Ventilation-perfusion relationships in pulmonary arterial hypertension: effect of intravenous and inhaled prostacyclin treatment.
In seven patients with idiopathic or secondary pulmonary arterial hypertension (PAH), ventilation-perfusion (V (A)/Q ) relationships were measured during a right heart catheterization using the multiple inert-gas elimination technique before and during intravenous infusion with epoprostenol (EPO), and following 5 months of 20 microg inhaled iloprost taken three times daily (ILO). Pre-treatment pulmonary vascular resistance (PVR) was 9.3+/-5.0 mmHg/l/min and the dispersion of perfusion and ventilation for V (A)/Q -ratios was increased. EPO reduced PVR by 20%, and increased cardiac output, shunt, and mixed venous oxygenation (SV(O2)). The arterial oxygen tension (Pa(O2)) remained unchanged. Basal central haemodynamics did not change after 5 months of ILO. Fifteen minutes after ILO, PVR decreased by 20%, and the shunt, SV(O2), and Pa(O2) remained unaltered.


CONCLUSIONS
In secondary PAH with normal lung volumes, significant V (A)/Q mismatching occurred. The PVR was reduced to a similar degree during EPO and after ILO, but only EPO increased the shunt and SV(O2). EPO and ILO did not significantly affect the Pa(O2).
Bratel
Tomas
T
Division of Respiratory Medicine, Department of Medicine, Karolinska University Hospital, Solna, S-171 76 Stockholm, Sweden. tomas.bratel@karolinska.se
Lagerstrand
Lars
L
Brodin
Lars-Ake
LA
Nowak
Jacek
J
Randmaa
Ivar
I
D000284:Administration, Oral; D000368:Aged; D001794:Blood Pressure; D006328:Cardiac Catheterization; D004452:Echocardiography; D011464:Epoprostenol / Q000008:administration & dosage / Q000627:therapeutic use*; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006976:Hypertension, Pulmonary / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology*; D001239:Inhalation / Q000187:drug effects / Q000502:physiology*; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011788:Quality of Life; D013599:Systole; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014797:Vital Capacity
D010975:Platelet Aggregation Inhibitors; D011464:Epoprostenol