Magnetic resonance imaging demonstration of “Remodeling” of the aorta following balloon angioplasty of discrete native coarctation

Assessment of the hemodynamic and anatomic results following balloon angioplasty of discrete native coarctation of the aorta, with particular attention to ``remodeling,' has required repeat cardiac catheterization and angiography, which is invasive and has limited resolution. Eight patients with hypertension and discrete native coarctation with an otherwise normally developed aortic arch underwent angioplasty at 5.0 ± 6.8 years of age. Angiographic cross-sectional areas of the aorta indexed to body surface area at the isthmus (I), coarctation site (C), and 1 cm distal to the coarctation site (Cd) pre- and postangioplasty were compared with MRI-indexed cross-sectional areas 18 ± 10 months (MRI-1) and 35 ± 11 months (MRI-2) postangioplasty. From preangioplasty to MRI-2, the isthmus was smaller (149 ± 22 versus 127 ± 27 mm<sup>2</sup>/m<sup>2</sup>; p < 0.05). The coarctation site was larger postangioplasty (25 ± 9 versus 116 ± 40 mm<sup>2</sup>/m<sup>2</sup>; p < 0.001) with continued growth at latest follow-up (116 ± 40 versus 164 ± 36 mm<sup>2</sup>/m<sup>2</sup>; p < 0.01). The segment 1 cm distal to the coarctation site continued to decrease in area at latest follow-up (267 ± 78 versus 163 ± 38 mm<sup>2</sup>/m<sup>2</sup>; p < 0.001). I versus C versus Cd at MRI-2 were similar, whereas postangioplasty and MRI-1 cross-sectional area measurements were significantly different. Following angioplasty of discrete native coarctation, the aorta becomes more uniform or undergoes ``remodeling.' Noninvasive MRI is an effective means of evaluating the anatomic result following balloon angioplasty, obviating the need for repeated invasive cardiac catheterizations.