Infirmary, Oxford SYNOPSIS Fibrous bands have been described in the elastic (conducting) pulmonary arteries in 38 cases at necropsy, which represents a necropsy incidence of 14-4 %. The fibrous bands are considered to represent one of the end results of episodes of pulmonary embolism. The formation of the bands is described and their significance is discussed in relation to their haemodynamic effects. Most of these bands are the result of clinically silent emboli.During the course of an investigation into the incidence and pathology of pulmonary embolism in hospital patients, the frequent occurrence of fibrous bands, often forming a lace-like network in the pulmonary arteries, was noted. The present paper describes such lesions found in the conducting arteries in 38 cases and discusses the origin and significance of the bands. In a smaller number of cases the lesions were noted in the muscular pulmonary arteries but these cases have not been considered in the following account.
METHODSThe right lung was taken from 263 cadavers representing a 1 in 5 selection at necropsy on patients who died in the United Oxford Hospitals, where the necropsy rate is 98 %. The lungs were all expanded by intrabronchial perfusion with 4% formaldehyde in saline. They were placed in a bath of fixative for two to six days and cut into 1 cm. thick slices, each of which was examined for arterial lesions. Blocks of all arteries containing pathological lesions were taken for histological examination, being fixed for a further 24 hours in a mercuric chloride formaldehyde saline mixture, dehydrated in alcohol, cleared in chloroform and embedded in paraffin wax.Sections 51& thick were cut and stained with haematoxylin and eosin, and by the periodic-acid-Schiff and trichrome methods.
RESULTSThirty-eight cases were found in which there were fibrous bands in the elastic pulmonary arteries. This represented a post-mortem incidence of 14-4%. In 27 of these cases there were more recent thrombi in addition to the fibrous bands. The age incidence of
Stimulation of the muscles of the lower limbs during surgery was evaluated as a means of preventing postoperative leg-vein thrombosis and pulmonary embolism. Of 285 patients submitted to a major operation, 113 were stimulated and 172 were not. The two groups were closely similar in age, operations, anaesthesia, diseases, and severity of disease, but there was a negligible difference in the rates of postoperative thrombosis.
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