Comparison between Cardiac Output and Pulmonary Vascular Pressure Measured by Indirect Fick and Thermodilution...

Area of Science:

• Cardiology
• Pulmonary Hypertension Diagnostics
• Hemodynamics

Background:

• Right heart catheterization (RHC) is crucial for diagnosing pulmonary hypertension (PH) and assessing its treatability.
• Estimating cardiac output (CO) and calculating pulmonary vascular resistance (PVR) are key components of RHC.
• Discrepancies exist between the indirect Fick and thermodilution methods for CO and PVR measurements, necessitating further investigation.

Purpose of the Study:

• To evaluate the agreement between CO and PVR values obtained using the thermodilution and indirect Fick methods during RHC.

Main Methods:

• Retrospective analysis of 55 patients undergoing RHC with both CO measurement methods.
• Collected RHC measurements and clinical data.
• Compared CO and PVR values derived from thermodilution and indirect Fick methods for each patient.

Main Results:

• Mean CO: Thermodilution 4.94 L/min vs. Fick 5.82 L/min.
• Mean PVR: Thermodilution 3.33 WU vs. Fick 2.71 WU.
• Significant correlation (R²=0.78, p=0.004) between PVR methods in normal mPAP patients; no significant correlation in elevated mPAP patients.

Conclusions:

• The indirect Fick and thermodilution methods can lead to different classifications of PVR, potentially misclassifying patients with elevated mPAP.
• Recommend performing both methods in RHC, prioritizing thermodilution values when discrepancies arise, especially in patients with mPAP > 25 mmHg.