From the Guidelines
Severe aortic stenosis is defined by a valve area less than 1.0 cm², with a mean aortic valve gradient ≥ 40 mm Hg, or peak aortic valve velocity Vmax ≥ 4.0 m/s, as stated in the most recent guidelines 1.
Valve Area Guidelines
The valve area is a critical parameter in diagnosing and managing severe aortic stenosis.
- A valve area of less than 1.0 cm² is generally considered indicative of severe aortic stenosis.
- Additional factors such as symptoms, left ventricular function, and other hemodynamic parameters are also important in determining the severity of aortic stenosis and the need for intervention.
Diagnosis and Management
The diagnosis of severe aortic stenosis typically involves echocardiography, which remains the gold standard for assessing valve area and other hemodynamic parameters 1.
- Low-dose dobutamine stress echocardiography may be used to differentiate between pseudo-severe and true severe aortic stenosis, especially in patients with low-flow, low-gradient aortic stenosis 1.
- Intervention, such as surgical valve replacement or transcatheter aortic valve implantation, is typically considered when patients develop symptoms or show signs of left ventricular dysfunction.
Recent Guidelines
The most recent guidelines from 2024 emphasize the importance of valve area, mean gradient, and peak velocity in defining severe aortic stenosis 1.
- These guidelines also highlight the role of shared decision-making with patients and families, especially in high-risk or challenging settings.
- The management of patients with severe aortic stenosis requiring noncardiac surgery involves careful consideration of the timing and type of intervention, as well as close monitoring to avoid complications.
From the Research
Valve Area Guidelines for Severe Aortic Stenosis
The valve area guidelines for severe aortic stenosis are based on several studies that have investigated the outcomes of patients with different valve areas.
- A valve area of ≤0.75 cm2 is considered severe aortic stenosis, with an aortic jet velocity of ≥4.5 m per second or a mean transaortic gradient of ≥50 mm Hg 2.
- A valve area of <1.0 cm2 is also considered severe aortic stenosis, and is associated with increased mortality and heart failure 3.
- The current guidelines define severe aortic stenosis as an aortic valve area (AVA) ≤1.0 cm2, but some authors have suggested that the AVA cut-off be decreased to 0.8 cm2 4.
- Patients with an AVA of 0.8-0.99 cm2 have variable outcomes, and are more precisely defined by flow-gradient status 4.
Clinical Features and Prognosis
The clinical features and prognosis of patients with isolated severe aortic stenosis and valve area less than 1.0 cm2 are:
- Patients with an AVA of 0.8-0.99 cm2 comprise predominantly normal-flow, low-gradient (NFLG) AS 4.
- The frequency of symptoms is not significantly different between an AVA of 0.8-0.99 cm2 and 1.0-1.3 cm2 4.
- The combined endpoint of death from any cause or aortic valve replacement at or before 3 years is achieved in 71%, 52%, and 21% of patients with an AVA of <0.8 cm2, 0.8-0.99 cm2, and 1.0-1.3 cm2, respectively 4.
Management Approaches
The management approaches for patients with severe aortic stenosis include:
- Balloon aortic valvuloplasty as a bridge to aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI) in patients with severe symptomatic aortic stenosis 5.
- Early surgery or conservative care for asymptomatic aortic stenosis, with early surgery being associated with improved outcomes 2.
- Aortic valve replacement, which reduces mortality and heart failure in patients with an AVA <1.0 cm2 3.