The incidence of emboli during cardiac surgery: a histopathologic analysis of 2297 patients.

OBJECTIVE: Manipulation of the atherosclerotic aorta during cardiac surgery is assumed to cause embolization, which can contribute to adverse outcomes. Recently, as a result of worldwide trials deploying the Embol-X intraaortic filter during cardiac surgery, such emboli were captured and processed for histopathologic analysis. METHODS: Filters with a pore size of 120 microns were placed in 2297 patients who underwent the following operations: coronary artery bypass grafting (CABG) (70%), valve (17%), combination CABG/valve (11%), and other (2%). RESULTS: The filters captured at least one embolus in 98% of the patients. An average of 8.3 particles was captured per filter (range of 0-74). The surface area of the emboli was on an average 5.8 mm2 (range of 0-188 mm2). Histologic analysis of the captured particles indicated that in 79% of the filters fibrous atheromata were noted, in 44% there were platelets and fibrin, 8% had red blood cell thrombus, 3% had fibro-fatty/adventitial tissue, 2% had other material including cartilage, myocardium, lung, suture, and a teflon pledget. Of the patients enrolled, 1569 were high-risk. The average number of particles captured in the high-risk patients was 8.5 versus 5.8 for the low- to moderate-risk patients (P < .0001). Concomitantly,there was an increase in the embolic burden between the higher- and lower-risk patients (surface area 6.6 vs. 4.0 mm2, P < .0001). CONCLUSION: These data show the ubiquitous incidence of emboli during cardiac procedures. Intraaortic filtration should reduce adverse outcomes as was demonstrated for the high-risk patients in this study. Aortic manipulation during cardiac surgery can cause embolization and increase morbidity. The use of an intraaortic filter can decrease the embolic burden. We now report the histopathologic analysis of these emboli.