Thammasat University, Rangsit Campus, Paholyothin Rd., Pathum Thani, Thailand 12120, Thailand.
Curr Neurovasc Res. 2017;14(1):65-70. doi: 10.2174/1570159X14666161213122500.
Reduced cerebrovascular reactivity (CVR) was found in patients with recent lacunar infarct. However, its mechanisms were controversial. The breath holding maneuver as a vasodilatory stimulus is clinically useful for an estimation of cerebrovasomotor reactivity in well co-operative patients. Patients with lacunar infarct have no higher cortical dysfunction and remain well co-operation. The breath holding maneuver is feasible and safe to perform in patients with lacunar infarct. Autonomic nervous system regulates systemic vascular activity. Regulation of autonomic function to cerebrovascular reactivity has been reported in the literature. We examined the correlation between autonomic functions with frequency and nonlinear heart rate variability (HRV) and cerebrovascular reactivity in patients with lacunar infarct by application of breath holding maneuver. Fifteen patients with lacunar infarct (8 women, age 65.6 ± 13.61) and 16 healthy controls (11 women, age 27.33 ± 3.85) were continuously monitored at baseline before maneuver (basal phase), during CVR induction (experimental phase) with breath holding maneuver and after maneuver (recovery phase), for arterial blood pressure (ABP), electrocardiography (EKG), mean cerebral blood flow velocity (mCBFV) of middle cerebral arteries (MCA) by transcranial doppler (TCD). The short term-one minute HRV was analyzed from EKG signals for low frequency (LF)/ high frequency (HF) ratio, nonlinear of standard deviation 1 (SD1), standard deviation 2 (SD2), cardiac Sample Entropy (SampEn) and Shannon Entropy. Significant increasing in mCBFV, LF/HF ratio, SD2/SD1, Shannon Entropy and inversely decreasing SampEn during breath holding maneuver compared with baseline were found in both groups (p<0.05). The trend of cerebrovascular reactivity is similar in both groups. However, there were differences of mCBFV, systolic blood pressure (SysBP) in the whole phases (basal, experiment and recovery) between patients and controls (p<0.05). Less scattered signals of SD1 with low value in patient group were illustrated from Poincaré (p<0.05). This indicated less degree of parasympathetic drive in the patients compared to the controls. Moreover, significant positive correlation between systolic bloods pressure and mCBFV in patients suggests impact of autonomic control and cerebral blood flow on the patho-physiological mechanism of vasodilatation, triggered by hypercapnia from breath holding maneuver in patients with lacunar infarct. Reduction of cerebrovascular reactivity in patients with lacunar infarct may relate with decreased parasympathetic activity. Further study is required to demonstrate whether these findings mean mechanisms of lacunar infarct or the effect of hypertensive response.
在近期腔隙性梗死患者中发现脑血管反应性降低（CVR）。然而，其机制仍存在争议。屏气试验作为一种血管扩张刺激，对于评估合作良好的患者的脑血管反应性具有临床意义。腔隙性梗死患者没有更高的皮质功能障碍，仍然具有良好的合作性。屏气试验在腔隙性梗死患者中是可行且安全的。自主神经系统调节全身血管活动。文献报道自主神经功能调节对脑血管反应性的影响。我们通过应用屏气试验，检查了腔隙性梗死患者自主神经功能与频率和非线性心率变异性（HRV）与脑血管反应性之间的相关性。15 例腔隙性梗死患者（8 名女性，年龄 65.6±13.61）和 16 名健康对照者（11 名女性，年龄 27.33±3.85）在屏气试验前（基础期）、屏气试验期间（试验期）和试验后（恢复期）连续监测动脉血压（ABP）、心电图（EKG）、经颅多普勒（TCD）的大脑中动脉平均血流速度（mCBFV）。从 EKG 信号中分析短期（1 分钟）HRV 的低频（LF）/高频（HF）比、标准偏差 1（SD1）、标准偏差 2（SD2）、心脏样本熵（SampEn）和香农熵。与基础期相比，两组在屏气试验期间 mCBFV、LF/HF 比值、SD2/SD1、Shannon 熵均显著增加，SampEn 显著降低（p<0.05）。两组脑血管反应性的趋势相似。然而，患者与对照组在整个阶段（基础期、试验期和恢复期）的 mCBFV、收缩压（SysBP）存在差异（p<0.05）。与对照组相比，患者组的 SD1 信号较为分散，值较低（p<0.05）。这表明与对照组相比，患者的副交感神经驱动程度较低。此外，患者的收缩压与 mCBFV 呈显著正相关，提示自主控制和脑血流对腔隙性梗死患者因屏气引起的高碳酸血症性血管扩张的病理生理机制的影响。腔隙性梗死患者脑血管反应性降低可能与副交感神经活动减少有关。需要进一步的研究来证明这些发现是否意味着腔隙性梗死的机制或高血压反应的影响。
