Frequent off-label use of fondaparinux in patients with suspected acute heparin-induced thrombocytopenia (HIT) – findings from the GerHIT multi-centre registry study

Introduction

In life-threatening immune heparin-induced thrombocytopenia (HIT), treatment with an approved non-heparin anticoagulant is essential. However, off-label use with fondaparinux has been reported in the literature. The study aim was to collect data on “real-life” management of patients with suspected acute HIT regarding diagnostic and therapeutic strategies.

Patients and Methods

In a national multi-centre registry study, patients with a 4 T’s HIT-probability score of ≥ 4 points and treatment with at least one dose of (A)rgatroban, (L)epirudin, (D)anaparoid, or (F)ondaparinux were retrospectively evaluated.

Results

Of 195 patients, the 4 T’s scores were 4/5/6/7/8 points in 46 (23.6%)/50 (25.6%)/74 (38.0%)/13 (6.7%)/7 (3.6%) patients, respectively. During heparin therapy, 47 (24.1%) thromboembolic events, 5 (2.6%) skin lesions, 1 (0.5%) amputation, 24 (12.3%) Hb-relevant bleedings, and 2 (1.0%) fatalities occurred. A functional heparin-induced platelet activation assay was performed in 96.9%, a platelet factor 4/heparin-dependent enzyme immunoassay in 89.2%, a particle gel immunoassay in 12.3%, and a serotonin-release assay in none of the patients. Argatroban was used in 16.4%, lepirudin in 2.1%, danaparoid in 23.6%, fondaparinux in 40.0% of the patients; the sequential therapy strata were: AF (5.6%), DA (5.6%), DF (2.6%), DL (2.1%), ADF (1.5%), and DFL (0.5%).

Conclusions

The current diagnostic laboratory strategy for suspected HIT is mostly (> 96%) based on the recommended 2-step strategy (immunoassay plus functional assay). However, there is a wide fondaparinux off-label use (up to 50.3%) for suspected HIT, even in those patients with a high clinical pretest probability. Efficacy and safety of fondaparinux for HIT-treatment require further evaluation.     

A clinical-laboratory approach contributing to a rapid and reliable diagnosis of heparin-induced thrombocytopenia

Introduction

Heparin-induced thrombocytopenia (HIT) remains a very challenging diagnosis. The first objective of this study was to compare the performance of the ID-H/PF4 PaGIA^® with the Asserachrom^® HPIA ELISA. The main purpose was to evaluate the diagnostic utility of the combination of the H/PF4 PaGIA^® with the clinical “4T's” score as a screening strategy.

Materials and Methods

102 patients with clinical suspicion of HIT were classified into risk groups using the 4T's score. The presence of HIT antibodies was assessed by two immunoassays and confirmed by a functional flow cytometric assay.

Results

Comparison of the ID-H/PF4 PaGIA^® with the Asserachrom^® HPIA ELISA demonstrated a comparable technical performance, being an excellent screening test to rule out HIT (negative predictive value or NPV = 100%). According to the 4T's score, HIT was excluded in all low risk patients (NPV = 100%). ELISA optical density levels were significantly different between all risk groups (P-values < 0.01). In contrast, due to the low positive predictive value (22%) and weak positive likelihood ratio (2.6), a positive ID-H/PF4 PaGIA^® result did not considerably increase the probability of HIT.

Conclusion

Our study confirms the combination of the 4T's score with the ID-H/PF4 PaGIA^® as a reliable strategy to rule out HIT. Yet, confirming positive ID-H/PF4 PaGIA^® results by flow cytometry within 1-2 h after blood sampling remains necessary. This novel clinical-laboratory approach can contribute in a rapid and reliable way to the definite diagnosis of HIT.     

Interleukin-10 promoter microsatellite polymorphisms influence the immune response to heparin and the risk of heparin-induced thrombocytopenia

Introduction

Heparin-induced thrombocytopenia (HIT) results from an atypical immune response with synthesis of IgG antibodies (Abs) to platelet factor 4/heparin complexes (PF4/H), and probably involves both B and T cells. We investigated whether 3 single nucleotide polymorphisms (SNPs), rs1800896 (− 1082G/A), rs1800871 (− 819C/T) and rs1800872 (− 592C/A) and the polymorphic CA repeat microsatellites IL10R [5325CA(11_15)] and IL10G [8134CA(14_29)] are associated with the synthesis of Abs to PF4/heparin and HIT.

Materials and methods

Eighty-two patients with definite HIT and two control groups were studied. The first control group (Ab^neg) consisted of 85 patients without Abs to PF4/heparin after cardiopulmonary bypass (CPB). The second control group (Ab^pos) consisted of 84 patients who had developed significant levels of PF4-specific antibodies after CPB, but without HIT.

Results

Allele frequencies of the 3 SNPs were similar in HIT patients and controls. Fourteen alleles in IL10G (G16 to G29) and 3 alleles in IL10R (R13 to R15) were defined. The short G20 allele of IL10G was more frequent in Ab^neg patients (8.2%) than in Ab^pos (2.9%) and HIT patients (3%). It thereby appeared to protect against developing Abs to PF4/heparin (OR 0.29; 95% CI [0.12-0.70], p = 0.006). Combined haplotypes cH1/cH8 comprising the short G20 + R13 alleles were less frequent in HIT (OR 0.33; 95% CI [0.11-0.97], p = 0.036), and levels of Abs to PF4 in Ab^pos patients were lower in cH1/cH8 subjects (p = 0.019).

Conclusion

These results suggest that IL10 promoter microsatellite polymorphisms might influence the immune response against PF4/heparin and the risk of HIT.     

Incidence and time course of asymptomatic deep vein thrombosis with fondaparinux in patients undergoing total joint arthroplasty

Introduction

There are many reports concerning fondaparinux prophylaxis of asymptomatic deep vein thrombosis (DVT) after total hip arthroplasty (THA) or total knee arthroplasty (TKA), but little is known about the time course of aymptomatic DVT development during the administration of fondaparinux. The aim of the present study was to define the incidence and time course of aymptomatic DVT development during administration of fondaparinux, and to assess the efficacy of fondaparinux in resolving DVT.

Materials and Methods

We studied consecutive71 patients who underwent THA surgery, and 30 patients who underwent TKA surgery with fondaparinux prophylaxis. Patients received once-daily subcutaneous injections of 2.5 mg of fondaparinux for 14 days after surgery. DVT was diagnosed by ultrasonography, and it was scheduled on the day of surgery on day 1, day 4, and day 14 after surgery.

Results

In patients who received fondaparinux for 14 days after THA surgery, the incidence of DVT was 0% on the day of the surgery, 13.6% at day 1, 27.1% at day 4, and 11.9% at day 14. In patients who received fondaparinux for 14 days after TKA surgery, the incidence of DVT was 4.2% on the day after surgery, 50.0% at day 1, 58.3% at day 4, and 20.8% at day 14. The incidence of DVT after THA or TKA surgery at day 14 was significantly reduced compared to that at day 4.

Conclusion

The incidence of asymptomatic DVT up to day 4 was high, but with 14 days continued treatment of fondaparinux, the incidence of asymptomatic DVT occurring at postoperative day 4 was significantly reduced at day 14.     

Eosinophil count predicts mortality following percutaneous coronary intervention

Introduction

Several inflammatory markers have been shown to be independent predictors for both the development of clinically significant atherosclerosis and for adverse outcome in patients with symptomatic coronary artery disease (CAD). We investigated the prognostic role of eosinophil count in low to intermediate risk patients with CAD.

Methods

We studied 909 patients admitted for elective or urgent percutaneous coronary intervention (PCI) from April 2002 to December 2004, and measured pre-procedural total and differential white blood cell (WBC) counts. Inter-tertile WBC differences in short (6 months) and long term (up to 74 months) mortality were analysed after adjusting for differences in baseline characteristics.

Results

Over a median period of 54 months (inter-quartile range 47-65), a total of 138 deaths (15.2%) occurred, of which 24 were in the first 6 months of follow-up. Cox regression analysis showed that high pre-procedural eosinophil count (top tertile) was associated with improved outcome within the first 6 months (OR = 0.23 [0.06-0.84]; p = 0.03) but after this period there was an increased risk of mortality (OR = 2.21, [1.26-3.88]; p = 0.006).

Conclusions

Eosinophil count is a novel biomarker for risk stratification of CAD patients, which was associated initially with reduced mortality, but after 6 months with increased mortality.     

Incidence and characteristics of asymptomatic distal deep vein thrombosis unexpectedly found at admission in an Internal Medicine setting

Introduction

Lower limb deep vein thrombosis (DVT) is the most frequent clinical manifestation of venous thromboembolism (VTE) and can involve proximal or distal veins. Distal DVT (dDVT) is often asymptomatic and data about its incidence and prognosis are scanty, especially in high risk medical inpatients. Therefore, no consensus exists on the value of detecting and treating dDVTs. Aim of study was to evaluate incidence and characteristics of asymptomatic isolated dDVT at admission in an Internal Medicine department.

Materials and methods

Consecutive patients hospitalized for acute medical illnesses, in whom VTE was not the admission diagnosis, underwent Doppler Ultrasonography. For all patients with dDVT standard treatment with therapeutic doses of low molecular weight heparin or fondaparinux was proposed. Follow-up visits were scheduled at 1, 6 and 12 weeks.

Results

One-hundred-fifty-four patients were enrolled. In 4.5% a proximal DVT and in 16.2% an asymptomatic dDVT were found. Female sex, elevated age and renal and electrolyte abnormalities were significantly associated to dDVT (p = 0.014, p = 0.009 and p = 0.046, respectively). Only low degree of mobility (LDM) was independently associated to dDVT [OR 7.97 (95%CI 2.42-26.27), p = 0.001)]. A high mortality rate, not for VTE-related causes, was found, especially in the first week, among dDVT patients.

Conclusions

We found a high incidence of clinically silent dDVTs. LDM evaluation could be useful to select patients at high risk in whom to perform a search for dDVT.     

Combined use of the high heparin step and optical density to optimize diagnostic sensitivity and specificity of an anti-PF4/heparin enzyme-immunoassay

Background

IgG-specific anti-PF4/heparin enzyme-immunoassays (EIAs) are sensitive but not specific for platelet-activating antibodies, the cause of heparin-induced thrombocytopenia (HIT). Two features of EIA reactivity predict for presence of HIT antibodies - the magnitude of a positive result (in optical density [OD] units) and the inhibition of reactivity at high heparin concentrations - but their combined utility remains uncertain.

Objective

To determine for an IgG-specific EIA how the OD values of a positive reaction and its inhibition by high heparin can be optimally combined.

Methods

We screened 1,000 consecutive patients with suspected HIT using an IgG-specific PF4/heparin in-house EIA with and without high heparin (100 IU/mL); and by the heparin-induced platelet activation test.

Results

Platelet-activating antibodies were rarely detected (< 0.2%) when the IgG-specific EIA was negative at the conventional cut-off (OD, 0.5). However, an OD cut-off of 1.0 resulted in an unacceptable loss of sensitivity (14/83 = 17%) for detecting platelet-activating antibodies. The high heparin step increased specificity for platelet-activating antibodies from 72% to 89% without loss of sensitivity when applied to weak-positive sera (OD ≤ 1.0). However, decreased sensitivity was observed with strong-positive sera (OD > 1.0): 11/69 such sera (16%) that did not show > 40% inhibition by high heparin nevertheless contained platelet-activating antibodies.

Conclusion

Specificity of an IgG-specific EIA for detecting platelet-activating antibodies can be optimized by applying the high heparin inhibition step to weak-positive reactions (0.5- ≤ 1.0 OD). However, applying the high heparin inhibition step to strong-positive reactions (> 1.0 OD) in our in-house assay risks falsely classifying a serum as negative for platelet-activating antibodies.     

Compliance of antithrombotic management at a tertiary paediatric hospital with international guidelines: a 100-Day audit

Background

Increased levels of factor VIII occur as a response to vascular injury and/or inflammation, and may increase thrombotic risks. In contrast, factor VIII deficiency poses a major hemostatic challenge. The role of factor VIII in modulating hemostasis/thrombosis was investigated in plasma models of hypocoagulable and hypercoagulable state using thrombin generation (TG) assay.

Methods

TG was performed in undiluted/diluted control, FVIII-deficient, FVIII-deficient with low antithrombin (AT activity, ~ 59%), and factor XI-deficient plasma samples using relipidated tissue factor (TF, 2 pM) or dilute Actin as activators. The impact of elevated FVIII on TG was simulated by adding Humate-P (0 to 3 U/ml) to the above plasma samples. In fondaparinux (1 μg/ml) treated plasma with normal or lower AT activity effects of Humate-P vs. 60 nM of recombinant activated factor VII (rFVIIa) were also evaluated.

Results

Humate-P increased TG concentration dependently in undiluted and diluted control plasma with TF activation. With Actin activation, only the concentration dependent shortening of lag time, but no change in peak thrombin was observed. In FVIII-deficient, FVIII-deficient with low AT, and FXI-deficient samples, 3 U/ml of Humate-P increased TG, and decreased its onset with either activator. The reduced peak thrombin due to fondaparinux was reversed with Humate-P (3 U/ml) more than with rFVIIa. Elevated FVIII levels seem to favor intrinsic tenase formation and antagonize fondaparinux because anti-FIXa aptamer added to fondaparinux effectively attenuated TG.

Conclusion

Elevated FVIII supports the propagation of TG via intrinsic tenase formation under low TF condition, factor XI deficiency or in the presence of fondaparinux.     

Inhibition of the renin-angiotensin system downregulates tissue factor and vascular endothelial growth factor in human breast carcinoma cells

Introduction

The renin-angiotensin system (RAS) promotes angiogenesis and growth of neoplastic cells. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor AT1 blockers may protect against cancer. Tissue factor (TF), for its involvement in tumor growth, angiogenesis, and metastasis is considered a hallmark of cancer progression.In this study we evaluated whether RAS blockade modulates TF constitutive expression by the metastatic breast carcinoma MDA-MB-231 cell line.

Materials and Methods

Cell TF activity was assessed by one stage clotting time, TF and VEGF antigens and mRNA levels by ELISA and RT-PCR, respectively. AT₁ was detected by flow-cytometry and angiotensin-II levels by EIA.

Results

Captopril reduced in a concentration-dependent way both the strong constitutive TF activity (983.2 ± 55.2 vs. 686.7 ± 135.1 U/5 × 10⁵ cells with 10 μg/ml captopril) and antigen (32.3 ± 5.9 vs. 13.2 ± 6.6 ng/ml) in MDA-MB-231. Similar results were observed with enalapril.AT1 was present on cell membrane and losartan, a competitive inhibitor of AT1, reduced TF expression to a degree similar as that exerted by ACE inhibitors. Moreover, captopril and losartan downregulated the constitutive mRNA TF expression by ~ 35%. Similar results were observed with anti-AT1 and angiotensin II antibodies. In addition, the constitutive VEGF antigen and mRNA levels were reduced in the presence of captopril or losartan, and an anti-VEGF antibody downregulated cell TF activity by ~ 40%.

Conclusions

These results could, at least in part, contribute to the discussion about the possible effects of ACE inhibitors and AT1 receptor antagonists in malignancy, and offer new clues to support their use for tumor control.     

Physiological changes in membrane-expressed platelet factor 4: Implications in heparin-induced thrombocytopenia

Background

Many heparin-induced thrombocytopenia (HIT) antibodies cause platelet activation in the serotonin release assay (SRA) in the absence of heparin. This in vitro observation may help unravel the mechanism of delayed-onset HIT, where seropositive patients develop thrombocytopenia and associated thrombosis after cessation of heparin.

Objective

Studies were conducted to examine the relationship between platelet environment, surface PF4 expression, and the extent of heparin-independent platelet activation in the SRA.

Methods

Ex vivo platelets were washed and labeled for SRA, then used either before or after 45 minutes of recovery at 37 °C. HIT antibody-mediated serotonin release in the absence of heparin was compared to the extent of surface staining of the platelets with fluorescent anti-human PF4 antibodies.

Results

Handling of platelets for in vitro studies resulted in transient expression of surface PF4, and it was during this interval that platelets were most sensitive to activation by HIT antibodies in the absence of heparin. Heparin-independent platelet activation was attenuated when SRA-positive specimens were retested after platelets were incubated 45 minutes at 37 °C. Surface PF4 expression was diminished on the rested platelets, compared to the same platelets labeled immediately after handling. Thus compared to rested platelets, mildly activated platelets had elevated surface PF4 expression and a higher level of HIT antibody-mediated, heparin-independent platelet activation.

Conclusion

Surface expression of PF4 reflects HIT antigen presentation, and varies with the physiological state of platelets. Thus there can be differences in HIT antibody target availability among patients which may explain the variability in consequences of HIT antibody seropositivity.     

Accuracy of a portable international normalized ratio monitor for patients receiving a low molecular weight heparin as a bridge pending full oral anticoagulant efficacy

Background

Point of care (POC) devices measuring the international normalized ratio (INR) are accurate for patients with stable disease, but their efficiency has not been prospectively assessed during the “bridging period” when patients are receiving a low molecular weight heparin (LMWH) on top of a vitamin K antagonist (VKA) until the target INR is reached.

Methods

188 dual INR measurement using the POC (INR_POC) and the laboratory (INR_lab) at the same time were consecutively determined : 69 in patients receiving LMWH + VKA (bridging group) and 119 in patients receiving only a VKA (control group). INRpoc was compared to INR_lab.

Results

Test strip failure rate was higher in the bridging group than in the control group (29% vs 4% ; p < 0,001).In successful tests, POC accuracy was not modified by LMWH administration: the correlation coefficients between POC and lab INR values for the bridging group and the control group were 0,81 and 0,87 respectively, and the relative measure of divergence (RMD = INR_lab - INR_poc / INR_lab) was lower in the bridging group than in the control group (4 ± 7% vs 10 ± 14%; p = 0,02). Finally, clinically relevant agreement between POC and laboratory was of 90% in the bridging group and 92.1% in the control group (p = 0.6).

Conclusion

With the POC used (INRatio), in patients receiving LMWH when the POC gives a result, it is as accurate as in patients not receiving a LMWH.     

The brain-derived neurotrophic factor (BDNF) polymorphism Val66Met is associated with neither serum BDNF level nor response to selective serotonin reuptake inhibitors in depressed Japanese patients

Background

We investigated the relationship between a brain-derived neurotrophic factor (BDNF) polymorphism (Val66Met) and the clinical response of patients with major depressive disorder to selective serotonin reuptake inhibitors (SSRIs; here, paroxetine and sertraline). In addition, serum BDNF levels in these patients were considered together with the clinical response.

Methods

A total of 132 patients who met the DSM-IV criteria for major depressive disorder were enrolled in the study. 54 of these patients were male and 78 were female (age range, 20-74 years; mean ± S.D., 51 ± 15). The patients' clinical improvement was evaluated using the 17-item Hamilton Rating Scale for Depression (HAMD-17) before (T0) and at 8 weeks after the administration of SSRI treatment (T8). Patients with at least a 50% decrease in the HAMD-17 score were classified as responders.

Results

No correlation was observed between the BDNF Val66Met polymorphism and response to SSRIs or between the BDNF Val66Met polymorphism and serum BDNF levels at T0. An inverse correlation was found between serum BDNF levels and HAMD-17 scores at T0.

Conclusions

These results suggest that the BDNF Val66Met polymorphism is independent of both the response to SSRI treatment and serum BDNF levels. The findings in the present study reconfirm that the serum BDNF level is a state biomarker for depression.     

Differential Effects of Fondaparinux and Bemiparin on Angiogenic and Vasculogenesis-like processes

Introduction

Conventional therapy for venous thromboembolism or acute coronary syndrome involves the administration of glycoanticoagulants (heparins) or oligosaccharides (fondaparinux). We evaluated the effects of such drugs on angiogenesis and vasculogenesis-like models.

Materials and Methods

Human umbilical vein endothelial cells or human endothelial progenitor cells were treated with bemiparin, fondaparinux or unfractionated heparin, at concentrations reflecting the doses used in clinical practice. After 24 h, cell viability, proliferation, tubule formation and angiogenic molecular mechanisms, such as activation of the serine/threonine kinase AKT, were assessed. In vivo angiogenesis was studied using a Matrigel sponge assay in mice.

Results

Bemiparin gave a significant decrease of in vitro angiogenesis as shown by the reduction of endothelial cell tubule network, while both fondaparinux and unfractionated heparin did not show any significant effect. In assays of Matrigel sponge invasion in mice, unfractionated heparin was able to stimulate angiogenesis and, conversely, bemiparin inhibited angiogenesis. Furthermore, both bemiparin and fondaparinux caused a significant reduction in an in vitro vasculogenesis-like model, as demonstrated by the decrease of tubule network after co-seeding of endothelial progenitor cells and human umbilical vein endothelial cells. In addition, unfractionated heparin but not bemiparin was able to increase AKT phosphorylation.

Conclusions

In in vitro experiments, bemiparin was the only drug to show an anti-angiogenic and vasculogenic-like effect, unfractionated heparin showed only a trend to increase in angiogenesis assay and fondaparinux affected only the vasculogenesis-like model. Notably, the in vivo experiments corroborated these data. Such results are important for the choice of a patient-tailored therapy.     

Liporetro-D-peptides - a novel class of highly selective thrombin inhibitors

Introduction

Plasma serine protease thrombin plays a key role in coagulation, haemostasis and thromboembolic diseases. Direct thrombin inhibitors could be beneficial for future anticoagulant therapy. We have synthesized and studied liporetro-D-peptides - efficient thrombin inhibitors resistant to enzymatic degradation.

Materials and Methods

Compounds X-D-Arg-D-Phe-OMe, where X = residue of lauric or myristic acid or 9-fluorenylmethoxycarbonyl, have been synthesized by conventional peptide synthesis in solution and their comparative inhibitory analysis in relation to thrombin, factor X, plasmin and trypsin has been conducted.

Results

Modification of the synthetic liporetro-D-peptides with the myristic acid residue was the most successful one. This modification has dramatically increased the inhibition efficacy (Ki = 0,17 μM) and selectivity toward the chosen target enzyme, thrombin, in comparison to factor X, plasmin and trypsin (more than 600, 900, and 5000-fold, respectively).

Conclusions

Our findings establish an important role of the fatty moiety in the structure of peptide inhibitors with regards to their potency and selectivity toward thrombin.     

Sustained enhancement of residual platelet reactivity after coronary stenting in patients with myocardial infarction compared to elective patients

Introduction

Elevated platelet reactivity despite antiplatelet therapy is associated with an increased cardiovascular risk after percutaneous coronary interventions. Current guidelines recommend uniform antiplatelet maintenance regimen after percutaneous coronary interventions for patients with myocardial infarction and elective patients. We sought to demonstrate that there is a persistent enhancement of residual platelet reactivity after myocardial infarction, requiring an intensified antiplatelet maintenance therapy.

Materials and Methods

A total of 66 patients after coronary stenting for myocardial infarction (n = 36) or elective coronary stenting (n = 30) were included in this prospective, controlled study. Platelet reactivity to adenosine-5-diphosphate and arachidonic acid under treatment with clopidogrel (75 mg) and acetyl salicylic acid (100 mg) were assessed 48 hours and 30 days after coronary stenting using light transmission aggregometry and multiple electrode platelet aggregometry (Multiplate analyzer) simultaneously.

Results

Fourty-eight hours after coronary stenting all measures of residual platelet reactivity were significantly elevated in the infarction group. After a mean follow up of 37 days, residual platelet reactivity to adenosine-5-diphosphate was still consistently elevated, albeit statistically not significant. Contrarily, residual platelet reactivity to arachidonic acid significantly decreased and returned to normal by the time of follow up. Regression analyses revealed myocardial infarction, C-reactive protein and fibrinogen as predictors of enhanced platelet reactivity 48 hours after coronary stenting.

Conclusions

Patients undergoing coronary stenting for acute myocardial infarction exhibit an enhancement of residual platelet reactivity sustaining for at least 48 hours following coronary stenting. This finding provides a rationale for a continued intensified antiplatelet therapy after myocardial infarction.     

Elevated numbers and altered subsets of procoagulant microparticles in breast cancer patients using endocrine therapy

Introduction

Microparticles (MP) can be elevated in cancer and thromboembolic disease. We hypothesized a role for MP in the hypercoagulable state in breast cancer patients using endocrine therapy, in whom both cancer and the use of endocrine therapy are independent risk factors for the development of thrombosis.

Design and methods

Plasma samples were collected from 40 breast cancer patients using endocrine therapy (20 patients without metastases receiving adjuvant therapy and 20 patients with metastatic disease treated in a palliative setting) and from 20 female healthy controls. The endocrine therapy used was either an anti-estrogen or an aromatase inhibitor. Numbers and cellular origin of MP subsets were analyzed by flowcytometry. MP-associated procoagulant activity was measured using a thrombin generation assay using conditions that allow analysis of MP induced thrombin generation.

Results

Breast cancer patients using endocrine therapy had higher levels of MP positive for Annexin V (median 10000 vs 6500 × 10E6/l), P-selectin (330 vs 200 × 10E6/l), tissue factor (33 vs 15 × 10E6/l), and of MP derived from platelets (CD41) and leukocytes (CD45). Thrombin generation in plasma was dependent on the presence of MP and thrombin generation performed after addition of isolated MP to normal plasma showed a higher endogenous thrombin potential (1105 vs 1029 nM.min) in breast cancer patients. No differences were observed in MP levels and thrombin generation parameters between the metastatic and adjuvant group.

Conclusion

Breast cancer patients using endocrine therapy have an increased MP number and a higher MP-dependent thrombin generation, irrespective of the presence of metastatic disease. Altered MP subset characteristics in these patients, especially the higher number of (activated) platelet derived MP and leukocyte derived MP, may in part explain a heightened procoagulant state in breast cancer patients using endocrine therapy.     

Association of elevated NTproBNP with recurrent thromboembolic events after acute pulmonary embolism

Introduction

N-Terminal Pro-Brain Natriuretic Peptide (NTproBNP) is a predictor of adverse short-term clinical outcomes in patients with acute pulmonary embolism (APE), but its long-term prognostic value remains largely undefined. The aim of this study was to assess the value of plasma NTproBNP with regard to recurrent venous thromboembolism (VTE).

Materials and Methods

NTproBNP levels were measured in 224 consecutive patients with the first episode of acute pulmonary embolism occurring from January 2005 through October 2010. Patients were categorized into two groups by NTproBNP reference range. Follow-ups were performed at 3, 6, and 12 months and yearly thereafter. The primary end point was symptomatic, recurrent fatal or nonfatal VTE.

Results

NTproBNP was elevated in 158 (70.5%) patients and not elevated in 66 (29.5%) patients. After a mean follow-up period of 31.0 ± 19.4 months, patients with elevated NTproBNP showed an increased risk of recurrent VTE (20 patients, 12.7%) compared to those without elevated NTproBNP (only 1 patient, 1.5%) (P = 0.009). Of the 7 deaths related to pulmonary embolism, 6 occurred in patients with elevated NTproBNP compared to patients with normal NTproBNP (1 of 7 deaths). In a multivariate analysis stratified by oral anticoagulant treatment duration, elevated NTproBNP was an independent predictor of recurrent VTE (hazard ratio, 9.32; P = 0.02).

Conclusions

Elevated NTproBNP is associated with recurrent VTE in acute pulmonary embolism patients.     

Patients with primary antiphospholipid antibody syndrome and without associated vascular risk factors present a normal endothelial function

Introduction

Primary antiphospholipid antibody syndrome (PAPS) is characterized by venous or arterial thrombosis and positive antiphospholipid antibodies. It is controversial whether PAPS patients have early atherosclerosis. Endothelial dysfunction is an early event in the natural history of atherosclerosis. Aim of our study was to compare endothelial function of patients with PAPS and no associated risk factors with that of age- and sex-matched controls.

Materials and Methods

Patients with PAPS, carefully selected to exclude all known risk factors for cardiovascular diseases, estrogen therapy, pregnancy, intake of drugs affecting endothelial function, vitamins or antioxidants, were included in a case-control study. Controls were age- (± 5 years) and sex-matched subjects with the same exclusion criteria but without PAPS. Flow-mediated dilation of the brachial artery and some plasmatic markers of endothelial and platelet activation were measured. Measures are expressed as mean±SEM.

Results

Twenty cases (mean age 42 ± 4.0 years, 11 females) and 39 controls (mean age 41 ± 2.9, 22 females) were studied. FMD was 5.7 ± 0.8% in cases (95% CI: 4.1 to 7.3) and 6.8 ± 0.5% (5.7 to 7.9) in controls (p = NS). Plasma von Willebrand factor was 128 ± 11.3% and 134.2 ± 16.1% in cases and controls, respectively (p = NS). Soluble P-selectin and soluble CD40L were 94.1 ± 4.9 ng/ml and 0.7 ± 0.1 ng/ml in cases and 87.7 ± 4.0 ng/ml and 1.0 ± 0.2 in controls, respectively (p = NS). In a substudy, circulating progenitor and mature endothelial cells were comparable between the two groups.

Conclusions

Endothelial function in patients with PAPS and no associated risk factors is similar to that of age- and sex- matched controls. These data suggest that the alterations leading to thrombosis in PAPS concern primarily the clotting system.     

The effect of clopidogrel besylate and clopidogrel hydrogensulfate on platelet aggregation in patients with coronary artery disease: a retrospective study

Background

Recently several alternative forms of the original clopidogrel hydrogensulfate (CHS) were spread worldwide. A large amount of such drugs turned out to be clopidogrel besylate (CB). Only three studies, involving healthy volunteers, investigated the antiplatelet effect of CB, whereas its attribute remained unexplored in the case of patients with cardiovascular diseases. This retrospective study aimed to evaluate the difference between the antiplatelet effects of two clopidogrel formulas, CHS and CB, on patients with coronary artery diseases.

Methods

Data of 150 patients with previous CHS treatment were investigated. According to the documentations, the CHS therapy was shifted to CB. 94 patients of the selected population received dual antiplatelet therapy, clopidogrel and aspirin. The antiplatelet effects of CHS and CB were compared by ADP induced platelet aggregation measurements using light transmission aggregometry.

Results

Irrespective of the therapeutic combinations the performed statistical investigations failed to show significant difference (p = 0.30) between the effect of CB (AGGmax_CB: 27.6 ± 13.7%) or CHS (AGGmax_CHS: 29.0 ± 15.3%) on the ADP induced platelet aggregation. Insignificant deviations were found in both forms of clopidogrel salts, either in the lack (AGGmax_CB : 32.5 ± 14,2%; AGGmax_CHS: 34,0 ± 16,1%; p = 0,29) or in the presence of aspirin (AGGmax_CB: 24.7 ± 12,5%; AGGmax_CHS: 26,0 ± 14,1%; p = 0,31).

Conclusion

Our results indicated that both CB and CHS had an identical inhibitory effect on ADP induced platelet aggregation in patients with cardiovascular diseases. Moreover their efficiency showed no overall significant difference in the case of dual antiplatelet therapy with aspirin as well. However there might be an inter- and intraindividual variability between the two clopidogrel formulas.     

Rapid decrease in depressive symptoms with an N-methyl-d-aspartate antagonist in ECT-resistant major depression

Background

Ketamine rapidly improves depressive symptoms in patients with treatment-resistant major depressive disorder (MDD) who do not respond to multiple standard antidepressants. However, it remains unknown whether ketamine is equally effective in patients with MDD who previously also did not respond to electroconvulsive therapy (ECT).

Methods

This study compared 17 patients with treatment-resistant MDD who previously did not respond to ECT and 23 patients with treatment-resistant MDD who had not previously received ECT. All subjects received a single open-label infusion of ketamine (0.5 mg/kg). Patients were evaluated using the Montgomery-Asberg Depression Rating Scale (MADRS) at baseline (60 min before the infusion), as well as at 40, 80, 120, and 230 min after infusion.

Results

Depressive symptoms were significantly improved in the ECT-resistant group at 230 minutes with a moderate effect size (p < .001, d = 0.50, 95% C.I.: 0.21-0.80). At 230 minutes, the non-ECT exposed group showed significant improvement with a large effect size (p < .001, d = 1.00, 95% C.I.: 0.71-1.29).

Conclusion

Ketamine appears to improve depressive symptoms in patients with MDD who had previously not responded to ECT. These preliminary results encourage further investigation with a larger sample size to determine effectiveness compared to other treatment-resistant patients with MDD.