Diagnostic value of a new sensitive membrane based technique for instantaneous D-dimer evaluation in patients with clinically suspected deep venous thrombosis.

BACKGROUND: Plasma D-Dimer analysis, using ELISA assays, has demonstrated in previous studies a high sensitivity, suggesting its utility in excluding deep venous thrombosis (DVT). AIM: To assess the performance of a new rapid plasma D-Dimer ELISA measurement in suspected DVT patients with recent clinical signs, not exceeding one week. METHODS: A prospective study of patients admitted for a suspected recent DVT. Contrast venography or compression ultrasonography were performed within 24 h of admission. A new membrane based ELISA technique, which uses an immunofiltration and two complementary monoclonal antibodies was tested. Results were expressed as positive or negative. A standard plasma D-Dimer ELISA measurement was also performed. D-Dimer performances were assessed at the end of the study. RESULTS: 265/448 patients had a proven DVT (72 distal, 193 proximal). The sensitivity of the instantaneous method in the diagnosis of overall DVT is 92 +/- 3.4% (95% CI), and specificity is 36.6 +/- 6.9%. Positive predictive value is 67.7 +/- 4.8% and negative predictive value is 76.1 +/- 8.9%. Sensitivity and negative predictive values reach 97.9 and 94.3% in the diagnosis of proximal DVT, but only 76.3 and 79.7% in the diagnosis of distal DVT. Similar results are observed with the standard ELISA method. CONCLUSION: This new rapid plasma D-Dimer measurement appears highly sensitive, and could substitute the older ELISA methods. Both methods provide lower sensitivity in the case of a distal DVT location.

Factor V Leiden prevalence in venous thromboembolism patients.

BACKGROUND: Recent findings have demonstrated a high frequency of activated protein C resistance in patients suffering from deep venous thrombosis (DVT). This abnormality has been related to a mutation in the factor V gene (at nucleotide position 1,691, guanine to adenine [G-->A] substitution). AIM: To assess the frequency of the mutation in unselected inpatients with a proved DVT. To study the clinical characteristics of such patients. METHODS: All consecutive patients admitted to the hospital because of a clinical suspicion of DVT were eligible. Diagnosis of DVT with the help of venous ultrasound imaging or venography. Ventilation and perfusion lung scan was performed in all patients, and interpreted according to the Prospective Investigation of Pulmonary Embolism Diagnosis criteria; in patients with a low- or intermediate-probability lung scan, pulmonary angiography was requested. Polymerase chain reaction amplification was performed in patients with a proved DVT. A control group consisted of bone marrow volunteer donors. RESULTS: From July 1994 to November 1995, 165 patients were included. Thrombosis was considered as distal in 77 and proximal in 88; an associated pulmonary embolism (PE) was found in 75 patients. Of 165 patients, 24 (14.5%) showed the factor V gene mutation (95% confidence interval, 9.4 to 19.8); the mutation was present in 3.5% of 200 bone marrow volunteer donors; odds ratio for having DVT in the presence of the mutation was 4.1. No difference in the level of DVT, or the presence of an associated PE was observed according to the presence of the mutation. Patients with the mutation have a significantly more frequent history of DVT (p=0.04) and more previous reported episodes (1.1 vs 0.6; p=0.04). CONCLUSION: The factor V mutation is frequent in unselected DVT patients. No difference in the severity of the thrombosis episode was observed in these patients.

Decreased in vitro megakaryocyte colony formation in chronic idiopathic thrombocytopenic purpura.

In vitro megakaryocyte colony formation was studied in 25 patients with chronic idiopathic thrombocytopenic purpura (ITP), and compared to 16 controls. A significantly lower number of megakaryocyte progenitors (CFU-MK) was observed in patients (10.8 +/- 12.0 CFU-MK per 10(5) bone-marrow non-adherent mononuclear cells (NAMC), compared to controls (22.5 +/- 15.4 CFU-MK); P < 0.002. Only six patients had a normal number of CFU-MK. The number of CFU-MK was not correlated to initial platelet count (P = 0.35). These findings indicate that in vitro CFU-MK could be of interest in the diagnosis of chronic ITP, and also could be predictive for chronicity in patients with acute ITP.

Association between IgM anticardiolipin antibodies and deep venous thrombosis in patients without systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) are at risk of developing deep venous thrombosis (DVT). Should anticardiolipin antibodies (aCL) be detectable, this risk is significantly raised, particularly when these autoanti-bodies are cofactor-dependent. We conducted a cross-sectional study of consecutive unselected outpatients referred for clinical suspicion of DVT, as an attempt to address the following questions: firstly, were aCL antibodies associated with DVT in non-SLE patients? Secondly, was this association related to the cofactor dependence? From March 1992 to February 1994, 208 patients were enrolled in the study. Venography was positive in 110 patients (DVT patients), while the diagnosis of DVT could not be confirmed in the remaining 98 (referred to as disease controls). ACL was measured by ELISA, for IgG and IgM isotypes in two ways: fetal calf serum or bovine serum albumin were used as blocking agents to distinguish between cofactor-dependent and cofactor-independent antibodies. Positive aCL was defined as optical density (OD) values greater than the 95th percentile of OD distribution of 60 healthy controls. We found a high frequency of positive IgG aCL antibodies in both DVT patients and in disease controls (25.5 vs 23.5%). We suggest an association between IgM aCL and DVT. This association was, however, not dependent on the cofactor requirement.

Severe arterial thrombosis in a congenitally factor VII deficient patient.

We report a patient with congenital factor VII deficiency who developed severe arterial thrombosis. A 63-year-old-woman presented low factor VII clotting activity, amidolytic activity and antigen level < 4%. Activated factor VII plasmatic level was < 0.03 ng/ml compared to 4 ng/ml for the control value. She developed severe aorto-iliac thrombosis. 7 d before the thrombotic event, factor VII replacement therapy had been infused. Successful low molecular weight heparin therapy led to total disappearance of the aorto-iliac thrombus without bleeding complications. This suggests that factor VII infusion might have a thrombogenic effect in vivo and might be responsible for thrombosis.