Cannulation of the noncalcified aorta generates particles of microembolic nature:: An experimental study using pig aorta

Background and aim of the study. Aortic cannulation during cardiac surgery is a potential etiological factor for perioperative stroke. Cannulae may dislodge aortic-wall calcifications. In addition, the sharp edge of the cannula-tip may shear, off vessel-wall tissue, which can be expelled into the lumen. This hypothesis concerning source of emboli was tested in a noncalcified aortic perfusion model. Methods: Pig aortas were pressurized and cannulated. Washout samples were collected before and after cannulation (n = 40). Particles were deposited onto a 10-mu m filter and evaluated by microscopy and digital image analysis. Results: A higher incidence of particles generated by cannulation was noted as compared to before the maneuver (p < 0.001). This increase included small (<0.1 mm, p < 0.001) and intermediate-size particles (0.1-0.5 mm, p < 0.001). Particles above 0.5 mm were few and were not associated with cannulation. Conclusions: Cannulation was a source of embolic material in the noncalcified aortic model. However, these particles were less than 0.5 mm in diameter and may contribute to neurocognitive decline after cardiac surgery.