[Evaluation of a test for rapid detection of D-dimers for the exclusion of the diagnosis of venous thrombosis]. / Evaluation d'un test de détection rapide des D-dimères pour l'exclusion du diagnostic de thrombose veineuse.

OBJECTIVES: The SimpliRED whole blood D-dimer assay for exclusion of deep venous thrombosis in symptomatic outpatient appears to be a simple and rapid method; we wanted to confirm its reliability. METHODS: Fifty consecutive outpatients (mean age 57, range 20 to 89) referred to our department between September and December 1996, for clinically suspected deep venous thrombosis (DVT) were included. Hospitalized patients were excluded as well as patients under anticoagulant and pregnant women. DVT was diagnosed with our usual strategy of compression ultrasonography at the levels of the common femoral, the superficial femoral and the popliteal veins including the exploration of sural and saphenous veins. The D-dimer assay was performed, according to the manufacturer recommendation, blindly by a physician unaware of the results of ultrasonography within one hour. RESULTS: Eight of nineteen patients with DVT had a normal D-dimer test result Four had a sural DVT, but four had a proximal DVT. Furthermore four patients with normal D-dimers had superficial venous thrombosis. CONCLUSIONS: Our series does not confirm the high sensitivity and negative predictive value reported previously. To date it is premature to propose this assay as a first line test in the therapeutic management of patients with suspected DVT.

Native and gamma radiolysis-oxidized lipoprotein(a) increase the adhesiveness of rabbit aortic endothelium.

Accumulation of monocyte-derived foam cells in the arterial intima is a major event in the development of atherogenesis. We have examined whether native and oxidized lipoprotein(a) (Lp(a)) can induce adhesion of monocytic cells to aortic endothelium. The extensive oxidation of paired samples of Lp(a) and low-density lipoprotein (LDL) was achieved by O2.-/OH. free radicals produced by gamma radiolysis of water, leading to similar values for the formation of peroxidation markers (conjugated dienes, TBARS, 8-epi-PGF2alpha) for both Lp(a) and LDL. Rabbit aortic segments were incubated for 5 h in the presence of equimolar concentrations of native and oxidized preparations of Lp(a) and LDL (125 micromol cholesterol/l, corresponding to 40 and 30 mg protein/l for Lp(a) and LDL, respectively). The aortic segments were incubated with rhodamin-isothiocyanate labeled U937 monocytic cells for 30 min and cell adhesion was quantified by fluorescent microscopy. Native Lp(a), and to a larger extent oxidized Lp(a), significantly increased U937 cell adhesion by 2.3 and 2.7 fold compared to controls (P < 0.005 and P < 0.001, respectively). Monocytic cell adhesion was also increased by native LDL (1.6 fold, P < 0.005), and to a greater extent by oxidized LDL (2.3 fold, P < 0.001). Thus native Lp(a) enhances the adhesive properties of the arterial endothelium which may account for its proatherogenic action. Furthermore, our results show that oxidized Lp(a), as well as oxidized LDL, are potent stimuli of monocyte adhesion to endothelial cells.