[Paradoxical low-flow low-gradient aortic stenosis]

In approximately one third of patients presenting with suspected severe aortic stenosis, there is a discrepancy between a severely reduced aortic valve opening area (< 1 cm(2)) and a non-severe increase of the mean transvalvular gradient (< 40 mmHg). In a substantial number of these cases there is evidence of a severe paradoxical low-flow low-gradient aortic stenosis, characterized by a reduced stroke volume index in the setting of a normal left ventricular ejection fraction. This finding should trigger an extensive diagnostic work-up, including echocardiography, stress echocardiography and computed tomography to rule out measurement errors and to identify the cause(s) of the hemodynamic discrepancy. If the diagnosis of a severe paradoxical low-flow low-gradient aortic stenosis is confirmed and, furthermore, the patient is normotensive and reports stenosis-associated symptoms, the feasibility of an aortic valve replacement should be considered.