The aortic valve área
Echocardiogram is the main imaging tool to establish the presence, severity and repercussion of heart valve diseases.
In aortic stenosis, it makes it possible to identify the morphological lesion of the valve, for example, bivalvular or trivalvular, to estimate the impact of this stenosis by analyzing the transvalvular gradients and defining the valve area.
The latter deserves important consideration: the measurement of the valve area measured by the echocardiogram is not the anatomical measurement, but the effective flow orifice. This value is obtained by the mass conservation principle. The orifice is calculated based on the volume ejected from the left ventricle and the gradient generated between the ventricle and the aorta. Such a measure concept is necessary for a number of reasons, such as the ease and reproducibility of this measure and its efficiency in establishing the risk of patients.
Direct measurement of the valve area using two-dimensional or even three-dimensional echocardiographic images are exceptional situations. The stenotic aortic valve is most often accompanied by calcification of its leaflets, which causes difficulties for the direct calculation of the valve area.
Even today, there is a concept of requesting the measurement of the aortic valve area by direct planimetry of the orifice, especially when there is a discrepancy between the values of the valve gradients and the area of the aortic valve. National and international recommendations are very clear in recommending this situation as alternative measures, due to the lack of accuracy of the measure, either due to the presence of inappropriate images, or due to disagreement with the effective flow orifice (the anatomical area is larger than the effective flow orifice) that guide the guidelines.
1 – Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2017 Jun 20;135(25):e1159-e1195.
2 – Baumgartner H, Falk V, Bax JJ, et al; ESC Scientific Document Group. 2017 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2017 Sep 21;38(36):2739-2791.
3 – Tarasoutchi F, Montera MW, Ramos AIO, et al. Atualização das Diretrizes Brasileiras de Valvopatias: Abordagem das Lesões Anatomicamente Importantes. Arq Bras Cardiol. 2017;109(6 suppl 2):1-34.