[Direct vasodilatation effect of flosequinan on pulmonary vascular bed. Estimation by digital perfusion images]

Flosequinan (F) is a potent vasodilator and produces hemodynamic improvement when given to patients (pts) with congestive heart failure (CHF) but little is known about its direct effect on the regional pulmonary vascular bed. Pulmonary perfusion in erect position is known to vary according to the changes of pulmonary hemodynamics. To determine the acute effect of F on pulmonary perfusion 17 pts with CHF (NYHA 2-3, ejection fraction 30 +/- 10%) underwent Tc-99m-MAA pulmonary perfusion images in erect position before and 2 hours after administration of 100 mg dose of F. Pulmonary perfusion were assessed by ratio of upper to lower zone counts in the images (U/L). Increase rate of the lower zone area was assessed by delta L/L (delta L, %). delta L was thought to correspond to increase rate of pulmonary perfusion in the lower lung zone. In all pts significant decrease in U/L (0.82 +/- 0.22----0.63 +/- 0.24 p less than 0.001) was noted. delta L was 9.6 +/- 6.4%. Increase in perfusion to the lower lung zone indicated localized vasodilatation effect of F. In 11 pts with basal hyperperfusion area U/L improved from 0.63 +/- 0.08 to 0.49 +/- 0.07 and mean delta L was 9.6 +/- 6.4%. This showed increase of pulmonary perfusion in the lower zone. In 3 pts of 6 pts without basal hyperperfusion area pulmonary perfusion in the lower zone markedly increased and hyperperfusion area noted in the upper zone disappeared after administration of F. delta L was 21, 32 and 29% respectively. This corresponded to the dilation of pulmonary vascular bed in the basal zone.(ABSTRACT TRUNCATED AT 250 WORDS)