Atheroma and arterial wall shear - Appendix I, II, III

For purposes of studying flow patterns and wall-shear rates a hollow transparent cast was made of a human aorta. A solid cast was made first (figure 7, plate 3), by a technique similar to that described by Tompsett (1958, 1967). The subject was a 31-year-old woman (normal physique and previous medical history) who had died following an overdose of barbiturate. With the cadaver supine, thoracotomy was performed and the lungs were allowed to collapse. The left ventricle was opened and a cannula was inserted and secured in the root of the aorta. A cannula was also inserted and secured into the superior vena cava and the arterial system was flushed with saline (Tompsett 1967). The innominate, left common carotid and subclavian arteries, the major branches of the abdominal aorta and the internal and external iliac arteries were then ligated about 4 cm from their origins. Needle punctures were made proximal to the ligatures, as well as at a high point on the aortic arch, to allow escape of saline or entrapped air. The resin was introduced at a pressure sufficient to cause normal distension of the aorta, as judged by appearance and palpation. The preparation was allowed to harden for 3 h. After this time, the aorta, together with short segments of the arteries mentioned, was removed. Separation of the cast from the vertebral column caused fracture of most of the intercostal arteries, close to their origins. The cast was allowed to harden for a further 24 h; soft tissue was then digested away with hydrochloric acid.