Continuous positive airway pressure treatment improves pulmonary hemodynamics in patients with obstructive sleep apnea

Admission for COPD Exacerbation Is Associated with the Clinical Diagnosis of Pulmonary Hypertension: Results from a Retrospective Longitudinal Study of a Veteran Population

Patients with chronic obstructive pulmonary disease and pulmonary hypertension (PH-COPD) have an increased risk of hospitalizations and death compared to COPD alone. Identifying PH in COPD is challenging because performing right heart catheterization, the gold standard for PH diagnosis, is invasive and not routinely performed. Clinical characterization of COPD patients at risk who are progressing toward PH will aid therapeutic development at earlier stages of progressively fatal PH-COPD. We studied the records of 5,45,086 patients in a large Veterans Affairs healthcare network (2000-2012) with a primary discharge diagnosis of COPD based on encounters' ICD-9 codes and further stratified into those who received an additional ICD-9 code for a PH diagnosis. Patients with PH-COPD were assigned to one of the four subgroups: those with (a) no history of exacerbation or hospital admissions, (b) history of exacerbations but no hospital admissions, (c) hospital admissions unrelated to COPD and (d) history of COPD exacerbation-related hospital admissions. We also examined the COPD and COPD-PH cohorts for associated comorbidities such as cardiac disease and the presence of obstructive sleep apnea (OSA). A regression analysis revealed that patients with COPD exacerbation-related hospital admissions had 7 × higher risk of having a concomitant clinical diagnosis of PH compared to non-hospitalized patients. COPD-PH patients had higher rates of cardiac comorbidities (89% vs. 66%) and OSA (34% vs. 16%) compared to COPD alone. We conclude that COPD patients hospitalized for COPD exacerbations are at a higher risk for developing PH, and hospitalized COPD patients with cardiac comorbidities and/or OSA should be screened as at-risk population for developing PH.

Obesity, Cardiovascular Disease and Sleep Disorders: Insights into the Rising Epidemic

Cardiovascular disease (CVD) is the main cause of death among adult men and women in the USA and impacts millions around the globe. Traditional risk factors for CVD include obesity, diabetes, hypertension and dyslipidemia. The modern-day epidemic of obesity not only increased the rate of CVD but also ushered in an additional CVD risk factor to be added to the list; that is obstructive sleep apnea (OSA). In this review, we discuss the growing epidemic of obesity and OSA, highlighting the common pathogenic hypotheses linking these risk factors to CVD. We will also highlight the therapeutic rationale of OSA as a way to reduce CVD risk.

Precapillary Pulmonary Hypertension and Sleep-Disordered Breathing: Is There a Link?

Among patients with sleep apnea the reported prevalence of precapillary pulmonary hypertension (PH) has varied largely, depending on patient selection, disease definition, and associated conditions, in particular chronic pulmonary disease. However, in the absence of comorbidities, PH seems to be rare in patients with sleep apnea. Conversely, sleep-related breathing disorders have been commonly found in patients with PH and they have been associated with an impaired quality of life. Since sleep-related breathing disorders may affect the pulmonary circulation and vice versa, patients with sleep-related breathing disorders should be evaluated for risk factors, symptoms and clinical signs of PH and right ventricular heart failure and patients with PH should be evaluated for sleep apnea. Therapeutic options for patients with sleep apnea and PH may include supplemental oxygen, drugs and positive pressure ventilation. Both nocturnal oxygen administration and acetazolamide have been shown to improve sleep apnea in patients with PH. In addition, oxygen therapy also improved exercise performance. Further studies are needed to corroborate the efficacy of these and other treatments.

Pulmonary Hypertension Due to Common Respiratory Conditions: Classification, Evaluation and Management Strategies

Pulmonary hypertension (PH) due to chronic respiratory disease and/or hypoxia is classified as World Health Organization (WHO) Group III pulmonary hypertension. The patients most commonly encountered in clinical practice with group III PH include those with chronic obstructive lung disease (COPD), diffuse parenchymal lung disease, and sleep-disordered breathing. The purpose of this review is to outline the variable clinical significance of pulmonary hypertension in the most common pulmonary disease states and how a clinician may approach the management of these patients.

Sleep Disordered Breathing: Hypertension and Cardiac Structure and Function

Obstructive sleep apnea (OSA) is a common form of sleep disordered breathing and has a relatively high prevalence in the general population. The frequency and severity of OSA is associated with age, male sex, and obesity, and OSA has been linked to cardiovascular complications and death. Importantly, OSA has a strong association with both prevalent and incidental hypertension and has a particularly high prevalence in patients with resistant hypertension. In these patients, CPAP and other OSA-directed treatments have been proposed as therapy to help control blood pressure (BP), especially in patients who have not attained optimal BP control despite maximum pharmacological therapy. OSA has also been associated with alterations in cardiac structure and function, although most studies are small and highly limited in study design. Existing data suggest an association between OSA greater left ventricle (LV) mass and hypertrophy that appears independent of confounders including hypertension and obesity. Although less clear and more controversial, OSA severity has been linked to LV systolic and diastolic function, pulmonary hypertension, and right ventricular hypertrophy. Further studies are needed to confirm the potential causal role of OSA in these observed associations with cardiac abnormalities.

Significance of obstructive sleep apnea in the patient with pulmonary hypertension

PURPOSE OF REVIEW

The purpose of this review was to evaluate the consequence of obstructive sleep apnea (OSA) in pulmonary hypertension by reviewing the current literature and understanding potential pathophysiological mechanisms.

RECENT FINDINGS

Small studies have suggested a high prevalence of comorbid OSA in those with known pulmonary hypertension. Pathophysiological mechanisms are highly suggestive of potential deleterious effect of OSA on pulmonary hemodynamics.

SUMMARY

Clearly, current research work on comorbid OSA and pulmonary hypertension is still in its infancy and the field is ripe for future investigation. The significance of OSA in this population has yet to be fully determined.

A pathway underlying the impact of CPAP adherence on intimate relationship with bed partner in men with obstructive sleep apnea

PURPOSE

Our aim was to determine the pathway underlying the effects of continuous positive airway pressure (CPAP) adherence on intimate relationship with bed partner in men with obstructive sleep apnea (OSA). We hypothesized that CPAP with good adherence affected the intimate relationship with bed partner directly and indirectly, and it was mediated through daytime sleepiness and activity level in men with OSA.

METHODS

Data were obtained from an education program for enhancing CPAP adherence. Men who were newly diagnosed of OSA and CPAP therapy naïve were recruited in a tertiary teaching hospital.

RESULTS

Self-reported quality of life [Functional Outcomes of Sleep Questionnaire], daytime sleepiness [Epworth Sleepiness Scale (ESS)], and negative emotion symptoms [depression, anxiety, stress scale] were assessed before and after CPAP treatment at 1-year assessment. Seventy-three men were included in the data analysis, with a mean ± SD age of 52 ± 10 years, body mass index of 29.0 ± 5.2 kg/m(2), ESS of 9.5 ± 5.6, and median [interquartile range(IR)] apnea and hypopnea index of 31 (21, 56) events/h. The median (IR) CPAP daily usage was 4.3(0, 6.1) h/day. From the path analysis, CPAP therapy was shown to improve intimate relationship directly (ß = 0.185) and indirectly (ß = 0.050) by reducing daytime sleepiness and increasing activity level. However, negative emotion symptoms were not the mediators between CPAP adherence and the intimate relationship.

CONCLUSIONS

CPAP therapy with good adherence is related directly and indirectly to a better intimate relationship with bed partner in men with OSA. It was possibly attributed to reduced daytime sleepiness and increased activity level.

The Sleep Apnea cardioVascular Endpoints (SAVE) Trial: Rationale, Ethics, Design, and Progress

ABSTRACT

The Sleep Apnea cardioVascular Endpoints (SAVE) study is an ongoing investigator-initiated and conducted, international, multicenter, open, blinded endpoint, randomized controlled trial that was designed to determine whether treatment of obstructive sleep apnea (OSA) with continuous positive airways pressure (CPAP) can reduce the risk of serious cardiovascular (CV) events in patients with established CV disease (clinical trial registration NCT00738179). The results of this study will have important implications for the provision of health care to patients with sleep apnea around the world. The SAVE study has brought together respiratory, sleep, CV and stroke clinicians-scientists in an interdisciplinary collaboration with industry and government sponsorship to conduct an ambitious clinical trial. Following its launch in Australia and China in late 2008, the recruitment network expanded across 89 sites that included New Zealand, India, Spain, USA, and Brazil for a total of 2,717 patients randomized by December 2013. These patients are being followed until December 2015 so that the average length of follow-up of the cohort will be over 4 y. This article describes the rationale for the SAVE study, considerations given to the design including how various cultural and ethical challenges were addressed, and progress in establishing and maintaining the recruitment network, patient follow-up, and adherence to CPAP and procedures. The assumptions underlying the original trial sample size calculation and why this was revised downward in 2012 are also discussed.

CLINICAL TRIALS REGISTRATION NUMBER

NCT00738179.

AUSTRALIA NEW ZEALAND CLINICAL TRIALS REGISTRY NUMBER

ACTRN12608000409370.

Pulmonary hypertension in obstructive sleep apnea: is it clinically significant? A critical analysis of the association and pathophysiology

The development of pulmonary hypertension is a poor prognostic sign in patients with obstructive sleep apnea (OSA) and affects both mortality and quality of life. Although pulmonary hypertension in OSA is traditionally viewed as a result of apneas and intermittent hypoxia during sleep, recent studies indicate that neither of these factors correlates very well with pulmonary artery pressure. Human data show that pulmonary hypertension in the setting of OSA is, in large part, due to left heart dysfunction with either preserved or diminished ejection fraction. Longstanding increased left heart filling pressures eventually lead to pulmonary venous hypertension. The combination of hypoxic pulmonary vasoconstriction and pulmonary venous hypertension with abnormal production of mediators will result in vascular cell proliferation and aberrant vascular remodeling leading to pulmonary hypertension. These changes are in many ways similar to those seen in other forms of pulmonary hypertension and suggest shared mechanisms. The majority of patients with OSA do not receive a diagnosis and are undertreated. Appreciating the high prevalence and understanding the mechanisms of pulmonary hypertension in OSA would lead to better recognition and management of the condition.

Idiopathic pulmonary fibrosis and sleep disorders: no longer strangers in the night

The prevalence of obstructive sleep apnoea (OSA) is continuously increasing in patients with idiopathic pulmonary fibrosis (IPF) and, for the first time, the recent IPF guidelines recognise OSA as an important associated comorbidity that can affect patient's survival. Thus, it becomes conceivable that clinicians should refer patients with newly diagnosed IPF to sleep centres for the diagnosis and treatment of OSA as well as for addressing issues regarding the reduced compliance of patients with continuous positive airway pressure therapy. The discovery of biomarkers common to both disorders may help early diagnosis, institution of the most appropriate treatment and follow-up of patients. Better understanding of epigenetic changes may provide useful information about pathogenesis and, possibly, development of new drugs for a dismal disease like IPF.

It is now believed that IPF and sleep disorders can coexist in the same patienthttp://ow.ly/LXPSL

Obstructive sleep apnea is associated with liver disease: a population-based cohort study

BACKGROUND

The association between obstructive sleep apnea (OSA) and the risk of liver disease is unclear. Moreover, population-based studies on the risk of liver disease among people with OSA have not yet been conducted. This study aimed to investigate the risk of subsequent development of liver disease among people with OSA.

METHODS

Using Taiwan National Health Insurance claims data, this study collected subjects from a cohort of 17,374 people with OSA who were diagnosed between 2000 and 2008. A control group of 69,496 people was selected from the same database and matched by age, gender, urbanization, income, and date of initial admission. All subjects were followed up until 2010. Liver disease incidence and risk were calculated.

RESULTS

The overall risk of liver disease among people with OSA was significantly higher than in the control group (aHR = 5.52, p <0.001). Non-alcoholic fatty liver disease, cirrhosis, and hepatitis C had significant aHRs of 5.29, 7.50, and 7.19 (all at p <0.001), respectively. In contrast, hepatitis B had the smallest aHR of 3.71.

CONCLUSIONS

The risk of liver disease was more than five times higher among people with OSA compared with the control group; this was particularly for cirrhosis and hepatitis C. Liver disease is thus a very important health issue among people with OSA.

OSA and pulmonary hypertension: time for a new look

OSA is a common yet underdiagnosed disorder encountered in everyday practice. The disease is a unique physiologic stressor that contributes to the development or progression of many other disorders, particularly cardiovascular conditions. The pulmonary circulation is specifically affected by the intermittent hypoxic apneas associated with OSA. The general consensus has been that OSA is associated with pulmonary hypertension (PH), but only in a minority of OSA patients and generally of a mild degree. Consequently, there has been no sense of urgency to screen for either condition when evaluating the other. In this review, we explore available evidence describing the interaction between OSA and PH and seek to better understand underlying pathophysiology. We describe certain groups of patients who have a particular preponderance of OSA and PH. Failure to recognize the mutual additive effects of these disorders can lead to suboptimal patient outcomes. Among patients with PH and OSA, CPAP, the mainstay treatment for OSA, may ameliorate pulmonary pressure elevations, but has not been studied adequately. Conversely, among patients with OSA, PH significantly limits functional capacity and potentially shortens survival; yet, there is no routine screening for PH in patients with OSA. We think it is time to study the interaction between OSA and PH more carefully to identify high-risk subgroups. These would be screened for the presence of combined disorders, facilitating earlier institution of therapy and improving outcomes.

An evidence-based approach to screening and diagnosis of pulmonary hypertension

Pulmonary hypertension (PH) continues to be a devastating disease, with a poor prognosis and high mortality rate if not treated early. Unfortunately, most patients are still diagnosed late in the course of the disease. Therefore, it is crucial to have a low threshold for suspecting PH and to refer patients early to specialized centres for diagnostic workup and management. In this article we focus on updated evidence-based screening and diagnosis in adults, based on the fifth World Symposium on Pulmonary Hypertension in 2013. The updated hemodynamic definition of PH includes a pulmonary vascular resistance > 3 Wood units. A new component to the hemodynamic definition of PH has been proposed in left heart disease, based on a diastolic pulmonary gradient (diastolic pulmonary arterial pressure - mean pulmonary artery wedge pressure), > 7 mm Hg. The term "borderline PH" for mean pulmonary artery pressures 21-24 mm Hg is discouraged, with emphasis on its significance for careful follow-up in high-risk patients, especially in systemic sclerosis. Annual pulmonary arterial hypertension (PAH) screening with a 2-step algorithm is recommended in asymptomatic systemic sclerosis patients. An updated simplified PH diagnostic algorithm approach is proposed. Genetic testing reveals mutations in bone morphogenic protein receptor type II in 70% of familial PAH, and is useful for screening asymptomatic family members. Important associated conditions that should be considered include thyroid disease, left heart disease, toxic causes, lung diseases (including pulmonary thromboembolism), hemolytic anemia, and human immunodeficiency virus infection. Biomarkers have been identified that correlate with PAH severity and mortality and are useful in follow-up.

Effect of CPAP treatment for obstructive sleep apnea hypopnea syndrome on lipid profile: a meta-regression analysis

STUDY OBJECTIVE

Patients with obstructive sleep apnea (OSA) frequently exhibit higher rates of dyslipidemia, a risk factor for cardiovascular and cerebrovascular disorders. Treatment for OSA by CPAP may improve cholesterol metabolism. This meta-regression analysis (MA) estimates the effect of CPAP treatment on dyslipidemia.

METHODS

PubMed and Cochrane libraries were searched by utilizing different combinations of keywords: CPAP, obstructive sleep apnea, serum lipids, dyslipidemia, cholesterol, total cholesterol (TC), low density lipoprotein, LDL, high density lipoprotein, HDL, triglyceride, and TG. Inclusion criteria were: (1) English articles and (2) studies with an adult population with the diagnosis of OSA who were treated with CPAP. The OSA group must have cholesterol profile including TC, LDLc, HDLc, and TG, without and with CPAP treatment. Fifty-four studies were reviewed, while 29 studies pooled for MA.

RESULTS

Thirty-four datasets from 29 studies with 1,958 subjects pooled. Treatment duration range was from 2 days to 1 year. TC standardized mean differences (SMD) ranged from -41.5 to -0.077, pooled mean difference (PMD) was -5.660 (LL -6.715 to UL -4.606, p < 0.001). SMD in LDL ranged from -3.7 to 0; PMD was -0.488 (LL -0.715 to UL -0.261, p < 0.001). HDL SMD ranged from -0.498 to 1.94. The PMD was 0.207 (LL 0.05 to UL 0.364, p < 0.01). TG SMD ranged from -9.327 to 1.98; PMD was -0.054 (LL -0.124 to UL 0.016, p < 0.129).

CONCLUSIONS

CPAP treatment for OSA seems to improve dyslipidemia (decrease in total cholesterol and LDL, and increase in HDL). It does not appear to affect TG levels.

Pulmonary hypertension and right heart dysfunction in chronic lung disease

Group 3 pulmonary hypertension (PH) is a common complication of chronic lung disease (CLD), including chronic obstructive pulmonary disease (COPD), interstitial lung disease, and sleep-disordered breathing. Development of PH is associated with poor prognosis and may progress to right heart failure, however, in the majority of the patients with CLD, PH is mild to moderate and only a small number of patients develop severe PH. The pathophysiology of PH in CLD is multifactorial and includes hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, small vessel destruction, and fibrosis. The effects of PH on the right ventricle (RV) range between early RV remodeling, hypertrophy, dilatation, and eventual failure with associated increased mortality. The golden standard for diagnosis of PH is right heart catheterization, however, evidence of PH can be appreciated on clinical examination, serology, radiological imaging, and Doppler echocardiography. Treatment of PH in CLD focuses on management of the underlying lung disorder and hypoxia. There is, however, limited evidence to suggest that PH-specific vasodilators such as phosphodiesterase-type 5 inhibitors, endothelin receptor antagonists, and prostanoids may have a role in the treatment of patients with CLD and moderate-to-severe PH.

Use of pulmonary arterial hypertension-specific therapy in overweight or obese patients with obstructive sleep apnea and pulmonary hypertension

Pulmonary hypertension (PH) in overweight or obese patients with obstructive sleep apnea (OSA) may be multifactorial. The effect of pulmonary artery hypertension (PAH)-specific drugs on PH and exercise capacity in such patients is unknown. We performed a retrospective review of overweight or obese patients with OSA and PH who were treated with PAH-specific therapy in our PH clinic. We identified 9 female and 2 male patients. The mean age ± SD was 54.9 ± 9.3 years. The mean pulmonary artery pressure at the time of diagnosis of PH was 39.8 ± 16.1 mmHg. The right atrial pressure was 11.1 ± 4.5 mmHg, the pulmonary artery wedge pressure was 14.1 ± 2.9 mmHg, the cardiac index was 2.6 ± 0.5 L/min/m(2), and the pulmonary vascular resistance index was 10.6 ± 7.1 Wood units/m(2). The indications for use of PAH-specific therapy were dyspnea in association with right heart failure (n = 4), persistent PH despite compliance with nocturnal positive airway pressure (PAP) therapy (n = 4), or inability to tolerate PAP therapy (n = 3). PH was treated with an endothelin receptor antagonist (n = 8) or a phosphodiesterase-5 inhibitor (n = 3). The 6-minute walk distance (6MWD) improved significantly, from 234 ± 49.7 to 258 ± 54.6 m (24 m [95% confidence interval (CI): 6.5-341.5 m]; P = 0.014) over a period of 4.4 ± 1.8 months (n = 8) and from 241.7 ± 48.5 to 289.9 ± 91 m (48 m [95% CI: 5.5-90.8 m]; P = 0.033) in those with a longer follow-up period of 12.1 ± 6.4 months (n = 7). The systolic pulmonary artery pressure dropped significantly, from 64 ± 25.2 to 42 ± 10.4 mmHg (22 mmHg [95% CI: 4-40 mmHg]; P = 0.024) over a period of 6.1 ± 4.1 months (n = 7). In conclusion, PAH-specific therapy resulted in significant improvement in both PH and 6MWD.

Sleep apnea, heart failure, and pulmonary hypertension

Despite the emergence of sleep apnea (SA) as a significant risk factor for heart failure (HF) mortality, data indicate that SA remains under-diagnosed and under-treated. Less well established, though perhaps more emphasized, is the role of sleep apnea in pulmonary hypertension (PH). SA occurs in approximately 50 % of HF patients, and its consequences include intermittent hypoxemia, arousal, and intra-thoracic pressure swings leading to neurohormonal stimulation, oxidative stress and inflammation. While SA is also considered a cause of PH, severe PH due solely to SA is rare. Combining the results of several studies using Swan-Ganz catheters for diagnosis of PH, approximately 10 % of patients with OSA have PH. Effective treatment of SA in HF is associated with improved survival, while treatment of SA in PH is typically associated with modest hemodynamic improvement.

Effect of obstructive sleep apnea hypopnea syndrome on lipid profile: a meta-regression analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with obesity, metabolic syndrome, and dyslipidemia, which may be related to decrease androgen levels found in OSA patients. Dyslipidemia may contribute to atherosclerosis leading to increasing risk of heart disease.

METHODS

Systematic review was conducted using PubMed and Cochrane library by utilizing different combinations of key words; sleep apnea, obstructive sleep apnea, serum lipids, dyslipidemia, cholesterol, total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL), and triglyceride (TG). Inclusion criteria were: English articles, and studies with adult population in 2 groups of patients (patients with OSA and without OSA). A total 96 studies were reviewed for inclusion, with 25 studies pooled for analysis.

RESULTS

Sixty-four studies were pooled for analysis; since some studies have more than one dataset, there were 107 datasets with 18,116 patients pooled for meta-analysis. All studies measured serum lipids. Total cholesterol pooled standardized difference in means was 0.267 (p = 0.001). LDL cholesterol pooled standardized difference in means was 0.296 (p = 0.001). HDL cholesterol pooled standardized difference in means was -0.433 (p = 0.001). Triglyceride pooled standardized difference in means was 0.603 (p = 0.001). Meta-regression for age, BMI, and AHI showed that age has significant effect for TC, LDL, and HDL. BMI had significant effect for LDL and HDL, while AHI had significant effect for LDL and TG.

CONCLUSION

Patients with OSA appear to have increased dyslipidemia (high total cholesterol, LDL, TG, and low HDL).

Pulmonary hypertension due to lung disease and/or hypoxia

Pulmonary hypertension may complicate the course of patients with many forms of advanced lung disease. The cause is likely multifactorial with pathogenic pathways both common and unique to the specific disease entities. The occurrence of pulmonary hypertension is associated with worse outcomes, but whether this is an adaptive or maladaptive phenomenon remains unknown. The treatment of pulmonary hypertension with vasoactive medications in lung disease remains unproved. Specific disease phenotypes that might benefit, and those in which such therapies might be deleterious, remain to be determined.

Serum inflammatory markers in obstructive sleep apnea: a meta-analysis

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been linked to and is associated with increased cardiovascular and cerebrovascular morbidity. Ongoing inflammatory responses play an important role in this association. Multiple small size studies addressing the profile of the inflammatory markers in OSA are available therefore we performed a meta-analysis.

METHODS

Systematic review of medical literature was conducted using PubMed, Cochrane, and EMBASE databases from 1968 to 2011 by utilizing the key words obstructive sleep apnea, C-Reactive protein, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM) and Selectins. Inclusion criteria were: full text English articles; studies with adult population; reported values for at least one of the markers of interest; with at least two separate groups (subjects with OSA and control group); OSA was defined as AHI of ≥ 5/h.

RESULTS

Five hundred and twelve studies were reviewed for inclusion with 51 studies pooled for analysis (30 studies for CRP, 19 studies for TNF-α, 8 studies for ICAM, 18 studies for IL-6, six studies for VCAM and 5 studies for Selectins). The levels of inflammatory markers were higher in patients with OSA compared to control group. Standardized pooled Mean differences were calculated to be 1.77 for CRP, 1.03 for TNF-α, 2.16 for IL-6, 4.22 for IL-8, 2.93 for ICAM, 1.45 for Selectins and 2.08 for VCAM.

CONCLUSIONS

In this meta-analysis, the levels of systemic inflammatory markers were found to be higher in OSA patients compared to control subjects.

Standard nonspecific therapies in the management of pulmonary arterial hypertension

Recent advances in pulmonary arterial hypertension (PAH) research have created a new era of PAH-specific therapies. Although these therapeutics have revolutionized PAH therapy, their innovation was predated by supportive but nonspecific medical therapies adapted from their use in more common cardiopulmonary diseases. These therapies include oxygen therapy, diuretics, digoxin, anticoagulation, and high-dose calcium channel blockers. Expert opinion continues to support the use of adjunct therapies based on current pathologic understandings of PAH combined with some evidence extrapolated from small studies. This article discusses why these therapies continue to play an important role in the treatment of patients with PAH.

Treatment for sleep apnea by continuous positive airway pressure improves levels of inflammatory markers - a meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with coronary artery disease (CAD). Intermittent hypoxia associated with OSA increases sympathetic activity and may cause systemic inflammation, which may contribute to CAD in patients with OSA. Treatment with continuous positive airway pressure (CPAP) has been shown to change levels of inflammatory markers. We analyzed data from published studies by a systematic meta-analysis.

OBJECTIVE

To asses if treatment for sleep apnea by CPAP will affect levels of inflammatory markers.

DATA RESOURCES

PubMed, Embase and Cochrane library.

METHODS

Study eligibility criteria full text English studies of adult, human subjects, addressing values of at least one of the inflammatory markers before and after CPAP treatment. We used the definition of OSA as an apnea-hypopnea index (AHI) of ≥ 5/h, reported values in mean and standard deviation or median with range.

PARTICIPANTS

Adult, human.

INTERVENTIONS

CPAP treatment for OSA.

STUDY APPRAISAL AND SYNTHESIS METHOD

A total of 3835 studies were reviewed for inclusion, while 23 studies pooled for analysis. A total of 14 studies with 771 patients were pooled for C-reactive protein (CRP); 9 studies with 209 patients were pooled for tumor necrosis factor-alpha (TNF-α); and 8 studies with 165 patients were pooled for interleukin-6 (IL-6).

ENDPOINT DEFINITIONS

THE FOLLOWING INFLAMMATORY MARKERS WERE CHOSEN: CRP, TNF-α, and IL-6.

RESULTS

C-reactive protein: Study level means ranged from 0.18 to 0.85 mg/dl before CPAP treatment and 0.10 to 0.72 mg/dl after CPAP treatment. Mean differences, at a study level, ranged from -0.05 to 0.50. The pooled mean difference was 0.14 [95% confidence interval 0.08 to 0.20, p < 0.00001]. There was heterogeneity in this endpoint (df = 13, p < 0.00001, I(2) = 95%). Tumor necrosis factor-α: Study level means ranged from 1.40 to 50.24 pg/ml before CPAP treatment and 1.80 to 28.63 pg/ml after CPAP treatment. Mean differences, at a study level, ranged from -1.23 to 21.61. The pooled mean difference was 1.14 [95% confidence interval 0.12 to 2.15, p = 0.03]. There was heterogeneity in this endpoint (df = 8, p < 0.00001, I2 = 89%). Interleukin-6: Study level means ranged from 1.2 to 131.66 pg/ml before CPAP treatment and 0.45 to 66.04 pg/ml after CPAP treatment. Mean differences, at a study level, ranged from -0.40 to 65.62. The pooled mean difference was 1.01 [95% confidence interval -0.00 to 2.03, p = 0.05]. There was heterogeneity in this endpoint (df = 7, p < 0.00001, I(2) = 95%).

LIMITATIONS

Only published data. Studies pooled were mainly small, non-randomized trials.

CONCLUSION

Sleep apnea treatment with CPAP improves levels of inflammatory markers.

Pulmonary hypertension and refractory heart failure in a patient with Crow-Fukase (POEMS) syndrome

We experienced the case of a 67-year-old man with refractory heart failure. He presented with dyspnea and progressive pitting edema of the lower limbs. Diuretics were insufficient to improve his symptoms. Cardiac catheterization demonstrated pulmonary hypertension. Additional examinations confirmed polyneuropathy, organomegaly, endocrinopathy and monoclonal gammopathy. The plasma vascular endothelial growth factor (VEGF) level was 1,340 pg/mL. The patient was diagnosed with Crow-Fukase (POEMS) syndrome. Echocardiography detected left ventricular hypertrophy and diastolic dysfunction. Polysomnography demonstrated severe sleep-disordered breathing. We herein describe a case of pulmonary hypertension with Crow-Fukase syndrome accompanied by left ventricular diastolic dysfunction and sleep-disordered breathing.

World Health Organization Group III pulmonary hypertension

Pulmonary hypertension in the setting of parenchymal lung disease and conditions associated with chronic hypoxemia is commonly encountered in clinical practice and may adversely affect patients' function and mortality. Diagnosis of this subgroup of pulmonary hypertension has evolved but still requires right heart catheterization for confirmation. The primary treatment goal is optimization of the underlying parenchymal lung or hypoxemia-associated condition prior to consideration of pharmacologic therapy. Limited published experience with pulmonary hypertension-specific medications for treatment of WHO Group 3 pulmonary hypertension suggests symptomatic and functional benefit in selected individuals. The potential for worsening ventilation-perfusion matching must be considered in these cases, however, since there is a paucity of data regarding the optimal approach to treatment selection. Ongoing medication trials and further investigation of mechanisms of hypoxic pulmonary vasoconstriction provide hope for these patients who in the past often had only lung transplantation as a potential treatment option.

Effective sleep apnoea treatment improves cardiac function in patients with chronic heart failure

BACKGROUND

Sleep disordered breathing (SDB) is highly prevalent in patients with chronic heart failure (CHF) and is associated with adverse effects on cardiac geometry and function. Continuous positive airway pressure (CPAP) has been proved an effective treatment modality for obstructive sleep apnoea (OSA), whereas adaptive servoventilation (ASV) is more effective in patients with central sleep apnoea (CSA). The impact of selection of therapy and effective apnoea alleviation on cardiac performance and reverse left ventricular remodelling (r-LVR) has not yet been evaluated.

METHODS

Eighty five patients with stable CHF were screened for SDB and underwent polysomnography and treatment according to the type of SDB. Clinical evaluation and a comprehensive echocardiographic study was performed before initiation of therapy and after six months of effective treatment (ventilator use >5h/day with AHI <5 events/h).

RESULTS

Seventeen compliant patients under effective treatment were included in the analysis (8 OSA under Autoset CPAP and 9 CSA under ASV). In both groups, a significant improvement in all measured, conventional and TDI LV systolic indexes was recorded, including LVEF (32% ± 6% vs. 27% ± 6%, p<0.001). A decrease in LV end-systolic volume (189 ± 94 ml vs. 211 ± 88 ml, p=0.015, difference >10%) was indicative of r-LVR. Furthermore, RV systolic parameters were also increased (TAPSE, p<0.001; systolic TDI wave from lateral tricuspid annular aspect, p=0.001), whereas right heart dimensions and areas were diminished, indicating better pulmonary haemodynamics. Moreover, a significant improvement in patients' clinical status, as evaluated by New York Heart Association Class was also documented at the end of six months follow-up.

CONCLUSIONS

Effective alleviation of SDB in CHF patients is associated with significant improvements in LV and RV systolic function and r-LVR. Longitudinal studies are needed to evaluate effects on morbidity and mortality.

Obstructive sleep apnea syndrome

Obstructive sleep apnea (OSA) syndrome is a common but often unrecognized disorder caused by pharyngeal collapse during sleep and characterized by frequent awakenings, disrupted sleep and consequent excessive daytime sleepiness. With the increasing epidemic of obesity, the most important risk factor for OSA, prevalence of the disease will increase over the coming years thus representing an important public-health problem. In fact, it is now recognized that there is an association between OSA and hypertension, metabolic syndrome, diabetes, heart failure, coronary artery disease, arrhythmias, stroke, pulmonary hypertension, neurocognitive and mood disorders. Diagnosis is based on the combined evaluation of clinical manifestations and objective sleep study findings. Cardinal symptoms include snoring, sleepiness and significant reports of sleep apnea episodes. Polysomnography represents the gold standard to confirm the clinical suspicion of OSA syndrome, to assess its severity and to guide therapeutic choices. Behavioral, medical and surgical options are available for the treatment. Continuous positive airway pressure (CPAP) represents the treatment of choice in most patients. CPAP has been demonstrated to be effective in reducing symptoms, cardiovascular morbidity and mortality and neurocognitive sequelae, but it is often poorly tolerated. The results of clinical studies do not support surgery and pharmacological therapy as first-line treatment, but these approaches might be useful in selected patients. A better understanding of mechanisms underlying the disease could improve therapeutic strategies and reduce the social impact of OSA syndrome.

Patent foramen ovale-obstructive sleep apnea relationships: pro and cons

Patent foramen ovale (PFO) has a prevalence of 25%-27% in the general population [1] and it has been suggested to be the mediator for a wide variety of syndromes based on the paradoxical embolism. The obstructive sleep apnea syndrome (OSAS) is a common disorder in the middle-aged population. An echocardiographically visible PFO was detected in 27%-69% of patients with documented OSAS suggesting a relationship between PFO and OSAS, but the pathophysiology of this potential relationship is still unclear. It has been shown that obstructive apnea can induce right-to-left shunting (RLS) through PFO with two proposed mechanisms including a large swing in pleural pressure and pulmonary hypertension. Pulmonary artery hypertension and oxygen desaturation have been suggested to be caused by the concurrence of OSAS and PFO. Arguments against and in favour of this potential relationship are discussed in this brief review.

The sleep apnea cardiovascular endpoints (SAVE) trial: Rationale and start-up phase

THE SLEEP APNEA CARDIOVASCULAR ENDPOINTS (SAVE) STUDY (CLINICAL TRIALS REGISTRATION NUMBER: NCT00738170) is an academic initiated and conducted, multinational, open, blinded endpoint, randomised controlled trial designed to determine whether treatment of obstructive sleep apnea (OSA) with continuous positive airways pressure (CPAP) can reduce the incidence of serious cardiovascular events in patients with established cardiovascular disease. The answer to this question is of major importance to populations undergoing ageing and lifestyle changes all over the world. The SAVE study brings together respiratory, sleep and cardiovascular clinician-scientists in a unique interdisciplinary collaborative effort with industry sponsors to conduct the largest and most ambitious clinical trial yet conducted in the field of sleep apnea, with a global recruitment target of 5000 patients. Following its launch in Australia and China in late 2008, SAVE has now entered a phase of international expansion with new recruitment networks being established in New Zealand, India and Latin America. This article describes the rationale for the SAVE study, the considerations behind its design, and progress thus far in establishing the recruitment network. The report emphasises the important role that Chinese sleep and cardiovascular investigators have played in the start-up phase of this landmark international project.

Etiopathogenetic mechanisms of pulmonary hypertension in sleep-related breathing disorders

Obstructive sleep apnea syndrome is a common disorder with significant health consequences and is on the rise in consonance with the obesity pandemic. In view of the association between sleep-disordered breathing and pulmonary hypertension as depicted by multiple studies, current clinical practice guidelines categorize obstructive sleep apnea as a risk factor for pulmonary hypertension and recommend an assessment for sleep disordered breathing in evaluating patients with pulmonary hypertension. The dysregulatory mechanisms associated with hypoxemic episodes observed in sleep related breathing disorders contribute to the onset of pulmonary hypertension and identification of these potentially treatable factors might help in the reduction of overall cardiovascular mortality.

Diagnostic dilemmas in pulmonary hypertension

Dilemmas persist in the screening, assessment, and follow-up of patients with pulmonary hypertension, relating to issues of whom and how to screen, how to resolve ambiguities in the clinical classification of patients with multiple potential substrates of pulmonary vascular disease, how to interpret test results, how to integrate multiple clinical parameters into a global diagnosis, how to use ambiguous test results, how to determine disease severity and prognosis, and how to monitor patients on treatment. This article describes how to incorporate available information into the diagnostic process, and where lack of concrete data should impose caution in patient management.

Right ventricular dysfunction in chronic lung disease

Right ventricular (RV) dysfunction arises in chronic lung disease when chronic hypoxemia and disruption of pulmonary vascular beds increase ventricular afterload. RV dysfunction is defined by hypertrophy with preserved myocardial contractility and cardiac output. RV hypertrophy seems to be a common complication of chronic and advanced lung disease. RV failure is rare, except during acute exacerbations of chronic lung disease or when multiple comorbidities are present. Treatment is targeted at correcting hypoxia and improving pulmonary gas exchange and mechanics. There are no data supporting the use of pulmonary hypertension-specific therapies for patients with RV dysfunction secondary to chronic lung disease.

Hypoxic pulmonary vasoconstriction

It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.

Sleep apnea in congestive heart failure

Obstructive sleep apnea (OSA) is a form of sleep disordered breathing in which pharyngeal muscle relaxation leads to recurrent nighttime apneas and hypopneas that, through increased afterload, intermittent hypoxia, and excess sympathetic activity, weaken the already failing heart. This review presents the current evidence regarding the complex relationship between OSA and heart failure (HF), including support for OSA as both a cause and consequence of HF. The impact of OSA on other cardiovascular diseases, such as hypertension, ischemic heart disease and arrhythmias, as they relate to HF development or exacerbation, also are reviewed.

Obstructive sleep apnoea and perioperative complications in bariatric patients

BACKGROUND

The objective of this study was to determine the relationship between perioperative complications and the severity of obstructive sleep apnoea (OSA) in patients undergoing bariatric surgery who had undergone preoperative polysomnography (PSG).

METHODS

The records of 797 patients, age >18 yr, who underwent bariatric operations (442 open and 355 laparoscopic procedures) at Mayo Clinic and were assessed before operation by PSG, were reviewed retrospectively. OSA was quantified using the apnoea-hypopnoea index (AHI) as none (≤ 4), mild (5-15), moderate (16-30), and severe (≥ 31). Pulmonary, surgical, and 'other' complications within the first 30 postoperative days were analysed according to OSA severity. Logistic regression was used to assess the multivariable association of OSA, age, sex, BMI, and surgical approach with postoperative complications.

RESULTS

Most patients with OSA (93%) received perioperative positive airway pressure therapy, and all patients were closely monitored after operation with pulse oximetry on either regular nursing floors or in intensive or intermediate care units. At least one postoperative complication occurred in 259 patients (33%). In a multivariable model, the overall complication rate was increased with open procedures compared with laparoscopic. In addition, increased BMI and age were associated with increased likelihood of pulmonary and other complications. Complication rates were not associated with OSA severity.

CONCLUSIONS

In obese patients evaluated before operation by PSG before bariatric surgery and managed accordingly, the severity of OSA, as assessed by the AHI, was not associated with the rate of perioperative complications. These results cannot determine whether unrecognized and untreated OSA increases risk.

Cardiovascular consequences of sleep apnea

Cardiovascular disease has been the leading cause of death since 1900. Strategies for cardiovascular disease and prevention have helped to reduce the burden of disease, but it remains an important public health challenge. Therefore, understanding the underlying pathophysiology and developing novel therapeutic approaches for cardiovascular disease is of crucial importance. Recognizing the link between sleep and cardiovascular disease may represent one such novel approach. Obstructive sleep apnea (OSA), a common form of sleep-disordered breathing, has a high and rising prevalence in the general adult population, attributable in part to the emerging epidemic of obesity and enhanced awareness. OSA has been independently linked to specific cardiovascular outcomes such as hypertension, stroke, myocardial ischemia, arrhythmias, fatal and nonfatal cardiovascular events, and all-cause mortality. Treatment of OSA may represent a novel target to reduce cardiovascular health outcomes.

Cardiovascular complications of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common disorder with an increasing public health burden. It is characterized by repeated upper airway narrowing and closure, leading to apneas, hypopneas and increased respiratory effort-related arousals. Continuous positive airway pressure is an effective modality of treatment for OSA. Apart from being responsible for daytime sleepiness and cognitive impairment, OSA has been implicated in various systemic diseases, particularly of the cardiovascular system. This article reviews some of the extensive literature implicating OSA in the development of cardiovascular diseases and describes the intermediary pathophysiologic mechanisms involved. Repetitive nocturnal oxygen desaturation and reoxygenation and increased intrathoracic pressure changes related to OSA result in the intermediary pathophysiologic mechanisms that affect the neural, humoral, thrombotic, inflammatory and metabolic pathways responsible for the development of cardiovascular disorders. This review also examines evidence that suggests that OSA may be a specific cause of certain cardiovascular disorders.