Lund-Johansen P
University of Bergen School of Medicine, Norway.
Curr Opin Cardiol. 1994 Sep;9(5):505-11. doi: 10.1097/00001573-199409000-00002.
For more than 30 years there has been general agreement that in the established phase of essential hypertension, the cardinal hemodynamic disturbance is an increased total peripheral resistance with cardiac output normal during rest, but subnormal during exercise. However, there are still different opinions about the hemodynamics in the starting phase of essential hypertension. Several studies from 1993--mainly performed in the offspring of hypertensive parents--reported high as well as low cardiac index values, depending on the patient selection and the methods used. Irrespective of whether the early phase of essential hypertension is caused primarily by increased cardiac output or increased total peripheral resistance, an increased sympathetic activity is usually held responsible for either hemodynamic disturbance. Simultaneous recordings of central and regional hemodynamics and sympathetic nerve traffic in young subjects with mild hypertension did show increased cardiac output, reduced calf blood flow, and increased nerve traffic as the characteristic features. However, recent studies in subjects with borderline hypertension have shown that if the subjects were aware of having hypertension, they showed higher blood pressure and higher reactivity to mental stress and cold-pressor tests than uninformed subjects with similar blood pressures. With respect to regional circulation, studies have shown that the coronary reserve is reduced in early hypertension, and also in subjects without left ventricular hypertrophy. The role of the endothelium in the regulation of blood flow has attracted great interest. Abnormalities in the production of vasoconstricting and vasodilating substances from the endothelial cells may be at least partially responsible for the increased vascular resistance characteristic of essential hypertension.
30多年来，人们普遍认为，在原发性高血压的发病期，主要的血液动力学紊乱是总外周阻力增加，静息时心输出量正常，但运动时低于正常水平。然而，对于原发性高血压起始阶段的血液动力学仍存在不同观点。1993年的几项研究——主要在高血压患者的后代中进行——根据患者选择和所用方法，报告了高心指数值和低心指数值。无论原发性高血压的早期阶段主要是由心输出量增加还是总外周阻力增加引起，交感神经活动增加通常被认为是导致这两种血液动力学紊乱的原因。对轻度高血压年轻受试者的中心和局部血液动力学以及交感神经活动的同步记录确实显示，心输出量增加、小腿血流量减少和神经活动增加是其特征。然而，最近对临界高血压受试者的研究表明，如果受试者意识到自己患有高血压，他们比血压相似但未被告知的受试者表现出更高的血压以及对精神压力和冷加压试验更高的反应性。关于局部循环，研究表明，早期高血压患者以及无左心室肥厚的受试者的冠状动脉储备均降低。内皮在血流调节中的作用引起了极大关注。内皮细胞产生的血管收缩和舒张物质异常可能至少部分导致了原发性高血压特有的血管阻力增加。
