When blood flows through an implant - a heart valve or a cardiac support system - it is briefly stressed by shearing and can then come into repeated contact with a foreign material in a flow separation. This combination of high and low shear favours the formation of thrombi. This is to be reproduced in a model.
You are here:
The aim is a closer understanding of Virchow's triad, in particular the formation of thrombi. A special plate-plate shear device is being developed for this purpose. Microscope cover glasses with a diameter of 35 mm and a gap of 50 µm form the space into which the blood is introduced and sheared. The picture shows a cross section.
The upper plate is rotatable and is driven by a slow-running motor via a toothed belt. A second drive provides a short and intensive shear pulse (100 ms, 20 Pa). The whole apparatus is placed on an inverse microscope. This allows the formation of a thrombus to be observed. This is recorded with a video camera. The first tests were carried out with whole blood and with a shear rate of 30 1/s. The formation of thrombi could already be observed after 20 s.