Effect of continuous positive airway pressure treatment on pulmonary artery pressure in patients with isolated obstructive sleep apnea: a meta-analysis

Pulmonary hypertension associated with lung diseases

Pulmonary hypertension (PH) associated with chronic lung disease (CLD) is both common and underrecognised. The presence of PH in the setting of lung disease has been consistently shown to be associated with worse outcomes. Recent epidemiological studies have advanced understanding of the heterogeneity of this patient population and shown that defining both the specific type of CLD as well as the severity of PH (i.e. deeper phenotyping) is necessary to inform natural history and prognosis. A systematic diagnostic approach to screening and confirmation of suspected PH in CLD is recommended. Numerous uncontrolled studies and one phase 3 randomised, controlled trial have suggested a benefit in treating PH in some patients with CLD, specifically those with fibrotic interstitial lung disease (ILD). However, other studies in diseases such as COPD-PH showed adverse outcomes with some therapies. Given the expanding list of approved pharmacological treatments for pulmonary arterial hypertension, developing a treatment algorithm for specific phenotypes of CLD-PH is required. This article will summarise existing data in COPD, ILD and other chronic lung diseases, and provide recommendations for classification of CLD-PH and approach to the diagnosis and management of these challenging patients.

Obstructive Sleep Apnea, Obesity Hypoventilation Syndrome, and Pulmonary Hypertension: A State-of-the-Art Review

The pathophysiological interplay between sleep-disordered breathing (SDB) and pulmonary hypertension (PH) is complex and can involve a variety of mechanisms by which SDB can worsen PH. These mechanistic pathways include wide swings in intrathoracic pressure while breathing against an occluded upper airway, intermittent and/or sustained hypoxemia, acute and/or chronic hypercapnia, and obesity. In this review, we discuss how the downstream consequences of SDB can adversely impact PH, the challenges in accurately diagnosing and classifying PH in the severely obese, and review the limited literature assessing the effect of treating obesity, obstructive sleep apnea, and obesity hypoventilation syndrome on PH.

Hypoxic and Autonomic Mechanisms from Sleep-Disordered Breathing Leading to Cardiopulmonary Dysfunction

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder. Its prevalence has increased due to increasing obesity and improved screening and diagnostic strategies. OSA overlaps with cardiopulmonary diseases to promote intermittent hypoxia and autonomic dysfunction. Intermittent hypoxia increases the risk for oxidative stress and inflammation, which promotes endothelial dysfunction and predisposes to atherosclerosis and other cardiovascular complications. OSA is associated with an increased sympathetic nervous system drive resulting in autonomic dysfunction leading to worsening of cardiopulmonary diseases. Cardiovascular diseases are observed in 40% to 80% of OSA patients. Therefore, it is essential to screen and treat cardiovascular diseases.

Obstructive Sleep Apnea and Pulmonary Hypertension: A Chicken-and-Egg Relationship

Obstructive sleep apnea (OSA) is characterized by repeated episodes of upper airway obstruction during sleep, and it is closely linked to several cardiovascular issues due to intermittent hypoxia, nocturnal hypoxemia, and disrupted sleep patterns. Pulmonary hypertension (PH), identified by elevated pulmonary arterial pressure, shares a complex interplay with OSA, contributing to cardiovascular complications and morbidity. The prevalence of OSA is alarmingly high, with studies indicating rates of 20-30% in males and 10-15% in females, escalating significantly with age and obesity. OSA's impact on cardiovascular health is profound, particularly in exacerbating conditions like systemic hypertension and heart failure. The pivotal role of hypoxemia increases intrathoracic pressure, inflammation, and autonomic nervous system dysregulation in this interplay, which all contribute to PH's pathogenesis. The prevalence of PH among OSA patients varies widely, with studies reporting rates from 15% to 80%, highlighting the variability in diagnostic criteria and methodologies. Conversely, OSA prevalence among PH patients also remains high, often exceeding 25%, stressing the need for careful screening and diagnosis. Treatment strategies like continuous positive airway pressure (CPAP) therapy show promise in mitigating PH progression in OSA patients. However, this review underscores the need for further research into long-term outcomes and the efficacy of these treatments. This review provides comprehensive insights into the epidemiology, pathophysiology, and treatment of the intricate interplay between OSA and PH, calling for integrated, personalized approaches in diagnosis and management. The future landscape of OSA and PH management hinges on continued research, technological advancements, and a holistic approach to improving patient outcomes.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Prevention of Incident Hypertension in Patients With Obstructive Sleep Apnea Treated With Uvulopalatopharyngoplasty or Continuous Positive Airway Pressure: A Cohort Study

Purpose

To determine whether treatment with uvulopalatopharyngoplasty (UPPP) or continuous positive airway pressure (CPAP) in patients with obstructive sleep apnea (OSA) prevents hypertension, compared to those not receiving any treatment.

Methods

A retrospective cohort study was conducted among 413 patients with OSA (age ≥ 35 years) at the Shuang Ho Hospital between 2009 and 2016. The patients were divided into three groups: UPPP, CPAP, and non-treatment groups. Data about the personal characteristics, history of comorbidities, and polysomnography (PSG) reports were collected at baseline. A Cox model with inverse probability of treatment weighting was used to adjust for confounders and baseline diversity.

Results

After multivariate adjustment and weighting for incident hypertension, patients in both the CPAP and UPPP groups showed a significant preventive effect on hypertension than in the non-treatment group. Moreover, patients in the CPAP group had lower event rates than those in the UPPP group.

Conclusion

UPPP can prevent the development of new-onset hypertension in patients with OSA. CPAP had a better preventive effect than UPPP. UPPP might be a good alternative for reducing the risk of the onset of hypertension when compliance to CPAP is poor.

Sleep disorders in elderly population suffering from TB and respiratory diseases

Sleep disorders (SD) are more frequent in the elderly population than younger counterparts. The underlying SD has a more severe impact on cardiorespiratory fitness. In elderly population with respiratory disorders, incidence and baneful influence of sleep disorders are extremely high. Insomnia in elderly is very common probably due to age related changes, underlying co morbidities and multiple medications. With aging there is decrease in duration of slow wave sleep and increase in NREM stage 1 and 2 sleep, which increases number of spontaneous arousals. Compared to younger people, elderly individuals tend to sleep earlier and wake up earlier due to changes in their normal circadian rhythm. Poor sleep quality and restless leg syndrome are higher in Tuberculosis patients. Disturbances in immune regulation due to chronic insomnia may exacerbate chronic infections like TB. Because many respiratory diseases and medications are known to cause sleep disturbances, it is important to assess treatable medical conditions and insomnia inducing medications before initiating hypnotics. Diagnosing sleep disordered breathing (SDB) in ILD patients is particularly important as nocturnal oxygen desaturation is associated with poor prognosis and could possibly be a cause of pulmonary hypertension. In patients with pulmonary hypertension (PH) and underlying obstructive sleep apnoea, CPAP therapy may help to reduce the PH. Addressing sleep disorders will be highly beneficial in elderly COPD patients with sleep disorders. This article reviews different SD, its effects and the treatment benefits in improving the quality of life and reducing the risk of progression of respiratory dysfunction in elderly population with TB and respiratory diseases.

The association between sleep-related breathing disorders and pre-capillary pulmonary hypertension: A chicken and egg question

The level of knowledge about a direct link between sleep-related breathing disorders and pre-capillary pulmonary hypertension (PH) is low and there is a chicken and egg question to know which disease causes the other. On one hand, sleep-related breathing disorders are considered as a cause of group 3 PH, in the subgroup of patients with hypoxemia without lung disease. Indeed, isolated sleep-related breathing disorders can lead to mild pre-capillary PH on their own, although this is rare for obstructive sleep apnea and difficult to establish for obesity-hypoventilation syndrome, the evolution towards PH being observed especially in the presence of respiratory comorbidities. The hemodynamic improvement under treatment with continuous positive airway pressure or non-invasive ventilation also argues for a causal link between pre-capillary PH and sleep-related breathing disorders. On the other hand, patients followed for pre-capillary PH, particularly pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, develop more sleep-related breathing disorders than the general population, especially sleep hypoxemia, central sleep apnea in patients with severe PH and obstructive sleep apnea in older patients with higher body mass index. The main objective of this article is therefore to answer two main questions, which will then lead us to discuss the bilateral link between these diseases: are sleep-related breathing disorders independent risk factors for pre-capillary PH and does pre-capillary PH induce sleep-related breathing disorders? In other words, who is the chicken and who is the egg?

Sleep apnea and pulmonary hypertension: A riddle waiting to be solved

Obstructive sleep apnea (OSA) is an under-recognized yet highly prevalent disease that has major implications to cardiovascular health. Pulmonary hypertension (pH) is less common but none the less a fatal condition. The association of OSA and PH is a known but not well understood phenomenon. Furthermore, the relationship appears to be bi-directional with limited understanding of the mechanism(s) driving the processes. PH in OSA has real time consequences as it has been shown to increase mortality. Limited data suggests that treatment with continuous positive pressure therapy may be beneficial and reduce pulmonary pressure. In this review, we discuss current data on prevalence of PH in OSA and vice versa. We also explore the pathophysiology of this relationship and a proposed mechanism for their connection. Finally, we address the treatment of OSA with CPAP and its impact on pulmonary pressures. Gaps in knowledge and future research potential are illustrated and discoursed.

Cardiovascular Disorders Triggered by Obstructive Sleep Apnea-A Focus on Endothelium and Blood Components

Obstructive sleep apnea (OSA) is known to be an independent cardiovascular risk factor. Among arousal from sleep, increased thoracic pressure and enhanced sympathetic activation, intermittent hypoxia is now considered as one of the most important pathophysiological mechanisms contributing to the development of endothelial dysfunction. Nevertheless, not much is known about blood components, which justifies the current review. This review focuses on molecular mechanisms triggered by sleep apnea. The recurrent periods of hypoxemia followed by reoxygenation promote reactive oxygen species (ROS) overproduction and increase inflammatory response. In this review paper we also intend to summarize the effect of treatment with continuous positive airway pressure (CPAP) on changes in the profile of the endothelial function and its subsequent potential clinical advantage in lowering cardiovascular risk in other comorbidities such as diabetes, atherosclerosis, hypertension, atrial fibrillation. Moreover, this paper is aimed at explaining how the presence of OSA may affect platelet function and exert effects on rheological activity of erythrocytes, which could also be the key to explaining an increased risk of stroke.

Narrative review of sleep and pulmonary hypertension

Pulmonary hypertension (PH) is a condition of raised pulmonary artery pressure (PAP), which may be secondary to a number of causes, one of which is sleep disordered breathing (SDB). When PH complicates SDB, it carries a significant burden of morbidity and mortality due to the risk of progression to right ventricular failure over time. This narrative review will cover the definition and classification of PH, and explore the epidemiology of PH in SDB. The mechanisms by which the two conditions are linked will be reviewed. Repetitive hypoxia with or without hypercapnia alongside frequent arousals can result in important metabolic and pulmonary vascular consequences for the left and right heart. MEDLINE was used to search for all relevant articles and abstracts published from January 1960 to October 2019 inclusive (in all languages). Current best practice in the investigation and management of PH complicating SDB will be reviewed. Important diagnostic investigations and when to consider and screen further for PH in patients with SDB will be discussed. Optimal disease management must include control of SDB with therapy. Additional treatment options will be reviewed. Areas for further research will be highlighted.

Stim-activated TRPC-ORAI channels in pulmonary hypertension induced by chronic intermittent hypoxia

Obstructive sleep apnea (OSA), a breathing disorder featured by chronic intermittent hypoxia (CIH) is associated with pulmonary hypertension (PH). Rodents exposed to CIH develop pulmonary vascular remodeling and PH, but the pathogenic mechanisms are not well known. Overexpression of Stim-activated Transient Receptor Potential Channels (TRPC) and Calcium Release-Activated Calcium Channel Protein (ORAI) TRPC-ORAI Ca²⁺ channels (STOC) has been involved in pulmonary vascular remodeling and PH in sustained hypoxia. However, it is not known if CIH may change STOC levels. Accordingly, we studied the effects of CIH on the expression of STOC subunits in the lung and if these changes paralleled the progression of the vascular pulmonary remodeling and PH in a preclinical model of OSA. Male Sprague-Dawley rats (∼200 g) were exposed to CIH (5%O₂, 12 times/h for 8 h) for 14, 21, and 28 days. We measured right ventricular systolic pressure (RVSP), cardiac morphometry with MRI, pulmonary vascular remodeling, and wire-myographic arterial responses to KCl and endothelin-1 (ET-1). Pulmonary RNA and protein STOC levels of TRPC1, TRPC4, TRPC6, ORAI 1, ORAI 2, and STIM1 subunits were measured by qPCR and western blot, and results were compared with age-matched controls. CIH elicited a progressive increase of RVSP and vascular contractile responses to KCl and ET-1, leading to vascular remodeling and augmented right ventricular ejection fraction, which was significant at 28 days of CIH. The levels of TRPC1, TRPC4, TRPC 6, ORAI 1, and STIM 1 channels increased following CIH, and some of them paralleled morphologic and functional changes. Our findings show that CIH increased pulmonary STOC expression, paralleling vascular remodeling and PH.

Sleep-related breathing disorders and pulmonary hypertension

Sleep-related breathing disorders (SBDs) include obstructive apnoea, central apnoea and sleep-related hypoventilation. These nocturnal events have the potential to increase pulmonary arterial pressure (PAP) during sleep but also in the waking state. "Pure" obstructive sleep apnoea syndrome (OSAS) is responsible for a small increase in PAP whose clinical impact has not been demonstrated. By contrast, in obesity hypoventilation syndrome (OHS) or overlap syndrome (the association of chronic obstructive pulmonary disease (COPD) with obstructive sleep apnoea (OSA)), nocturnal respiratory events contribute to the development of pulmonary hypertension (PH), which is often severe. In the latter circumstances, treatment of SBDs is essential in order to improve pulmonary haemodynamics.Patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) are at risk of developing SBDs. Obstructive and central apnoea, as well as a worsening of ventilation-perfusion mismatch, can be observed during sleep. There should be a strong suspicion of SBDs in such a patient population; however, the precise indications for sleep studies and the type of recording remain to be specified. The diagnosis of OSAS in patients with PAH or CTEPH should encourage treatment with continuous positive airway pressure (CPAP). The presence of isolated nocturnal hypoxaemia should also prompt the initiation of long-term oxygen therapy. These treatments are likely to avoid worsening of PH; however, it is prudent not to treat central apnoea and Cheyne-Stokes respiration (CSR) with adaptive servo-ventilation in patients with chronic right-heart failure because of a potential risk of serious adverse effects from such treatment.In this review we will consider the current knowledge of the consequences of SBDs on pulmonary haemodynamics in patients with and without chronic respiratory disease (group 3 of the clinical classification of PH) and the effect of treatments of respiratory events during sleep on PH. The prevalence and consequences of SBDs in PAH and CTEPH (groups 1 and 4 of the clinical classification of PH, respectively), as well as therapeutic options, will also be discussed.

Longer apnea duration at low altitude in Tibetan and Han highlanders compared with Han lowlanders: A retrospective study

Prolonged duration of obstructive apnea (OA) has been observed in highlanders after descending to low altitude. It is proposed that due to adaptation to a hypoxic high-altitude environment, Tibetan highlanders (TH) and Han highlanders (HH) would manifest different OA durations at low altitude as compared to Han lowlanders (HL). Data collection on consecutive obstructive sleep apnea patients (167 TH, 210 HH and 233 HL) was performed over a period of 8 years in Chengdu (altitude 500 m). The analyses were performed with non-matched groups and with body mass index and apnea-hypopnea index-matched groups. Significance rankings for mean duration of OA (s) in non-matched groups and matched groups were TH (27.7; 28.6) = HH (25.7; 26.0) > HL (21.7; 21.3), respectively. For the longest OA duration, the significance rankings across three groups with regard to the percentage of patients having a duration longer than 2 min (%) and mean values (s) were TH (26.9; 82) > HH (10.0; 67) > HL (1.3; 50). In terms of nadir and mean oxygen saturation, significant differences were found between TH and HH or HL. In addition, longest and mean OA duration were positively correlated with blood pressure and heart rate, whereas nadir and mean oxygen saturation were negatively correlated with these measures in both non-matched and matched groups, and the correlation was more robust in TH. These findings raise important clinical questions regarding whether such significant prolongation of OA duration and a more severe hypoxic burden among highlanders, especially in TH, may lead to adverse clinical consequences when at low altitude.

Potential Contribution of Carotid Body-Induced Sympathetic and Renin-Angiotensin System Overflow to Pulmonary Hypertension in Intermittent Hypoxia

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA), featured by chronic intermittent hypoxia (CIH), is an independent risk for systemic hypertension (HTN) and is associated with pulmonary hypertension (PH). The precise mechanisms underlying pulmonary vascular remodeling and PH in OSA are not fully understood. However, it has been suggested that lung tissue hypoxia, oxidative stress, and pro-inflammatory mediators following CIH exposure may contribute to PH.

RECENT FINDINGS

New evidences obtained in preclinical OSA models support that an enhanced carotid body (CB) chemosensory reactiveness to oxygen elicits sympathetic and renin-angiotensin system (RAS) overflow, which contributes to HTN. Moreover, the ablation of the CBs abolished the sympathetic hyperactivity and HTN in rodents exposed to CIH. Accordingly, it is plausible that the enhanced CB chemosensory reactivity may contribute to the pulmonary vascular remodeling and PH through the overactivation of the sympathetic-RAS axis. This hypothesis is supported by the facts that (i) CB stimulation increases pulmonary arterial pressure, (ii) denervation of sympathetic fibers in pulmonary arteries reduces pulmonary remodeling and pulmonary arterial hypertension (PAH) in humans, and (iii) administration of angiotensin-converting enzyme (ACE) or blockers of Ang II type 1 receptor (ATR1) ameliorates pulmonary remodeling and PH in animal models. In this review, we will discuss the supporting evidence for a plausible contribution of the CB-induced sympathetic-RAS axis overflow on pulmonary vascular remodeling and PH induced by CIH, the main characteristic of OSA.

Sleep Apnea, the Risk of Developing Heart Failure, and Potential Benefits of Continuous Positive Airway Pressure (CPAP) Therapy

Background

Whether there is an association between sleep apnea (SA) and the risk of developing heart failure (HF) is unclear. Furthermore, it has never been established whether continuous positive airway pressure (CPAP) therapy can prevent development of HF. We aimed to investigate SA patients’ risk of developing HF and the association of CPAP therapy.

Methods and Results

Using nationwide databases, the entire Danish population was followed from 2000 until 2012. patients with SA receiving and not receiving CPAP therapy were identified and compared with the background population. The primary end point was first‐time hospital contact for HF and adjusted incidence rate ratios of HF were calculated using Poisson regression models. Among 4.9 million individuals included, 40 485 developed SA during the study period (median age: 53.4 years, 78.5% men) of whom 45.2% received CPAP therapy. Crude rates of HF were increased in all patients with SA relative to the background population. In the adjusted model, the incidence rate ratios of HF were increased in the untreated SA patients of all ages, compared with the background population. Comparing the CPAP‐treated patients with SA with the untreated patients with SA showed significantly lower incidence rate ratios of HF among older patients.

Conclusions

In this nationwide cohort study, SA not treated with CPAP was associated with an increased risk of HF in patients of all ages. Use of CPAP therapy was associated with a lower risk of incident HF in patients >60 years of age, suggesting a protective effect of CPAP therapy in the elderly.

Should the diagnosis and management of OSA move into general practice?

Sleep apnoea is a common disease that for accurate management requires the participation of primary care medicine http://ow.ly/G6Mq301zcaM.