Key Points : • Interventional therapies directed at fenestration closure in the Fontan patient must rely on good hemodynamic data • The Large Optimus-CVSTM stent is an additional armamentarium for fenestration closure however, longer term follow up is needed • Multi institutional studies defining the long-term benefits of fenestration closure and outlining fenestration management guidelines may help improve the long-term morbidity and mortality in this group of patients.