Abstract
Staging based on extra-valvular cardiac damage is an intuitive approach to categorizing patients with aortic stenosis (AS) that is easily applied using widely available echocardiographic tools. As discussed in this review, it has been shown to be a powerful tool for risk stratification that complements conventional approaches. The original and most widely used framework identifies stage 0 when there is AS without additional cardiac damage; stage 1 when there is left ventricular damage (hypertrophy, systolic or diastolic dysfunction with evidence of elevated filling pressures); stage 2 when there is mitral dysfunction (moderate or greater mitral regurgitation, typically secondary) or left atrial abnormalities (left atrial enlargement or atrial fibrillation); stage 3 when there is pulmonary hypertension and/or moderate or greater tricuspid regurgitation (typically secondary); and stage 4 when there is moderate or greater right ventricular dysfunction. In a series of studies that have collectively evaluated damage before and after aortic valve replacement in patients with moderate and severe AS, as well as with and without symptoms, cardiac damage has been shown to predict all-cause and cardiovascular mortality and other outcomes. These observations support the design of trials to reevaluate thresholds for aortic valve replacement in AS and approaches that consider cardiac damage stage in clinical decision-making for individual patients (valve replacement vs. medical therapy).