High Altitude: A Hyper Coagulable State: Results of a Prospective Cohort Study.

Abstract Thrombosis has been recognized as a complication of rapid ascent as well as long-term stay at high altitude (HA). Researchers have presented conflicting results and majority of them studied only short-term stay. A prospective cohort study was carried out at a height of 3500 m to study the hematological factors, which may lead to increased propensity to thrombosis on prolonged stay at HA. The subjects were healthy low landers (initial N=38, complete follow up N=32) in age group of 20–40 years, inducted to HA and investigated at induction and subsequently at 3 and 8 months. The comparison cohort was age and sex matched low landers not inducted to HA. Bleeding time, clotting time, hemoglobin (Hb), HCT, platelet count, prothrombin time, APTT, fibrinogen, d-dimers. Protein C, protein S, anti-thrombin III levels, APC resistance, PAI-1, Beta thromboglobulin (BTG) and PF4 were estimated. On induction to HA the mean Hb, platelet count, fibrinogen levels, PAI-1 levels and levels of platelet activation factors were in normal range and not statistically different from those at low altitude (P>0.05). None of the subjects had thrombophilia. There was no statistically significant change in Protein C, Protein S, AT III levels, APC resistance, BT, CT, PT and APTT. The mean values were: Hb (13.9, 15.6, 16.6 gm/dl); platelet count (255, 309, 343 x 103/mm3); fibrinogen (253, 304, 346 mg/dl); BTG (30.3, 38.5, 47.3 IU/ml); PF 4 (3.9, 7.6, 13.7 IU/ml) and; PAI-1 (23.7, 40.1, 49.3 ng/ml), at (induction, 3 months, 8 months) respectively. The P value for all was 0.000 by repeated measure analysis. The high Hb itself is unlikely to be the single cause of the thrombotic tendency at HA as its maximum value was 18.0 gm/dl. Erythrocytosis and hyper viscosity are known to activate platelets, however, platelet activation may be the result of hypoxic stress and injury to platelets or endothelium. An important finding of the study was the rise in PAI-1 levels that correlated with rise in fibrinogen levels and duration of stay at HA (Figure 1 and 2). The endothelial injury and clotting activation followed by increased fibrinolysis maintains homeostasis. We hypothesize that increased PAI-1 level tilts the balance by decreasing fibrinolytic activity and increasing propensity to thrombosis. Hypoxia during surgery is known to cause raised postoperative PAI-1 levels leading to a tendency of postoperative thrombosis. The prolonged hypoxia in a lowlander staying in HA may have a similar effect. By virtue of increased platelet count, hematocrit, platelet activation factors, PAI-1 and fibrinogen, prolonged stay at HA is a pro thrombotic state. Thus, there may be a role for antiplatelet drugs in prevention in view of the platelet hyperactivity and interventional trials with homocysteine lowering vitamins or aspirin also need to be considered.

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Possible Risk Factors of Thrombosis in Chinese Patients with Paroxysmal Nocturnal Hemoglobinuria

Blood ◽

10.1182/blood.v128.22.2427.2427 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2427-2427

Author(s):

Zhangbiao Long ◽

Yali Du ◽

Hongmin Li ◽

Zhao Wang ◽

Bing Han

Keyword(s):

Risk Factors ◽

Platelet Count ◽

Protein C ◽

Paroxysmal Nocturnal Hemoglobinuria ◽

Antithrombin Iii ◽

Thrombus Formation ◽

Protein S ◽

Reticular Cell ◽

C Protein ◽

Apc Resistance

Abstract Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease caused by an acquired mutation of the X-linked PIGA gene on the hematopoietic stem cell. Thrombosis is one of the most common causes of mortality in PNH, but the predisposing factors for thrombosis are yet to be defined. In this study, we outline the clinical characters of thrombotic PNH and detect the susceptible genes which may lead to thrombotic formation. Methods: There were totally 94 patients with PNH diagnosed between 2011 and 2015 enrolled in the study. Clinical data like sex, age, hemoglobin level, reticular cell percentage, white blood cell and platelet count, LDH level, CD59- and FLAER granulocytes percentage, thrombophilia risk factors like level of protein C, protein S, antithrombin III, APC resistance, blood fat, phospholipid antibody were evaluated. Samples from patients were genotyped for the reported 33 alleles in 21 genes including MTHFR, PROC, PROS, F2, F5, ABO, prothrombin and other genes which are reported as high risk factors for venous thromboembolism (VTE) by polymerase chain reaction fragment length polymorphism methods (PCR-RFLP). Furthermore, we detected plasma VIII factor and vWF levels which were affect by ABO polymorphism. Results:Of the 94 PNH patients, 16 (17%) patients had at least 1 episode of thrombotic event. Only 2 patients had arterial thrombosis and 14 patients had venous thrombosis. The medium age of patients with thrombosis was 42-year old, similar to those without (43-year-old, p=0.199). Male : female ratio was 1.29 in thrombosis group and 1.16 in non-thrombosis group (p=1.000). Although there was no difference in level of hemoglobin, white blood cell count, platelet count, reticular cell count, LDH, protein C, protein S, antithrombin III, APC resistance, blood fat, phospholipid antibody level (p>0.05) between patients with thrombosis and those without, the percentage of CD59- erythrocytes( p=0.001 ), CD59- granulocytes ( p=0.004 ) and FLAER- granulocytes (p=0.003) was higher in thrombotic patients. Patients with the TT genotype (rs495828 in the ABO gene) were approximately 3.03 folds prone to thrombus formation than those with the GG genotype (p=0.0204 ), and patients with the TC genotype (rs2519093 in the ABO gene) were approximately 4.24 folds prone to thrombus formation than those with the CC genotype ( p=0.0352 ). In addition, minor allele frequencies of rs495828 or rs2519093 and CD59- erythrocytes were independent risk factor for thrombosis in PNH patients. No association was detected between other SNPs and risk to thrombosis. There was no difference in level of vWF-Ag (156% vs 152%, p=0.870) and VIII factor (190% vs 156%, p=0.198) between patients with or without thrombosis, although the level was much higher in PNH patients than normal controls (178% vs 107%, p=0.005 and 203% vs 128%, p=0.003 respectively). Conclusion: Compared with non-thrombotic patients, thrombotic PNH patients have have bigger PNH clone. And for the first time, our results suggested that the rs495828/rs2519093 in the ABO gene confers risk to thrombosis in PNH. Therefore, rs495828/rs2519093 polymorphism may represent a potential genetic biomarker in PNH patients for thrombus formation. Disclosures No relevant conflicts of interest to declare.

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Thrombophilia Testing in Hospitalized Children: Waste Not, Want Not?

Blood ◽

10.1182/blood.v120.21.1150.1150 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1150-1150

Author(s):

Arash Mahajerin ◽

Terry Vik ◽

Rakesh P Mehta ◽

Mark Heiny

Keyword(s):

Risk Factors ◽

Protein C ◽

Protein S ◽

Hospital Charges ◽

Hospitalized Children ◽

Cost Burden ◽

C Protein ◽

Medicaid Reimbursement ◽

Thrombophilia Testing ◽

Pai 1

Abstract Abstract 1150 Introduction The incidence of venous thromboembolism (VTE) in children is rising. Our institutional experience has shown VTE incidence in hospitalized children rose from 0.3 to 71/10,000 admissions over a 13 year span. Many of these children had multiple acquired risk factors, e.g. central venous line (CVL), and many of these children underwent extensive thrombophilia testing. Hypothesis: Thrombophilia testing in hospitalized children with VTE is unnecessary and adds cost burden to patient (pt) care. Methods We evaluated thrombophilia testing performed in children aged 0–20 admitted to Riley Hospital for Children from Jan 2005-Apr 2012. Eligibility criteria included admission for > 48 hours with no clinical suspicion of VTE on admit and subsequent VTE confirmed by ultrasound, CT or MRI. We evaluated for presence of 8 acquired risk factors identified a priori and known to be significant at our hospital: BMI > 85th %ile for age/gender, length of stay > 7 days, mechanical ventilation, direct ICU admit, bacteremia, immobilization > 72 hours, estrogen therapy, and CVL presence (Sharathkumar et al J Thromb Haemost 2012). Thrombophilia testing included Protein C, Protein S, and Antithrombin activities, antiphospholipid antibody panel (APLA, including anti-phosphatidylserine, anti-cardiolipin and lupus anticoagulant), β2 glycoprotein 1 (β2GP1) Ab, presence of Factor V Leiden (FVL) and prothrombin 20210A gene (PTm) mutations, PAI-1 and MTHFR gene (A1298C & C677T) polymorphisms. A thrombophilic condition was diagnosed if a low Protein C, Protein S, or Antithrombin activity was found initially and confirmed after VTE resolution, if APLA or β2GP1 Ab was positive at diagnosis and again after > 12 weeks, hetero- or homozygosity for FVL or PTm, 4G/5G or 4G/4G PAI-1 status with elevated PAI-1 serum level, or MTHFR mutation with elevated fasting AM homocysteinelevel. Cost of thrombophilia testing was evaluated with hospital charges and Medicaid reimbursement rates. Results VTE was diagnosed in 239 patients. At least 1 risk factor was found in 232 (97%) patients and 7 (3%) had no risk factors. These 7 patients with no risk factors had thrombophilia tests done and none had a positive test. Presence of a CVL was significantly associated with nothaving any tests done (p<0.0022). At least 1 thrombophilia test was ordered on 157/239 patients (66%). There were 940 total tests ordered (6 tests/pt) and only 16 positive results (1.7%). Eleven patients were FVL heterozygous and 1 patient was FVL homozygous yielding FVL prevalence of 7.6%. Four patients were PTm heterozygous yielding PTm prevalence of 2.5%. This is similar to prevalence of FVL (5–7%) and PTm (3%) in healthy populations (Martinelli J Thromb Haemost2001). Table 1 shows thrombophilia testing distribution. Cost analysis shows average Medicaid reimbursement of 32.7% of charges billed. Medicaid cost savings of up to $365.25/ptcan be attained by eliminating routine thrombophilia testing in hospitalized children who develop VTE. Discussion The incidence of VTE in hospitalized children is increasing. Many hospitalized children who develop VTE undergo thrombophilia testing. With increased survival of children with chronic diseases and increased prevalence of acquired VTE risk factors, thrombophilia testing in hospitalized children is not necessary and adds cost burden. Thrombophilia testing in children may best be limited to spontaneous VTE. This evaluation is somewhat limited by the low number of subjects with APLA, PAI-1 serum activity or homocysteine labs. Also, we did not include other risk factors, e.g. family history. However, recent ACCP guidelines recommend anticoagulation duration not be adjusted for presence of thrombophilia. There is also concern Medicaid may not reimburse for inpatient VTE in children in the future. Considering we found no difference between hospitalized children with VTE and healthy populations along with current and future financial concerns, we support not testing for thrombophilia in hospitalized children who develop VTE. Disclosures: No relevant conflicts of interest to declare.

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Naturally Occurring Anticoagulants and Their Association With Thromboembolism In Patients With β-Thalassemia Major

Blood ◽

10.1182/blood.v122.21.4792.4792 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4792-4792

Author(s):

Sadia Sultan ◽

Syed Mohammed Irfan ◽

Rozina Zeeshan

Keyword(s):

Protein C ◽

Complete Blood Count ◽

Conflicts Of Interest ◽

Protein S ◽

Thrombotic Risk ◽

C Protein ◽

Positive Correlation ◽

The Mean ◽

And Control

Introduction Hypercoagulopathy and thromboembolic manifestations are being increasing acknowledged in transfusion dependent thalassemics; both intermedia and major. Studies in preceding decade have shown that hemostatic alterations including natural anticoagulant deficiency obligate thalassemic for thromboembolism. The aim of our study is to determine the status of natural anticoagulants and their association with thromboembolism during follow up. Method This is a prospective case-control study, during which 40 cases and 30 controls were registered between Jan 2009 to Dec 2009. Complete blood count, protein C, protein S, antithrombin, serum ferritin, liver function test; HbsAg and Anti HCV were determined. Patients were followed till 30th June 2012 for thromboembolic disease. Data was entered and analyzed using SPSS version 17. The results were expressed as mean ± SD for quantitative variables and qualitative variables are presented as frequency & percentages. Student‘t’ test was applied for the comparison of means. We also computed spearman correlation at 5% level of significance to identify relationship between the deficiency of natural anticoagulants with maternal characteristics, hematological parameters and biochemical markers. Chi- square test was applied for correlation of prothrombotic markers with hepatitis B & C. Results The mean age of patients and control was 12.30±5.5 and 13.39±4.5 years respectively. There were 21 males and 19 females in patient group. The mean protein C, protein S and antithrombin in patients and control were 58.25±22.5 versus 110.67±22.60 (P<0.001), 67.90±19.58 versus 98.70±21.54 and 89.73±18.09 versus 104.0±10.98 (P<0.001) respectively. Protein C was exceedingly deficient in 65% followed by protein S & antithrombin in 35% and 20% respectively. Protein S deficiency revealed positive correlation with protein C deficiency and hemoglobin ≤ 8 gm% was correlated with antithrombin deficiency(P<0.05). No positive correlation of prothrombotic markers were established with others parameters evaluated. Till June 2012, 7 patients were lost to follow up and 2 died owing to cardiac failure. Of the 31 patients in regular follow up none has experienced thromboembolism both clinically and radiologically. Conclusion Decremented prothrombotic markers, primarily protein C, are implicated in elevated thrombotic risk in TM patients. However we did not encounter thromboembolism in our patients during follow up. We recommend prothrombotic screening and prophylactic anticoagulation in high risk group: bed bound splenectomized, cardiopulmonary complications and post operative. Disclosures: No relevant conflicts of interest to declare.

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Coagulation and Fibrinolysis Indicators and Placental Malaria Infection in an Area Characterized by Unstable Malaria Transmission in Central Sudan

Malaria Research and Treatment ◽

10.1155/2015/369237 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Amged G. Mostafa ◽

Naser E. Bilal ◽

Awad-Elkareem Abass ◽

Elhassan M. Elhassan ◽

Ahmed A. Mohmmed ◽

...

Keyword(s):

Malaria Infection ◽

Protein C ◽

Antithrombin Iii ◽

Histopathological Examination ◽

Placental Malaria ◽

Protein S ◽

C Protein ◽

Significant Difference ◽

Pai 1 ◽

Coagulation And Fibrinolysis

This study aimed to investigate coagulation, fibrinolysis indicators, and malaria during pregnancy. Methods. A cross-sectional study was conducted at Medani, Sudan. Sociodemographic characteristics were gathered from each parturient woman (163) and malaria was investigated by blood film and placental histology. Protein C, protein S, antithrombin-III, tissue factor pathway inhibitor (TFPI), and plasminogen activator inhibitor-1 levels (PAI-1) were measured using ELISA. Results. One (0.6%), three (1.8), and 19 (11.7%) of the placentae showed active, chronic, and past infection on a histopathological examination, respectively, while 140 (85.9%) of them showed no signs of malaria infection. While the mean [SD] of the protein C, antithrombin-III, and TFPI was significantly lower, there was no significant difference in protein S and PAI-1 levels in women with placental malaria infection (n=23) compared to those without placental malaria infection (140). In linear regression, placental malaria infection was associated with antithrombin-III. There was no association between placental malaria infections and protein C, protein S, TFPI, and PAI-1 levels. There was no association between hemoglobin, birth weight, and the investigated coagulation and fibrinolysis indicators. Conclusion. This study showed significantly lower levels of protein C, antithrombin-III, and TFPI in women with placental malaria infections.

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Improved Detection of FV Leiden Patients Using a Novel Snake-Venom-Based Activated Protein C Resistance Assay.

Blood ◽

10.1182/blood.v104.11.1058.1058 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1058-1058

Author(s):

Marianne Wilmer ◽

Christoph Stocker ◽

Beatrice Buehler ◽

Brigitte Conell ◽

Andreas Calatzis

Keyword(s):

Snake Venom ◽

Lupus Anticoagulant ◽

Protein C ◽

Activated Protein C ◽

Factor V Leiden ◽

Protein S ◽

Factor V ◽

C Protein ◽

Apc Resistance ◽

Thrombophilia Screening

Abstract A new functional prothrombin-based activated protein C (APC) resistance (APC-R) test (Pefakit® APC-R Factor V Leiden, Pentapharm, Basel, Switzerland) is presented. Methods: The plasma sample is mixed with a reagent containing APC and snake venom specifically activating FV (RVV-V, Daboia russelli) and plasma that has been depleted of FV. During an incubation period of 180 sec the activated FV is inactivated by APC. Subsequently a reagent that contains a FV dependent prothrombin activator (Noscarin, Notechis scutatus) and EDTA is added. The clotting time is recorded. A second determination is performed under identical conditions, with the exception that no APC is added to the first reagent. A ratio between the two measurements is calculated. 703 samples of patients undergoing thrombophilia screening were analysed. Results were correlated to PCR based FVL testing, aPTT, PT, and to levels of Protein C, Protein S, Fibrinogen, FVIII and lupus anticoagulant index. Results: Using a predefined cut-off of a ratio of 2.5 a 100% sensitivity and specificity for the detection of a FVL mutation was found. Using a cut-off ratio of 1.2 a complete but narrow distinction of FVL heterozygous (n=192) and FVL homozygous samples (n=27) was determined. No interference by sample’s INR and aPTT, PS, fibrinogen and FVIII levels and lupus anticoagulant ratio was detected. Conclusion: The new snake-venom-based APC-R assay provides an improved distinction of FV wild-type and FVL carriers compared to the data reported for the aPTT based methods. The use of a FV dependent prothrombin activator eliminates effects of FVIII concentration or lupus anticoagulants in the sample.

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Influence of L-asparaginase on fibrinogen, antithrombin III, protein C, protein S, Von Willebrand factor, PAI 1 and β-TG

Fibrinolysis and Proteolysis ◽

10.1016/0268-9499(94)90668-8 ◽

1994 ◽

Vol 8 ◽

pp. 136

Author(s):

U. Nowak-Göttl ◽

B. Kehrel ◽

J. Wolff ◽

J. Boos ◽

H. Jürgens

Keyword(s):

Von Willebrand Factor ◽

Protein C ◽

Antithrombin Iii ◽

Protein S ◽

C Protein ◽

Von Willebrand ◽

Willebrand Factor ◽

Pai 1

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Activated Protein C Increases Fibrin Clot Lysis by Neutralization of Plasminogen Activator Inhibitor No Evidence for a Cofactor Role of Protein S

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647055 ◽

1988 ◽

Vol 60 (02) ◽

pp. 328-333 ◽

Cited By ~ 44

Author(s):

N J de Fouw ◽

Y F de Jong ◽

F Haverkate ◽

R M Bertina

Keyword(s):

Plasminogen Activator ◽

Protein C ◽

Blood Platelets ◽

Plasminogen Activator Inhibitor ◽

Protein S ◽

Tissue Type ◽

Clot Lysis ◽

Activator Inhibitor ◽

Pai 1

summaryThe effect of purified human activated protein G (APC) on fibrinolysis was studied using a clot iysis system consisting of purified glu-plasminogen, tissue-type plasminogen activator, plasminogen activator inhibitor (released from endothelial cells or blood platelets), fibrinogen, 125T-fibrinogen and thrombin. All proteins were of human origin.In this system APC could increase fibrinolysis in a dose dependent way, without affecting fibrin formation or fibrin crosslinking. However, this profibrinolytic effect of APC could only be observed when plasminogen activator inhibitor (PAI-l) was present. The effect of APC was completely quenched by pretreatment of APC with anti-protein C IgG or di-isopropylfluorophosphate. Addition of the cofactors of APC:protein S, Ca2+-ions and phospholipid-alone or in combination did not enhance the profibrinolytic effect of APC. These observations indicate that human APC can accelerate in vitro clot lysis by the inactivation of PAI-1 activity. However, the neutralization of PAI-1 by APC is independent of the presence or absence of protein S, phospholipid and Ca2+-ions.

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Elevated Levels of Prothrombin Activation Fragment 1+2 in Plasma from Patients with Heterozygous Arg506 to Gin Mutation in the Factor V Gene (APC-Resistance) and/or Inherited Protein S Deficiency

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650259 ◽

1996 ◽

Vol 75 (02) ◽

pp. 270-274 ◽

Cited By ~ 57

Author(s):

Benget Zöller ◽

Johan Holm ◽

Peter Svensson ◽

Björn Dahlbäck

Keyword(s):

Plasma Concentration ◽

Protein C ◽

Protein S ◽

Factor V ◽

Protein S Deficiency ◽

Apc Resistance ◽

S Deficiency ◽

Increased Risk ◽

Factor V Gene ◽

V Gene

SummaryInherited resistance to activated protein C (APC-resistance), caused by a point mutation in the factor V gene leading to replacement of Arg(R)506 with a Gin (Q), and inherited protein S deficiency are associated with functional impairment of the protein C anticoagulant system, yielding lifelong hypercoagulability and increased risk of thrombosis. APC-resistance is often an additional genetic risk factor in thrombosis-prone protein S deficient families. The plasma concentration of prothrombin fragment 1+2 (F1+2), which is a marker of hyper-coagulable states, was measured in 205 members of 34 thrombosis-prone families harbouring the Arg506 to Gin mutation (APC-resistance) and/or inherited protein S deficiency. The plasma concentration of F1+2 was significantly higher both in 38 individuals carrying the FV:Q506 mutation in heterozygous state (1.7 ± 0.7 nM; mean ± SD) and in 48 protein S deficient cases (1.9 ± 0.9 nM), than in 100 unaffected relatives (1.3 ±0.5 nM). Warfarin therapy decreased the F1+2 levels, even in those four patients who had combined defects (0.5 ± 0.3 nM). Our results agree with the hypothesis that individuals with APC-resistance or protein S deficiency have an imbalance between pro- and anti-coagulant forces leading to increased thrombin generation and a hypercoagulable state.

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