The Significance of Adventitial Infiltrations in Coronary Atherosclerosis

There are a large number of deaths from coronary disease in which a necropsy examination generally gives less evidence of the exact cause of death than the clinical findings.In the absence of fatal structural lesions, acute coronary deaths have been attributed to disturbances of function such as inhibition, arrhythmias, and coronary spasm; but the problem has been one of debate rather than observation.Albutt rejected the spasm theory in no uncertain terms, saying " The truth is, spasm of the coronary arteries is a nosologist's conceit to explain puzzles of his own making."The object of this investigation was to attempt to establish some correlation between the histological features of the coronary arteries and the mode of dying.Attention was directed to the changes in the adventitia and in particular to the frequent occurrence therein of discrete foci of inflammatory cells.The incidence of these lesions is analysed, the appearances described, and their significance discussed. METHODThe observations presented here are based on the histological examination of the coronary arteries obtained from 160 necropsies.Of these, 101 were from cases dying of coronary artery disease, and 59 from cases in which death was due to some other cause.These are hereafter referred to as " coronary cases" and " non-coronary cases."The coronary cases were classified independently of the histological findings into three groups.Group I: sudden deaths with coronary atherosclerosis, but no macroscopic evidence of thrombosis or myocardial infarction or fibrosis.Group II: sudden deaths with old infarction or myocardial fibrosis.Group III: deaths due to recent myocardial infarctions.To some extent this may be considered as a classification of the immediate cause of death.In Group I the immediate cause of death was a functional disturbance rather than an anatomical lesion.In Group II, anatomical lesions were present and may be implicated, although, as these were old lesions, their presence may not always have had direct bearing on the mode of death.In Group III the anatomical lesions were more recent and may reasonably be considered to have had a more direct relationship to the immediate cause of death, although a terminal functional disturbance could not be excluded.In all cases the histological appearances were graded according both to the degree of atheroma and to the degree of focal adventitial infiltration.The degree of atheroma was arbitrarily assessed according to the degree of the narrowing of the lumen, and divided into four grades.Grade 0: no atheroma.Grade I: slight atheroma with insignificant narrowing of the lumen.Grade II: moderate narrowing of the lumen.Grade III: complete or almost complete occlusion.The adventitial changes were classified into four grades.Grade 0: no adventitial infiltration (negative).Grade I: a scanty incidence of small or early focal infiltrations.Grade II: a small or moderate number of well-formed foci.Grade III: many well-formed foci.Grades I, II, and III are collectively referred to as "positive."