Augmented Procoagulant Activity in Cancer Patients, Treated with Recombinant Interferon-γ in Addition to Recombinant Tumor Necrosis Factor-α and Melphalan

Several investigators have reported that interferon-gamma (IFN³) can alter tumor necrosis factor alpha induced effects in vitro. We assessed in vivo effects of recombinant interferon-gamma (rIFN³) on recombinant tumor necrosis factor-alpha (rTNF±) induced activation of systemic blood coagulation in a non-randomized study in 20 consecutive cancer patients. Eight patients were treated with rIFN³ prior to and during hyperthermic isolated limb perfusion with rTNF± and melphalan (IFN³ group). They were compared with twelve patients who did not additionally receive rIFN³ (non-IFN³ group)

Before start of perfusion, higher levels of TNFa, F1+2 and TAT levels were found in the IFN³ group. Fibrinogen and ATIII levels tended to be lower in this group. High TNF± levels, due to leakage during perfusion, were associated with activation of coagulation in all patients, that became obvious after the end of perfusion, when heparin treatment had been antagonized. Activation, measured by increased F1+2 and TAT levels, was significantly stronger in the IFN³y group. Monocytic TF remained low, possibly due to shedding of TF positive vesicles and/or sequestration of TF positive activated monocytes against the vessel wall. In both groups F1+2 and TAT levels declined 24 h after the perfusion, whereas monocytic TF increased to levels that were higher in the IFN³ group.

In conclusion, our data confirm a strong activation of coagulation induced by rTNF± in cancer patients. They suggest that rIFN³ may lead to a slight activation of coagulation and augments TNFa induced procoagulant activity. These effects may be due to rIFN³ induced sustained monocytic TF activity.

Subcutaneous Low-Molecular Weight Heparin or Oral Anticoagulants for the Prevention of Deep-Vein Thrombosis in Elective Hip and Knee Replacement?

Objective. To compare efficacy, safety, and feasibility of adjusted- dose oral anticoagulants (OAC) versus fixed-dose subcutaneous low molecular weight heparin (LMWH) for the prevention of deep venous thrombosis (DVT) in patients who have undergone elective hip or knee replacement.

Design. Multicentre, single blind randomised trial. OAC (acenocoumarol, target International Normalised Ratio, 2.0-3.0) and LMWH (nadroparine, 60 aXa IU/kg once daily) were started preoperatively and continued for 10 days. All outcome measures were adjudicated by an independent committee unaware of treatment allocation.

Subjects. 672 consecutive patients scheduled for elective hip or knee replacement surgery. All patients wore bilateral graduated compression stockings.

Main outcome measures. The endpoint for the assessment of efficacy was venography confirmed DVT or confirmed symptomatic pulmonary embolism. The endpoint for the assesment of safety was clinically important bleeding during study treatment or within 48 h of the end of treatment.

Results. Among the 517 patients with interpretable venograms, 391 had a hip replacement and 126 had a knee implant. DVT was demonstrated in 50 (20%) of 257 patients allocated to OAC and 43 (17%) of 260 patients allocated to nadroparine (p = 0.45), for an absolute difference in DVT incidence of 2.9% in favour of nadroparine (95% Cl, -3.7-9.5). Clinically important bleeding occurred in eight (2.3%) of the 342 oral anticoagulant treated patients and in five (1.5%) of the 330 nadroparine treated patients (p = 0.62), for an absolute difference in favour of nadroparine of 0.8% (95% Cl, -1.3-2.9).

Conclusion. Patients who undergo major orthopaedic operations have a high risk of venous thromboembolism. Once daily fixed-dose subcutaneous nadroparine is at least as efficacious and safe as daily adjusted OAC for prophylaxis against DVT after hip or knee implantation but is more simple to administer.

Effects of Hereditary and Acquired Risk Factors of Venous Thrombosis on a Thrombin Generation-Based APC Resistance Test

Several hereditary and acquired risk factors for venous thromboembolism (VTE) are associated with impaired down-regulation of thrombin formation via the protein C pathway. To identify individuals at risk, functional tests are needed that estimate the risk to develop venous thrombosis.

We determined the effects of hereditary and acquired risk factors of venous thrombosis on an APC resistance test that quantifies the influence of APC on the time integral of thrombin formation (the endogenous thrombin potential, ETP) initiated in plasma via the extrinsic coagulation pathway. APC sensitivity ratios (APCsr) were determined in plasma from carriers of factor VLeiden (n = 56) or prothrombin G20210A (n = 18), of individuals deficient in antithrombin (n = 9), protein C (n = 7) or protein S (n = 14) and of women exposed to acquired risk factors such as hormone replacement therapy (n = 49), oral contraceptive use (n = 126) or pregnancy (n = 35). We also analysed combinations of risk factors (n = 60).

The thrombin generation-based APC resistance test was sensitive for the factor VLeiden and prothrombin G20210A mutation, to protein S deficiency, hormone replacement therapy, oral contraceptive use and pregnancy. The assay was not influenced by antithrombin-or protein C deficiency. The presence of more than one risk factor of venous thrombosis resulted in more pronounced APC resistance. The APCsr of individuals with a single or combined risk factors of VTE correlated well with reported risk increases.

The thrombin generation-based APC resistance test identifies individuals at risk for venous thrombosis due to acquired risk factors and/or hereditary thrombophilic disorders that affect the protein C pathway.

Absolute annual incidences of first events of venous thromboembolism and arterial vascular events in individuals with elevated FVIII:c

Elevated levels of factor VIII:c (elevated FVIII:c) are associated with an increased risk for venous thromboembolism (VTE) and arterial vascular events, and are at least in part determined genetically. We prospectively followed 192 asymptomatic individuals with elevated FVIII:c (>150%) and 340 with normal levels for an average duration of 31 months (range 7 to 56 months) to investigate the risk of VTE and arterial vascular events. Participants were first degree relatives of consecutive patients with elevated FVIII:c and VTE or arterial vascular events before the age of 50 years. The incidences ofVTE were 1.25% (0.46–2.73) per year in the subjects with elevated FVIII:c, versus 0.23% (0.03–0.82) in those with normal levels (OR 5.5 [1.1–27.3]). The annual incidences of arterial vascular events were 1.04% (0.34–2.42) and 0.23% (0.03–0.82) in relatives with and without elevated levels of FVIII:c, respectively (OR: 4.5 [0.9–23.5]). After adjustment for age, smoking, known diabetes mellitus, hyperlipidemia, and hypertension, the odds ratio for any event was 3.7 (1.1–13.1). In conclusion, asymptomatic individuals with elevated FVIII:c levels and a positive family history of VTE or arterial vascular events before the age of 50 appear to have a high annual incidence of first VTE and arterial vascular events. Elevated FVIII:c may be a common risk factor for both clinical entities.

The risk of venous and arterial thrombosis in hyperhomocysteinaemia is low and mainly depends on concomitant thrombophilic defects

As homocysteine-lowering treatment has not reduced the risk of recurrent thrombosis in recent clinical trials, we hypothesized that mild hyperhomocysteinaemia is an epiphenomenon or associated with a low absolute risk of thrombosis. In this retrospective study, we enrolled 478 evaluable first-degree relatives of consecutive patients with venous thrombosis or premature atherosclerosis, and hyperhomocysteinemia. Absolute risks of thrombosis and effects of concomitant thrombophilic defects were compared. Relative risks were adjusted for clustering in families, age, sex, and atherosclerotic risk factors, where appropriate. Annual incidence of venous thrombosis was 0.16% (95% confidence interval [CI], 0.08–0.30) in hyperhomocysteinemic relatives versus 0.11% (CI, 0.05–0.20) in normohomocysteinemic relatives; adjusted relative risk 1.6 (CI, 0.6–4.5). Annual incidences of arterial thrombosis were 0.34% (CI, 0.21–0.52) and 0.24% (CI, 0.15–0.37) in hyperhomocysteinemic and normohomocysteinemic relatives, respectively; adjusted relative risk 1.5 (CI, 0.6–3.5). Concomitance of multiple thrombophilic risk factors increased the risk of venous thrombosis in hyperhomocysteinemic relatives 20 fold, but a comparable effect was demonstrated in normohomocysteinemic relatives. We conclude that hyperhomocysteinaemia is associated with a low absolute risk of venous and arterial thrombosis. Concomitant thrombophilic defects are probably main determinants on the risk of venous thrombosis, rather than hyperhomocysteinaemia itself.

Safety and efficacy of sucrose-formulated full-length recombinant factor VIII: Experience in the standard clinical setting

The safety of full-length sucrose-formulated recombinant factor VIII (rFVIII-FS; KOGENATE® FS) for up to 24 months of use was evaluated in a postmarketing observational study in Europe. Long-term safety and efficacy data were available for 212 patients with severe haemophilia A, including 13 previously untreated patients (PUPs) and 12 patients with 1–19 exposure days (EDs). Patients accumulated a mean (± SD) of 187 (121) EDs to rFVIII-FS and received a total of 39,627 infusions, mainly for prophylaxis and for the treatment of 4,283 spontaneous or trauma-related bleeds during an average observation time of 710 (136) days. Of these bleeding episodes, 85.4% were successfully treated with one or two infusions of rFVIII-FS. Haemostasis was also evaluated during 46 minor to major surgical pro- cedures, and the response to infusion was “excellent” or “good” in all cases. FVIII inhibitor formation was observed in six patients (two de novo; four persistent or recurrent). The de novo cases represent 8.0% (2 of 25) of patients who reported 0–19 previous EDs at study entry. Four of the five patients who reported possible drug-related adverse effects developed inhibitors. The results of this observational study demonstrate the efficacy and safety of rFVIII-FS during normal clinical use in the treatment of patients with severe haemophilia A. Furthermore, these findings are consistent with those of previous phase III clinical studies with rFVIII-FS, particularly with regard to its efficacy and low incidence of inhibitor formation.

High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin

Hereditary deficiencies of protein S, protein C and antithrombin are known risk factors for first venous thromboembolism. We assessed the absolute risk of recurrence, and the contribution of concomitant thrombophilic defects in a large cohort of families with these deficiencies. Annual incidence of recurrence was estimated in 130 deficient patients, with separate estimates for those with each of protein S, protein C, and antithrombin deficiency, and in eight non-deficient patients with prior venous thromboembolism. All patients were also tested for factor V Leiden, prothrombin G20210A, high levels of factors VIII, IX and XI, and hyperhomocysteinemia. There were 81 recurrent events among 130 deficient patients. Median follow-up was 4.6 years. Annual incidences (95% confidence interval) of recurrent venous thromboembolism were 8.4% (5.8–11.7) for protein S deficiency, 6.0% (3.9–8.7) for protein C deficiency, 10.0% (6.1–15.4) for antithrombin deficiency, and overall 7.7% (6.1–9.5). Relative risk of recurrence in patients with a spontaneous versus provoked first event was 1.5 (0.95–2.3). Cumulative recurrence rates at 1, 5 and 10 years were 15%, 38% and 53%. Relative risk of recurrence with concomitant defects was 1.4 (0.7–2.6) (1 defect) and 1.4 (0.8–2.7) (≥2 defects). Annual incidence was 1.0% (0.03–5.5) in eight non-deficient patients. Annual incidence of major bleeding in deficient patients on oral anticoagulant treatment was 0.5% (0.2–1.0). We conclude that patients with a hereditary protein S, protein C or antithrombin deficiency appear to have a high absolute risk of recurrence. This risk is increased after a first spontaneous event, and by concomitance of other thrombophilic defects.

Absolute risk of venous and arterial thromboembolism in thrombophilic families is not increased by high thrombin-activatable fibrinolysis inhibitor (TAFI) levels

High levels of thrombin-activatable fibrinolysis inhibitor (TAFI) are a supposed risk factor for thrombosis. However, results from previous studies are conflicting. We assessed the absolute risk of venous and arterial thromboembolism in subjects with high TAFI levels (>126 U/dl) versus subjects with normal levels, and the contribution of other concomitant thrombophilic defects. Relatives from four identical cohort studies in families with either deficiencies of antithrombin, protein C or protein S, prothrombin 20210A, high factor VIII levels, or hyperhomocysteinemia were pooled. Probands were excluded. Of 1,940 relatives, 187 had high TAFI levels. Annual incidences of venous thromboembolism were 0.23% in relatives with high TAFI levels versus 0.26% in relatives with normal TAFI levels (adjusted relative risk [RR] 0.8; 95% confidence interval [CI], 0.5–1.3). For arterial thrombosis these were 0.31% versus 0.23% (adjusted RR 1.4; 95% CI, 0.9–2.2). High levels of factor VIII, IX and XI were observed more frequently in relatives with high TAFI levels. Only high factor VIII levels were associated with an increased risk of venous and arterial thrombosis, independently of TAFI levels. None of these concomitant defects showed interaction with high TAFI levels. High TAFI levels were not associated with an increased risk of venous and arterial thromboembolism in thrombophilic families.

The Influence of NSAIDs on Coumarin Sensitivity in Patients with CYP2C9 Polymorphism After Total Hip Replacement Surgery

OBJECTIVE

To determine the influence of NSAIDs on the international normalized ratio (INR) in patients with cytochrome P450 (CYP)-2C9 enzyme variants starting acenocoumarol (an oral coumarin) therapy during the first 7 days after total hip replacement surgery.

METHODS

In this prospective study, an age-dependent protocol was used for the initiation of the acenocoumarol dose. Low-molecular-weight heparin was given for 5 days. The study included 100 patients undergoing total hip replacement surgery. After the inclusion of the last patient, polymerase chain reaction CYP2C9 mutation testing was performed for all patients. Drug-use evaluation of NSAIDs and other potential coumarin-drug interactions was also performed.

RESULTS

Eleven patients had an INR on 1 or more days >4.9. There were 52 patients who were using NSAIDs. Patients with a CYP2C9 mutation had a mean INR curve similar to patients without the mutation when NSAIDs were not coadministered. Within the group of patients heterozygous for a CYP2C9 mutation (n=30) only concomitant use of a NSAID resulted in an INR >4.9 (0% vs 38.9%, p<0.05).

CONCLUSION

In the group of patients with a CYP2C9 variant (*2 or *3 alleles), only concomitant use of a NSAID resulted in INRs >4.9. The cost effectiveness of CYP2C9 screening before elective surgery has yet to be determined.

Evaluation of 1025 fetal deaths: proposed diagnostic workup

OBJECTIVE

We sought to evaluate the contribution of different diagnostic tests for determining cause of fetal death. Our goal was to propose a workup guideline.

STUDY DESIGN

In a multicenter prospective cohort study from 2002 through 2008, for 1025 couples with fetal death ≥20 weeks' gestation, an extensive nonselective diagnostic workup was performed. A panel classified cause and determined contribution of diagnostics for allocating cause.

RESULTS

A Kleihauer-Betke, autopsy, placental examination, and cytogenetic analysis were abnormal in 11.9% (95% confidence interval [CI], 9.8-14.2), 51.5% (95% CI, 47.4-55.2), 89.2% (95% CI, 87.2-91.1), and 11.9% (95% CI, 8.7-15.7), respectively. The most valuable tests for determination of cause were placental examination (95.7%; 95% CI, 94.2-96.8), autopsy (72.6%; 95% CI, 69.2-75.9), and cytogenetic analysis (29.0%; 95% CI, 24.4-34.0).

CONCLUSION

Autopsy, placental examination, cytogenetic analysis, and testing for fetal maternal hemorrhage are basic tests for workup after fetal death. Based on the results of these tests or on specific clinical characteristics, further sequential testing is indicated.

Risk factors for cerebral venous thrombosis and deep venous thrombosis in patients aged between 15 and 50 years

Cerebral venous thrombosis (CVT) and deep vein thrombosis or pulmonary embolism (DVT/PE) are associated with many risk factors. It is unclear why CVT occurs less often than DVT/PE. Age dependent risk factors may play a role. The aim of our study was to compare risk factors in a uniform age group of CVT and DVT/PE patients aged between 15 and 50 years. Thrombophilic markers and clinical risk factors of 79 CVT patients and 173 DVT/PE patients aged 15-50 years were compared. Multivariable logistic regression analysis was performed to investigate if risk factors were independently associated with CVT or DVT/PE. Cerebral venous thrombosis patients were younger (median age 30 years vs. 42 years; p<0.001) and more often female (82% vs. 52%; p<0.001). There were no differences in thrombophilic markers. Cerebral venous thrombosis was less often associated with trauma, immobilisation or surgery than DVT/PE (6% vs. 21%; adjusted OR 0.29; 95%CI 0.10-0.82). In women, CVT was more frequently associated with oral contraceptive use, pregnancy or puerperium (82% vs. 53%; adjusted OR 2.34; 95%CI 1.03-5.32). This study demonstrated no differences in thrombophilic markers between CVT patients and DVT/PE patients aged between 15 and 50 years, while the frequency of some transient risk factors was different. Cerebral venous thrombosis was relatively more common in women and hormonal factors may predispose to CVT compared to DVT/PE, while trauma, immobilisation and surgery may be less important in the pathophysiology of CVT.

Risk of Recurrent Venous Thrombosis in Homozygous Carriers and Double Heterozygous Carriers of Factor V Leiden and Prothrombin G20210A

Background— Homozygous or double heterozygous factor V Leiden and/or prothrombin G20210A is a rare inherited thrombophilic trait. Whether individuals with this genetic background have an increased risk of recurrent venous thrombosis is uncertain.

Methods and Results— A case-control design within a large cohort of families with thrombophilia was chosen to calculate the risk of recurrent venous thrombosis in individuals with homozygosity or double heterozygosity of factor V Leiden and/or prothrombin G20210A. Cases were individuals with recurrent venous thrombosis, and controls were those with only 1 venous thrombosis. The cohort consisted of 788 individuals with venous thrombosis; 357 had factor V Leiden, 137 had prothrombin G20210A, 27 had factor V Leiden and/or prothrombin G20210A homozygosity, and 49 had double heterozygosity for both mutations. We identified 325 cases with recurrent venous thrombosis and 463 controls with only 1 venous thrombosis. Compared with noncarriers, crude odds ratio for recurrence was 1.2 (95% confidence interval, 0.9 to 1.6) for heterozygous carriers of factor V Leiden, 0.7 (95% confidence interval, 0.4 to 1.2) for prothrombin G20210A, 1.2 (95% confidence interval, 0.5 to 2.6) for homozygous carriers of factor V Leiden and/or prothrombin G20210A, and 1.0 (95% confidence interval, 0.6 to 1.9) for double heterozygotes of both mutations. Adjustments for age, sex, family status, first event type, and concomitance of natural anticoagulant deficiencies did not alter the risk estimates.

Conclusions— In this study, individuals with homozygous factor V Leiden and/or homozygous prothrombin G20210A or double heterozygous carriers of factor V Leiden and prothrombin G20210A did not have a high risk of recurrent venous thrombosis.

Microalbuminuria and risk of venous thromboembolism

CONTEXT

Microalbuminuria (albuminuria 30-300 mg per 24-hour urine collection) is a well-known risk marker for arterial thromboembolism. It is assumed that microalbuminuria reflects generalized endothelial dysfunction. Hence, microalbuminuria may also predispose for venous thromboembolism (VTE).

OBJECTIVE

To assess whether microalbuminuria is associated with VTE.

DESIGN, SETTING, AND PARTICIPANTS

Prevention of Renal and Vascular End-stage Disease (PREVEND) study, an ongoing community-based prospective cohort study initiated in 1997. All inhabitants of Groningen, The Netherlands, aged 28 through 75 years (n = 85,421) were sent a postal questionnaire and a vial to collect a first morning urine sample for measurement of urinary albumin concentration. Of those who responded (40,856), a cohort (8592 participants) including more participants with higher levels of urinary albumin concentration completed screening at an outpatient clinic. Screening data were collected on urinary albumin excretion (UAE) and risk factors for cardiovascular and renal disease.

MAIN OUTCOME MEASURE

Symptomatic and objectively verified VTE (ie, deep vein thrombosis, pulmonary embolism, or both) between study initiation and June 1, 2007.

RESULTS

Of 8574 evaluable participants (mean [SD] age, 49 [13] years; 50% men), 129 experienced VTE during a mean (SD) follow-up period of 8.6 (1.8) years, corresponding to overall annual incidence of 0.14% (95% confidence interval [CI], 0.11%-0.19%). Annual incidences were 0.12%, 0.20%, 0.40%, and 0.56% in participants with UAE of less than 15 (n = 6013), 15-29 (n = 1283), 30-300 (n = 1144), and greater than 300 (n = 134) mg per 24-hour urine collection, respectively (P for trend <.001). When adjusted for age, cancer, use of oral contraceptives, and atherosclerosis risk factors, hazard ratios associated with UAE levels of 15-29, 30-300, and greater than 300 mg/24 h were 1.40 (95% CI, 0.86-2.35), 2.20 (95% CI, 1.44-3.36), and 2.82 (95% CI, 1.21-6.61), respectively, compared with participants with UAE of less than 15 mg/24 h (global P = .001). Adjusted hazard ratio for microalbuminuria vs normoalbuminuria (UAE <30 mg/24 h) was 2.00 (95% CI, 1.34-2.98; P < .001). Microalbuminuria-related number needed to harm was 388 per year.

CONCLUSION

Microalbuminuria is independently associated with an increased risk for VTE.

High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin

Hereditary deficiencies of protein S, protein C and antithrombin are known risk factors for first venous thromboembolism. We assessed the absolute risk of recurrence, and the contribution of concomitant thrombophilic defects in a large cohort of families with these deficiencies. Annual incidence of recurrence was estimated in 130 deficient patients, with separate estimates for those with each of protein S, protein C, and antithrombin deficiency, and in eight non-deficient patients with prior venous thromboembolism. All patients were also tested for factor V Leiden, prothrombin G20210A, high levels of factors VIII, IX and XI, and hyperhomocysteinemia. There were 81 recurrent events among 130 deficient patients. Median follow-up was 4.6 years. Annual incidences (95% confidence interval) of recurrent venous thromboembolism were 8.4% (5.8-11.7) for protein S deficiency, 6.0% (3.9-8.7) for protein C deficiency, 10.0% (6.1-15.4) for antithrombin deficiency, and overall 7.7% (6.1-9.5). Relative risk of recurrence in patients with a spontaneous versus provoked first event was 1.5 (0.95-2.3). Cumulative recurrence rates at 1, 5 and 10 years were 15%, 38% and 53%. Relative risk of recurrence with concomitant defects was 1.4 (0.7-2.6) (1 defect) and 1.4 (0.8-2.7) (> or =2 defects). Annual incidence was 1.0% (0.03-5.5) in eight non-deficient patients. Annual incidence of major bleeding in deficient patients on oral anticoagulant treatment was 0.5% (0.2-1.0). We conclude that patients with a hereditary protein S, protein C or antithrombin deficiency appear to have a high absolute risk of recurrence. This risk is increased after a first spontaneous event, and by concomitance of other thrombophilic defects.

Relationship between Progression to AIDS and Thrombophilic Abnormalities in HIV Infection

Background: HIV-infected patients are at increased risk of venous and arterial thrombosis. We hypothesized that acquired thrombophilic abnormalities that could predispose to thrombosis are most pronounced in patients in advanced stages of HIV infection.

Methods: We included 109 consecutive HIV-infected patients in the study and tested them twice for currently known thrombophilic abnormalities at an interval of at least 3 months (median, 3 months; range, 3–12 months). Detailed information was collected about the date of diagnosis of HIV infection, HIV treatment, and previous episodes of venous and arterial thrombosis.

Results: After HIV infection was diagnosed, 16% of the patients experienced symptomatic thrombosis (venous, 10%; arterial, 6%). Repeated measurements established protein C deficiency in 9% of the patients, increased factor VIII concentrations in 41%, high fibrinogen concentrations in 22%, and free protein S deficiency in 60%. Median factor VIII concentrations were higher in patients with AIDS (CD4 cell counts &lt;2 × 108/L) than in patients with a non–AIDS-defining illness (2260 IU/L vs 1 490 IU/L; P &lt; 0.001), whereas median free protein S concentrations were lower (450 IU/L vs 580 IU/L; P &lt; 0.001). Developing AIDS was associated with increasing factor VIII concentrations and decreasing free protein S concentrations. Increasing factor VIII concentrations were correlated with increasing fibrinogen concentrations and decreasing free protein S concentrations.

Conclusions: Multiple acquired and persistent thrombophilic abnormalities are more frequently observed in HIV-infected patients than in the healthy population. The frequencies of these thrombophilic abnormalities increase with the progression to AIDS. These findings may contribute to the high prevalence of venous and arterial thrombosis in HIV-infected patients.

Possible contribution of cytomegalovirus infection to the high risk of (recurrent) venous thrombosis after renal transplantation

Renal transplant recipients are at an increased risk of venous thrombosis, which has been regarded as a postoperative complication, although it may persist afterwards. As numerous case reports have shown that active cytomegalovirus (CMV) infection can be found at time of onset of venous thrombosis, and is frequently found in renal transplant recipients, we hypothesized that one might be the result of the other. To calculate the risk of (recurrent) venous thrombosis in renal transplant recipients, and to see whether CMV infection influenced this risk, we retrospectively analysed 606 living consecutive renal transplant recipients. CMV status at time of transplantation and at time of enrolment was determined. Absolute risks of first venous thrombosis and recurrence were compared with CMV status, and were corrected for surgery related venous thrombosis, age, and anticoagulant treatment. Annual incidence of venous thrombosis was 0.88% (95% CI, 0.65-1.15) in all recipients and 0.59% (95% CI, 0.41-0.83) corrected for surgery related venous thrombosis. CMV positive and seroconverted recipients tended to have an increased risk of venous thrombosis compared to CMV negative recipients; corrected relative risks were 2.0 (95% CI, 0.9-5.2) and 1.7 (95% CI, 0.6-4.7), respectively. The cumulative 10-year recurrence rate of venous thrombosis in CMV seronegative, seroconverted, and seropositive recipients was 10%, 51% and 59%, respectively. We conclude that CMV infection tended to be associated with an increased risk of (recurrent) venous thrombosis. Prospective studies are warranted to establish this observation, which suggests that CMV infection influences the high risk of (recurrent) venous thrombosis in renal transplant recipients.

Mesenteric vein thrombosis associated with primary cytomegalovirus infection: a case report

In the past few years several studies have supported an interplay between cytomegalovirus infections and a prothrombotic state. We describe a case of primary cytomegalovirus infection in an immunocompetent adult that was complicated with mesenteric vein thrombosis. Transient protein C deficiency, lupus anticoagulant and activated protein C resistance were found, in combination with a heterozygous prothrombin G20210A mutation. We discuss the possible mechanisms of cytomegalovirus-related venous thrombosis.

High absolute risks and predictors of venous and arterial thromboembolic events in patients with nephrotic syndrome: results from a large retrospective cohort study

BACKGROUND

No data are available on the absolute risk of either venous thromboembolism (VTE) or arterial thromboembolism (ATE) in patients with nephrotic syndrome. Reported risks are based on multiple case reports and small studies with mostly short-term follow-up. We assessed the absolute risk of VTE and ATE in a large, single-center, retrospective cohort study and attempted to identify predictive factors in these patients.

METHODS AND RESULTS

A total of 298 consecutive patients with nephrotic syndrome (59% men; mean age, 42+/-18 years) were enrolled. Mean follow-up was 10+/-9 years. Nephrotic syndrome was defined by proteinuria > or =3.5 g/d, and patients were classified according to underlying histological lesions accounting for nephrotic syndrome. Objectively verified symptomatic thromboembolic events were the primary study outcome. Annual incidences of VTE and ATE were 1.02% (95% confidence interval, 0.68 to 1.46) and 1.48% (95% confidence interval, 1.07 to 1.99), respectively. Over the first 6 months of follow-up, these rates were 9.85% and 5.52%, respectively. Proteinuria and serum albumin levels tended to be related to VTE; however, only the predictive value of the ratio of proteinuria to serum albumin was significant (hazard ratio, 5.6; 95% confidence interval, 1.2 to 26.2; P=0.03). In contrast, neither the degree of proteinuria nor serum albumin levels were related to ATE. Sex, age, hypertension, diabetes, smoking, prior ATE, and estimated glomerular filtration rate predicted ATE (P< or =0.02).

CONCLUSIONS

This study verifies high absolute risks of symptomatic VTE and ATE that were remarkably elevated within the first 6 months. Whereas the ratio of proteinuria to serum albumin predicted VTE, estimated glomerular filtration rate and multiple classic risk factors for atherosclerosis were predictors of ATE.

Absolute annual incidences of first events of venous thromboembolism and arterial vascular events in individuals with elevated FVIII:c. A prospective family cohort study

Elevated levels of factor VIII:c (elevated FVIII:c) are associated with an increased risk for venous thromboembolism (VTE) and arterial vascular events, and are at least in part determined genetically. We prospectively followed 192 asymptomatic individuals with elevated FVIII:c (>150%) and 340 with normal levels for an average duration of 31 months (range 7 to 56 months) to investigate the risk of VTE and arterial vascular events. Participants were first degree relatives of consecutive patients with elevated FVIII:c and VTE or arterial vascular events before the age of 50 years. The incidences of VTE were 1.25% (0.46-2.73) per year in the subjects with elevated FVIII:c, versus 0.23% (0.03-0.82) in those with normal levels (OR 5.5 [1.1-27.3]). The annual incidences of arterial vascular events were 1.04% (0.34-2.42) and 0.23% (0.03-0.82) in relatives with and without elevated levels of FVIII:c, respectively (OR: 4.5 [0.9-23.5]). After adjustment for age, smoking, known diabetes mellitus, hyperlipidemia, and hypertension, the odds ratio for any event was 3.7 (1.1-13.1). In conclusion, asymptomatic individuals with elevated FVIII:c levels and a positive family history of VTE or arterial vascular events before the age of 50 appear to have a high annual incidence of first VTE and arterial vascular events. Elevated FVIII:c may be a common risk factor for both clinical entities.

High risk of pregnancy-related venous thromboembolism in women with multiple thrombophilic defects

Pregnancy is associated with an increased risk of venous thromboembolism, which probably varies according to the presence of single or multiple thrombophilic defects. This retrospective family cohort study assessed the risk of venous thromboembolism during pregnancy and puerperium, and the contribution of concomitant thrombophilic defects in families with hereditary antithrombin, protein C or protein S deficiencies. Probands were excluded. Of 222 female relatives, 101 were deficient and 121 non-deficient. Annual incidences of venous thromboembolism were 1.76% in deficient women versus 0.19% in non-deficient women [adjusted relative risk (RR) 11.9; 95% confidence interval (CI), 3.9-36.2]. Other single and multiple thrombophilic defects increased the risk in deficient women from 1.55% to 2.14% and 2.92%, and in non-deficient women from 0.16% to 0.09% and 0.54% respectively. Deficient women were at lower risk (1.37%; 0.80-2.19) than deficient women that had never been pregnant (2.96%; 1.53-5.18); RR 0.5 (0.2-0.99). This difference was due to the predominance of events related to oral contraceptives in deficient women that had never been pregnant (75%), while 71% of events in deficient women that had had at least one pregnancy were pregnancy-related. In conclusion, women with hereditary deficiencies of antithrombin, protein C or protein S are at high risk of pregnancy-related venous thromboembolism. This risk is increased by multiple additional thrombophilic defects.

The risk of venous and arterial thrombosis in hyperhomocysteinaemia is low and mainly depends on concomitant thrombophilic defects

As homocysteine-lowering treatment has not reduced the risk of recurrent thrombosis in recent clinical trials, we hypothesized that mild hyperhomocysteinaemia is an epiphenomenon or associated with a low absolute risk of thrombosis. In this retrospective study, we enrolled 478 evaluable first-degree relatives of consecutive patients with venous thrombosis or premature atherosclerosis, and hyperhomocysteinemia. Absolute risks of thrombosis and effects of concomitant thrombophilic defects were compared. Relative risks were adjusted for clustering in families, age, sex, and atherosclerotic risk factors, where appropriate. Annual incidence of venous thrombosis was 0.16% (95% confidence interval [CI], 0.08-0.30) in hyperhomocysteinemic relatives versus 0.11% (CI, 0.05-0.20) in normohomocysteinemic relatives; adjusted relative risk 1.6 (CI, 0.6-4.5). Annual incidences of arterial thrombosis were 0.34% (CI, 0.21-0.52) and 0.24% (CI, 0.15-0.37) in hyperhomocysteinemic and normohomocysteinemic relatives, respectively; adjusted relative risk 1.5 (CI, 0.6-3.5). Concomitance of multiple thrombophilic risk factors increased the risk of venous thrombosis in hyperhomocysteinemic relatives 20 fold, but a comparable effect was demonstrated in normohomocysteinemic relatives. We conclude that hyperhomocysteinaemia is associated with a low absolute risk of venous and arterial thrombosis. Concomitant thrombophilic defects are probably main determinants on the risk of venous thrombosis, rather than hyperhomocysteinaemia itself.

Oral contraceptives and the absolute risk of venous thromboembolism in women with single or multiple thrombophilic defects: results from a retrospective family cohort study

BACKGROUND

The risk of venous thromboembolism (VTE) in women taking combined oral contraceptives (COCs) is attributed to changes in coagulation and fibrinolysis. Their impact may be greater in women with preexistent thrombophilic defects.

METHODS

We assessed the effects of COCs on absolute VTE risk in women with single or multiple thrombophilic defects in a retrospective family cohort study. Female relatives of probands with VTE and hereditary deficiencies of protein S, protein C, or antithrombin were tested for known thrombophilic defects, including the index deficiency. Absolute incidences of VTE were compared in deficient vs nondeficient women, in deficient and nondeficient women who ever or never used COCs, and in deficient and nondeficient women with 0, 1, or more than 1 other thrombophilic defect during exposure to COCs.

RESULTS

Of 222 women, 135 (61%) ever used COCs. Overall, annual incidences of VTE were 1.64% and 0.18% in deficient and nondeficient women, respectively; the adjusted relative risk was 11.9 (95% confidence interval, 3.9-36.2). The risk was comparable in deficient ever and never users (1.73% vs 1.54%). Annual incidences during actual COC use were 4.62% in deficient women and 0.48% in nondeficient women; the relative risk was 9.7 (95% confidence interval, 3.0-42.4). The incidence increased by concomitant thrombophilic defects, from 3.49% to 12.00% in deficient women and from 0% to 3.13% in nondeficient women.

CONCLUSIONS

Women with hereditary deficiencies of protein S, protein C, or antithrombin are at high risk of VTE during use of COCs, particularly when other thrombophilic defects are present. They have VTE at a younger age, but the overall risk is not increased by COCs.

Reduction of high fetal loss rate by anticoagulant treatment during pregnancy in antithrombin, protein C or protein S deficient women

Hereditary thrombophilia is associated with an increased risk of fetal loss. Assuming that fetal loss is due to placental thrombosis, anticoagulant treatment might improve pregnancy outcome. In an observational family cohort study, we prospectively assessed the effects of anticoagulant drugs on fetal loss rates in women with hereditary deficiencies of antithrombin, protein C or protein S. The cohort contained 376 women (50 probands and 326 deficient or non-deficient relatives). Probands were consecutive deficient patients with venous tromboembolism. Thromboprophylaxis during pregnancy was recommended in deficient women, irrespective of prior venous thromboembolism, and in non-deficient women with prior venous thromboembolism. Outcome of first pregnancy was analysed in 55 eligible women. Of 37 deficient women, 26 (70%) received thromboprophylaxis during pregnancy, compared with three of 18 (17%) non-deficient women. Fetal loss rates were 0% in deficient women with thromboprophylaxis versus 45% in deficient women without (P = 0.001) and 7% in non-deficient women without thromboprophylaxis (P = 0.37). The adjusted relative risk of fetal loss in women who received thromboprophylaxis versus women who did not was 0.07 (95% confidence interval 0.001-0.7; P = 0.02). Our data suggest that anticoagulant treatment during pregnancy reduces the high fetal loss rate in women with hereditary deficiencies of antithrombin, protein C or protein S.

Contribution of multiple thrombophilic and transient risk factors in the development of cerebral venous thrombosis

INTRODUCTION

Cerebral venous thrombosis (CVT), deep vein thrombosis (DVT) and/or pulmonary embolism (PE) have been associated with thrombophilic defects. However, in contrast to DVT or PE, CVT is a rare disease. We performed a study to identify differences in thrombotic risk profile, predisposing to CVT rather than DVT or PE, particularly the contribution of oral contraception and 11 thrombophilic defects.

MATERIALS AND METHODS

A single center case-control study (63 CVT cases and 209 controls with DVT or PE) was performed.

RESULTS

Of CVT patients, 11% had experienced prior DVT or PE, and none had recurrent CVT at 5 years follow-up. CVT was more frequently observed in females (79% versus 51%, P<0.001). It was more often secondary (75% versus 50%, P<0.001), mainly due to the difference in age between both groups. At presentation of CVT and DVT/PE, oral contraceptives were used by 78% and 74% of non-pregnant fertile women (P=0.8), respectively. Any thrombophilic defect was demonstrated in 88% of CVT and 75% of DVT/PE patients (P=0.22), sex and age matched. Individual and two or more defects were equally distributed among both groups.

CONCLUSIONS

We conclude that a majority of CVT and DVT or PE patients show single or multiple thrombophilic defects. At presentation, oral contraceptive intake was observed more frequently in CVT patients. However, no differences were observed in thrombotic risk profile between both groups of comparable age. Hence, additional unknown risk factors should be considered to explain the different sites of thrombosis in these patients.

The pathogenesis of venous thromboembolism: evidence for multiple interrelated causes

BACKGROUND

Venous thromboembolism (VTE) is thought to result from interactions between multiple genetic and environmental risk factors.

OBJECTIVE

To assess the contribution of multiple thrombophilic defects and exogenous risk factors to the absolute risk for VTE.

DESIGN

Retrospective family cohort study.

SETTING

Single university hospital.

PARTICIPANTS

468 relatives of 91 probands with a symptomatic hereditary deficiency of protein S, protein C, or antithrombin.

MEASUREMENTS

All relatives were tested for 10 thrombophilic deficiencies and defects in addition to the index deficiency and were assessed for exogenous risk factors (surgery, trauma, immobilization, use of oral contraceptives, and pregnancy). The authors compared annual incidences and relative risks for VTE in deficient and nondeficient relatives.

RESULTS

Annual incidences of VTE in relatives with 0, 1, and 2 or more additional thrombophilic deficiencies or defects were 1.16 (95% CI, 0.60 to 2.03), 1.75 (CI, 1.17 to 2.53), and 2.64 (CI, 1.67 to 3.96) per 100 person-years, respectively, compared with 0.06 (CI, 0.002 to 0.33) per 100 person-years in nondeficient relatives without additional deficiencies or defects. Adjusted relative risks were 16.3 (CI, 2.0 to 131.0), 50.3 (6.5 to 389.7), and 102.8 (12.5 to 843.4). Of deficient relatives, 38% with no additional defect, 57% with 1 additional defect, and 81% with 2 or more additional defects had VTE at age 65 years compared with 5% of nondeficient relatives (P < 0.001). In deficient relatives with additional deficiencies or defects, exogenous risk factors increased the risk for VTE from 1.20% to 2.51% per year (relative risk, 2.1 [CI, 1.1 to 4.2]).

LIMITATIONS

This was a retrospective study without the ability to distinguish interactions between specific thrombophilic deficiencies and defects.

CONCLUSION

Additional thrombophilic defects and exogenous risk factors increase the risk for VTE in persons with hereditary deficiencies of protein S, protein C, or antithrombin and provide evidence that multiple genetic and environmental risk factors contribute to VTE.

Identification of a novel PROS1 c.1113T-->GG frameshift mutation in a family with mixed type I/type III protein S deficiency

We report a family with type I and type III protein S (PS) deficiency, which showed to be phenotypic variants of the same genetic disease. Direct sequencing analysis of the PROS1 gene was performed to establish the genotype. The ratio of protein C antigen and total PS antigen levels (protein C/S ratio) was used to classify subjects at risk of venous thromboembolism. All PS deficient subjects had increased protein C/S ratios as well as a novel PROS1 c.1113T-->GG frameshift mutation.

A prospective cohort study on the absolute incidence of venous thromboembolism and arterial cardiovascular disease in asymptomatic carriers of the prothrombin 20210A mutation

The prothrombin 20210A mutation has been associated with an increased risk for venous thromboembolism (VTE) and arterial cardiovascular disease. The risks for asymptomatic carriers of this mutation have thus far been studied only in case-control and retrospective cohort studies. Here we present the results of the first prospective observational study in asymptomatic first-degree family members of patients with either VTE or premature atherosclerosis and the prothrombin 20210A mutation. We included 464 individuals (236 carriers) with a total follow-up duration of 1816 years (943 years for the carriers). The annual incidence of a first VTE was 0.37% (95% CI, 0.08-1.08) for carriers and 0.12% (95% CI, 0.00-0.69) for noncarriers (HR, 3.1; 95% CI, 0.3-29.6). The annual incidence of a first arterial cardiovascular event was 0.56% (95% CI, 0.18-1.31) for carriers and 0.73% (95% CI, 0.27-1.58) for noncarriers (adjusted HR, 0.7; 95% CI, 0.2-2.5). We conclude that the absolute incidence of a first VTE or arterial cardiovascular event is low; therefore, the clinical implications of carriership of the prothrombin 20210A mutation are limited, and routinely testing all first-degree relatives of probands with this mutation does not appear to be justified.

Acute chemotherapy-induced cardiovascular changes in patients with testicular cancer

PURPOSE

After cisplatin- and bleomycin-containing chemotherapy for testicular cancer, part of the patient population will develop acute or long-term cardiovascular toxicity. It is largely unknown whether standard tests can be used to assess chemotherapy-induced cardiovascular changes.

PATIENTS AND METHODS

In 65 testicular cancer patients (median age, 27 years; range, 18 to 48 years), we measured the following cardiovascular parameters before and within 10 weeks after completion of cisplatin-based chemotherapy: platelet numbers, plasma levels of hemostatic and fibrinolytic factors, 24-hour ambulatory blood pressure, baroreflex sensitivity, intima-media thickness of the common carotid artery, and flow-mediated vasodilation of the brachial artery.

RESULTS

Compared with prechemotherapy values, the intima-media thickness of the carotid artery and plasma von Willebrand factor levels increased significantly after treatment. Platelet numbers and plasma levels of other hemostatic and fibrinolytic factors did not appear to change significantly. Blood pressure decreased significantly, but flow-mediated vasodilation and baroreflex sensitivity did not change.

CONCLUSION

In testicular cancer patients treated with cisplatin-based chemotherapy, we found an increase in plasma von Willebrand factor levels and in the intima-media thickness of the carotid artery. These changes may indicate chemotherapy-induced vascular damage and be of prognostic significance for the development of cardiovascular complications in the long term.

Safety and efficacy of a single bolus administration of recombinant factor VIIa in liver transplantation due to chronic liver disease

Orthotopic liver transplantation (OLT) can be associated with excessive blood loss. As a result, there may be increased risk of adverse outcomes. Activated recombinant factor VII (rFVIIa) has demonstrated the ability to improve hemostasis in a variety of disorders; however, there has been a limited amount of research into its use in OLT. The purpose of this dose-finding study was to examine the efficacy and safety of rFVIIa in the reduction of bleeding in patients undergoing OLT. In this double-blind trial, patients with end-stage liver disease scheduled for OLT were randomized to 1 of 4 parallel study groups. They received a single intravenous bolus of rFVIIa (20, 40, or 80 microg/kg) or placebo prior to surgery. The primary assessment endpoint was the total number of red blood cell (RBC) units transfused perioperatively. Safety was evaluated by adverse events reported. Eighty-three comparable patients were randomized to receive study product, with 82 ultimately undergoing OLT. There were no significant differences in required RBC units between the placebo and rFVIIa study groups. The number of adverse events was comparable between study groups. In conclusion, rFVIIa has a good safety profile in patients undergoing OLT. However, the doses studied did not have any effect on the number of RBC transfusions required.

Treatment of venous thromboembolism with vitamin K antagonists: patients' health state valuations and treatment preferences

Determining the optimal duration of vitamin K antagonist (VKA) therapy for patients with venous thromboembolism (VTE) requires a weighting of the benefits and risks of treatment. The objectives of our study were to investigate patient variability in health state valuations associated with VKA therapy and treatment preferences, and to investigate the extent to which valuations and treatment preferences are associated with prior experience with these health states and other patient characteristics. Valuations of outcomes after VTE scaled from 0 (tantamount to death) to 1 (tantamount to perfect health) were elicited from 53 patients who had experienced VTE, 23 patients who had experienced major bleeding during treatment, and 48 patients with the post-thrombotic syndrome. In addition, patients' treatment preferences were evaluated using treatment trade-off questions. Median health state valuations ranged from 0.33 for 'non-fatal haemorrhagic stroke' to 0.96 for 'no VKA treatment'. Variability between patients was substantial. Patients' treatment preferences also varied: 25% of patients chose cessation of treatment, regardless of the probability of recurrent VTE presented, whereas 23% of patients were never willing to choose cessation of treatment. Differences in valuations and treatment preferences were not associated with type of event experienced. Due to the substantial and unpredictable variability in valuations and treatment preferences, recommendations regarding treatment duration should be tailored to patients' specific values and concerns.

Unselected women with elevated levels of factor VIII:C or homocysteine are not at increased risk for obstetric complications

Acquired and hereditary thrombophilias are associated with obstetric complications such as (pre-)eclampsia, HELLP syndrome and fetal loss. Our objective was to assess the risk of obstetric complications in women with elevated levels of FVIII:C or hyperhomocysteinemia, as compared with their relatives who had normal FVIII:C or homocysteine levels. From a large family study of patients with venous thromboembolism or premature atherosclerosis and elevated levels of FVIII:C or hyperhomocysteinemia (propositi), the obstetric histories of female first degree relatives, who had been pregnant at least once, were studied. Levels of FVIII:C and homocysteine (both fasting and post-methionine loading) were determined. The number of obstetric complications was calculated and compared in women with normal and elevated levels of FVIII:C, and normal and elevated levels of homocysteine. Women with elevated levels of FVIII:C had a 15.4% risk for toxicosis, preeclampsia, or HELLP syndrome and a 23.9% for fetal loss. This was not statistically different from women with normal levels of FVIII:C. Women with hyperhomocysteinemia tended to have a lower risk for toxicosis, pre-eclampsia, or HELLP syndrome (8.0%, RR 0.6, 95% CI 0.2-1.7) and fetal loss (22.0%, RR 0.8, 95% CI 0.5-1.5) as compared to relatives with normal levels, although these differences did not reach statistical significance. If the analysis was limited to comparing extremes, the results did not materially differ. Unselected women with elevated plasma levels of FVIII:C or hyperhomocysteinemia are not at increased risk for obstetric complications as compared to their relatives with normal levels.

Protein S type III deficiency is no risk factor for venous and arterial thromboembolism in 168 thrombophilic families: a retrospective study

Free protein S rather than total protein S levels are currently measured to detect inherited protein S deficiency. Because type III (free protein S) deficiency is still not established as risk factor for thrombosis, we assessed the absolute risk of venous and arterial thromboembolism in a family cohort study. Annual incidences in first-degree relatives with and without protein S deficiency type III were compared. Probands had experienced thrombosis and had either the prothrombin G20210A mutation, increased factor VIII:C levels or hyperhomocysteinemia. Relatives were tested for these thrombophilic disorders and factor V Leiden. Levels of antithrombin, protein C, total and free protein S, and factor XI:C were additionally measured. Of 500 relatives enrolled, 105 were excluded from analysis because they could not be classified, due to acquired conditions. Protein S deficiency type III was demonstrated in 60/395 remaining relatives (15%). Other thrombophilic defects were equally distributed among deficient and non-deficient relatives. Annual incidences of venous thromboembolism were 0.28 per 100 person-years [95% confidence interval (CI), 0.09-0.66] in deficient relatives versus 0.20 per 100 person-years (95% CI, 0.12-0.30) in non-deficient relatives [hazard ratio, 1.4 (95% CI, 0.4-4.0)]. For arterial thromboembolism these values were 0.16 per 100 person-years (95% CI, 0.03-0.46) versus 0.10 per 100 person-years (95% CI, 0.05-0.19) [hazard ratio, 1.5 (95% CI, 0.3-6.0)]. These results suggest that protein S deficiency type III is not associated with an increased risk of either venous or arterial thromboembolism.

Difference in absolute risk of venous and arterial thrombosis between familial protein S deficiency type I and type III. Results from a family cohort study to assess the clinical impact of a laboratory test-based classification

Hereditary protein S (PS) deficiency type I is an established risk factor for venous thromboembolism. Contradictionary data on type III deficiency suggests a difference in risk between both types. We studied 156 first degree relatives (90% of eligible relatives) from type I deficient probands (cohort 1) and 268 (88%) from type III deficient probands (cohort 2) to determine the absolute risk of venous and arterial thromboembolism. Annual incidences of venous thromboembolism were 1.47 and 0.17 per 100 person-years in deficient and non-deficient relatives in cohort 1 [relative risk (RR) 8.9; 95% confidence interval (CI) 2.6-30.0], and 0.27 vs. 0.24 in cohort 2 (RR 0.9; 95% CI 0.4-2.2). Type III deficiency was demonstrated in 20% of non-deficient relatives in cohort 1 and the annual incidence in this subgroup was 0.70 (RR 4.3;0.95-19.0). The cut-off level of free PS to identify subjects at risk was 30%, the lower limit of its normal range (65%). PS deficiency was not a risk factor for arterial thromboembolism. In conclusion, type I deficiency was found to be a strong risk factor for venous thromboembolism, in contrast with type III deficiency. This was because of lower free PS levels in type I deficient subjects and a free PS cut-off level far below the lower limit of its normal range.

Individual time within target range in patients treated with vitamin K antagonists: main determinant of quality of anticoagulation and predictor of clinical outcome. a retrospective study of 2300 consecutive patients with venous thromboembolism

The efficacy and safety of vitamin K antagonists (VKA) are related to the actual level of anticoagulation (given as the international normalized ratio, INR). It is often difficult to maintain an optimal INR over time. We assessed the clinical impact of the individual time spent within INR target range (ITTR) in 2304 consecutive patients with venous thromboembolism. Annual incidences of recurrent thromboembolism and major bleeding were 6.2% and 2.8% respectively. The relative risk (RR) of thromboembolism was 4.5 [95% confidence interval (CI) 3.1-6.6, P < 0.001] at INR < 2.0, for major bleeding it was 6.4 (2.5-16.1, P < 0.001) at INR > 5.0, compared with INR 2.0-3.0. Patients with ITTR < 45% were at higher risk than those with ITTR > 65% (RR 2.8, 1.9-4.3, P < 0.001), while no difference was demonstrated comparing ITTR 45-65% and ITTR > 65% (RR 1.2, 0.7-1.8, P = 0.54). Annual incidences of recurrent thromboembolism were 16.0%, 4.9% and 4.6% at ITTR < 45%, 45-60% and >65% respectively. For major bleeding these were 8.7%, 2.1% and 1.9% respectively. ITTR < 37% during the first 30 treatment days was highly predictive for the total treatment time ITTR < 45% (RR 24.2, 13.5-43.1, P < 0.001). In conclusion, ITTR can be used to identify patients on VKA at risk of recurrent thromboembolism or major bleeding. Since the 30-d ITTR is highly predictive for total treatment ITTR, these patients can be identified soon after start of treatment.

The contribution of inherited and acquired thrombophilic defects, alone or combined with antiphospholipid antibodies, to venous and arterial thromboembolism in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is associated with an increased risk of venous (VTE) and arterial thromboembolism (ATE). Lupus anticoagulant (LA) and anticardiolipin antibodies (ACAs) are established risk factors. We assessed the contribution of deficiencies of antithrombin, protein C, total protein S, factor V Leiden, the prothrombin G20210A mutation and APC resistance, either alone or in various combinations with LA and/or ACAs, to the thrombotic risk in a cohort of 144 consecutive patients with SLE. Median follow-up was 12.7 years. VTE had occurred in 10% and ATE in 11% of patients. LA,ACAs, factor V Leiden, and the prothrombin mutation were identified as risk factors for VTE. Annual incidences of VTE were 2.01 (0.74-4.37) in patients with one of these disorders and 3.05 (0.63-8.93) in patients with 2 disorders. The risk of VTE was 20- and 30-fold higher, respectively, compared with the normal population. In contrast with LA and ACAs, thrombophilic disorders did not influence the risk of ATE. In conclusion, factor V Leiden and the prothrombin mutation contribute to the risk of VTE in patients with SLE, and potentiate this risk when one of these thrombophilic defects are combined with LA and/or ACAs.

Recombinant factor VIIa in orthotopic liver transplantation: influence on parameters of coagulation and fibrinolysis

The effect of recombinant factor VIIa (rFVIIa) on blood loss was evaluated in cirrhotic patients undergoing orthotopic liver transplantation. In the present study, we explored the effect of rFVIIa on coagulation and fibrinolysis during orthotopic liver transplantation. Coagulation factors, parameters of thrombin generation and parameters of fibrinolysis were measured in six patients who had received a single dose of 80 micro g/kg rFVIIa and in ten controls, during and after orthotopic liver transplantation. Baseline concentrations and course of coagulation factors were similar in patients and controls. Thrombin generation did not rise after the administration of rFVIIa, but showed a sharp increase after reperfusion in patients, as compared with controls. No difference in fibrinolysis was apparent between patients and controls. No evidence of diffuse intravascular coagulation was seen. We conclude that the use of rFVIIa in orthotopic liver transplantation seems to enhance thrombin generation in a localized and time-limited matter, without causing systemic coagulation.

Co-segregation of thrombophilic disorders in factor V Leiden carriers; the contributions of factor VIII, factor XI, thrombin activatable fibrinolysis inhibitor and lipoprotein(a) to the absolute risk of venous thromboembolism

BACKGROUND AND OBJECTIVES

The clinical expression of factor V Leiden varies widely within and between families and only a minority of carriers will ever develop venous thromboembolism. Co-segregation of thrombophilic disorders is a possible explanation. Our aim was to assess the contributions of high levels of factor VIII:C, factor XI:C, thrombin activatable fibrinolysis inhibitor (TAFI) and lipoprotein (a) (Lp(a)) to the risk of venous thromboembolism in factor V Leiden carriers.

DESIGN AND METHODS

Levels of the four proteins were measured, in addition to tests of deficiencies for antithrombin, protein C and protein S, and the prothrombin G20210A mutation, in 153 factor V Leiden carriers, derived from a family cohort study. The (adjusted) relative risk and absolute risk of venous thromboembolism for high levels of each protein were calculated.

RESULTS

Of carriers, 60% had one or more concomitant thrombophilic disorders. Crude odds ratios (95% CI) of venous thromboembolism for high protein levels were: 3.2 (1.1-9.3) (factor VIII:C); 1.7 (0.6-4.9) (factor XI:C); 3.0 (1.1-8.2) (TAFI); and 1.9 (0.7-5.7) (Lp(a)). Adjusted for age, sex, other concomitant thrombophilic disorders and exogenous risk factors, the odds ratio for venous thromboembolism were 2.7 (0.8-8.7) for high factor VIII:C levels and 1.8 (0.6-5.3) for high TAFI levels. Annual incidences in subgroups of carriers were 0.35% (0.09-0.89), 0.44% (0.05-1.57) and 0.94% (0.35-2.05) for concomitance of high levels of factor VIII:C, TAFI and both, respectively, as compared to 0.09% (0.00-0.48) in single factor V Leiden carriers and 1.11% (0.30-2.82) for other concomitant disorders.

INTERPRETATION AND CONCLUSIONS

High levels of factor VIII:C and TAFI, in contrast with factor XI:C and Lp(a), are mild risk factors for venous thromboembolism, and substantially contribute to the risk of venous thromboembolism in factor V Leiden carriers. Our data support the hypothesis that the clinical expression of factor V Leiden depends on co-segregation of thrombophilic disorders.

Protein C/S ratio, an accurate and simple tool to identify carriers of a protein C gene mutation

Hereditary protein C deficiency is demonstrated by lowered protein C plasma levels in a patient and at least one first-degree relative. This approach is insufficient in some cases owing to overlapping protein C levels in carriers and non-carriers of a protein C gene mutation. The protein C/S ratio is a simple and more accurate tool to detect carriers. In four families, 62% of 29 carriers, compared with none of 39 non-carriers, were protein C deficient. Sensitivity and specificity of the protein C/S ratio were 90% and 92% respectively. The protein C/S ratio seems to be more accurate than the measurement of protein C levels alone to identify carriers of a protein C gene mutation.

Selective bowel decontamination in elective liver transplantation: no improvement in endotoxaemia, initial graft function and post-operative morbidity

Peri-operative endotoxaemia during liver transplantation has been linked to compromised graft function and infection. Selective decontamination of the digestive tract (SDD) could prevent endotoxaemia by eradicating Gram-negative bacteria from the intestine. In a randomized placebo controlled study we investigated the effects of endotoxaemia and the efficacy of SDD to prevent its occurrence. Thirty-one patients undergoing elective orthotopic liver transplantation received either SDD ( n=15) or placebo ( n=16), which was started at least 7 days before transplantation. Endotoxin levels were measured in blood peroperatively. Patients were scored daily for signs of liver dysfunction and infection. Endotoxaemia was neither associated with initial poor function nor any routine liver function test. Infections were more prominent in patients without endotoxaemia. SDD did not prevent endotoxaemia. Endotoxaemia does not affect post-operative graft function or the incidence of post-operative infections. SDD cannot prevent peri-operative endotoxaemia. Translocation of endotoxin may not be relevant in liver transplantation.