Adverse impact of a high CD4/CD8 ratio in the allograft may be overcome by methotrexate- but not mycophenolate- or posttransplant cyclophosphamide-based graft versus host disease prophylaxis

INTRODUCTION

A high CD4/CD8 T cell ratio in hematopoietic stem cell transplant (HSCT) allografts was observed to predict graft-versus-host disease (GVHD) and non-relapse mortality (NRM) but has not been comparatively examined in settings of various GVHD-prophylaxis regimens.

METHODS

This retrospective monocentric study included all consecutive HSCT performed with peripheral blood stem cells (PBSC) between January 2000 and June 2021. The impact of the graft CD4/CD8 ratio was analyzed in three cohorts with different GVHD-prophylaxis platforms.

RESULTS

In the cyclosporine/mycophenolate-mofetil (CSA/MMF) cohort (n = 294, HLA-matched HSCT), a high (> 75^th percentile) CD4/CD8 ratio was associated with increased overall mortality (HR 1.56; P=0.01), increased NRM (HR 1.85; P=0.01) and GVHD-associated mortality (HR 2.13; P=0.005). In the post-transplant cyclophosphamide (PTCy)/tacrolimus/MMF cohort (n = 113, haploidentical-related or mismatched-unrelated HSCT), a high CD4/CD8 ratio was associated with increased overall mortality (HR 2.07; P=0.04) and aGVHD3-4 (HR 2.24; P=0.02). By contrast, in the CSA/methotrexate (CSA/MTX) cohort (n = 185, HLA-matched HSCT) the CD4/CD8 ratio had no significant impact on any of the investigated endpoints.

CONCLUSION

A high CD4/CD8 ratio in the allograft has an adverse impact on GVHD and survival in CSA/MMF- and PTCy-based HSCT, while MTX-based prophylaxis may largely alleviate this important risk factor.

OS01.5.A Neuron-specific enolase (NSE) and S100 serum levels in patients with active brain metastases from HER2-positive breast cancer treated with trastuzumab-deruxtecan (T-DXd): A biomarker analysis from the TUXEDO-1 trial

Background

T-DXd is a novel antibody-drug conjugate with high activity in HER2-positive metastatic breast cancer. The prospective, single-arm, single-centre phase II TUXEDO-1 trial showed clinically relevant activity of T-DXd in HER2-positive BC pts with active BM with an intracranial response rate of 73.3%. This biomarker sub-study of TUXEDO-1 aimed to investigate changes in the extent of metastases-induced brain damage in patients with and without response to therapy by measuring the serum levels of two proteins constitutively expressed in the human brain and measurable upon brain damage in the blood serum: NSE and S100.

Material and Methods

We assessed serum NSE (sNSE) and serum S100 (sS100) levels in a total of 37 blood samples drawn at cycles 1, 4 and end of treatment (EOT) in all patients of the intent-to-treat population of the TUXEDO-1 trial using commercially available ELISA assays. Intracranial radiological response was centrally assessed by a board-certified neuro-radiologist using RANO criteria. sNSE and sS100 levels were compared between responders and non-responders using the Mann Whitney U test and a significance level of 0.05.

Results

At baseline, we detected no significant difference of sNSE or sS100 levels between T-DXd responders and non-responders, respectively. Baseline median sNSE level was 10.6 ng/ml (interquartile range (IQR) 8.6-12.2) in T-DXd responders as compared with median 12.5 ng/ml (IQR 12.2-12.9) in the non-responder group (n.s.). At cycle 4, corresponding numbers were 8.1 ng/ml in responding patients (IQR 7-11.2) and 12.7 ng/ml (IQR 12.2-12.9) in non-responders, respectively (p=0.009). No differences in sS100 levels were observed between the groups at any time point.

Conclusion

In patients showing intracranial objective response to T-Dxd, sNSE levels were significantly lower at cycle 4 as compared with non-responders, suggesting a reduction in metastases-induced brain damage as a direct treatment effect. sNSE may be a clinically useful biomarker for longitudinal assessment of brain metastasis burden.

Prothrombin Fragment F1+2 Is not Predictive for Recurrent Venous Thromboembolism

It would be important to estimate in advance the risk of recurrent thrombosis. Deficiencies of antithrombin, protein C or protein S, or resistance to activated protein C are associated with a biochemically detectable prethrombotic state. It is thus far unknown whether in patients with a history of thromboembolism but without a defined clotting abnormality a heightened coagulation activation is detectable.

We investigated the value of prothrombin fragment Fl+2 (FI+2) as a predictor of recurrent venous thromboembolism. Furthermore, we compared the Fl+2 levels of thrombosis patients without a defined clotting defect to those of Factor V Leiden patients with a history of venous thrombosis and to those of healthy controls. 180 patients without a defined clotting abnormality and 73 patients with Factor V Leiden were prospectively followed after discontinuation of oral anticoagulants for venous thrombosis and Fl+2 was measured at regular intervals.

Recurrent venous thromboembolism occurred in 23 (9%) of the 253 patients. Before or at several time points after oral anticoagulants, no significant difference in Fl+2 levels was found in patients with and without recurrent thrombosis. Fl+2 levels at 3 weeks and prior to recurrence were not significantly different in both patient groups. Over a one-year observation period, Fl+2 levels of both patients with and without Factor V Leiden were higher than those of the controls. No difference in Fl+2 was seen between patients with and without Factor V Leiden.

We conclude that monitoring of Fl+2 is not suitable for identification of individuals at risk of recurrent venous thrombosis. Permanent hemostatic system activation is detectable both in patients with a defined abnormality of the clotting system and in patients in whom a particular defect has not (yet) been identified.

Pathophysiologie der Chemotherapie-assoziierten Thrombose

Epidemiologische Daten haben gezeigt, dass die meisten antineoplastischen Therapien das Risiko für venöse aber auch arterielle thromboembolische Ereignisse von Tumorpatienten deutlich verstärken. Diese Übersichtsarbeit gibt einen Überblick über das Thromboserisiko, welches mit der Gabe verschiedener klassischer Chemotherapeutika, Angiogenese-Inhibitoren und Immunmodulatoren verbunden ist, sowie deren potenziell zugrundeliegenden Mechanismen. Trotz zahlreicher Studien zeigt die vorliegende Arbeit, dass man von einem umfassenden Verständnis der Chemotherapie-assoziierten Thrombose weit entfernt ist.

The long-term recurrence risk of patients with unprovoked venous thromboembolism: an observational cohort study

Essentials Long-term recurrence risk of venous thromboembolism (VTE) is uncertain. We performed a prospective cohort study of 839 patients with first unprovoked VTE. VTE recurrence risk is high, particularly in men with proximal thrombosis or pulmonary embolism. Sex and VTE site determine the recurrence risk and should be considered for patient counseling.

SUMMARY

Background The long-term recurrence risk (ltRR) of venous thromboembolism (VTE) is uncertain. Objective To assess the ltRR of patients with first unprovoked VTE. Patients/methods Patients were classified into three categories: distal deep vein thrombosis (DVT), proximal DVT or pulmonary embolism (PE), that is, PE associated with DVT or isolated PE. Patients with major thrombophilia or antithrombotic therapy were excluded. The endpoint was recurrent symptomatic VTE. Results A total of 839 patients were followed for a median of 7.7 years. VTE recurred in 263 patients (31%). After 10 and 20 years, the cumulative ltRR was 32% (95% confidence interval [CI], 29-36) and 44% (95% CI, 38-49) with 3.9 (95% CI, 3.3-4.6) and 3.3 (95% CI, 2.7-4.0) events per 100 patient-years, respectively. The adjusted hazard ratio was 2.1 (95% CI, 1.4-3.2) and 2.1 (95% CI, 1.4-3.2) for patients with proximal DVT or PE compared with patients with distal DVT and was 2.1 (95% CI, 1.6-2.9) for men compared with women. At 10 years, 4.7 (95% CI, 3.8-5.8) events per 100 patient-years occurred in men with proximal DVT or PE, 2.4 (95% CI, 1.2-4.4) in men with distal DVT, 1.9 (95% CI, 1.2-2.8) in women with proximal DVT or PE and 0.9 (95% CI, 0.2-1.9) in women with distal DVT. Conclusion The ltRR of patients with first unprovoked VTE is high and dependent upon sex and VTE site.

Abstract P1-08-40: BRCA-1 promotor methylation and p53 mutation in triple-negative breast cancer patients refrectory to taxane-based neoadjuvant chemotherapy

Introduction

Triple-negative breast cancer (TNBC) without pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) is associated with high risk of disease recurrence. In ABCSG trials 14 and 24, concomitant epirubicin plus docetaxel (+/- capecitabine) was used as NAC regimen; patients (pts) without pCR routinely received another 4-8 cycles of adjuvant CMF.

Tumours harbouring BRCA-1 germline mutations are apparently less responsive to taxane-based chemotherapy, while sensitivity to DNA-damaging agents is retained. In sporadic TNBC, BRCA-1 promotor methylation is frequently observed; this may also result in an impaired activity of genetic repair mechanisms. Therefore, we investigated the effect of adjuvant CMF as salvage therapy in pts with or without BRCA-1 promotor methylation who did not achieve pCR to taxane-based (cyclophosphamide-free) NAC. Moreover, the predictive role of TP53 mutations was investigated in these tumours.

Methods

All pts with TNBC refractory to taxane-based NAC who received adjuvant CMF were included.

DNA was extracted from formalin-fixed paraffin-embedded tissue samples with the Qiagen DNA FFPE Tissue Kit® and purified. For determining BRCA1 promoter methylation status, DNA was bisulfite-treated; the TaqMan® assay was used in order to perform a quantitative methylation-specific PCR. DNA quantity was normalized using Actin-b.

For the investigation of TP53 mutations in exons 4-9, purified DNA was PCR amplified, sequenced by Sanger sequencing and results were analyzed with SeqScape® software version 2.7. Mutations were validated using the IARC p53 database.

Results

Twenty-four pts, median age 47 years, were available for this analysis. In 10/24 pts (41.7%), a BRCA-1 promotor methylation was detected; TP53 mutations were observed in 16/24 pts (66.7%). At a median follow-up of 27.5 months, 2/10 pts (20%) with BRCA-1 promotor metyhlation had a disease-free survival (DFS) event, as compared to 9/14 (64.3%) in the non-methylated group (p = 0.0472; Fisher's exact test). Kaplan Meier estimation of disease-free survival (DFS) in the non-methylated group was 16 months (95% CI 0.0-41.73) and was not reached in the methylated group (n.s.). TP53 mutation was neither associated with increased risk of disease recurrence nor with DFS. No correlation was observed between BRCA-1 promotor methylation and TP53 mutation; still, all methylated samples were exclusively affected be missense and nonsense mutations.

Conclusions

Adjuvant CMF is of limited activity in TNBC refractory to taxane-based NAC. Still, in breast cancer harbouring BRCA-1 promotor methylation, a significant decrease of DFS events was observed. TP53 mutation status on the other hand, was not associated with outcome; while no correlation was found between BRCA-1 promotor methylation and TP53 mutation status, we only observed missense and non-sense mutations in methylated samples.

In conclusion, tumours harbouring BRCA-1 promotor methylation are apparently sensitive to DNA damage caused by cyclophosphamide. Further clinical validation of this concept is warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-40.

Dabigatran in patients with atrial fibrillation: perioperative and periinterventional management

In any type of invasive surgery, the patient’s individual risk of thromboembolism has to be weighed against the risk of bleeding. Based on various everyday situations in clinical routine, the purpose of the present expert recommendations is to provide appropriate perioperative and periinterventional management for patients with atrial fibrillation undergoing long-term treatment with the thrombin inhibitor dabigatran. As we currently have no routine laboratory test to measure therapeutic levels of the substance or the risk of bleeding, general measures such as a standardized documentation of the patient’s history, a sufficient time interval between the last preoperative dose and the procedure, and careful control of local hemostasis should be given special attention.

[Pathophysiology of chemotherapy-associated thrombosis]

Epidemiological studies revealed that most antineoplastic agents and regimes enhance the risk of venous and arterial thromboembolic events in cancer patients. The purpose of this article is to review clinical and pathophysiological data related to chemotherapy-associated thromboembolism under special consideration of newer treatment strategies, such as angiogenesis inhibitors and immunmodulatory agents. Despite numerous clinical and experimental studies it has to be concluded that we are far from a comprehensive understanding of the pathogenesis of chemotherapy-associated thrombosis.

Comparison between idiopathic deep vein thrombosis of the upper and lower extremity regarding risk factors and recurrence

BACKGROUND

The pathogenesis and natural course of idiopathic upper extremity deep vein thrombosis (UEDVT) are unclear.

OBJECTIVE

To compare patients with UEDVT and with idiopathic lower extremity deep vein thrombosis (LEDVT) regarding risk factors and recurrence.

METHODS

We followed 50 patients with first idiopathic UEDVT and 841 patients with first idiopathic LEDVT for an average of 59 and 46 months, respectively. We excluded patients with natural inhibitor deficiency, lupus anticoagulant, cancer, pregnancy, isolated pulmonary embolism (PE), or long-term antithrombotic treatment. The endpoint was recurrent venous thromboembolism (VTE).

RESULTS

In comparison to LEDVT patients, UEDVT patients were younger (38 +/- 13 years vs. 49 +/- 16 years, P < 0.001), slimmer (body mass index: 24 +/- 4 vs. 27 +/- 5, P < 0.001), less frequently had a family history of VTE (18% vs. 31%, P = 0.06) or concomitant PE (8% vs. 31%, P =0.001), were less frequently carriers of factor V Leiden (12% vs. 30%, P = 0.009), and had lower thrombin generation marker levels (D-dimer, 283 +/- 361 ng mL(-1) vs. 456 +/- 446 ng mL(-1), P < 0.001; peak thrombin, 298 +/- 101 nm vs. 363 +/- 111 nm, P = 0.001). Recurrence occurred in two of 50 patients with UEDVT (4%) and in 129 of 841 patients with LEDVT (15%). After 5 years, the likelihood of recurrence was 2% [95% confidence interval (CI) 0-6] among UEDVT patients and 19% (95% CI 16-22; P = 0.02) among LEDVT patients. As compared to LEDVT patients, the adjusted risk of recurrence was 0.26 (95% CI 0.06-1.05; P = 0.059) in UEDVT patients.

CONCLUSION

The pathogenesis and natural course of the disease differ between patients with idiopathic UEDVT and LEDVT.

Chemotherapy-induced thrombin generation via procoagulant endothelial microparticles is independent of tissue factor activity

BACKGROUND

Cisplatin-based chemotherapy predisposes cancer patients to thromboembolic events.

OBJECTIVES

To investigate whether endothelial damage, via formation of procoagulant endothelial microparticles (EMPs), contributes to cisplatin-related hypercoagulability.

METHODS

Cell viability and caspase-3/7 activities were assessed in two endothelial cell (EC) lines [human umbilical vein ECs (HUVECs) and human pulmonary microvascular ECs (HMVEC-Ls)] after exposure to cisplatin (1, 2.5, 5, 10 and 20 microm) for up to 120 h. Counts and procoagulant activity of EMPs were measured by flow cytometry and a thrombin generation assay, respectively. Tissue factor (TF) antigen and TF-dependent procoagulant activity of EMP were determined by enzyme-linked immunosorbent assay and a novel functional assay.

RESULTS

By inducing apoptosis, cisplatin dose- and time-dependently decreased the viability of confluent HUVECs and HMVEC-Ls. Progression of EC death was accompanied by an increased release of EMPs (relative increase at 20 microm cisplatin for 48 h vs. control: HUVECs 6.5-fold, P < 0.001; HMVEC-Ls 18.4-fold, P < 0.001). EMPs were highly procoagulant (relative increase at 20 microm cisplatin for 48 h vs. control: HUVECs 2.5-fold, P < 0.001; HMVEC-Ls 5.9-fold, P < 0.001). EMP-driven thrombin generation, however, was not dependent on TF: TF expression and TF procoagulant activity levels on microparticles were only marginal and EMP-associated thrombin generation remained unchanged when the extrinsic pathway was blocked by omission of factor VIIa and/or incubation with an anti-human TF antibody. In contrast, blocking of phospholipids by annexin V markedly diminished EMP-associated procoagulant activity.

CONCLUSIONS

In vitro, cisplatin induced the release of EMPs that showed TF-independent procoagulant activity.

Prediction of recurrent venous thromboembolism by the activated partial thromboplastin time

BACKGROUND

Venous thromboembolism (VTE) is a multi-factorial disease. Extensive thrombophilia screening is costly and often inconclusive. Simple laboratory methods are required to predict the risk of recurrence.

OBJECTIVE

To assess if measurement of activated partial thromboplastin time (APTT) allows stratification of patients with VTE into high- and low-risk categories with regard to recurrence.

PATIENTS AND METHODS

We prospectively followed 918 patients with a first unprovoked VTE and studied the relationship between recurrence and an APTT after discontinuation of anticoagulation. APTT was expressed as a ratio of test to reference coagulation times. Study endpoint was symptomatic recurrent VTE.

RESULTS

Venous thromboembolism recurred in 101 (11%) patients. Patients without recurrence had a greater APTT ratio than those with recurrence (0.97 +/- 0.09 vs. 0.93 +/- 0.09, P = 0.001). After 4 years, probability of recurrent VTE was 8.5% (95% CI: 5.5-11.5%) among patients with a ratio equal to or > 0.95 and 15.6% (95% CI: 11.4-19.9%) among patients with a lower ratio (P = 0.005). Compared with patients with an APTT ratio < 0.95, the relative risk (RR) of recurrence among patients with a ratio equal to or > 0.95 was 0.56 (95% CI: 0.38-0.84, P = 0.005) before and 0.58 (95% CI: 0.39-0.87, P = 0.009) after adjustment for sex, age, factor V Leiden, and factor II G20210A.

CONCLUSIONS

Measurement of APTT allows stratification of patients with VTE into high- and low-risk categories with regard to recurrence.

The post-thrombotic syndrome: risk factors and impact on the course of thrombotic disease

BACKGROUND

The post-thrombotic syndrome (PTS) is a frequent complication of deep vein thrombosis (DVT). Patients with recurrent ipsilateral DVT have an increased risk of PTS; other risk factors are unknown.

OBJECTIVES

To establish risk factors of PTS and its impact on venous thrombotic disease.

PATIENTS

We prospectively followed 406 patients after a first symptomatic DVT for a median of 60 months. Patients with recurrent DVT, a natural inhibitor deficiency, the lupus anticoagulant, cancer, long-term anticoagulation, an observation time < 18 months and DVT-recurrence prior PTS-assessment were excluded. Study outcomes were occurrence of PTS and recurrent symptomatic DVT.

RESULTS

PTS was assessed after 44 +/- 23 months (mean +/- SD) using a clinical classification score. PTS developed in 176 of 406 patients (43.3%). Severe PTS was rare (1.4%). Proximal DVT was the strongest risk factor of PTS [odds ratio (OR) 2.1, 95% confidence interval (CI) 1.3-3.7]. Male gender (OR 1.6, 95% CI 1.0-2.8) and elevated D-dimer levels (OR 1.9, 95% CI 1.0-3.9) were weaker risk factors. Factor V Leiden, factor II G20210A or high factor VIII did not confer an increased risk of PTS. At 4 years, the cumulative probability of recurrence was 7.4% (95% CI 3.2-11.7) among patients with PTS when compared with 1.6% (95% CI 0-3.5; P < 0.02) among patients without PTS. The risk of recurrence was 2.6-fold (95% CI 1.2-5.9) increased when PTS was present.

CONCLUSIONS

Proximal DVT, male gender, and high D-dimer levels are independently associated with the development of PTS in patients with a first DVT. Patients with PTS have an increased risk of recurrent venous thromboembolism.

Diffuse large B-cell lymphomas with plasmablastic/plasmacytoid features are associated with TP53 deletions and poor clinical outcome

To define reproducible criteria for subgroups of diffuse large B-cell lymphomas (DLBCL), including lymphomas with plasmablastic/plasmacytoid features (PB/PC-Fs), we investigated 66 DLBCL; the samples were categorized as either centroblastic (CB), immunoblastic (IB) or PB/PC-F applying standardized morphologic criteria. Blinded specimens were reviewed by three independent pathologists. The final consensus classification included 44 CB (67%), seven IB (10%) and 15 PB/PC-F (23%). The interobserver agreement between two centers (Vienna, Würzburg) was 93.5%. Most PB/PC-F were CD20+, cIgM+, MUM-1+, CD138+/-, bcl-6-, corresponding to an activated B-cell phenotype. Immunoglobulin-V(H) gene mutation analysis was consistent with a germinal or postgerminal center-cell origin. By fluorescence in situ hybridization analysis, 11/13 (85%) PB/PC-F had a monoallelic TP53 deletion. The pretreatment characteristics of patients with PB/PC-F included a tendency for more B symptoms, extranodal disease and a higher IPI. Importantly, PB/PC-F were resistant to standard chemotherapy (complete remission rate 47%, relapse rate 71%) and even autologous stem-cell transplantation. The median overall survival (OS) (14 months, P<0.002) and disease-free survival (6 months, P=0.02) were significantly shorter compared to patients with CB and IB. The OS difference was pronounced within the low and low-intermediate IPI risk group (P<0.001). Our data indicate a strong association of plasmablastic/plasmacytoid morphology with TP53 deletions, poor response to chemotherapy and short survival.

Impact of cytogenetics on the prognosis of adults with de novo AML in first relapse

Karyotype is an important prognostic factor in patients with newly diagnosed acute myeloblastic leukaemia (AML). The prognostic value of cytogenetics on the outcome of patients with AML in relapse has not yet been well defined. We analysed the clinical outcome of 152 patients with de novo, chemotherapy-treated AML in first relapse according to the cytogenetic classification of the United Kingdom Medical Research Council. The rate of second complete remission (CR) (88, 64 and 36%) and the probability of survival at 3 years (43, 18 and 0%) were significantly different between the favourable, intermediate and adverse cytogenetic risk groups, respectively. Compared to the favourable group, the relative risk (RR) of death (multivariate analyses) was 2.6 (confidence interval (CI): 1.5-4.4, P<0.001) for the intermediate and 3.7 (CI: 1.7-7.9, P=0.001) for the adverse group. The prognostic value of the duration of first CR was confirmed (RR of death: 2.0 (CI: 1.0-4.0) for each additional year in first CR), whereas the FLT3 mutation obtained at diagnosis did not markedly influence the outcome of patients with AML in relapse. In conclusion, our results indicate that both karyotype and the duration of first CR are independent prognostic factors for patients with de novo AML in first relapse.

Marked increase in vascular endothelial growth factor concentrations during Escherichia coli endotoxin-induced acute inflammation in humans

BACKGROUND

Bacterial endotoxins can induce the synthesis and release of vascular endothelial growth factor (VEGF), which may alter vascular permeability and cause vascular leakage.

MATERIALS AND METHODS

The effect of acute systemic inflammation on VEGF concentration was measured in healthy males after an intravenous bolus infusion of Escherichia coli endotoxin (lipopolysaccharide, LPS, 20 IU kg-1) in a double-blind, placebo-controlled parallel group study. LPS administration was followed by an infusion of lepirudin (bolus 0.1 mg kg-1, continuous infusion of 0.1 mg kg-1 h-1, n = 12) or saline (n = 12).

RESULTS

Plasma VEGF increased from a mean of 15.1 pg mL-1 to 74.6 pg mL-1 5 h after LPS (P < 0.003). Body temperature, pulse rate, leukcytes, prothrombin fragment 1 + 2 (F1 + 2) and lactoferrin increased and platelets decreased after LPS (P < 0.05). The LPS-induced increase in VEGF was paralleled by the neutrophil cell degranulation marker lactoferrin but not by F1 + 2, and was not affected by lepirudin, which blunted F1 + 2 formation (P < 0.05).

CONCLUSIONS

Inflammation-induced activation of leukcytes rather than platelets plays a role in the marked increase in VEGF, which cannot be abrogated by antithrombotic therapy.

Efficacy and safety of splenectomy in adult chronic immune thrombocytopenia

For patients with adult chronic immune thrombocytopenia (ITP) splenectomy (SE) is a highly effective treatment, but there are still uncertainties regarding the long-term efficacy and safety. We evaluated the long-term efficacy and safety of SE in 48 consecutive adult patients with chronic ITP (26 women, 22 men) who underwent SE between 1990 and 2001 at the General Hospital in Vienna, Austria. All patients had no remission after steroid treatment and were steroid dependent. The median age at the time of SE was 44 years (range: 16-77 years). Of 48 patients, 37 achieved a complete remission (CR, platelet count >100 x 10(9)/l), 8 a partial remission (PR) (platelet count 30-100 x 10(9)/l), and 2 had no response (NR). The probability of the overall survival was 98% at a median postsplenectomy observation time of 3.5 years. Seven patients with CR and four patients with PR relapsed. There were no relapses after 1 year. The probability of continuous complete remission (CCR) at 10 years was 79%. The probability of having a platelet count of >100 x 10(9)/l or >30 x 10(9)/l was 61% and 67%, respectively, at 5 and 10 years after splenectomy. Of the 11 relapsed patients, 5 had a second CR ( n=3) or PR ( n=2). The postoperative platelet count was the best predictor for a long-term remission. All patients with postoperative platelet counts >250 x 10(9)/l remained in CR. Patients aged >45 years had a similar success rate as compared with younger patients. Three patients had infections (one pneumonia and two fever of unknown origin) requiring hospitalization, but none had overwhelming septicemia.

The risk of recurrent venous thromboembolism among patients with high factor IX levels

High factor IX (FIX) is a risk factor of deep vein thrombosis. The impact of high FIX on the risk of recurrent venous thrombosis is unknown. We prospectively followed 546 patients after anticoagulation for a first spontaneous venous thromboembolism. Patients with a natural coagulation inhibitor deficiency, lupus anticoagulant or cancer were excluded. At 3 years, the likelihood of recurrence was 23% among patients with high FIX (exceeding the 75th percentile) compared with 11% among patients with lower levels. Among patients with high FIX, the relative risk of recurrence was 2.2 (95% CI: 1.3-3.6) before and was 1.6 (95% CI: 1.0-2.8) after adjustment for age, gender, duration of anticoagulation, FV Leiden, FII G20210A, high FVIII and hyperhomocysteinemia. Compared with patients with low factor IX (< 138 IU dL(-1)) and low FVIII ( Collapse

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MESH Headings

• Adult
• Aged
• Anticoagulants/therapeutic use
• Factor IX/analysis
• Factor VIII/analysis
• Female
• Humans
• Incidence
• Male
• Middle Aged
• Prospective Studies
• Recurrence
• Risk Factors
• Thromboembolism/blood
• Venous Thrombosis/blood

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A comparative study on demographic, hematological, and cytogenetic findings and prognosis in acute myeloid leukemia with and without leukemia cutis

We studied the incidence of leukemia cutis (LC) in 381 consecutive patients with acute myeloid leukemia (AML) in a single institution and compared the demographic, hematological, and cytogenetic findings in AML patients with and without LC. We also examined the response to intensive chemotherapy, overall survival, and duration of remission in this patient population with regard to the presence of LC. The prevalence of LC was 3.7% in clinically diagnosed patients and 2.9% in biopsy-proven cases, respectively. Patients with and without LC did not differ with regard to age, sex, white blood cell counts, hemoglobin, fibrinogen, and platelet counts at diagnosis, but lactate dehydrogenase (LDH) was significantly higher in patients with LC. Various karyotype abnormalities were found, but in patients with LC numerical abnormalities of chromosome 8 were significantly more common ( P<0.0001). Patients with LC did not differ from patients without LC with regard to remission rate, but there was a trend towards shorter remission duration in patients with LC. We conclude that patients with LC have some features different from patients without this symptom. The increased frequency of numerical aberrations of chromosome 8 in patients with LC was the most interesting observation of our study. The pathophysiological significance of this finding remains to be determined.

Association of CD38 antigen expression with other prognostic parameters in early stages of chronic lymphocytic leukemia

The expression of the surface molecule CD38 on B cell chronic lymphocytic leukemia (B-CLL) cells has recently been described as a prognostic marker for patient survival. We have analyzed CD19/CD38 expression in 81 patients with predominantly early stages of B-CLL (69 Binet A, seven Binet B, five Binet C). Sixty-two patients (77%) had less than 30% CD38+/CD19+ cells, while 19 (23%) had > or = 30%. There was a significant association between Binet stages (A vs. B+C, p < 0.0001), Rai stages (0-II vs. III+IV, p < 0.001) and CD38 expression, confirming the published cut-off level of 30%. A particularly strong association between CD38 expression was found with soluble CD23 (sCD23) levels of > or = 2000 U/ml (p < 0.0001) and beta2-microglobulin (beta2 MG) serum levels of > or = 3 mg/l (p < 0.0001) indicating that CD38 is a marker of tumor mass as well as disease progression. A borderline association was found with lymphocyte doubling time (LDT) < 12 months (p = 0.05) due to low patient numbers, while there was no association with age, sex or immunoglobulin deficiency. Discordant results were obtained in a number of patients: 10 of 69 patients (14%) with Binet A had a CD38 > or = 30% while three of seven patients with Binet B had a CD38 < 30%. In these two subgroups CD38 and other prognostic factors gave discrepant results. Due to the early stage and short median observation time (12 months. range 1-24 months), calculations concerning patient survival were not performed. However, our data show a strong association between CD38 and other known prognostic factors. The results also suggest that this factor is not always reliable in Binet A patients.

Prognosis of patients with a second relapse of acute myeloid leukemia

Recurrence of the disease is the major problem in the treatment of acute myeloid leukemia (AML). The majority of patients who achieve a second remission will ultimately relapse. In this retrospective single-center study, we have analyzed the outcome of patients with a second relapse and tried to define the prognostic factors in intensively treated patients. Of 534 patients with AML, 62 had a second relapse. Thirty-three received further intensive chemotherapy (CT). Eighteen patients (55%) achieved a third complete remission (CR). The early death (ED) rate was only 9%. The overall survival (OS) of treated vs untreated patients was 6.9 vs 1.3 months, respectively (P = 0.01). The major selection criteria for a third CT were a favourable (t(15;17),t(8;21),inv(16)) or normal karyotype, long (>11 months) second CR (P < or = 0.005) and no previous bone marrow transplantation (BMT)(P < 0.01). Favorable or normal karyotype, second CR >11 months, as well as no previous BMT (P < 0.01) were associated with the achievement of a third CR. Favorable (P < 0.005) or normal karyotype (P < 0.01), as well as a second CR >11 months (P < 0.005) were associated with prolonged survival after CT. The median OS for patients receiving CT with favorable or normal cytogenetics, a second CR > 11 months, but no previous BMT was 26.5 months. Five patients with favorable or normal karyotype achieved a fourth or fifth remission. We conclude that intensive CT is associated with a survival benefit and good quality of life if patients are properly selected.

High plasma levels of factor VIII and the risk of recurrent venous thromboembolism

BACKGROUND

A high plasma level of factor VIII is a risk factor for venous thromboembolism. We evaluated the risk of a recurrence of thrombosis after an initial episode of spontaneous venous thromboembolism among patients with high plasma levels of factor VIII.

METHODS

We studied 360 patients for an average follow-up period of 30 months after a first episode of venous thromboembolism and discontinuation of oral anticoagulants. Patients who had recurrent or secondary venous thromboembolism, a congenital deficiency of an anticoagulant, the lupus anticoagulant, hyperhomocysteinemia, cancer, or a requirement for long-term treatment with antithrombotic drugs or who were pregnant were excluded. The end point was objectively documented, symptomatic recurrent venous thromboembolism.

RESULTS

Recurrent venous thromboembolism developed in 38 of the 360 patients (10.6 percent). Patients with recurrence had higher mean (+/-SD) plasma levels of factor VIII than those without recurrence (182+/-66 vs. 157+/-54 IU per deciliter, P=0.009). The relative risk of recurrent venous thrombosis was 1.08 (95 percent confidence interval, 1.04 to 1.12; P<0.001) for each increase of 10 IU per deciliter in the plasma level of factor VIII. Among patients with a factor VIII level above the 90th percentile of the values in the study population, the likelihood of recurrence at two years was 37 percent, as compared with a 5 percent likelihood among patients with lower levels (P<0.001). Among patients with plasma factor VIII levels above the 90th percentile, as compared with those with lower levels, the overall relative risk of recurrence was 6.7 (95 percent confidence interval, 3.0 to 14.8) after adjustment for age, sex, the presence or absence of factor V Leiden or the G20210A prothrombin mutation, and the duration of oral anticoagulation.

CONCLUSIONS

Patients with a high plasma level of factor VIII have an increased risk of recurrent venous thromboembolism.

Prolonged third remission in a patient with acute promyelocytic leukemia after consolidation chemotherapy with intermittent intermediate dose ara-C and maintenance with intermittent all-trans retinoic acid (ATRA)

The benefit of all-trans-retinoic acid (ATRA) in the front line therapy of acute promyelocytic leukemia (APL) is well established, but its role in postremission therapy and in the treatment of relapse is currently under investigation. Moreover, the impact of cytosine arabinoside (Ara-C) in the therapy of APL has been questioned in recent studies. We report a prolonged third molecular remission (MR) in a patient with hyperleukocytotic APL after induction with ATRA, consolidation chemotherapy (CT) with intermittent intermediate dose Ara-C and maintenance therapy with intermittent ATRA. While the first two remissions were relatively short (8 months and 11 months, resp.), the duration of the third continuous CR (49+ months) is more than twice as long as the length of the two previous remissions combined. In this case Ara-C followed by intermittent ATRA maintenance was a safe and effective therapy for relapsed disease. A third molecular remission of such duration and quality is unusual.

Treatment of hairy cell leukemia with cladribine (2-chlorodeoxyadenosine)

Hairy cell leukemia is a rare lymphoproliferative disorder resistant to conventional chemotherapeutic agents. Recently, the purine analogue cladribine (2-chlorodeoxyadenosine, 2-CdA) was introduced for the treatment of this disease. We report on 14 patients with hairy cell leukemia who were treated with 2-CdA at our department between 1993 and 1997. The patients received a single cycle of 2-CdA at a dose of 0.07 or 0.09 mg/kg/day by continuous infusion, over a seven-day period. Five patients were previously untreated, while the others had received prior treatment with interferon-alpha (seven patients), interferon-alpha and splenectomy (one patient) or interferon-alpha, splenectomy and pentostatin (one patient). Six patients achieved complete remission, three a good partial response and three partial remission. Two patients did not respond to treatment and one of them died from septicemia in aplasia. Relapse of the disease occurred in two patients. Side effects such as fever (WHO grade 2) and/or neutropenia (WHO grade 4) were noted in eight patients. Thus, 2-CdA is an effective treatment of hairy cell leukemia that can induce long lasting remissions in both, previously treated and untreated patients.

Chronic myelogenous leukemia in chronic phase for 16 years: ongoing hematological remission and late minor cytogenetic response under minimal interferon maintenance therapy

Philadelphia chromosome-positive chronic myelogenous leukemia was diagnosed in a now 37-year old woman 16 years ago. Induction therapy with hydroxyurea and busulphan led to hematological remission lasting for about 4 months without treatment. Then, intermittent busulphan over a 7 years' period, and subsequently, alpha-interferon was given, of which ever decreasing doses (currently 3.5 megaunits interferon-alpha-2c once every 14 days) have been required to keep leukocyte counts in the target range. Although no major cytogenetic response was achieved by maintenance therapy, the patient has now been in an ongoing chronic phase of disease for 16 years. This is a rare case of indolent chronic myelogenous leukemia, in which, for undefined reasons, the leukemic cells have not acquired the capacity to transform leading to disease acceleration, which usually is imminent after a few years.

Prospective evaluation of hemostatic system activation and thrombin potential in healthy pregnant women with and without factor V Leiden

Normal pregnancy is associated with alterations of the hemostatic system towards a hypercoagulable state and an increased risk of venous thromboembolism. The risk of venous thrombosis is higher in pregnant women with factor V Leiden (FVL) than in those with wildtype factor V. Routine laboratory assays are not useful to detect hypercoagulable conditions. A prospective and systematic evaluation of hemostatic system activation in women with and without FVL during an uncomplicated pregnancy employing more sensitive markers of hypercoagulability, such as prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT), D-Dimer, or the endogenous thrombin potential (ETP), an indicator of the plasma's potential to generate thrombin, has not been performed. We prospectively followed 113 pregnant women with (n = 11) and without (n = 102) FVL and measured F1+2. TAT, D-Dimer and the ETP at the 12th, 22nd and 34th gestational week as well as 3 months after delivery (baseline) in each subject. None of the women developed clinical signs of venous thromboembolism during pregnancy or postpartum. Pregnant women with and without FVL exhibited substantial activation of the coagulation and fibrinolytic system as indicated by a gradual increase of F1+2, TAT and D-Dimer throughout uncomplicated pregnancy up to levels similar to those found in acute thromboembolic events (p < 0.0001 by analysis of variance for each parameters). Levels of F1+2 and TAT were comparable between women with and without FVL, but levels of D-Dimer were significantly higher in women with FVL than in those without the mutation (p = 0.0005). The ETP remained unchanged in both women with and without FVL at all timepoints. Our data demonstrate a substantial coagulation and fibrinolytic system activation in healthy women with and without FVL during uncomplicated pregnancy. An elevated F1+2, TAT or D-Dimer level during pregnancy is not necessarily indicative for an acute thromboembolic event. The normal ETP in both women with and without FVL suggests that the capacity of the plasma to generate thrombin after in vitro activation of the clotting system is not affected by pregnancy. Higher levels of D-Dimer in women with FVL than in women with wildtype factor V at baseline as well as during pregnancy indicate increased fibrinolytic system activation in carriers of the mutation.

Massive disseminated intravascular coagulation and hyperfibrinolysis in alveolar rhabdomyosarcoma: case report and review of the literature

A 68-year-old woman presented with profuse hemorrhage and other signs suggesting an acute leukemia. Histologic and cytogenetic evaluation of her bone marrow revealed alveolar rhabdomyosarcoma as the underlying cause of massive disseminated intravascular coagulation and hyperfibrinolysis. A review of the literature reveals that coagulopathy appears to be a common feature of alveolar rhabdomyosarcoma.

Successful treatment with arsenic trioxide of a patient with ATRA-resistant relapse of acute promyelocytic leukemia

Arsenic trioxide has recently been introduced as a promising new agent to treat refractory acute promyelocytic leukemia (APL). In the present study, arsenic trioxide was given intravenously for 42 days to a 56-year-old female patient suffering from chemotherapy/ATRA-resistant APL, with 43% APL blasts in the bone marrow and elevated D-dimers. During the first days of arsenic trioxide treatment a rapid decrease in the D-dimers was seen (normal values reached until day 7), together with a slight decrease in peripheral blood leukocytes. This initial coagulation response was followed by a second phase of hematological response (starting on days 15-20) characterized by leukocytosis, occurrence of myeloid progenitor cells in the peripheral blood, and a decrease in bone marrow blasts (<1% on days 28 and 36). Finally, the patient entered complete hematological and cytogenetic remission, although the PML-RAR alpha fusion product was still detectable by PCR. These data confirm the therapeutic value of arsenic trioxide in relapsed/resistant APL.

Large amounts of vascular endothelial growth factor at the site of hemostatic plug formation in vivo

Vascular endothelial growth factor (VEGF) is important for the proliferation, differentiation, and survival of microvascular endothelial cells. It is a potent angiogenic factor and a specific endothelial cell mitogen that increases fenestration and extravasation of plasma macromolecules. Recently, large quantities of VEGF were detected in human megakaryocytes. Incubation of human platelets with thrombin in vitro resulted in the release of large amounts of VEGF. To investigate whether VEGF is released from platelets during coagulation activation in vivo, we measured in human subjects VEGF at the site of plug formation, ie, in blood emerging from a standardized injury made to determine bleeding time (shed blood). VEGF was also determined in the same volunteers after treatment with the specific thrombin inhibitor recombinant hirudin (r-hirudin). In a double-blind, randomized, crossover study, 17 healthy male volunteers (aged 20 to 35 years) were investigated. VEGF concentrations were measured in venous blood and in shed blood by the use of an immunoassay 10 minutes after intravenous administration of r-hirudin (0.35 mg/kg of body weight) or physiological saline. Prothrombin fragment f1.2 (f1.2) and beta-thromboglobulin (beta-TG) were determined as indicators of coagulation and platelet activation, respectively. Concentrations of VEGF, f1.2, and beta-TG in shed blood 4 minutes after injury were significantly higher than in venous blood (VEGF, 55.8+/-9.2 versus <20 pg/mL, P<0.001; f1.2, 71.3+/-10.4 versus 0.78+/-0.03 nmol/L, P<0. 001; beta-TG, 2290+/-170 versus 53.2+/-14.0 ng/mL, P<0.001). Administration of r-hirudin caused a >50% inhibition of the beta-TG and f1.2 levels in shed blood. In a similar manner, much lower amounts of VEGF were detectable at the site of plug formation after r-hirudin treatment (69.0+/-9.5 versus 37.8+/-2.6 pg/mL per minute; P=0.0015). Our data indicate that substantial quantities of VEGF are released from platelets during the interaction with the injured vessel wall in vivo. This finding may be relevant with respect to wound healing and tissue repair, tumor vascularization, or arterial thrombus formation.

Granulocyte colony-stimulating factor-supported combined immunosuppressive therapy (antilymphocyte globulin, cyclosporine, and methylprednisolone) in patients with aplastic anemia: tolerability, efficacy, and changes in the progenitor cell compartment

Neutropenic infections are the major cause of morbidity and mortality in the treatment of aplastic anemia (AA) with antilymphocyte globulin (ALG), cyclosporin A (CSA), and methylprednisolone (MP). Recent data suggest a beneficial effect of administering G-CSF as an adjunct to immunosuppression. We have treated 11 consecutive patients with AA using a combined immunosuppressive regimen including ALG, CSA, and MP plus G-CSF at a dose of 5 microg/kg/day until neutropoietic recovery. In addition to measuring routine hematological parameters we have performed serial determinations of reticulocyte counts and in vitro progenitor cell cultures before and after therapy in order to assess their predictive value for treatment response and to determine the impact of therapy on early hematopoiesis. One patient died on day 34 of neutropenic septicemia. At 1 year, 81% of patients showed response to treatment. The median time to ANC values >0.5 and >1.0 x 10(9)/l were 19 and 35 days, respectively. Reticulocyte counts started to recover after 6 weeks, and transfusion independence was observed on day 52 for red blood cell transfusions and on day 53 for platelet concentrates. All patients with detectable colony formation in peripheral blood achieved a complete hematological remission, as compared with only one of five patients without progenitor cell growth. Although normal ranges were rarely achieved, there was a small but definitive improvement in progenitor cell numbers as compared with baseline values in most patients. Our results confirm the good tolerability and high efficacy of this G-CSF-supported combined immunosuppressive therapy for AA. Detectable colony growth at diagnosis seems to predict a high chance for complete hematological response.

Clinical studies and thrombin generation in patients homozygous or heterozygous for the G20210A mutation in the prothrombin gene

A genetic variation in the prothrombin gene, the G-->A transition at nucleotide 20210, is a risk factor for venous thrombosis in heterozygotes and is associated with increased prothrombin activity. The homozygous phenotype and the extent of thrombin generation in heterozygous and homozygous subjects are unknown. We investigated a family that included 2 homozygous and 5 heterozygous carriers of the 20210 A allele. The homozygous propositus and his presumably heterozygous father suffered from deep-vein thrombosis. His presumably heterozygous mother and his homozygous sister had recurrent phlebitis at a young age. The remaining 5 affected family members are still asymptomatic. We studied thrombin generation in the family and in 22 unrelated carriers of the 20210 A allele by measuring (1) prothrombin fragment F1+2 (F1+2) as an index of ongoing thrombin generation and (2) the endogenous thrombin potential (ETP) as an index of the possible thrombin-forming capacity. Their F1+2 levels were not different from those of age-matched controls, and thus, ongoing hemostatic system activation was not detectable. A significantly increased ETP was found in the heterozygous carriers of the 20210A allele compared with the controls (527.8+/-114.9 versus 387+/-50.1 nmol/L x min, P<0.0001). In the 2 homozygotes, the ETP was almost twice (639 and 751 nmol/L x min, respectively) as high as in the controls. We conclude that homozygosity for the G20210A mutation in the prothrombin gene is associated with a severe, albeit more benign, thrombotic diathesis compared with homozygosity for deficiencies of antithrombin, protein C, or protein S. In carriers of the 20210 A allele, the pathomechanisms leading to thrombosis should be sought in the higher amounts of thrombin that may be formed once thrombin generation is triggered, rather than in ongoing thrombin generation in vivo.

Hypofibrinogenemia in non-M3 acute myeloid leukemia. Incidence, clinical and laboratory characteristics and prognosis

Among 379 patients with AML with FAB type M1, 2 and M4-7 diagnosed between 1978 and 1997 in our institution, 19 (5%) had hypofibrinogenemia (HF), ie a fibrinogen level <180 mg/dl. Compared to patients with normal fibrinogen (n = 360) patients with HF had significantly elevated markers of activation of coagulation (TAT, F1.2, FPA) and fibrinolysis (D-dimer, FDP) indicating that disseminated intravascular coagulation/hyperfibrinolysis was the cause of hypofibrinogenemia. Patients with HF had significantly longer prothrombin times, thrombin clotting and reptilase times. Factor X and VIII were significantly lower than in patients without HF. With the exception of M7, HF occurred in all FAB subtypes, but was most common in M5 (12.1%). Patients with HF did not differ from those with normal fibrinogen with regard to age, sex, leukocyte count and other hematological parameters. During induction chemotherapy fibrinogen normalized rapidly (median 5 days) and there was no increased incidence of early hemorrhagic death. The overall and disease-free survival was similar to that of patients without HF.

A novel immunoassay for the quantification of human tissue factor binding to activated factor VII

The binding of tissue factor to factors VII and VIIa (VII/VIIa) is the primary step for coagulation activation. Variants of human tissue factor leading to alterations in the binding to factor VII/VIIa have not been reported. We hypothesize that increased or decreased binding of tissue factor to factor VIIa might result in thrombosis and bleeding, respectively. The aim of this study was to establish an enzyme-linked immunosorbent assay to detect abnormalities in the binding of human tissue factor to recombinant factor VIIa (rVIIa). Tissue factor obtained from human monocytes was bound to rVIIa on microtiter wells in the presence of calcium. A murine antibody against human tissue factor and a biotinylated goat anti-mouse immunoglobuline were added. After incubation with streptavidin-horseradish peroxidase, colour development was measured using a chromogenic indicator system. Optimal assay conditions were obtained at tissue factor concentrations of 50-1500 pg/ml and rVIIa concentrations of 2.5 microg/ml. The binding of tissue factor to rVIIa was calcium-dependent and was inhibited by a monoclonal tissue factor antibody directed against the binding sites of tissue factor to rVIIa. The assay was evaluated in 23 healthy volunteers. Intra- and interassay variabilities were 3.9% and 10.2%, respectively. Among 22 subjects with unexplained bleeding and 47 patients with unexplained thrombosis, an individual with a decreased or increased binding of tissue factor to rVIIa could not yet be identified. In conclusion, this novel enzyme-linked immunosorbent assay can be used to detect and quantify an increased or a decreased binding of human tissue factor to rVIIa. Studies in patients indicate that, if such a defect exists, it is not a common cause of thrombosis or bleeding.

[Disseminated intravascular coagulation (DIG) with massive hyperfibrinolysis in metastatic uterine cancer. Observations on the effects on the coagulopathy of various treatments (a case report)]

We report on a 64-year-old patient with a recurrent endometrial carcinoma which was associated with disseminated intravascular coagulation (DIC) and excessive hyperfibrinolysis. The patient presented with severe bleeding due to hypofibrinogenemia. Fibrin degradation products were excessively elevated and there were also increased levels of activation markers of coagulation. Free plasmin was demonstrated in the circulation and alpha 2-antiplasmin was almost completely depleted. No increase in t-PA or u-PA level was demonstrated. Antifibrinolytic treatment led to a decrease of fibrin degradation products, but to an increase of activation markers of coagulation and was not associated with an increase of fibrinogen. Combination chemotherapy led to a rapid decrease of activation markers of coagulation and a sustained increase of fibrinogen. The beneficial effects on DIC/hyperfibrinolysis occurred despite the absence of any measurable effect of chemotherapy on the tumour. The patient finally died due to progression of the tumour, but without recurrence of the DIC/hyperfibrinolysis.

Levels of prothrombin fragment F1+2 in patients with hyperhomocysteinemia and a history of venous thromboembolism

Increased thrombin generation occurs in many individuals with inherited defects in the antithrombin or protein C anticoagulant pathways and is also seen in patients with thrombosis without a defined clotting abnormality. Hyperhomocysteinemia (H-HC) is an important risk factor of venous thromboembolism (VTE). We prospectively followed 48 patients with H-HC (median age 62 years, range 26-83; 18 males) and 183 patients (median age 50 years, range 18-85; 83 males) without H-HC for a period of up to one year. Prothrombin fragment F1+2 (F1+2) was determined in the patient's plasma as a measure of thrombin generation during and at several time points after discontinuation of secondary thromboprophylaxis with oral anticoagulants. While on anticoagulants, patients with H-HC had significantly higher F1+2 levels than patients without H-HC (mean 0.52 +/- 0.49 nmol/l, median 0.4, range 0.2-2.8, versus 0.36 +/- 0.2 nmol/l, median 0.3, range 0.1-2.1; p = 0.02). Three weeks and 3, 6, 9 and 12 months after discontinuation of oral anticoagulants, up to 20% of the patients with H-HC and 5 to 6% without H-HC had higher F1+2 levels than a corresponding age- and sex-matched control group. 16% of the patients with H-HC and 4% of the patients without H-HC had either F1+2 levels above the upper limit of normal controls at least at 2 occasions or (an) elevated F1+2 level(s) followed by recurrent VTE. No statistical significant difference in the F1+2 levels was seen between patients with and without H-HC. We conclude that a permanent hemostatic system activation is detectable in a proportion of patients with H-HC after discontinuation of oral anticoagulant therapy following VTE. Furthermore, secondary thromboprophylaxis with conventional doses of oral anticoagulants may not be sufficient to suppress hemostatic system activation in patients with H-HC.

Comparison of the effects of different low molecular weight heparins on the hemostatic system activation in vivo in man

In a double-blind, randomized, cross-over study the effects of single subcutaneous doses of 120 anti-Xa units/kg body wt. of three different low molecular weight heparin (LMWH) preparations were investigated in 15 healthy subjects by determination of thrombin-antithrombin III complex (TAT), prothrombin fragment 1.2 (f1.2), and beta-thromboglobin (beta-TG) in shed blood and in venous blood. Certoparin, dalteparin, and enoxaparin significantly inhibited coagulation activation marker formation in shed blood. The substantial inhibition of TAT and f1.2 formation was slightly more pronounced in response to certoparin. beta-TG was decreased following certoparin and enoxaparin, but not following dalteparin. However, no difference between groups was detectable. A small but consistent decrease of f1.2 formation in venous blood was noted for all LMWHs and dalteparin and enoxaparin, but not certoparin, inhibited TAT formation. Only a minor impact of the three LMWH preparations was noted on beta-TG plasma concentrations. Our data indicate that the studied LMWH preparations have a major impact on blood clotting in the activated state and inhibit in vivo the hemostatic system to a comparable extent.

Prothrombin fragment F1+2 is not predictive for recurrent venous thromboembolism

It would be important to estimate in advance the risk of recurrent thrombosis. Deficiencies of antithrombin, protein C or protein S, or resistance to activated protein C are associated with a biochemically detectable prethrombotic state. It is thus far unknown whether in patients with a history of thromboembolism but without a defined clotting abnormality a heightened coagulation activation is detectable. We investigated the value of prothrombin fragment F1+2 (F1+2) as a predictor of recurrent venous thromboembolism. Furthermore, we compared the F1+2 levels of thrombosis patients without a defined clotting defect to those of Factor V Leiden patients with a history of venous thrombosis and to those of healthy controls. 180 patients without a defined clotting abnormality and 73 patients with Factor V Leiden were prospectively followed after discontinuation of oral anticoagulants for venous thrombosis and F1+2 was measured at regular intervals. Recurrent venous thromboembolism occurred in 23 (9%) of the 253 patients. Before or at several time points after oral anticoagulants, no significant difference in F1+2 levels was found in patients with and without recurrent thrombosis. F1+2 levels at 3 weeks and prior to recurrence were not significantly different in both patient groups. Over a one-year observation period, F1+2 levels of both patients with and without Factor V Leiden were higher than those of the controls. No difference in F1+2 was seen between patients with and without Factor V Leiden. We conclude that monitoring of F1+2 is not suitable for identification of individuals at risk of recurrent venous thrombosis. Permanent hemostatic system activation is detectable both in patients with a defined abnormality of the clotting system and in patients in whom a particular defect has not (yet) been identified.

Inhibition rather than enhancement of hemostatic system activation during initiation of oral anticoagulant treatment

Coumarin-induced skin necrosis is believed to be due to a transient hypercoagulable state resulting from a more rapid decline of the protein C activity relative to that of coagulation factors (F) II, IX and X during initiation of oral anticoagulant therapy. We studied hemostatic system activation during early oral anticoagulant treatment with a technique that investigates coagulation activation in the microcirculation. We determined in 10 healthy volunteers the concentrations of prothrombin fragment F1 + 2 (f1.2) and thrombin-antithrombin complex (TAT) in blood emerging from an injury of the microvasculature (bleeding time incision) before and after initiation of both high-intensity and low-intensity coumarin therapy. In addition, f1.2, TAT, activated F VII (F VIIa) and the activities of F II, F VII, F X and protein C were measured in venous blood. A rapid decline of F VII and protein C was observed in venous blood with activities at 24 h of 7 +/- 1% and 43 +/- 2%, respectively, during the high-intensity regimen. A 20 to 30% reduction of f1.2 and TAT was seen in venous blood at 72 h with no major difference between the high- and the low-intensity regimen. F VIIa levels were substantially affected by anticoagulation with a > 90% reduction at 48 h during the high-intensity regimen. Following high-intensity coumarin, a > 50% decrease in the f1.2 and TAT levels was found in shed blood at 48 h suggesting substantial inhibition of thrombin generation during early oral anticoagulation. An increase in the f1.2 and TAT levels was seen neither in shed blood nor in venous blood. Our data do not support the concept of a transient imbalance between generation and inhibition of thrombin as the underlying pathomechanism of coumarin-induced skin nekrosis.

Studies on the neutralizing effects of protamine on unfractionated and low molecular weight heparin (Fragmin) at the site of activation of the coagulation system in man

In a double-blind, randomized, cross-over study the neutralizing action of protamine towards unfractionated heparin (UFH, 150 U/kg i.v.) and a low molecular weight heparin (LMWH, Fragmin, 100 anti-Xa U/kg i.v.) was investigated in 15 healthy subjects in vitro by measuring activated partial thromboplastin time (APTT), thrombin time (TT) and anti factor Xa activity (anti-Xa) in venous blood and in vivo by determination of prothrombin fragment 1.2 (f1.2) and thrombin-antithrombin III complexes (TAT) in venous blood and in shed blood. UFH and LMWH caused a prolongation of APTT and TT, an increase in anti-Xa and significantly inhibited f1.2 and TAT formation in shed blood, whereas only a minimal effect on TAT and f1.2 formation in venous blood was noted. Administration of 1 mg protamine/100 U UFH resulted in a near complete reversal of APTT, TT and anti-Xa, whereas lower doses (0.25 and 0.5 mg) were less effective. The effects of UFH on f1.2 and TAT generation in shed blood were partially (60-70%) neutralized only by the high dose (1.0 mg). Application of 1 mg protamine/100 anti-Xa U LMWH caused a near complete reversal of both APTT and TT but had only a weak effect on anti-Xa. In shed blood, the effect of LMWH on TAT and f1.2 formation was reversed by protamine only by 14% and 23% respectively. Our data do not support the concept that to reduce the incidence of protamine's potential clinical side effects, the administration of a lower dose of protamine than 1 mg protamine/100 U UFH is justified.(ABSTRACT TRUNCATED AT 250 WORDS)