Abstract 9937: Comparison of Aortic Root Dimensions using Multi Slice Computer Tomography and 2D Transthoracic Echocardiography. CARDIA Study

Abstract

Introduction: Multislice computer tomography (MSCT) is the gold standard for measuring aortic root dimensions; however, in clinical practice 2D transthoracic echocardiography (2DTE) is commonly used to diagnose and monitor aortic root diseases. Limited data exist on the accuracy of the 2DTE approach. We assessed the agreement between MSCT and 2DTE dimensions of the aortic root in middle-aged adults free of clinical aortic diseases who were part of the ongoing Coronary Artery Risk Development in Young Adults (CARDIA) Study. Methods: 2DTE and MSCT were used to measure the aortic root dimensions in 1197 CARDIA participants. The MSCT aortic root dimension was measured on non-contrast enhanced images using 0.5-0.6mm slices reformatted to provide true cross sections perpendicular to the vessel centerline, 3 D Slicer® (planimetered: [ROI pixel count multiplied by unit pixel area]) while the 2DTE aortic root diameter was measured by leading-edge to leading-edge approach [MM mode, Parasternal long axis with aorta and left atrium in view] and the area obtained using π r2. Correlation coefficient and Bland Altman plots were used to assess the agreement between the 2 approaches. Results: Mean age 49.9 ±3.6 yrs, BMI 30.5 ±7.1 kg/m2, LDL-C 110.3 ±33.5 mg/dL, HDL-C 57.3 ±17.4 mg/dL, 52.9% blacks, 45.6% males, 11.1% diabetics, 39.3% former/current smokers and 35.4% had hypertension. Prevalence of aortic root dilation (>4cm) was 1.7% by MSCT and 2.1% by 2DTE. The mean aortic root diameter and area by 2DTE and 3 D slicer® were 3.07 ±0.42 cm and 3.02± 0.33 cm; 8.3± 1.7 cm2 and 7.5 ±2.1 cm2 respectively. The aortic root diameters/ areas by the 2 approaches had a Pearson correlation coefficient of 0.67. In the Bland Altman analysis the bias and limits of agreement for aortic root diameter and area were -0.15 and -0.80 to 0.48 cm; -0.57 and -3.8 to 2.7cm2 respectively. The sensitivity, specificity, PPV and NPV of 2DTE for diagnosing aortic root dilation were 0.43 (0.22 to 0.66), 0.98 (0.976 to 0.991), 0.33 (0.17 to 0.54) and 0.99 (0.982 to 0.995) respectively. Conclusions: The accuracy of 2DTE for aortic root dimensions shows moderate agreement with the MSCT suggesting that there will often be disagreement between these 2 approaches which would have significant clinical and cost implications.