Cardiac Magnetic Resonance to Evaluate Percutaneous Pulmonary Valve Implantation in Children and Young Adults.

Experience with cardiac magnetic resonance to evaluate coronary arteries in children and young adult patients is limited. Because noninvasive imaging has advantages over coronary angiography, we compared the effectiveness of these techniques in patients who were being considered for percutaneous pulmonary valve implantation. We retrospectively reviewed the cases of 26 patients (mean age, 12.53 ± 4.85 yr; range, 5-25 yr), all of whom had previous right ventricular-to-pulmonary artery homografts. We studied T2-prepared whole-heart images for coronary anatomy, velocity-encoded cine images for ventricular morphology, and function- and time-resolved magnetic resonance angiographic findings. Cardiac catheterization studies included coronary angiography, balloon compression testing, right ventricular outflow tract, and pulmonary artery anatomy. Diagnostic-quality images were obtained in 24 patients (92%), 13 of whom were considered suitable candidates for valve implantation. Two patients (8%) had abnormal coronary artery anatomy that placed them at high risk of coronary artery compression during surgery. Twelve patients underwent successful valve implantation after cardiac magnetic resonance images and catheterization showed no increased risk of compression. We attempted valve implantation in one patient with unsuitable anatomy but ultimately placed a stent in the homograft. Magnetic resonance imaging of coronary arteries is an important noninvasive study that may identify patients who are at high risk of coronary artery compression during percutaneous pulmonary valve implantation, and it may reveal high-risk anatomic variants that can be missed during cardiac catheterization.