Current Respiratory Medicine Reviews - Volume 11, Issue 4, 2015

Obstructive sleep apnea (OSA) and hypertension (HT) are widespread, sometimes associated disorders that enhance each other and result in high morbidity and mortality rates. Resistant hypertension (RHT) is a specific condition defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs (including a diuretic) at optimal doses. Given that RHT is very common in OSA patients, OSA is now considered one of the leading causes of RHT and RHT screening is mandatory in such cases. Some of the mechanisms seen in HT pathogenesis are also present (with specific particularities) in the OSA-HT association. Thus, factors like increased sympathetic tone, renin-angiotensinaldosterone system, endothelial dysfunction, vasoactive substances, inflammation, oxidative stress, nocturnal rostral fluid shift and excessive daytime sleepiness add their burden to the pathological chain, leading to both resistance and nondipping profile of HT. Consequently, we can assume that continuous positive airway pressure (CPAP) therapy in OSA patients has an impact on HT and HT resistance. This review describes the effect of CPAP on the above-mentioned links of the pathological chain, while providing information on new methods of assessing the cardiovascular risk in these patients, a history of the most important studies on the OSA-RHT association and the outcomes of a recent meta-analysis showing a positive effect of CPAP on 24-hour BP monitoring in patients with OSA and RHT compared to standard antihypertensive treatment.

Apart from the common predisposing factors of Obstructive Sleep Apnea and Hypertension, there is also a bidirectional causal relation between these two diseases. The aim of this review is to describe the pathophysiological background of the interaction between them and to highlight the potential benefits of Continuous Positive Airway Treatment (CPAP) and several antihypertensive drugs on the alleviation of both conditions.

Background: Analysis of correlation between obesity surrogates and body fat distribution in individuals with suspicion of obstructive sleep apnea syndrome (OSAS) from “Victor Babes Hospital”, Timisoara, Romania. Materials and Methods: We evaluated with polysomnography (PSG) 1277 consecutive patients referred with suspected OSAS, performing anthropological measurements, together with weight in kilograms divided by the square of height in meters (body - mass index BMI), circumference of the neck in centimetres (NC), circumference of abdomen in centimeter (AC), and the ratio of the circumference of the waist to that of the hips (waist-hip ratio W/HR). Multiple linear regression analysis with stepwise regression model used apnea - hypopnea index (AHI) as a dependent variable and variables of interest as independent variables. Results: 797 of the patients (62.41%) had obesity (with a median age 54 years), 480 patients (37.59%) presented normal BMI (median age 52). Obese subjects had significantly higher AHI: 41.25/h (25.5 - 61.3) vs 26.8/h (15.3 - 39.9) (p<0.001). Age (β=0.191, p<0.001) and W/HR (β=0.104, p=0.043) at females and AC (β=0.16, p=0.025) at males have a higher influence on AHI. AHI has a positive correlation with NC (r = 0.389, p < 0.001) and AC (r = 0.371, p < 0.001). The risk of OSAS is 7.7 higher for obese female vs normal weight (OR=7.74, 95% CI 3.52-17.02) and 6.1 higher for obese male vs normal weight (OR=6.12, 95% CI 2.66-14.1), with no significant difference between genres (Breslow- Days Test, p=0.69). Snoring had a 7.51 increased risk of having OSAS (OR=7.51, 95% CI 4.29- 13.15). Conclusion: Obesity surrogates and body fat distribution are strongly correlated with AHI. Obese females have a higher risk of OSAS. The most powerful predictor for OSAS was active smoking. Associated snoring is the most powerful predictor for OSAS.

Recent research suggests an association between the development and progression of chronic kidney disease (CKD) - which affects 10–13% of the general population and leads to high rates of morbidity - and sleep apnea (SA). SA impacts 2–4% of middle aged adults through one of its three forms: obstructive (OSA), central (CSA) and mixed sleep apnea, respectively. SA is associated with sleep fragmentation and hypoxemia during the apneic phenomena. Sleep fragmentation activates the renin-angiotensin-aldosterone system and the sympathetic nervous system, and alters the cardiovascular hemodynamic. It also results in the production of free radicals. SA is a risk factor for CKD progression because it is associated with glomerular hyper-filtration and may be an independent predictor of proteinuria. More specifically, the treatment of sleep apnea, manifested through one of its three forms - obstructive, central, and mixed, respectively - can reduce the severity of CKD and delay its progression by reducing CKD risk factors. This paper discusses the mechanisms that link CKD and sleep apnea, and suggests SA treatments with beneficial effects to CKD-related cases. Optimizing sleep duration and quality and treating sleep disorders, especially SA, we can reduce the severity of CKD and the delay of progression.

Sleep-disordered breathing (SBD), and especially sleep apnea is prevalent among pregnant women, has numerous medical consequences and is associated with an increased risk of adverse maternal and fetal outcomes. This article is an up-to-date review of pathophysiology, complications, diagnosis and treatment of sleep apnea during pregnancy. Treatment of sleep apnea includes loss of weight, the use of positive airway pressure (CPAP) and the change of sleep position.

Obstructive sleep apnea/hypopnea syndrome (OSAS) is a relatively new disease which is proven to be a major cause of morbidity and mortality worldwide and a huge problem for public health. Type 2 diabetes (T2DM) is another disease which is worldwide seen as an epidemic. The link between these two conditions makes it more important to provide a proper treatment option for such patients in order to prevent life threatening complications. This article is an up-to-date review of the relationship between OSAS and T2DM, diagnostic procedures and treatment options for patients who have both of the diseases since every particular case may be adjusted differently and may benefit from a multiple line treatment.

Patients with obstructive sleep apnea are at greater risk of cardiovascular morbidity and mortality. The prevalence of obstructive sleep apnea also seems to be higher in patients with cardiovascular conditions. Obstructive sleep apnea and coronary artery disease share some common risk factors while the pathophysiological interaction between them includes neural, humoral, mechanical and hemodynamic components. In this review we focus on the association between obstructive sleep apnea and coronary disease on the basis of their pathophysiological interaction, inflammatory mechanisms and to the effects of sleep apnea therapy on coronary disease outcomes.

Obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder that affects up to 7-10% of men and 4-5% of women. It is characterized by repeated events of complete or partial upper airway occlusion occurring during sleep, accompanied by a gradually increasing effort to breathe and terminated by an arousal when the upper airway patency is restored. The most effective treatment option for OSAS is continuous positive airway pressure (CPAP) therapy. There are numerous studies that had linked, without any scientific doubt, OSAS with cardiovascular diseases, morbidity and mortality. In the recent years it became evident as well that acute cerebrovascular events, such as stroke, are also a consequence of obstructive sleep apnea, although the pathophysiology and the mechanisms are not clear as of yet. This mini-review attempts to clarify and to highlight clinically important issues concerning sleep apnea and stroke patients with the aim of their optimal, effective and safe management.

Obstructive Sleep Apnoea Syndrome (OSAS) and Chronic Obstructive Pulmonary Disease (COPD) are common respiratory diseases, associated with significant morbidity, worldwide. They frequently co-exist and the overlap syndrome is associated with greater hypoxia and hypercapnia in comparison with COPD or OSAS alone. Unfortunately, the overlap syndrome is still underdiagnosed and undertreated in clinical practice, leading to increased morbidity and mortality. The aim of this review is to present why OSAS is more prevalent among COPD patients, how to differentiate between the common sleep alteration in COPD and the overlap syndrome, the current screening, diagnostic and therapeutic approach of the overlap syndrome.