Relationship between hemostatic markers and platelet indices in patients with aortic aneurysm.

The purpose of this study was to investigate whether platelet indices [platelet count, mean platelet volume (MPV), platelet-large cell ratio (P-LCR) and platelet distribution width (PDW)] could serve as diagnostic tools to evaluate the potential significance of platelet heterogeneity on thrombus formation in patients with aortic aneurysm (AA). Blood samples were obtained from 54 patients with AA (mean age 73 years; 40 males and 14 females), and from 120 age-matched controls (AC; mean age 74 years; 61 males and 59 females). Blood platelet indices were measured using an automated counter for all AC (n = 120) and AA (n = 54). Plasma thrombin-antithrombin III complex (TAT), alpha(2)-plasmin inhibitor-plasmin complex (PIC), D-dimer, von Willebrand factor antigen (vWF:Ag) and interleukin-6 (IL-6) were also measured in part of AC and AA. In AA patients, TAT, PIC, D-dimer, vWF:Ag and IL-6 levels were significantly (p < or =0.0005) higher than in AC. In the patients, TAT was significantly inversely correlated with platelet count (rho = -0.302, p = 0.038, n = 48), and significantly positively correlated with MPV (rho = 0.329, p = 0.0373, n = 48), P-LCR (rho = 0.361, p = 0.0134, n = 48) and PDW (rho = 0.315, p = 0.0466, n = 48). PIC was negatively correlated with platelet count and inversely correlated with MPV, P-LCR and PDW. vWF:Ag was not correlated with platelet count, and inversely correlated with MPV, P-LCR and PDW in the patients. IL-6 was positively correlated with platelet count, and significantly inversely correlated with MPV, P-LCR and PDW in the patients. In AC, vWF:Ag was inversely correlated with platelet count and significantly positively correlated with MPV, P-LCR and PDW. However, PIC, TAT and IL-6 were not correlated with platelet indices in AC. D-dimer was not at all correlated with platelet indices both in AA and AC. In conclusion, the correlation between platelet indices and plasma hemostatic factor levels, e.g. TAT, PIC, D-dimer, vWF:Ag and IL-6, will be important factors for the understanding of platelet heterogeneity in patients with AA.