Aortic Stiffness Determines Diastolic Blood Flow Reversal in the Descending Thoracic Aorta: Potential Implication for Retrograde Embolic Stroke in Hypertension
Aortic Stiffness Determines Diastolic Blood Flow Reversal in the Descending Thoracic Aorta: Potential Implication for Retrograde Embolic Stroke in Hypertension
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DOI：
10.1161/hypertensionaha.113.01318
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发表时间：
2013-09-01
期刊：
影响因子：
8.3
通讯作者：
Ito, Sadayoshi
中科院分区：
文献类型：
--
作者：
Hashimoto, Junichiro;Ito, Sadayoshi
主动脉硬化通常先于心血管疾病（包括中风），但潜在的病理生理机制仍然不清楚。我们推测这种异常可能是由于中枢血流动力学改变。对296例无合并症高血压患者，分别记录降主动脉近端和颈动脉多普勒速度脉冲波形，计算逆/前向血流比值和舒张期/收缩期血流指数。在桡动脉上记录张力波形，以估计主动脉压和特征阻抗（Z（0）），并确定颈动脉-股动脉（主动脉）和颈动脉-桡动脉（外周）脉搏波速度。在所有受试者中，主动脉血流波形是双向的，包括收缩期正向和舒张期反向血流。主动脉反向/正向血流比（35 +/- 10%）与主动脉僵硬度参数（包括脉搏波速度、Z（0）和主动脉/外周脉搏波速度比）呈正相关，与年龄、体重指数、主动脉直径和主动脉压无关。颈动脉血流波形呈单向双峰型，收缩期和舒张期峰值最大。颈动脉舒张期/收缩期血流指数（28 +/- 9%）与主动脉反向/正向血流比之间存在正相关关系，在调整主动脉僵硬度和其他相关参数后，该关系仍显着。Bland-Altman图显示主动脉反向和颈动脉舒张期血流峰值之间的时间对应关系密切。总之，主动脉僵硬度决定了降主动脉到主动脉弓的血流逆转程度，这有助于舒张期血流顺行进入颈动脉。这种血流动力学关系构成了高血压患者主动脉僵硬度增加、血流动力学改变和卒中风险增加的潜在机制。
Aortic stiffening often precedes cardiovascular diseases, including stroke, but the underlying pathophysiological mechanisms remain obscure. We hypothesized that such abnormalities could be attributable to altered central blood flow dynamics. In 296 patients with uncomplicated hypertension, Doppler velocity pulse waveforms were recorded at the proximal descending aorta and carotid artery to calculate the reverse/forward flow ratio and diastolic/systolic flow index, respectively. Tonometric waveforms were recorded on the radial artery to estimate aortic pressure and characteristic impedance (Z(0)) and to determine carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities. In all subjects, the aortic flow waveform was bidirectional, comprising systolic forward and diastolic reverse flows. The aortic reverse/forward flow ratio (35 +/- 10%) was positively associated with parameters of aortic stiffness (including pulse wave velocity, Z(0), and aortic/peripheral pulse wave velocity ratio), independent of age, body mass index, aortic diameter, and aortic pressure. The carotid flow waveform was unidirectional and bimodal with systolic and diastolic maximal peaks. There was a positive relationship between the carotid diastolic/systolic flow index (28 +/- 9%) and aortic reverse/forward flow ratio, which remained significant after adjustment for aortic stiffness and other related parameters. The Bland-Altman plots showed a close time correspondence between aortic reverse and carotid diastolic flow peaks. In conclusion, aortic stiffness determines the extent of flow reversal from the descending aorta to the aortic arch, which contributes to the diastolic antegrade flow into the carotid artery. This hemodynamic relationship constitutes a potential mechanism linking increased aortic stiffness, altered flow dynamics, and increased stroke risk in hypertension.