Nocturnal Continuous Positive Airway Pressure (nCPAP) Decreases High-Sensitivity C-Reactive Protein (hs-CRP) in Obstructive Sleep Apnea-Hypopnea Syndrome

Clinical outcomes and plaque characteristics in patients with coronary artery disease and concomitant sleep-disordered breathing treated by continuous positive airway pressure

BACKGROUND

Sleep-disordered breathing (SDB) is a risk factor for recurrent adverse events in patients with coronary artery disease (CAD). However, the prognosis of continuous positive alveolar pressure (CPAP) treatment for SDB with CAD remains unknown.

METHODS

A total of 281 consecutive patients with stable CAD requiring percutaneous coronary intervention (PCI) were included and classified into three groups according to the concomitance of SDB and CPAP treatment (untreated SDB group, n = 61; CPAP-SDB group, n = 24; and non-SDB group, n = 138). The incidence of major adverse cardiac and cerebrovascular events (MACCEs) within a year after PCI was compared between the three groups. The characteristics of the culprit plaques, including macrophage accumulation, were further assessed using optical coherence tomography.

RESULTS

The incidence of MACCEs was significantly different among the three groups (p = 0.037), with the highest incidence in the untreated-SDB group (22.9%) and 8.3% and 10.1% in the CPAP-SDB and non-SDB groups, respectively. The incidence of MACCEs at 1 year was significantly lower in patients with appropriate CPAP use than that in inadequately treated patients with SDB (0.0 vs. 22.5%, p = 0.048). Macrophage accumulation differed significantly among the three groups, with the highest accumulation in the untreated SDB group.

CONCLUSIONS

CPAP treatment for SDB may be associated with a lower incidence of MACCEs following PCI and a lower prevalence of macrophages in the culprit plaques.

Effect of Obstructive Sleep Apnea and CPAP Treatment on the Bioavailability of Erythrocyte and Plasma Nitric Oxide

INTRODUCTION

Endothelial dysfunction resulting from decreased nitric oxide (NO) bioavailability is an important mechanism that increases cardiovascular risk in subjects with obstructive sleep apnea (OSA). NO is produced by nitric oxide synthase (NOS) in a reaction that converts L-arginine to L-citrulline. Asymmetric-dimethylarginine (ADMA) is created by L-arginine and is a naturally occurring competitive inhibitor of nitric oxide synthase (NOS). The aim of our study was to verify if erythrocytes could play a role in the storage and accumulation of ADMA in OSA patients. The crosstalk between erythrocyte-ADMA, SDMA, L-arginine, and L-citrulline levels and endothelial function was investigated in OSA subjects both at baseline and prospectively following 1-year CPAP (continuous positive airway pressure) treatment.

MATERIAL AND METHODS

A total of 46 subjects with OSA were enrolled in this study and divided into two groups: those with moderate-to-severe OSA and those with mild or no OSA. A physical examination was followed by blood collection for the assessment of biochemical cardiovascular risk factors and the nitric oxide bioavailability parameters both in plasma and erythrocytes. Vasodilative endothelial function was assessed using Laser Doppler Flowmetry (LDF).

RESULTS

No significant changes regarding the NO pathway metabolites were noted apart from the plasma L-citrulline concentration, which was decreased in patients with OSA (26.9 ± 7.4 vs. 33.1 ± 9.4 μM, p < 0.05). The erythrocyte ADMA concentration was lower than in plasma irrespective of the presence of OSA (0.33 ± 0.12 vs. 0.45 ± 0.08 μM in OSA, p < 0.05 and 0.33 ± 0.1 vs. 0.45 ± 0.07 μM in the control, p < 0.05). No significant changes regarding the LDF were found. CPAP treatment did not change the levels of NO metabolites in the erythrocytes.

CONCLUSIONS

The erythrocyte pool of the NO metabolic pathway intermediates does not depend on OSA and its treatment, whereas the erythrocytes could constitute a high-volume buffer in their storage Hence, the results from this prospective study are a step forward in understanding the role of the erythrocyte compartment and the intra-erythrocyte pathways regulating NO bioavailability and paracrine endothelial function in the hypoxia-reoxygenation setting, such as obstructive sleep apnea.

Laryngopharyngeal Reflux in Obstructive Sleep Apnea-Hypopnea Syndrome: An Updated Meta-Analysis

Laryngopharyngeal reflux (LPR) is a common disorder in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). This meta-analysis was carried out to evaluate the LPR prevalence in individuals with OSAHS and to analyze the correlation of LPR positivity with the clinical features of patients with OSAHS. A detailed review of the English and Chinese literature on the occurrence of LPR in patients with OSAHS was performed by employing online search tools such as PubMed, EMBASE, Web of Science, VIP, CNKI, WanFang, etc. Two researchers analyzed the studies for quality according to the STROBE standard checklist. The acquired data were analyzed using Stata 11.0 and R 3.6.1 software. The effect size was estimated and calculated using weighted mean difference (WMD) and correlation coefficients. Moreover, a combined analysis was performed by employing either a random- or fixed-effects model. Ultimately, 27 studies met our inclusion criteria. Our study revealed that the LPR prevalence in OSAHS patients was 49%. We carried out subgroup analyses as per OSAHS severity, ethnicity, and body mass index (BMI). The results suggested that the probability of LPR in European and American patients with OSAHS was higher, and the prevalence of LPR was higher in obese individuals and patients with severe OSAHS. Moreover, apnea-hypopnea index (AHI) and BMI were higher in LPR-positive OSAHS patients than in LPR-negative OSAHS patients, but no significant variation in age was observed in the two groups. Moreover, the reflux symptom index (RSI) scores and the reflux finding score (RFS) exhibited a positive correlation with AHI. The current literature shows a higher incidence of LPR in individuals with OSAHS (49%). The severity of AHI in individuals with OSAHS is associated with the presence of LPR. Patients with OSAHS accompanied by LPR showed higher BMI and AHI as compared to those patients with LPR-negative OSAHS.