We report the hemodynamic and clinical effects of acute and chronic administration of iloprost in two patients with severe pulmonary hypertension caused by toxic oil syndrome. We tested the acute effect of progressive increments of iloprost, followed by long-term infusion of the drug during 14 days. The acute response produced an increase in cardiac output and moderate reduction in pulmonary vascular resistance, with no change in pulmonary artery pressure. Nevertheless, a maintained reduction in pulmonary artery pressure and resistance, as well as clinical improvement, was observed after chronic infusion. We conclude that (1) the acute effect of iloprost does not necessarily predict long-term hemodynamic response, and (2) iloprost given in long-term infusion seems to have been an efficacious and safe drug in our two patients, and it opens a new line of treatment.

Objective. To determine the effects of short-term, maximum-tolerated-dose and long-term, optimum-dose iloprost treatment of severe pulmonary hypertension associated with systemic sclerosis (SSc) and the primary antiphospholipid syndrome (APS).Methods. Three patients with SSc and 2 with APS who had failed to respond to oral vasodilator therapy for pulmonary hypertension were enrolled in a 32-week, open, prospective trial. Short-term infusion of maximumtolerated doses and continuous infusion of optimum doses of iloprost were carried out following baseline cardiac catheterization. Catheterization was repeated at 2 and 32 weeks. All 5 patients completed the study and continued therapy for an average of 82 weeks (range 58-103).Results. Acute infusion of maximum tolerated doses significantly ameliorated the cardiac index (0.92 liters/minute/m2; P < O.OI), pulmonary artery 0, saturation (10.6%; P < 0.05), and pulmonary resistance (-6.7 units; P < 0.05). After 2 weeks of continuous infusion of optimum doses, there was improvement in pulmonary resistance (216%) and pulmonary artery 0, saturation (>30%) in the 2 patients with primary APS.

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