A Pilot Study Comparing Aortic Valve Area Estimates Derived from Fick Cardiac Output with Estimates Based on...

Area of Science:

• Cardiology
• Medical Devices
• Hemodynamics

Background:

• Cardiac output (CO) estimation is crucial during cardiac catheterization, often using the modified Fick method (CO_Fick).
• Accurate aortic valve area (AVA) assessment is vital for managing severe aortic stenosis.

Purpose of the Study:

• To evaluate if Cheetah-NICOM monitor cardiac output (CO_Cheetah) can accurately estimate AVA in severe aortic stenosis patients when substituted into the Gorlin formula.
• To compare AVA derived from CO_Cheetah (AVA_Cheetah) against AVA derived from CO_Fick (AVA_Fick).

Main Methods:

• Prospective, non-randomized study at a single academic healthcare center.
• Concurrent measurement of CO_Fick and CO_Cheetah in 26 severe aortic stenosis patients.
• Bland and Altman analysis to assess bias and limits of agreement between AVA_Cheetah (spot and averaged) and AVA_Fick.

Main Results:

• The mean difference (bias) between averaged AVA_Cheetah and AVA_Fick was 0.11 cm² (95% LOA ±0.42 cm²).
• The bias for spot AVA_Cheetah was 0.14 cm² (95% LOA ±0.42 cm²).
• No proportional bias was detected, but limits of agreement were too wide for interchangeability.

Conclusions:

• AVA_Cheetah provides a reasonably accurate estimate of AVA compared to AVA_Fick in severe aortic stenosis.
• The Cheetah-NICOM monitor shows potential but is not yet interchangeable with the modified Fick method for AVA calculation in this context.