Ventilation-perfusion Relationships in Pulmonary Arterial Hypertension: Effect of Intravenous and Inhaled Prostacyclin Treatment

Respir Physiol Neurobiol. 2007 Aug 15;158(1):59-69. doi: 10.1016/j.resp.2007.03.003. Epub 2007 Mar 12.

Abstract

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).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Aged
  • Blood Pressure
  • Cardiac Catheterization
  • Echocardiography
  • Epoprostenol / administration & dosage
  • Epoprostenol / therapeutic use*
  • Exercise Test
  • Female
  • Forced Expiratory Volume
  • Humans
  • Hypertension, Pulmonary / diagnostic imaging
  • Hypertension, Pulmonary / drug therapy
  • Hypertension, Pulmonary / physiopathology*
  • Inhalation / drug effects
  • Inhalation / physiology*
  • Injections, Intravenous
  • Male
  • Middle Aged
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Quality of Life
  • Systole
  • Vascular Resistance / drug effects
  • Vascular Resistance / physiology
  • Vital Capacity

Substances

  • Platelet Aggregation Inhibitors
  • Epoprostenol