Natural Progression of Low-Gradient Severe Aortic Stenosis with Preserved Ejection Fraction

Abstract

Because the natural progression of low-gradient aortic stenosis (LGAS) has not been well defined, we performed a retrospective study of 116 consecutive patients with aortic stenosis who had undergone follow-up echocardiography at a median interval of 698 days (range, 371-1,020 d I n the western world, aortic stenosis (AS) is the most prevalent valvular heart disease and the 3rd most prevalent cardiovascular disease, after hypertension and coronary artery disease.1 The prevalence of AS increases with age, from 2% of adults older than 65 years to 4% of adults older than 85.2 As the average lifespan increases, the burden of senile AS is expected to increase. Aortic stenosis is a progressive condition in which patients are often asymptomatic for years. 3 The duration of the asymptomatic phase can vary widely among individuals. After the onset of symptomic heart failure, only 50% will survive longer than 2 years without valve replacement. 4 Although sudden cardiac death is a frequent cause of death in symptomatic patients, it appears to be rare (<1% per year) in asymptomatic patients. [5][6][7] Close monitoring and aortic valve replacement surgery (when patients become symptomatic) remain the standard of care. 8,9 Current American and European guidelines define severe AS as an aortic valve area (AVA) of <1 cm 2 or, indexed by body surface area, <0.6 cm 2 /m 2 . 8,10 The corresponding values are a peak aortic valve velocity of 4 m/s and a mean aortic valve pressure gradient (MG) of ≥40 mmHg in the presence of normal cardiac output-that is, normal left ventricular ejection fraction (LVEF). Moderate stenosis is characterized by an AVA of 1 to 1.5 cm 2 and an MG of 25 to 40 mmHg. However, not all patients fall into these specific categories of moderate or severe AS as determined by both AVA and MG. Approximately one third of patients sent for echocardiographic evaluation of the severity of AS show a discrepancy in echocardiographic measurements: severe stenosis on the basis of AVA, but non-severe stenosis on the basis of MG, in the presence of a normal LVEF. 11,12 These discrepancies were at first attributed to inaccuracies in echocardiographic measurements and to interobserver variability.In the past few years, increasing data have suggested that patients with normal LVEF in the presence of severe AS as defined by valve area (AVA, <1 cm 2 ) and low valve gradient (MG, <40 mmHg) form a true subgroup. These results appear not to be an anomaly arising from the misreading of echocardiographic measure-

Echocardiographic findings on aortic stenosis: an observational, prospective, and multi-center registry

“…A similar retrospective study 10 of 116 consecutive patients with aortic stenosis who had undergone follow-up echocardiography at a median interval of 698 days, described an annual change of aortic valve area (AVA) and mean gradient (MG) for the entire cohort was −0.09 ± 0.14 cm 2 (decrease in AVA) and 2 ± 6 mmHg (increase in MG). They also concluded LG AS probably represents an intermediate stage between moderate AS and severe AS with normal EF.…”

“…They also concluded LG AS probably represents an intermediate stage between moderate AS and severe AS with normal EF. 10 TOPAS study stresses the importance of contractile reserve study in LFLG patients. 11…”

Transtoracical Ecocardiographic Assessment of Severe Degenerative Aortic Stenosis with Normal Ejection Fraction and Low Transvalvular Gradient

“…Degenerative aortic stenosis is defined by Catherine Otto [1] as a slowly evolving disorder, which induces negative hemodynamic effects and causes symptoms by progressive obstruction of the left ventricular ejection tract. According to the current statistical data [2,3], after 65 years of age, 2% of the population presents aortic stenosis by valvular calcification and 30% aortic sclerosis, this being defined as an irregular thickening of the aortic valves, detected echocardiographically, without significant limitation of the mobility of the cusps. After 90 years the prevalence of aortic stenosis is 9.8%.…”

“…The literature [3,[22][23][24][25][26][27][28][29] describes the existence in the group of severe aortic stenosis with preserved ejection fraction, of a subgroup of patients with aortic orifice area less than 1cm 2 , but who present maximal transvalvular systolic velocities lower than 4 m/s at the echocardiographic evaluation. According to these studies, the explanation of the phenomenon would mainly consist of the existence of important concentric left ventricular hypertrophy that associates a small ventricular cavity and a low systolic flow.…”