Objective: Intra-aortic filtration during coronary artery bypass grafting (CABG) has the potential to harvest all particles embolized into the aorta proximal to the filter. The aim of this study was to determine risk factors for embolization of particles during CABG.
Methods: Forty consecutive patients undergoing conventional multi-vessel CABG were included in the study. Plaques of the ascending aorta were determined by epiaortic ultrasonography prior to aortic manipulation. Intra-aortic filters (Embol-X, Mountain View, CA) were inserted before removal of the aortic cross-clamp and extracted after end of cardiopulmonary bypass. Filters underwent histologic analysis at a core lab (Stanford University, Stanford, CA).
Results: The average number of proximal anastomoses was 2.2 (SD 0.55, range 1-3). All patients had particles in the filters. The average number of particles per filter was 10.5 (SD 5.4, range 2-23) with a mean surface area of 8.1mm(2) (SD 9.3, range 0.3-51.1). Fibrous atheroma was extracted from 85% (34/40) of the filters. Logistic regression explained 46% (r(2)=0.46, P<0.001) of the number of particles harvested by the filters. The most important independent risk factors for particles were number/grade of atheromas in the ascending aorta (P<0.01), obesity (P<0.02), hypertension (P<0.02) and number of proximal anastomoses (P<0.02).
Conclusions: Atheroma in the ascending aorta is the most important risk factor for particle embolization during CABG. The number of particles correlated with the extent of atheromatous disease in the ascending aorta and logistic regression identified hypertension, obesity and the number of proximal anastomoses to have significant influence on the number of captured particulates.