Catheter-Based Therapies for Adult Congenital Heart Disease

Balloon Valvuloplasty

Percutaneous balloon valvuloplasty is a commonly performed procedure for congenital semilunar valve stenosis early in life, but in adults, the disease is usually mild or has been successfully treated. Occasionally, adults may require intervention due to hemodynamic changes secondary to calcific degeneration or long-standing burden of disease.

Balloon pulmonary valvuloplasty is performed using a balloon diameter 20% to 30% greater than the diameter of the valve annulus, or if the annulus is large, two balloons may be used simultaneously ( Fig. 52.2 ). Unless there is severe valve dysplasia, calcification, or annular hypoplasia, this technique is highly successful, durable, and has replaced surgical intervention in most cases. Residual gradients are typically <20 mm Hg, with mild nonprogressive pulmonary regurgitation. In selected neonates, the procedure is used to treat pulmonary atresia with an intact ventricular septum after initial radiofrequency perforation of the atretic valve membrane.

Bicuspid aortic valve is the most common congenital heart malformation. When significant commissural fusion and leaflet thickening are associated, the severity of stenosis often justifies intervention early in life, and balloon valvuloplasty can delay valve replacement surgery for decades. Avoidance of a prosthetic valve and associated anticoagulation is particularly appealing during the years of athletic participation and childbearing. When significant calcific degeneration is associated late in life, surgical valve replacement or transcatheter aortic valve replacement is preferred therapy. Balloon aortic valvuloplasty is performed with a balloon to valve annulus diameter ratio of 0.9 to 1.0. In teenagers and young adults, the large valve annulus often requires the double balloon technique (sum of balloon diameters/annulus ratio ~ 1.3) assisted by rapid pacing ( Fig. 52.3 ). Gradient reductions of 50% to 70% are typical, usually with a well-tolerated degree of aortic regurgitation. Less than one-half of patients will require surgical aortic valve replacement within 10 years of follow-up.

Transcatheter Pulmonary Valve Implantation

Many surgical repairs (e.g., for pulmonary atresia, truncus arteriosus, the Rastelli repair for complex transposition of the great arteries, and the Ross pulmonary autograft procedure for aortic valve disease) require placement of a right ventricular to pulmonary artery conduit. Tetralogy of Fallot repair results in residual pulmonary valve dysfunction. Long-standing residual pulmonary valve or conduit dysfunction leads to late complications, namely, right ventricular failure and life-threatening arrhythmias. Repeated surgical replacement of conduits carries morbidity, has limited durability, and confers a cumulative risk of late arrhythmogenic death. Transcatheter implantation of a pulmonary valve produces an excellent hemodynamic result in most cases, allows a delay in surgical intervention, and minimizes the number of surgical procedures in the lifetime of a patient. Two transcatheter valves have received Food and Drug Administration approval in the United States, the Medtronic Melody valve (Medtronic, St. Paul, Minnesota) and the Edwards Sapien valve (Edwards Lifesciences, Irvington, California) ( Video 52.2 ). Because the routine practice of prestenting has been adopted, the early problems of stent fracture and restenosis are now rare, and freedom from reintervention for the Melody valve is 89% at 7 years of follow-up. These valves are indicated for patients with a preexisting surgically implanted dysfunctional conduit (>16 mm) or bioprosthetic valve, but occasional patients with repaired tetralogy of Fallot and an intact pulmonary annulus (<24 mm) may be considered.