In this research project we propose to assess the predictive performance of the pulmonary vascular reactivity to acetylcholine test on the presence of elevated PAH 1 year after the closure of the shunt. This reactivity test will be evaluated on a population of patients for whom the decision of the surgical closure of the shunt has been adjudicated on the basis of explorations and usual tests (and therefore blind to the knowledge of the result of the reactivity test). The test in this study is designed with repeated injections and increasing doses with a continuous flow of acetylcholine in the left lower lobe of the pulmonary artery. The last injection consisted with adenosine with inhaled O2/NO (potentiating effect) for maximum vasodilatation. The parameter of interest is the Doppler flow velocity in the pulmonary artery endothelium-dependent vasodilation by acetylcholine relative to the speed at maximum vasodilatation (adenosine + in nitric oxide (NO) inhalation)