Great Ormond Street UK and Ireland populationbased Congenital Heart Surgeons Toronto UCLA, Los Angeles 1976– 1989a 1991– 1995 1987– 1997 1992– 1998a 1982– 2001 135 72%b 49%b Bull et al.115 183 71%c 64%c Daubeney et al.9 408 68% 60% Ashburn et al.116 210 75% 67% 106 88%b 86% Dyamenahalli et al.118 Odim et al.121 a Uses most recent era data from the study bEstimate of mortality at 1 and 5 years cSurvival of those who underwent a procedure FIG 43.17 Kaplan-Meier survival curves for subgroups of patients with pulmonary atresia and intact ventricular septum RV, Right ventricle; RVOT, Right ventricular outflow tract (Data from Daubeney PEF, Wang D, Delany DJ, et al Pulmonary atresia with intact ventricular septum: predictors of early and medium-term outcome in a population-based study J Thorac Cardiovasc Surg 2005;130:1071.) Why this lesion should have such a poor outcome is not well identified, and optimal strategies for treatment remain to be elucidated The largest four studies have identified risk factors for poor outcome These include factors relating to the small size of the RV, dilated right ventricular size, low birth weight and prematurity, presence of right ventricular-to-coronary artery fistulous connections, and an RV-dependent coronary arterial circulation.55,114–118 As more is learned about adverse risk factors, clinicians are tailoring their approach; for example, by not decompressing RVs where there is thought to be an RVdependent arterial circulation Freedom and colleagues stated in 2005 that “ventriculo-coronary connections, and a right ventricular dependent coronary circulation, an important risk factor in our earlier surgical experience,117,119 therefore, had been effectively neutralized by the introduction of the functionally univentricular palliation.”2 Catheter perforation of the imperforate pulmonary valve is now a wellestablished technique for primary intervention It accounted for 60% of all valvotomies performed without concomitant construction of a shunt in the study carried out in the United Kingdom and Ireland.55 When analyzed on the basis of intention to treat, survival was similar between those treated at catheterization or surgically A recent report notes ongoing technical improvement, with a mortality of only 10%.107 Successful perforation of the atretic pulmonary valve is not guaranteed, but published rates of success range from 85% to 90%.104–106 Longer-term outcomes (median, 9.2 years [range, 2.2 to 21 years]) of this procedure have also been reported, indicating an early mortality of 21%, but no late deaths after the first 35 days.111