Objectives Pulmonary arterial hypertension (PAH) is the commonest complication of left-to-right shunt congenital heart disease (CHD). Detection of pulmonary vascular reactivity is important for the evaluation of patient with PAH. This study aimed to investigate the acute hemodynamic responses to iloprost in patients with idiopathic PAH (IPAH) and PAH associated with systemic-to–pulmonary shunt CHD (PAH-CHD).
Methods This study included a cohort of patients with IPAH and PAH-CHD. The inclusion criteria were: 1) IPAH with pulmonary artery systolic pressure > 70 mmHg measured by catheter and 2) PAH-CHD with pulmonary artery systolic pressure > 70 mmHg and pulmonary-to-systemic flow ratio (Qp / Qs) < 1.5. After determination of baseline haemodynamic parameters by cardiac catheterization, 10 μg of aerosol iloprost was inhaled and right heart catheterization was repeated.
Results A total of 165 patients (118 females) aged 29 ± 13 years were recruited, including 24 with IPAH and 141 with PAH-CHD. There were 2 acute positive responders (8.3%) in patients with IPAH who benefited from the treatment of calcium antagonist thereafter. No positive responder was found in patients with PAH-CHD. Inhalation of aerosol iloprost induced significant decrease in pulmonary artery pressure (P > 0.01), pulmonary vascular resistance (P < 0.01) and pulmonary-to-systemic vascular resistance ratio (P < 0.05) in patients with both IPAH and PAH-CHD. However, significant increase in oxygen saturation of femoral blood was only observed in patient with PAH-CHD. A ≥ 10% decrease in both pulmonary vascular resistance and pulmonary-to-systemic vascular resistance ratio at the end of drug exposure was observed in 58.9% of patients with PAH-CHD had but only in 45.8% of patients with IPAH.
Conclusions There are 8.3% of acute positive responders in patients with IPAH but no positive response in patients with PAH-CHD. Although iloprost induces decrease in pulmonary artery pressure and pulmonary vascular resistance in patients with patients with IPAH and PAH-CHD, the acute hemodynamic changes were different.