Abstract 536: Evaluation of Left Ventricular Outflow Tract Eccentricity in Patients With Aortic Valve Sclerosis Using 64-multidetector Computed Tomography: Comparison With Two-Dimensional Echocardiography
Background: Estimating the aortic valve area (AVA) using the continuity equation (CE) is routinely essential to assess severity of calcified aortic valve disease. In the CE, calculated AVA is greatly affected by small changes of the left ventricular outflow tract (LVOT) diameter because LVOT area is determined by assuming circular geometry. Recently, multidetector computed tomography (MDCT) can provide insight into cardiac geometry from views previously unobtainable. We aimed to evaluate LVOT eccentricity using MDCT.
Methods: A total of 69 patients (mean age 71 years) with aortic valve sclerosis (AVS) underwent 64-MDCT and 2DE. The diameter-derived LVOT area (Adiam) was calculated by 2DE from a parasternal long axis view. The LVOT area with MDCT (Aplan) was estimated by quantitative planimetry just beneath the aortic valve in a plane perpendicular to the LVOT long axis using the double-oblique method. Furthermore, we measured the short (a) and long (b) diameters of the planimetered LVOT view, and ellipsoidal-estimated LVOT area (Aellip) was calculated using πab. Eccentricity index (EI) was estimated by 1−a/b.
Results: Aplan (range, 315– 650 mm2) always measured larger than Adiam (mean 445 ± 77 vs. 380 ± 68 mm2, p < 0.001). Mean EI was 0.20 ± 0.04 (95%CI 0.19 – 0.21, p < 0.001) and EI was independent of Aplan, AVA, age, body size, and cardiac geometry. Aplan was more related to Aellip (r = 0.97, p < 0.001) than Adiam (r = 0.79, p < 0.001). In addition, Aplan correlated positively with AVA (r = 0.61, p < 0.001).
Conclusion: The LVOT was not circular but elliptical in patients with AVS. LVOT eccentricity should be considered when estimation of AVA is calculated by CE because of underestimated LVOT area.