Background— Recent studies and current clinical observations suggest that some patients with severe aortic stenosis on the basis of aortic valve area may paradoxically have a relatively low gradient despite the presence of a preserved left ventricular (LV) ejection fraction. The objective of the present study was to document the prevalence, potential mechanisms, and clinical relevance of this phenomenon. Methods and Results— We retrospectively studied the clinical and Doppler echocardiographic data of 512 consecutive patients with severe aortic stenosis (indexed aortic valve area ≤0.6 cm 2 · m −2 ) and preserved LV ejection fraction (≥50%). Of these patients, 331 (65%) had normal LV flow output defined as a stroke volume index >35 mL · m 2 , and 181 (35%) had paradoxically low-flow output defined as stroke volume index ≤35 mL · m −2 . When compared with normal flow patients, low-flow patients had a higher prevalence of female gender ( P <0.05), a lower transvalvular gradient (32±17 versus 40±15 mm Hg; P <0.001), a lower LV diastolic volume index (52±12 versus 59±13 mL · m −2 ; P <0.001), lower LV ejection fraction (62±8% versus 68±7%; P <0.001), a higher level of LV global afterload reflected by a higher valvulo-arterial impedance (5.3±1.3 versus 4.1±0.7 mm Hg · mL −1 · m −2 ; P <0.001) and a lower overall 3-year survival (76% versus 86%; P =0.006). Only age (hazard ratio, 1.04; 95% CI, 1.01 to 1.08; P =0.025), valvulo-arterial impedance >5.5 mm Hg · mL −1 · m −2 (hazard ratio, 2.6; 95% CI, 1.2 to 5.7; P =0.017), and medical treatment (hazard ratio, 3.3; 95% CI, 1.8 to 6.7; P =0.0003) were independently associated with increased mortality. Conclusion— Patients with severe aortic stenosis may have low transvalvular flow and low gradients despite normal LV ejection fraction. A comprehensive evaluation shows that this pattern is in fact consistent with a more advanced stage of the disease and has a poorer prognosis. Such findings are clinically relevant because this condition may often be misdiagnosed, which leads to a neglect and/or an underestimation of symptoms and an inappropriate delay of aortic valve replacement surgery.

Prosthesis-patient mismatch is present when the effective orifice area of the inserted prosthetic valve is less than that of a normal human valve. This is a frequent problem in patients undergoing aortic valve replacement, and its main hemodynamic consequence is the generation of high transvalvular gradients through normally functioning prosthetic valves. The purposes of this report are to present an update on the concept of aortic prosthesis-patient mismatch and to review the present knowledge with regard to its impact on hemodynamic status, functional capacity, morbidity and mortality. Also, we propose a simple approach for the prevention and clinical management of this phenomenon because it can be largely avoided if certain simple factors are taken into consideration before the operation.

Reduced SAC is a frequent occurrence in elderly patients with AS, where it independently contributes to increased afterload and decreased LV function. Systemic arterial compliance should be taken into consideration when evaluating these patients with regard to diagnosis and treatment.

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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.

Elevated Lp(a) and OxPL-apoB levels are associated with faster AS progression and need for aortic valve replacement. These findings support the hypothesis that Lp(a) mediates AS progression through its associated OxPL and provide a rationale for randomized trials of Lp(a)-lowering and OxPL-apoB-lowering therapies in AS. (Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin [ASTRONOMER]; NCT00800800).

Paradoxical low flow, low gradient, severe aortic stenosis (AS) despite preserved ejection fraction is a recently described clinical entity whereby patients with severe AS on the basis of aortic valve area have a lower than expected gradient in relation to generally accepted values. This mode of presentation of severe AS is relatively frequent (up to 35% of cases) and such patients have a cluster of findings, indicating that they are at a more advanced stage of their disease and have a poorer prognosis if treated medically rather than surgically. Yet, a majority of these patients do not undergo surgery likely due to the fact that the reduced gradient is conducive to an underestimation of the severity of the disease and/or of symptoms. The purpose of this article is to review and further analyse the distinguishing characteristics of this entity and to present its implications with regards to currently accepted guidelines for AS severity.

Increased Z(va) is a marker of excessive LV hemodynamic load, and a value >3.5 successfully identifies patients with a poor outcome. These findings suggest that beyond standard indexes of stenosis severity, the consideration of Z(va) may be useful to improve risk stratification and clinical decision making in patients with AS.