RELATIONSHIP BETWEEN THE PULMONARY-ARTERY INDEX AND PHYSIOLOGICAL-PROPERTIES OF THE PULMONARY VASCULAR BED

Background: To clarify the physiological significance of the pulmonary artery index (PAI), we examined the relationship between PAI and phys iological properties of the pulmonary vascular bed. We also examined t he limitations of PAI in practical use. Methods and Results: We examin ed the relationships between PAI and pulmonary vascular resistance (Rp ), pulmonary arterial compliance (Cp), and the time constant (RC) of p ulmonary circulation in 50 patients with congenital heart disease with decreased pulmonary blood flow. PAI was significantly related to Cp a nd RC (r=0.67, r=0.63, respectively). These correlations became more s ignificant when we excluded patients in whom the central pulmonary art eries were disproportionately dilatated in contrast to the peripheral pulmonary arteries (r=0.80, r=0.70, respectively). Conclusions: PAI re flects the state of the pulmonary vascular bed, especially when the pe ripheral arteries develop in proportion to the central pulmonary arter y.