Noninvasive Evaluation of the Aortic Root With Multislice Computed Tomography Implications for Transcatheter Aortic Valve Replacement

OBJECTIVES In the present study, the anatomy of the aortic root was assessed noninvasively with multislice computed tomography (MSCT). BACKGROUND Transcatheter aortic valve replacement has been proposed as an alternative to surgery in high-risk patients with severe aortic stenosis. For this procedure, detailed knowledge of aortic annulus diameters and the relation between the annulus and the coronary arteries is needed. METHODS In 169 patients (111 men, age 54 +/- 11 years), a 64-slice MSCT scan was performed for evaluation of coronary artery disease. Of these, 150 patients had no or mild aortic stenosis, and 19 patients had moderate to severe aortic stenosis. Reconstructed coronal and sagittal views were used for assessment of the aortic annulus diameter in 2 directions. In addition, the distance between the annulus and the ostium of the right and left coronary arteries and the length of the coronary leaflets were assessed. The LV outflow tract and interventricular septum were analyzed on the single oblique sagittal view at end-diastole. RESULTS The diameter of the aortic annulus was 26.3 +/- 2.8 mm on the coronal view, and 23.5 +/- 2.7 mm on the sagittal view. Mean difference between the 2 diameters was 2.9 +/- 1.8 mm, indicating an oval shape of the aortic annulus. Mean distance between the aortic annulus and the ostium of the right coronary artery was 17.2 +/- 3.3 mm, and mean distance between the annulus and the ostium of the left coronary artery was 14.4 +/- 2.9 mm. In 82 patients (49%), the length of the left coronary leaflet exceeded the distance between the annulus and the ostium of the left coronary artery. There were no significant differences in the diameter of annulus, diameter of sinus of Valsalva, or the distance between the annulus, left coronary leaflet, and the ostium of the left coronary artery, between the patient with and without severe aortic stenosis. CONCLUSIONS The MSCT can provide detailed information on the shape of the aortic annulus and the relation between the annulus and the ostia of the coronary arteries. Thereby, MSCT may be helpful for avoiding paravalvular leakage and coronary occlusion and may facilitate the selection of candidates for transcatheter aortic valve replacement. (J Am Coll Cardiol Img 2008; 1: 321-30) (C) 2008 by the American College of Cardiology Foundation