"Primary" pulmonary hypertension with coexisting portal hypertension. A retrospective study of six cases.

HE PATHOGENESIS of the syndrome "primary pulmonary arterial hyper-tension has been the subject of inereasing interest in recent years.12 The syndrome is characterized by pulmonary arterial hypertension in the absence of significant primary pulmonary parenchymatous disease or primary cardiac disorder. The hypertension has usually been attributed to pulmonary vascular lesions, which increase the resistance to blood flow through the lesser circulation. In most cases the most striking vascular change has been proliferation of endothelial cells and fibrous tissue in the intima of small pulmonary arteries. In a few individuals pulmonary arterial thrombi have been numerous, suggesting that the sclerotic process may have been the consequence of recurrent emboli.1-5 In many other cases the most prominent vascular alteration has been an acute or healing arteritiS.l, 6, 10-12 In some of these instances it has been difficult to determine whether the arteritis preceded the hypertension or was its consequence.6" 13 In any case, the final sclerotic lesions give few indications of their origin, the healed lesions of arteritis often being indistinguishable from those that follow enibolism or other forms of trauma to the pulmonary arteries.14' 16 The syndrome of " primary" pulmonary hypertension may well have a diverse etiology. "Primary" pulmonary hypertension has rarely been related to other disorders. Only 3 examples of an association between "primary" pulmonary arterial hypertension and portal venous hypertension have been reported.'7-19 In one, recurrent pulmonary emboli arose from a spontaneously developing