Randomized Study for the Optimal Treatment of Symptomatic Patients With Low Gradient Severe Aortic Valve Stenosis and Preserved Left Ventricular Ejection Fraction

According to current European Recommendations on valvular heart disease (VHD), "classical" severe aortic stenosis (AS) is defined by an aortic valve area (AVA) ≤1 cm2 and indexed AVA ≤0.6 cm2/m2, a mean aortic pressure gradient (MAG) >40 mmHg, and a maximal aortic velocity >4 m/sec.

Aortic valve replacement (AVR) is recommended (class I indication) in patients with "classical" severe AS who have any symptoms related to aortic valve disease.

In 2007, Hachicha et al. described a particular pattern of severe AS, characterized by an AVA ≤0.6 cm2/m2, low mean pressure aortic gradient (MAG <40 mmHg), despite the presence of a preserved left ventricular ejection fraction (LVEF ≥50%). This pattern of AS is encountered in nearly 15-25 % of patients who have severe AS. Typically, these patients are elderly subjects, with several comorbidities, a small left ventricular (LV) cavity with pronounced LV concentric remodeling and a restrictive physiology, leading to a decrease in LV stroke volume despite a preserved LVEF. The diagnosis and management of patients with low gradient severe AS and preserved LVEF are often challenging because:

1. the presence of a "true" severe aortic stenosis should be carefully confirmed by a multi-modality imaging approach;
2. the best therapeutic management (AVR versus conservative strategy) of symptomatic patients with low gradient severe AS and preserved LVEF is not clearly established.

In very recently updated European guidelines on the management of VHD, symptomatic patients with low gradient and low flow severe AS and preserved LVEF have only a class IIa-level C indication for AVR. No specific indications are given for the management of symptomatic patients with low gradient and normal flow severe AS. This lack of indications is clearly attributed to a gap in knowledge which requires further investigations to be filled up.