Morphometric Analysis of Aortic Coarctation Determination of the Target Vessel Diameter Required to Relieve the Pressure Gradient

BACKGROUND: Little is known about the precise morphometric data of the aortic arch at which the transcatheter pressure gradient is relieved in patients with aortic coarctation (CoA). METHODS AND RESULTS: Twenty-nine morphometric data were obtained from patients with CoA including the body surface area (BSA) adjusted angiographic diameter of the narrowest vessel, the ratio of the angiographic diameter to that of the descending aorta and BSA-adjusted narrowest cross-sectional area (CSA) using intravascular ultrasound imaging. The transcatheter peak-to-peak pressure gradient of the aortic arch was measured using a manometer tipped catheter. A linear regression analysis showed CSA to have the strongest correlation with the pressure gradient (r=0.92, p=0.0002) among any pressure gradient group (n=10). A receiver-operating characteristic curve (ROC) analysis was performed to determine the morphometric cut-off point at which the pressure gradient occurs. CSA had the highest areas under the ROC (1.0) and the cut-off point of 81 mm2/m2 showed a sensitivity of 100% and specificity of 100% to predict the relief of a pressure gradient. CONCLUSIONS: In patients with CoA, the vessel size that can relieve a pressure gradient is a CSA of 81 mm2/m2 (10 x BSA0.5 mm in diameter). This data may provide useful information for catheter intervention and surgery.