PURPOSE Obstructive sleep apnoea (OSA) is a highly prevalent sleep-related breathing disorder associated with hypertension, impaired peripheral vascular function and an increased risk of stroke. Evidence suggests that abnormalities of the cerebral microcirculation, such as capillary rarefication, may be present in these patients. We evaluated whether the presence of hypertension may affect the cerebral capillary architecture and function assessed by Intravoxel Incoherent Motion (IVIM) magnetic resonance imaging (MRI) in patients with continuous positive airway pressure (CPAP)-treated OSA. METHODS Forty-one patients (88% male, mean age 57 ± 10 years) with moderate-to-severe OSA were selected and divided into two groups (normotensive vs. hypertensive). All hypertensive OSA patients were adherent with their antihypertensive medication. Cerebral microvascular structure was assessed in grey (GM) and white matter (WM) using an echo-planar diffusion imaging sequence with 14 different b values. A step-wise IVIM analysis algorithm was applied to compute true diffusion (D), perfusion fraction (f) and pseudo-diffusion (D*) values. Group comparisons were performed with the Wilcoxon-Mann-Whitney-Test. Regression analysis was adjusted for age. RESULTS Diffusion- and perfusion-related indexes in middle-aged OSA normotensive patients were quantified in both tissue types (D [10-3 mm2/s]: GM = 0.83 ± 0.03; WM = 0.72 ± 0.03; f (%) GM = 0.09 ± 0.01; WM = 0.06 ± 0.01; D* [10-3 mm2/s]: GM = 7.72 ± 0.89; WM = 7.38 ± 0.98). In the examined tissue types, hypertension did not result in changes on the estimated MRI IVIM index values. CONCLUSION Based on IVIM analysis, cerebral microvascular structure and function showed no difference between hypertensive and normotensive patients with moderate-to-severe OSA treated with CPAP. Treatment adherence with antihypertensive drug regime and, in turn, controlled hypertension seems not to affect microvascular structure and perfusion of the brain. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02493673.

中文翻译：

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高血压对CPAP治疗阻塞性睡眠呼吸暂停患者脑微血管结构的影响：扩散磁共振成像研究。

目的阻塞性睡眠呼吸暂停（OSA）是一种高度流行的与睡眠相关的呼吸障碍，与高血压，外周血管功能受损和中风风险增加有关。有证据表明，这些患者可能存在脑微循环异常，例如毛细血管稀疏。我们评估了持续存在气道正压（CPAP）治疗的OSA患者中高血压的存在是否会影响脑毛细血管结构和功能（通过Intravoxel不相干运动（IVIM）磁共振成像（MRI）评估）。方法选择中度至重度OSA的41例患者（男性88％，平均年龄57±10岁），分为两组（血压正常vs高血压）。所有高血压OSA患者均坚持服用降压药。使用具有14个不同b值的回波平面扩散成像序列，评估了灰色（GM）和白质（WM）的大脑微血管结构。应用了逐步IVIM分析算法来计算真实扩散（D），灌注分数（f）和伪扩散（D *）值。使用Wilcoxon-Mann-Whitney-Test进行组比较。对年龄进行回归分析。结果在两种组织类型中均定量了中年OSA血压正常患者的与扩散和灌注相关的指数（D [10-3 mm2 / s]：GM = 0.83±0.03; WM = 0.72±0.03; f（％）GM = 0.09±0.01； WM = 0.06±0.01； D * [10-3 mm2 / s]：GM = 7.72±0.89； WM = 7.38±0.98）。在检查的组织类型中，高血压并未导致估计的MRI IVIM指数值发生变化。结论基于IVIM分析，CPAP治疗的中重度OSA高血压患者和正常血压患者的脑微血管结构和功能无差异。使用降压药物治疗依从性，进而控制高血压似乎不会影响微血管结构和大脑灌注。试验注册ClinicalTrials.gov标识符：NCT02493673。