FIG 42.34 A 15-year-old male with moderate pulmonary valve stenosis Top, Right ventricular angiogram documenting a thickened and doming pulmonary valve Bottom, Double balloon pulmonary valvuloplasty using two high-pressure balloons A-plane projections to the left and lateral projections to the right The use of the multitrack double balloon mitral commissurotomy system, employing two complementary angioplasty catheters designed to track along the same guidewire, has been reported in adults with pulmonary stenosis.111 Although this technique offers an easier approach and one less venous puncture than the conventional double-balloon technique, again it offers an advantage only if a single balloon of appropriate dimension is not available Similarly, angioplasty catheters with multiple balloons, bifoil and trefoil, mounted in parallel on one shaft, have been described,112 as well as a technique using three separate angioplasty balloons with a complicated formula described for their overall dimensions.113 Such balloons or systems as well as the double-balloon technique are argued by their proponents to facilitate some residual antegrade flow during inflation in the right ventricular outflow tract This seems unlikely when the correct oversized dimension is chosen In addition, they are bulky and have been largely superseded by more modern large single balloons with lower profiles needing smaller sheaths Although all these techniques have had highly effective and well-sustained results, it has since been shown that where a single balloon is available for the appropriate dimension, no advantage is conferred by using multiple balloons.114 It is important, nonetheless, that all operators have an understanding of these techniques as well as knowledge of the equipment that is available in their own local laboratories because the final decision may be made on the basis of supply and demand of equipment Adverse Events Compared with many other procedures performed in the congenital catheterization laboratory, balloon pulmonary valvuloplasty is usually a fairly safe procedure with low risks Based on data from the C3PO registry, the procedure has been classified as risk category 2 (out of 4) for patients 1 month of age or older, and as risk category 3 for neonates younger than 1 month of age.115 Acute complications of balloon dilation of the pulmonary valve are rare, and most of these are nonspecific to pulmonary valvuloplasty and represent general catheterization related adverse events These include adverse events related to anesthesia, arrhythmias and conduction anomalies, vascular and cardiac trauma, as well as vascular entry site related complications such as femoral venous occlusion related to the intervention that may be demonstrated in more than 20% of patients requiring further venous access.116 Tricuspid valve injury and severe reactive subpulmonary stenosis are some of the rare but more specific and significant procedure-related adverse events that have been described Rupture of the pulmonary artery/right ventricular outflow tract is exceedingly rare and can be almost completely avoided when using the recommended balloon to annulus ratio of 120% to 125% Balloon dilation has proved to be very successful, and it has yielded minimal immediate complications Out of 822 procedures entered into the VACA Registry, including cases of critical pulmonary stenosis, the mortality was reported as 0.24%, and the major complication rate only 0.35%.117 In a smaller multicenter series of 172 patients, excluding critical pulmonary stenosis, there was no mortality with emergency surgery required in only one patient (0.58%) who suffered perforation of the right ventricular outflow tract.118 Results from the Improving Pediatric and Adult Congenital Treatment registry of 268 patients undergoing balloon pulmonary valvuloplasty documented acute adverse events during the same episode of care in 7.1% of cases, with no major adverse events and no unplanned surgeries.119 Results from the C3PO registry (211 cases of balloon pulmonary valvuloplasty) documented an incidence of 9% for low-severity adverse events (levels 1 to 2) and 3% for higher severity adverse events (levels 3 to 5).120 Only one major adverse event was reported in this study, which was an episode of ventricular fibrillation during balloon pulmonary valvuloplasty requiring electrical defibrillation By multivariate analysis, independent risk factors for any adverse event were patient age below 1 month and operator experience of less than 10 years During inflation of the balloon, transient bradycardia and hypotension may be observed This effect recovers quickly after deflation of the balloon A patent oval foramen or an atrial septal defect helps to preserve systemic ventricular output during occlusion of the pulmonary arteries To minimize these effects, inflation of the balloon should not be maintained for more than a second or two With the modern design of sheaths and catheters and improved techniques, loss of blood is minimal Manipulation of the catheter or wire in the right heart can provoke arrhythmia, right bundle-branch block, and even transient or permanent complete heart block Other complications include stroke or seizures due to embolic complications in the context of a potential right-to-left atrial shunt Rupture of the balloon at high pressures of inflation, pulmonary arterial tears,121 perforation of the right ventricular outflow tract,118 and rupture of tricuspid valvar papillary muscles have all been reported.87,122 Failure of ... who suffered perforation of the right ventricular outflow tract.118 Results from the Improving Pediatric and Adult Congenital Treatment registry of 268 patients undergoing balloon pulmonary valvuloplasty documented acute adverse events