Effects of CPAP on "vascular" risk factors in patients with obstructive sleep apnea and arterial hypertension

Effect of Continuous Positive Airway Pressure on Blood Pressure in Patients with Resistant Hypertension and Obstructive Sleep Apnea: An Updated Meta-analysis

PURPOSE OF REVIEW

The effect of continuous positive airway pressure (CPAP) on resistant hypertension in patients at high risk with obstructive sleep apnea (OSA) needs further investigation. We aimed to determine the effect of CPAP on blood pressure in patients with resistant hypertension and OSA. Databases including PubMed, EMBASE, MEDLINE, the Cochrane Library, and CMB were searched. Data were pooled using a random-effects or fixed-effects model to derive weighted mean differences (WMDs) and 95% confidence intervals (CIs).

RECENT FINDINGS

A total of 12 trials and 718 participants were included. Compared with control, CPAP significantly reduced 24-h systolic blood pressure (SBP) (WMD: - 5.92 mmHg [ - 8.72, - 3.11]; P＜0.001), 24-h diastolic blood pressure (DBP) (WMD: - 4.44 mmHg [- 6.26 , - 2.62]; P  ＜0.001),   daytime SBP (WMD: - 5.76 mmHg [ - 9.16,  - 2.36]; P ＜0.001),  daytime DBP (WMD: - 3.92 mmHg [- 5.55,  - 2.30];  nighttime SBP (WMD: - 4.87 mmHg [ - 7.96 ,  - 1.78]; P = 0.002), and nighttime DBP (WMD: - 2.05 mmHg [- 2.99,  - 1.11]; P＜0.001) in patients with resistant hypertension and OSA. CPAP improved the blood pressure both in the short (＜3 months) and long term (≥ 3  months). No significant impact on mean heart rate was noted (WMD: -2.76 beats per min [- 7.50, 1.97]; P = 0.25). CPAP treatment was associated with BP reduction in patients with resistant hypertension and OSA.

The pathogenesis of OSA-related hypertension: what are the determining factors?

Sleep-disordered breathing has a relatively high prevalence, which varies from 3-7% in males and from 2-5% in females in the adult population. Studies published in the literature have shown that sleep apnea is closely related to an increased risk of developing various pathologies, among which arterial hypertension stands out. The prevalence of hypertension in patients suffering from obstructive sleep apnea (OSA) ranges from 35-80% and appears to be related to OSA severity. Approximately 40-50% of patients affected by hypertension are also affected by OSA and this association seems to be stronger in young and middle-aged adults (<50 years of age). The primary objective of this narrative review is to provide an update on what are the main contributing comorbidities to the development of a hypertensive state in patients suffering from OSA, an independent risk factor for diurnal hypertension, implicated as a risk factor for the first stroke, recurrent stroke, and post-stroke mortality. There are a lot of factors that contribute to developing a hypertensive state in OSA patients, some more decisive, others less. More evidence from longitudinal studies is needed on the impact of OSA on cardiovascular risk in females, on the causal link between OSA and arterial hypertension or metabolic diseases, like diabetes and glucose intolerance, and the effect of different kinds of OSA treatment.

Effectiveness of Continuous Positive Airway Pressure in Treating Hypertension in Obstructive Sleep Apnea: A Traditional Review

Almost one billion individuals worldwide suffer from obstructive sleep apnea (OSA). The most widely used treatment for OSA has been continuous positive airway pressure (CPAP), but its effect on blood pressure (BP) has been challenged. Our review aims to evaluate the effects of treating OSA with CPAP on BP and BP-related morbidities in adult hypertensive patients. Medical subject headings (MeSH) terminology was used to search the PubMed Central, MEDLINE, and PubMed databases for articles on the use of CPAP in OSA patients with hypertension. We selected various forms of academic writing, encompassing complete texts that were published in the English language. The study included a total of 21 papers. OSA is a serious health concern associated with a higher risk of cardiovascular disease, kidney disease, pulmonary hypertension, and aortic stiffness, which is brought on by the periodic hypoxia caused by nocturnal respiratory episodes. For individuals with moderate-to-severe OSA, CPAP therapy has been shown to have a considerable long-term benefit with a median drop of 11 mm Hg, and high adherence results in a decrease in diastolic BP. CPAP therapy directly lowers BP in OSA patients with a body mass index (BMI) of more than 30 kg/m2 and has also demonstrated improvement in early signs of atherosclerosis with lower nocturnal systolic BP levels. OSA patients with resistant hypertension also experienced lower BP after using CPAP for a year. Therefore, our findings suggest that obesity, hypersomnolence, high nocturnal BP, prolonged CPAP usage, and resistant hypertension may all have a major impact on the BP response to CPAP therapy in individuals with severe OSA.

Continuous positive airway pressure reduces the incidence of atrial fibrillation in patients with obstructive sleep apnea: A Meta-Analysis and Systematic Review

INTRODUCTION

Obstructive sleep apnea (OSA) and atrial fibrillation (AF) are disorders that have increased in the United States during recent years. Earlier investigations have shown that underlying undiagnosed and unmanaged OSA plays a significant role in high rates and also as a trigger for newly diagnosed AF. Since the introduction of continuous positive airway pressure (CPAP) as a main therapy for OSA, more studies have evaluated the effect of CPAP on the development or recurrence of AF in OSA patients. However, sample sizes in a limited number of studies have been too small to conclude whether CPAP therapy has a significant effect on the development of AF in patients with OSA. The authors report results of their systematic review and meta-analysis summarizing what is currently known about the efficacy of CPAP for mitigating AF in patients with OSA.

METHOD

The authors systematically reviewed the published reports on CPAP use and the incidence of AF from PubMed, Google Scholar, EMBASE, Web of Science, meeting abstracts, and Cochrane databases published between January 2015 and November 2021. Study data were extracted by two reviewers and a random-effects meta-analysis was performed using RevMan version 5.4.

RESULTS

A total of 17 studies that met inclusion criteria were identified Studies included a total of 6,523 patients, 3,248 (49.8%) who used CPAP and 3,275 (50.2%) who did not use CPAP. In a random effects model, patients treated with CPAP showed a decrease in the incidence of AF (OR, 0.51; 95% CI; 0.27; 0.97, p = 0.04). High heterogeneity among the included studies was also observed (I2 = 97%).

CONCLUSION

Our results add to the increasing evidence that CPAP therapy may reduce the incidence of development of AF in patients with OSA. Prospective future studies and clinical trials are needed to refine our understanding of the relationship between OSA and AF and how CPAP may reduce cardiovascular disease development.

Benefits of continuous positive airway pressure on blood pressure in patients with hypertension and obstructive sleep apnea: a meta-analysis

This meta-analysis was performed to determine the effects of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with systemic hypertension and obstructive sleep apnea (OSA). A systematic search was conducted using PubMed, Embase, Web of Science, Cochrane Library, and clinicaltrials.gov, without language restrictions. Randomized controlled trials on the treatment of hypertension and OSA with CPAP, compared with sham CPAP or no CPAP, were reviewed. Studies were pooled to obtain weighted mean differences (WMDs) with 95% confidence intervals (CIs). Nineteen trials (enrolling 1904 participants) met the inclusion criteria. CPAP had significant effects on 24-h systolic blood pressure (SBP) (WMD -5.01 mmHg, 95% CI -6.94 to -3.08; P < 0.00001), 24-h diastolic blood pressure (DBP) (WMD -3.30 mmHg, 95% CI -4.32 to -2.28; P < 0.00001), daytime SBP (WMD -4.34 mmHg, 95% CI -6.27 to -2.40; P < 0.0001), daytime DBP (WMD -2.97 mmHg, 95% CI -3.99 to -1.95; P < 0.00001), nighttime SBP (WMD -3.55 mmHg, 95% CI -5.08 to -2.03; P < 0.00001), nighttime DBP (WMD -2.33 mmHg, 95% CI -3.27 to -1.40; P < 0.00001), office SBP (WMD -3.67 mmHg, 95% CI -5.76 to -1.58; P = 0.0006), office DBP (WMD -2.61 mmHg, 95% CI -4.25 to -0.97; P = 0.002), and heart rate (WMD -2.79 beats/min, 95% CI -4.88 to -0.71; P = 0.009). CPAP treatment was associated with BP reduction in patients with systemic hypertension and OSA, except when the follow-up period was shorter than 3 months.

Russian Medical Society for Arterial Hypertension expert consensus. Resistant hypertension: detection and management

The diagnosis of resistant arterial hypertension allows us to single out a separate group of patients in whom it is necessary to use special diagnostic methods and approaches to treatment. Elimination of reversible factors leading to the development of resistant arterial hypertension, such as non-adherence to therapy, inappropriate therapy, secondary forms of arterial hypertension, leads to an improvement in the patient's prognosis. Most patients with resistant hypertension should be evaluated to rule out primary aldosteronism, renal artery stenosis, chronic kidney disease, and obstructive sleep apnea. The algorithm for examining patients, recommendations for lifestyle changes and a step-by-step therapy plan can improve blood pressure control. It is optative to use the most simplified treatment regimen and long-acting combined drugs. For a separate category of patients, it is advisable to perform radiofrequency denervation of the renal arteries.

Auto-adaptive positive airway pressure improves lung function and arterial stiffness parameters in patients with severe obstructive sleep apnea syndrome over a 1 year follow-up

OBJECTIVE

Auto-adaptive positive airway pressure (APAP) is an emerging therapeutic modality for obstructive sleep apnea (OSA) patients. However, their associated physiological effects have not been well-defined. Therefore, we aimed to investigate the impact of a 1 year APAP treatment on lung function and arterial stiffness parameters.

APPROACH

This study enrolled male patients with newly diagnosed severe OSA who have undergone APAP treatment. A total of 35 patients completed a 1 year follow up. Blood pressure, arterial stiffness (PWV, cAIx, pAIx, cSBP), and lung function readings (FEV₁, FVC, FEV₁/FVC, PEF) were obtained basally and after 1, 3, 6, and 12 months of treatment.

MAIN RESULTS

A gradual increase in FEV₁ has been observed over the follow-up (2.92 ± 0.88 versus 3.07 ± 0.92 versus 3.18 ± 0.93 versus 3.28 ± 0.93 versus 3.41 ± 0.97 L), while PWV showed a gradual decrease over the follow-up (9.72 ± 1.64 versus 9.32 ± 1.73 versus 8.89 ± 1.65 versus 8.53 ± 1.61 versus 8.46 ± 1.60 m s^-1), as measured by absolute values. Linear mixed effects model analysis revealed a statistically significantly higher FEV₁ values (coefficient of 0.11, 0.20, and 0.33 for 3rd month, 6th month, and 12th month, respectively, P < 0.001) and lower PWV values (coefficient of -0.69, -0.63, and -0.34 for 3rd month, 6th month, and 12th month, respectively, P < 0.001), after the initiation of APAP treatment.

SIGNIFICANCE

We conclude that APAP treatment improves main lung function and arterial stiffness parameters in male patients with severe OSA over a 1 year follow-up.

Impact of CPAP on arterial stiffness in patients with obstructive sleep apnea: a meta-analysis of randomized trials

PURPOSE

This study aimed to perform a systematic review and meta-analysis of randomized trials investigating the effect of continuous positive airway pressure (CPAP) on non-invasive markers of arterial stiffness in patients with OSA.

METHODS

The purpose of the study was to evaluate the effect of CPAP on markers of arterial stiffness (pulse wave velocity (PWV) and augmentation index (Aix)) in patients with OSA. The study adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We systematically reviewed MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, and LILACS databases for randomized trials (RT) evaluating the changes in markers of arterial stiffness (pulse wave velocity (PWV) and augmentation index (Aix) comparing CPAP vs. controls in patients with OSA. Reviewer Manager version 5.3 (R Foundation for Statistical Computing, Vienna, Austria) was used to perform meta-analysis. Risk of bias analysis was performed using the Cochrane tool.

RESULTS

Of the 464 studies initially retrieved, 9 relevant studies with 685 participants were included in the analysis. The studies presented moderate risk of bias. CPAP did not significantly reduce Aix (mean difference, - 1.96 (95% confidence interval (CI) - 5.25 to 1.33), p = 0.24), whereas it significantly changed PWV (mean difference, - 0.44 (95% confidence interval (CI) - 0.76 to - 0.12), p = 0.00).

CONCLUSION

CPAP treatment was effective in improving arterial stiffness by reducing PWV in patients with OSA. Additional randomized trials, however, should be performed to confirm these findings.

Obstructive Sleep Apnea and Cardiovascular Morbidities: A Review Article

In obstructive sleep apnea (OSA), there are brief episodes of partial or total upper airway obstruction during sleep, which leads to apnea or hypopneas. Much attention is required to understand OSA's effects on the human body, owing to how common but under-diagnosed this disorder remains. Though the role of OSA in cardiovascular (CV) disease is commonly discussed, it remains unclear how it induces changes in the human body. The intermittent and recurrent hypoxia occurring at the cellular level in this condition is critical for the dramatic changes observed. Vascular endothelial cell (VEC) injury and other mechanisms seen in OSA lead to changes in the CV system. OSA can take a toll on a person's overall functioning, especially with so much importance in today's time on preventing and treating cardiac-related deaths. A total of 31 published articles were included from the PubMed database for our literature review. Most of the studies showed a strong association of OSA with hypertension, especially resistant hypertension. Findings were consistent with OSA's independent role in causing CV diseases, included heart failure, coronary artery disease (cardiac ischemia), arrhythmias, and ischemic stroke. Continuous Positive Airway Pressure (CPAP) is one of the reliable and beneficial treatments for OSA patients. OSA is a treatable and modifiable risk factor for cardiac events and related deaths. The primary purpose of our review article was to address any existing gaps between OSA and its effect on the human body with particular emphasis on cardiovascular changes.

Obstructive sleep apnoea treatment and blood pressure: which phenotypes predict a response? A systematic review and meta-analysis

The treatment for obstructive sleep apnoea (OSA) with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is associated with blood pressure (BP) reduction; however, the overall effect is modest. The aim of this systematic review and meta-analysis of randomised controlled trials (RCTs) comparing the effect of such treatments on BP was to identify subgroups of patients who respond best to treatment.The article search was performed in three different databases with specific search terms and selection criteria. From 2289 articles, we included 68 RCTs that compared CPAP or MADs with either passive or active treatment. When all the studies were pooled together, CPAP and MADs were associated with a mean BP reduction of -2.09 (95% CI -2.78- -1.40) mmHg for systolic BP and -1.92 (95% CI -2.40- -1.43) mmHg for diastolic BP and -1.27 (95% CI -2.34- -0.20) mmHg for systolic BP and -1.11 (95% CI -1.82- -0.41) mmHg for diastolic BP, respectively. The subgroups of patients who showed a greater response were those aged <60 years (systolic BP -2.93 mmHg), with uncontrolled BP at baseline (systolic BP -4.14 mmHg) and with severe oxygen desaturations (minimum arterial oxygen saturation measured by pulse oximetry <77%) at baseline (24-h systolic BP -7.57 mmHg).Although this meta-analysis shows that the expected reduction of BP by CPAP/MADs is modest, it identifies specific characteristics that may predict a pronounced benefit from CPAP in terms of BP control. These findings should be interpreted with caution; however, they are particularly important in identifying potential phenotypes associated with BP reduction in patients treated for OSA.

Construct validity and reproducibility of the six-minute step test in subjects with obstructive sleep apnea treated with continuous positive airway pressure

OBJECTIVE

To evaluate the construct validity and reproducibility of the six-minute step test (6MST) in individuals with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP).

METHODS

We evaluated 48 volunteers diagnosed with OSA and treated with CPAP for at least two months. The volunteers underwent the six-minute walk test (6MWT) and the 6MST, in random order and on different days, with an interval of, at most, seven days between the two tests.

RESULTS

A moderate positive correlation was found between the distance walked on the 6MWT and the number of steps climbed on the 6MST (r = 0.520; p < 0.001). There was no significant difference between the two 6MSTs in terms of the number of steps climbed (121.7 ± 27.1 vs. 123.6 ± 26.7). Reproducibility for performance on the 6MST and for cardiovascular variables was considered excellent (intraclass correlation coefficient > 0.8). Regarding cardiovascular responses, the 6MST produced higher values than did the 6MWT for HR at six minutes, percent predicted maximum HR, and leg fatigue at six minutes, as well as for systolic blood pressure at six minutes and at one minute of recovery.

CONCLUSIONS

The 6MST is valid and reproducible, producing greater cardiovascular stress than does the 6MWT. However, the 6MST is also characterized as a submaximal test for the assessment of exercise tolerance in individuals with OSA treated with CPAP.

Normotensive patients with obstructive sleep apnoea: changes in 24-h ambulatory blood pressure monitoring with continuous positive airway pressure treatment

BACKGROUND

Continuous positive airway pressure (CPAP) treatment reduces blood pressure (BP) in obstructive sleep apnoea (OSA) and hypertensive patients, but there is a lack of data about the effects of CPAP on the BP in normotensive patients.

OBJECTIVE

The aim of the study was to evaluate BP changes in normotensive OSA individuals receiving CPAP treatment.

METHODS

We selected 131 normotensive outpatients with an apnoea/hypopnoea index (AHI) greater than 15 events/hour who required CPAP treatment. All patients underwent a sleep study and 24-h ambulatory BP monitoring (ABPM) at baseline and after 6 months. In addition, the patients were assessed for the presence of baseline masked hypertension, defined as office BP less than 140/90 mmHg and increased BP on 24-h ABPM (mean 24-h BP ≥130/80 mmHg).

RESULTS

After 6 months of CPAP treatment, a mild reduction in all 24-h ABPM variables was observed, but only the mean 24-h DBP [-1.39 mmHg, 95% confidence interval (95% CI), -2.50 to -0.27], mean daytime DBP (-1.39 mmHg, 95% CI -2.56 to -0.22) and the mean 24-h ambulatory BP (-1.80 mmHg, 95% CI, -3.16 to -0.44) reached statistical significance. The reduction was primarily due to BP changes in individuals with masked hypertension who displayed a mean BP reduction of -4.78 mmHg (-7.25 to -2.30 mmHg). Consistent with a circadian BP pattern, a reduction in mean nocturnal BP of -4.73 mmHg (-7.39 to -2.06 mmHg) was observed at 6 months in nondippers; in contrast, the mean nocturnal BP in dippers increased by 2.61 mmHg (0.60-4.62 mmHg).

CONCLUSION

Our findings suggest that the CPAP effects may be different in normotensive outpatients depending on the presence of undiagnosed masked hypertension and the dipping pattern. Therefore, it is important to consider measuring ABPM in this type of patient.

"Sleep disordered breathing and ECG R-wave to radial artery pulse delay, The Multi-Ethnic Study of Atherosclerosis"

BACKGROUND

Electrocardiography R-wave to radial artery pulse delay (RRD) represents pulse transit time inclusive of pre-ejection period (PEP) and arterial pulse propagation time. RRD is proposed to largely reflect arterial stiffness when PEP is accounted for (shorter RRD = higher arterial stiffness). Sleep disordered breathing (SDB) causes intermittent hypoxemia and sympathetic activation, which negatively influences vascular function. We aimed to examine the association of measures of SDB with RRD.

METHODS

Our sample consisted of participants in the Multi-Ethnic Study of Atherosclerosis without prevalent cardiovascular disease who underwent a daytime arterial elasticity exam, cardiac magnetic resonance imaging (MRI), and overnight polysomnography. SDB measures of interest included apnea hypopnea index (AHI) and oxygen desaturation index (ODI) (N = 1173). RRD was regressed on each measure of SDB separately, with adjustment for other cardiovascular risk factors as well as for correlates of the PEP, another component of RRD, by including cardiac MRI measures of contractility and preload.

RESULTS

In multivariate analysis, among measures of SDB, ODI, a marker of intermittent hypoxemia, was inversely associated with RRD (β = -60.2 msec per SD [15.5/hr], p = 0.04). No significant association was found with AHI. In gender stratified analyses, ODI and AHI were predictive of RRD in men only (β = -111.3 msec per SD [15.5/hr], p = 0.01 and β = -100.3 msec per SD [16.1/hr], p = 0.02 respectively).

CONCLUSION

Severity of SDB as measured by ODI was associated with RRD, a marker of arterial stiffness. Thus, association of RRD with measures of SDB appears to be gender-dependent.

Arterial stiffness alteration and obstructive sleep apnea in an elderly cohort free of cardiovascular event history: the PROOF cohort study

INTRODUCTION

Several studies suggest in middle-aged subjects a relationship between arterial stiffness, a cardiovascular risk marker, and moderate to severe obstructive sleep apnea (OSA). No extensive data are present in older subjects. This study explores this association in a sample of healthy older subjects suffering OSA.

METHODS

A total of 101 volunteers aged 75.3 ± 0.7 years were examined at the hospital sleep center. Each subject was assessed for medical history, body mass index and 24-h blood pressure measures, biological blood samples, and home polygraphy in 2002-2003 (P2) as well as in 2009-2010 (P4). Arterial stiffness was also assessed using carotid-femoral and carotid-radial pulse wave velocity (cfPWV and crPWV) during P4 examination.

RESULTS

The total group consisted of 59 women and 42 men with a mean apnea-hypopnea index (AHI) of 17.8 ± 12.1 and a mean oxygen desaturation index (ODI) of 9.8 ± 8.9. No-OSA (AHI < 15) represented 50% of the sample, and severe cases (AHI > 30) 17%. No significant differences had been founded between men and women for blood pressure, cfPWV, and crPWV. Considering the severity of the AHI, no significant differences between groups were present for PWV and blood pressure values. No difference for PWV was present for subjects with and without hypertension. No correlation was found between PWV value and AHI and ODI values at P2 or between P2 and P4 visits. cfPWV was higher in patients demonstrating incident hypertension during the follow-up.

CONCLUSIONS

In this sample of older subjects, PWV is not affected by AHI and ODI but was associated with incident hypertension. These results may suggest potential protective and adaptive mechanisms in older sleep apnea patients.

CLINICAL TRIAL REGISTRATIONS

NCT 00759304 and NCT 00766584 .

The Use of Precision Medicine to Manage Obstructive Sleep Apnea Treatment in Patients with Resistant Hypertension: Current Evidence and Future Directions

PURPOSE OF REVIEW

The significant prevalence of resistant hypertension (RH) and the high cardiovascular risk of the population of patients with RH have indicated the necessity to identify its main causes. Among these, obstructive sleep apnea (OSA) is considered the most well-established cause.

RECENT FINDINGS

In recent years, several studies have shown a beneficial effect of continuous positive airway pressure (CPAP) treatment on blood pressure (BP), but this effect exhibits great variability. The diagnosis and management of OSA in patients with RH suggest a clinical option for a phenotype of patients for whom therapeutic strategies are limited to pharmaceutical therapy and renal denervation. However, the great variability in the CPAP response has increased the necessity to develop instruments to identify patients who could benefit from a treatment that reduces BP. Application of precision medicine to these patients should be considered as a first-line intervention to avoid the prescription of ineffective treatments and excessive consumption of pharmacological drugs that do not ameliorate the cardiovascular risk.

Rationale and Methodology of the SARAH Trial: Long-Term Cardiovascular Outcomes in Patients With Resistant Hypertension and Obstructive Sleep Apnea

INTRODUCTION

Patients with resistant hypertension (RH) have a high risk of developing cardiovascular events; therefore, new therapeutic approaches to better control blood pressure may be useful in improving cardiovascular outcomes. The prevalence of obstructive sleep apnea (OSA) is very high among patients with RH. Continuous positive airway pressure (CPAP) has been shown to be an effective treatment for reducing blood pressure in patients with RH. Nevertheless, the long-term effect of CPAP treatment on cardiovascular outcomes has not been explored. The main objective of the SARAH study is to assess the impact of OSA and its treatment on cardiovascular outcomes (morbidity and mortality) in patients with RH.

METHODS

This study is a multi-center, prospective, observational cohort study. A total of 1371 patients with RH will be enrolled in the study and followed once a year for five years. At inclusion, ambulatory blood pressure monitoring (ABPM) and a sleep study will be performed in all subjects. Socio-demographic, clinical and cardiovascular variables will be collected at baseline and follow-up. Subsequently, subjects with OSA will be managed according to local standard practice. Based on the OSA diagnosis and its treatment, three cohorts of subjects with RH will be defined: non-OSA, treated OSA and non-treated OSA.

CONCLUSIONS

This study will contribute to elucidating the long-term impact of OSA treatments on blood pressure control and cardiovascular outcomes in patients with RH. These results will contribute to improve the cardiovascular prognosis of patients with RH.

Effects of continuous positive airway pressure on cardiovascular biomarkers in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

PURPOSE

Obstructive sleep apnea (OSA) is associated with increased levels of systemic inflammatory markers, increased arterial stiffness, and endothelial dysfunction, which may lead to increased cardiovascular risk. We aimed to quantify the effects of continuous positive airway pressure (CPAP) on cardiovascular biomarkers and to establish predictors of response to CPAP.

METHODS

We searched PubMed and the Cochrane Library from inception to May 31, 2017. Randomized controlled trials (RCTs) assessing the efficacy of CPAP on high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), tumor necrosis factor- alpha (TNF-α), augmentation index (AIx), pulse wave velocity (PWV), and flow-mediated dilatation (FMD) in patients with OSA were selected by consensus.

RESULTS

We included 15 RCTs comprising 1090 patients in the meta-analysis. The pooled standard mean difference (SMD) of effect of CPAP on hs-CRP was - 0.64 (95% confidence interval (CI) - 1.19 to - 0.09; P = 0.02). CPAP was associated with a reduction in AIx of 1.53% (95% CI, 0.80 to 2.26%; P < 0.001) and a significant increase in FMD of 3.96% (95% CI 1.34 to 6.59%; P = 0.003). Subgroup analyses found CPAP was likely to be more effective in improving FMD levels in severe OSA patients or patients with effective CPAP use ≥ 4 h/night.

CONCLUSIONS

Among patients with OSA, CPAP improves inflammatory marker hs-CRP, arterial stiffness marker AIx, and endothelial function marker FMD. These biomarkers may provide information related to response to treatment. Future studies will need to clarify the efficacy of these biomarkers in assessing cardiovascular risk reduction among OSA treated with CPAP.

Effect of CPAP, Weight Loss, or CPAP Plus Weight Loss on Central Hemodynamics and Arterial Stiffness

Obesity and obstructive sleep apnea tend to coexist. Little is known about the effects of obstructive sleep apnea, obesity, or their treatment on central aortic pressures and large artery stiffness. We randomized 139 adults with obesity (body mass index >30 kg/m2) and moderate-to-severe obstructive sleep apnea to (1) continuous positive airway pressure (CPAP) therapy (n=45), (2) weight loss (WL) therapy (n=48), or (3) combined CPAP and WL (n=46) for 24 weeks. We assessed the effect of these interventions on central pressures and carotid-femoral pulse wave velocity (a measure of large artery stiffness), measured with arterial tonometry. Central systolic pressure was reduced significantly only in the combination arm (-7.4 mm Hg; 95% confidence interval, -12.5 to -2.4 mm Hg; P=0.004), without significant reductions detected in either the WL-only (-2.3 mm Hg; 95% confidence interval, -7.5 to 3.0; P=0.39) or the CPAP-only (-3.1 mm Hg; 95% confidence interval, -8.3 to 2.0; P=0.23) arms. However, none of these interventions significantly changed central pulse pressure, pulse pressure amplification, or the central augmentation index. The change in mean arterial pressure (P=0.008) and heart rate (P=0.027) induced by the interventions was significant predictors of the change in carotid-femoral pulse wave velocity. However, after adjustment for mean arterial pressure and heart rate, no significant changes in carotid-femoral pulse wave velocity were observed in any group. In obese subjects with obstructive sleep apnea, combination therapy with WL and CPAP is effective in reducing central systolic pressure. However, this effect is largely mediated by changes in mean, rather than central pulse pressure. WL and CPAP, alone or in combination, did not reduce large artery stiffness in this population.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00371293.

Review of and Updates on Hypertension in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a prevalent sleep disorder as is hypertension (HTN) in the 21st century with the rising incidence of obesity. Numerous studies have shown a strong association of OSA with cardiovascular morbidity and mortality. There is overwhelming evidence supporting the relationship between OSA and hypertension (HTN). The pathophysiology of HTN in OSA is complex and dependent on various factors such as sympathetic tone, renin-angiotensin-aldosterone system, endothelial dysfunction, and altered baroreceptor reflexes. The treatment of OSA is multifactorial ranging from CPAP to oral appliances to lifestyle modifications to antihypertensive drugs. OSA and HTN both need prompt diagnosis and treatment to help address the growing cardiovascular morbidity and mortality due to these two entities.

Effects of continuous positive airway pressure on blood pressure in patients with resistant hypertension and obstructive sleep apnea: a systematic review and meta-analysis of six randomized controlled trials

OBJECTIVE

To evaluate systematically the effects of continuous positive airway pressure (CPAP) on blood pressure in patients with resistant hypertension and obstructive sleep apnea (OSA).

METHODS

The Cochrane Library, PubMed, ScienceDirect, and the Web of Science were searched for studies investigating the effects of CPAP on blood pressure in patients with resistant hypertension and OSA. The selected studies underwent quality assessment and meta-analysis, as well as being tested for heterogeneity.

RESULTS

Six randomized controlled trials were included in the meta-analysis. The pooled estimates of the changes in mean systolic blood pressure and mean diastolic blood pressure (as assessed by 24-h ambulatory blood pressure monitoring) were -5.40 mmHg (95% CI: -9.17 to -1.64; p = 0.001; I2 = 74%) and -3.86 mmHg (95% CI: -6.41 to -1.30; p = 0.00001; I2 = 79%), respectively.

CONCLUSIONS

CPAP therapy can significantly reduce blood pressure in patients with resistant hypertension and OSA.

Derived Arterial Stiffness is Increased in Patients with Obstructive Sleep Apnea and Periodic Limb Movements during Sleep

STUDY OBJECTIVES

Both periodic limb movements during sleep (PLMS) and obstructive sleep apnea (OSA) have been associated with increased risk of cardiovascular disease (CVD). OSA has also been linked to increased large arterial stiffness, which is considered an independent risk factor for CVD. We utilized a previously validated index of large artery stiffness (SIDVP) derived from the digital volume pulse (DVP) to seek comparison in patients with PLMS and OSA.

METHODS

Forty-nine adult male subjects, without known comorbidities that could affect arterial stiffness or on vasoactive medication, were retrospectively identified and categorized into controls (n = 8), PLMS (n = 13), OSA (n = 17), and OSA/PLMS (n = 11). The cutoff for PLMS was a periodic limb movement index (PLMI) > 15 events/h, and for OSA an apnea-hypopnea index (AHI) > 10 events/h. SIDVP was derived from the raw data of photoplethysmography of the nocturnal polysomnography, averaged for 2 min prior to sleep study initiation (baseline), after completion in the morning, and every half hour after sleep onset.

RESULTS

The groups were age/body mass index-matched. Controls showed lower baseline, morning, and overall SIDVP compared to the other groups (p < 0.01). Patients with PLMS (PLMI: 50.69 ± 9.7 events/h) and the OSA group (AHI: 29.7 ± 2 events/h) demonstrated similar overall SIDVP (6.78 ± 0.08 versus 6.94 ± 0.04, respectively, p = 0.5), whereas the OSA/PLMS (AHI: 29.35 ± 8, PLMI: 50.63 ± 7.2) group demonstrated the highest (7.40 ± 0.06, p < 0.001).

CONCLUSIONS

Based on an easily reproducible and applicable marker of large arterial stiffness, patients with significant PLMS had higher SIDVP when compared to controls and comparable to those with moderate/severe OSA. The OSA/PLMS group had the highest SIDVP, implying a possible additive effect of OSA and PLMS on arterial stiffness.

Critical review: CPAP and weight management of obstructive sleep apnea cardiovascular co-morbidities

The cardiovascular co-morbidities of obstructive sleep apnea (OSA) are similar to those of obesity. Cardiovascular co-morbidities often are the cause of adverse outcomes in overweight/obese OSA patients. Continuous positive airway pressure (CPAP) therapy resolves the symptoms of OSA, but may, or may not lead to improvement of a given cardiovascular co-morbidity. The impact of CPAP on cardiovascular risk variables, adverse cardiovascular events in overweight/obese OSA patients has been evaluated primarily in prospective, uncontrolled cohort studies. These studies show improvement in myocardial and endothelial function, blood pressure, left ventricular performance and stroke survival. Randomized controlled studies (RCTs) examining the effect of weight management on cardiovascular risk factors and disease outcomes show that intentional weight loss leads to improvement in cardiovascular risk, hypertension, coronary artery disease, but not in stroke. Weight loss improves mortality in relatively healthy overweight/obese populations, but possibly not in all groups with cardiometabolic diseases. Clinicians caring for overweight/obese OSA patients should consider the advantages of incorporating weight management into their treatment programs for such patients.

Effects of continuous positive airway pressure on blood pressure in patients with resistant hypertension and obstructive sleep apnea: a meta-analysis

OBJECTIVE

To systematically analyze the studies that have examined the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with resistant hypertension and obstructive sleep apnea (OSA).

METHODS

Design - meta-analysis of observational studies and randomized controlled trials (RCTs) indexed in PubMed and Ovid (All Journals@Ovid). participants: individuals with resistant hypertension and OSA; interventions - CPAP treatment.

RESULTS

A total of six studies met the inclusion criteria for preintervention to postintervention analyses. The pooled estimates of mean changes after CPAP treatment for the ambulatory (24-h) SBP and DBP from six studies were -7.21 mmHg [95% confidence interval (CI): -9.04 to -5.38; P < 0.001; I² 58%) and -4.99 mmHg (95% CI: -6.01 to -3.96; P < 0.001; I² 31%), respectively. The pooled estimate of the ambulatory SBP and DBP from the four RCTs showed a mean net change of -6.74 mmHg [95% CI: -9.98 to -3.49; P < 0.001; I² 61%] and -5.94 mmHg (95% CI: -9.40 to -2.47; P = 0.001; I² 76%), respectively, in favor of the CPAP group.

CONCLUSION

The pooled estimate shows a favorable reduction of BP with CPAP treatment in patients with resistant hypertension and OSA. The effects sizes are larger than those previously reported in patients with OSA without resistant hypertension.

Effect of Continuous Positive Airway Pressure on Cardiovascular Biomarkers: The Sleep Apnea Stress Randomized Controlled Trial

BACKGROUND

Although existing research highlights the relationship of OSA and cardiovascular disease, the effect of OSA treatment on cardiovascular biomarkers remains unclear. We evaluated the effect of OSA treatment on oxidative stress/inflammation measures.

METHODS

We conducted a parallel, randomized controlled trial in moderate to severe OSA (apnea-hypopnea index ≥ 15) patients to examine effects of 2-month CPAP vs sham-CPAP on the primary outcome of oxidative stress/inflammation (F2-isoprostanes: ng/mg) and myeloperoxidase: pmol/L) and secondary oxidative stress measures. Exploratory secondary analyses included vascular and systemic inflammation markers. Linear models adjusted for baseline values examined effect of CPAP on biomarker change (least squares means, 95% CI) including secondary stratified analyses examining CPAP adherence and degree of hypoxia.

RESULTS

Of 153 participants, 76 were randomized to CPAP and 77 to sham-CPAP. In an intent-to-treat analyses, no significant change was observed in the sham and CPAP groups respectively: F2-isoprostanes (-0.02 [-0.12 to 0.10] vs -0.08 [-0.18 to 0.03]) or myeloperoxidase (-3.33 [-17.02 to 10.37] vs -5.15 [-18.65 to 8.35]), nor other oxidative markers; findings that persisted in analyses stratified by adherence and hypoxia. Exploratory analyses revealed percentage reduction of soluble IL-6 receptor (ng/mL) levels (-0.04 [-0.08 to -0.01] vs 0.02 [-0.02 to 0.06], P = .019) and augmentation index (%) (-6.49 [-9.32 to -3.65] vs 0.44 [-2.22 to 3.10], P < .001) with CPAP compared with sham, respectively.

CONCLUSIONS

In moderate to severe OSA, 2-month CPAP vs sham did not reduce oxidative stress despite consideration of a broad range of measures, positive airway pressure adherence, and hypoxia burden. These findings suggest that nonoxidative stress pathways primarily modulate OSA-related cardiovascular consequences.

TRIAL REGISTRATION

ClinicalTrials.govNCT00607893.

Effectiveness of continuous positive airway pressure in lowering blood pressure in patients with obstructive sleep apnea: a critical review of the literature

Obstructive sleep apnea (OSA) is an extremely common comorbid condition in patients with hypertension, with a prevalence of ~50%. There is growing evidence suggesting that OSA is a secondary cause of hypertension, associated with both poor blood pressure (BP) control and target organ damage in patients with hypertension. The application of continuous positive airway pressure (CPAP) during sleep is the gold standard treatment of moderate- to-severe OSA and very effective in abolishing obstructive respiratory events. However, several meta-analyses showed that the overall impact of CPAP on BP is modest (~2 mmHg). There are several potential reasons for this disappointing finding, including the heterogeneity of patients studied (normotensive patients, controlled, and uncontrolled patients with hypertension), non-ideal CPAP compliance, clinical presentation (there is some evidence that the positive impact of CPAP on lowering BP is more evident in sleepy patients), and the multifactorial nature of hypertension. In this review, we performed a critical analysis of the literature evaluating the impact of CPAP on BP in several subgroups of patients. We finally discussed perspectives in this important research area, including the urgent need to identify predictors of BP response to CPAP and the importance of precision medicine in this scenario.

Association between self-reported snoring and arterial stiffness: data from the Brisighella Heart Study

The correlation of both obstructive sleep apnoea syndrome (OSAS) and snoring with cardiovascular risk is well known, but its investigation is complex and not suitable for studying large cohorts of subjects. Thus, we prospectively evaluated 1476 non-pharmacologically treated subjects selected from the last survey of the Brisighella Heart Study. Snoring and sleep apnoea were investigated asking the subjects if they were aware of snoring during the night, and if this was associated with episodes of apnoea. A full set of clinical and laboratory parameters were evaluated, while augmentation index (AIx), and pulse wave velocity (PWV) were recorded with the Vicorder(®) apparatus. A logistic regression analysis identifies as main independent predictors of AIx age (OR 1.058, 95% CI 1.043-1.065, p < 0.001), Body Mass Index (OR 1.046, 95% CI 1.014-1.079, p = 0.005), and apolipoprotein B (OR 1.014, 95% CI 1.004-1.023, p = 0.001). The main independent predictors of PWV are snoring (OR 1.215, 95% CI 1.083-1.390, p < 0.001), and snoring with apnoea (OR 1.351, 95% CI 1.135-1.598, p = 0.014), age (OR 1.078, 95% CI 1.052-1.089, p < 0.001), serum uric acid [SUA] (OR 1.093, 95% CI 1.026-1.151, p < 0.001) and mean arterial pressure (OR 1.042, 95% CI 1.024-1.056, p < 0.001). In conclusion, in our cohort of overall healthy subjects, self-reported snoring and sleep apnoea are independently associated with a higher PVW, and AIx is statistically significantly higher in snorers with or without sleep apnoea than in non-snorers. Body Mass Index and apolipoprotein B are associated with AIx, while SUA and mean arterial pressure are related to PWV.

Relationship Between OSA and Hypertension

There is a bidirectional association between OSA and systemic hypertension. The strengths of this relationship appear to be modulated by factors such as age, sex, and somnolence. The 24-h BP circadian pattern also appears to be influenced by OSA. Patients with this syndrome exhibit a high prevalence of nondipping or riser circadian patterns, which are related to clinical and subclinical organ damage in the heart and brain. However, the influence of OSA on nocturnal hypertension development has not yet been clarified. A special area of interest is the recognized relationship between OSA and resistant hypertension. The majority of patients with resistant hypertension suffer OSA. CPAP treatment significantly reduces BP in such patients and could play a clinical role in the management of BP in these patients. Several meta-analyses have demonstrated a concordant mild effect of CPAP on systemic hypertension. This effect is related to CPAP compliance, somnolence status, and baseline BP. The effects of oral appliances on BP in patients with OSA must be evaluated in randomized controlled trials. In the absence of additional data reported by clinical studies on other antihypertensive drug treatments, diuretics, particularly antialdosteronic diuretic agents, should be considered the first-line antihypertensive drug treatment in patients with OSA. By reducing parapharyngeal edema and secondary upper airway obstruction, these drugs appear to improve OSA severity and also to reduce BP.

Treatment of Sleep Apnea With CPAP Lowers Central and Peripheral Blood Pressure Independent of the Time-of-Day: A Randomized Controlled Study

BACKGROUND

Obstructive sleep apnea (OSA) is a risk factor for hypertension and randomized controlled trials have shown that OSA treatment with continuous positive airway pressure (CPAP) reduces peripheral blood pressure and arterial stiffness. Arterial stiffness is known to augment central aortic blood pressure independent of peripheral brachial blood pressure. Currently, it is unclear whether the reduction in blood pressure with CPAP is similar between central and peripheral sites. It is also unknown whether there are any time-of-day influences on central blood pressure changes after CPAP.

METHODS

Thirty-eight patients received therapeutic and sham CPAP in random order for 8 weeks each with an intervening 1-month washout. Peripheral and central blood pressure and arterial stiffness (augmentation index and time to reflection) were measured by pulse wave analysis at end-of-treatment visits. Measurements were taken in the afternoon (~2 pm) and the next morning (~9 am).

RESULTS

Compared to sham, CPAP significantly reduced central systolic (mean difference: -4.1 mm Hg; P = 0.003), central diastolic (-3.9 mm Hg; P = 0.0009), peripheral systolic (-4.1mm Hg; P = 0.004), and peripheral diastolic (-3.8 mm Hg; P = 0.001) blood pressure. These effects were not influenced by time-of-day. Time to reflection was improved with CPAP compared to sham (3.7 ms; P = 0.01). There was no overall difference in augmentation index however when examined by time-of-day, a modest reduction with CPAP was observed in the morning (-2.5%; P = 0.03) but not in the evening (0.12%; P = 0.91).

CONCLUSION

CPAP reduces both central and peripheral blood pressure independent of the time-of-day. In contrast, modest improvements in conduit arterial stiffness after CPAP may only occur in the morning.

The utility of three screening questionnaires for obstructive sleep apnea in a sleep clinic setting

PURPOSE

The aim of this study was to determine the diagnostic value of three screening questionnaires in identifying Korean patients at high risk for obstructive sleep apnea (OSA) in a sleep clinic setting in Korea.

MATERIALS AND METHODS

Data were collected from 592 adult patients with suspected OSA who visited a sleep center. All patients completed the Sleep Apnea of Sleep Disorder Questionnaire (SA-SDQ), the Berlin questionnaire, and the STOP-Bang questionnaire. Estimated OSA risk was compared to a diagnosis of OSA. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each questionnaire.

RESULTS

The prevalence of OSA was 83.6% using an apnea-hypopnea index (AHI) ≥5/h and 58.4% for an AHI ≥15/h. The STOP-Bang questionnaire had a high sensitivity (97% for AHI ≥5/h, 98% for AHI ≥15/h), but the specificity was low (19% and 11%, respectively). In contrast, the sensitivity of the SA-SDQ was not high enough (68% for AHI ≥5/h, 74% for AHI ≥15/h) to be useful in a clinical setting, whereas the specificity was relatively good (66% and 61%, respectively). The sensitivity and specificity values of the Berlin questionnaire fell between those of the STOP-Bang questionnaire and the SA-SDQ.

CONCLUSION

The STOP-Bang questionnaire may be useful for screening OSA in a sleep clinic setting, but its specificity is lower than the acceptable level for this purpose. A new screening questionnaire with a high sensitivity and acceptable specificity is therefore needed in a sleep clinic setting.

Treatment-induced changes in ambulatory arterial stiffness index: one-year prospective study and meta-analysis of evidence

The ambulatory arterial stiffness index (AASI) has been introduced as an index of arterial function, predicting cardiovascular events. However, treatment-induced changes in AASI are rather equivocal. This study aims to: (i) present the results of treatment-induced changes in AASI in untreated subjects with elevated blood pressure (BP), subjected to antihypertensive treatment for 1 year and (ii) perform a meta-analysis of studies reporting on treatment-induced change in AASI. A total of 104 subjects (mean age 51.4±10.3 years, 62% males, mean follow-up: 13.6±2.4 months) were analyzed. Despite significant reductions in 24-h ambulatory systolic/diastolic BP, pulse pressure and pulse wave velocity (mean change: -15.9±12/-10.4±7.6 mm Hg, -5.4±6.8 mm Hg, -0.7±1.9 m s(-1), respectively, all P<0.05), there was no significant change (Follow up-Baseline) in AASI values (mean change: 0.01±0.17, P=not significant). The treatment-induced change in AASI was correlated with baseline AASI (r=-0.61), baseline 24-h pulse pressure (-0.26), treatment-induced change in 24-h pulse pressure (0.26) and in systolic/diastolic nocturnal dipping (-0.25/-0.40, respectively). Meta-analysis of eight trials (n=990) revealed a marginal decrease in AASI with antihypertensive treatment (pooled change: -0.018 (95% confidence interval (CI): -0.033,-0.003)). When the analysis was restricted to data with renin-angiotensin system blockers (n=755, 76% of total), the results did not significantly change (pooled change -0.028 (95% CI -0.048, -0.007)). In conclusion, although AASI is an independent predictor of cardiovascular events, its response to antihypertensive treatment is only marginal and clinically uncertain, which may render its use as a therapeutic target in clinical practice questionable.

The efficacy of antihypertensive drugs in chronic intermittent hypoxia conditions

Sleep apnea/hypopnea disorders include centrally originated diseases and obstructive sleep apnea (OSA). This last condition is renowned as a frequent secondary cause of hypertension (HT). The mechanisms involved in the pathogenesis of HT can be summarized in relation to two main pathways: sympathetic nervous system stimulation mediated mainly by activation of carotid body (CB) chemoreflexes and/or asphyxia, and, by no means the least important, the systemic effects of chronic intermittent hypoxia (CIH). The use of animal models has revealed that CIH is the critical stimulus underlying sympathetic activity and hypertension, and that this effect requires the presence of functional arterial chemoreceptors, which are hyperactive in CIH. These models of CIH mimic the HT observed in humans and allow the study of CIH independently without the mechanical obstruction component. The effect of continuous positive airway pressure (CPAP), the gold standard treatment for OSA patients, to reduce blood pressure seems to be modest and concomitant antihypertensive therapy is still required. We focus this review on the efficacy of pharmacological interventions to revert HT associated with CIH conditions in both animal models and humans. First, we explore the experimental animal models, developed to mimic HT related to CIH, which have been used to investigate the effect of antihypertensive drugs (AHDs). Second, we review what is known about drug efficacy to reverse HT induced by CIH in animals. Moreover, findings in humans with OSA are cited to demonstrate the lack of strong evidence for the establishment of a first-line antihypertensive regimen for these patients. Indeed, specific therapeutic guidelines for the pharmacological treatment of HT in these patients are still lacking. Finally, we discuss the future perspectives concerning the non-pharmacological and pharmacological management of this particular type of HT.

Prevalence of hypertension and circadian blood pressure variations in patients with obstructive sleep apnoea-hypopnoea syndrome

OBJECTIVE

To investigate the prevalence of hypertension and circadian blood pressure (BP) variations in patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS).

METHODS

Patients referred to a sleep clinic underwent polysomnography with measurement of BP at four time points. They were classified into four groups (control, and mild, moderate or severe sleep apnoea) using the apnoea-hypopnoea index (AHI). Circadian variation was assessed using night-time to daytime mean BP (R(N/D)) and morning to evening mean BP (R(M/E)) ratios.

RESULTS

Hypertension was significantly more common in patients with OSAHS (50.5%) than in controls (30.4%). AHI was positively correlated with hypertension after controlling for related confounders. Mean BP values at all four time points rose with increasing AHI. The increase in night-time and morning values was more pronounced than the increase in daytime and evening values in patients with OSAHS, resulting in loss of the normal BP diurnal rhythm. The R(N/D) and R(M/E) ratios increased with increasing AHI. Daytime BP was significantly correlated with AHI and the lowest oxygen saturation value.

CONCLUSION

OSAHS was shown to be an independent risk factor for hypertension. It was also associated with loss of the normal BP diurnal rhythm.

The effect of continuous positive airway pressure therapy on blood pressure and arterial stiffness in hypertensive patients with obstructive sleep apnea

AIM

We aimed to evaluate the effect of continuous positive airway pressure (CPAP) therapy on blood pressure (BP) and arterial stiffness in hypertensive patients with obstructive sleep apnea (OSA).

PATIENTS AND METHODS

We studied 38 hypertensive patients who suffered from severe OSA. Ambulatory BP measurement was performed at baseline and after at least 3 months of uninterrupted CPAP therapy. In 19 of these patients, we also measured pulse wave velocity (PWV) at baseline, after the first night of CPAP therapy and at 3 months. Fifteen normotensive subjects without OSA comprised the control group.

RESULTS

CPAP therapy reduced systolic BP from 141.5 ± 12.1 to 133.5 ± 9.7 mmHg (p = 0.007) and diastolic BP from 87.8 ± 6.8 to 83 ± 5.4 mmHg (p = 0.004). CPAP also reduced the PWV from 8.81 ± 1.4 to 8.18 ± 1 m/s after the first night of CPAP therapy (p = 0.003) and to 7.37 ± 1 m/s at 3 months (p = 0.007).

CONCLUSIONS

To the best of our knowledge, this is the first study demonstrating that CPAP therapy in hypertensive patients with OSA improves arterial stiffness from the first night and that this favorable effect is maintained for at least 3 months of CPAP use. A reduction in BP was also observed, even though BP control was not always achieved.