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patients with surgical interventions for pulmonary valve stenosis have a risk for ventricular arrhythmias, and therefore require a dedicated workup of any clinical symptoms such as palpitations or syncope, as suggested by Ruckdeschel and colleagues.137 Balloon Dilation Acute results of balloon pulmonary valvuloplasty are excellent, usually leading to a significant reduction in the transvalvar gradient There is, however, a wide variety of what is considered a successful procedural outcome when related to the residual gradient, with reported success criteria ranging anywhere from less than 20 to less than 35 mm Hg.119,138 Other criteria that have been used to define procedural success include a gradient reduction by more than 50%, or a reduction of the right ventricle to systemic pressure ratio by more than 50%.120 Early results from the VACA registry (784 pulmonary valvuloplasties) documented a significant decrease in gradient from 71 to 28 mm Hg.117 More recent results from the Improving Pediatric and Adult Congenital Treatment registry documented that a gradient reduction to less than 20 mm Hg was achieved in 73% of 268 patients undergoing balloon pulmonary valvuloplasty.119 Holzer and colleagues reported on the results of the C3PO registry, where 88% of patients achieved a gradient reduction to 25 mm Hg or less, 79% a gradient reduction by 50% or more, and 45% a reduction in the right ventricle to systemic pressure ratio by 50% or greater.120 Procedural success using either of those three criteria was achieved in 91% of cases In multivariate analysis, the only independent risk factors for procedural failure were moderate or severe pulmonary valve thickening, and the presence of supravalvar pulmonary stenosis Patients with critical pulmonary valve stenosis presenting in the neonatal period are often more difficult to manage, and depending on the size and morphology of the right ventricle and tricuspid valve, the outcomes and need for additional procedures may more closely resemble that of patients with pulmonary atresia and intact ventricular septum (discussed in Chapter 43) Shaath and colleagues recently evaluated the acute and short-term outcome comparing 23 patients with critical pulmonary valve stenosis to 20 patients with pulmonary atresia and intact ventricular septum.99 Reinterventions were significantly more frequent in patients with pulmonary atresia and intact ventricular septum (55%) when compared to patients with critical pulmonary valve stenosis (17%) A study by Yucel and colleagues reported that 38% of neonates that underwent balloon valvuloplasty for critical pulmonary valve stenosis required pulmonary blood flow augmentation after pulmonary valvuloplasty.139 Karagoz and colleagues reported a 30% incidence of reintervention within 8 months of the procedure in 50 patients with a weight less than 3 kg undergoing balloon pulmonary valvuloplasty.140 Although most pediatric patients with pulmonary valve stenosis are asymptomatic, adult patients often experience symptoms such as fatigue and dyspnea prior to balloon pulmonary valvuloplasty, which often improves after the procedure Taggart and colleagues evaluated 40 adults (78% symptomatic) and found an improvement in symptoms in 20 of 24 previously symptomatic patients following balloon pulmonary valvuloplasty (mean follow-up, 1.9 years).141 Long-term results of balloon dilation during childhood are excellent.131 Follow-up data reported from the VACA registry (up to 8.7 years) documented a suboptimal outcome in 15% of patients with typical valvar morphology and 65% of patients with a dysplastic pulmonary valve (overall 23%).138 Suboptimal outcome in this context was defined as either a residual right ventricle to pulmonary artery peak systolic gradient above 35 mm Hg, or the need for repeat valvuloplasty or surgical intervention Fig 42.36 shows the freedom from reintervention in a series of 150 children who underwent balloon pulmonary valvuloplasty for pulmonary stenosis between 1984 and 1992 Although late pulmonary incompetence commonly occurs, it appears well tolerated in the first decade after intervention For those children with severe pulmonary incompetence, longer follow-up is necessary to determine if they develop or can be predicted to develop progressive right ventricular dilatation and require replacement of the valve Lifelong follow-up is essential in children who have had balloon dilation where pulmonary incompetence is present FIG 42.36 Freedom from reintervention after balloon dilation of the stenosed pulmonary valve; 95% confidence intervals are indicated by the dotted lines Numbers above the x-axis indicate children at risk (From Garty Y, Veldtman G, Lee K, et al Late outcomes after pulmonary valve balloon dilatation in neonates, infants and children J Invasive Cardiol 2005;17:318–322.) In adults, balloon dilation is similarly feasible.72,107,142 Long-term follow-up has again been excellent, with minimal recurrence of pulmonary stenosis.74,143 Observed infundibular hypertrophy (Fig 42.37) and tricuspid incompetence resolves over time.73,144 In a large study of 127 adults who underwent balloon dilation, immediate relief of pulmonary stenosis was achieved, with further reduction in the measured gradient from 6 to 8 years later (Fig 42.38).74 ... reintervention within 8 months of the procedure in 50 patients with a weight less than 3 kg undergoing balloon pulmonary valvuloplasty.140 Although most pediatric patients with pulmonary valve stenosis are asymptomatic, adult patients often experience symptoms such as fatigue and