Medial hyperplasia obliterans of the intramural coronary arterial vessels.
Primitive structural changes of the tunica media of the intramural coronary small arterial branches have been observed in 52 per cent of 208 unexpected sudden coronary death cases and in 78 per cent of 97 normal subjects dying by accident. These changes consisted in hyperplasia and hypertrophy of the smooth muscle cells with longitudinal and oblique bundle formation, dramatic thickening of the media and fibrous replacement with lumen reduction. No aneurysms, inflammatory reaction or abnormal depositions have been observed. This process, defined as "Medial hyperplasia obliterans", showed a preferential location in the anterior papillary muscles, columnae carneae, superior interventricular septum. When present the number of "hyperplastic" vessels ranged from one to a maximum of forty-four per section. No relation was found with acute or chronic myocardial damage, heart weight, sex and age and sudden death. From the present data these medial structural changes and their aging appear to be a physiological response of the arterial wall to functional factors linked with the regional myocardial contraction. The correct recognition of this overlooked pattern seems important to avoid pathogenic misinterpretations and erroneous diagnosis of small vessel disease in case of endomyocardial biopsy.
D003331:Coronary Vessels / Q000473:pathology*; D003645:Death, Sudden / Q000473:pathology; D006801:Humans; D006965:Hyperplasia; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D009206:Myocardium / Q000473:pathology