26 MICROCALCIFICATION OF THE INTERNAL ELASTIC LAMINA AND PULSATIL BLOOD FLOW

Abstract

It has been shown that a change in velocity and modulation of the pulse wave alters the functional behaviour of organs perfused in this way even if the volume of flow is normal. The extreme example is continuous flow in an experimental model. Such changes are very difficult to measure in humans. However, it has also been shown that there are changes in the impedance of the arterial wall with alterations of the viscoelastic properties of its cellular structure. In the course of a study on the arteries of children hypertensive because of various reasons special stains showed microcalcifications restricted to the internal elastic lamina in muscular arteries. These calcifications were very often segmental in nature, but on ocasion involved the entire circumference of the vessel lumen indicating the presence on non-pulsatil flow. The post-mortem fracture of the calcified segment produced by the spastic contraction of the artery demonstrates the rigid nature of the calcified segment in-vivo. The very presence of a segmento of calcified and non-elastic limiting membrane implies that the systolic and diastolic movements of the media were not normal and circumferential, and produce or are the consequence of alterations of the pulse wave. Therefore it is necessary to search for this morphologic indicator of pathologic circulatory dynamics in all cases of hypertension in children, specially in those considered to be “essential” in nature.