From the Guidelines

A DVI of 0.53 is indicative of moderate aortic stenosis, as values between 0.5 and 0.7 are consistent with this diagnosis 1.

The DVI is calculated as the ratio of the left ventricular outflow tract velocity to the aortic valve velocity, with normal values being greater than 0.5.
A DVI between 0.25 and 0.5 typically suggests severe aortic stenosis, while values between 0.5 and 0.7 are consistent with moderate stenosis.
At 0.53, the patient falls into the moderate category, though at the more severe end of this range.

This finding should be interpreted alongside other echocardiographic parameters such as mean gradient, valve area, and peak velocity for a comprehensive assessment.
According to the 2020 ACC/AHA guideline for the management of patients with valvular heart disease, mean pressure gradient is a strong predictor of outcome after AVR, with better outcomes seen in patients with higher gradients 1.

Patients with moderate aortic stenosis generally require regular monitoring with echocardiography every 1-2 years to assess for disease progression, though more frequent monitoring may be warranted if the patient is symptomatic or if the DVI is borderline between moderate and severe.
Clinical correlation is essential, as symptoms such as exertional dyspnea, angina, or syncope may indicate a need for intervention even with moderate stenosis by echocardiographic criteria, as highlighted in the guideline 1.

The guideline also notes that disease progression occurs in nearly all patients with severe asymptomatic AS, and symptom onset within 2 to 5 years is likely when aortic velocity is ≥4.0 m/s or mean pressure gradient is ≥40 mm Hg 1.
Therefore, close monitoring and a comprehensive assessment are crucial in managing patients with aortic stenosis, regardless of the severity.

From the Research

The severity of aortic stenosis can be assessed using the Doppler Velocity Index (DVI) 2, 3.
A DVI of 0.53 is lower than the normal range for a prosthetic valve (DVI >0.35) but higher than the threshold for severe aortic stenosis (DVI ≤0.25) 3.
According to the study by 3, a DVI ratio ≤0.24 is associated with severe aortic stenosis, and a slight lowering of the recommended TTE-derived DVI threshold for severe AS from 0.25 to 0.24 improved the ability to discriminate moderate versus severe AS.
However, the study by 2 suggests that DVI <0.50 is associated with poor outcomes following transcatheter aortic valve replacement (TAVR), but it does not provide a specific threshold for severe aortic stenosis.
Based on the available evidence, a DVI of 0.53 would likely indicate moderate to severe aortic stenosis, but the exact severity would depend on other factors such as the patient's symptoms, left ventricular function, and valve morphology 3, 4, 5, 6.

The severity of aortic stenosis can be influenced by various factors, including the patient's age, comorbidities, and left ventricular function 4, 5.
Renin-angiotensin system (RAS) blockade therapy has been shown to modulate adverse left ventricular remodeling and reduce myocardial hypertrophy and fibrosis in patients with aortic stenosis 5.
Antihypertensive treatment with β-blockade has been associated with lower risk of cardiovascular events in patients with asymptomatic mild to moderate aortic stenosis 6.
However, the relationship between these factors and DVI is not well established, and further studies are needed to determine the optimal management strategy for patients with aortic stenosis 2, 3, 4, 5, 6.