Coronary microembolization causes long-term detrimental effects on regional left ventricular function

Abstract

Listen

Translate article

Objectives. To investigate whether coronary microemboli have long-term effects on left ventricular (LV) function in an experimental model. Furthermore, to determine if first-pass perfusion and late gadolinium enhancement (LGE) patterns differs between small- and large-sized microemboli. Design. Six pigs underwent left anterior descending (LAD)-coronary microembolization with small-sized (40–120 μm, n∼250 000) microemboli using a combined x-ray and MRI-system. MR-images before, one hour after and 7–8 weeks after microembolization were obtained. Results were compared to MRI obtained by large-sized (100–300 μm, n∼7200) microemboli. Results. Cine MRI showed an acute drop in ejection fraction (from 49.5 ± 2.6% to 32.5 ± 2.8) that substantially recovered at 7–8 weeks (47.5 ± 3.2%). Regional LV-function assessed as circumferential, longitudinal and radial strain declined in both microinfarcts and remote regions followed by partial recovery at 7–8 weeks. The decline in LV function and the severe perfusion deficit from the small microemboli was similar to the large microemboli at one hour. There was a significant recovery in perfusion at 7–8 weeks in the microinfarcts. LGE demonstrated the microinfarcts at 7–8 weeks but not at one hour and the microinfarcts were confirmed by histopathology. Conclusion. Microembolization causes long-term, regional LV dysfunction and this study confirmed the need of a comprehensive MRI-protocol for the detection of microinfarcts. These findings suggest that even small microemboli (40–120 μm in diameter), which may escape the distal protective devices influence cardiac function.