Outcome Predictors in Catheter Interventions for Severe Right Ventricular Outflow Tract Obstructions.

Introduction & Aim Of Work: Transcatheter treatment for critical pulmonary stenosis and membranous pulmonary atresia has become the gold standard of care in many centers. We aimed at evaluating the predictors of outcome in interventions for treatment of duct-dependent right ventricular outflow tract obstruction with intact interventricular septum.

Subjects & Methods: 68 cases with pulmonary atresia with intact interventricular septum (PA/IVS) and 50 cases with critical pulmonary stenosis (CPS), all younger than 3 months of age, were operated during the period of 10 years; excluding patients with tricuspid valve annulus Z-score smaller than -4, evidence of right ventricular-dependent coronary circulation or additional malformations.

Results: Age, weight, body surface area as well as tricuspid & pulmonary valve Z-scores were significantly less in PA/IVS; right ventricular pressure was similar in both groups however procedural success and survival to hospital discharge was higher in the CPS group. Lower age, weight and body surface area were associated with procedural failure. Weight was the only predictor of procedural success; while weight and lower post-procedural right ventricular pressure were independent predictors for survival to hospital discharge. Post-procedural right ventricular pressure and length of stay were less in the CPS group. tricuspid and pulmonary valve annulus Z-scores were the only independent predictors of the post-procedural milrinone duration in PA/IVS.

Conclusion: We advocate for the use of larger balloon/pulmonary annulus ratio, to achieve a lower right ventricular pressure not fearing excessive pulmonary regurgitation that might be beneficial for right ventricular growth; and for the combination with ductal stenting in borderline or bipartite right ventricles.