Fibrous bands in conducting pulmonary arteries

Abstract

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

Autopsy‐proven untreated previous pulmonary thromboembolism: frequency and distribution in the pulmonary artery and correlation with patients’ clinical characteristics

“…2). Perhaps these patients were clinically considered as non‐specific, because some autopsy investigations have revealed a not insignificant incidence of organized thrombi in patients that died of other diseases [11–13]. However, we consider that the existence of organized thrombi, especially in acute PE cases, suggests the previous occurrence of PE.…”

“…There was a significant preference for the subsegmental branch inherent in the distribution pattern of organized thrombi. Thromboemboli are usually lodged and organized at the bifurcation of the elastic artery [9,11]. These previous studies indicated that the subsegmental branch is a preferred site for PE, both trapped and organized.…”

Elevated Expression of Urokinase-like Plasminogen Activator and Plasminogen Activator Inhibitor Type 1 During the Vascular Remodeling Associated With Pulmonary Thromboembolism

“…Resolution of pulmonary thromboemboli is usually derived by mechanical fragmentation, endogenous thrombolysis, or reparative organization through invasion with fibroblasts and capillary buds, which occurs in the majority of survivors, leaving behind intimal thickenings and bands, 4 with restoration of normal pulmonary hemodynamics. 5,6 In a small percentage of cases, pulmonary thromboemboli persist and undergo extensive organization, with subsequent obstruction of the pulmonary vascular bed and the development of pulmonary hypertension.…”

Perfusionsstörungen

“…Sie bestehen in einer teils knötchenförmigen, teils halbmondförmigen fasrig-fibrösen Verdikkung der Intima, in die je nach Alter der Narbe feinste elastische Lamellen eingebaut sind (KÖNN et al 1978). Nach vollständigem Verschluß durch den Embolus können fibröse Bänder, ausgespannt innerhalb der Gefäßlichtung, entstehen (MoRRELL et al 1967). Die makroskopisch mitunter zu beobachtenden strickleiterartigen Narben in den Lungenarterien kommen dadurch zustande, daß die den Embolus durchsetzenden Gefäße Anschluß an den offenen Teil der Pulmonalgefäßlichtung finden.…”