Aerosolized iloprost for pulmonary vasoreactivity testing in children with long-standing pulmonary hypertension related to congenital heart disease

Abstract

Background: In congenital heart disease with increased pulmonary blood flow and pressure, progressive changes in the vascular structure can lead to irreversible pulmonary hypertension (PH). Pulmonary hemodynamic parameters are used to determine whether surgical correction is no longer indicated. In this study, aerosolized iloprost was used to assess pulmonary vasoreactivity in children with long-standing PH related to congenital heart disease.

Methods: Children with long-standing and severe PH secondary to congenital heart disease were included in this study. Various hemodynamic parameters were measured before and after iloprost inhalation (0.5 microg/kg), and vascular resistance was determined. Responders to the iloprost test were defined as those with a decrease in both pulmonary vascular resistance (PVR) and pulmonary-to-systemic vascular resistance ratio (R(p)/R(s)) of >10%.

Results: Eighteen children aged between 7 months and 13 years with long-standing and severe PH secondary to congenital heart disease were studied. Thirteen children had a positive response, resulting in a mean (+/- SD) decrease of PVR from 9.3 +/- 4.6 to 4.6 +/- 2.7 Wood U x m(2) (P < 0.001), and a mean decrease of R(p)/R(s) from 0.54 +/- 0.37 to 0.24 +/- 0.14 (P = 0.005).

Conclusions: Iloprost-induced pulmonary vasodilator responses vary among children with PH related to congenital heart disease. The use of inhaled iloprost in the cardiac catheterization laboratory results in pulmonary vasoreactivity for some of these children particularly a reduction in PVR and the pulmonary-to-systemic vascular resistance ratio.