Acute pulmonary oedema in patients with primary pulmonary hypertension and normal pulmonary capillary wedge pressure.

Acute pulmonary oedema with normal pulmonary capillary wedge pressure, occurred in 2 patients with primary pulmonary hypertension, probably due to venoocclusive diseases. In both cases an increase in cardiac output induced by vasodilator therapy with a calcium antagonist or a viral infection with fever lead to an increase in hydrostatic pulmonary capillary pressure which was not identical to the pulmonary capillary wedge pressure.