Heparin-induced Thrombocytopenia Diagnosis: A Retrospective Study Comparing Heparin-induced Platelet Activation Test to 14 C-serotonin Release Assay.

Laboratory confirmation of heparin-induced thrombocytopenia (HIT) is of crucial importance and remains challenging and relies on platelet functional assays highlighting the presence of heparin-dependent platelet-activating antibodies in patient serum or plasma. Platelet functional assays using washed platelets include the 14 C-serotonin release assay (SRA), usually described as the gold standard, and the heparin-induced platelet activation assay (HIPA). Since its first comparison with SRA there has been no additional published study regarding HIPA diagnostic performances compared with SRA. Aim of our retrospective study was to compare the concordance between HIPA and SRA in HIT suspected-patients with positive anti-PF4/heparin antibodies between October 2010 and October 2015. Fifty-five HIT-suspected patients who beneficiated from both HIPA and SRA were included. Positive and negative percent agreements were 83.8% (95% CI 68.0-93.8%) and 66.7% (95% CI 41.0-86.7%), respectively. Overall percent agreement was 78.2% (95% CI 65.0-92.2%). Agreement was higher in patients who underwent cardiopulmonary bypass with extracorporeal circulation circuit for cardiac surgery. We also confirm that the use of a minimum of 2 platelet donors to establish positive HIT diagnosis and 4 platelet donors to exclude HIT diagnosis allows obtaining a good agreement with SRA. Although HIPA and SRA were performed with different platelet donors and in different laboratories, HIPA had a good positive agreement with SRA for HIT diagnosis, showing that HIPA is a useful functional assay that does not require radioactivity and could be developed worldwide to improve HIT diagnosis.

Heparin-induced thrombocytopenia: Construction of a pretest diagnostic score derived from the analysis of a prospective multinational database, with internal validation.

BACKGROUND: Diagnosis of heparin-induced thrombocytopenia (HIT) requires pretest probability assessment and dedicated laboratory assays. OBJECTIVE: To develop a pretest score for HIT. DESIGN: Observational; analysis of prospectively collected data of hospitalized patients suspected with HIT (ClinicalTrials.gov NCT00748839). SETTING: Thirty-one tertiary hospitals in France, Switzerland, and Belgium. PATIENTS: Patients tested for HIT antibodies (2280 evaluable), randomly allocated to derivation and validation cohorts. MEASUREMENTS: Independent adjudicators diagnosed HIT based on the prospectively collected data and serotonin release assay results. RESULTS: Heparin-induced thrombocytopenia was diagnosed in 234 (14.7%) and 99 (14.5%) patients in the two cohorts. Eight features were associated with HIT (in brackets, points assigned for score calculation of the score): unfractionated heparin (1); therapeutic-dose heparin (1); cardiopulmonary bypass (cardiac surgery) (2); major trauma (3); 5- to 21-day interval from anticoagulation initiation to suspicion of HIT (4); ≥40% decrease in platelet count over ≤6 days (3); thrombotic event, arterial (3) or venous (3). The C-statistic was 0.79 (95% CI, 0.76-0.82). In the validation cohort, the area under the receiver operating characteristic curve was 0.77 (95% CI, 0.74-0.80). Three groups of scores were defined; HIT prevalence reached almost 30% in the high-probability group. LIMITATION: The performance of the score may depend on settings and practices. CONCLUSION: The objective, easy-to-collect, clinical features of HIT we evidenced were incorporated into a pretest score, which may guide clinical decisions regarding diagnostic testing and anticoagulation.

Functional Flow Cytometric Assay for Reliable and Convenient Heparin-Induced Thrombocytopenia Diagnosis in Daily Practice.

Reliable laboratory diagnosis of heparin-induced thrombocytopenia (HIT) remains a major clinical concern. Immunoassays are highly sensitive, while confirmatory functional tests (based on heparin-dependent platelet activation) lack standardization. We evaluated the diagnostic performance of a functional flow cytometric assay (FCA) based on the detection of heparin-dependent platelet activation with an anti-p-selectin. A total of 288 patients were included (131 HIT-positive and 157 HIT-negative) with a HIT diagnosis established by expert opinion adjudication (EOA) considering clinical data and local laboratory results. The FCA was centrally performed in a single laboratory on platelet-rich plasma, using a very simple four-color fluorometer. The results were standardized according to the Heparin Platelet Activation (HEPLA) index. The serotonin release assay (SRA) was performed in the four French reference laboratories. Based on the final HIT diagnosis established by EOA, the sensitivity and specificity of the FCA were 88 and 95%, respectively, values very similar to those of the SRA (88 and 97%, respectively). This study showed that the FCA, based on easily implementable technology, may be routinely used as a reliable confirmatory test for HIT diagnosis.

Novel Splice Site Mutation in the PROS1 Gene in a Polish Patient with Venous Thromboembolism: c.602-2delA, Splice Acceptor Site of Exon 7.

We identified a novel splice site mutation of the PROS1 gene in a Polish family with protein S (PS) deficiency and explored the molecular pathogenesis of this previously undescribed variant. A novel mutation was detected in a 26-year-old woman with a history of venous thromboembolism (VTE) provoked by oral contraceptives. Her family history of VTE was positive. The sequence analysis of the PROS1 gene was performed in the proband and the proband's family. The proband and their asymptomatic father had lower free PS levels (45% and 50%, respectively) and PS activity (48% and 44%, respectively). Total PS levels were normal (65.6% and 62.4%, respectively). The sequence analysis of the PROS1 gene revealed the presence of heterozygous deletion at the nucleotide position c.602-2 in intron 6, just upstream of exon 7, detected in the proband and her father. This variant alters the splice acceptor site of exon 7, and, according to the in silico prediction, it is highly likely to cause in-frame exon 7 skipping. We also presented follow-up data of two other Polish patients with PS deficiency associated with splice site mutations in PROS1 gene.

Genotype-Phenotype Relationships in a Large French Cohort of Subjects with Inherited Protein C Deficiency.

Inherited protein C (PC) deficiency caused by mutations in the PROC gene is a well-known risk factor for venous thromboembolism. Few studies have investigated the relationship between PROC genotype and plasma or clinical phenotypes. We addressed this issue in a large retrospective cohort of 1,115 heterozygous carriers of 226 PROC pathogenic or likely pathogenic mutations. Mutations were classified in three categories according to their observed or presumed association with type I, type IIa, or type IIb PC deficiency. The study population comprised 876 carriers of type I category mutations, 55 carriers of type IIa category mutations, and 184 carriers of type IIb category mutations. PC anticoagulant activity significantly influenced risk of first venous thrombosis (p trend < 10-4). No influence of mutation category on risk of whole or unprovoked thrombotic events was observed. Both PC anticoagulant activity and genotype significantly influenced risk of venous thrombosis. Effect of detrimental mutations on plasma phenotype was ambiguous in several carriers, whatever the mutation category. Altogether, our findings confirm that diagnosing PC inherited deficiency based on plasma measurement may be difficult but show that diagnosis can be improved by PROC genotyping.

Comparative Analysis of a French Prospective Series of 144 Patients with Heparin-Induced Thrombocytopenia (FRIGTIH) and the Literature.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a rare complication of heparin treatments, and only a few large patient cohorts have been reported. In this study, biological and clinical data from 144 French patients with HIT were analyzed in comparison with the literature. METHODS: The diagnosis of HIT was confirmed in all patients by an immunoassay combined with serotonin release assay. In the literature, only cohorts of at least 20 HIT patients published from 1992 were selected for a comparative analysis. RESULTS: Two-thirds of patients were hospitalized in surgery and most were treated with unfractionated heparin (83.2% vs. 16.8% with low molecular weight heparin only). Thrombotic events in 54 patients (39.7%) were mainly venous (41/54). However, arterial thrombosis was more frequent after cardiac surgery (13.2% vs. 2.4% in other surgeries, p = 0.042) with a shorter recovery time (median = 3 vs. 5 days, p < 0.001). The mortality rate was lower in our series than in the 22 selected published studies (median = 6.3% vs. 15.9%). Three genetic polymorphisms were also studied and homozygous subjects FcγRIIA RR were more frequent in patients with thrombosis (37.8 vs. 18.2% in those without thrombosis, p = 0.03). CONCLUSION: This study shows that the mortality rate due to HIT has recently decreased in France, possibly due to earlier diagnosis and improved medical care. It also confirms the strong association between polymorphism FcγRIIA H131R and thrombosis in HIT.

[Deep venous thrombosis treated by rivaroxaban in a young patient with type Ia carbohydrate-deficient glycoprotein (CDG) syndrome]. / Thrombose veineuse profonde traitée par rivaroxaban chez une jeune patiente atteinte de carbohydrate-deficient glycoprotein syndrome de type Ia.

Congenital disorders of glycosylation (CDG) are rare inborn diseases of glycan component of N-glycosylated proteins. We report here the case of a 28-year-old patient with CDG syndrome type Ia, who presented with a deep venous thrombosis in the left suro-popliteal vein with no known triggers or antecedents. The patient was treated with rivaroxaban for six months. Blood tests performed after discontinuing anticoagulant treatment showed multiple abnormalities affecting the proteins involved in haemostasis (both coagulation factors and inhibitors), i.e. a combined factor XI, antithrombin and protein C deficiency (35%, 41%, and 42% respectively) associated with a moderate increase of FVIII (179%) and VWFAg (163%) without inflammation. Patient results are here discussed with regard to the limited number of articles addressing haemostasis in this rare disease, as the occurrence of deep venous thrombosis remains uncommon in the literature.

Genetic characterization of antithrombin, protein C, and protein S deficiencies in Polish patients.

INTRODUCTION    Inherited deficiencies of natural anticoagulants such as antithrombin (AT; gene: SERPINC1), protein C (PC; PROC), and protein S (PS; PROS1), with the prevalence in the general European population of 0.02% to 0.17%, 0.2% to 0.3%, and 0.5%, respectively, are associated with increased risk of thromboembolic events. Only a few case reports of Polish deficient patients with known causal mutations have been published so far. OBJECTIVES    The aim of the study was to characterize the frequency of SERPINC1, PROC, and PROS1 mutations and their thromboembolic manifestations in patients with AT, PC, or PS deficiencies, inhabiting southern Poland. PATIENTS AND METHODS     Ninety unrelated patients (mean [SD] age, 40.1 [13.2] years) with AT (n = 35), PC (n = 28), or PS (n = 27) deficiencies, with a history of venous 73 (81%) or arterial 17 (19%) thromboembolism, were screened for mutations using the Sanger sequencing or multiplex ligation­dependent probe amplification. RESULTS    Twenty mutations (29%) described here were new, mostly in the SERPINC1 and PROC genes. Missense mutations accounted for 84% of all mutations in the PROC gene and approximately 50% of those in the SERPINC1 and PROS1 genes. In all 3 genes, the ratio of nonsense and splice-site mutations was 8% to 31% and 8% to 23%, respectively. The mutation detection rate was 90% for AT or PC when anticoagulant activity was below 70%, while for the PROS1 gene, the rate reached 80% at the free PS levels below 40%. CONCLUSIONS    To our knowledge, this is the largest cohort of Polish patients deficient in natural anticoagulants and evaluated for the causal genetic background. Several new Polish detrimental mutations were detected, mostly in AT- and PC­deficient patients.

Thrombotic risk according to SERPINC1 genotype in a large cohort of subjects with antithrombin inherited deficiency.

Inherited quantitative (type I) or qualitative (type II) antithrombin deficiency (ATD) due to mutations in the SERPINC1 gene is a well-known risk factor for venous thromboembolism. ATD may also increase risk for arterial thrombosis. Few studies have investigated risk for thrombosis according to mutations. We addressed this topic in a large retrospective cohort study of 540 heterozygous carriers of SERPINC1 mutations and compared risk for first venous or arterial thrombosis associated with carrying of different type II or type I mutations. No clear difference in risk for first venous thrombotic event was observed among type I (missense or null), type IIRS or type IIPE mutation carriers except for a few variants that displayed lower risk [all events, adjusted relative risk: Cambridge II: 0.42 (95 %CI 0.25-0.70), Dublin: 0.35 (95 %CI 0.13-0.99)]. IIHBS mutation carrying was associated with a clearly lower risk than type I mutation carrying [0.28 (95 %CI 0.20-0.40)]. These differences in risk were observed for both all venous thrombotic events and pulmonary embolism associated with deep venous thrombosis. The HBS group was also heterogeneous, with AT Budapest 3 carriers displaying a non-significantly different risk [0.61 (95 %CI 0.31-1.20)] compared to type I mutation carriers. We also studied risk for arterial thrombosis and found no significant influence of mutation type. Altogether, our findings suggest a place for SERPINC1 genotyping in the diagnosis of ATD.

Sex hormone-binding globulin and thrombin generation in women using hormonal contraception.

OBJECTIVES: We investigated the impact of serum sex hormone-binding globulin (SHBG) on thrombin generation (TG) in women according to hormonal contraception. PATIENTS AND METHODS: A cross-sectional study of SHBG and TG measured via calibrated automated thrombography was conducted in 150 healthy women, including 75 users of combined oral contraceptives (COC), 22 users of progestin-only contraceptives (POC) and 53 nonusers. RESULTS: COC but not POC-users had significantly higher SHBG levels compared with nonusers. In hormonal contraceptive users, SHBG was positively associated with both activated protein C (APC) resistance and baseline TG, and protein S and prothrombin were important mediators. CONCLUSION: These data provide further evidence that SHBG may be used as a biomarker in assessing prothrombotic profile of hormonal contraception.

Venous thromboembolism associated with protein S deficiency due to Arg451* mutation in PROS1 gene: a case report and a literature review.

Protein S (PS) is a vitaminK-dependent glycoproteinwhich plays an important role in the regulation of blood coagulation. PS deficiency has been found in 1.5-7% of thrombophilic patients. Here, we report the first Polish case with PS deficiency caused by the p.Arg451* in the PROS1 gene detected in a 21-year-old man with trauma-induced venous thromboembolism. To our knowledge, we provided the review of all the available data on this mutation (a total of 56 cases). The proband, his mother and his sister were screened for thrombophilia. To elucidate genetic background of PS deficiency, all PROS1 genes were subjected to direct sequencing. The free PS levels were 35% in the proband, 21% in the proband's mother and 28% in the proband's sister and their PS total levels were 37.1, 47.5 and 55.1%, respectively. Type I PS deficiency was diagnosed. In all patients, genetic analysis revealed the presence of heterozygous nonsense mutation (c.1351C>T; p.Arg451*) located in exon 12 of PROS1 gene. This mutation interrupts the reading frame by premature termination codon at position 451 and may lead to the production of truncated protein. The present case combined with the review of the literature suggests that p.Arg451* in the PROS1 gene mainly leads to clinically evident thrombosis following trauma, surgery or serious comorbidities especially malignancy.

Presentation, management and outcome of heparin-induced thrombocytopenia after valvular heart surgery.

OBJECTIVES: The use of heparin exposes patients to heparin-induced thrombocytopenia, which is a challenging issue for both diagnosis and patient management. We sought to describe the clinical presentation, management and outcome of a series of patients diagnosed with heparin-induced thrombocytopenia after heart valve surgery. METHODS: All consecutive patients diagnosed with heparin-induced thrombocytopenia during the postoperative period of heart valve surgery over a 6-year period were prospectively enrolled in a single-centre registry. Clinical and biological data were collected. In-hospital and mid-term outcomes were assessed. Information regarding the occurrence of all medical events including death, recurrence of thromboembolic events and/or thrombocytopenia was collected. RESULTS: We identified 93 patients (incidence proportion = 2.8%). Most patients (82%) were asymptomatic with isolated thrombocytopenia at the time of diagnosis. The other main circumstance of diagnosis was the occurrence of thromboembolic events in 17 patients (6 strokes, 10 prosthetic valve thrombosis and 1 peripheral embolic event). The in-hospital mortality rate was 1%. No thrombolysis, interventional procedure or redo surgery was performed. Danaparoid sodium was used as heparin replacement therapy in most cases (96%) and leading to complete and uneventful thrombus resolution in all cases with only one possibly related major bleeding complication. During a mean follow-up of 36 ± 20 months, no patient presented recurrence of any heparin-induced thrombocytopenia-related complication. CONCLUSIONS: In this contemporary series of patients, heparin-induced thrombocytopenia incidence was low and isolated thrombocytopenia was the most frequent presentation. Conservative management with early diagnosis and substitutive anticoagulation therapy introduction was associated with a low rate of clinical events and a remarkably good outcome with a low mortality rate.

Rosuvastatin Is Effective to Decrease CD8 T-Cell Activation Only in HIV-Infected Patients With High Residual T-Cell Activation Under Antiretroviral Therapy.

OBJECTIVE: The aim of the trial was to evaluate in patients under antiretroviral therapy (ART) the effect of rosuvastatin on cellular and soluble markers of immune activation/inflammation, as well as to identify patients who better benefit from statin administration. METHODS: IMEA-043-CESAR was a phase II open-label pilot trial that enrolled patients under suppressive ART and CD4 <500/mm. Patients received rosuvastatin (20 mg/d) for 12 weeks. The primary outcome was the variation at week 12 (W12) in the proportion of CD38HLA-DRCD8 T lymphocytes. Secondary outcomes included evolution of other markers of T-cell activation and of inflammatory biomarkers between baseline, W12, and W24. RESULTS: Fifty patients were enrolled; end points were available for 43 patients. When considering all patients, the proportion of CD38HLA-DRCD8 T cells did not significantly decline throughout the follow-up. However, the proportion of CD38CD8T cells significantly decreased at W12 [median percentage change of -22.2% (-32.3; +1.4)]. Principal component analysis allowed identification of 3 groups of patients based on their baseline activation/inflammation profiles, 1 group with elevated levels of CD8 T-cell activation, and a small group with high levels of systemic inflammation and low levels of T-cell activation. Half of the patients exhibited relatively low levels of inflammation and activation. The proportion of activated CD8 T cells significantly decreased only in the particular group of patients with high baseline CD8 T-cell activation. CONCLUSIONS: This study shows that combining rosuvastatin with effective ART can result in a sustained decrease in CD8 T-cell activation and highlights the importance of identifying patients who can benefit from specific immunotherapeutic strategies.

PROS1 genotype phenotype relationships in a large cohort of adults with suspicion of inherited quantitative protein S deficiency.

Inherited protein S deficiency (PSD) is an established risk factor for venous thromboembolism (VTE). However, data are conflicting concerning risk of VTE associated with decreased free PS level (FPS) and information on PROS1 genotype-phenotype relationship is sparse. In a retrospective cohort of 579 patients with inherited type I/III deficiency suspicion, PROS1 genotyping was performed and the effect of genotype on FPS and on VTE risk was investigated. We found 116 (including 65 novel) detrimental mutations (DM) in 222 (type I/III in 194, type II in 28), PS Heerlen in 74, possibly non DM in 38 and no mutation in 245 subjects. Among DMs, type I/IIIDMs only were found in subjects with FPS< 30 %. Prevalence of type I/III DM decreased with increasing FPS level. Risk of VT associated with FPS level and genotype was studied in the 467 subjects with personal or family history of thrombosis. Only type I/IIIDM carriers presented with an increased risk of VTE [1.41 (95 %CI (1.05-1.89)] compared to subjects with no mutation. Among the group of type I/IIIDM heterozygotes and subjects with no mutation, the optimal FPS cut-off point for identifying subjects at increased VTE risk was searched for. We found that only subjects with FPS< 30 % and type I/IIIDM presented with an increased risk [1.48 (95 %CI 1.08-2.04)]. Our findings confirm the value of a cut-off FPS level for identifying subjects at increased VTE risk far below the lower limit of the normal range and suggest a place for PROS1 genotyping in PSD diagnosis strategy.

Role of protein S deficiency in children with venous thromboembolism. An observational international cohort study.

Venous thromboembolism [TE] is a multifactorial disease, and protein S deficiency [PSD] constitutes a major risk factor. In the present study the prevalence of PSD and the clinical presentation at TE onset in a cohort of children is reported. In 367 unselected paediatric patients with TE (age 0.1-18 years) recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. Thirty of 367 paediatric patients (8.2 %) derived from 27 families had PSD. Mean age at first TE onset was 14.5 years (range 0.1 to 18). Thrombotic locations were cerebral veins (n=8), calf vein TE (n=3) deep veins (DVT) of the leg (n=12), DVT & pulmonary embolism (n=5) and intra-cardiac veins (n=1) or purpura fulminans (n=1). PSD co-occurred with the factor 5 mutation at rs6025 or the homozygous factor 2 susceptibility variant at rs1799963 in one case each. The Heerlen polymorphism detected in five children presented with milder PSD. In 18 patients (60 %) a concomitant risk factor for TE was identified. A second TE event within primarily healthy siblings occurred in three of 27 PSD families (11.0 %). In this cohort of children with symptomatic TE, the prevalence of PSD adjusted for family status was 7.4 %. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high-risk population.

Antithrombin Katowice: exon 1 deletion in the SERPINC1 gene associated with type I antithrombin deficiency.

Type I antithrombin deficiency is an autosomal dominant disorder associated with thromboembolic complications mainly related to single-point mutations in SERPINC1, the gene encoding antithrombin. Chromosomal rearrangements have been found in up to 10% of cases with type I antithrombin deficiency. We report here the first heterozygous deletion of SERPINC1 exon 1 identified in a 44-year-old man with type I deficiency who developed deep vein thrombosis of the left leg complicated by pulmonary embolism. This study demonstrates that the search for large gene rearrangements in SERPINC1 can be a useful diagnostic approach, particularly in patients with type I antithrombin deficiency without mutations in SERPINC1.

Clinical and laboratory characteristics of children with venous thromboembolism and protein C-deficiency: an observational Israeli-German cohort study.

Venous thromboembolism [TE] is a multifactorial disease and protein C deficiency [PCD] constitutes a major risk factor. In the present study the prevalence of PCD and the clinical presentation at TE onset, including neonatal purpura fulminans, in a cohort of children are reported. In 367 unselected children (0·1-19 years) recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. Twenty-five of 338 children (7·4%) had PCD. Mean age at first TE onset was 10 years (range 0·1-18). Leading thromboembolic manifestations were neonatal purpura fulminans (n = 5), TE of cerebral veins (n = 3), stroke (n = 2) deep veinthrombosis (DVT) of the leg (n = 10), DVT & pulmonary embolism (n = 2) and DVT & pelvic veins (n = 3). Concomitant risk factors for TE were identified in 12 patients, whereas 13 children spontaneously developed TE. A positive family history of DVT was found in 10 children. In this unselected cohort of paediatric patients with symptomatic TE the overall prevalence of PCD was 7·4%; 1·5% presented with neonatal purpura fulminans. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high-risk population.

[Stability of coagulation parameters: review of available data]. / Stabilité pré-analytique des paramètres de la coagulation : revue des données disponibles.

Samples for hemostasis testing are vulnerable to the effects of preanalytical variables and quality standards for sample processing and storage must be defined to insure accurate results. This article presents the available informations on these preanalytical issues.