Aortic Knob Width: A Possible Marker of Vascular Remodeling in Obstructive Sleep Apnea

Obstructive sleep apnea -related hypertension: a review of the literature and clinical management strategy

Obstructive Sleep Apnea (OSA) and hypertension have a high rate of co-occurrence, with OSA being a causative factor for hypertension. Sympathetic activity due to intermittent hypoxia and/or fragmented sleep is the most important mechanisms triggering the elevation in blood pressure in OSA. OSA-related hypertension is characterized by resistant hypertension, nocturnal hypertension, abnormal blood pressure variability, and vascular remodeling. In particular, the prevalence of OSA is high in patients with resistant hypertension, and the mechanism proposed includes vascular remodeling due to the exacerbation of arterial stiffness by OSA. Continuous positive airway pressure therapy is effective at lowering blood pressure, however, the magnitude of the decrease in blood pressure is relatively modest, therefore, patients often need to also take antihypertensive medications to achieve optimal blood pressure control. Antihypertensive medications targeting sympathetic pathways or the renin-angiotensin-aldosterone system have theoretical potential in OSA-related hypertension, Therefore, beta-blockers and renin-angiotensin system inhibitors may be effective in the management of OSA-related hypertension, but current evidence is limited. The characteristics of OSA-related hypertension, such as nocturnal hypertension and obesity-related hypertension, suggests potential for angiotensin receptor-neprilysin inhibitor (ARNI), sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucose-dependent insulinotropic polypeptide receptor/ glucagon-like peptide-1 receptor agonist (GIP/GLP-1 RA). Recently, OSA has been considered to be caused not only by upper airway anatomy but also by several non-anatomic mechanisms, such as responsiveness of the upper airway response, ventilatory control instability, and reduced sleep arousal threshold. Elucidating the phenotypic mechanisms of OSA may potentially advance more personalized hypertension treatment strategies in the future. Clinical characteristics and management strategy of OSA-related hypertension. OSA obstructive sleep apnea, BP blood pressure, ABPM ambulatory blood pressure monitoring, CPAP continuous positive airway pressure, LVH left ventricular hypertrophy, ARB: angiotensin II receptor blocker, SGLT2i Sodium-glucose cotransporter 2 inhibitors, ARNI angiotensin receptor-neprilysin inhibitor, CCB calcium channel blocker, GIP/GLP-1 RA glucose-dependent insulinotropic polypeptide receptor and glucagon-like peptide-1 receptor agonist.

Moderate to severe obstructive sleep apnea is independently associated with inter-arm systolic blood pressure difference: Tokyo Sleep Heart Study

OBJECTIVE

Obstructive sleep apnea (OSA) is recognized as an independent risk factor for cardiovascular disease. On the other hand, inter-arm systolic blood pressure difference (IAD), inter-ankle systolic blood pressure difference (IAND), and ankle-brachial index (ABI) are all known predictors of cardiovascular events. The aim of the present study was to investigate the association between OSA and four-limb blood pressure differences.

METHODS

We conducted this cross-sectional study in a large sleep cohort from Tokyo Sleep Heart Study. In 2643 consecutive patients who visited our sleep clinic for polysomnography between 2005 and 2017, all the patients underwent blood pressure measurement simultaneously in all the four limbs by oscillometric methods.

RESULTS

The prevalence rate of IAD ≥10 mmHg was significantly higher in the moderate OSA (15 ≤ apnea-hypopnea index [AHI] < 30) group (4.2%) and severe OSA (AHI ≥ 30) group (4.6%) than that in the no/mild (AHI < 15) OSA group (1.4%). Multivariate logistic regression analysis also identified moderate to severe OSA as being significantly associated with IAD ≥10 mmHg, even after adjustments for confounding variables (moderate OSA: odds ratio [OR], 4.869; 95% confidence interval [CI], 1.080-21.956; P = 0.039; severe OSA: OR, 5.301; 95% CI, 1.226-22.924; P = 0.026). However, there were no significant associations of the OSA severity with IAND ≥15 mmHg or ABI <0.9.

CONCLUSIONS

Moderate to severe OSA was independently associated with the IAD, not but with the IAND or ABI.

miR-126a-3p targets HIF-1α and alleviates obstructive sleep apnea syndrome with hypertension

The obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder and an important cause of refractory hypertension. MicroRNAs (miRNAs) are involved in the development of hypertension, but their role in OSAS with hypertension (OSAS-hypertension) has been little studied. Evidence indicates that miR-126a-3p expression is lower in patients with OSAS-hypertension compared with the patients with OSAS alone. However, its role in the pathogenesis of OSAS-hypertension remains unclear. Therefore, this study aims to investigate the role of miR-126a-3p in OSAS-hypertension and to determine whether HIF-1α is involved in this process. Sprague Dawley rats were exposed to chronic intermittent hypoxia (CIH) for 8 weeks to induce OSAS-hypertension. Rat aortic smooth muscle cells (A7r5) were cultured under hypoxia as an in vitro model. Our results showed that rats exposed to 8 week CIH exhibited decreased miR-126a-3p and increased HIF-1α expression. Furthermore, administration of recombinant adeno-associated virus expressing miR-126a-3p (rAAV-miR-126a) counteracted the CIH-induced systolic blood pressure upregulation, oxidase stress, inflammation, and heart and abdominal aorta vascular remodeling. Moreover, the mechanism was associated with its targeted suppression of HIF-1α. These findings suggest that miR-126a-3p might be a novel potential therapeutic target for the treatment of OSAS-hypertension.