Prostacyclin effect on cardiovascular system in man evaluated by echocardiography

This was an echocardiographic study of the cardiovascular effects of prostacyclin (PGI2) infused intravenously to human volunteers at the rate of 20 ng . kg-1 . min-1 for 10 minutes. The following parameters were recorded in the steady state, at one-minute intervals throughout infusion and the ensuing recovery period: systolic, diastolic, and mean blood pressure (SBP, DBP, MBP); heart rate (HR); left ventricle end-diastolic (EDD) and end-systolic diameter (ESD); stroke volume index (SVI); cardiac index (CI); peripheral vascular resistance (PVR); left ventricle fractional shortening (FS) and ejection fraction (EF). We detected a progressive reduction of MBP without any HR modification. MBP reduction was associated with a reduction of PVR and a parallel rise of CI and SVI. There was also an increase of FS and EF reflecting a reduced ESD. We conclude that PGI2 infused in man at the rate stated above causes hypotension reflecting an arterial vasodilating effect; a lack of heart rate reflex response to afterload reduction (probably a nerve-mediated effect of PGI2); and no venous vasodilation, judging from the absence of any change in end-diastolic diameter.