PULMONARY OSSIFIC NODULES IN MITRAL VALVE DISEASE

Open Access
Publisher Website
Google Scholar
Abstract
In a routine radiological survey of 204 patients with mitral valve disease, 27 patients (13%) were found to have clearly defined pulmonary ossific nodules. They were present three times as often in men as in women, when allowance was made for the sex ratio in the series as a whole. They appear to be much more common than previously supposed, probably because attention has been focused on the more florid radiological appearances. In addition, the lungs from eight patients with mitral stenosis examined carefully at autopsy were all found to contain ossific nodules despite their absence radio-logically, again favouring the view that nodules are common. These cases were reviewed with reference to clinical findings, other radiological features, catheter studies, and the presence of valve calcification assessed at operation. There was no apparent relationship to age, symptomatology, cardiac rhythm, heart size, pulmonary arterial hypertension, hemosiderosis, or valve calcification. The most significant finding was pulmonary venous hypertension, which was present in 24 of the 27 patients with nodules, using one or more of three criteria of its presence: that is, a history of paroxysmal dyspnea, septal lines on the chest film, and a pulmonary wedge mean pressure of 20 mm Hg or more. Pulmonary venous hypertension was inferred in 2 of the 3 others who had an operation because of progressive symptoms. The nodules were shown histologically to be intra-alveolar and composed of lamellar bone formed on a basis of osteoid tissue, there being no evidence of calcification preceding the bone formation. It is suggested that the ossific nodules develop in areas of subacute pulmonary intraalveolar edema, indirectly due to a raised pulmonary venous pressure. The nodules are more numerous in the lower lobes, and this may depend on a hydrostatic effect producing a relatively higher pressure than in the upper lobes. A patient with a left atrial myxoma with ossific nodules is described; and this is presented as additional evidence favoring the hypothesis that pulmonary venous hypertension is the critical factor in the pathogenesis of the nodules. In mitral valve disease and particularly in mitral stenosis there is a sufficiently prolonged period of pulmonary venous hypertension for the necessary pathological changes to develop.