CLINICAL STATEMENTS AND GUIDELINES when there is marked dysplasia of the pulmonary valve or significant hypoplasia of the annulus. 3. Relief of a severely stenotic pulmonary valve in an asymptomatic patient will reduce the RV pres- sure and the possibility of potential sequelae. As in symptomatic patients, the procedure can be per- formed by surgery or interventional catheterization with low morbidity and mortality. If intervention is deferred, careful follow-up to evaluate for symp- toms, decline in exercise capacity, worsening RV function, or development of cyanosis is important and may prompt reconsideration of intervention. 4.3.1.1. Isolated PR After Repair of PS Recommendations for Isolated PR After Repair of Pulmonary Stenosis COR LOE Recommendations I C-EO In symptomatic patients with moderate or greater PR resulting from treated isolated pulmonary stenosis, with RV dilation or RV dysfunction, pulmonary valve replacement is recommended. I C-EO For asymptomatic patients with residual PR resulting from treatment of isolated pulmonary stenosis with a dilated right ventricle, serial follow-up is recommended. IIb C-EO In asymptomatic patients with moderate or greater PR resulting from treatment of isolated pulmonary stenosis with progressive RV dilation and/or RV dysfunction, pulmonary valve replacement may be reasonable. Synopsis Although many patients with valvular PS do not require intervention, some have PS that is severe enough to warrant intervention, often in infancy or childhood. PS can be alleviated either by surgical valvotomy or with balloon valvuloplasty. Either surgical or catheter inter- vention may result in hemodynamically important PR that can result in symptoms, RV enlargement, and/or dysfunction requiring pulmonary valve replacement. Recommendation-Specific Supportive Text 1. Patients with isolated PS who have previously undergone an intervention on the pulmonary valve require ongoing clinical follow-up and mon- itoring of PR, RV size and function, and functional capacity. This may include echocardiography, CPET, and advanced imaging. 