ALBERT

Description: The diagnosis of deep venous thrombosis (DVT) is mostly dependent upon duplex ultrasound (DUS) examination of the affected extremity. Data from our laboratory implicates P-Selectin and microparticles (MPs) in the pathogenesis of venous thrombosis. A prospective study was performed to determine the sensitivity and specificity of plasma assays for D-Dimer, soluble P-selectin (P-selectin), and total MPs in patients with documented DVT by DUS. Three groups of individuals were examined: Group 1, 30 normal volunteers; Group 2, 22 patients positive for DVT on DUS (DVT); and Group 3, 21 patients with symptoms of leg pain but negative DUS for DVT (SMP). D-Dimer was measured by the Advanced D-Dimer assay (Dade-Behring, Deerfield, IL), P-Selectin was measured by ELISA (R&D, Minneapolis, MN.) and MPs were assayed by flow cytometry. Total MPs are cell fragments detected by anti-CD41 and anti-CD11b that are 〈 1 micron, as seen on flow cytometry. Group 1 individuals have D-Dimer levels of 1.53±0.12 mg/dl, P-Selectin of 0.34±0.05 ng/mg total protein (TP), and total MP of 370,103±41,910 particles/200 microliters of platelet-poor plasma. No differences in age (mean=48 vs. 51 yrs, respectively), weight, BMI, use of OCP/HRT, smoking, family history of DVT, or trauma history were noted between DVT and SMP patients. Patients with DVT were more likely to have traveled recently or have a malignancy present. 100% of DVT patients were at highest risk (score≥5) for thrombosis by thrombosis risk assessment (Caprini, JA, J. Thromb. Thrombolysis, 9:253, 2000) while only 62% of SMP patients were at highest risk. Group 2 individuals (DVT) have D-Dimer values of 8.20±2.03 mg/dl, P-Selectin of 0.98±0.11 ng/mg TP, and MPs 129±17% of control. Group 3 individuals (SMP) have D-Dimer values of 3.12±0.79 mg/dl, P-Selectin of 0.55±0.08 ng/mg TP, and MPs 99±12% of control. Differences were statistically significant between groups 2 and 3 for D-Dimer (p=0.01) and P-selectin (p