RECOMBINANT SINGLE CHAIN VARIABLE FRAGMENT ANTIBODIES (scFv) AGAINST Pro144-Leu155 FRAGMENT OF HUMAN PROTEIN C

The aim of this work was to obtain the recombinant single chain variable fragments of antibodies (scFv) against human protein C, the key component of blood anticoagulation system. For this purpose a peptide that mimics a Pro144-Leu155 sequence of protein C was synthesized and the murine immune scFv library against this peptide was constructed. The protein C specific scFv 9E were selected from the constructed library by the phage-display method. The scFv 9E dissociation constant was found to be 2∙10(-9) M. It was shown that scFv 9E were suitable for protein C detection by ELISA and Western blotting. Selected scFv could be further used for protein C investigation and for the development of quantitative methods for protein C detection in human blood.

Comparative study of the effects of combined oral contraceptives in hemostatic variables: an observational preliminary study

Thrombotic risk is associated with the estrogen dose and type of progestin in combined oral contraceptives. Studies published since 1990 showed that third-generation progestins have larger risk to contribute to thrombosis development than the second-generation. However, there are conflicts in the literature regarding the thrombotic risk associated to the drospirenone progestin. So, this study aimed to evaluate the effects of 3 formulations of contraceptives containing ethinylestradiol (EE) (20 and 30 μg) combined with drospirenone versus levonorgestrel combined with EE (30 μg) in hemostatic parameters. This cross-sectional study included 70 healthy women between 18 and 30 years, BMI 19 to 30 kg/m², not pregnant, non-smokers, and users or non-users (control) of contraceptives for a minimum period of 6 months. The following parameters were assessed: prothrombin time (PT), Factor VII, activated partial thromboplastin time (aPTT), Factor XII, fibrinogen, Factor 1 + 2, Protein C, Protein S, antithrombin, D-dimers, and plasminogen activator inhibitor-1. Significant alterations were found in PT, aPTT, fibrinogen, D-dimers, and protein S, all favoring a state of hypercoagulation for contraceptive containing DRSP/20EE. Both contraceptives containing DRSP/30EE and LNG/30EE promoted changes that favor the hypercoagulability in the coagulant variable PT and in the anticoagulant variables Protein S and Protein C, respectively. We suggest that the progestin drospirenone can contribute to an inadequate balance among procoagulant, anticoagulant, and fibrinolytic factors, since that the contraceptive containing the lowest dose of estrogen and drospirenone (DRSP/20EE) caused a higher number of hemostatic changes.

Genetic variants in Cell Adhesion Molecule 1 (CADM1): a validation study of a novel endothelial cell venous thrombosis risk factor

INTRODUCTION

In a protein C deficient family, we recently identified a candidate gene, CADM1, which interacted with protein C deficiency in increasing the risk of venous thrombosis (VT). This study aimed to determine whether CADM1 variants also interact with protein C pathway abnormalities in increasing VT risk outside this family.

MATERIALS AND METHODS

We genotyped over 300 CADM1 variants in the population-based MEGA case-control study. We compared VT risks between cases with low protein C activity (n=194), low protein S levels (n=23), high factor VIII activity (n=165) or factor V Leiden carriers (n=580), and all 4004 controls. Positive associations were repeated in all 3496 cases and 4004 controls.

RESULTS

We found 22 variants which were associated with VT in one of the protein C pathway risk groups. After mutual adjustment, six variants remained associated with VT. The strongest evidence was found for rs220842 and rs11608105. For rs220842, the odds ratio (OR) for VT was 3.2 (95% CI 1.2-9.0) for cases with high factor VIII activity compared with controls. In addition, this variant was associated with an increased risk of VT in the overall study population (OR: 1.5, 95% CI 1.0-2.2). The other variant, rs11608105, was not associated with VT in the overall study population (OR: 1.0, 95% CI 0.8-1.1), but showed a strong effect on VT risk (OR: 21, 95% CI 5.1-88) when combined with low protein C or S levels.

CONCLUSIONS

In a population-based association study, we confirm a role for CADM1 variants in increasing the risk of VT by interaction with protein C pathway abnormalities.

Genetic markers associated with plasma protein C level in African Americans: the atherosclerosis risk in communities (ARIC) study

Protein C is an endogenous anticoagulant protein with anti-inflammatory properties. Single-nucleotide polymorphisms (SNPs) affect the levels of circulating protein C in European Americans. We performed a genome-wide association (GWA) scan of plasma protein C concentration with approximately 2.5 million SNPs in 2,701 African Americans in the Atherosclerosis Risk in Communities Study. Seventy-nine SNPs from the 20q11 and 2q14 regions reached the genome-wide significance threshold of 5 × 10(-8) . A missense variant rs867186 in the PROCR gene at 20q11 is known to affect protein C levels in individuals of European descent and showed the strongest signal (P = 9.84 × 10(-65) ) in African Americans. The minor allele of this SNP was associated with higher protein C levels (β = 0.49 μg/ml; 10% variance explained). In the 2q14 region, the top SNPs were near or within the PROC gene: rs7580658 (β = 0.15 μg/ml; 2% variance explained, P = 1.7 × 10(-12) ) and rs1799808 (β = 0.15 μg/ml; 2% variance explained, P = 2.03 × 10(-12) ). These two SNPs were in strong linkage disequilibrium (LD) with another SNP rs1158867 that resides in a biochemically functional site and in weak to strong LD with the top PROC variants previously reported in individuals of European descent. In addition, two variants outside the PROC region were significantly and independently associated with protein C levels: rs4321325 in CYP27C1 and rs13419716 in MYO7B. In summary, this first GWA study for plasma protein C levels in African Americans confirms the associations of SNPs in the PROC and PROCR regions with circulating levels of protein C across ethnic populations and identifies new candidates for protein C regulation.

Skin necrosis: a rare complication of protein S deficiency

Hereditary protein S deficiency is an autosomal dominant disorder leading to recurrent venous thrombosis and, less commonly, to arterial thrombosis. Cases of skin necrosis have been documented in patients with protein C or S deficiency while being treated with warfarin. We describe herein a patient with protein S deficiency who developed significant skin necrosis without being exposed to warfarin. She had a protracted clinical course resulting in gangrene and transmetatarsal amputation. Recognition of this rare complication and an earlyhematology referral may prevent dismal outcomes in patients with protein S deficiency.

Reduced protein C Global assay level in infertile women prior to IVF-ET treatment

PURPOSE

In the last few years more robust evidence is emerging to point out at an increased rate of prematurity and low birth weight in singleton pregnancies following ART. Whether this increased rate is related to ART practice or to infertility per se, is still an open question. Our aim in this study was to explore this question by evaluating Protein C (ProC) Global assay in infertile women before ART treatment.

METHODS

A cohort of 95 unselected and consecutive infertile women, eligible for ART, was prospectively recruited for the study. The control group included 77 matched healthy fertile women with a history of spontaneous conceptions. Pro C Global assay was evaluated in both groups. A full thrombophilic work-up was performed in the study group.

RESULTS

ProC Global assay level was found to be significantly lower in the study as compared to the control group, corresponding to 0.78 ± 0.16 and 0.88 ± 0.16, respectively (P < 0.01). As well, abnormal ProC Global assay level of ≤ 0.8 was significantly higher in the study as compared to control group corresponding to 53 % and 29 %, respectively. ProC Global assay level was significantly lower in women within the study group found to have APCR, factor V Leiden and high factor VIII level, any thrombophilia or combined thrombophilia when compared to women without these thrombophilic risk factors.

CONCLUSIONS

Reduced ProC Global assay level is encountered in infertile women prior to ART treatment. This finding may suggest a unique anticoagulation Protein C pathway in infertile as compared to fertile women. Further studies are encouraged to explore this finding.

Protein C

Protein C (PC) is a 62-kDa vitamin K-dependent plasma zymogen which, after activation to serine protease, plays an important role in the physiologic regulation of blood coagulation. Given that PC is one of the major naturally occurring inhibitors of coagulation, acquired or hereditary deficiencies of this protein result in excessive thrombin generation. As a vast array of mutations are responsible for hereditary PC deficiencies, screening for their presence by DNA testing would require sequencing each entire gene involving numerous exons. Moreover, the knowledge of the gene mutation does not offer any benefit in the treatment of thrombophilic families, so the routine molecular characterization is not indicative. These defects are detected by functional or immunological assays. Measurement of PC activity is essential to identify subjects with both type I and type II PC defects. There is no need to routinely perform PC immunological assays. However, they are useful in order to distinguish type I from type II PC hereditary deficiency.

[Thrombophilia - a risk factor of retinal vein occlusion?]

To evaluate thrombophilia as a risk factor of retinal vein occlusion in comparison with a control group and a general polish population.

MATERIAL AND METHODS

Fifty nine consecutive patients with retinal vein occlusion were enrolled in this study. The diagnosis of retinal vein occlusion was based on the presence of typical findings in the eye fundus, fluorescein angiography, and optical coherence Stomography. Control group consisted of 59 subjects matched for age, sex, body mass index (BMI), medications, and cardiovascular risk factors. In all patients the following thrombophilic factors were evaluated: factor V mutation, 20210A prothrombin mutation, MTHFR (methy-lenetetrahydrofolatereductase) mutation C677T, protein C and free protein S level, antithrombin activity, factor VIII activity, anty-beta2 glikoprotein I antibodies level, anticardiolipin antibodies level, the presence of lupus anticoagulant, total homocysteine concentration.

RESULTS

In both groups with retinal vein occlusion and control group a high incidence of factor V Leiden was observed: 10.2% and 15.6%, respectively. In one patient the presence of 20210A prothrombin mutation was noted and in one the deficiency of free S protein was observed. Antiphospholipid antibodies were present in 11.8% of cases and factor VIII concentration > 150% in 3% of patients with retinal vein occlusion. In 8.5% of patients with retinal vein occlusion genotype TT MTHFR was present. Hyper-homocysteinemia was found in 5 cases with retinal vein occlusion (8.5%) and in 7 in a control group (11.9%). In a venous blood of patients with retinal vein occlusion homocysteine level was lower by 14.5% as compared with a control group (9.4 [7.0-11.3] vs. 11.0 [9.4-12 .8] micromol/l, p = 0.001).

CONCLUSIONS

The results of thrombophilia screening in patients with retinal vein occlusion showed no statistical differences as compared with a control group matched for age, sex, and cardiovascular risk factors. However patients with retinal vein occlusion showed statistically significant lower serum homocysteine concentration as compared with a control group. Two times higher prevalence of factor V Leiden was observed in patients with retinal vein occlusion than in Polish general population.

Enhanced thrombin generation and depressed anticoagulant function in children with pneumonia

AIMS

To clarify the status of the coagulation system in children with community-acquired pneumonia.

METHODS

Coagulation activation markers (prothrombin fragment F1 + 2, thrombin-antithrombin complexes, D-dimer), the natural anticoagulants (antithrombin, protein C and S) and tissue factor were measured in 28 consecutive children with pneumonia on admission to the hospital. Patients were divided into those with either bacterial-type pneumonia (at least two of the following three criteria: plasma C-reactive protein (CRP) >80 mg/L, white blood cell count >15 × 10(9) /L and alveolar infiltrates on the chest radiograph) or viral-type pneumonia.

RESULTS

The majority of the patients (79%) showed elevation of at least one of the three coagulation activation markers. Plasma CRP concentration correlated with F1 + 2 (R = 0.44, p < 0.05) and D-dimer (R = 0.71, p < 0.0001). Patients with bacterial-type pneumonia (n = 17) had higher D-dimer levels (p < 0.05) and lower levels of antithrombin (p = 0.005) and protein C (p = 0.08) than the patients with viral-type pneumonia.

CONCLUSIONS

Children with community-acquired bacterial-type pneumonia show distinctive changes in their coagulation system. The finding of coagulation system activation and depressed function of natural anticoagulants in uncomplicated pneumonia helps to understand the rapid and unpredictable changes observed in the coagulation status in patients with more severe forms of disease.

Evaluation of plasma activity level of anticoagulant proteins in patients with acute lymphoblastic leukemia in Shafa hospital Ahwaz 2010

BACKGROUND AND OBJECTIVES

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy as associated with various coagulation abnormalities such as hemorrhage and thrombosis. This study was designed to investigate the distribution pattern of plasma activity level of anticoagulant protein such as proteins C and S, antithrombin, activated protein C resistance (APCR-V) and D-dimer in patients with ALL.

PATIENTS AND METHODS

We studied thirty patients with confirmed ALL admitted in Shafa Hospital Hematology-Oncology and Thalassemia-Hemoglobinopathy Research Center and thirty normal (age and sex matched) subjects as control group. Proteins C and S, antithrombin, APCR-V were measured by coagulation analyzer and D-dimer analysed with Asserachrom D-Di enzyme immunoassay kit in patients and control group.

RESULTS

The mean activity levels of protein C (p = 0.017) and antithrombin (p = 0.014) were significantly lower in patient to group compared to the control group. However, the patient group had significantly elevated mean levels of protein S (p = 0.004) and D-dimer (p = 0.0001) compared to the control grup. About 3% of patients had APCR-V. There was no significant difference in APCR-V found between patient and control group (p = 0.674).

CONCLUSIONS

The hypercoagulability in ALL patients may attribute to the low levels of protein C and antithrombin and the high level of protein S and D-dimer. According to our findings, the use of suitable anticoagulant therapy as a prophylactic measure can be proposed.

Persistent hypocoagulability in patients with septic shock predicts greater hospital mortality: impact of impaired thrombin generation

PURPOSE

Sepsis induces hypercoagulability, hypofibrinolysis, microthrombosis, and endothelial dysfunction leading to multiple organ failure. However, not all studies reported benefit from anticoagulation for patients with severe sepsis, and time courses of coagulation abnormalities in septic shock are poorly documented. Therefore, the aim of this prospective observational cohort study was to describe the coagulation profile of patients with septic shock and to determine whether alterations of the profile are associated with hospital mortality.

METHODS

Thirty-nine patients with septic shock on ICU admission were prospectively included in the study. From admission to day 7, analytical coagulation tests, thrombin generation (TG) assays, and thromboelastometric analyses were performed and tested for association with survival.

RESULTS

Patients with septic shock presented on admission prolongation of prothrombin time, activated partial thromboplastin time (aPTT), increased consumption of most procoagulant factors as well as both delay and deficit in TG, all compatible with a hypocoagulable state compared with reference values (P < 0.001). Time courses revealed a persistent hypocoagulability profile in non-survivors as compared with survivors. From multiple logistic regression, prolonged aPTT (P = 0.007) and persistence of TG deficit (P = 0.024) on day 3 were strong predictors of mortality, independently from disease severity scores, disseminated intravascular coagulation score, and standard coagulation tests on admission.

CONCLUSIONS

Patients with septic shock present with hypocoagulability at the time of ICU admission. Persistence of hypocoagulability assessed by prolonged aPTT and unresolving deficit in TG on day 3 after onset of septic shock is associated with greater hospital mortality.

Thrombotic tendency in diabetes mellitus. Revisiting and revising a study initiated 30 years ago

Studies initiated 30 years ago emphasized that dilute blood clot lysis time was longer in obese diabetic patients than in normal weight diabetics. It was also later reported that when compared to obese women with gluteal and femoral adiposity, the age matched men with abdominal obesity displayed a more delayed clot lysis, higher triglyceride levels and higher cholinesterase activity, as well as more increased concentration of plasminogen activator inhibitor-1 (PAL-1). According to authors' investigations and data in the literature, impaired fibrinolysis in overweight hypertriglyceridemic subjects are mainly due to increased plasma levels of coagulation factor XIII and PAI-1. It could also be demonstrated that plasma clotting factors VII and VIII activities as well as plasma fibrinogen and von Willebrand factor levels were higher in patients with type 2 diabetes and abdominal obesity than in diabetics without obesity. Such findings are supporting data in the literature, insisting on the pathogenic relevance of intraabdominal obesity and of the subsequently enhanced release of fatty acids and of proinflammatory cytokines in the portal flow. Surprisingly anticoagulant plasma proteins C and S levels were found to be increased in overweight and hyperlipidemic patients considered to be at risk for thrombotic complications. Recent data in the literature had however demonstrated that circulating protein C zymogen acquires anticoagulant activity only after its binding to specific receptors on endothelial cell membrane, while proinflammatory cytokines may disrupt this activating interaction with vascular endothelia.

Estimating the cost of redundancy in molecular diagnostics: the case of activated protein C resistance and factor V Leiden

BACKGROUND

The activated protein C resistance--sensitivity ratio in the presence of Factor V deficient plasma (APC-SR/Factor V) exhibits a high sensitivity for factor V Leiden mutation and has been proposed as the diagnostic approach of choice, as an alternative to genetic tests, to evaluate activated protein C resistance. A survey, including 4969 requests, was performed on the activity of a typical Molecular Diagnostics Laboratory in order to estimate the costs due to reagents, instrumentation and personnel.

METHODS

The global costs of three hypothetical diagnostic approaches were compared: (A) exclusive molecular test for FV Leiden; (B) APC-SR alone; (C) APC-SR and the exclusive confirmation of positive results with molecular test.

RESULTS

The global cost for each patient with the three approaches investigated were respectively 42.20 euros (A), 1.09 euros (B), and 433 euros (C). The cost for finding a patient with factor V Leiden mutation was 549.00 euros for A, 14.18 euros for B, and 56.32 euros for C. It was calculated that a decrease of 97.42% and 89.74% can be obtained using the approaches B and C, respectively. The difference in cost between B and C can be justified by the avoidance of false positive cases (6%) and by the impossibility of distinguishing homozygous from heterozygous patients using APC-SR exclusively (B).

CONCLUSIONS

In the case of suspected phenotype APC resistance, we suggest a laboratory approach, which provides the combined and sequential use of ProCGlobal/FV analysis and a subsequent genetic test for positive patients.

Malignant tumours of colon and rectum from the blood clotting view

OBJECTIVES

The relationship between malignant tumours and blood coagulation disorders is generally well known.

BACKGROUND

The authors notice blood coagulation in patients with colorectal cancer and evaluate prothrombotic markers.

METHODS

The authors analyzed a group of 137 patients with malignant tumour of colon and rectum, drew attention to the relationship between level of D-dimer, PAI-1, F 1+2, Protein C and the progress of malignant tumour, its localization, clinical stage, histopathology type, method of surgery considering the stapling use.

RESULTS

Very aggressive and advance tumours have high level of D dimer, plasminogen activator inhibitor I (PAI-1). Prothrombotic fragments 1+2 were significantly higher by anastomotic dehiscence. Protein C level was lower by age from sixty to seventy and in advanced clinical stage.

CONCLUSION

Pre-operative surveys of D dimer, PAI-1, prothrombotic fragments and Protein C give informations abaout risk of thrombosis, far gone of malignant diseases, they clinical stage and histological type. D dimer and PAI-1 have the most clinical value (Fig. 5, Ref. 11).

[Stroke in 19 year-old man with drug and alcohol abuse]

We report a case of a 19 year-old man with stroke, who was taking cocaine, marihuana and alcohol for a few days before hospitalisation. Diagnostic tests showed protein C insufficiency and patent foramen ovale (PFO). As a result of the therapy neurological symptoms have regressed.

Warfarin-induced penile necrosis in a patient with heparin-induced thrombocytopenia

A 56-yr-old man with lung adenocarcinoma presented with subsegmental pulmonary thrombosis. Platelet count on presentation was 531 x 10(9)/L. The patient was anticoagulated with subcutaneous low molecular weight heparin (LMWH). Next day, oral anticoagulation was initiated with 5 mg of warfarin once daily with LMWH and LMWH was discontinued at third hospital day. On the third day of oral anticoagulation therapy, he complained of left leg swelling and prolonged painful penile erection of 24 hr-duration. His platelet count reached a nadir 164 x 10(9)/L at that time, and the patient had a deficiency of protein C and S, with an activity level of 16% and 20% of normal value. Warfarin was stopped and he underwent penile aspiration. The next day, left leg edema and penile erection was disappeared, but penile and glans penis necrosis was started. This case illustrates that processes underlying heparin-induced thrombocytopenia (HIT) may also underlie warfarin-induced skin necrosis.

Laboratory tests for protein C deficiency

Hereditary protein C deficiency is a hypercoagulable state associated with an increased risk for venous thrombosis. The recommended initial test for protein C is an activity (functional) assay, which may be clotting time based or chromogenic. The advantages and disadvantages of the various testing options are presented. The causes of acquired protein C deficiency are much more common than hereditary deficiency. Therefore, this article describes the appropriate steps to take when protein C activity is low, to confirm or exclude a hereditary deficiency. The causes of falsely normal results are also described, including lupus anticoagulants and direct thrombin inhibitors.

Comparison of plasma levels of natural anticoagulants (protein C and protein S) among Jordanian smokers and non-smokers

BACKGROUND

Protein C (PC) with its cofactor free protein S (FPS) are important anticoagulants. Any defect in the PC system is a risk factor for venous thrombosis.

AIMS

To assess the effect of intensity of smoking, and the dose-response for the number of cigarettes smoked on PC and FPS plasma levels.

METHODS

A comparative study was designed and carried out on a convenient sample of 50 healthy non-smokers and 150 non-symptomatic Jordanian male smokers. PC and FPS levels were measured using an automated system (Stago Analyzer, USA).

RESULTS

The plasma level of PC among smokers was 7.2% lower than that among non-smokers (p = 0.02). Moreover, smokers had 15.6% lower circulating FPS than non-smokers (p = 0.001). Furthermore, data showed significant negative correlations between both PC and FPS levels and the intensity of smoking (r = -0.21%, r = -0.23%, respectively; p = 0.01) and the period of smoking (r = -0.15%, r = -0.23%, respectively; p = 0.01, 0.12, respectively).

CONCLUSIONS

The PC and FPS plasma levels were significantly lower in smokers than non-smokers. Both PC and FPS levels correlated inversely with the period and intensity of smoking, and FPS was more sensitive to smoking than PC.

Human protein C concentrate in the treatment of purpura fulminans: a retrospective analysis of safety and outcome in 94 pediatric patients

INTRODUCTION

Purpura fulminans (PF) is a devastating complication of uncontrolled systemic inflammation, associated with high incidence of amputations, skin grafts and death. In this study, we aimed to clarify the clinical profile of pediatric patients with PF who improved with protein C (PC) treatment, explore treatment effects and safety, and to refine the prognostic significance of protein C plasma levels.

METHODS

In Germany, patients receiving protein C concentrate (Ceprotin, Baxter AG, Vienna, Austria) are registered. The database was used to locate all pediatric patients with PF treated with PC from 2002 to 2005 for this national, retrospective, multi-centered study.

RESULTS

Complete datasets were acquired in 94 patients, treated in 46 centers with human, non-activated protein C concentrate for purpura fulminans. PC was given for 2 days (median, range 1-24 days) with a median daily dose of 100 IU/kg. Plasma protein C levels increased from a median of 27% to a median of 71% under treatment. 22.3% of patients died, 77.7% survived to discharge. Skin grafts were required in 9.6%, amputations in 5.3%. PF recovered or improved in 79.8%, remained unchanged in 13.8% and deteriorated in 6.4%. Four adverse events occurred in 3 patients, none classified as severe. Non-survivors had lower protein C plasma levels (P < 0.05) and higher prevalence of coagulopathy at admission (P < 0.01). Time between admission and start of PC substitution was longer in patients who died compared to survivors (P = 0.03).

CONCLUSIONS

This retrospective dataset shows that, compared to historic controls, only few pediatric patients with PF under PC substitution needed dermatoplasty and/or amputations. Apart from epistaxis, no bleeding was observed. Although the data comes from a retrospective study, the evidence we present suggests that PC had a beneficial impact on the need for dermatoplasty and amputations, pointing to the potential value of carrying out a prospective randomised controlled trial.

[Characteristics of serum lipids and vascular platelet hemostasis in medical staff with arterial hypertension]

Vascular complications of arterial hypertension are known to depend not only on the hypertension level, but also on risk factors including also dyslipoproteinemia and disorders of vascular and platelet hemostasis. Therefore studies of early mechanisms underlying arterial hypertension in medical staffers are topical and serve as a basis for early prevention of cardiovascular complications.

[Colorectal malignancies with respect to hemocoagulation]

AIM

Relationship between malignants tumors and damage of hemocoagulation is known. The aim is analyse this damage and evaluate the thrombotic markers. MATERIAL AND METHODICS: Authors analyses group of 137 patients with colorectal malignants tumors. They notifyes to relationship between plasmatic preoperative D dimer, PAI-1, F 1+2, Protein C level with controll group.

RESULTS

Especially aggressive forms of colorectal tumours have increased levels of D dimer and PAI-1. Protrombin fragments 1+2 were enhanced in the course of anastomotic dehiscence. Protein C level was reduced in 6.-7. decade and in advanced clinical stage.

CONCLUSION

Praeoperative thrombotic markers assays inform about risk of thrombosis and clinical diseases stage. They prefere mini-invasive operations procedures. The maximall validity provides D dimer and PAI-1.

Low protein C and incidence of ischemic stroke and coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Protein C is an important plasma natural anticoagulant. Although protein C deficiency increases risk of venous thrombosis, it remains uncertain whether low protein C increases risk of atherothrombosis.

OBJECTIVE

To examine whether low protein C may be a risk factor for ischemic stroke or coronary events in a prospective population-based study.

PATIENTS/METHODS

The Atherosclerosis Risk in Communities Study assessed protein C antigen by ELISA at baseline in 1987-89 and followed participants (n = 13 879) for incident ischemic stroke or coronary events through 2005.

RESULTS

Over a median of 16.9 years of follow-up, 613 ischemic strokes and 1257 coronary heart disease events occurred. Protein C was inversely associated with incidence of ischemic stroke. Adjusted for multiple risk factors, the rate ratios (95% CIs) from highest to lowest quintiles were 1.0, 1.16 (0.90-1.50), 1.22 (0.94-1.58), 1.18 (0.90-1.55) and 1.52 (1.17-1.98). This inverse association was stronger for non-lacunar and cardioembolic stroke than for lacunar stroke. In contrast, there was a positive association between protein C and coronary heart disease in incompletely adjusted models, but no association after adjustment for plasma lipids.

CONCLUSIONS

In this cohort study, low protein C was a risk factor for incident ischemic stroke but not coronary heart disease. Levels of protein C associated with stroke risk were not restricted to the traditional 'deficient' range for protein C (< 0.5 percentile), suggesting that other etiologies for a lower protein C, or genetic variants associated with more subtle changes in protein C, are playing a role in disease pathogenesis.

Thromboelastography as a better indicator of hypercoagulable state after injury than prothrombin time or activated partial thromboplastin time

OBJECTIVES

To investigate the hemostatic status of critically ill, nonbleeding trauma patients. We hypothesized that a hypercoagulable state exists in patients early after severe injury and that the pattern of clotting and fibrinolysis are similar between burned and nonburn trauma patients.

MATERIALS

Patients admitted to the surgical or burn intensive care unit within 24 hours after injury were enrolled. Blood samples were drawn on days 0 through 7. Laboratory tests included prothrombin time (PT), activated partial thromboplastin time (aPTT), levels of activated factor XI, D-dimer, protein C percent activity, antithrombin III percent activity, and thromboelastography (TEG).

RESULTS

Study subjects were enrolled from April 1, 2004, to May 31, 2005, and included nonburn trauma patients (n = 33), burned patients (n = 25), and healthy (control) subjects (n = 20). Despite aggressive thromboprophylaxis, three subjects (2 burned and 1 nonburn trauma patients [6%]) had pulmonary embolism during hospitalization. Compared with controls, all patients had prolonged PT and aPTT (p < 0.05). The rate of clot formation (alpha angle) and maximal clot strength were higher for patients compared with those of controls (p < 0.05), indicating a hypercoagulable state. Injured patients also had lower protein C and antithrombin III percent activities and higher fibrinogen levels (p < 0.05 for all). Activated factor XI was elevated in 38% of patients (control subjects had undetectable levels).

DISCUSSION

Thromboelastography analysis of whole blood showed that patients were in a hypercoagulable state; this was not detected by plasma PT or aPTT. The high incidence of pulmonary embolism indicated that our current prophylaxis regimen could be improved.