ABO blood group and the risk of post-thrombotic syndrome.

Post-thrombotic syndrome (PTS) has been associated to DVT recurrence, increased FVIII, inflammatory biomarker plasma levels, and persistence of vein obstruction. These same features have also been widely reported in non-O blood type subjects. Our aim was to investigate the correlation between the incidence of PTS and ABO blood types. Consecutive patients referred to the Department of Medicine of University of Padua between January 2004 and January 2012 following the diagnosis of a first episode of proximal DVT were enrolled. The presence of PTS was assessed via the Villalta scale at predefined time points (3, 6, 12, 18, 24, 36 months). Hazard ratio (HR) for PTS development was calculated in non-O (exposed) vs O blood (unexposed) type patients. Out of 671 eligible patients, 606 were enrolled. Overall, 192 (31.7%) patients developed PTS: 142 (34.5%) non-O and 50 (25.6%) O blood type patients. Individuals with non-O blood group were associated with a significantly higher risk to develop PTS (HR 1.53, 95% CI, 1.05-2.24; p = 0.028) than O group. Non-O blood type might be a risk factor for the development of PTS.

Factor VIIa-antithrombin complex: a possible new biomarker for activated coagulation.

The activation of the extrinsic coagulation pathway occurs after endothelial injury when the tissue factor (TF), a transmembrane protein located outside the vasculature, binds factor VII (FVII) or activated FVII (FVIIa). Once formed, the TF-VIIa complex activates both factor IX and X and initiates the coagulation process. The TF-VIIa complex is inhibited by both TF pathway inhibitor (TFPI) and antithrombin (AT). The interaction between TF-VIIa and AT induces FVIIa-AT complex formation, which is released into the plasma. Because AT reacts with FVIIa only when it is bound to TF, the circulating levels of FVIIa-AT reflect the degree of exposure of TF to blood. Preliminary clinical studies have shown higher plasma levels of FVIIa-AT complex both in patients with a prior arterial or venous thrombotic event. Increased plasma levels of FVIIa-AT have also been reported in a number of other prothrombotic conditions - antiphospholipid antibodies, solid and hematological malignancies, pre-eclampsia (PE), obesity and cardiac surgery. However, most of the studies published so far are retrospective and with a limited sample size. Larger prospective clinical studies are needed to confirm these findings and to assess the prognostic role of this possible new biomarker for activated coagulation.

Extensive Computed Tomography versus Limited Screening for Detection of Occult Cancer in Unprovoked Venous Thromboembolism: A Multicenter, Controlled, Randomized Clinical Trial.

Patients with unprovoked venous thromboembolism (VTE) may harbor occult cancer. Whether an extensive diagnostic work-up for cancer has additional value over a more limited screening for detection of underlying malignancy in these patients is controversial. We performed a randomized multicenter trial to assess if in patients with unprovoked VTE, a computed tomography (CT)-based diagnostic strategy including thoracic, abdominal, and pelvic CT in combination with fecal occult blood test yields a higher cancer detection rate than a nonstandardized testing approach based on physicians' clinical judgment and patients' preferences. Cancer-free patients were followed up for up to 24 months. Of the 195 consecutive patients with unprovoked VTE who were eligible for this investigation, an occult cancer was identified in 10 of the 98 patients (10.2%) randomized to the CT-based strategy, and in 8 of the 97 (8.2%) allocated to the personalized strategy (absolute difference, 2.0%; 95% confidence interval, -7.2-11.1; p = 0.81). During follow-up, cancer was identified in an additional 2 patients in each group. Overall, 7 (7.1%) patients of the CT-based strategy died, as compared with 11 (11.3%) of the personalized strategy, with 2 and 4, respectively, due to cancer. In conclusion, a CT-based strategy in combination with fecal occult blood test does not provide a clinically significant benefit over more limited cancer screening for detecting occult cancer in patients with unprovoked VTE. (ClinicalTrials.gov number, NCT00361647).

Circulating microparticles in umbilical cord blood in normal pregnancy and pregnancy with preeclampsia.

INTRODUCTION: Placenta microthrombi being one of the prevalent recurrent histological findings in women with preeclampsia (PE), it is reasonable to think that the study of coagulation alterations in cord blood could be more informative than that observed in maternal blood. The aim of the present study was to measure different subtypes of microparticles (MP) plasma levels in the maternal peripheral blood at labour and in the venous cord blood of pregnant women with PE compared to those in a group of women without PE. MATERIALS AND METHODS: Thirty-two pregnant women in labour, 16 with and 16 without PE, were enrolled. Blood samples were collected immediately after delivery from cord blood and from maternal peripheral blood. Total, cellular-derived and tissue factor- bearing MP were analyzed using flow-cytometry. Procoagulant activity of MP was assessed using the STA® Procoag PPL assay. RESULTS: Total MP, platelet activated-derived (P-Selectin+), leukocyte-derived and TF+MP were higher in pregnancies complicated by PE as compared with normotensive women (p<0.05). Platelet-derived MP (CD61+) levels were lower in PE than in healthy women and no difference was found in endothelial-derived MP levels between the two groups. The PPL clotting time was significantly shorter in PE compared with controls. When only venous cord blood was analysed, all MP detected were significantly higher in PE than in healthy normotensive women (p<0.05). CONCLUSIONS: MP are very likely involved in the hypercoagulable and pro-inflammatory intravascular reactions during PE. Prospective studies in a larger population are needed to define the clinical meaning of MP measurement in the PE setting.