Relationship between the pulmonary artery index and physiological properties of the pulmonary vascular bed

Abstract

Background: To clarify the physiological significance of the pulmonary artery index (PAI), we examined the relationship between PAI and physiological properties of the pulmonary vascular bed. We also examined the limitations of PAI in practical use. Methods and Results: We examined the relationships between PAI and pulmonary vascular resistance (Rp), pulmonary arterial compliance (Cp), and the time constant (RC) of pulmonary circulation in 50 patients with congenital heart disease with decreased pulmonary blood flow. PAI was significantly related to Cp and RC (r=0.67, r=0.63, respectively). These correlations became more significant when we excluded patients in whom the central pulmonary arteries were disproportionately dilatated in contrast to the peripheral pulmonary arteries (r=0.80, r=070, respectively). Conclusions: PAI reflects the state of the pulmonary vascular bed, especially when the peripheral arteries develop in proportion to the central pulmonary artery.