Computed Tomography-Based Assessment of Transvalvular Pressure Gradient in Aortic Stenosis

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Radiology

Background:

• Computed tomography (CT) is crucial for cardiovascular anatomy assessment in aortic stenosis.
• CT is limited in determining hemodynamic parameters like transvalvular pressure gradient (TPG).

Purpose of the Study:

• To validate a reduced-order model for assessing TPG using CT data in aortic stenosis patients.
• To compare CT-derived TPG with invasive measurements.

Main Methods:

• Calculated TPG using a reduced-order model with patient-specific aortic flow rate (Q) and aortic valve area (AVA) from CT.
• Determined AVA via aortic valve leaflet segmentation and Q via left ventricular volumetric assessment.
• Validated against invasively measured TPG (TPG_catheter) in 84 aortic stenosis patients.

Main Results:

• CT-derived TPG (TPG_CT) and catheter-derived TPG (TPG_catheter) showed no significant difference (p=0.56).
• Bland-Altman analysis indicated good agreement (mean difference 2.6 mmHg, SD 19.3 mmHg).
• Strong correlation observed between TPG_CT and TPG_catheter (r=0.72, p<0.001).

Conclusions:

• A CT-based reduced-order model effectively assesses TPG in aortic stenosis.
• This method expands cardiac CT's utility for diagnosis and treatment planning.