Low-flow low-gradient aortic stenosis in patients with low ejection fraction: But is the flow truly low?

摘要

It is known that judging the severity of aortic stenosis (AS) in patients with co-existent left ventricular (LV) systolic dysfunction can be challenging. These patients are particularly difficult for the managing clinician as their operative risk is high but outcome with medical therapy is poor. Quantitative Doppler echocardiography permits calculation of the aortic valve area (AVA), which may be < 1.0 cm2 despite a low peak velocity and low mean pressure gradient. This widely accepted concept, first described over three decades ago [1], is termed low-flow low-gradient aortic stenosis (LFLG AS).In 1995, the use of dobutamine echocardiography (DbE) was first reported for helping to differentiate true severe AS from pseudo-severe AS [2], in which reduced systolic cusp excursion is secondary to depressed myocardial function. The theory underpinning the use of DbE was to augment systolic function and, thereby, permit re-evaluation of Doppler parameters with an increased stroke volume.-The current American [3] and European [4] guidelines on valvular heart disease both state that DbE may be helpful in the evaluation of patients with LFLG AS.