[Critical pulmonary valve stenosis in neonates; treatment with balloon valvuloplasty using an arteriovenous loop and gradual dilatations]. / Estenosis pulmonar valvular crítica del recién nacido; valvuloplastía con globo efectuada usando un asa arterio-venosa y dilataciones secuenciales.

Critical pulmonary stenosis of the newborn is an emergency and the balloon dilatation can represent its definitive treatment. This procedure has important technical aspects related with the age and weight of patients and to anatomical factors that contributes to the obstruction. We present the case of a 20 days old newborn with this problem, in whom the use of an arterio-venous loop through the ductus arteriosus allowed the passage of balloon catheters of gradually increasing diameter until a balloon/pulmonary annulus index of 1.4 was reached. This procedure can be performed safely in cases in whom the common technique is difficult to apply. The procedure allows a successful valvular dilatation.