Monash Cardiovascular Research Centre, MonashHeart and Monash University, Department of Medicine, Monash Medical Centre, Melbourne, Australia.
J Hypertens. 2012 Dec;30(12):2395-402. doi: 10.1097/HJH.0b013e328358bee2.
Central blood pressure is a determinant of cardiovascular outcome; however, it can be described by parameters other than systolic and diastolic pressure with central augmentation index (AIx) often utilized. Although generally considered as determined by peripheral pressure wave reflection, not all data are consistent with this interpretation of AIx. We hypothesized that the motion of the heart during systole may influence central pressure waveform morphology, including the AIx.
We studied the carotid pressure waveform, aortic stiffness and endothelial function in 20 healthy young men (full data available in 19). Arterial stiffness was measured by carotid femoral pulse wave velocity (cfPWV), endothelial function by peripheral arterial plethysmography (PAPl) and central blood pressure waveform by carotid applanation tonometry. Basal cardiac motion was assessed with pulsed wave tissue Doppler imaging of the septal mitral annulus.
Carotid AIx decreased after the administration of glyceryl trinitrate by 11.3 ± (sem) 4.6% (P = 0.02); however, time to the inflection point (Ti) did not change. During systolic contraction at both baseline and after glyceryl trinitrate, time to peak annular systolic velocity was directly related to, and always preceded, carotid Ti (R(2) = 0.81; P < 0.01). Carotid Ti and AIx were not related to cfPWV or endothelial function.
In fit young men, rather than only being a consequence of arterial properties Ti, and therefore central AIx, may be substantially determined by left ventricular systolic function. These findings question the interpretation of central AIx as a measure of pressure wave reflection and aortic stiffness and potentially impact its interpretation in diagnosis and treatment of cardiovascular risk.
中心血压是心血管结果的决定因素；然而，它可以通过除收缩压和舒张压以外的参数来描述，其中中心增强指数（AIx）通常被用于描述。虽然通常认为 AIx 由外周压力波反射决定，但并非所有数据都与这种 AIx 解释一致。我们假设心脏在收缩期的运动可能会影响中心血压波形形态，包括 AIx。
我们研究了 20 名健康年轻男性的颈动脉压力波形、主动脉僵硬和内皮功能（完整数据可在 19 名男性中获得）。通过颈动脉-股动脉脉搏波速度（cfPWV）测量动脉僵硬，通过外周动脉体积描记法（PAPl）测量内皮功能，通过颈动脉平板压力测量法测量中心血压波形。通过二尖瓣环间隔组织多普勒成像测量基础心脏运动。
在给予硝酸甘油后，颈动脉 AIx 降低了 11.3 ± 4.6%（P = 0.02）；然而，拐点时间（Ti）没有改变。在基础状态和硝酸甘油给药后收缩期收缩期间，峰值环向收缩速度的时间与颈动脉 Ti 直接相关，并且始终先于颈动脉 Ti（R² = 0.81；P < 0.01）。颈动脉 Ti 和 AIx 与 cfPWV 或内皮功能无关。
在健康的年轻男性中，Ti，以及因此 AIx，可能主要由左心室收缩功能决定，而不仅仅是动脉特性的结果。这些发现质疑了将中心 AIx 作为压力波反射和主动脉僵硬的测量指标的解释，并可能对其在心血管风险诊断和治疗中的解释产生影响。
