Andersons pediatric cardiology 1121

Historical Perspective The swing to an interventional approach in the treatment of pulmonary valvar stenosis resulted from a partnership between cardiologists and radiologists The first case of catheter intervention for pulmonary valvar stenosis was reported in 1953.55 A ureteric catheter modified with a wire was introduced through the pulmonary valve, the wire being tensioned to form a bow-shaped device used to incise the stenosed valve.55 Later, the same technique was used for the stenosed tricuspid valve.56 The use of a standard angiographic balloon to disrupt the pulmonary valve was described in 1979.57 The technique involved a rapid pullback, in septostomy fashion, of the balloon catheter from the pulmonary trunk to the right ventricular outflow tract Meanwhile, graded dilation was being developed for atherosclerotic vessels,58 including important technical developments in guidewires and catheters.59,60 Further refinements allowed the techniques to be applied to smaller vessels, including the coronary arteries,61–64 using a double-lumen balloon catheter designed to be used over a guidewire It is not commonly known that the first successful static balloon dilation of the pulmonary valve, as we now know the technique, was performed in an English bulldog in 1980,65 prior to the first report of the successful procedure in 1982 in a child.66 Since it was first performed, the technique has rapidly become the treatment of choice for pulmonary valvar stenosis Apart from improvements in the design of balloon angioplasty catheters and guidewires to improve the profile and tracking ability of the products, the procedural technique has not changed significantly since its inception Only one other interventional technique was reported to treat pulmonary stenosis This involved an endovascular device with an extendable double blade designed to be extended in the pulmonary trunk and drawn back through the pulmonary valve to disrupt the stenosed leaflets.67 After the first report of three children treated in Shanghai, no further report has been published in the literature More recently, transcatheter pulmonary valve implantation has been advocated for selected patients with refractory valvar pulmonary stenosis.68 Indications Indications for intervention in children are widely discussed in the literature, with equally wide variability in the criteria for selection The indications for catheter intervention should be similar to the indications for a surgical approach, and―because of the less invasive, expensive, and time-consuming advantages of catheter intervention―this technique remains the first choice in all centers Historically, most groups would intervene if the echocardiographically derived peak instantaneous gradient across the pulmonary valve were in excess of 64 mm Hg, correlating with a Doppler velocity of more than 4 ms–1, whereas other groups have recommended a threshold of a peak instantaneous pressure gradient of greater than 50 mm Hg69 when cardiac output is normal In patients in acute or chronic heart failure, the capacity of the ventricle to generate higher pressures is impaired, cardiac output is reduced, and a lower threshold for intervention must be applied The most recent American Heart Association recommendations (Box 42.2) list critical valvar pulmonary stenosis present at birth, valvar pulmonic stenosis with a peak instantaneous gradient greater than 40 mm Hg, as well as clinically significant valvar obstruction in the presence of right ventricular dysfunction as class I indications for transcatheter balloon pulmonary valvuloplasty.70 Box 42.2 Recommendations for Pulmonary Valvuloplasty Class I Pulmonary valvuloplasty is indicated for a patient with critical valvar pulmonary stenosis (defined as pulmonary stenosis present at birth with cyanosis and evidence of patent ductus arteriosus dependency), valvar pulmonic stenosis, and a peak-to-peak catheter gradient or echocardiographic peak instantaneous gradient of >40 mm Hg or clinically significant pulmonary valvar obstruction in the presence of right ventricular (RV) dysfunction (Level of Evidence: A) Class IIA It is reasonable to perform pulmonary valvuloplasty on a patient with valvar pulmonic stenosis who meets the previously described criteria in the setting of a dysplastic pulmonary valve (Level of Evidence: C) 2 It is reasonable to perform pulmonary valvuloplasty in newborns with pulmonary valve atresia and an intact ventricular septum who have a favorable anatomy that excludes RV-dependent coronary circulation (Level of Evidence: C) Class IIB Pulmonary valvuloplasty may be considered as a palliative procedure in a patient with complex cyanotic coronary heart disease, including some rare cases of tetralogy of Fallot (Level of Evidence: C) Class III Pulmonary valvuloplasty should not be performed in patients with pulmonary atresia and RV-dependent coronary circulation (Level of Evidence: B) From Feltes TF, Bacha E, Beekman RH 3rd et al Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association Circulation 2011;123(22):2607–2652 Although some attention has been paid to intervention in milder cases, the evidence for progression of mild stenosis is lacking41 and follow-up can easily determine the cases that do progress, with the option to plan an intervention still available even up to adult life.71–75 In adults with moderate to severe stenosis, signs such as persistent exercise intolerance, pressure overload, and the risk of right ventricular fibrosis are good indications for intervention69,74 despite the usual lack of symptoms Infants presenting in the neonatal period with moderate or severe stenosis, especially those presenting with a duct-dependent pulmonary circulation, should be treated urgently.76–79 Standard Technique The standard setup for transcatheter balloon pulmonary valvuloplasty is not dissimilar to that employed for most cardiac catheterization procedures performed in patients with congenital heart disease (see Chapters 17 and 18) Fig 42.29 depicts the standard procedural stages of balloon pulmonary ... From Feltes TF, Bacha E, Beekman RH 3rd et al Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association Circulation