Mild, moderate or severe valvular heart disease:
what it means in the report

Article written and reviewed by Dr Luca Moretti

When an echocardiogram describes valvular heart disease as mild, moderate or severe, it is describing the severity of that specific valve abnormality according to echocardiographic criteria. It is not a score of the heart's overall condition and, by itself, it does not indicate how unwell a person should feel.
Severe valvular heart disease may still cause no symptoms, while a person with a mild lesion may be short of breath for completely different reasons. To interpret the report correctly, the type of lesion, echocardiographic measurements, effects on the heart chambers and the clinical situation must be considered together.

Heart valve diseases can narrow the opening of a valve, causing stenosis, or prevent complete closure, causing regurgitation. The criteria used to define severity are not the same for every valve or every type of lesion.

What mild, moderate and severe really mean

Mild generally indicates a limited hemodynamic abnormality. Many mild valve diseases do not cause symptoms and do not require specific treatment, but the practical significance depends on the valve involved, age and the rest of the cardiac picture.
Moderate identifies an intermediate lesion. It does not automatically mean “almost severe,” nor does it imply that progression is inevitable or rapid. Some forms remain stable for a long time, while others progress and require closer follow-up.

Severe means that the stenosis or regurgitation has reached criteria for a high degree of severity. This is a clinically important definition because it increases attention to symptoms, ventricular function, heart-chamber size and a possible indication for intervention.
However, “severe” does not automatically mean “intervention today.” For many valve diseases, the timing of a procedure depends on the combination of severity, symptoms, effects on the heart, procedural risk and the feasibility of valve repair or replacement.

How echocardiography determines the severity of valvular heart disease

Assessment is normally multiparametric: the cardiologist should not rely on a single isolated number. In stenosis, factors such as flow velocity, pressure gradients and valve area are considered; in regurgitation, jet characteristics, quantitative measurements and effects on the heart chambers are combined.
In aortic stenosis, for example, high-gradient disease is considered severe when the integrated picture typically includes a maximum velocity across the valve of at least 4.0 m/s, a mean gradient of at least 40 mmHg and a valve area no greater than about 1.0 cm². If these parameters do not agree, classification requires a more detailed analysis and should not be obtained by simply selecting the most concerning number.

In regurgitation, such as mitral regurgitation or aortic regurgitation, severity is defined by integrating several echocardiographic signs. Quantitative parameters such as regurgitant volume or effective regurgitant orifice can be very useful, but they have technical limitations and must be interpreted together with valve morphology, Doppler findings and heart-chamber dimensions.

What other information in the report matters besides severity

A good report does not describe only the valve. It is important to know whether the left or right ventricle has dilated, whether pumping function is preserved, whether the atria are enlarged and whether there are signs of increased pulmonary pressures.
This information helps show how long the valve disease has been affecting the heart and may contribute to treatment decisions. In some conditions, a change in ventricular size or function can become relevant even before the patient reports obvious symptoms.

The report may also contain terms that do not correspond to stenosis or regurgitation. Aortic valve sclerosis, for example, describes thickening and calcification of the valve without necessarily causing hemodynamically significant stenosis. Likewise, anatomical descriptions such as prolapse, annular calcification or bicuspid valve indicate structural features that must then be related to valve function.

How follow-up changes when valvular heart disease is mild, moderate or severe

In general, the greater the severity, the more important regular follow-up becomes. However, the exact frequency of follow-up cannot be determined from the word “mild,” “moderate” or “severe” alone: it depends on the valve involved, the type of lesion, the rate at which it has changed over time, cardiac function and the presence of symptoms.
This is why it is useful to compare the current report with previous ones. A progressive change in velocity, gradients, ventricular dimensions or degree of regurgitation may be more informative than a single examination read without context.

If new symptoms appear between follow-up visits, the already scheduled date should not automatically be awaited. Shortness of breath, reduced exercise capacity, chest pain, dizziness or fainting and new palpitations may justify earlier reassessment.

Frequently asked questions about the severity of valvular heart disease

What does mild valvular heart disease mean?
It means that the valve or blood-flow abnormality is mild according to the criteria used for that specific lesion. It often causes no symptoms and does not require immediate treatment.

Can moderate valvular heart disease become severe?
Yes. Some valve diseases can progress. The rate of progression varies greatly from person to person and from one valve disease to another.

Does severe valvular heart disease always require immediate intervention?
No. Severity is one of the decisive factors, but the timing of intervention also depends on symptoms, cardiac function and dimensions, the type of valve disease and the characteristics of the patient.

Why are there many numbers in the report in addition to the word severe or moderate?
Because echocardiography assesses severity using several parameters. A single value can be affected by flow conditions, blood pressure or measurement limitations and must be interpreted together with the other findings.

If the report says mild but I am very short of breath, what does that mean?
The symptom may have another cause or the situation may need reassessment. It is not correct to automatically attribute a major symptom to mild valve disease.