What is a normal transaortic gradient pressure?

From the Guidelines

A normal transaortic gradient pressure is typically considered to be below 10 mmHg in healthy adults. This represents the pressure difference between the left ventricle and the aorta during systole when blood flows across the aortic valve. The gradient is measured using Doppler echocardiography during cardiac evaluation and is an important parameter for assessing aortic valve function. In clinical practice, gradients between 10-20 mmHg may indicate mild stenosis, while moderate aortic stenosis is typically associated with gradients of 20-40 mmHg, and severe stenosis with gradients exceeding 40 mmHg 1.

Key Considerations

• The transaortic gradient pressure is a critical measure for assessing the severity of aortic stenosis, with higher gradients indicating greater obstruction.
• A mean transaortic valve gradient ≥20 mmHg carries a greater than 50% 5-year mortality independent of age, gender, systolic and diastolic dysfunction 1.
• Severe stenosis is suggested by an AS jet velocity >4 m/s or a mean gradient >30–40 mmHg provided that valve area does not exceed 1.0 cm2 at any flow rate 1.

Clinical Implications

• In patients with severe, symptomatic, and calcific AS, the only effective treatment is surgical or transcatheter AVR, resulting in improved survival rates, reduced symptoms, and improved exercise capacity 1.
• The prevalence of a LV ejection fraction (LVEF) <50% in patients at greater than intermediate risk for aortic valve replacement is estimated between 30–50% 1.
• Treatment of hypertension is a valid target in patients with AS, with pragmatic goals being a systolic blood pressure of 130–139 mmHg and a diastolic blood pressure of 70–90 mmHg 1.

Recommendations

• A normal transaortic gradient pressure should be considered as a key factor in the assessment of aortic valve function, with gradients below 10 mmHg generally considered normal.
• Patients with symptoms, impaired LV systolic function, or other cardiac surgery indications should undergo valve replacement, as determined by the severity of AS and symptomatic status 1.

From the Research

Normal Transaortic Gradient Pressure

• The normal transaortic gradient pressure is not explicitly defined in the provided studies, but we can look at the gradient values mentioned in the context of different conditions:
  • In patients with severe aortic stenosis and left ventricular dysfunction, a high transaortic pressure gradient is considered to be greater than or equal to 35 mmHg 2.
  • A study on Direct Flow aortic valve implantation reported a significant transaortic gradient after the procedure, with peak/mean gradients of 80/45 mmHg 3.
  • In patients with classical low-flow, low-gradient aortic stenosis, a mean transaortic gradient of less than 40 mmHg is considered low 4.
  • Another study found that elevated aortic valve gradients after transcatheter aortic valve implantation were common, but their clinical impact was uncertain, with a mean gradient of 20 mmHg used as a cutoff in the analysis 5.
• It appears that the definition of a normal transaortic gradient pressure may vary depending on the context and the specific condition being studied.
• In general, a mean transaortic gradient of less than 20-30 mmHg may be considered relatively normal, while higher gradients may indicate significant aortic stenosis or other valve-related issues 2, 4, 5.