Objective: To compare the acute hemodynamic effects of adenosine versus iloprost in patients of pulmonary arterial hypertension (PAH) complicated with connective tissue diseases.
Methods: During right heart catheterization, 18 patients of PAH complicated with connective tissue diseases sequentially received intravenous infusion of adenosine and inhaled iloprost. After the baseline hemodynamic data were obtained, an adenosine infusion was started and titrated to the maximal tolerated dose. The hemodynamic parameters were allowed to return to baseline. Then inhalation of iloprost was administered. The effects of both medicines on the patient's hemodynamics were monitored.
Results: As compared with the baseline values, the systolic pulmonary artery pressure and pulmonary vascular resistance significantly decreased [(71 +/- 30) vs (80 +/- 29) mm Hg and (712 +/- 440) vs (824 +/- 464) dyn x s x cm(-5) respectively, both P < 0.05) while the heart rate increased significantly [(93 +/- 17) vs (83 +/-16) beat/min, P < 0.05] in the adenosine group. Inhaled iloprost could also lower the systolic pulmonary artery pressure [(66 +/- 29) vs (79 +/- 28) mm Hg, P < 0.05], mean pulmonary artery pressure [(43 +/- 19) vs (52 +/- 19) mm Hg, P < 0.05] and pulmonary vascular resistance [(632 +/- 440) vs (816 +/- 448) dyn x s x cm(-5), P < 0.05] without any effect upon heart rate. Inhaled iloprost exerted more potent effect on lowering mean pulmonary artery pressure and pulmonary vascular resistance than adenosine (P < 0.05). The two medicines did not affect cardiac output, pulse oxygen saturation or systemic blood pressure. The side effects were fewer in the iloprost inhalation group than the adenosine group.
Conclusion: During acute vasodilator testing, inhaled iloprost was more potent than infused adenosine as a pulmonary vasodilator in PAH complicated with connective tissue diseases.