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A new method of assessing left ventricular function under assisted circulation using a conductance catheter
R Matsuwaka1, H Matsuda, S Nakano
1First Department of Surgery, Osaka University Medical School, Japan.
Insights
This study introduces a new method to assess left ventricular (LV) systolic function during assisted circulation (AC). The preload recruitable stroke work (PRSW) measurement accurately reflects changes in LV function after ischemia without stopping bypass.
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.
Abstract:
A new method of assessing left ventricular (LV) systolic function without terminating assisted circulation (AC) was investigated using a LV volume catheter (conductance catheter) in canine cardiopulmonary bypass (CPB) (Group 1, n = 7) and left heart bypass (LHB) (Group 2, n = 5) models. The hearts were subjected to either 20 min of global ischemia (IS), with a subsequent 80 min of reperfusion under CPB, or regional IS under LHB. Instantaneous LV pressure-volume data acquisitions were repeated during transient (15 sec) acute volume loading without terminating bypass. The relationship between the stroke work (SW), determined as the area of the pressure-volume loop, and the end-diastolic volume (EDV), were highly linear at every study point (mean: r = 0.956-0.986 in Group 1, r = 0.974-0.987 in Group 2). The slopes of SW and EDV (preload recruitable stroke work: PRSW) significantly decreased after IS, in both Group 1 and Group 2. In conclusion, measurement of PRSW without terminating bypass seemed to be useful in evaluating LV systolic function in patients under AC.