Hypertrophic obstructive cardiomyopathy with associated pulmonary arteriopathy: A histopathologic perspective from sudden cardiac death

Hypertrophic obstructive cardiomyopathy (HOCM) is one of the common causes of sudden cardiac death which can be associated with pulmonary vascular remodelling changes also known as Pulmonary Arteriopathy (PA). Pulmonary Arteriopathy (PA) is a condition affecting the pulmonary arteries, characterised by a range of proliferative and obstructive vascular lesions that ultimately result in lumen obstruction. It may manifest under diverse settings, encompassing both acquired and congenital disorders. We present a case of a 52-year male with no previous known history of illness or disease, who was brought to the Emergency department and was pronounced dead upon arrival. During the autopsy, the heart exhibited left ventricular thickness (3 cm thick) and the interventricular septum thickness (2.5 cm thick). Histopathological examination revealed localised myocardial disarray, muscle fibre hypertrophy, and nuclear enlargement, indicative of left heart disease characterised by left ventricular hypertrophy. The histopathological examination of the both lungs revealed that the blood vessels exhibited thickened walls, characterised by medial wall hypertrophy, manifesting as muscularization suggestive of Grade 2 Pulmonary Arteriopathy (PA). This case examines the pathophysiological mechanisms connecting the characteristics of cardiomyopathy, pulmonary arterial hypertension, and pulmonary arteriopathy, thereby emphasising the significance of pulmonary vascular alterations as a consequence of HOCM but also as a sign of disease progression. Other causes of pulmonary arteriopathy along with advanced ageing should be ruled out in such cases.