Re-Exploration of Flow Rate in Low-Flow, Low-Gradient Aortic Stenosis.

Area of Science:

• Cardiology
• Echocardiography
• Hemodynamics

Background:

• Transaortic flow rate (TFR) is an emerging hemodynamic index in aortic stenosis (AS).
• This study focuses on patients with low-flow, low-gradient (LF-LG) AS and reduced left ventricular ejection fraction (LVEF < 50%).

Purpose of the Study:

• To assess hemodynamic determinants of TFR at rest and during dobutamine stress.
• To evaluate the prognostic significance of TFR for 3-year survival in LF-LG AS patients.

Main Methods:

• Dobutamine stress echocardiography (DSE) was performed on 86 patients.
• Patients were classified into true severe, pseudo-severe, and indeterminate AS groups.
• TFR and associated parameters were assessed at rest and peak stress; 3-year survival was evaluated.

Main Results:

• Peak stress TFR differed significantly between AS groups (p < 0.01), unlike rest TFR.
• Stress TFR was a significant independent predictor of 3-year survival (p = 0.03), with an optimal threshold of >195 mL/s.
• Rest TFR was associated with cardiac output, arterial compliance, and valvulo-arterial impedance; stress TFR was predominantly linked to cardiac output.

Conclusions:

• Stress TFR reflects left ventricular contractile reserve and holds prognostic value in LF-LG AS.
• Stress-based TFR assessment improves diagnostic accuracy and clinical decision-making in ambiguous AS cases.