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 subjects underwent blood pressure measurement simultaneously in all the four limbs by oscillometric methods.
Results:
The prevalence rate of IAD ≥ 10 mm Hg was significantly higher in the severe OSA (apnea-hypopnea index ≥ 30) group (4.6%) than in the no/mild (apnea-hypopnea index < 15) OSA group (1.6%). Multivariate logistic regression analysis also identified moderate to severe OSA as being significantly associated with IAD ≥ 10 mm Hg, even after adjustments for confounding variables [moderate OSA; odds ratio (OR): 3.627, 95% confidence interval (CI): 1.056-12.465,
P
= 0.041. Severe OSA; OR: 3.778, 95% CI: 1.113-12.595,
P
= 0.031]. However, there were no significant associations of the OSA severity with IAND ≥ 15 mm Hg or ABI < 0.9.
Conclusions:
Moderate to severe OSA was independently associated with the IAD, not but with the IAND or ABI. The plausible explanation is that the negative intrathoracic pressure caused by OSA may exert an adverse impact on the structural properties of the thoracic aorta. Our findings emphasized that physicians should be careful of IAD, easily applied clinical tool, to evaluate subclinical cardiovascular damage and cardiovascular risk in patients with OSA.