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Updated: Jul 6, 2026
Myocardial Infarction and Functional Outcome Assessment in Pigs
Published on: April 25, 2014
Left ventricular performance and coronary flow after coronary embolization with plastic microspheres
Insights
Embolizing canine hearts with microspheres reduced coronary flow and ventricular performance. This study highlights risks of embolization during cardiopulmonary bypass, impacting coronary flow and cardiac function.
Area of Science:
- Cardiovascular Physiology
- Cardiac Surgery
- Biomedical Engineering
Background:
- Cardiopulmonary bypass systems can lead to embolization.
- Emboli may compromise coronary flow and ventricular performance.
- Understanding these effects is crucial for patient outcomes.
Purpose of the Study:
- To investigate the impact of microsphere embolization on coronary flow.
- To assess the effects on left ventricular performance and compliance.
- To relate findings to clinical scenarios involving pump oxygenator systems.
Main Methods:
- Isolated canine hearts were perfused with arterial blood.
- Coronary beds were progressively embolized with large (865 μm) or small (10 μm) microspheres.
- Coronary flow, left ventricular pressure, and circumference were monitored.
Main Results:
- Large microspheres progressively reduced coronary flow and ventricular performance.
- Small microspheres initially increased coronary flow, suggesting vasodilator release.
- Both emboli types decreased ventricular compliance and ultimately impaired performance.
Conclusions:
- Microsphere embolization significantly impairs coronary flow and cardiac function.
- Findings are relevant to embolization risks during cardiopulmonary bypass.
- Reduced ventricular compliance and performance are key consequences.
Abstract:
Coronary flow, left ventricular circumference, and left ventricular pressure were observed in the isovolumically contracting, isolated canine heart supported with arterial blood from a donor. Systolic pressure, heart rate, and coronary perfusion pressure were held constant while the coronary bed was progressively embolized with either large (average 865 mu) or small (average 10 mu) polystyrene microspheres. During embolization with large microspheres, coronary flow diminished progressively. After sufficient embolization, decreased ventricular performance was indicated by a rise in end-diastolic pressure. During embolization with small microspheres, coronary flow initially increased, which suggests the effective release of a vasodilator substance. Return of coronary flow to control levels occurred only after the end-diastolic pressure rose, on the average, to above 30 mm Hg. After embolization with both sizes of microspheres, ventricular diastolic pressure-volume relationships showed decreased ventricular compliance. This was attributed, in part, to edema of the ventricular wall and, in part, to focal shortening of the sarcomeres where the circulation was compromised. Embolization with both sizes of microspheres ultimately caused a decrease in ventricular performance, although when the systolic pressure was increased the usual relationship between peak developed wall stress, and end-diastolic pressure showed less of a descending limb than that found in the nonembolized, isolated heart. It is felt that the data summarized above have bearing on ventricular performance and coronary flow in clinical situations where hearts are perfused through pump oxygenator systems and are thereby subject to embolization from aggregated clumps of platelets and fibrin.
