (3) ≥ 50% AHI reduction. Multivariable regression models were used to assess predictive utility of phenotypic assessments compared to clinical characteristics alone (age, sex, obesity, baseline AHI).

RESULTS

Craniofacial structure and flow-volume loops predicted treatment response. Accuracy of the prediction models (area under the receiver operating characteristic curve) for each criterion were 0.90 (criterion 1), 0.79 (criterion 2), and 0.78 (criterion 3). However, these prediction models including phenotypic assessments did not provide a statistically significant improvement over clinical predictors only.

CONCLUSIONS

Multimodal awake phenotyping does not enhance OA treatment outcome prediction. These office-based, awake assessments have limited utility for robust clinical prediction models. Future work should focus on sleep-related assessments.

COMMENTARY

A commentary on this article appears in this issue on page 1837.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry, Title: Multimodal phenotyping for the prediction of oral appliance treatment outcome in obstructive sleep apnoea, Identifier: ACTRN12611000409976, URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=336663.

Qualitative assessment of awake nasopharyngoscopy for prediction of oral appliance treatment response in obstructive sleep apnoea

PURPOSE

Clinical methods to identify responders to oral appliance (OA) therapy for obstructive sleep apnoea (OSA) are needed. Awake nasopharyngoscopy during mandibular advancement, with image capture and subsequent processing and analysis, may predict treatment response. A qualitative assessment of awake nasopharyngoscopy would be simpler for clinical practice. We aimed to determine if a qualitative classification system of nasopharyngoscopic observations reflects treatment response.

METHODS

OSA patients were recruited for treatment with a customised two-piece OA. A custom scoring sheet was used to record observations of the pharyngeal airway (velopharynx, oropharynx, hypopharynx) during supine nasopharyngoscopy in response to mandibular advancement and performance of the Müller manoeuvre. Qualitative scores for degree (< 25%, 25-50%, 50-75%, > 75%), collapse pattern (concentric, anteroposterior, lateral) and diameter change (uniform, anteroposterior, lateral) were recorded. Treatment outcome was confirmed by polysomnography after a titration period of 14.6 ± 9.8 weeks. Treatment response was defined as (1) Treatment AHI < 5, (2) Treatment AHI < 10 plus > 50% AHI reduction and (3) > 50% AHI reduction.

RESULTS

Eighty OSA patients (53.8% male) underwent nasopharyngoscopy. The most common naspharyngoscopic observation with mandibular advancement was a small (< 50%) increase in velopharyngeal lateral diameter (37.5%). The majority of subjects (72.5%) were recorded as having > 75% velopharyngeal collapse on performance of the Müller manoeuvre. Mandibular advancement reduced the observed level of pharyngeal collapse at all three pharyngeal regions (p < 0.001). None of the nasopharyngoscopic qualitative scores differed between responder and non-responder groups.

CONCLUSION

Qualitative assessment of awake nasopharyngoscopy appears useful for assessing the effect of mandibular advancement on upper airway collapsibility. However, it is not sensitive enough to predict oral appliance treatment outcome.

Australian and New Zealand Pulmonary Rehabilitation Guidelines

BACKGROUND AND OBJECTIVE

The aim of the Pulmonary Rehabilitation Guidelines (Guidelines) is to provide evidence-based recommendations for the practice of pulmonary rehabilitation (PR) specific to Australian and New Zealand healthcare contexts.

METHODS

The Guideline methodology adhered to the Appraisal of Guidelines for Research and Evaluation (AGREE) II criteria. Nine key questions were constructed in accordance with the PICO (Population, Intervention, Comparator, Outcome) format and reviewed by a COPD consumer group for appropriateness. Systematic reviews were undertaken for each question and recommendations made with the strength of each recommendation based on the GRADE (Gradings of Recommendations, Assessment, Development and Evaluation) criteria. The Guidelines were externally reviewed by a panel of experts.

RESULTS

The Guideline panel recommended that patients with mild-to-severe COPD should undergo PR to improve quality of life and exercise capacity and to reduce hospital admissions; that PR could be offered in hospital gyms, community centres or at home and could be provided irrespective of the availability of a structured education programme; that PR should be offered to patients with bronchiectasis, interstitial lung disease and pulmonary hypertension, with the latter in specialized centres. The Guideline panel was unable to make recommendations relating to PR programme length beyond 8 weeks, the optimal model for maintenance after PR, or the use of supplemental oxygen during exercise training. The strength of each recommendation and the quality of the evidence are presented in the summary.

CONCLUSION

The Australian and New Zealand Pulmonary Rehabilitation Guidelines present an evaluation of the evidence for nine PICO questions, with recommendations to provide guidance for clinicians and policymakers.

Frequent occurrence of gastric cancer in Asian kindreds with Li-Fraumeni syndrome

Type of cancer and age of onset in individuals with inherited aberrations in the tumour suppressor gene TP53 are variable, possibly influenced by genetic modifiers and different environmental exposure. Since 2009, the modified Chompret criteria (MCC) have been used to identify individuals for TP53 mutation screening. Using the TP53 mutation database maintained by the International Agency for Research on Cancer (IARC), we investigated if the MCC, mainly developed for a Caucasian population, was also applicable in Asia. We identified several differences in Asian families compared with similar Caucasian cohorts, suggesting that identification and management of Li-Fraumeni syndrome in Asia do not completely mirror that of North America and Western Europe. Early gastric cancer (<40 years) may be considered a new addition to the MCC especially for Asian families.

Comparative effects of two oral appliances on upper airway structure in obstructive sleep apnea

STUDY OBJECTIVES

Oral appliances are increasingly being used for treatment of obstructive sleep apnea (OSA). Mandibular advancement splint (MAS) mechanically protrudes the mandible, while the tongue stabilizing device (TSD) protrudes and holds the tongue using suction. Although both appliances can significantly improve or ameliorate OSA, their comparative effects on upper airway structure have not been investigated.

DESIGN

Cohort study.

SETTING

Sleep Investigation Unit.

PATIENTS

39 patients undergoing oral appliance treatment for OSA.

INTERVENTIONS

OSA patients underwent magnetic resonance imaging (MRI) of the upper airway during wakefulness at baseline and with MAS and TSD in randomized order. Treatment efficacy was determined by polysomnography in a subset of 18 patients.

MEASUREMENTS AND RESULTS

Upper airway lumen and surrounding soft tissue structures were segmented using image analysis software. Upper airway dimensions and soft tissue centroid movements were determined. Both appliances altered upper airway geometry, associated with movement of the parapharyngeal fat pads away from the airway. TSD increased velopharyngeal lateral diameter to a greater extent (+0.35 ± 0.07 vs. +0.18 ± 0.05 cm; P<0.001) and also increased antero-posterior diameter with anterior displacement of the tongue (0.68 ± 0.04 cm; P<0.001) and soft palate (0.12 ± 0.03 cm; P<0.001). MAS resulted in significant anterior displacement of the tongue base muscles (0.35 ± 0.04 cm). TSD responders (AHI reduction ≥50%) increased velopharyngeal volume more than non-responders (+2.65 ± 0.9 vs. -0.44 ± 0.8 cm(3); P < 0.05). Airway structures did not differ between MAS responders and non-responders.

CONCLUSIONS

These results indicate that the patterns and magnitude of changes in upper airway structure differ between appliances. Further studies are warranted to evaluate the clinical relevance of these changes, and whether they can be used to predict treatment outcome.

Relationship between surface facial dimensions and upper airway structures in obstructive sleep apnea

STUDY OBJECTIVES

We hypothesized that the facial phenotype is closely linked to upper airway anatomy. The aim of this study was to investigate the relationship between surface facial dimensions and upper airway structures using magnetic resonance imaging (MRI) in subjects with obstructive sleep apnea (OSA).

DESIGN

Cohort study.

SETTING

Sleep investigation unit.

PATIENTS

Sixty-nine patients (apnea-hypopnea index > or = 10/h) underwent MRI as part of a study of upper airway anatomy in oral appliance therapy.

INTERVENTIONS

Measurements of a range of surface facial dimensions and upper airway soft tissue volumes were performed on the MR images using image-analysis software. Pearson correlation analyses were performed.

MEASUREMENTS AND RESULTS

Significant correlations were identified between a number of surface facial dimensions and neck circumference. Significant positive correlations were demonstrated between surface facial dimensions (including facial widths, facial heights, nose width, interocular and intercanthal widths) and upper airway structures. The strongest associations were between the tongue volume and the midface width (r = 0.70, P < 0.001), and lower-face width (r = 0.60, P <0.001). Surface facial dimensions in combination were also strong determinants for tongue volume (r2 = 0.69). Correlations between surface soft tissue thickness and upper airway soft tissue volumes occurred at the level of the midface but not at the level of the lower face.

CONCLUSIONS

This study demonstrates that there is a relationship between surface facial dimensions and upper airway structures in subjects with OSA. These findings support the potential role of surface facial measurements in anatomic phenotyping for OSA.

The effect of mandibular advancement on upper airway structure in obstructive sleep apnoea

BACKGROUND

The mechanisms by which mandibular advancement splints (MAS) improve obstructive sleep apnoea (OSA) are not well understood. This study aimed to evaluate the mechanism of action of MAS by assessing their effect on upper airway structure in patients with OSA.

METHODS

Patients were recruited from a sleep disorders clinic for treatment with a custom-made MAS. MRI of the upper airway was performed during wakefulness in the supine position, with and without the MAS.

RESULTS

Sixty-nine patients with OSA were recruited. Treatment with the MAS reduced the apnoea-hypopnoea index (AHI) from 27.0+/-14.7 events/h to 12.2+/-12.5 events/h (p<0.001). There was an increase in the total airway volume with mandibular advancement (16.5+/-0.7 cm(3) vs 18.1+/-0.8 cm(3); p<0.01) that occurred predominantly because of an increase in the volume of the velopharynx (5.7+/-0.3 cm(3) vs 6.5+/-0.3 cm(3); p<0.001). This increase in airway calibre was associated with an increase in the lower anterior facial height (6.8+/-0.1 cm vs 7.5+/-0.1 cm; p<0.001), reduction in the distance between the hyoid and posterior nasal spine (7.4+/-0.1 cm vs 7.2+/-0.1 cm; p<0.001), lateral displacement of the parapharyngeal fat pads away from the airway (right parapharyngeal fat pad 0.17+/-0.02 cm; left parapharyngeal fat pad 0.22+/-0.02 cm) and anterior movement of the tongue base muscles (0.33+/-0.03 cm). Subanalyses in responders and non-responders to MAS treatment showed that the increase in upper airway calibre with mandibular advancement occurred only in responders.

CONCLUSION

These results suggest that the mechanism of action of MAS is to increase the volume of the upper airway, predominantly by increasing the volume of the velopharynx, and this increased volume is associated with changes in the surrounding bony and soft tissue structures.

Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea: a prospective validation study

PURPOSE

Flow-volume curves have been shown to relate to upper airway physiology during sleep and may be useful for predicting the response to treatment of obstructive sleep apnea (OSA) with mandibular advancement splints (MAS). The aim of this study was to prospectively assess the potential clinical utility of a previously derived prediction method using flow-volume curves performed during wakefulness.

METHODS

Patients with newly diagnosed OSA interested in undertaking treatment with a custom-made MAS were approached to participate in the study. Response to treatment was defined by a 50% or greater reduction in the apnea-hypopnea index. Flow-volume curves were performed in the erect position prior to construction of the MAS.

RESULTS

Flow-volume curves were performed in 35 patients. Of these, 25 patients were responders, and 10 patients were non-responders. A combined cut-off of an inspiratory flow rate at 50% of vital capacity (MIF₅₀) less than 6.0 L/s and a ratio of the expiratory flow rate at 50% of vital capacity to MIF₅₀ of greater than 0.7 correctly classified 48.6% of the patients. It had a sensitivity of 36.0%, specificity of 80.0%, positive predictive value of 81.8%, and negative predictive value of 33.3%.

CONCLUSIONS

These results suggest that the previously derived prediction model, using flow-volume curves performed during wakefulness, was not sufficient to reliably predict the response to treatment of OSA with MAS. A combination of a functional assessment using flow-volume curves and a structural evaluation of the upper airway with imaging modalities may result in a prediction model with better performance characteristics.

Craniofacial phenotyping in obstructive sleep apnea--a novel quantitative photographic approach

STUDY OBJECTIVES

To compare the craniofacial morphological phenotype of subjects with and without obstructive sleep apnea (OSA) using a quantitative photographic analysis technique.

DESIGN

Case-control study; subgroup matched for body mass index (BMI) and sex.

SETTING

Sleep investigation unit in a university teaching hospital.

PATIENTS

114 subjects (93% Caucasian) with OSA (apnea-hypopnea index [AHI] > or = 10/h) and 66 controls (AHI < 10/h).

INTERVENTIONS

Standardized frontal-profile craniofacial photographic imaging performed prior to polysomnography. Photographs were analyzed for the computation of linear, angular, area and polyhedral volume measurements representing dimensions and relationships of the various craniofacial regions.

MEASUREMENTS AND RESULTS

Photographic craniofacial phenotypic differences were demonstrated between OSA and control subjects, including a range of measurements of the face, mandible, maxilla, eyes, nose, head and neck. After 1-for-1 subgroup matching for BMI and sex (51 subjects in each group), mandibular length 1 (6.21 +/- 0.08 [mean +/- SEM] vs. 6.58 +/- 0.08 cm, P = 0.006), mandibular-nasion angle 1 (35.0 +/- 0.48 vs. 36.7 +/- 0.37 degrees, P = 0.006) and anterior neck space area (10.2 +/- 0.53 vs. 12.2 +/- 0.52 cm2, P = 0.01) remained smaller in the OSA group. Mandibular width-length angle (88.0 +/- 0.75 vs. 85.3 +/- 0.54 degrees, P = 0.005) and face width-midface depth angle (72.3 +/- 0.44 vs. 70.7 +/- 0.39 degrees, P = 0.01) remained larger in the OSA group, whereas mandibular triangular area (39.2 +/- 0.63 vs. 41.7 +/- 0.74 cm2, P = 0.01) was smaller.

CONCLUSIONS

Craniofacial phenotypic differences in OSA in Caucasian subjects can be demonstrated using a photographic analysis technique.

Prediction of obstructive sleep apnea with craniofacial photographic analysis

STUDY OBJECTIVES

To develop models based on craniofacial photographic analysis for the prediction of obstructive sleep apnea (OSA).

DESIGN

Prospective cohort study.

SETTING

Sleep investigation unit in a university teaching hospital.

PATIENTS

One hundred eighty subjects (95.6% Caucasian) referred for the initial investigation of OSA were recruited consecutively.

INTERVENTIONS

Clinical assessment and frontal-profile craniofacial photographic analyses were performed prior to polysomnography. Prediction models for determining the presence of OSA (apnea-hypopnea index [AHI] > or =10) were developed using logistic regression analysis and classification and regression trees (CART).

MEASUREMENTS AND RESULTS

Obstructive sleep apnea was present in 63.3% of subjects. Using logistic regression, a model with 4 photographic measurements (face width, eye width, cervicomental angle, and mandibular length 1) correctly classified 76.1% of subjects with and without OSA (sensitivity 86.0%, specificity 59.1%, area under the receiver operating characteristics curve [AUC] 0.82). Combination of photographic and other clinical data improved the prediction (AUC 0.87), whereas prediction based on clinical assessment alone was lower (AUC 0.78). The optimal CART model provided a similar overall classification accuracy of 76.7%. Based on this model, 59.4% of the subjects were classified as either high or low risk with positive predictive value of 90.9% and negative predictive value of 94.7%, respectively. The remaining 40.6% of subjects have intermediate risk of OSA.

CONCLUSIONS

Craniofacial photographic analysis provides detailed anatomical data useful in the prediction of OSA. This method allows OSA risk stratification by craniofacial morphological phenotypes.

Dental appliance treatment for obstructive sleep apnea

Oral appliances for the treatment of obstructive sleep apnea (OSA) are worn during sleep to maintain the patency of the upper airway by increasing its dimensions and reducing its collapsibility. Oral appliances are a simpler alternative to continuous positive airway pressure (CPAP). Over the last decade, there has been a significant expansion of the evidence base to support the use of oral appliances, with robust studies demonstrating their efficacy. This work has been underpinned by the recognition of the importance of upper airway anatomy in the pathophysiology of OSA. The updated practice parameters of the American Academy of Sleep Medicine now recommend their use for mild-to-moderate OSA, or for patients with severe OSA who are unable to tolerate CPAP or refuse treatment with CPAP. Oral appliances have been shown to have a beneficial impact on a number of important clinical end points, including the polysomnographic indexes of OSA, subjective and objective measures of sleepiness, BP, aspects of neuropsychological functioning, and quality of life. Elucidation of the mechanism of action of oral appliances has provided insight into the factors that predict treatment response and may improve the selection of patients for this treatment modality. Longitudinal studies to characterize the long-term adverse effects of oral appliance use are now beginning to emerge. Although less efficacious than CPAP for improving the polysomnographic indexes of OSA, oral appliances are generally preferred by patients. This has the potential to translate to better patient adherence and may provide an equivalent health outcome.

Protocatechuic acid induces cell death in HepG2 hepatocellular carcinoma cells through a c-Jun N-terminal kinase-dependent mechanism

Protocatechuic acid (PCA), chlorogenic acid (CA) and luteolin (LT) are plant phenols found in Chinese medicinal herbs such as Lonicera japonica. Cytotoxicity assays showed that PCA, CA and LT (at 100 micromol/L) effectively killed the HepG2 hepatocellular carcinoma cells. Among these three naturally occurring compounds, only PCA was capable of stimulating the c-Jun N-terminal kinase (JNK) and p38 subgroups of the mitogen-activated protein kinase (MAPK) family. Coincidently, PCA-induced cell death was rescued by specific inhibitors for JNK and p38, while the cytotoxicities of CA and LT were partially eliminated by the antioxidant effect of N-acetyl-L-cysteine (NAC). Further investigation demonstrated that the aqueous extract of Lonicera japonica also triggered HepG2 cell death in a JNK-dependent manner, but the amount of PCA alone in this herbal extract was insufficient to contribute the subsequent cytotoxic effect. Collectively, our results suggest that PCA is a naturally occurring compound capable of inducing JNK-dependent hepatocellular carcinoma cell death.