Patient self-management of oral anticoagulation with vitamin K antagonists in everyday practice: clinical outcomes in a single centre cohort after long-term follow-up

Background

Patient self-management (PSM) of vitamin K antagonists (VKA) seems a very promising model of care for oral anticoagulation in terms of efficacy and safety. In comparison with other management models of VKA therapy, the number of scientific publications supporting the advantages of PSM is more limited. Currently, most of the scarce information comes from randomized clinical trials. Moreover, a small number of studies have assessed PSM of VKA therapy in real life conditions.

Methods

We analyzed clinical outcomes of 927 patients in a single center (6018.6 patient-years of follow-up). Recruitment took place between 2002 and 2017. All patients followed a structured training program, conducted by specialized nurses.

Results

Fifty percent of individuals had a mechanical heart valve (MHV), 23% suffered from recurrent venous thromboembolism (VTE) or high-risk thrombophilia, and 13% received VKA therapy because of atrial fibrillation (AF). Median follow-up was 6.5 years (range 0.1–15.97 years), median age was 58.1 years (IQR 48–65.9) and 46.5% were women. The incidence of major complications (either hemorrhagic or thromboembolic) was 1.87% patient-years (pt-ys) with a 95% CI of 1.54–2.27. The incidence of major thromboembolic events was 0.86% pt-ys (95% CI 0.64–1.13) and that of major hemorrhagic events was 1.01% pt-ys (95% CI 0.77–1.31). The incidence of intracranial bleeding was 0.22% pt-ys (95% CI 0.12–0.38). In terms of clinical indication for VKA therapy, the incidence of total major complications was 2.4% pt-ys, 2.0% pt-ys, 0.9% pt-ys and 1.34% pt-ys for MHV, AF, VTE and other (including valvulopathies and myocardiopathies), respectively. Clinical outcomes were worse in patients with multiple comorbidities, previous major complications during conventional VKA therapy, and in older individuals. The percentage of time in therapeutic range (TTR) was available in 861 (93%) patients. Overall, the mean (SD) of TTR was 63.6 ± 13.4%, being higher in men (66.2 ± 13.1%) than women (60.6 ± 13.2%), p < 0.05.

Conclusions

In terms of clinically relevant outcomes (incidence of major complications and mortality), PSM in real life setting seems to be a very good alternative in properly trained patients.

Antitumoral effect of maintained neutrophilia induced by rhG-CSF in a murine model of pancreatic cancer

Although the protumoral functions of polymorphonuclear neutrophils are well known, some now-forgotten studies report antitumoral roles for these cells. The present work examines the antitumoral effect of maintained neutrophilia induced via the injection of recombinant human granulocyte colony stimulating factor (rhG-CSF, 100 μg/kg/day) in a Panc-1 subcutaneous xenograft murine model of pancreatic cancer. This treatment was compared with gemcitabine administration (120 mg/kg every two days) and a saline control (n = 6–7 mice per group). Compared to the controls, both the rhG-CSF- and gemcitabine-treated mice showed significantly suppressed tumor growth by day 4 (p < 0.001 and p = 0.013 respectively). From a mean starting volume of 106.9 ± 3.1 mm³ for all treatment groups, the final mean tumor volumes reached were 282.0 ± 30.7 mm³ for the rhG-CSF-treated mice, 202.6 ± 18.1 mm³ for the gemcitabine-treated mice and 519.4 ± 62.9 mm³ for the control mice (p < 0.004 and p < 0.01, respectively, vs. control). The rhG-CSF-treated tumors showed higher percentage necrosis than those treated with gemcitabine (37.4 ± 4.6 vs. 7.5 ± 3.0; p < 0.001). This is the first report of a clear anti-tumoral effect of rhG-CSF when used in monotherapy against pancreatic cancer. Since rhG-CSF administration is known to be associated with very few adverse events, it may offer an attractive alternative in the clinical treatment of pancreatic cancer.

Coagulation factor XII genetic variation, ex vivo thrombin generation, and stroke risk in the elderly: results from the Cardiovascular Health Study

BACKGROUND

The relationships of thrombin generation (TG) with cardiovascular disease risk are underevaluated in population-based cohorts.

OBJECTIVES

To evaluate the relationships of TG influenced by the contact and tissue factor coagulation pathways ex vivo with common single-nucleotide polymorphisms (SNPs) and incident cardiovascular disease and stroke.

PATIENTS/METHODS

We measured peak TG (pTG) in baseline plasma samples of Cardiovascular Health Study participants (n = 5411), both with and without inhibitory anti-factor XIa antibody (pTG/FXIa(-) ). We evaluated their associations with ~ 50 000 SNPs by using the IBCv2 genotyping array, and with incident cardiovascular disease and stroke events over a median follow-up of 13.2 years.

RESULTS

The minor allele for an SNP in the FXII gene (F12), rs1801020, was associated with lower pTG in European-Americans (β = - 34.2 ± 3.5 nm; P = 3.3 × 10(-22) ; minor allele frequency [MAF] = 0.23) and African-Americans (β = - 31.1 ± 7.9 nm; P = 9.0 × 10(-5) ; MAF = 0.42). Lower FXIa-independent pTG (pTG/FXIa(-) ) was associated with the F12 rs1801020 minor allele, and higher pTG/FXIa(-) was associated with the ABO SNP rs657152 minor allele (β = 16.3 nm; P = 4.3 × 10(-9) ; MAF = 0.37). The risk factor-adjusted ischemic stroke hazard ratios were 1.09 (95% confidence interval CI 1.01-1.17; P = 0.03) for pTG, 1.06 (95% CI 0.98-1.15; P = 0.17) for pTG/FXIa(-) , and 1.11 (95% CI 1.02-1.21; P = 0.02) for FXIa-dependent pTG (pTG/FXIa(+) ), per one standard deviation increment (n = 834 ischemic strokes). In a multicohort candidate gene analysis, rs1801020 was not associated with incident ischemic stroke (β = - 0.02; standard error = 0.08; P = 0.81).

CONCLUSIONS

These results support the importance of contact activation pathway-dependent TG as a risk factor for ischemic stroke, and indicate the importance of F12 SNPs for TG ex vivo and in vivo.

Economic analysis of thrombo inCode, a clinical-genetic function for assessing the risk of venous thromboembolism

BACKGROUND

Patients with venous thromboembolism (VTE) commonly have an underlying genetic predisposition. However, genetic tests nowadays in use have very low sensitivity for identifying subjects at risk of VTE. Thrombo inCode(®) is a new genetic tool that has demonstrated very good sensitivity, thanks to very good coverage of the genetic variants that modify the function of the coagulation pathway.

OBJECTIVE

To conduct an economic analysis of risk assessment of VTE from the perspective of the Spanish National Health System with Thrombo inCode(®) (a clinical-genetic function for assessing the risk of VTE) versus the conventional/standard method used to date (factor V Leiden and prothrombin G20210A).

METHODS

An economic model was created from the National Health System perspective, using a decision tree in patients aged 45 years with a life expectancy of 81 years. The predictive capacity of VTE, based on identification of thrombophilia using Thrombo inCode(®) and using the standard method, was obtained from two case-control studies conducted in two different populations (S. PAU and MARTHA; 1,451 patients in all). Although this is not always the case, patients who were identified as suffering from thrombophilia were subject to preventive treatment of VTE with warfarin, leading to a reduction in the number of VTE events and an increased risk of severe bleeding. The health state utilities (quality-adjusted life-years [QALYs]) and costs (in 2013 EUR values) were obtained from the literature and Spanish sources.

RESULTS

On the basis of a price of EUR 180 for Thrombo inCode(®), this would be the dominant option (more effective and with lower costs than the standard method) in both populations. The Monte Carlo probabilistic analyses indicate that the dominance would occur in 100 % of the simulations in both populations. The threshold price of Thrombo inCode(®) needed to reach the incremental cost-effectiveness ratio (ICER) generally accepted in Spain (EUR 30,000 per QALY gained) would be between EUR 3,950 (in the MARTHA population) and EUR 11,993 (in the S. PAU population).

CONCLUSION

According to the economic model, Thrombo inCode(®) is the dominant option in assessing the risk of VTE, compared with the standard method currently used.

Association of complement receptor 2 polymorphisms with innate resistance to HIV-1 infection

HIV-1 induces activation of complement through the classical and lectin pathways. However, the virus incorporates several membrane-bound or soluble regulators of complement activation (RCA) that inactivate complement. HIV-1 can also use the complement receptors (CRs) for complement-mediated antibody-dependent enhancement of infection (Ć-ADE). We hypothesize that hypofunctional polymorphisms in RCA or CRs may protect from HIV-1 infection. For this purpose, 139 SNPs located in 19 RCA and CRs genes were genotyped in a population of 201 Spanish HIV-1-exposed seronegative individuals (HESN) and 250 HIV-1-infected patients. Two SNPs were associated with infection susceptibility, rs1567190 in CR2 (odds ratio (OR) = 2.27, P = 1 × 10(-4)) and rs2842704 in C4BPA (OR = 2.11, P = 2 × 10(-4)). To replicate this finding, we analyzed a cohort of Italian, sexually HESN individuals. Although not significant (P = 0.25, OR = 1.57), similar genotypic proportions were obtained for the CR2 marker rs1567190. The results of the two association analyses were combined through a random effect meta-analysis, with a significant P-value of 2.6 x 10(-5) (OR = 2.07). Furthermore, we found that the protective CR2 genotype is correlated with lower levels CR2 mRNA as well as differences in the ratio of the long and short CR2 isoforms.

Genetic determinants of plasma β₂-glycoprotein I levels: a genome-wide association study in extended pedigrees from Spain

BACKGROUND

β2 -Glycoprotein I (β2 -GPI), also designated apolipoprotein H, is a 50-kDa protein that circulates in blood at high concentrations, playing important roles in autoimmune diseases, hemostasis, atherogenesis, and angiogenesis, as well as in host defense against bacteria and in protein/cellular waste removal. Plasma β2 -GPI levels have a significant genetic component (heritability of ~ 80%).

OBJECTIVES

To present the results of a genome-wide association study for plasma β2 -GPI levels in a set of extended pedigrees from the Genetic Analysis of Idiopathic Thrombophilia (GAIT) Project.

PATIENTS/METHODS

A total of 306 individuals for whom β2 -GPI plasma measurements were available were typed for 307,984 single-nucleotide polymorphisms (SNPs) with the Infinium 317k Beadchip (Illumina). Association with the β2 -GPI phenotype was investigated through variance component analysis, and the most significant results were followed up for association with coronary artery disease (CAD) in an independent in silico analysis involving 5765 CAD cases from the PROCARDIS Project and 7264 controls from the PROCARDIS Project and the Wellcome Trust Case Control Consortium (WTCCC) collection.

RESULTS

After correction for multiple testing, three SNPs located in/around two genes (ELF5 and SCUBE2) reached genome-wide significance. Moreover, an SNP in the APOH gene showed suggestive association with the β2 -GPI phenotype. Some of the identified genes are plausible biological candidates, as they are actually or potentially involved in inflammatory processes.

CONCLUSIONS

Our results represent a first step towards identifying common variants reflecting the genetic architecture influencing plasma β2 -GPI levels, and warrant further validation by functional experiments, as the functions of some of the discovered loci are still unknown.

SNP sets selection under mutual information criterion, application to F7/FVII dataset

One of the main goals of human genetics is to find genetic markers related to complex diseases. In blood coagulation process, it is known that genetic variability in F7 gene is the most responsible for observed variations in FVII levels in blood. In this work, we propose a method for selecting sets of Single Nucleotide Polymorphisms (SNPs) significantly correlated with a phenotype (FVII levels). This method employs a feature selection algorithm (variant of Sequential Forward Selection, SFS) based on a criterion of statistical significance of a mutual information functional. This algorithm is applied to a sample of independent individuals from the GAIT project. Main SNPs found by the algorithm are in correspondence with previous results published using family-based techniques.

Low-molecular-weight heparin as bridging therapy during interruption of oral anticoagulation in patients undergoing colonoscopy or gastroscopy

Nowadays, most patients under oral anticoagulant therapy (OAT) require invasive procedures such as colonoscopy (CC) or gastroscopy (GC). The goals of the management of OAT are to minimise the risk of thromboembolism and bleeding. We have performed the first prospective, observational study to evaluate these parameters using fixed-dose high-risk thromboprophylactic therapy with sodic bemiparin (Hibor) as bridging therapy. From January 2004 to January 2005, patients under OAT were included. Periprocedure prophylaxis consisted of: Acenocumarol patients: Day -3: withdrawal acenocumarol. Days -2,-1,0: Hibor 3500 UI/d sc and days +1,+2,+3: Hibor 3500 U/I + acenocumarol. And day +5: acenocumarol only. Warfarin patients: Days -5,-4: withdrawal warfarin, -3,-2,-1, 0; Hibor 3500 UI/day sc, days +1,+2,+3,+4: Hibor 3500 UI/day sc and warfarin and day +5; warfarin only. Thromboembolic complications and bleeding were recorded in a 3 month follow-up. We included 100 consecutive patients in the intention-to-treat group. The remaining 98 patients were 50 women and 48 men. Mean age of women was 71.1 (range: 46-87) years and 70.7 (range: 39-86) years in men. Eighty-three took acenocumarol, and 15 warfarin. Thirty-two gastroscopies and 61 colonoscopies were performed and in five patients both were performed. No thromboembolic and bleeding complications related to bemiparin were observed in the 103 endoscopies. Two patients developed pruritus at the punction site. Fixed-dose high-risk thromboprophilactic therapy with bemiparin (Hibor) is safe and effective as a bridging therapy in patients under OAT who require GC or CC.

Genetic determinants of normal variation in coagulation factor (F) IX levels: genome-wide scan and examination of the FIX structural gene

BACKGROUND

High-normal and elevated plasma FIX activity (FIX:C) levels are associated with increased risk for venous- and possibly arterial-thrombosis.

OBJECTIVE

Because the broad normal range for FIX:C involves a substantial unknown genetic component, we sought to identify quantitative-trait loci (QTLs) for this medically important hemostasis trait.

METHODS

We performed a genome-wide screen and a resequencing-based variation scan of the known functional regions of every distinct FIX gene (F9) in the genetic analysis of idiopathic thrombophilia project (GAIT), a collection of 398 Spanish-Caucasians from 21 pedigrees.

RESULTS

We found no evidence for linkage (LOD scores <1.5) despite genotyping more than 540 uniformly-spaced microsatellites. We identified 27 candidate F9 polymorphisms, including three in cis-elements responsible for the increase in FIX:C that occurs with aging, but found no significant genotype-specific differences in mean FIX:C levels (P-values > or = 0.11) despite evaluating every polymorphism in GAIT by marginal multicovariate measured-genotype association analysis.

CONCLUSIONS

The heritable component of interindividual FIX:C variability likely involves a collection of QTLs with modest effects that may reside in genes other than F9. Nevertheless, because the alleles of these 27 polymorphisms exhibited a low overall degree of linkage disequilibrium, we are currently defining their haplotypes to interrogate several highly-conserved non-exonic sequences and other F9 segments not examined here.

A Locus on Chromosome 13 Influences Levels of TAFI Antigen in Healthy Mexican Americans

When activated, thrombin activatable fibrinolysis inhibitor (TAFI) inhibits fibrinolysis by modifying fibrin, depressing its plasminogen binding potential. Polymorphisms in the TAFI structural gene (CPB2) have been associated with variation in TAFI levels, but the potential occurrence of influential quantitative trait loci (QTLs) located elsewhere in the genome has been explored only in families ascertained in part through probands affected by thrombosis. We report the results of the first genome-wide linkage screen for QTLs that influence TAFI phenotypes. Data are from 635 subjects from 21 randomly ascertained Mexican American families participating in the San Antonio Family Heart Study. Potential QTLs were localized through a genome-wide multipoint linkage scan using 417 highly informative autosomal short tandem repeat markers spaced at approximately 10-cM intervals. We observed a maximum multipoint LOD score of 3.09 on chromosome 13q, the region of the TAFI structural gene. A suggestive linkage signal (LOD = 2.04) also was observed in this region, but may be an artifact. In addition, weak evidence for linkage occurred on chromosomes 17p and 9q. Our results suggest that polymorphisms in the TAFI structural gene or its nearby regulatory elements may contribute strongly to TAFI level variation in the general population, although several genes in other regions of the genome may also influence variation in this phenotype. Our findings support those of the Genetic Analysis of Idiopathic Thrombophilia (GAIT) project, which identified a potential TAFI QTL on chromosome 13q in a genome-wide linkage scan in Spanish thrombophilia families.

A Locus on Chromosome 2 Influences Levels of Tissue Factor Pathway Inhibitor

Objective— Levels of tissue factor pathway inhibitor (TFPI) have been associated with arteriosclerosis and thrombotic disease. Although a genetic component to variation in TFPI levels is well-documented, no systematic genome-wide screens have been conducted to localize genes influencing levels of TFPI.

Methods and Results— We studied TFPI levels in 397 individuals in 21 Spanish families participating in the Genetic Analysis of Idiopathic Thrombosis (GAIT) study. Twelve families were selected through a proband with idiopathic thrombosis and 9 were ascertained without regard to phenotype. A genome scan was performed using microsatellite markers spaced at approximately 10 cM intervals. Standard multipoint variance component linkage methods were used. The heritability of TFPI levels was 0.52 ( P <0.0001), with no evidence for shared household effects. In the genome screen, only 1 LOD score >2 was observed. On chromosome 2q, the maximum multipoint LOD score was 3.52 near marker D2S1384. This is near the structural gene for TFPI, which is located at 2q32. In follow-up association analyses, marginal evidence of association ( P =0.04) was observed with the TFPI promoter variant C-399T.

Conclusion— These results suggest that polymorphisms in and around the TFPI structural gene may be the major genetic determinants of variation in TFPI levels.

Risk of a first venous thrombotic event in carriers of a familial thrombophilic defect. The European Prospective Cohort on Thrombophilia (EPCOT)

BACKGROUND

Reliable risk estimates for venous thrombosis in families with inherited thrombophilia are scarce but necessary for determining optimal screening and treatment policies.

OBJECTIVES

In the present analysis, we determined the risk of a first venous thrombotic event in carriers of a thrombophilic defect (i.e. antithrombin-, protein C- or protein S deficiency, or factor V Leiden).

PATIENTS AND METHODS

The asymptomatic carriers had been tested prior to this study in nine European thrombosis centers because of a symptomatic carrier in the family, and were followed prospectively for 5.7 years on average between March 1994 and January 2001. Annually, data were recorded on the occurrence of risk situations for venous thrombosis and events (e.g. venous thrombosis, death).

RESULTS

Twenty-six of the 575 asymptomatic carriers (4.5%) and seven of the 1118 controls (0.6%) experienced a first deep venous thrombosis or pulmonary embolism during follow-up. Of these events, 58% occurred spontaneously in the carriers compared with 43% in the controls. The incidence of first events was 0.8% per year (95% CI 0.5-1.2) in the carriers compared with 0.1% per year (95% CI 0.0-0.2) in the controls. The highest incidence was associated with antithrombin deficiency or combined defects, and the lowest incidence with factor V Leiden.

CONCLUSIONS

The incidence of venous events in asymptomatic individuals from thrombophilic families does not exceed the risk of bleeding associated with long-term anticoagulant treatment in the literature (1-3%).

Familial thrombophilia and lifetime risk of venous thrombosis

BACKGROUND

We started a large multicenter prospective follow-up study to provide reliable risk estimates of venous thrombosis in families with various thrombophilic defects.

OBJECTIVES

This paper describes data collected at study entry on venous events experienced before study inclusion, i.e. the baseline data.

PATIENTS/METHODS

All individuals (probands, relatives) registered in nine European thrombosis centers with the factor (F)V Leiden mutation, a deficiency of antithrombin, protein C or protein S, or a combination of these defects, were enrolled between March 1994 and September 1997. As control individuals, partners, friends or acquaintances of the thrombophilic participants were included. Incidence and relative risk of objectively confirmed venous thrombotic events (VTEs) prior to entry were calculated for the relatives with thrombophilia and the controls.

RESULTS

Of the 846 relatives with thrombophilia (excluding probands), 139 (16%) had experienced a VTE with an incidence of 4.4 per 1000 person years. Of the controls, 15 of the 1212 (1%) controls had experienced a VTE with an incidence of 0.3 per 1000 person years. The risk of venous thrombosis associated with familial thrombophilia was 15.7 (95% CI 9.2-26.8) and remained similar after adjustment for regional and sex-effects (16.4; 95% CI 9.6-28.0). The highest incidence per 1000 person years was found in relatives with combined defects (8.4; 95% CI 5.6-12.2), and the lowest incidence was found in those with the FV Leiden mutation (1.5; 95% CI 0.8-2.6).

CONCLUSIONS

Considerable differences in the lifetime risk of VTE were observed among individuals with different thrombophilia defects.

Hereditary thrombophilia and fetal loss: a prospective follow-up study

BACKGROUND

As the placental vessels are dependent on the normal balance of procoagulant and anticoagulant mechanisms, inherited thrombophilia may be associated with fetal loss.

OBJECTIVES

We performed a prospective study to investigate the relation between inherited thrombophilia and fetal loss, and the influence of thromboprophylaxis on pregnancy outcome.

PATIENTS AND METHODS

Women were enrolled in the European Prospective Cohort on Thrombophilia (EPCOT). These included women with factor (F)V Leiden or a deficiency of antithrombin, protein C or protein S. Controls were partners or acquaintances of thrombophilic individuals. A total of 191 women (131 with thrombophilia, 60 controls) had a pregnancy outcome during prospective follow-up. Risk of fetal loss and effect of thromboprophylaxis were estimated by frequency calculation and Cox regression modelling.

RESULTS

The risk of fetal loss appeared slightly increased in women with thrombophilia without a previous history of fetal loss who did not use any anticoagulants during pregnancy (7/39 vs. 7/51; relative risk 1.4; 95% confidence interval 0.4, 4.7). Per type of defect the relative risk varied only minimally from 1.4 for FV Leiden to 1.6 for antithrombin deficiency compared with control women. Prophylactic anticoagulant treatment during pregnancy in 83 women with thrombophilia differed greatly in type, dose and duration, precluding solid conclusions on the effect of thromboprophylaxis on fetal loss. No clear benefit of anticoagulant prophylaxis was apparent.

CONCLUSIONS

Women with thrombophilia appear to have an increased risk of fetal loss, although the likelihood of a positive outcome is high in both women with thrombophilia and in controls.

Risk of ischemic stroke associated with functional thrombin-activatable fibrinolysis inhibitor plasma levels

BACKGROUND AND PURPOSE

Recently, a novel procarboxypeptidase B-like proenzyme, called thrombin-activatable fibrinolysis inhibitor (TAFI), has been described. It plays an important role in the delicate balance between coagulation and fibrinolysis. TAFI leads to potent inhibition of tissue plasminogen activator-induced fibrinolysis. The relevance of TAFI in thromboembolic disease is unclear. We have investigated the risk of ischemic stroke (IS) in relation to plasma levels of functional TAFI.

METHODS

In a case-control study, we enrolled 264 individuals; 114 had IS, and 150 were recruited as controls who were age and sex matched and had no history of arterial disease. The individuals supplied information on their personal and family histories of cardiovascular diseases and conventional cardiovascular risk factors. Functional TAFI assays were performed by use of a method based on the activation of TAFI with thrombin-thrombomodulin and the measure of the TAFI activity generated. Other hemostatic parameters assayed were factor VIIIc, anti-phospholipid antibodies,fibrinogen, factor V Leiden, and the prothrombin gene G20210A mutations (PT20210A).

RESULTS

Functional TAFI levels were significantly higher in patients with IS (113.7+/-25%; range, 57% to 209%) than in controls (102.6+/-19%). The odds ratio for IS in patients with functional TAFI levels >120% was 5.7 (95% confidence interval, 2.3 to 14.1).

CONCLUSIONS

We found that functional TAFI levels in plasma (>120%) increased the risk of IS approximately 6-fold. Further studies should elucidate the physiological role of TAFI in arterial disease and possibly provide clues to therapeutic approaches.

Enhanced risk of thrombotic disease in patients with acquired vitamin B12 and/or folate deficiency: role of hyperhomocysteinemia

A number of studies have identified elevated levels of homocysteine (Hcy) as a risk factor for thrombosis. Given the relationship between Hcy and thrombosis, a high prevalence of thrombosis would be expected in patients with megaloblastic anemia. The aim of our study was to determine whether an acquired vitamin B12/folate deficiency is a risk factor for thrombosis. A retrospective case and control study was performed that included 193 cases with reduced levels of vitamin B12/folate. The cases were divided initially into two groups (105 with serum vitamin B12 < or =150 pmol/l and/or low red cell folate < or = 450 nmol/l and 88 with serum vitamin B12 between 150 and 200 pmol/l and/or red cell folate between 450 and 590 nmol/l). The control group consisted of 87 additional patients who had normal levels of serum vitamin B12, red cell folate, and normal renal function. Serum Hcy, thrombotic events, and risk factors were evaluated in all participants. Eight patients (9%) in the control group had had previous vascular events although only three of these events (37.5%) were observed between the vitamin study and 2 years prior to the study. In the case group, 20% of the patients had a history of thrombosis. In contrast with controls, 85% of cases suffered thrombosis between the time they were diagnosed and 2 years prior to the time they were diagnosed as showing a vitamin deficiency. Multivariate analysis demonstrated that vitamin deficiency was a significant risk factor for arterial thrombosis [adjusted odds ratio (OR) 3.3, confidence interval (CI) 1.1-10.2]. However, when hyperhomocysteinemia was included in the analysis, vitamin deficiency was no longer a risk factor, suggesting that hyperhomocysteinemia was responsible for arterial thrombotic risk in these patients (adjusted OR 2.5, CI 1.1-5.8). As a consequence of hyperhomocysteinemia, patients with acquired vitamin deficiency of vitamin B12/folate had a high risk of thrombosis. However, a more extensive study that controls risk variables and genetic factors is needed to sort out the various contributing factors.

Contribution of prothrombin 20210A allele and factor V Leiden mutation to thrombosis risk in thrombophilic families with other hemostatic deficiencies

BACKGROUND AND OBJECTIVES

The aims of this study were to compare the lifetime probability of developing thrombosis in 722 relatives of 132 thrombophilic families of symptomatic probands with recognized thrombophilic defects and to determine the prevalence of the factor V Leiden (FVL) mutation and the 20210A allele of the prothrombin gene (PT20210A) in these families.

DESIGN AND METHODS

The study included 722 members belonging to 132 unrelated families. The propositi were patients who had been referred to our Thrombosis Unit. The families were selected through a symptomatic proband. Once a patient with a deficiency or mutation was identified, family members were screened for the same defect.

RESULTS

The prevalence of FVL and PT20210A in families with other thrombophilic defects was higher than expected. Compared with non-deficient individuals, the risk of venous thrombosis was increased in subjects with antithrombin (AT), protein S (PS) and protein C (PC) deficiencies, and in carriers of FVL and PT20210A mutations. The risk of thrombosis was significantly increased for individuals with combined genetic defects (PC-FVL, PS-FVL, PS-PT20210A and FVL-PT20210A). The ages at the time of 50% thrombosis-free survival were as follows: 34 years for AT deficiency, (19 years with FVL, 21 years with PT20210A), 62 years for PC deficiency (33 years with FVL, 44 years with PT20210A), 37 years for PS deficiency (24 years with FVL, 36 years with PT20210A), 50 years for the FVL mutation (52 years with PT20210A), and 65 years for the PT20210A mutation. As for clinical characteristics, no differences were observed except for the higher frequency of oral contraceptive-related thrombosis in women who were carriers of PT20210A or FVL.

INTERPRETATION AND CONCLUSIONS

Based on these results, screening for FVL and PT20210A mutation is recommended in patients with other thrombophilic defects. To the best of our knowledge, this is the first family study, including the PT20210A mutation, that compares genetic risk factors for thrombosis and the lifelong probability of developing thrombosis.

Risk of thrombosis associated with oral contraceptives of women from 97 families with inherited thrombophilia: high risk of thrombosis in carriers of the G20210A mutation of the prothrombin gene

BACKGROUND AND OBJECTIVES

Oral contraceptives (OC) and inherited thrombophilia are well-known risk factors associated with venous thromboembolism (VTE). However, there are only few studies on the risk of VTE in women with inherited thrombophilia who use oral contraceptives.

DESIGN AND METHODS

We performed a retrospective family cohort study of 325 women belonging to 97 families with inherited thrombophilia, including antithrombin, protein S and C deficiencies, the factor V Leiden mutation (FVL) and the G20210A mutation of the prothrombin gene (PT20210A) to determine the risk of VTE associated with OC intake.

RESULTS

For carriers of the PT20210A mutation, the risk of VTE in OC users was 3-fold higher (95% CI 1.3-6.8) than that in non-carriers. Carriers of FVL mutation taking OC showed an OR of 1.4 (95% CI 0.6-3.3), indicating a tendency to increase the risk of VTE.

INTERPRETATION AND CONCLUSIONS

Because of the high prevalence of the PT20210A (6.5%) and FVL (2%) mutations in the general Spanish population and the increased risk of VTE associated with OC intake, genetic screening for these mutations should be considered in potential OC users belonging to families with thrombophilia.

Genetic regulation of plasma levels of vitamin K-dependent proteins involved in hematostatis: results from the GAIT Project. Genetic Analysis of Idiopathic Thrombophilia

Vitamin K-dependent proteins play a critical role in hemostasis. We have analysed the genetic and environmental correlations between measures of several vitamin K-dependent proteins in 21 Spanish extended families, including 397 individuals. Plasma functional levels of factors II, VII, IX, X, protein C and functional protein S were assayed in an automated coagulometer. Antigenic levels of total and free protein S were measured using an ELISA method. A maximum likelihood-based covariance decomposition analysis was used to assess the heritability of each trait and the genetic and environmental correlations between all possible pairs. All of the plasma levels had a significant genetic component (heritability) ranging from 22% to 52% of the phenotypic variance. Among the 28 possible pairs of genetic correlations, 18 were significant at a level of p < 0.05 and six exhibited a p-value between 0.05 and 0.10. Positive environmental correlation was observed for 25 of the pairs (p < 0.05). We conclude that genetic effects account for a large proportion of the observed phenotypic variation in vitamin K-dependent proteins. Some of the genes appear to pleiotropically influence all of these traits, since most pairs of phenotypes exhibit significant genetic correlation. However, since these phenotypes show a high degree of environmental correlation, it is also likely that the same environmental factors influence them co-jointly.

The effect of two different doses of aprotinin on hemostasis in cardiopulmonary bypass surgery: similar transfusion requirements and blood loss

BACKGROUND AND OBJECTIVES

Various dosages of aprotinin have proven to be effective in reducing blood loss and allogeneic transfusion requirements in cardiopulmonary bypass surgery, despite the controversy surrounding the precise hemostatic mechanisms of this drug. The aim of our prospective, randomized, double-blind study was to assess differences in blood loss and transfusion requirements and the effect of two dosages of aprotinin on hemostatic activation.

DESIGN AND METHODS

Patients undergoing coronary artery bypass grafting received high-dose aprotinin (n=28), pump-prime-only (PPO) aprotinin (n=28), or placebo (n=28).

RESULTS

The high-dose and the PPO groups had a significantly lower blood loss (985 mL [95%CI 845-1,102] and 1,255 mL, [95% CI 1,025-1,406], respectively) than the placebo group (1,416 mL, 95%CI 1,248-1,612]. Transfusion requirements were lower in the aprotinin-treated groups than in the patients receiving placebo (21 units and 15 units in the high and low-dose groups vs 59 units in placebo group). As far as concerns parameters of thrombin generation, the aprotinin groups showed a significant reduction of F1+2 prothrombin fragment but not of thrombin-antithrombin complexes. There were higher levels of natural anticoagulants, i.e. antithrombin, protein C and protein S, in the high-dose aprotinin group. As regards fibrinolysis parameters, D-dimer was lower in the aprotinin groups, and the levels of alpha2-antiplasmin and plasmin-alpha2-antiplasmin complexes were raised. In summary, both dosages of aprotinin were equally effective in reducing blood loss and transfusion requirements. There was a lower activation of coagulation and fibrinolysis in cardiopulmonary bypass patients treated with aprotinin: the levels of natural anticoagulants were less decreased in the high-dose group. No differences in thrombotic complications were observed between aprotinin groups.

INTERPRETATION AND CONCLUSIONS

Our study shows that both dosages of aprotinin are safe and effective in reducing transfusion requirements. Considering the difference in cost of using a low-dose or high-dose schedule, the former should be recommended for patients undergoing cardiopulmonary bypass surgery.

Skin necrosis at the injection site induced by low-molecular-weight heparin: case report and review

Heparin-induced skin necrosis at the injection site is a rare adverse effect, more commonly associated with standard heparins than with low-molecular-weight heparins (LMWH) and its mechanism remains unclear. We report a case of LMWH-induced skin necrosis in a female during prophylactic treatment with LMWH after a surgical procedure. Determination of heparin-platelet-factor-4(PF4)-induced antibodies was positive. This case describes the occurrence of LMWH-induced skin necrosis and antibodies to heparin-PF4 complex, suggesting that this effect is more frequent than previously suspected.

Functional effects of the ABO locus polymorphism on plasma levels of von Willebrand factor, factor VIII, and activated partial thromboplastin time

Lower levels of factor VIII and von Willebrand factor (vWF) have been reported in individuals with blood type O compared with individuals with other ABO blood types. However, this relationship has been demonstrated only by association studies and not by linkage studies. Also, it is not clear whether the ABO locus exerts a functional effect directly on these plasma factors or whether the ABO locus is in linkage disequilibrium with another locus that controls these factors. To distinguish between these 2 possibilities, we applied new statistical methods combining linkage and association tests in a pedigree-based sample. In contrast to most previous studies that used the ABO phenotypes, our study used the ABO genotypes, permitting us to distinguish AO from AA and BO from BB. Our results clearly showed significant linkage between the ABO locus and vWF antigen (P=0.00075). In addition, factor VIII coagulant activity and activated partial thromboplastin time showed suggestive linkage with the ABO locus (P=0.10 and P=0.13). All 3 plasma phenotypes showed significant differences between OO and non-OO genotypes. In addition, vWF antigen exhibited significant differences between O heterozygotes and non-OO homozygotes. This study is unique because it used a combined linkage and association test, which indicated that the ABO locus itself has a functional effect on these plasma phenotypes.

Normalisation of tissue factor pathway inhibitor activity after glycaemic control optimisation in type 1 diabetic patients

Increased plasma concentrations of various markers of endothelial damage have been observed in type I diabetic patients, particularly in those with microangiopathy.

OBJECTIVE

To evaluate the effect of near-normalisation of glycaemic control on different markers of endothelial injury involved in haemostasis in poorly-controlled type 1 diabetic patients.

MATERIAL AND METHODS

TFPI, thrombomodulin (TM), plasminogen activator inhibitor, tissue-type plasminogen activator and von Willebrand factor were measured in 14 poorly-controlled type 1 diabetic patients free of diabetes-related complications (8 men, 6 women; mean age 29.8 +/- 9.9 years) before (baseline) and after 3 months of intensive therapy and in 14 sex-, age- and BMI-matched control subjects.

RESULTS

After a mean follow-up of 107 +/- 49 days (56-210), HbA1c decreased from 11.2 +/- 2.3 to 6.7 +/- 0.7% (p <0.0001). TFPI activity at baseline was higher than in the control group (126.9 +/- 34 vs 92.0 +/- 13%, p <0.005) and decreased after good glycaemic control was achieved (p <0.005), becoming similar to that in the control group (91.0 +/- 16.5%). The TFPI descent correlated with the variations observed in HbA1c (p <0.05; r = 0.54). TM levels at baseline were significantly higher than in the control group (42.3 +/- 9.1 vs 29.00 +/- 10.9; p <0.005) and did not change. The remaining parameters studied were similar between patients and controls and did not change after glycaemic optimisation.

CONCLUSIONS

Optimisation of glycaemic control normalises the increased activity of TFPI but not the higher TM levels observed in poorly-controlled type I diabetic patients without chronic complications.

Protein S gene analysis reveals the presence of a cosegregating mutation in most pedigrees with type I but not type III PS deficiency

DNA sequence analysis of the protein S gene (PROS1) in 22 Spanish probands with type I or III PS deficiency, has allowed the identification of 10 different mutations and 2 new sequence variants in 15 probands. Nine of the mutations, 8 of which are novel, cosegregate with type I or quantitative PS deficiency in 12 of the 13 pedigrees analyzed. One of these mutations (Q238X) also cosegregates with both type I and III PS-deficient phenotypes coexisting in a type I/III pedigree. Another mutation identified in a pedigree with these two PS phenotypes is the missense mutation R520G, present in the homozygous form in the type I propositus and in the heterozygous form in his type III relatives. By contrast, no cosegregating PROS1 mutation has been found in any of the six families with only type III phenotypes. Three of these families, as well as the two families with type I and I/III phenotypes where no other PROS1 mutation has been identified, segregate the P allele of the S460P variant, although this allele does not always cosegregate with the deficient phenotype. From these results we conclude that while mutations in PROS1 are the main cause of type I PS deficiency, the molecular basis of the type III phenotype is probably more complex, with many cases not being explained by a PROS1 mutation.

Optimization of a simple and rapid single-strand conformation analysis for detection of mutations in the PROS1 gene: identification of seven novel mutations and three novel, apparently neutral, variants

Anticoagulant protein S (PS) deficiency is a known risk factor for thrombophilia. The structure and high allelic heterogeneity of the PS gene (PROS1), together with the presence of a 97% homologous pseudogene, complicates PROS1 analysis. We have optimized a simple, fast, and non-isotopic Single-Strand Conformation Analysis (SSCA or SSCP) method for PROS1 mutation detection. This is accomplished through the analysis of the single-stranded and heteroduplex DNA fragments corresponding to 15 PCR segments that include part of the 5'-upstream region and the 15 PROS1 exons with their intron boundaries. To standardize the method, 13 known PROS1 mutations or allele variants in 10 different fragments were analyzed under different electrophoretic conditions. The results indicated that, using a combination of two different electrophoretic settings, all the allele variants could be detected as a single-strand band shift and/or by the presence of a heteroduplex. This method was used to analyze the PROS1 gene in 31 propositi with different types of PS deficiency and thrombosis. Ten different cosegregating mutations, seven of which are novel (143C->G, L-27H, G96X, M599T, P626L, 1418delA, and 1877delT), were identified in the five families suffering from type I or quantitative PS deficiency and in four of the nine families with coexistence of type I and type III phenotypes. No clearly co-segregating PROS1 mutations were identified in any of the 17 type III propositi analyzed, although eight of them were heterozygotes for the uncommon P460 allele of the S/P460 variant. Furthermore, five apparently neutral allelic variants, three of which are novel (-296C->T, 182G->C and T57S), were identified in a normal control, two type I/III and two type III PS-deficient pedigrees.

Linkage analysis demonstrates that the prothrombin G20210A mutation jointly influences plasma prothrombin levels and risk of thrombosis

Association studies suggest that the G20210A mutation (G to A substitution at nucleotide position 20210) in the prothrombin gene (PT) is associated with increased plasma prothrombin activity and with increased risk for venous thromboembolism. To test directly for linkage between this PT variant and plasma prothrombin activity we performed a family-based study. The G20210A genotypes and plasma prothrombin activity levels were determined in 435 individuals belonging to 22 extended Spanish families. The sample was composed of 388 homozygous (G/G) normal individuals and 43 heterozygote (G/A) and 4 homozygote (A/A) carriers for the G20210A mutation. The results of variance-component linkage analysis yielded a highly significant lod score of 3.6 (P = 2.4 x 10(-5)) between this mutation and a quantitative trait locus (QTL) that influences prothrombin activity. Importantly, a conditional linkage analysis that simultaneously accounted for association with the G20210A variant completely eliminated the linkage signal, which indicates that this mutation affects the function of the prothrombin gene. Additionally, a bivariate linkage analysis of plasma prothrombin activity and thrombosis significantly improved the linkage signal for prothrombin activity (lod score = 4.7; P = 1.5 x 10(-6)) and provided strong evidence that this QTL has a pleiotropic effect on the risk of thrombosis (lod score = 2.43; P =.0004). These results represent the first direct genetic evidence that a QTL in the PT gene influences prothrombin activity levels and susceptibility to thrombosis and strongly support the conclusion that G20210A is a functional polymorphism. (Blood. 2000;95:2780-2785)

Genetic determinants of hemostasis phenotypes in Spanish families

BACKGROUND

Recent studies have described genetic mutations that affect the risk of thrombosis as a result of abnormal levels of such hemostatic parameters as protein C, protein S, and the activated protein C resistance ratio. Although these mutations suggest that genes play a part in determining variability in some hemostasis-related phenotypes, the relative importance of genetic influences on these traits has not been evaluated.

METHODS AND RESULTS

The relative contributions of genetic and environmental influences to a panel of hemostasis-related phenotypes were assessed in a sample of 397 individuals in 21 extended pedigrees. The effects of measured covariates (sex, age, smoking, and exogenous sex hormones), genes, and environmental variables shared by members of a household were quantified for 27 hemostasis-related measures. All of these phenotypes showed significant genetic contributions, with the majority of heritabilities ranging between 22% and 55% of the residual phenotypic variance after correction for covariate effects. Activated protein C resistance ratio, activated partial thromboplastin time, and Factor XII showed the strongest heritabilities, with 71.3%, 83.0%, and 67.3%, respectively, of the residual phenotypic variation attributable to genetic effects.

CONCLUSIONS

These results clearly demonstrate the importance of genetic factors in determining variation in hemostasis-related phenotypes that are components of the coagulation and fibrinolysis pathways and that have been implicated in risk for thrombosis. The presence of such strong genetic effects suggests that it will be possible to localize previously unknown genes that influence quantitative variation in these hemostasis-related phenotypes that may contribute to risk for thrombosis.

Platelet function during cardiopulmonary bypass not changed by two different doses of aprotinin

BACKGROUND AND OBJECTIVE

Bleeding is one of the major complications of cardiopulmonary bypass (CBP) during cardiac surgery. A platelet function defect seems to be the main cause of the hemostatic problems associated with CBP. Controversial results have been reported concerning the possible protective mechanism of action of aprotinin on platelets.

DESIGN AND METHODS

In this study we investigated the effect of two different dosages of aprotinin (high and pump-prime-only dose) on platelet reactivity in vitro and adhesion, activation and aggregation receptors on the platelet surface.

RESULTS

The results obtained from 53 patients undergoing CBP showed a significantly deficient platelet aggregation in response to agonist in all groups without differences between aprotinin treated or not treated patients. No changes in platelet surface expression of glycoprotein (GP) IIb-IIIa, GPIb, GPIV and P-selectin, were observed during CBP between patients treated with aprotinin or not.

INTERPRETATION AND CONCLUSIONS

These data suggest that inadequate platelet function induced by CBP is not a defect intrinsic to the platelet. We conclude that the hemostatic effect of aprotinin, regardless of the dose employed, is not mediated by protection of platelet function.

Experience with early catheter removal after radical retropubic prostatectomy

PURPOSE

We tested the hypothesis that early catheter removal may be accomplished safely after radical prostatectomy.

MATERIALS AND METHODS

Cystography on postoperative day 4 or 5 in 42 of 67 consecutive patients who underwent radical retropubic prostatectomy revealed no extravasation in 30 and the urethral catheter was removed (group 1). The control group included 25 patients who did not undergo cystography, and the catheter was removed 14 days postoperatively (group 2).

RESULTS

Immediate and late continence was achieved in 14 (46.7%) and 25 (83.3%) cases in group 1, and in 8 (32%) and 22 (88%) cases in group 2, respectively (p>0.05). Catheterization was performed easily without any endoscopic or surgical procedure in 2 patients (6.7%) in group 1 who presented in urinary retention after catheter removal. Wound infection and pelvic abscess developed in 1 case (3.3%). There were no late complications. In group 2 urinary retention developed in 1 patient (4%), wound infection in 1 (4%) and hematuria in 1 (4%). Two patients (8%) had late vesical neck contracture at 4 and 10 months, respectively, which required urethrotomy in 1. In 1 patient (4%) a stricture in the anterior urethra was dilated.

CONCLUSIONS

Our study shows that early catheter removal may be accomplished safely in most patients after radical retropubic prostatectomy, and was not associated with a higher complication rate.

EGF receptor signaling in prostate morphogenesis and tumorigenesis

The growth and differentiation of the prostate gland are largely dependent on extracellular signaling factors. In addition to androgens, many polypeptide growth factors function through autocrine or paracrine networks. The paracrine interaction between stromal and epithelial cells is critical for androgen regulation, morphogenesis, epithelial cell proliferation, and secretory differentiation. Efforts to identify the essential growth factors and studies on their effects have been prompted by the fact that prostate cells in culture need substances other than androgens for proliferation. In this context, transforming growth factor-alpha and epidermal growth factor, among others, have been studied extensively. Recent advances have suggested that these EGF receptor (EGFR) ligands play roles not only during glandular development but also during neoplastic transformation and tumor progression. The cell responses most relevant to the role of this receptor signaling are both mitogenesis and cell motility. The aim of the review is to provide an overview of current knowledge about EGFR and its ligands in the organogenesis and tumorigenesis of the prostate gland.

Homozygotes for prothrombin gene 20210 A allele in a thrombophilic family without clinical manifestations of venous thromboembolism

BACKGROUND AND OBJECTIVE

A new genetic risk factor for venous thromboembolism has recently been described which involves a G to A transition at position 20210 in the 3' untranslated region of the prothrombin gene. To date, only a few homozygotes for this mutation have been reported and in most of cases, they suffered from thrombotic disease. Here, we describe a pedigree including both heterozygous and homozygous subjects for prothrombin (PT) 20210 A.

DESIGN AND METHODS

This family was recruited in 1996 as part of our GAIT (Genetic Analysis of Idiopathic Thrombophilia) project. To qualify for the GAIT study, a pedigree was required to have at least 10 living individuals in three or more generations (i.e. extended pedigree). The pedigrees were selected through probands with idiopathic thrombophilia. A complete set of plasma and DNA determinations related to hemostasis was performed on this family.

RESULTS

The plasma studies yielded normal results in all of the individuals. The family members who had a history of thromboembolism were heterozygous carriers of the PT 20210 A variant. In addition, 4 relatives who were heterozygous, and two who were homozygous for this A allele, failed to show clinical manifestations. These two homozygotes were 51 and 19 years old.

INTERPRETATION AND CONCLUSIONS

This case exemplifies the complexity of thrombotic disease since individuals homozygous for a mutant gene do not exhibit symptoms while heterozygous individuals often do exhibit the disease. This case suggests that the new genetic risk factor for thrombosis (i.e. PT 20210 A) may not be as strong as most of the previously described genetic risk factors.

Elevated levels of plasmin-alpha2 antiplasmin complexes in unstable angina

The evidence of elevated levels of several biochemical markers of prothrombotic state in patients with unstable angina suggests that thrombus formation and lysis play a pivotal role in acute coronary syndromes. The clinical syndrome of unstable angina encompasses a variety of clinical presentations of transient episodes of myocardial ischemia. This study was designed to assess plasmin generation in different settings of unstable angina. Evidence of plasmin generation in patients with unstable angina was measured by circulating plasmin-alpha2 antiplasmin complexes (PAP). A second objective was to identify whether PAP levels had a prognostic value to predict outcome. Eighty-five patients admitted to the coronary care unit for unstable angina were classified into three groups. Group A included 26 patients with postinfarction angina; group B comprised 26 patients with new onset angina; and group C included 33 patients with crescendo angina. Mean PAP levels were higher in the three groups compared to healthy controls. A significant correlation was found between levels of PAP and D-dimer, particularly in postinfarction angina (r = 0.6; p <0.0005). This trial adds new insights into the pathophysiology of unstable angina. It demonstrates that plasmin is generated in the different settings of unstable angina but particularly in postinfarction angina patients where a fibrin-rich thrombus is responsible of the symptoms. However, in this series PAP levels do not predict an uneventful outcome neither in the acute phase nor at long term (6 months).

Lack of association between venous thrombosis and subsequent malignancy in a retrospective cohort study in young patients

Since the publication of Trousseau in 1865, several studies have documented an increased incidence of cancer in patients with deep venous thrombosis (DVT) especially those with idiopathic or recurrent DVT, but in young patients this association is not clear and is therefore a subject of controversy. We performed a retrospective study in a consecutive cohort of 40 young patients (age <40 years) with a DVT and without a known cancer. All patients were diagnosed in our hospital during the period of 1988-1992. At the time of diagnosis, a routine examination to detect the presence of malignant disease was made. For the follow-up, all patients included in the study were asked to return to our unit and were interviewed for symptoms that could suggest a malignant disease. The mean follow-up was five years (from three to eight years). Twenty-four patients had DVT in the lower limbs and three in the upper extremities, nine had pulmonary embolism (six of them with DVT) and four had DVT in other sites. Sixteen patients (40%) had secondary DVT due to nonbiological causes, abnormalities in hemostasis were found in 14 patients (35%), and biological or environmental triggering factors were not identified in 10 patients (25%). Malignancies were not detected at diagnosis and in the follow-up. In our experience, venous-thrombotic patients under the age of 40 have a low incidence of subsequent cancer. Further studies should be performed to confirm this observation and to ascertain whether extensive screening for cancer is a cost-effective approach.

Moderate hyperhomocysteinemia is a highly prevalent defect in Spanish patients with venous thromboembolic disease

Recent studies suggest that mild hyperhomocysteinemia may be a risk factor for venous thromboembolic disease (VTED). In this work we evaluated the prevalence of moderate hyperhomocysteinemia in patients with VTED in our area. We found hyperhomocysteinemia in 23.4% of 64 patients studied compared with 7.35% of 68 healthy controls (p = 0.014). Our results suggest that moderate hyperhomocysteinemia is one of the most prevalent abnormalities associated with VTED.

The prothrombin 20210A allele is the most prevalent genetic risk factor for venous thromboembolism in the Spanish population

We investigated the prevalence of the new recently reported mutation in the prothrombin gene (20210 A) in a sample of 116 unrelated patients with venous thromboembolism. We found 20 heterozygous carriers (17.2%, CI 95% 10.4-21.1). In comparison, we observed 13 carriers among 201 healthy unmatched controls (6.5%, CI 3.5-10.8). The 20210 A mutation seems to increase the risk of venous thrombosis 3-fold (odds ratio 3.1, 95% CI 1.4-6.6). Considering only patients with a first event (n = 62) the OR was 2.0 (p = 0.18, NS) while those with recurrent events (n = 54) showed an OR of 5.9 (95% CI 2.5-14.4). A majority of heterozygous patients (55%) presented a second thrombophilic factor and 60% of affected females had their first event before 30 years of age, while on oral contraceptive treatment. The prevalence found in this study for healthy people is the highest reported to date. The 20210 A variant appears to be the most prevalent genetic risk factor among patients with thrombosis in our geographical area.

Absence of linkage between type III protein S deficiency and the PROS1 and C4BP genes in families carrying the protein S Heerlen allele

To elucidate the molecular basis of hereditary protein S (PS) deficiency and, in particular, type III or free PS deficiency, the allelic distribution and segregation patterns of the PS gene (PROS1) polymorphisms P626A/G and S460P (PS Heerlen) have been analyzed in a group of 45 proposita suffering from type I or type III PS deficiency. No differences between patients and controls were found in the frequency of the P626A/G alleles. By contrast, the frequency of the PS Heerlen allele in the group of patients with type III PS deficiency (9 of 46 chromosomes, P = .196) was significantly higher (P < .001) than in the control group (1 of 300 chromosomes, P = .003). The A allele of P626A/G was always associated with the P allele of S460P. However, this haplotype did not co-segregate with the type III PS-deficient phenotype in 3 of the families. Furthermore, multipoint linkage analysis excluded the whole PROS1 gene in 1 of these families, which is in agreement with the absence of mutations in the PROS1 gene, as determined by sequence analysis. Finally, linkage analysis with 4 microsatellite markers linked to the C4BPB and C4BPA loci also excluded these two genes. From these results we conclude that, at least in some families, the molecular basis of type III PS deficiency is not due to the Mendelian inheritance of a single defect in the PROS1 or in the C4BP genes.

Activated protein C resistance assay when applied in the general population

We estimated the predictive values of activated protein C resistance in the diagnosis of women who are carriers of factor V Leiden. When the prevalence of factor V Leiden is 2%, the positive predictive value is 44% and the cost of preventing one thromboembolic death is $44,180,000. Thus the activated protein C resistance assay is not cost-effective in ruling out factor V Leiden in this population.

Oral surgery in anticoagulated patients without reducing the dose of oral anticoagulant: a prospective randomized study

PURPOSE

This study assessed the risk associated with several schedules of perioperative treatment with coumadin in anticoagulated patients who underwent oral surgery.

PATIENTS AND METHODS

A prospective, randomized study compared bleeding complications with six perioperative schedules in 92 patients chronically treated with acenocoumarol. In three of the perioperative schedules, the dose was reduced before surgery and calcium heparin was added. In the other three, oral anticoagulation was not modified and heparin was not used. The groups also differed regarding the antifibrinolytic agents used and the postoperative measures applied.

RESULTS

Those schedules in which the oral anticoagulation was not modified preoperatively and an antifibrinolytic agent was applied locally both during and after surgery were not associated with a significantly higher odds ratio of bleeding complications than those in whom oral anticoagulation was reduced and calcium heparin was added preoperatively.

CONCLUSIONS

In orally anticoagulated patients who undergo oral surgery, schedules that maintain the oral anticoagulant regimen and use local tranexamic acid as an antifibrinolytic agent postoperatively for 2 days are safe, simple, and less troublesome.

Prothrombotic state and signs of endothelial lesion in plasma of patients with inflammatory bowel disease

Recent investigations suggest that microthrombi formation in bowel capillaries could be a determinant factor in inflammatory bowel disease (IBD) pathogenesis. To evaluate the implication of the hemostatic system during these thrombotic events, we analyzed plasmatic values of prothrombotic state markers, physiologic inhibitors of coagulation, and endothelial lesion markers in 112 IBD patients. We found an increase in thrombin-antithrombin complexes and a decrease in antithrombin III, probably due to consumption, demonstrating an increase in thrombin generation. High levels of D-dimer reflect increased fibrin formation, but there is no correlation between thrombin generation markers and D-dimer, possibly suggesting the presence of inadequate fibrinolysis. Levels of tissue factor pathway inhibitor were higher in patients than in controls. Nine patients with Crohn's disease (35% of our sample) had levels of this marker under 70% (range 37-69%). Von Willebrand factor values were increased and those of thrombomodulin only in active patients. Most of the changes were detected in patients with inflammatory activity, and there were no differences between ulcerative colitis and Crohn's disease. In conclusion, these results support the hypothesis that there is an endothelial lesion with sustained coagulation activation in IBD patients.