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.