A 31-year-old man is referred for evaluation of severe pulmonary regurgitation. He has a history of tetralogy of Fallot with AV canal defect, initially repaired at the age of 9 months, with transannular patch enlargement of the right ventricular outflow tract (RVOT) and main pulmonary artery. He subsequently developed severe RVOT obstruction and underwent a total of 4 redo surgical patch repairs of the RVOT by the age of 8 years. At the age of 29, he was medically treated for Staphylococcus endocarditis of the pulmonary valve. Now at the age of 31, routine surveillance transthoracic echocardiography demonstrates severe pulmonary regurgitation (Figures 25-1 and 25-2), moderate pulmonary stenosis (Figure 25-2), and a moderately enlarged but normally functioning right ventricle in the setting of decreasing exercise tolerance. He is referred for consideration of transcatheter pulmonary valve implantation.
Two-dimensional echocardiography with color Doppler, short axis at the base, demonstrating severe pulmonary regurgitation. (Reproduced, with permission, from Vaikom S. Mahadevan, MD.)
Continuous-wave Doppler echocardiography across the pulmonary valve demonstrates severe pulmonary regurgitation with a short pressure half-time and moderate pulmonary stenosis with a peak velocity near 3 m/s. (Reproduced, with permission, from Vaikom S. Mahadevan, MD.)
ETIOLOGY AND PATHOPHYSIOLOGY
It is estimated that nearly 1 million adults in the United States are living with congenital heart disease (CHD).1 Although many of these patients have undergone corrective or palliative surgical procedures early in life, they often have the sequelae of their disease and require repeat cardiac procedures over their lifetime. Lesions causing RVOT dysfunction are an important subset of CHD and include primary pulmonary valve dysfunction, supravalvular stenosis, and subvalvular stenosis mainly due to infundibular or subinfundibular stenosis. RVOT obstruction is a hallmark of tetralogy of Fallot (TOF), the most common form of cyanotic heart disease after the age of 1 year, with an incidence of approximately 10% of all CHD.2 Treatment for RVOT obstruction and TOF has advanced dramatically over the past 7 decades. Prior to the first palliative systemic-pulmonary shunt operation by Blalock and Tausig in 1945, TOF was nearly universally fatal. In the mid 1950s, the first successful intracardiac repair of TOF took place at the University of Minnesota, reducing the mortality rate from 50% to <2%.3 Complete intracardiac repair is currently accomplished by (1) widening of the RVOT with preservation of the native pulmonic valve or replacing the RVOT using a surgical valved conduit with a homograft or bioprosthetic pulmonary valve, and (2) placing a patch over the ventricular septal defect to eliminate shunting at the ventricular level and redirect the aortic override. With modern operative repair, most patients with TOF live well into adulthood, but the majority will continue to experience residual hemodynamic ...