Transaortic Flow Rate and Risk Stratification in Moderate Aortic Stenosis

Area of Science:

• Cardiology
• Echocardiography
• Valvular Heart Disease

Background:

• Stroke volume (SV) is commonly used for flow status in aortic stenosis (AS).
• Flow rate (FR) offers a more precise blood flow descriptor.
• Prognostic significance of transaortic FR in moderate AS is understudied.

Purpose of the Study:

• To evaluate the association between transaortic FR and clinical outcomes in patients with moderate AS.
• To identify predictors of impaired transaortic FR in this population.

Main Methods:

• 292 outpatients with moderate AS (aortic valve area 1-1.5 cm²).
• Transaortic FR calculated via derivation (FRder) and validated with direct calculation (FRdir).
• Primary endpoint: all-cause mortality or heart failure hospitalization.

Main Results:

• Lower FRder (<218 mL/sec) independently predicted adverse outcomes (aHR 2.17).
• FRder showed excellent correlation with FRdir (R²=0.93).
• Independent predictors of low FRder included female sex, renal insufficiency, prior MI, low SV index, and tricuspid regurgitation.

Conclusions:

• Transaortic FRder <218 mL/sec is an independent predictor of adverse events in moderate AS.
• Further research is needed to guide management for patients with impaired FR.
• Potential benefits of intensive monitoring or earlier intervention require investigation.