Aortic annulus measurement and relevance to successful transcatheter aortic valve replacement: a new technique using 3D TEE.

Background: There are limitations of using 2D imaging to accurately size the aortic annulus. This article highlights the limitations of 2D technology and proposes a new 3D TEE method for sizing of the aortic annulus.

Methods: Three-dimensional echocardiography with the method described can identify the "true" aortic annulus with precision. A 3D dataset of the aortic annulus is collected. The 3D quantification program is then activated. The three multiplanar reconstruction planes (the aortic short-axis, long-axis, and coronal planes) are aligned during systole, to obtain the 3 nadirs of the sinuses of Valsalva simultaneously in the short-axis MPR. Rotating the sagittal and coronal planes to identify the hinge points is necessary to measure the diameter of the "true" annulus. The "true" aortic annulus is defined by the blood-tissue interface in the aortic short-axis MPR.

Results: This method has been prospectively validated with surgical AVR sizing in a small study of 10 patients. During surgical AVR, the annulus was directly measured using a sizer. This served as a gold standard for comparison. The annulus was measured using the method described in a blinded fashion by the cardiac anesthesiologist and then confirmed offline by a blinded echocardiographer. In this small study, the Pearson correlation coefficient was 0.9833 with 23.4 and 23.22 mm being the mean measurements with the 2 methods.

Discussion: The method described in this article is complementary to multidetector computed tomography and provides a real-time measurement of the annulus during the TAVR procedure without need for radiographic contrast.