Restrictive ventilatory defect in a patient with primary pulmonary hypertension

A patient with the classic features of primary pulmonary hypertension developed a severe restrictive ventilatory defect that worsened during the clinical course. Histologic examination of the lung showed vascular changes consistent with primary pulmonary hypertension and no evidence of pulmonary parenchymal fibrosis. We suggest that severe progressive pulmonary hypertension caused a restrictive ventilatory defect in this patient.