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Recently, the sensitivity of impedance plethysmography (IPG) for the diagnosis of acute deep-vein thrombosis (DVT) in symptomatic outpatients has been questioned. In order to verify whether a change in the venographic pattern of DVT has occurred over years, accounting for the decreased sensitivity of IPG, the authors compared two series of consecutive venograms demonstrating proximal DVT, performed between 1984–1988 (166 patients) and 1990–1992 (140 patients). They evaluated both the extension and the occlusiveness of deep-vein thrombi in the two series. Moreover, changes in the referral characteristics of patients were investigated. In the second series of venograms a significant decrease in thrombi extension, expressed by a lower prevalence of iliac vein thrombosis (29% versus 43%; P = 0.0074) was observed; moreover, a significant increase in the prevalence of nonocclusive thrombi (22% versus 8%; P = 0.0004) was also recorded in the second series when compared with the first. During the study period, among the referral characteristics of patients, the authors observed both a significant decrease in the prevalence of proximal DVT (from 31% to 24%; P < 0.01) and a slight and not statistically significant decrease in the median time elapsed between onset of symptoms and referral for objective testing (from eight and a half to seven days). In conclusion, proximal deep-vein thrombi are currently less extensive and occlusive than observed in the past. These results might depend on earlier referral of less symptomatic patients and might explain the recently reported decrease in IPG sensitivity for proximal DVT. [ABSTRACT FROM AUTHOR]

Plasma thrombin-antithrombin III (T-AT) complexes are reputed to be an indirect manifestation of thrombin generation, and a role for their determination in the diagnosis of deep vein thrombosis (DVT) has been advocated. In order to evaluate the accuracy of T-AT complexes assay for DVT diagnosis, in 166 consecutive outpatients with clinical suspicion of the disease, plasma concentration of T-AT complexes was measured immediately before venography by means of an enzyme-linked immunosorbent assay kit. The result of the T-AT complexes assay was elevated in 29 of the 48 patients with DVT (sensitivity, 60%). The T-AT complexes levels were within the normal range in 104 of the 118 patients with normal venograms (specificity, 88%). The positive and the negative predictive value were 67% and 85%, respectively. The authors conclude that the T-AT complexes assay is of little value for the diagnosis of DVT in outpatients. [ABSTRACT FROM AUTHOR]

The prevalence of lupus anticoagulant (LA) and antiphospholipid antibodies (APA) in young patients (<45 years) with deep-vein thrombosis (DVT) is not clearly defined yet. We studied 93 consecutive patients (36 males, 57 females; aged 15 to 45) with objectively documented DVT. A control group consisting of 100 normal, sex- and age-matched individuals was also investigated. In all subjects, we evaluated prothrombin time (PT), partial thromboplastin time (PTT), AT III antigen and activity, protein C antigen and activity, free and total protein S antigen and protein S activity, fibrinogen, plas-minogen, heparin cofactor II, plasminogen activator inhibitor (PAI), lupus anticoagulant (LA), and APA. For the assessment of LA, we used the PTT-LA kit (Boehringer Mannheim, Milan, Italy) as a screening test, with mixing studies with the Staclot-PNP kit and the Staclot-LA kit (Boehringer Mannheim, Milan, Italy) as confirmatory procedures. For the detection of APA, we used a commercially available enzyme-linked immunoassay (ELISA) (Asserachrom APA, Boehringer Mannheim, Milan, Italy). History was elicited in all patients to determine if the thrombotic episode was idiopathic or the result of a well-identified risk factor. LA was found in 11 (11.8%) patients. APA were positive in 13 (14%) and borderline in 19 (20.4%) patients. In the control group, no patients were positive for LA or APA, but five exhibited borderline APA levels. LA was significantly more frequent (p = 0.05) in patients with idiopathic DVT than in patients with secondary DVT; no difference was found for APA (p > 0.5). An inherited coagulation defect was found in seven (7.5%) patients. Our data suggest that the presence of LA or APA is associated with an increased incidence of thrombotic manifestation in young patients. Moreover LA is more frequent in patients with idiopathic DVT. Because the incidence of recurrent thrombotic manifestations in patients with LA or APA is estimated to be ∼50%... [ABSTRACT FROM AUTHOR]

The relevance of congenital thrombophilia in the pathogenesis of venous thromboembolism in young patients is still debated. In a case-control study, plasma antigen and activity of antithrombin, protein C, and plasminogen, as well as total and free protein S were measured in a series of 166 consecutive outpatients aged less than 50 years, who underwent contrast venography because of clinically suspected deep-vein thrombosis (DVT). The presence of major acquired risk factors for venous thrombosis was also recorded. The association between DVT and inherited thrombophilia or acquired risk factors was initially described using crude odds ratios (OR). Subsequently, a logistic regression model was used to test their independence. Of the 166 patients included, venography showed an acute DVT in 73 (cases), whereas it was normal in the remaining 93 (controls). Major acquired risk factors were identified in 51 cases and in 20 controls (crude OR: 8.5; 95% CI: 4.1-17.1). Inherited thrombophilia was detected in seven cases and in one control (crude OR: 9.8; 95% CI: 1.2-81.2). Inherited thrombophilia was equally distributed between patients with secondary and idiopathic DVT and was proved to be independent from acquired risk factors in the regression model. Inherited thrombophilia is an independent risk factor for DVT in young patients. However, its prevalence in unselected cases with the first episode of DVT is low. [ABSTRACT FROM AUTHOR]