Abstract
Aortic stenosis is the most common primary heart valve disease in adults and an important cause of cardiovascular morbidity and mortality. Up to 40% of patients with aortic stenosis have discordant Doppler-echocardiographic findings, the most common of which is the presence of a small aortic valve area (<= 1.0 cm2) suggesting severe aortic stenosis, but a low gradient (< 40 mmHg) suggesting nonsevere aortic stenosis.
In clinical practice, three subpopulations of patients with severe aortic stenosis and low gradient are distinguished: a/ "classical" type with a low gradient, low flow and low left ventricular ejection fraction: b/ paradoxical type with low gradient, low flow and preserved ventricular ejection fraction and c/ patients with a low gradient, normal flow, and normal ejection fraction. Echocardiography is the key tool for the diagnosis and evaluation of aortic stenosis.
However, confirmation of the presence of aortic stenosis is particularly challenging in these patients and requires a multimodality imaging, such as low dose dobutamine stress test and aortic valve calcium scoring by multidetector computed tomography. Intervention of severe aortic stenosis should be considered despite a very high operative risk in these subgroups.
Transcatheter aortic valve implantation may be superior to surgical aortic valve replacement especially in patients with low-flow, low gradient aortic stenosis.