Gilda Boroumand MD, Presenter: Nothing to Disclose

Hugh White MD, Abstract Co-Author: Nothing to Disclose

Praneil Patel MD, Abstract Co-Author: Nothing to Disclose

Ethan J. Halpern MD, Abstract Co-Author: Nothing to Disclose

The shape of the left ventricular outflow tract (LVOT), aortic annulus and aortic root may impact the proper sizing of a percutaneous aortic valve replacement (TAVR). We evaluated the sphericity of left ventricular outflow with ECG-gated coronary CTA from the LVOT through the sinotubular junction in both diastole and systole.

ECG-gated CTA studies were reviewed from 52 consecutive patients with normal aortic valves and 13 TAVR candidates with severe aortic stenosis and dense valvular calcification. Using a dedicated 3D workstation, orthogonal measurements of the outflow tract were obtained to define the antero-posterior (AP) and transverse diameters (short and long axis) at 4 levels: LVOT, aortic annulus, aortic root and sinotubular junction. Sphericity was defined as the ratio of the AP to transverse diameter at each level.

Analysis of variance demonstrated that both the level of the measurement and the phase of the cardiac cycle were significantly associated with sphericity (p<0.0001), while the presence of aortic stenosis was non-significant (p=0.96). Mean sphericity during diastole measured 0.61 at the LVOT, 0.77 at the aortic annulus, 0.94 at the aortic root and 1.00 at the sinutubular junction (p<0.0001 for comparison of any two adjacent levels). During systole, mean sphericity measured 0.69 at the LVOT, 0.81 at the aortic annulus, 0.93 at the aortic root and 1.00 at the sinutubular junction (p<0.0001 for comparison of any two adjacent levels). Differences in sphericity between diastole and systole were significant at the LVOT (p<0.0001) and at the aortic annulus (p=0.0061).

The shape of the left ventricular outflow changes from an oval at the level of the LVOT to a more circular shape at the level of the sinotubular junction. Although the entire outflow tract changes in size and sphericity during the cardiac cycle, this change is most pronounced at the LVOT, and is statistically significant only at the LVOT and aortic annulus levels. The sphericity of left ventricular outflow structures and the change in sphericity during the cardiac cycle is similar among patients with a normal aortic valve and those with severe aortic stenosis.

The oval shape of the proximal left ventricular outflow is not altered by the presence of aortic stenosis and calcification. This shape may have important implications for the design and positioning of aortic valve implants.

Boroumand, G, White, H, Patel, P, Halpern, E, Morphology of Left Ventricular Outflow from the Left Ventricular Outflow Tract to the Sinotubular Junction: Comparison of Patients with Normal Aortic Valves to Those with Severe Aortic Stenosis.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14002784.html