Low Gradient Severe Aortic Stenosis With Preserved Ejection Fraction: Don't Forget the Flow! Estenosis aortica grave con bajo gradiente y fraccion de eyeccion preservada: no olvidemos el flujo

reported the results of a study that examined whether severe aortic stenosis (AS) with low-gradient and preserved ejection fraction is a real phenomenon or whether it corresponds to an error in measurement. As they appropriately emphasize in their introduction, most cardiologists now recognize that this mode of presentation is frequently encountered during echocardio- graphic examinations. Also, several studies have reported that this entity is a more advanced form of the disease and has a worse prognosis. In contrast, a recent prospective study suggested that prognosis in these cases is similar to moderate AS and that this subcategory of patients probably reflects an error in classifica- tion. To answer this question, Gonzalez-Canovas et al. 1 examined 63 patients with paradoxical low-gradient AS and found that aortic valve area (AVA) measured by 3-dimensional (3D) aortic valve planimetry was congruent with that obtained by trans- thoracic echocardiography (TTE) using the continuity equation; the presence of severe AS was confirmed in 85% of patients. They hence concluded that paradoxical low-gradient severe AS is a real entity. These results are important and we would like to make a few observations so that these results may be interpreted in the right context.