Vascular function: a key player in hypertension

The major functions of the arterial system are to "efficiently deliver blood to the peripheral organs and maintain vascular homeostasis". Both the endothelial and medial layer contribute to the three major functions, namely, conversion of pulsatile to steady blood flow, appropriate distribution of blood flow to the target organs, and vascular protection and homeostasis. Vascular dysfunction contributes to the development of cardiovascular diseases through a combination of several mechanisms, including impaired coronary perfusion, cardiac systolic/diastolic dysfunction, microvascular damage, and abnormal hemodynamics in the arterial tree. The representative marker of endothelial function is flow-mediated vasodilatation and that of the medial layer function is pulse wave velocity, and that of the blood supply function of the arterial tree is the ankle-brachial pressure index. In hypertension, vascular dysfunction could also lead to the development of isolated systolic hypertension, isolated diastolic hypertension, and systolic/diastolic hypertension. Vascular dysfunction is involved in a vicious cycle with abnormal blood pressure variability. Furthermore, a vicious cycle may also exist between vascular dysfunction and hypertension. While the significances of vascular function tests to predict future cardiovascular events has been established in cases of hypertension, their usefulness in assessing the effectiveness of management of the vascular functions in hypertension on the cardiovascular outcomes has not yet been fully clarified. Thus, vascular dysfunction plays crucial roles in the pathophysiology of hypertension, and further research is warranted to establish strategies to improve vascular dysfunction in cases of hypertension. Vascular functions in the pathophysiology of hypertension. Vascular dysfunction and elevation of blood pressure are components of a vicious cycle even from their early stages, which including abnormal blood pressure variabilities. This vicious cycle is associated with hypertensive organ damage and also adverse cardiovascular outcomes. Strategies to break this vicious cycle have not yet been fully established.