A novel speckle-tracking echocardiography parameter assessing left ventricular afterload

Area of Science:

• Cardiology
• Critical Care Medicine
• Echocardiography

Background:

• Left ventricular stroke work index (LVSWI) and afterload-related cardiac performance (ACP) are crucial for assessing septic cardiomyopathy but require invasive measurements.
• Non-invasive methods are needed to evaluate left ventricular (LV) afterload and cardiac performance in clinical settings.

Purpose of the Study:

• To evaluate the non-invasive Pressure-Strain Product (PSP) using speckle-tracking echocardiography.
• To determine if PSP can predict invasive LVSWI, ACP, and serum lactate in an ovine model of septic cardiomyopathy.
• To assess PSP's ability to differentiate acute respiratory distress syndrome (ARDS) sub-phenotypes with or without sepsis.

Main Methods:

• Sixteen sheep with ARDS were studied, divided into sepsis-like and non-sepsis-like groups.
• Invasive hemodynamic parameters (LVSWI, ACP) and serum lactate were measured alongside transthoracic echocardiography.
• Two PSP indices (PSPcirc, PSPrad) were calculated by multiplying mean arterial blood pressure with global circumferential or radial strain.

Main Results:

• PSPcirc strongly correlated with LVSWI (r²=.66) and ACP (r²=.82) in the sepsis-like group.
• PSPcirc accurately predicted LVSWI (AUC .86) and ACP (AUC .88).
• PSPrad showed predictive value for serum lactate (AUC .75).

Conclusions:

• The novel Pressure-Strain Product (PSP) shows potential for non-invasively assessing cardiac function in septic cardiomyopathy.
• PSP may serve as a valuable tool for predicting LVSWI and ACP, and is associated with serum lactate levels.