Size distribution of embolic material produced at aortic cross-clamp manipulation

Abstract

Objectives. The association between aortic atherosclerosis and neurological damage during cardiac surgery is well recognized. The purpose was here to analyze the size distribution of particles produced at cross-clamp manipulation of the ascending aorta. Design. A human cadaveric aortic perfusion model of retrograde design was applied (n=27). With this model, washout samples were collected from the pressurized ascending aorta during cross clamp manipulation. Before the experiment, the aorta was flushed to remove debris and with a baseline sample collected. The cross-clamp was opened to collect ten repeated aliquots with dislodged particles. Collected washout samples were evaluated by digital image analysis and microscopy. Results. Cross-clamping produced a significant output of particles, which was seen for size intervals of 1 mm and smaller (p=0.002 to p=0.022). In all size intervals the particle output correlated with the degree of overall aortic calcification (p=0.002 to p=0.025). The model generated substantially more small-size particles than large debris (p<0.010). Conclusions. Aortic clamping was here verified to dislodge aortic debris which correlated with the degree of observed calcification. Macroscopic particles were few. In contrast, cross-clamping produced substantial numbers of small-size particles. These findings emphasize microembolic risks associated with cross-clamping of atherosclerotic vessels.

Key words::

• Cardiac surgery
• aorta
• atherosclerosis
• surgical clamp
• embolism
• stroke

Acknowledgements

The authors would like to acknowledge Mrs Anne-Marie Österdahl, Mr Dan Nylund, Dr Eva Lundin and Dr Karin Sixtensdotter Graffmo at the Department of Clinical Pathology, Umeå University Hospital. This work was supported by Swedish Society for Medical Research, funds of the Medical Faculty, Umeå University Hospital, the Heart Foundation of Northern Sweden, and the Swedish Stroke Foundation.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.