The effect of high evening blood pressure on obstructive sleep apnea–related morning blood pressure elevation: does sex modify this interaction effect?

Purpose

Obstructive sleep apnea (OSA) can lead to increased morning blood pressure (BP). We hypothesized that high evening BP may aggravate OSA-related morning BP elevation. Additionally, this interactional effect may be modified by sex.

Methods

This retrospective, cross-sectional study included newly diagnosed OSA patients with an apnea-hypopnea index (AHI) ≥?5 per hour on a full-night polysomnography. An analysis of covariance (ANCOVA) was used to determine whether severe OSA (AHI?≥?30) was associated with higher morning BP than mild-to-moderate OSA (5?≤?AHI?<?30) and whether there was an interaction between apnea severity and evening BP on morning BP. To identify the sex effects, analyses were performed separately in each sex group.

Results

A total of 1445 patients with an average age of 51.9 years (SD 11.7) (male 77.9% vs. female 22.1%; high evening BP group 22.4% vs. normal evening BP group 59.6%) were included in the study. Based on the ANCOVA, patients with severe OSA had significantly higher morning systolic BP (SBP) (p?=?0.003), diastolic BP (DBP) (p?<?0.001), and mean BP (MBP) (p?<?0.001) than the mild-to-moderate group in male subjects. A significant interaction between apnea severity and evening BP was identified on morning DBP and MBP in male subjects. However, there were no differences in morning BP between severe and mild-to-moderate OSA groups in female subjects.

Conclusions

In male subjects, severe OSA contributed to higher morning BP than mild-to-moderate OSA. OSA-associated morning BP elevation was more prominent in the high evening BP group than in the normal BP group. Such relations were not found in female subjects.

     

Inhibition of awake sympathetic nerve activity of heart failure patients with obstructive sleep apnea by nocturnal continuous positive airway pressure

OBJECTIVES: This study was designed to determine whether reductions in morning systolic blood pressure (BP) elicited by treatment of moderate to severe obstructive sleep apnea (OSA) in heart failure (HF) patients are associated with a reduction in sympathetic vasoconstrictor tone. BACKGROUND: Daytime muscle sympathetic nerve activity (MSNA) is elevated in HF patients with coexisting OSA. In our recent randomized trial in HF, abolition of OSA by continuous positive airway pressure (CPAP) increased left ventricular ejection fraction (LVEF) and lowered morning systolic BP. METHODS: Muscle sympathetic nerve activity, BP, and heart rate (HR) of medically treated HF patients (EF <45%) and OSA (apnea-hypopnea index > or =20/h of sleep) were recorded on the morning after overnight polysomnography, and again one month after patients were randomly allocated nocturnal CPAP treatment or no CPAP (control). RESULTS: In nine control patients, there were no significant changes in the severity of OSA, MSNA, systolic BP, or HR. In contrast, in the 8 CPAP-treated patients, OSA was attenuated, and there were significant reductions in daytime MSNA (from 58 +/- 4 bursts/min to 48 +/- 5 bursts/min; 84 +/- 4 bursts/100 heart beats to 72 +/- 5 bursts/100 heart beats; p < 0.001 and p = 0.003, respectively), systolic BP (from 135 +/- 5 mm Hg to 120 +/- 6 mm Hg, p = 0.03), and HR (from 69 +/- 2 min(-1) to 66 +/- 2 min(-1); p = 0.013). CONCLUSIONS: Treatment of coexisting OSA by CPAP in HF patients lowers daytime MSNA, systolic BP, and HR. Inhibition of increased central sympathetic vasoconstrictor outflow is one mechanism by which nocturnal CPAP reduces awake BP in HF patients with moderate to severe OSA.     

Long-term effect of continuous positive airway pressure on BP in patients with hypertension and sleep apnea

OBJECTIVE: To analyze the long-term effect of continuous positive airway pressure (CPAP) on ambulatory BP in patients with obstructive sleep apnea (OSA) and hypertension, and to identify subgroups of patients for whom CPAP could be more effective. METHODS: We conducted a prospective, long-term follow-up trial (24 months) in 55 patients with OSA and hypertension (mean CPAP use, 5.3 +/- 1.9 h/d [+/- SD]). Twenty-four-hour ambulatory BP monitoring (ABPM) was measured at baseline and after intervention with CPAP on an intention-to-treat basis. In addition, the correlation between the changes in 24-h mean arterial pressure (24hMAP) and CPAP compliance, OSA severity, and baseline ABPM was assessed. RESULTS: At the end of follow-up, a significant decrease was shown only in diastolic BP (- 2.2 mm Hg; 95% confidence interval [CI], - 4.2 to - 0.1; p = 0.03) but not in 24hMAP or other ABPM parameters. However, a correlation between changes in 24hMAP and baseline systolic BP (r = - 0.43, p = 0.001), diastolic BP (r = - 0.38, p = 0.004), and hours of use of CPAP (r = - 0.30, p = 0.02) was observed. A significant decrease in the 24hMAP was achieved in a subgroup of patients with incompletely controlled hypertension at entry (- 4.4 mm Hg; 95% CI, - 7.9 to - 0.9 mm Hg; p = 0.01), as well as in those with CPAP compliance > 5.3 h/d (- 5.3 mm Hg; 95% CI, - 9.5 to - 1.2 mm Hg; p = 0.01). Linear regression analysis showed that baseline systolic BP and hours of CPAP were independent predictors of reductions in BP with CPAP. CONCLUSION: Long-term CPAP reduced BP modestly in the whole sample. However, patients with higher BP at entry and good CPAP compliance achieved significant reductions in BP.     

Efficacy of nasal masks versus nasal pillows masks during continuous positive airway pressure titration for patients with obstructive sleep apnea

Purpose

Nasal masks are usually the first choice for CPAP therapy, but patients may experience side effects. There are limited data regarding the efficacy of nasal pillows masks during CPAP titration. This study aimed to compare the polysomnography outcomes during CPAP titration while comparing two types of masks (nasal and pillows) and to assess whether or not the patient characteristics differed between mask preferences.

Methods

In a sleep-disorders clinic, we prospectively analyzed all patients undergoing CPAP titration for three consecutive months. CPAP pressures were manually titrated. Anthropometric data (age, sex, body mass index, and neck and waist circumferences) and OSA severity were documented. Patients completed a self-administered questionnaire that measured nasal obstruction (NOSE scale). Before titration, both types of masks were presented to patients, and each of them chose the one they preferred.

Results

Of 157 patients, 55% (n = 86) used nasal masks, and 45% (n = 71) used nasal pillows masks. There was no difference according to mask type chosen by age, sex, body mass index, neck and waist circumferences, and NOSE scale. Polysomnography outcomes were similar between the mask groups. The mean CPAP level was 9.4 ± 1.8 cm H₂O for nasal masks and 9.1 ± 2.0 cm H₂O for nasal pillows (p = 0.61). Residual apnea-hypopnea index was 3.0 ± 2.8 events/h for nasal mask and 3.5 ± 4.1 events/h for pillow mask (p = 0.28). Baseline AHI, body mass index, neck and waist circumferences, and residual AHI were independent predictors of a higher CPAP pressure for both groups (p < 0.0001).

Conclusions

Nasal pillows masks seem to be as effective as nasal masks and may be considered to be an initial choice for CPAP titration.

     

Impact of Continuous Positive Airway Pressure Therapy on Blood Pressure in Patients with Obstructive Sleep Apnea Hypopnea: A Meta-analysis of Randomized Controlled Trials

Patients with untreated obstructive sleep apnea hypopnea (OSAH) are predisposed to developing hypertension, and therapy with continuous positive airway pressure (CPAP) may reduce blood pressure (BP). The purpose of this study was to assess the impact of CPAP therapy on BP in patients with OSAH. We performed a comprehensive literature search up to July 2006 [Medline, PubMed, EMBASE, Cochrane Database of Systematic Reviews (CDSR), Cochrane controlled trials register (CCTR), and Database of Abstract and Reviews of Effect (DARE)] to identify clinical studies and systemic reviews that examined the impact of CPAP on BP. Studies were included if they (1) were randomized controlled trials with an appropriate control group, (2) included systolic and diastolic BP measurements before and after CPAP/control in patients with OSAH, and (3) contained adequate data to perform a meta-analysis. To calculate pooled results, studies were weighted by inverse variances, with either a fixed or a random effects model used depending on the presence of heterogeneity (assessed with Q test). Ten studies met our inclusion criteria (587 patients): three studies were crossover (149 patients) and seven were parallel in design. Seven studies (421 patients) used 24-h ambulatory BP and three used one-time measurements. Two studies were of patients with heart failure (41 patients). Overall, the effects of CPAP were modest and not statistically significant; CPAP (compared to control) reduced systolic BP (SBP) by 1.38 mmHg (95% CI: 3.6 to −0.88, p = 0.23) and diastolic BP (DBP) by 1.52 mmHg (CI: 3.1 to −0.07; p = 0.06). Six of the trials studied more severe OSAH (mean AHI > 30/h, 313 patients); in these six trials, CPAP reduced SBP by 3.03 mmHg (CI 6.7 to −0.61; p = 0.10) and DBP by 2.03 mmHg (CI: 4.1 to −0.002; p = 0.05). There was a trend for SBP reduction to be associated with CPAP compliance. In unselected patients with sleep apnea, CPAP has very modest effects on BP. However, we cannot exclude the possibility that certain subgroups of patients may have more robust responses—this may include patients with more severe OSAH or difficult-to-control hypertension. Future randomized controlled trials in this area should potentially concentrate on these subgroups of patients. Dr. Ayas has received research funding from Respironics Inc., a maker of CPAP equipment.     

Pressure adjustment is the most useful intervention for improving compliance in telemonitored patients treated with CPAP in the first 6 months of treatment

Purpose

Telemonitoring (TMg) for patients treated with continuous positive airway pressure (CPAP) is now routine care in some sleep labs. The purpose of the present study was to identify technical interventions associated with improved CPAP compliance in a real-life cohort of newly telemonitored patients with obstructive sleep apnea (OSA) during the first 6 months of treatment.

Methods

All patients with moderate-to-severe OSA (apnea-hypopnea index (AHI) ≥ 15/h) who were newly treated with CPAP were included in the study and telemonitored. A group educational session was scheduled after 1 month. Technical interventions were performed at the patient’s request and during scheduled visits and the impact of each intervention on CPAP therapy compliance was collected.

Results

Between May 2018 and Dec 2019, 349 patients newly diagnosed with OSA were hospitalized in the sleep lab for CPAP titration and 212 patients were included (mean age 54.6 ± 13.1 years, mean BMI 31.7 ± 5.8 kg/m², mean AHI 42.8 ± 22.0). TMg acceptance rate was 87%. Mean 6-month compliance was 275 ± 154 min, 13% stopped CPAP, and 17% were non-compliant. Correlations were observed between BMI (r = 0.15, p = 0.029), median and 95th percentile leaks (r = ?0.23 and ?0.18, p = 0.016 and 0.002), and CPAP compliance.

During follow-up, 92 interventions were required, mainly for mask change (n = 80). Pressure modification (n = 16) was the only intervention that increased CPAP use > 30 min/night, p = 0.021.

Conclusion

Pressure modification was the only adaptation that significantly increased CPAP compliance during the first 6 months. Remote TMg allows providing daily, accurate, and immediate feedback that could help clinicians to confirm that the CPAP treatment is effective.

     

Abnormal vasoactive hormones and 24-hour blood pressure in obstructive sleep apnea

BACKGROUND: Patients with obstructive sleep apnea (OSA) are at increased risk for hypertension. The mechanisms responsible for the development of hypertension are controversial. We hypothesized that patients with OSA had an abnormal 24-h blood pressure (BP) and an abnormal activity in vasoactive hormones, and that both BP and hormones were normalized during treatment with long-term nasal continuous positive airway pressure (CPAP). METHODS: The 24-h BP and plasma levels of the vasoactive hormones (renin, angiotensin II, aldosterone, atrial natriuretic peptide, brain natriuretic peptide, vasopressin, and endothelin-1) were measured in 24 patients with OSA and in 18 control subjects. Thirteen patients with OSA were reexamined after 14 months of CPAP therapy. RESULTS: Patients with OSA had significantly increased BP and heart rate and a reduced nocturnal BP drop. Both angiotensin II (13.3 +/- 1.6 v 7.8 +/- 1.0 pmol/L) and aldosterone (94.0 +/- 9.4 v 62.2 +/- 4.5 pmol/L) were significantly higher in OSA than in control subjects. Positive correlations were found between angiotensin II and daytime BP (systolic: r = 0.49, P <.01; diastolic: r = 0.52, P <.01). The CPAP therapy resulted in a decrease in BP, and this CPAP-induced reduction in BP was correlated with a decrease in both plasma renin (r = 0.76 to 0.92, all P <.01) and plasma angiotensin II concentration (r = 0.58 to 0.81, all P <.05). CONCLUSIONS: Plasma angiotensin II and aldosterone were elevated in OSA, and plasma angiotensin II was correlated with BP. Long-term CPAP reduced BP, and this decrease in BP was correlated with the reductions in plasma renin and angiotensin II levels. We suggest that OSA mediates hypertension, at least in part, via a stimulation of angiotensin II production.     

Impact of CPAP treatment for obstructive sleep apnea on visceral adipose tissue: a meta-analysis of randomized controlled trials

Background

It is still controversial if the continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnea (OSA) can markedly influence an effect on visceral adipose tissue (VAT). The current study aimed to assess the efficacy of CPAP interventions in reducing VAT in OSA patients.

Methods

The Web of Science, PubMed, Embase, and Cochrane Library (up to December, 2019) were searched for randomized trials that assessed the effect of CPAP therapy in decreasing VAT in OSA patients. Information on the study, pre- and post-CPAP treatment of VAT, and patient characteristics were extracted for analysis. The standardized mean difference (SMD) was applied to measure the summary estimates. The analysis was conducted with STATA 13.0 and RevMan v.5.3.

Results

Five studies (6 cohorts) that involved 169 patients were enrolled in the meta-analysis. There was no significant change of VAT in patients with OSA before and after CPAP treatment (SMD = ? 0.00, 95% CI = ? 0.21 to 0.21, z = 0.01, p = 0.99). Subgroup analyses further demonstrated that the results were not influenced by CPAP therapy duration, patient age, sample size, or baseline body mass index.

Conclusions

Among the patients with OSA, our meta-analysis revealed that treatment with CPAP does not significantly lead to a reduction of VAT. High-quality randomized controlled trials may provide further clarifying information.

     

Refractory hypertension and sleep apnoea: effect of CPAP on blood pressure and baroreflex.

This study was undertaken to determine whether abolition of obstructive sleep apnoea (OSA) by continuous positive airway pressure (CPAP) could reduce blood pressure (BP) in patients with refractory hypertension. In 11 refractory hypertensive patients with OSA, the acute effects of CPAP on nocturnal BP were studied during sleep and its longer term effects on 24-h ambulatory BP after 2 months. During a single night's application, CPAP abolished OSA and reduced systolic BP in stage 2 sleep from 138.3 +/- 6.8 to 126.0 +/- 6.3 mmHg. There was also a trend towards a reduction in average diastolic BP (from 77.7 +/- 4.5 to 72.9 +/- 4.5). CPAP usage for 2 months was accompanied by an 11.0 +/- 4.4 mmHg reduction in 24-h systolic BP. In addition, both the nocturnal and daytime components of systolic BP fell significantly by 14.4 +/- 4.4 and 9.3 +/- 3.9 mmHg, respectively. Diastolic BP was reduced significantly at night by 7.8 +/- 3.0 mmHg. In patients with refractory hypertension, acute abolition of obstructive sleep apnoea by continuous positive airway pressure reduces nocturnal blood pressure. These data also suggest that continuous positive airway pressure may reduce nocturnal and daytime systolic blood pressure chronically. Randomised trials are needed to confirm the latter results.     

Variables affecting the change in systemic blood pressure in response to nasal CPAP in obstructive sleep apnea patients

We hypothesized that an improvement in systemic blood pressure (BP) during continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea (OSA) would be related to severity of hypertension (HTN), morphometric parameters such as body mass index, and level of CPAP adherence. We tested this hypothesis with a retrospective review of 85 consecutive OSA patients who had completed diagnostic and CPAP titration polysomnograms and were equipped with a CPAP-adherence monitoring system for a minimum of 1 month of observation. Sphygmomanometer-obtained BP readings were compared at baseline and after 4–6 weeks of CPAP therapy. Presentation BP was significantly and strongly associated with the change in BP seen with treatment. Those with an elevated systolic and diastolic BP and those with an elevation of either systolic or diastolic BP showed a significant fall in BP on CPAP. Those with a BP below the hypertensive range of 140/90 on presentation did not have a significant drop in BP with CPAP. There were no significant changes in systolic, diastolic, or mean BP when patients were categorized by the severity of HTN, as determined by the number of antihypertensive medications prescribed or if they were categorized by the degree of CPAP adherence, objectively determined by the average use of more or less than 4 h/night. We conclude that HTN at initial presentation is among the most important indicators of potential benefit of CPAP administration on BP.     

Effect of oral appliance therapy on blood pressure in Japanese patients with obstructive sleep apnea

Objective: Obstructive sleep apnea (OSA) treatment in patients with OSA and hypertension reduces blood pressure (BP). Oral appliance (OA) therapy is nowadays prescribed for patients with mild to moderate OSA. This study aimed to clarify the effect of OA therapy on BP reduction in Japanese patients with mild to moderate OSA. Methods: Polysomnography was employed to detect sleep-disordered breathing. Totally, 237 patients without cardiac and/or cerebrovascular diseases and those with apnea-hypopnea index (AHI) ≥ 5/h–< 30/h were enrolled. Office BP change after receiving 8–12 weeks of OA therapy was assessed and the factors related to the degree of BP reduction were analyzed. Results: The study patients consisted of 188 men and 49 women, the mean age was 54.7 ± 13.2 years old, and the body mass index (BMI) was 24.6 ± 3.4 kg/m². The antihypertensive effect of OA therapy resulted in systolic BP (SBP) ?2.4 ± 14.8 (p = 0.078) and diastolic BP (DBP) ?2.0 ± 11.7 mm Hg (p = 0.045) in all patients. SBP before OA therapy played a significant role in the degree of SBP reduction (β = ?0.597, p < 0.001), whereas DBP before OA therapy was a significant factor of the degree of DBP reduction (β = ?0.522, p < 0.001). Conclusion: A certain time period of OA therapy effected BP reduction in mild to moderate OSA patients without cardiac and/or cerebrovascular diseases. Its antihypertensive effect was greater in OSA patients whose BP was higher before receiving OA therapy.     

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.

     

Evening-morning differences in blood pressure in sleep apnea syndrome: effect of gender

BACKGROUND: Obstructive sleep apnea (OSA) is associated with hypertension. In the current study we sought to determine whether the evening-morning differences in blood pressure (BP) would correlate with the severity of OSA and whether there are gender-related differences. METHODS: A total of 2009 consecutive patients referred to sleep examination because of suspected sleep apnea were retrospectively included. The patients comprised 1566 men, of whom 870 were nonhypertensive (non-HT) and 696 hypertensive (HT) and 443 women, of whom 258 were non-HT and 185 HT. Four BP measurements, two in the evening and two in the morning, were taken. The relationship between evening-morning differences in BP and the number of apneas/hypopneas divided by hours of sleep (AHI) were analyzed separately for HT and non-HT men and women. RESULTS: In men, increase in AHI was associated with increase in morning BP, and the evening-morning difference for both systolic and diastolic BP became negative. These trends were found to be significant by linear regression analyses both for HT (for systolic BP, r = 0.75, P < .05, for diastolic BP r = 0.96, P < .05) and non-HT patients (for systolic BP r = 0.93, P < .05, for diastolic BP r = 0.94, P < .05). In women (unlike in men), increasing AHI was not associated with a linear increase in the evening-morning BP differences. None of the regression lines fitted to the data was significant. CONCLUSIONS: Our results demonstrate that the evening to morning difference in BP in men with OSA is linearly related to the severity of OSA, both in patients with HT and in those with non-HT. These results may have practical relevance in screening for patients with OSA and may have prognostic clinical value in predicting future cardiovascular events.     

Continuous Positive Airway Pressure in Patients With Obstructive Sleep Apnea and Resistant Hypertension: A Meta‐Analysis of Randomized Controlled Trials

This study aimed to analyze the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) in patients with obstructive sleep apnea (OSA) and resistant hypertension. Randomized controlled trials (RCTs) that evaluated the effect of CPAP on BP in patients with OSA and resistant hypertension, indexed in MEDLINE, Embase, and the Cochrane Library from inception until March 20, 2015, were included in the meta‐analysis. A total of five RCTs were identified to meet the inclusion criteria. The pooled changes after CPAP treatment for 24‐hour ambulatory systolic BP and diastolic BP (DBP) were −4.78 mm Hg (95% confidence interval [CI], −7.95 to −1.61) and −2.95 mm Hg (95% CI, −5.37 to −0.53) in favor of the CPAP group. CPAP was also associated with reduction in nocturnal DBP (mean difference, −1.53 mm Hg, 95% CI, −3.07 to 0). The results indicated a favorable reduction in BP with CPAP treatment in patients with OSA and resistant hypertension.     

Effectiveness of using long-acting angiotensin II type 1 receptor blocker in Japanese obese patients with metabolic syndrome on morning hypertension monitoring by using telemedicine system (FUJIYAMA Study)

Aim: Recently, obesity patients have been diagnosed as metabolic syndrome. The aim of this study was to evaluate which angiotensin type 1 receptor blockers (ARBs), telmisartan or candesartan, is superior for the control of home blood pressure (BP) in the morning when the outpatient clinic BP was well controlled in the patients with metabolic syndrome.

Methods: The patients with metabolic syndrome were enrolled. Home BP was monitored by using a telemedicine system. After a 2- to 4-week control period to establish baseline home BP values, these patients were randomly divided into telmisartan (20–80?mg) and candesartan (4–12?mg) groups. These end points were evaluated by using the telemedicine system during steady-state active therapy. A total of 356 patients attending 60 outpatient Japanese centers were recruited.

Results: On a day of active therapy, telmisartan significantly lowered both systolic and diastolic home BP in the morning to a greater extent compared to candesartan. At the end of the study, reductions in systolic and diastolic home BP in the morning, in telmisartan group were significantly larger compared to the changes in the candesartan group (systolic; Tel: 12.0?±?8.9 versus Can: 8.1?±?17.1?mmHg, p?=?0.0292, diastolic; Tel: 7.4?±?6.1 versus Can: 3.7?±?6.8?mmHg, p?=?0.0053). Additionally in the telmisartan treated group, LDL-cholesterol showed significant reduction (p?=?0.037), but candesartan did not.

Conclusion: The present study by using the telemedicine system clearly demonstrated that telmisartan has a strong effect on reducing morning home BP, and a good effect on lipid metabolism in patients with metabolic syndrome.     

The velocity of home blood pressure reduction in response to low-dose eplerenone combined with other antihypertensive drugs determined by exponential decay function analysis

Background/objective: Eplerenone is a highly selective aldosterone blocker, which has the potential to lower blood pressure (BP) in patients with hypertension. The objective of this study was to assess the hypotensive effects of low-dose eplerenone (25?mg) using home BP measurements. We also assessed the time required to reach 95% of the maximum antihypertensive effect (stabilization time) by analyzing exponential decay functions using home BP measurements.

Methods: We reviewed the medical records of 83 hypertensive patients who were taking eplerenone 25?mg (age, 68.6?±?11.8?years; men, 36.1%) in addition to other antihypertensive agents. Home BPs were averaged in each patient for the last 5?days of each observation period. The morning versus evening effect (M/E ratio) and the evening versus morning effect (E/M ratio) were calculated to assess the duration of action of eplerenone.

Results: The mean home systolic/diastolic BPs at baseline were 136.8?±?8.8/77.2?±?9.3?mmHg, respectively. After 8?weeks of treatment with eplerenone, home systolic/diastolic BP significantly decreased by ?7.1?±?10.1/?2.6?±?5.0?mmHg (p?p?=?0.006) and 16.5 days (p?=?0.001), respectively. When eplerenone was administered in the morning, the M/E ratio was 1.1?±?0.3. The corresponding E/M ratio for evening administration was 0.9?±?0.6. Although no nocturia was observed, there was a slight but significant increase in serum potassium levels (p?=?0.03).

Conclusions: Our data suggest that the combination of eplerenone with other antihypertensive drugs may be a promising therapeutic strategy for the treatment of essential hypertension.     

Impact of continuous positive airway pressure on vascular endothelial growth factor in patients with obstructive sleep apnea: a meta-analysis

Purpose

Cumulative evidence supports the clear relationship of obstructive sleep apnea (OSA) with cardiovascular disease (CVD). And, adherence to continuous positive airway pressure (CPAP) treatment alleviates the risk of CVD in subjects with OSA. Vascular endothelial growth factor (VEGF), a potent angiogenic cytokine regulated by hypoxia-inducible factor, stimulates the progression of CVD. Thus, whether treatment with CPAP can actually decrease VEGF in patients with OSA remains inconclusive. The purpose of the present study was to quantitatively evaluate the impact of CPAP therapy on VEGF levels in OSA patients.

Methods

We systematically searched Web of Science, Cochrane Library, PubMed, and Embase databases that examined the impact of CPAP on VEGF levels in OSA patients prior to May 1, 2017. Related searching terms were “sleep apnea, obstructive,” “sleep disordered breathing,” “continuous positive airway pressure,” “positive airway pressure,” and “vascular endothelial growth factor.” We used standardized mean difference (SMD) to analyze the summary estimates for CPAP therapy.

Results

Six studies involving 392 patients were eligible for the meta-analysis. Meta-analysis of the pooled effect showed that levels of VEGF were significantly decreased in patients with OSA before and after CPAP treatment (SMD?=???0.440, 95% confidence interval (CI)?=???0.684 to ??0.196, z?=?3.53, p?=?0.000). Further, results demonstrated that differences in age, body mass index, apnea–hypopnea index, CPAP therapy duration, sample size, and racial differences also affected CPAP efficacy.

Conclusions

Improved endothelial function measured by VEGF may be associated with CPAP therapy in OSA patients. The use of VEGF levels may be clinically important in evaluating CVD for OSA patients. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

     

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.     

Association between sleep apnea severity and blood coagulability: treatment effects of nasal continuous positive airway pressure

A prothrombotic state may contribute to the elevated cardiovascular risk in patients with obstructive sleep apnea (OSA). We investigated the relationship between apnea severity and hemostasis factors and effect of continuous positive airway pressure (CPAP) treatment on hemostatic activity. We performed full overnight polysomnography in 44 OSA patients (mean age 47±10 years), yielding apnea–hypopnea index (AHI) and mean nighttime oxyhemoglobin saturation (SpO₂) as indices of apnea severity. For treatment, subjects were double-blind randomized to 2 weeks of either therapeutic CPAP (n=18), 3 l/min supplemental nocturnal oxygen (n=16) or placebo–CPAP (<1 cm H₂O) (n=10). Levels of von Willebrand factor antigen (VWF:Ag), soluble tissue factor (sTF), D-dimer, and plasminogen activator inhibitor (PAI)-1 antigen were measured in plasma pre- and posttreatment. Before treatment, PAI-1 was significantly correlated with AHI (r=0.47, p=0.001) and mean nighttime SpO₂ (r=−0.32, p=0.035), but these OSA measures were not significantly related with VWF:Ag, sTF, and D-dimer. AHI was a significant predictor of PAI-1 (R ²=0.219, standardized β=0.47, p=0.001), independent of mean nighttime SpO2, body mass index (BMI), and age. A weak time-by-treatment interaction for PAI-1 was observed (p=0.041), even after adjusting for age, BMI, pre-treatment AHI, and mean SpO₂ (p=0.046). Post hoc analyses suggested that only CPAP treatment was associated with a decrease in PAI-1 (p=0.039); there were no changes in VWF:Ag, sTF, and D-dimer associated with treatment with placebo–CPAP or with nocturnal oxygen. Apnea severity may be associated with impairment in the fibrinolytic capacity. To the extent that our sample size was limited, the observation that CPAP treatment led to a decrease in PAI-1 in OSA must be regarded as tentative.     

Long-term nasal CPAP does not ameliorate obstructive sleep apnoea

Fifty-seven patients with obstructive sleep apnoea (OSA) were treated for at least six months with nasal continuous positive airway pressure (CPAP). At follow-up, sleep studies were performed in which CPAP was not used for the first half of the night. We compared the severity of OSA at follow-up without CPAP to the severity of OSA during the patient's initial diagnostic study. Apnoea and hypopnoea index (AHI) fell from 41.4 ± 7.5 (mean ±95% CI) to 34.8 ± 7.9 (p= 0.06 by Wilcoxon test) and minimum oxygen saturation rose from 71.6 ± 3.2 to 78.5 ± 2.6 (p<0.001). Some of this change may have been due to reduced REM sleep in the follow-up study (10.5±2.1% Total Sleep Time vs 7.4±2.4% TST, p<0.05). Long-term nasal CPAP was not associated with any reduction of obesity (BMI before CPAP 31.9 ± 1.0, after CPAP 31.7 ± 1.0 (p= 0.39). Systolic arterial pressure fell (before CPAP 143.0 ±4.5 mmHg, after CPAP 136.3 ± 4.6, p < 0.05) but diastolic pressure did not (before CPAP 88.5 ± 3.0 mmHg, after CPAP 85.6 ±2.9 mmHg, p = 0.11). We concluded that the effect of CPAP treatment for six or more months was a small fall in AHI and a small rise in minimum Sa0₂, but that this would be of marginal clinical significance, and may be artefactual. (Aust NZ J Med 1991; 21: 235–238.)