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Effect of cardiopulmonary support on regional and global left ventricular function during transient coronary
C J Geannopoulos1, F S Leya, S A Johnson
1Loyola University Medical Center, Section of Cardiology, Maywood, IL 60153.
Insights
Extracorporeal cardiopulmonary support (CPS) unloads the left ventricle during temporary coronary artery blockage. However, this support does not prevent myocardial dysfunction caused by ischemia.
Area of Science:
- Cardiovascular Physiology
- Cardiac Surgery
- Mechanical Circulatory Support
Background:
- Myocardial ischemia during coronary occlusion can lead to significant left ventricular dysfunction.
- Extracorporeal cardiopulmonary support (CPS) is utilized in various cardiac conditions to support circulation.
- The specific effects of CPS on left ventricular unloading and ischemic dysfunction require further elucidation.
Purpose of the Study:
- To investigate the efficacy of extracorporeal cardiopulmonary support (CPS) in unloading the left ventricle.
- To assess the impact of CPS on mitigating ischemic dysfunction during transient coronary occlusion.
- To evaluate the influence of CPS on hemodynamic parameters and left ventricular function.
Main Methods:
- The study involved 10 anesthetized dogs subjected to serial circumflex coronary artery occlusions.
- Extracorporeal cardiopulmonary support (CPS) was initiated selectively during the second occlusion period.
- Hemodynamic parameters including blood pressure, heart rate, circumflex blood flow, LVEDP, and ventricular wall thickening were monitored.
Main Results:
- CPS significantly reduced preocclusion systolic blood pressure, double-product, and circumflex blood flow.
- Initiation of CPS led to a decrease in left ventricular end-diastolic pressure (LVEDP) and improved systolic thickening.
- Despite CPS-induced unloading, coronary occlusion still induced similar changes in LVEDP and wall thickening, irrespective of CPS presence.
Conclusions:
- Extracorporeal cardiopulmonary support effectively unloads the left ventricle during episodes of myocardial ischemia.
- CPS does not fully prevent the development of regional or global myocardial dysfunction induced by transient coronary occlusion.
- Further research is warranted to optimize CPS strategies for preserving myocardial function during ischemic events.
Abstract:
The ability of extracorporeal cardiopulmonary support (CPS) to unload the left ventricle and reduce ischemic dysfunction during transient coronary occlusion was studied in 10 anesthetized dogs. Three serial 60-second circumflex coronary artery occlusions were performed with CPS initiated only during the second occlusion. CPS significantly reduced preocclusion systolic blood pressure, blood pressure x heart rate double-product, circumflex blood flow, left ventricular end-diastolic pressure (LVEDP), peak negative dP/dt, and left ventricular systolic thickening. Circumflex occlusion caused changes in LVEDP and left ventricular wall thickening that were similar regardless of the presence or absence of CPS. These data suggest that CPS unloads the left ventricle during myocardial ischemia but does not prevent regional or global myocardial dysfunction.