Paradoxical aortic stenosis: much more than a classification problem

Aortic stenosis (AS) is the most frequent valvular pathology and is one of the most common indications of valve replacement surgery. Its main form of presentation is calcified AS, whose prevalence increases proportionally with age. The indication of aortic valve replacement (AVR) is clear when the echocardiographic parameters of severity are coincident with each other and the patient presents symptoms, deterioration of the left ventricular ejection fraction (LVEF) or other indication of cardiac surgery. But with the advancement of diagnostic methods, new classifications of this condition have emerged. The term "paradoxical low-flow, low-gradient aortic stenosis" appears, which refers to the presence of an aortic valve area (AVA) <1 cm 2 or indexed AVA <0.6 cm 2 /m 2 , associated with low transvalvular flow and gradients, but with preserved LVEF (50%). This combination of data leads to a discordant classification (AVA in range of severity, medium gradient with values of mild to moderate disease). Due to the probability of potential errors that could underestimate the AVA by Doppler echo, and the uncertainty about the real meaning of this pathology, it is necessary to confirm the veracity of these findings, to give a correct diagnosis and treatment to patients with this intriguing entity.