The Wells rule and D-dimer for the diagnosis of isolated distal deep vein thrombosis.

BACKGROUND: Pretest clinical probability with the Wells rule and D-dimer have been widely investigated for the diagnosis of symptomatic proximal deep vein thrombosis (DVT) of the lower limbs, but they have not been formally tested for symptomatic isolated distal DVT diagnosis. OBJECTIVE: To evaluate the diagnostic accuracy of the Wells rule and D-dimer for isolated distal DVT. DESIGN, SETTING, AND PATIENTS: This was a single-center, cross-sectional study including 873 consecutive outpatients with suspected DVT, in whom pretest clinical probability determination, D-dimer determination (STA Liatest; cut-off of < 500 ng mL(-1) ) and complete compression ultrasonography of both lower limbs were performed. RESULTS: The isolated distal DVT prevalence was 12.4% (90/725). The sensitivity of the Wells rule for isolated distal DVT was 47% (95% confidence interval [CI] 36-57%), the specificity was 74% (95% CI 70-77%), and the negative and positive predictive values were 91% (95% CI 88-93%) and 20% (95% CI 15-26%), respectively. Patients with isolated distal DVT had higher D-dimer levels than patients without DVT (1759 ± 1576 vs. 862 ± 1079 ng mL(-1) , P = 0.0001). D-dimer was negative in 13 patients with isolated distal DVT. D-dimer sensitivity and specificity for isolated distal DVT were 84% (95% CI 75-91%) and 50% (95% CI 46-54%), respectively, with a negative predictive value of 96% (95% CI 93-98%). In patients with low pretest clinical probability, the D-dimer negative predictive value was 99% (95% CI 95-100%). CONCLUSION: In clinically suspected DVT with negative proximal compression ultrasonography, pretest clinical probability with the Wells rule has a low diagnostic accuracy for isolated distal DVT. D-dimer has a better negative predictive value, but alone it does not exclude isolated distal DVT. In patients with low pretest clinical probability, D-dimer had a negative predictive value of > 95% for isolated distal DVT.

Spectrum of F8 gene mutations in haemophilia A patients from a region of Italy: identification of 23 new mutations.

SUMMARY: Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by a lack or decrease of coagulation factor VIII activity. The molecular diagnosis of HA is challenging and a variety of different mutations have been identified throughout the F8 gene. Our aim was to detect the causative mutation in 266 HA patients from Emilia-Romagna region (Italy) and in all suspected carriers. Molecular analysis of F8 in 201 HA patients (152 index cases) was performed with a combination of several indirect and direct molecular approaches, such as long distance polymerase chain reaction, multiplex ligation-dependent probe amplification, denaturing high performance liquid chromatography and direct sequencing. The analysis revealed 78 different mutations, 23 of which were novel, not having been reported in national or international databases. The detection rate was 100%, 86% and 89% in patients with severe, moderate and mild HA, respectively. The information provided by this registry will be helpful for monitoring the treatment of HA patients in Emilia-Romagna and also for reliable genetic counselling of affected families in the future.

A web-based registry of inherited bleeding disorders in the region of Emilia-Romagna: results at three and a half years.

A Registry of inherited bleeding disorders was set up in the Region of Emilia-Romagna (RER) to collect information about these diseases and to improve the quality of care. From January 2003, the eight Haemophilia Centres (HC) in the RER began to use computerized clinical records; every 6 months, they send data to Parma Hospital to be processed and published in a website (http://www.registroemofiliarer.it). Great efforts are made to ensure high quality of data. Results of general interest are included in a free 'public area' and more sensitive data in a 'reserved area' (open only to HC and to health authorities). A total of 610 individuals are included: 249 haemophilia A (HA), 63 haemophilia B (HB), 173 von Willebrand's disease, 69 rare bleeding disorders, seven platelet disorders and 49 haemophilia carriers; 131 were genotyped, 188 were tested for inhibitors (16 affected). The most frequent bleeding was haemarthrosis. The joint score (evaluated in 104 haemophiliacs) was higher in severe HA. There were 22 HIV-positive and 182 hepatitis C virus-positive patients (21% have chronic hepatitis, two hepatocellular carcinoma). In 2005, two patients received primary prophylaxis, 47 secondary prophylaxis, four children were on immune-tolerance induction. From 2003 to 2005 the use of recombinant products was greatly increased and the majority of patients received them. The mean clotting factor consumption for prophylaxis was higher than on-demand treatment. The main features of registry are to collect high quality and comprehensive data of all patients followed by HC, to improve quality of care and it's availability on the web.

Recurrent 'migrainelike' episodes in patients with HIV disease.

Recurrent transient neurological deficits have been described in human immunodeficiency virus (HIV)-infected subjects, but their frequency, pathogenesis, and outcome are still unsettled. We describe 10 HIV-infected patients with transient neurological deficits (0.8% of all patients followed in our department during the last decade). All patients were in the advanced stage of immunological disease. None of the clinical or special investigations performed outside of the attacks indicated an underlying structural lesion of the central nervous system. In 80% of these patients, anticardiolipin antibodies were present. The final outcome was unrelated to these transient neurological deficits which, per se, had a benign course. We discuss the possible etiopathogenetic mechanisms of such episodes and suggest that they may be "migrainelike" events, possibly related to transient functional circulatory abnormalities secondary to an immunological antiphospholipid antibody-dependent mechanism.

[Deep venous thrombosis. Evaluation of a non-invasive diagnostic procedure based on compression ultrasonography and measurement of D-dimer plasma levels]. / Trombosi venosa profonda. Validazione di una procedura diagnostica non invasiva basata su ultrasonografia con compressione associata a dosaggio dei D-dimeri plasmatici.

BACKGROUND: Clinical diagnosis of deep venous thrombosis (DVT) of the leg is unreliable. An accurate diagnosis is important for therapeutic decision since anticoagulant treatment, though potentially dangerous, is useless in case of a false positive diagnosis, whereas a false negative diagnosis may lead to withdrawal of an extremely necessary anticoagulation. Contrast venography is still recognized as the gold standard method for the diagnosis of DVT, but in recent years a variety of accurate non-invasive methods has been developed. The ultrasound compression sonography (CUS) is considered a simple non invasive test highly sensitive and specific for proximal DVT in symptomatic outpatients, though non adequately sensitive and specific for isolated calf DVT. Plasma D-dimer levels (DD, fibrin degradation products) have a high negative predictive value for DVT. The aim of this study, performed in outpatients with suspected leg DVT, was to validate, versus venography, a non-invasive, easy to perform and fast diagnostic procedure based on a combination of CUS and D-dimer test. End points of the procedure were: confirmation or exclusion of proximal DVT; suspicion of isolated calf DVT in which case the test would be repeated in a few days to detect any possible proximalization of thrombosis. MATERIALS AND METHODS: Sixty-eight consecutive outpatients, 37 male, with clinically suspected first episode of leg DVT were eligible and examined with CUS, DD test and venography. RESULTS: The results showed that the diagnostic procedure under examination has a high sensibility and specificity for DVT. CONCLUSIONS: It can thus be recommended as routine diagnostic procedure in symptomatic outpatients with suspected DVT reserving venography special cases only.

Persistent B19 parvovirus infections in haemophilic HIV-1 infected patients.

B19 infection can be acquired by transmission with blood factors in patients with congenital bleeding disorders, requiring clotting factor concentrates. In immunodeficient patients, the failure of immunity to clear B19 virus may produce persistent infections. The presence of B19 DNA in blood samples from seven haemophilic patients with concomitant HIV-1 infection was studied over a period of three-to-four years. Dot blot hybridization assays with DNA and RNA probes were used to detect medium high viremias, and polymerase chain reaction (PCR) to detect very low viremic titres. Three patients were negative for B19 DNA in all the blood samples, while four patients were persistently positive for B19 DNA. Viral persistence, which in one patient was detected throughout the study period (40 months), occurred at low titre in all four positive patients with some recurrent increases in viral titre. In the four patients persistently positive for B19 DNA, acute or chronic clinical symptoms and signs that could be associated with B19 were not noted when virus was present at low titre (B19 DNA detectable only by PCR). When patients had a higher viral titre (B19 DNA detectable by dot blot hybridization) acute manifestations (aplastic crisis, Fifth disease, fevers, pneumonitis) were found.

Prevalence of infection with the hepatitis C virus among Italian hemophiliacs before and after the introduction of virally inactivated clotting factor concentrates: a retrospective evaluation.

In July 1985, all coagulation factor concentrates were withdrawn from the market in Italy and replaced with virally inactivated concentrates. A retrospective survey comparing the prevalence of the antibody to the hepatitis C virus (anti-HCV) in hemophiliacs multitransfused with nonvirally inactivated concentrates until 1985 with that in previously untreated hemophiliacs transfused exclusively with virally inactivated concentrates since 1985 has been conducted in 9 Italian hemophilia centers. The centers, which follow about one-fourth of all the Italian hemophiliacs, provided information about 708 patients infused for the first time before 1985 (group A) and 80 patients infused for the first time between 1985 and 1991 (group B). The prevalence of anti-HCV was 83% (591/708) in group A and 6% (5/80) in group B. For the 5 anti-HCV-seropositive patients from group B, dry heating, hydrophobic interaction chromatography plus dry heating (2 patients), hot vapor and pasteurization were the virucidal methods used for the concentrates implicated in HCV transmission. In the case associated with pasteurization, there is the possibility of intrafamilial transmission of HCV. It appears from this retrospective analysis that there has been a substantial reduction in the risk of HCV transmission since the adoption of virucidal methods. However, these methods do not eliminate completely the risk, which might be further reduced by the recent adoption of anti-HCV screening for plasma donations used to manufacture concentrates.

Protease activities, as well as plasminogen activators, contribute to the "lytic" state during orthotopic liver transplantation.

High levels of tissue plasminogen activator (t-PA) have been reported to be the main component of the high fibrinolytic activity measured in patients during orthotopic liver transplantation. However, a previous study of our group suggested that specific t-PA may not completely account for the massive fibrinolytic activities recorded. In the present study we investigated the fibrinolytic patterns in 10 consecutive liver cirrhosis patients undergoing OLT. Euglobulin fibrinolytic activity, measured either on physiologic (fibrin plates) or amidolytic substrates, increased as expected during anhepatic and reperfusion phases, but largely exceeded the specific activity of t-PA, as proved by quenching procedures using anti-t-PA antibodies. The presence of plasmin- and trypsin-like amidolytic activities was detected in native plasmas at the end of anhepatic and reperfusion phases, together with decreased levels of protease inhibitors, especially alpha 1 Antitrypsin. In conclusion, the hyperfibrinolytic pattern recorded in the central OLT phases is not only attributable to an increased t-PA concentration, and is better described as a complex "lytic" state also including the presence of free proteases (plasmin- and trypsin-like), with limited participation of u-PA. Although t-PA increase is probably the main mechanism of stimulation of the fibrinolytic system during OLT, actual and not just potential proteolytic activities can be found in this condition independent of the occurrence of major hemorrhagic complications.

Detection of two missense mutations and characterization of a repeat polymorphism in the factor VII gene (F7).

The 3' portion of the coagulation factor VII gene, containing the activation and serine protease domains, was investigated in four subjects with factor VII deficiency by temperature gradient gel electrophoresis and sequencing of polymerase chain reaction (PCR) products. Molecules displaying an altered melting behaviour were detected in three subjects, and direct sequencing showed two mutations. A G-to-T transversion causing a missense mutation, Cys-310 to Phe, suppresses a disulphide bond conserved in the catalytic domain of all serine proteases. This mutation, which in the homozygous form causes a severe reduction in protease activity (4%), was found in two patients from different Italian regions. A G-to-A transition, which gives rise to a missense mutation, Arg-304 to Gln, and is associated with the factor VII padua variant, was found in the heterozygous form in a subject also affected by von Willebrand disease. Two polymorphic alleles, which differ in one repeat monomer element, were precisely mapped in a region spanning the exon-intron 7 border of the factor VII gene and studied in families with factor VII or X deficiency.

Modulation of arachidonate metabolite generation in human blood by oral defibrotide.

Acute intravenous administration in man of defibrotide (CAS 83712-60-1), a polynucleotide derivative, induces increase of 6-keto-PGF1 alpha and PGE2 production from appropriately stimulated whole blood. In the present study including acute and chronic experiments, defibrotide (Prociclide) orally administered during two weeks to healthy volunteers significantly increased the amounts of 6-keto-PGF1 alpha generated after appropriate stimulation in whole blood and in a neutrophilic leukocytes-platelet suspension. Similar effects were observed for PGE2, while TXB2 production was unchanged. Furthermore, platelet aggregation induced by calcium ionophore A23817 and production of leukotriene B4 from whole blood and isolated polymorphonuclear neutrophils were inhibited. The observed results suggest that defibrotide is biochemically active also by the oral route although the pharmacological and clinical value of the observed changes needs to be assessed.

A HindIII RFLP and a gene lesion in the coagulation factor VIII gene.

The presence and inheritance of restriction fragment length polymorphisms (RFLPs) and gene lesions in the coagulation factor VIII gene were investigated in 15 hemophilia families. An abnormal HindIII 2.6-kb band, previously detected in a severe hemophiliac, was observed in a not severely affected patient and also in the normal gene of a woman carrying a hemophilic gene in which the lesions was found. The TaqI site in exon 24 of this defective gene was removed by a C to T transition causing an amino acid change (Arg----Gln). Very low amounts of factor VIII activity and antigen were detected in the severely affected grandson. The presence of the HindIII 2.6-kb fragment in both normal and pathological genes indicates that a factor VIII RFLP without functional meaning was found. Its frequency, determined in 60 chromosomes, is 0.18. Double digestions enabled us to map the polymorphic site 3' to the exon 19.

Non-HLA lymphocytotoxic antibodies in HIV-seropositive and HIV-seronegative hemophiliacs.

We tested serum samples from 11 HIV-seropositive and 32 HIV-seronegative Italian patients with hemophilia A or B for the presence of lymphocytotoxic antibodies (LCTAs). No patients had the acquired immune deficiency syndrome and all had received over many years heat-untreated commercial clotting factors. LCTAs directed mainly to B cells, were significantly present in 5/6 HIV-seropositive patients with hemophilia A and in 5/5 HIV-seropositive patients with hemophilia B. The presence of LCTAs in HIV-seronegative hemophiliacs was significantly correlated with both a decrease of T cells and an increase in serum levels of IgG and IgM.