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The role of coronary perfusion changes in cardiac dysfunction associated with brain death
G Szabó1, C Sebening, T Hackert
1Department of Cardiac Surgery, University of Heidelberg, Germany.
Insights
Brain death impairs cardiac function by reducing coronary blood flow. Restoring coronary perfusion pressure can reverse this dysfunction, highlighting its critical role in organ donor hearts.
Area of Science:
- Cardiovascular Physiology
- Organ Transplantation
- Neurocritical Care
Background:
- Hemodynamic instability is common in organ donors, impacting cardiac transplantation outcomes.
- The relationship between altered loading conditions, coronary perfusion, and cardiac function post-brain death is not well understood.
Purpose of the Study:
- To investigate the role of coronary perfusion changes in cardiac dysfunction following brain death.
Main Methods:
- Utilized dogs on cardiopulmonary bypass for isolated left-ventricular (LV) contractions.
- Measured LV pressure, dP/dt, Emax, coronary blood flow (CBF), and myocardial oxygen consumption (MVO2).
- Induced brain death using a subdural balloon-catheter, maintaining coronary perfusion pressure at mean aortic pressure.
Main Results:
- Brain death initially caused a transient hyperdynamic state, increasing aortic pressure, LV pressure, dP/dt, Emax, CBF, and MVO2.
- Subsequently, aortic pressure and all measured cardiac parameters significantly decreased.
- Elevating coronary perfusion pressure to pre-brain death levels restored CBF and myocardial contractility.
Conclusions:
- Impaired coronary blood flow following brain death contributes to decreased cardiac contractility.
- Maintaining adequate coronary perfusion pressure is crucial for preserving cardiac function in potential organ donors.
Background:
Previous studies described a hemodynamic instability in the potential organ donor which has clinical relevance for cardiac transplantation. The possible pathophysiological link between altered loading conditions, coronary perfusion, and cardiac function after brain death has not been investigated yet. Therefore this study was undertaken to investigate the role of coronary perfusion changes during brain death in cardiac dysfunction.
Methods:
Dogs on cardiopulmonary bypass provided iso-volumetric left-ventricular (LV) contractions. By protocol, coronary perfusion pressure was kept at the level of mean aortic pressure. LV pressure, LV dP/dt, the slope of end-systolic pressure-volume relationship (Emax), coronary blood flow (CBF), and myocardial oxygen consumption (MVO2) were measured. Brain death was induced by a subdurally placed balloon-catheter.
Results:
Induction of brain death led to a transient hyperdynamic response with a significant increase of aortic and LV pressure, dP/dt, Emax, CBF, and MVO2. Thereafter, aortic pressure and, parallelly, LV pressure, dP/dt, Emax, CBF, and MVO2 decreased significantly. However, if coronary perfusion pressure was decoupled from aortic pressure and elevated to pre-brain death level, CBF and myocardial contractility were restored to baseline level.
Conclusion:
The impairment of coronary blood flow may contribute to decreased contractility after brain death.