A new method of assessing left ventricular function under assisted circulation using a conductance catheter.

Area of Science:

• Cardiovascular Physiology
• Medical Device Technology
• Surgical Research

Background:

• Assessing left ventricular (LV) systolic function typically requires interrupting assisted circulation (AC).
• Continuous monitoring of LV function is crucial during cardiopulmonary bypass (CPB) and left heart bypass (LHB).

Purpose of the Study:

• To investigate a novel method for evaluating LV systolic function during AC without cessation.
• To assess the utility of the preload recruitable stroke work (PRSW) index in canine models under CPB and LHB.

Main Methods:

• Utilized a LV volume catheter (conductance catheter) in canine models undergoing CPB and LHB.
• Subjected hearts to global or regional ischemia followed by reperfusion.
• Acquired instantaneous LV pressure-volume data during transient volume loading without interrupting bypass.
• Analyzed the relationship between stroke work (SW) and end-diastolic volume (EDV) to determine PRSW.

Main Results:

• A highly linear relationship was observed between SW and EDV (mean r = 0.956-0.987) across all study points.
• The PRSW, representing the slope of SW vs. EDV, significantly decreased after ischemia in both experimental groups.
• These findings demonstrate the sensitivity of PRSW to ischemic insults under AC conditions.

Conclusions:

• Measurement of PRSW during AC is a viable method for assessing LV systolic function.
• This technique allows for continuous evaluation of cardiac performance without the need to terminate bypass.
• The PRSW method shows promise for clinical application in patients requiring mechanical circulatory support.