Diagnostic evaluation of low-flow, low-gradient aortic stenosis requires distinguishing true severe from pseudosevere stenosis in depressed LVEF and identifying restrictive physiology in normal LVEF.
This review outlines the diagnostic and therapeutic management of low-flow, low-gradient aortic stenosis, emphasizing the importance of distinguishing true severe from pseudosevere stenosis and recognizing paradoxical LF-LG severe AS.
Low-flow, low-gradient (LF-LG) aortic stenosis (AS) may occur with depressed or preserved left ventricular ejection fraction (LVEF), and both situations are among the most challenging encountered in patients with valvular heart disease. In both cases, the decrease in gradient relative to AS severity is due to a reduction in transvalvular flow. The main challenge in patients with depressed LVEF is to distinguish between true severe versus pseudosevere stenosis and to accurately assess the severity of myocardial impairment. Paradoxical LF-LG severe AS despite a normal LVEF is a recently described entity that is characterized by pronounced LV concentric remodeling, small LV cavity size, and a restrictive physiology leading to impaired LV filling, altered myocardial function, and worse prognosis. Until recently, this entity was often misdiagnosed, thereby causing underestimation of AS severity and inappropriate delays for surgery. Hence, the main challenge in these patients is proper diagnosis, often requiring diagnostic tests other than Doppler echocardiography. The present paper proposes to review the diagnostic and therapeutic management specificities of LF-LG AS with and without depressed LV function.
“I don't know why, but we're seeing more and more of these patients. I think 10 years ago we just kind of ignored them. We thought we'd made a mistake in our calculations. But in fact if you're very meticulous about your calculations, 30%-40% of your aortic stenosis patients fit into this category.”
Pîbarot et al. (2012) conducted a review in Low-flow, low-gradient aortic stenosis. Diagnostic evaluation of low-flow, low-gradient aortic stenosis requires distinguishing true severe from pseudosevere stenosis in depressed LVEF and identifying restrictive physiology in normal LVEF.