Erythrocyte aggregation as a cause of slow flow in patients of acute coronary syndromes

Background: There are multiple lines of evidence to suggest the role of erythrocyte aggregation (EA) in microcirculatory dysfunction during conditions of very slow flow. Such conditions might develop in the myocardium of patients with acute coronary syndromes (ACS). Methods: EA as a function of shear stress was evaluated by using a cell flow properties analyzer (CFA) in a cohort of 91 ACS patients and in 36 patients with non specific chest pain or heart failure at the time of cardiac catheterization. Results: The ACS group included 34 patients with acute myocardial infarction and 57 patients with unstable angina. In addition, we examined 36 patients who underwent angiography for non specific chest pain or heart failure. A significant (r=0.44, p<0.0005) correlation was found between the concentration of fibrinogen and the average aggregate size (AAS) only when using conditions of very slow flow and applying relatively low (0.15 dyn/cm(2)) shear stress in the ACS group. This correlation decreased and became insignificant when applying shear stress forces of 1 dyn/cm(2) and more. This correlation was nonsignificant for all the 5 shear stress forces (between 0.15 and 4 dyn/cm(2)) in the samples obtained from the non-ACS group. Conclusion: Erythrocytes that are suspended in autologous plasma obtained from patients with ACS tend to aggregate in conditions of very slow flow. These findings might be detrimental in terms of microcirculatory flow in ACS patients and might open new therapeutic options such as the use of low dose thrombolysis following PCI. (C) 2011 Elsevier Ireland Ltd. All rights reserved.