Classification – Part I
The clinical classification of aortic stenosis is one of the most detailed and it was recommended in 2014 in the publication of the American valve disease guideline. All valvulopathies were classified in stages from A to D according to the severity of the lesion and the presence of symptoms.
Patients in stage A of aortic stenosis are patients with valve sclerosis without a major gradient or those with bivalvular aortic valve also with no major gradient.
Stage B is characterized by the presence of a stenotic type lesion, but with a mean gradient less than 40 mmHg and a valve area above 1 cm2. They are patients with mild to moderate injury, therefore, do not have hemodynamic repercussions to present symptoms due to valve disease alone.
From the moment that the lesion becomes important, that is, a mean gradient above 40 mmHg and a valve area below 1 cm2, we observe the presence of symptoms. In the case of asymptomatic patients, we define it as stage C. In the presence of symptoms, the patient is classified as stage D.
In stage C, we further subdivide, according to the presence of systolic dysfunction of the left and/or ventricular cavitary dilation. Patients with a drop in ejection fraction (<50%) are classified as C2. Those who remain with the ejection fraction within normal limits are considered C1. As it is a pressure overload, it is rare to see dilations in the absence of systolic dysfunction.
Within stage D, there are even more subclassifications. It is expected that the patient will present a mean gradient above 40 mmHg and a valve area below 1 cm2, regardless of the ejection fraction. This is stage D1 (classic D1 – preserved LVEF, D1 afterload mismatch – reduced LVEF). When the gradient does not follow the severity of the valve area, we can be faced with low gradient aortic stenosis and then stages D2 and D3 appear.
Stage D2 is called the classic low-flow low-gradient, in which we found a patient with a valve area below 1 cm2, a mean gradient below 40 mmHg and the presence of left ventricular systolic dysfunction (<50%). At this point, it is worth opening a parallel discussion on the proper propaedeutics of these cases.
1 – Otto CM, Bonow RO. A Valvular Heart Disease – A companion to Braunwald’s Heart Disease. Fourth Edition, 2014.