Obstructive sleep apnoea and venous thromboembolism: pathophysiological links and clinical implications

Obstructive sleep apnea hypopnea syndrome and vascular lesions: An update on what we currently know

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is the most prevalent sleep and respiratory disorder. This syndrome can induce severe cardiovascular and cerebrovascular complications, and intermittent hypoxia is a pivotal contributor to this damage. Vascular pathology is closely associated with the impairment of target organs, marking a focal point in current research. Vascular lesions are the fundamental pathophysiological basis of multiorgan ailments and indicate a shared pathogenic mechanism among common cardiovascular and cerebrovascular conditions, suggesting their importance as a public health concern. Increasing evidence shows a strong correlation between OSAHS and vascular lesions. Previous studies predominantly focused on the pathophysiological alterations in OSAHS itself, such as intermittent hypoxia and fragmented sleep, leading to vascular disruptions. This review aims to delve deeper into the vascular lesions affected by OSAHS by examining the microscopic pathophysiological mechanisms involved. Emphasis has been placed on examining how OSAHS induces vascular lesions through disruptions in the endothelial barrier, metabolic dysregulation, cellular phenotype alterations, neuroendocrine irregularities, programmed cell death, vascular inflammation, oxidative stress and epigenetic modifications. This review examines the epidemiology and associated risk factors for OSAHS and vascular diseases and subsequently describes the existing evidence on vascular lesions induced by OSAHS in the cardiovascular, cerebrovascular, retinal, renal and reproductive systems. A detailed account of the current research on the pathophysiological mechanisms mediating vascular lesions caused by OSAHS is provided, culminating in a discussion of research advancements in therapeutic modalities to mitigate OSAHS-related vascular lesions and the implications of these treatment strategies.

The Association between Obstructive Sleep Apnea and Venous Thromboembolism: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

 Despite previous observational studies linking obstructive sleep apnea (OSA) to venous thromboembolism (VTE), these findings remain controversial. This study aimed to explore the association between OSA and VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), at a genetic level using a bidirectional two-sample Mendelian randomization (MR) analysis.

METHODS

 Utilizing summary-level data from large-scale genome-wide association studies in European individuals, we designed a bidirectional two-sample MR analysis to comprehensively assess the genetic association between OSA and VTE. The inverse variance weighted was used as the primary method for MR analysis. In addition, MR-Egger, weighted median, and MR pleiotropy residual sum and outlier (MR-PRESSO) were used for complementary analyses. Furthermore, a series of sensitivity analyses were performed to ensure the validity and robustness of the results.

RESULTS

 The initial and validation MR analyses indicated that genetically predicted OSA had no effects on the risk of VTE (including PE and DVT). Likewise, the reverse MR analysis did not find substantial support for a significant association between VTE (including PE and DVT) and OSA. Supplementary MR methods and sensitivity analyses provided additional confirmation of the reliability of the MR results.

CONCLUSION

 Our bidirectional two-sample MR analysis did not find genetic evidence supporting a significant association between OSA and VTE in either direction.

Changes in sleep-disordered breathing from the acute to the stable phase of pulmonary embolism: The ESAET study

BACKGROUND

/Objective: Sleep-disordered breathing (SDB) may change from the acute to stable phase of some cardiovascular disorders, but little is known whether these dynamic changes also exist in pulmonary embolism (PE). This study aimed to analyze the changes in the apnea-hypopnea index (AHI) from the acute to stable phase of PE as well as the factors associated.

PATIENTS/METHODS

We conducted a prospective, longitudinal and multicenter study of consecutive adults requiring hospitalization for non-hypotensive acute PE, with a protocol including clinical, imaging (transthoracic echocardiography [TTE] and computed tomography), blood tests and a sleep study within 48 h of diagnosis of PE. After 3 months of follow-up, the sleep study was repeated. Right ventricular (RV) dysfunction was defined according to TTE criteria.

RESULTS

One hundred and eleven patients (mean age [SD]: 63 [15] years; body mass index: 28.4 [4.7] kg/m2) were included. The initial AHI was 24.4 (21.8) events/h (AHI≥5: 82.8 %; AHI≥30: 33.3 %). Seventy-seven patients (69.4 %) had RV dysfunction. In the overall cohort, the AHI decreased by 8.7 events/h from the acute to stable phase (24.4/h vs. 15.7/h; p=0.013). Patients with RV dysfunction showed a greater decrease in AHI (mean decrease 12.3/h vs. 0.43/h). In the multivariable analysis a drop of an AHI≥5 events/hour was independently associated with the presence of initial RV dysfunction (hazard ratio 3.9; 95%CI 1.3 to 12.1).

CONCLUSIONS

In hemodynamically stable patients with acute PE, there is a transient but clinically significant decrease in the AHI from the acute to stable phase, particularly when initially presenting with RV dysfunction.

The impact of sleep apnea on primary reverse shoulder arthroplasty for the treatment of glenohumeral osteoarthritis

Introduction

As the prevalence of sleep apnea (SA) increases nationwide, large sample sized studies following primary reverse shoulder arthroplasty (RSA) in SA patients are scarce. Therefore, this study evaluated whether SA is associated with 1) longer in-hospital lengths of stay (LOS) 2) readmissions 3) medical complications and 4) costs.

Methods

A retrospective nationwide Medicare analysis from 2005 to 2014 was performed. Inclusion criteria were patients with SA undergoing RSA for the treatment of glenohumeral osteoarthritis. Study group patients were 1:5 ratio matched to controls yielding 6241 patients in the study and 31,179 in the comparison cohort. Logistic regression was used to calculate odds-ratios (OR) for readmissions and complications. A p-value less than 0.004 was significant.

Results

SA patients had significantly longer in-hospital LOS compared to their counterparts (3-days versus 2-days, p < 0.0001), but similar rates of 90-day readmissions (7.98% vs. 6.54%; OR: 1.00, p = 0.907). Patients with SA had significantly greater incidence and odds of 90-day medical complications (13.36% vs. 7.29%; OR: 1.42, p < 0.0001) and significantly higher 90-day costs ($16,529.16 vs. $14,789.15, p < 0.0001).

Conclusion

Patients with SA undergoing primary RSA for the treatment of glenohumeral OA have longer in-hospital LOS, increased medical complications, and costs of care. Readmissions were not more common.

Level of Evidence

III.

Obstructive Sleep Apnea and Venous Thromboembolism: Unraveling the Emerging Association

Oxidative stress has emerged as a significant contributor to skeletal muscle atrophy, influencing cellular processes that underlie muscle wasting. This review article delves into the intricate interplay between oxidative stress and muscle atrophy, shedding light on its mechanisms and implications. We begin by outlining the fundamental concepts of oxidative stress, delineating reactive oxygen species (ROS) and reactive nitrogen species (RNS), their sources, and the ensuing oxidative damage to cellular components. Subsequently, we delve into skeletal muscle atrophy, elucidating its diverse forms, molecular pathways, key signaling cascades, and the role of inflammation in exacerbating muscle wasting. Bridging these concepts, we explore the connections between oxidative stress and muscle atrophy, unveiling how oxidative stress impacts muscle protein synthesis and breakdown, perturbs cellular signaling pathways, and contributes to mitochondrial dysfunction. The review underscores the complexity of quantifying and interpreting oxidative stress markers, highlighting the challenges posed by the dynamic nature of oxidative stress and the presence of basal ROS levels. Addressing the specificity of oxidative stress markers, we emphasize the importance of selecting markers pertinent to muscle tissue and considering systemic influences. Standardization of experimental protocols emerges as a critical need to ensure consistency and reproducibility across studies. Looking ahead, we discuss the implications of oxidative stress in diverse scenarios, encompassing age-related muscle loss (sarcopenia), muscle wasting in chronic diseases like cancer cachexia, and disuse-induced muscle atrophy. Additionally, we delve into potential therapeutic strategies, including antioxidant supplementation, exercise, pharmacological interventions, nutritional approaches, and lifestyle modifications, as avenues to mitigate oxidative stress-driven muscle atrophy. The review concludes by outlining promising future directions in this field, calling for deeper exploration of specific oxidative stress markers, understanding the temporal dynamics of oxidative stress, validation through translational studies in humans, and the development of targeted therapeutic interventions. By advancing our understanding of the intricate relationship between oxidative stress and skeletal muscle atrophy, this review contributes to paving the way for innovative strategies to address muscle wasting and improve muscle health.

Sleep-Disordered Breathing and Chronic Respiratory Infections: A Narrative Review in Adult and Pediatric Population

Sleep-disordered breathing (SDB) comprises different diseases characterized by abnormal respiratory patterns during sleep including obstructive sleep apnea. SDB prevalence and impact in patients with chronic respiratory infections have been only marginally studied. The purpose of this narrative review is to report the prevalence and impact of SDB in chronic respiratory infections, including cystic fibrosis (CF), bronchiectasis and mycobacterial infections, and explore the possible pathophysiological mechanisms. Common pathophysiological mechanisms, underlying SDB onset in all chronic respiratory infections, include inflammation, which plays a central role, chronic nocturnal cough and pain, excessive production of mucous plugs, presence of obstructive and/or restrictive ventilatory impairment, upper airways involvement, and comorbidities, such as alteration of nutritional status. SDB may affect about 50% of patients with bronchiectasis. The severity of the disease, e.g., patients colonized with P. aeruginosa and frequent exacerbators, as well as comorbidities, such as chronic obstructive pulmonary disease and primary ciliary dyskinesia, may impact SDB onset. SDB may also frequently complicate the clinical course of both children and adults with CF, impacting the quality of life and disease prognosis, suggesting that their routine assessment should be incorporated into the clinical evaluation of patients from the first stages of the disease regardless of suggestive symptoms, in order to avoid late diagnosis. Finally, although the prevalence of SDB in patients with mycobacterial infections is uncertain, extrapulmonary manifestations, particularly nasopharyngeal locations, and concomitant symptoms, such as body pain and depression, may act as atypical predisposing factors for their development.

Sleep Apnea and Incident Unprovoked Venous Thromboembolism: Data from the Pays de la Loire Sleep Cohort

BACKGROUND

 Previous studies have reported inconsistent findings regarding the association between obstructive sleep apnea (OSA) and incident venous thromboembolism (VTE). More specifically, the association between OSA and unprovoked VTE was barely evaluated. We aimed to evaluate whether apnea hypopnea index (AHI) and nocturnal hypoxemia markers were associated with unprovoked VTE incidence in patients investigated for OSA.

STUDY DESIGN AND METHODS

 Data from the Pays de la Loire Sleep Cohort were linked to the French health administrative data to identify incident unprovoked VTE in patients suspected for OSA and no previous VTE disease. Cox proportional hazards models were used to evaluate the association of unprovoked VTE incidence with AHI and nocturnal hypoxemia markers including the time spent under 90% of saturation (T90), oxygen desaturation index, and hypoxic burden (HB), a more specific marker of respiratory events related to hypoxia. The impact of continuous positive airway pressure (CPAP) was evaluated in the subgroup of patients who were proposed the treatment.

RESULTS

 After a median [interquartile range] follow-up of 6.3 [4.3-9.0] years, 104 of 7,355 patients developed unprovoked VTE, for an incidence rate of 10.8 per 1,000 patient-years. In a univariate analysis, T90 and HB predicted incident VTE. In the fully adjusted model, T90 was the only independent predictor (hazard ratio: 1.06; 95% confidence interval: [1.01-1.02]; p = 0.02). The CPAP treatment has no significant impact on VTE incidence.

CONCLUSION

 Patients with more severe nocturnal hypoxia are more likely to have incident unprovoked VTE.

Association Between the Severity of Obstructive Sleep Apnea and the Risk Stratification of Acute Pulmonary Embolism

Obstructive sleep apnea (OSA) has been associated with the initiation and progression of cardiovascular disease. This study aimed to explore the relationship between the severity of OSA and the risk stratification of acute pulmonary embolism (PE). In this single-center cohort study, patients diagnosed with PE were evaluated for OSA via polygraphy monitoring. The simplified PE severity index (sPESI) and the number of patients requiring systemic thrombolysis were used to determine the severity of the disease. Echocardiography was performed on all participants. All patients were divided into 2 groups (OSA group and non-OSA group), and the patients in OSA group were then divided into 3 groups based on the severity of OSA. Patients with severe OSA had a significantly higher number of patients with sPESI ≥ 1 (P = .005). A higher proportion of patients with severe OSA require systemic thrombolysis (P = .010). Patients with apnea-hypopnea index (AHI) > 30/h had a much higher fibrinogen (P = .004) and D-dimer (P = .040) level than those in the non-OSA group. The levels of creatinine were significantly higher in patients with OSA (P = .040). Echocardiography showed a significant difference in left ventricular ejection fraction (LVEF) between patients in non-OSA and severe OSA groups (P = .035). And brain natriuretic peptide (BNP) also exhibited a progressive worsening related to the deepest desaturation and oxygen desaturation index. OSA, especially with AHI > 30/h, is correlated with the severity and prognosis of acute PE. This might be attributed to the prothrombotic effect, renal impairment, and cardiac dysfunction in patients with severe OSA.

Impact of high altitude on the incidence of postoperative venous thromboembolism and its genetic susceptibility: A meta-analysis and systematic review

BACKGROUND

The effect of high-altitude (HA) on venous thromboembolism (VTE) and its mechanism remains ambiguous. To clarify this, we aimed to conduct a meta-analysis and systematic review to evaluate the incidence of VTE at HA and comparatively low altitude (LA) and figure out the intrinsic risk factors such as susceptibility genes of patients with VTE at HA.

METHODS

We selected studies that explored the risk factors for HA and VTE by searching PubMed, Embase, and Web of Science to analyze the impact of HA on VTE. All relevant studies before August 2021 were screened using the terms ([high altitude] OR [plateau] OR [mountain]) AND ([venous thromboembolism] OR [deep vein thrombosis] OR [pulmonary embolism]). Latest studies on the gene of HA-VTE patients were also summarized and analyzed.

RESULTS

Fifteen studies were eventually assessed, and the overall numbers of subjects with and without VTE were 1475 and 286,926 respectively. The overall incidence of VTE, deep vein thrombosis (DVT) and pulmonary embolism (PE) in the HA group was significantly higher than that in the LA group (P < 0.01). The overall incidence of VTE, DVT and PE in the HA group was significantly higher than that in the LA group at 30 days post operation (P < 0.05, P < 0.05 and P < 0.01, respectively). At 90 days post operation, incidence of VTE and PE in the HA group was higher than that in the LA group (P < 0.01and P < 0.01, respectively), but there was no difference in the incidence of DVT (P = 0.07). Regarding endogenous factors, the analysis of genes in patients with HA-VTE revealed numerous targeted genes such as ANG, ACE, lncRNA-LINC00 659/UXT-AS1 and GP4.

CONCLUSIONS

We observed a significant association between HA and the overall incidence of VTE and that at 30/90 days post operation, indicating that HA may be a risk factor for VTE.

Effects of intermittent hypoxia with thrombin in an in vitro model of human brain endothelial cells and their impact on PAR-1/PAR-3 cleavage

Patients with obstructive sleep apnea/hypopnea (OSA) are at high risk of cerebrovascular diseases leading to cognitive impairment. The oxidative stress generated by intermittent hypoxia (IH) could lead to an increase in blood-brain barrier (BBB) permeability, an essential interface for the protection of the brain. Moreover, in patients with OSA, blood coagulation could be increased leading to cardiovascular complications. Thrombin is a factor found increased in these populations that exerts various cellular effects through activation of protease activated receptors (PARs). Thus, we have evaluated in an in vitro BBB model the association of IH with thrombin at two concentrations. We measured the apparent BBB permeability, expression of tight junctions, ROS production, HIF-1α expression, and cleavage of PAR-1/PAR-3. Pre-treatment with dabigatran was performed. IH and higher thrombin concentrations altered BBB permeability: high levels of HIF-1α expression, ROS and PAR-1 activation compared to PAR-3 in such conditions. Conversely, lower concentration of thrombin associated with IH appear to have a protective effect on BBB with a significant cleavage of PAR-3. Dabigatran reversed the deleterious effect of thrombin at high concentrations but also suppressed the beneficial effect of low dose thrombin. Therefore, thrombin and PARs represent novel attractive targets to prevent BBB opening in OSA.

PAI-1: A Major Player in the Vascular Dysfunction in Obstructive Sleep Apnea?

Obstructive sleep apnea is a chronic and prevalent condition that is associated with endothelial dysfunction, atherosclerosis, and imposes excess overall cardiovascular risk and mortality. Despite its high prevalence and the susceptibility of CVD patients to OSA-mediated stressors, OSA is still under-recognized and untreated in cardiovascular practice. Moreover, conventional OSA treatments have yielded either controversial or disappointing results in terms of protection against CVD, prompting the need for the identification of additional mechanisms and associated adjuvant therapies. Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of tissue-type plasminogen activator (tPA) and urinary-type plasminogen activator (uPA), is a key regulator of fibrinolysis and cell migration. Indeed, elevated PAI-1 expression is associated with major cardiovascular adverse events that have been attributed to its antifibrinolytic activity. However, extensive evidence indicates that PAI-1 can induce endothelial dysfunction and atherosclerosis through complex interactions within the vasculature in an antifibrinolytic-independent matter. Elevated PAI-1 levels have been reported in OSA patients. However, the impact of PAI-1 on OSA-induced CVD has not been addressed to date. Here, we provide a comprehensive review on the mechanisms by which OSA and its most detrimental perturbation, intermittent hypoxia (IH), can enhance the transcription of PAI-1. We also propose causal pathways by which PAI-1 can promote atherosclerosis in OSA, thereby identifying PAI-1 as a potential therapeutic target in OSA-induced CVD.

OSA and Chronic Respiratory Disease: Mechanisms and Epidemiology

Obstructive sleep apnea (OSA) is a highly prevalent disorder that has profound implications on the outcomes of patients with chronic lung disease. The hallmark of OSA is a collapse of the oropharynx resulting in a transient reduction in airflow, large intrathoracic pressure swings, and intermittent hypoxia and hypercapnia. The subsequent cytokine-mediated inflammatory cascade, coupled with tractional lung injury, damages the lungs and may worsen several conditions, including chronic obstructive pulmonary disease, asthma, interstitial lung disease, and pulmonary hypertension. Further complicating this is the sleep fragmentation and deterioration of sleep quality that occurs because of OSA, which can compound the fatigue and physical exhaustion often experienced by patients due to their chronic lung disease. For patients with many pulmonary disorders, the available evidence suggests that the prompt recognition and treatment of sleep-disordered breathing improves their quality of life and may also alter the course of their illness. However, more robust studies are needed to truly understand this relationship and the impacts of confounding comorbidities such as obesity and gastroesophageal reflux disease. Clinicians taking care of patients with chronic pulmonary disease should screen and treat patients for OSA, given the complex bidirectional relationship OSA has with chronic lung disease.

Obstructive Sleep Apnea as a Risk Factor for Venous Thromboembolism: A Systematic Review

Obstructive sleep apnea (OSA), is a prevalent condition characterized by repeated episodes of pharyngeal airway obstruction resulting in hypopnea and apnea episodes during sleep leading to nightly awakenings. OSA is a major contributor to the healthcare burden worldwide due to its high cardiovascular morbidity and mortality. There is growing evidence to support a pathophysiological link between OSA and venous thromboembolism (VTE). The pro-inflammatory state along with intermittent hypoxia that is invoked in OSA is associated with blood hypercoagulability, venous stasis, and endothelial dysfunction leading to deep vein thrombosis (DVT) and pulmonary embolism (PE). In this systematic review, we aim to analyze and assess the available literature on OSA and VTE (or DVT/PE) to determine whether OSA is an independent risk factor for VTE.

Association between obstructive sleep apnea and venous thromboembolism recurrence: results from a French cohort

Background

Growing evidence suggests the relationship between obstructive sleep apnea (OSA) and venous thromboembolism (VTE). Few studies focused on VTE recurrence risk associated with OSA after anticoagulation cessation.

Methods

In a prospective cohort study, patients with documented VTE, were followed for an indefinite length of time and VTE recurrence were documented and adjudicated. The primary outcome was recurrent VTE after anticoagulation discontinuation. Secondary outcomes included all-cause mortality and the clinical presentation of VTE. Univariable and multivariable analyses were performed to identify risk factors for recurrence and mortality.

Results

Among the 2109 patients with documented VTE included, 74 patients had moderate to severe OSA diagnosis confirmed by home sleep test or polysomnography. During a median follow-up of 4.8 (interquartile range 2.5–8.0) years recurrent VTE occurred in 252 patients (9 with OSA and 243 without OSA). The recurrence risk in the univariable and multivariable analysis was not increased in patients with OSA, regardless of the time of diagnosis (before or after index VTE or pooled). VTE phenotype was significantly more often PE with or without associated deep vein thrombosis in the first event and recurrence for OSA patients compared to non-OSA patients. The risk of death was not increased in the OSA population compared to non-OSA patients in multivariable analysis.

Conclusions

In patients with OSA and VTE, the risk of all-cause mortality and VTE recurrence after anticoagulation discontinuation was not increased compared to non-OSA patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00358-8.

Incidence of venous thromboembolism in patients with obstructive sleep apnea: a cohort study

BACKGROUND

Previous studies suggesting that obstructive sleep apnea (OSA) may be an independent risk factor for venous thromboembolism (VTE) have been limited by reliance on administrative data and lack of adjustment for clinical variables, including obesity.

RESEARCH QUESTION

Does OSA confer an independent risk of incident VTE among a large clinical cohort referred for sleep disordered breathing evaluation?

STUDY DESIGN AND METHODS

We analyzed the clinical outcomes of 31,309 patients undergoing overnight polysomnography within a large hospital system. We evaluated the association of OSA severity with incident VTE using Cox proportional hazards modeling accounting for age, sex, body mass index (BMI), and common comorbid conditions.

RESULTS

Patients were of mean age 50.4 years and 50.1% female. There were 1,791 VTE events identified over a mean follow-up of 5.3 years. In age and sex-adjusted analyses, each 10 event/hr increase in the apnea hypopnea index (AHI) was associated with a 4% increase in incident VTE risk (hazard ratio [HR] 1.04, 95% confidence interval [CI] 1.02-1.05). After adjusting for BMI, this association disappeared (HR 1.01, 95% CI 0.99-1.03). In contrast, nocturnal hypoxemia had an independent association with incident VTE. Patients with >50% sleep time spent with oxyhemoglobin saturation <90% are at 48% increased VTE risk compared to those without nocturnal hypoxemia (HR 1.48, 95% CI 1.16-1.69).

INTERPRETATION

In this large cohort, we found that patients with more severe OSA as measured by the AHI are more likely to have incident VTE. Adjusted analyses suggest that this association is explained due to confounding by obesity. However, severe nocturnal hypoxemia may be a mechanism by which OSA heightens VTE risk.

Supervised Versus Unsupervised Pulmonary Rehabilitation in Patients with Pulmonary Embolism: A Valuable Alternative in COVID Era

The aim of our study was to assess the effect of 8 weeks of pulmonary rehabilitation (PR) in patients with pulmonary embolism (PE) during unsupervised PR (unSPR_group) versus supervised PR (SPR_group) on cardiopulmonary exercise testing (CPET) parameters, sleep quality, quality of life and cardiac biomarkers (NT-pro-BNP). Fourteen patients with PE (unSPR_group, n = 7, vs. SPR_group, n = 7) were included in our study (age, 50.7 ± 15.1 years; BMI, 30.0 ± 3.3 kg/m²). We recorded anthropometric characteristics and questionnaires (Quality of life (SF-36) and Pittsburg sleep quality index (PSQI)), we performed blood sampling for NT-pro-BNP measurement and underwent CPET until exhausting before and after the PR program. All patients were subjected to transthoracic echocardiography prior to PR. The SPR_group differed in mean arterial pressure at rest before and after the PR program (87.6 ± 3.3 vs. 95.0 ± 5.5, respectively, p = 0.010). Patients showed increased levels of leg fatigue (rated after CPET) before and after PR (p = 0.043 for SPR_group, p = 0.047 for unSPR_group) while the two groups differed between each other (p = 0.006 for post PR score). Both groups showed increased levels in SF-36 scores (general health; p = 0.032 for SPR_group, p = 0.010 for unSPR_group; physical health; p = 0.009 for SPR_group, p = 0.022 for unSPR_group) and reduced levels in PSQI (cannot get to sleep within 30-min; p = 0.046 for SPR_group, p = 0.007 for unSPR_group; keep up enough enthusiasm to get things done; p = 0.005 for SPR_group, p = 0.010 for unSPR_group) following the PR program. The ΝT-pro-BNP was not significantly different before and after PR or between groups. PR may present a safe intervention in patients with PE. The PR results are similar in SPR_group and unSPR_group.

Neuropeptide Y: An Update on the Mechanism Underlying Chronic Intermittent Hypoxia-Induced Endothelial Dysfunction

Endothelial dysfunction (ED) is a core pathophysiological process. The abnormal response of vascular endothelial (VE) cells to risk factors can lead to systemic consequences. ED caused by intermittent hypoxia (IH) has also been recognized. Neuropeptide Y (NPY) is an important peripheral neurotransmitter that binds to different receptors on endothelial cells, thereby causing ED. Additionally, hypoxia can induce the release of peripheral NPY; however, the involvement of NPY and its receptor in IH-induced ED has not been determined. This review explains the definition of chronic IH and VE function, including the relationship between ED and chronic IH-related vascular diseases. The results showed that that the effect of IH on VE injury is mediated by the VE-barrier structure and endothelial cell dysfunction. These findings offer new ideas for the prevention and treatment of obstructive sleep apnea syndrome and its complications.

Obstructive Sleep Apnea, Hypercoagulability, and the Blood-Brain Barrier

Obstructive sleep apnea (OSA) is characterized by repeated episodes of intermittent hypoxia (IH) and is recognized as an independent risk factor for vascular diseases that are mediated by a multitude of mechanistic pathophysiological cascades including procoagulant factors. The pro-coagulant state contributes to the development of blood clots and to the increase in the permeability of the blood-brain barrier (BBB). Such alteration of BBB may alter brain function and increase the risk of neurodegenerative diseases. We aim to provide a narrative review of the relationship between the hypercoagulable state, observed in OSA and characterized by increased coagulation factor activity, as well as platelet activation, and the underlying neural dysfunction, as related to disruption of the BBB. We aim to provide a critical overview of the existing evidence about the effect of OSA on the coagulation balance (characterized by increased coagulation factor activity and platelet activation) as on the BBB. Then, we will present the emerging data on the effect of BBB disruption on the risk of underlying neural dysfunction. Finally, we will discuss the potential of OSA therapy on the coagulation balance and the improvement of BBB.

Right-to-left Ventricular Diameter Ratio At Computed Tomographic Pulmonary Angiography in Patients with Acute Pulmonary Embolism and Obstructive Sleep Apnea

Purpose:

Right ventricular (RV) dysfunction in acute pulmonary embolism (PE) is a critical determinant of outcome. Obstructive sleep apnea (OSA) is a common comorbidity of PE and might also affect RV function. Therefore, we sought to investigate RV dysfunction in PE patients in proportion to the severity of OSA by evaluating the right-to-left ventricular (RV/LV) diameter ratio on computed tomographic pulmonary angiography (CTPA).

Materials and Methods:

197 PE patients were evaluated for sleep-disordered breathing by portable monitoring and nocturnal polysomnography. RV dilatation was defined as an RV/LV diameter ratio of ⩾ 1.0.

Results:

RV dilatation was significantly more frequent in OSA patients compared to study participants without OSA (66.4% vs 49.1%, P = .036). Elevated troponin I values, indicating myocardial injury due to acute, PE-related RV strain, were significantly more frequent in OSA patients with an apnea-hypopnea index (AHI) ⩾ 15/h compared to those with an AHI < 15/h (62.1% vs 45.8%, P = .035). However, RV dysfunction documented by the RV/LV diameter ratio on CTPA was not significantly associated with the severity of OSA in multivariable regression analysis.

Conclusion:

Patients with moderate or severe OSA might compensate acute, PE-related RV strain better, as they are adapted to repetitive right heart pressure overloads during sleep.

The role of obstructive sleep apnea on the prognosis of pulmonary embolism: a systemic review and meta-analysis

PURPOSE

The relationship between obstructive sleep apnea (OSA) and pulmonary embolism (PE) has been reported by some studies but the underlying mechanism remains unclear. We aimed to systematically assess the role of OSA on the disease prognosis of PE.

METHODS

We searched for studies on the relationship of OSA and the prognosis of PE published up to February 2020 among PubMed, Web of Science, EMBASE, and Cochrane Library databases. Two independent reviewers conducted the process of study search and screening, quality assessment, and data extraction. Meta-analysis was carried out using RevMan 5.3.

RESULTS

A total of 9 articles were included, and the funnel plots suggested no evidence of publication bias among studies. The results showed that compared to PE patients without OSA, the PE patients with moderate-severe OSA were more likely to be high-risk type (OR = 1.96, 95% CI [1.14, 3.34]) and with higher index of disease severity (sPESI: OR = 2.29, 95% CI [1.50, 3.47]; PAOI%: MD = 13.52, 95% CI [7.2, 19.83]). The prevalence of recurrent PE was higher in PE patients with OSA than those without OSA (RR = 3.87, 95% CI [1.65, 9.07]). However, there was no significant difference in right ventricle to left ventricle short-axis diameter (MD = 0.08, 95% CI [- 0.06, 0.21]), length of hospital stay (MD = 1.03, 95% CI [- 1.11, 3.17]), or prevalence of deep vein thrombosis (OR = 0.87, 95% CI [0.48, 1.57]). Sensitivity and subgroup analysis showed that the pooled outcomes were stable.

CONCLUSION

OSA, especially moderate-severe OSA, was a risk factor for high-risk PE and recurrent PE. However, the current evidence showed that the length of hospital stay is not influenced by OSA.

Effects of hypoxia environment on osteonecrosis of the femoral head in Sprague-Dawley rats

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) is a disease in which the blood supply of the femoral head is interrupted or damaged, resulting in joint dysfunction. Hypoxic environments increase the expression of EPO, VEGF, and HIF causes vascular proliferation and increases the blood supply. It also causes the organism to be in a state of hypercoagulability and increases thrombosis. Therefore, the purpose of this study was to explore the occurrence of ONFH after the use of glucocorticoids (GCs) under conditions of hypoxia tolerance for a long time.

MATERIALS AND METHODS

Sprague-Dawley rats were fed in a hypobaric hypoxic chamber at an altitude of 4000 m, the whole blood viscosity, and plasma viscosity were determined to analyze the blood flow and hemagglutination. Western blotting, polymerase chain reaction, and immunohistochemistry were used to detect EPO, VEGF, CD31, and osteogenesis related proteins. Femoral head angiography was used to examine the local blood supply and micro-CT scanning was used to detect the structure of the bone trabecula.

RESULTS

Under hypoxic environments, the expression of EPO and VEGF increased, which increased the local blood supply of the femoral head, but due to more severe thrombosis, the local blood supply of the femoral head decreased.

CONCLUSIONS

Hypoxic environments can aggravate ONFH in SD rats; this aggravation may be related to the hypercoagulable state of the blood. We suggest that long-term hypoxia should be regarded as one of the risk factors of ONFH and we need to conduct a more extensive epidemiological investigation on the occurrence of ONFH in hypoxic populations.

Circulating Soluble Urokinase-Type Plasminogen Activator Receptor in Obstructive Sleep Apnoea

Background and Objectives: Obstructive sleep apnoea (OSA) is associated with heightened systemic inflammation and a hypercoagulation state. Soluble urokinase-type plasminogen activator receptor (suPAR) plays a role in fibrinolysis and systemic inflammation. However, suPAR has not been investigated in OSA. Materials and Methods: A total of 53 patients with OSA and 15 control volunteers participated in the study. Medical history was taken and in-hospital sleep studies were performed. Plasma suPAR levels were determined by ELISA. Results: There was no difference in plasma suPAR values between patients with OSA (2.198 ± 0.675 ng/mL) and control subjects (2.088 ± 0.976 ng/mL, p = 0.62). Neither was there any difference when patients with OSA were divided into mild (2.134 ± 0.799 ng/mL), moderate (2.274 ± 0.597 ng/mL) and severe groups (2.128 ± 0.744 ng/mL, p = 0.84). There was no significant correlation between plasma suPAR and indices of OSA severity, blood results or comorbidities, such as hypertension, diabetes, dyslipidaemia or cardiovascular disease. Plasma suPAR levels were higher in women when all subjects were analysed together (2.487 ± 0.683 vs. 1.895 ± 0.692 ng/mL, p < 0.01), and also separately in controls (2.539 ± 0.956 vs. 1.411 ± 0.534 ng/mL, p = 0.02) and patients (2.467 ± 0.568 vs. 1.991 ± 0.686 ng/mL, p < 0.01). Conclusions: Our results suggest that suPAR does not play a significant role in the pathophysiology of OSA. The significant gender difference needs to be considered when conducting studies on circulating suPAR.

Blood Oxygen Accumulation Distribution Area Index Is Associated With Erectile Dysfunction in Patients With Sleep Apnea-Results From a Cross-sectional Study

Introduction

Obstructive sleep apnea (OSA) has been linked with erectile dysfunction (ED), but the relatively independent polysomnography (PSG) outcomes of apnea and nocturnal hypoxia may not effectively assess the physiological impairment of OSA well.

Aim

To propose a new calculation method, the blood oxygen accumulation distribution area index (BOADAI), for evaluating the association between OSA and ED.

Methods

In this study, 502 male participants with suspected OSA were enrolled. Clinical questionnaire, physical measurements, and PSG outcomes were obtained by 2 respiratory physicians. ED was assessed by a urologist using the International Index of Erectile Function-5 (IIEF-5). Whole pulse oxygen saturation curves during the sleep time were compressed into a fixed scale image, and the distribution area of oxygen saturation curves was outlined. We then calculated the value of the outlined area and normalized it by total sleep time. The least absolute shrinkage and selection operator logistic regression model was used for selecting the optimal variable associated with ED and model construction. The clinical net benefit of the BOADAI and its related modules was estimated and compared by decision curve analysis.

Main Outcome Measure

ED and OSA were assessed using the IIEF-5, clinical questionnaire, physical measurements, and PSG outcomes.

Results

The frequency of ED in patients with OSA was significantly greater than that in the no-OSA group. Meanwhile, the new BOADAI was negatively correlated with the IIEF-5 score (r = −0.2525, P = .0000). Moreover, the least absolute shrinkage and selection operator method retained BOADAI but not the other PSG parameters such as respiratory disorder index and lowest SaO2. Finally, logistic regression analysis revealed that older age, lips with cyanochroia, systemic hypertension, and BOADAI were independently associated with ED, and decision curve analysis indicated the clinical usefulness of the BOADAI module.

Conclusion

This study revealed novel evidence that OSA is a risk factor for ED. Meanwhile, the BOADAI could act as a potential clinical characteristic to evaluate ED in patients with OSA and to provide clinical treatment recommendations.

Zheng W, Chen X, Huang J, et al. Blood Oxygen Accumulation Distribution Area Index Is Associated With Erectile Dysfunction in Patients With Sleep Apnea—Results From a Cross-sectional Study. Sex Med 2019; 8:36–44.

Long-term outcomes in patients with acute pulmonary embolism after in-hospital treatment: study protocol of the prospective Lungenembolie Augsburg Studie (LEA study)

INTRODUCTION

Acute pulmonary embolism (PE) is a frequent life-threatening event and an important cause of hospitalisation, morbidity and mortality worldwide. Limited information on the long-term course of PE patients is available so far. The Lungenembolie Augsburg study will provide a view on the predisposing and PE-provoking factors, diagnostic procedures and short as well as long-term treatment options. Especially, the data on the long-term course of the disease-in combination with omics data obtained in biospecimens-will generate new knowledge regarding triggers, disease progression, treatment, long-term sequelae, prognosis and prevention of disease recurrence.

METHODS AND ANALYSIS

In this prospective study, we will include about 1000 patients admitted to the university hospital of Augsburg, aged 18 years and older with a confirmed diagnosis of acute PE. At baseline, demographic information, symptoms on presentation, delay in diagnosis, predisposing and PE-provoking factors, comorbidity, quality of life, symptoms of anxiety and depression, information on invasive and non-invasive treatment procedures, complications and laboratory parameters will be collected. During the hospital stay, 30 mL blood will be collected from the patients, processed, aliquoted and frozen at -80°C. In a subgroup of patients, an eight-channel polygraphy will be carried out to assess sleep-disordered breathing. All study participants will be followed up for 60 months via postal questionnaires or telephone interviews after hospital discharge. Long-term survival, bleeding complications and PE recurrence during the follow-up are the primary study outcomes. To identify risk factors and determinants associated with these outcomes, confounder-adjusted Cox-regressions will be used for modelling and to estimate relative risks. Effect modification by age and sex will be examined.

ETHICS AND DISSEMINATION

The study protocol was approved by the Ethics Committee of the Ludwig-Maximilians-Universität München (Date of approval: 1 August 2017, Reference number: 17-378). Study results will be presented at national and international conferences and published in peer-reviewed scientific journals.

Prevalence of obstructive sleep apnea syndrome in patients with lymphedema referred for complete decongestive therapy

OBJECTIVE

Obstructive sleep apnea (OSA) syndrome is one of the most frequent chronic diseases in the general population. The nocturnal rostral fluid shift is accepted as a key mechanism in OSA pathogenesis in medical conditions associated with fluid overload. The main objective of this study was to assess the prevalence of OSA in patients with lymphedema.

METHODS

A prospective study was conducted in patients with lymphedema hospitalized for complete decongestive therapy between December 2016 and November 2017. A nocturnal respiratory polygraphy, an Epworth sleepiness scale, and lymphedema volume measurements were performed on the first day of decongestive therapy. OSA was diagnosed in patients with an apnea-hypopnea index of five or more events per hour and patients who had been previously diagnosed with OSA and treated by continuous positive airway pressure were identified.

RESULTS

Forty-three patients completed the study. The prevalence of OSA was 74% and was higher for patients with lymphedema of the lower limbs (85%) vs upper limbs (56%). OSA severity was correlated with a marker of lower limb lymphedema severity (P = .012). The body mass index was higher than in patients with OSA than patients without OSA (median, 31.0 kg/m² [25th; 75th percentiles, 25.3; 37.0 kg/m²] vs median, 24.2 kg/m² [25th; 75th percentiles, 22.7; 26.7 kg/m²]; P < .01). Hypertension was prevalent in 47% of patients with OSA vs 18% in patients without OSA.

CONCLUSIONS

Patients with lymphedema presenting for complete decongestive therapy present a high prevalence rate of OSA, particularly in those with lower limb lymphedema. OSA severity was correlated with a marker of lower limb lymphedema severity. These results suggest that overweight and obese patients with lymphedema should be screened systematically for OSA.

Obstructive sleep apnea is associated with pulmonary artery thrombus load, disease severity, and survival in acute pulmonary embolism

INTRODUCTION

Obstructive sleep apnea (OSA) may have prothrombotic effects.

OBJECTIVE

To investigate the effect of OSA on disease severity, pulmonary artery thrombus load, and prognosis in patients with acute pulmonary embolism (PE).

METHODS

In 101 PE patients, disease severity was determined by the simplified PE severity index (sPESI) score, pulmonary artery thrombus load was quantified by the pulmonary artery obstruction index (PAOI), and sleep-disordered breathing was evaluated by nocturnal polygraphy.

RESULTS

Obstructive sleep apnea patients with an apnea-hypopnea index (AHI) ≥ 15/h cohort were significantly older (p < 0.001) and had significantly lower oxygen saturations (p = 0.008) when acute PE was diagnosed. The sPESI scores (p < 0.001), the PAOI (p = 0.005) and the N-terminal pro-brain-type natriuretic peptide (NT-proBNP) values (p = 0.009), were significantly higher in the AHI ≥ 15/h subgroup. In a multivariate regression analysis, the AHI remains a significant predictor for sPESI scores ≥ 1 (p = 0.003), increased NT-proBNP levels (p = 0.047), and elevated PAOI (p = 0.032). During the median follow-up time of 53 (interquartile range 38-70) months, all-cause and cardiovascular-related mortality was significantly higher in the AHI ≥ 15/h cohort (p = 0.004 and p = 0.015, respectively).

CONCLUSIONS

Obstructive sleep apnea is associated with pulmonary artery thrombus load, disease severity, and survival in acute PE possibly due to its prothrombotic effects.