APTT critical value establishment in four different reagent/instrument systems based on single factor deficiencies.

INTRODUCTION: There are significant differences in the activated partial thromboplastin time (APTT) critical values reported in different studies, most of which does not make recommendations for any specific clear detection systems. The International Council for Standardization in Hematology (ICSH) recommends that APTT critical values be established based on the reagent type, coagulation factor sensitivity and heparin response. The objective of this study was to establish APTT critical values by using different reagents and based on single coagulation factor deficiencies. METHODS: The APTT values were determined in commercial endogenous coagulation factor-deficient plasma at concentrations of 1 IU/dL, 2 IU/dL, 5 IU/dL, 10 IU/dL, 20 IU/dL, and 30 IU/dL by using four assay systems. The retrospective collection of data from patients who lacked factor VIII (FVIII), FIX, or FXI alone was performed. Receiver operating characteristic (ROC) curves were constructed to assess the diagnostic accuracy of APTT for identifying patients with an endogenous coagulation factor activity < 5 IU/dL. RESULTS: The APTT values in the plasma samples with the same concentrations of endogenous coagulation factors were significantly different among the four assay systems (P < 0.001). The suggested critical values of APTT were 40.0 s for Sysmex CS5100 (Actin FSL), 58.0 s for Sysmex CS5100 (Actin), 51.8 s for STA-R Evolution (STA-PTTA), and 64.8 s for ACL TOP 700 (HemosIL SynthasIL). On the basis of the ROC curve, the optimal threshold values for APTT (STA-PTTA) were 55.8 s in patients with a simple deficiency of FVIII (sensitivity = 100%, specificity = 85.7%, area under the ROC curve (AUC) = 0.982), 54.3 s in patients with a simple deficiency of FIX (sensitivity = 100%, specificity = 92.9%, AUC = 0.986), and 71.7 s in patients with a simple deficiency of FXI (sensitivity = 100%, specificity = 94.1%, AUC = 0.992), which were closer (difference of 0.6-2.5 s) to the cutoff points for commercial plasma at equal factor levels. CONCLUSIONS: APTT critical values need to be established for different reagents based on the presence of a single coagulation factor deficiency.

Comparative analysis of thrombin generation platforms for patients with coagulation factor deficiencies: A comprehensive assessment.

INTRODUCTION: Thrombin generation assays (TGAs) assess the overall functionality of the hemostatic system and thereby provide a reflection of the hemostatic capacity of patients with disorders in this system. Currently, four (semi-)automated TGA platforms are available: the Calibrated Automated Thrombogram, Nijmegen Hemostasis Assay, ST Genesia and Ceveron s100. In this study, we compared their performance for detecting patients with congenital single coagulation factor deficiencies. MATERIALS AND METHODS: Pooled patient samples, healthy control samples and normal pooled plasma were tested on all four platforms, using the available reagents that vary in tissue factor and phospholipid concentrations. The TGA parameters selected for analysis were peak height and thrombin potential. Results were normalized by using the calculated mean of healthy controls and a correction for between-run variation. Outcomes were presented as relative values, with the mean of healthy controls standardized to 100 %. RESULTS: Across all platforms and reagents used, thrombin potentials and peak heights of samples with coagulation factor deficiencies were lower than those of healthy controls. Reagents designed for bleeding tendencies yielded the lowest values on all platforms (relative median peak height 19-32 %, relative median thrombin potential 19-45 %). Samples representing more severe coagulation factor deficiencies generally exhibited lower relative peak heights and thrombin potentials. CONCLUSIONS: Thrombin generation assays prove effective in differentiating single coagulation factor deficient samples from healthy controls, with modest discrepancies observed between the platforms. Reagents designed for assessing bleeding tendencies, featuring the lowest tissue factor and phospholipid concentrations, emerged as the most suitable option for detecting coagulation factor deficiencies.

Investigating the Multifaceted Nature of Radiation-Induced Coagulopathies in a Göttingen Minipig Model of Hematopoietic Acute Radiation Syndrome.

Coagulopathies are well documented after acute radiation exposure at hematopoietic doses, and radiation-induced bleeding is notably one of the two main causes of mortality in the hematopoietic acute radiation syndrome. Despite this, understanding of the mechanisms by which radiation alters hemostasis and induces bleeding is still lacking. Here, male Göttingen minipigs received hematopoietic doses of 60Co gamma irradiation (total body) and coagulopathies were characterized by assessing bleeding, blood cytopenia, fibrin deposition, changes in hemostatic properties, coagulant/anticoagulant enzyme levels, and markers of inflammation, endothelial dysfunction, and barrier integrity to understand if a relationship exists between bleeding, hemostatic defects, bone marrow aplasia, inflammation, endothelial dysfunction and loss of barrier integrity. Acute radiation exposure induced coagulopathies in the Göttingen minipig model of hematopoietic acute radiation syndrome; instances of bleeding were not dependent upon thrombocytopenia. Neutropenia, alterations in hemostatic parameters and damage to the glycocalyx occurred in all animals irrespective of occurrence of bleeding. Radiation-induced bleeding was concurrent with simultaneous thrombocytopenia, anemia, neutropenia, inflammation, increased heart rate, decreased nitric oxide bioavailability and endothelial dysfunction; bleeding was not observed with the sole occurrence of a single aforementioned parameter in the absence of the others. Alteration of barrier function or clotting proteins was not observed in all cases of bleeding. Additionally, fibrin deposition was observed in the heart and lungs of decedent animals but no evidence of DIC was noted, suggesting a unique pathophysiology of radiation-induced coagulopathies. These findings suggest radiation-induced coagulopathies are the result of simultaneous damage to several key organs and biological functions, including the immune system, the inflammatory response, the bone marrow and the cardiovasculature.

A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms.

Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.

Elevated thrombin generation in patients with congenital disorder of glycosylation and combined coagulation factor deficiencies.

BACKGROUND: Congenital disorders of glycosylation are rare inherited diseases affecting many different proteins. The lack of glycosylation notably affects the hemostatic system and leads to deficiencies of both procoagulant and anticoagulant factors. OBJECTIVE: To assess the hemostatic balance in patients with multiple coagulation disorders by using a thrombin generation assay. METHOD: We performed conventional coagulation assays and a thrombin generation assay on samples from patients with congenital disorder of glycosylation. The thrombin generation assay was performed before and after activation of the protein C system by the addition of soluble thrombomodulin. RESULTS: A total of 35 patients were included: 71% and 57% had low antithrombin and factor XI levels, respectively. Protein C and protein S levels were abnormally low in 29% and 26% of the patients, respectively, whereas only 11% displayed low factor IX levels. Under baseline conditions, the thrombin generation assay revealed a significantly higher endogenous thrombin potential and thrombin peak in patients, relative to controls. After spiking with thrombomodulin, we observed impaired involvement of the protein C system. Hence, 54% of patients displayed a hypercoagulant phenotype in vitro. All the patients with a history of stroke-like episodes or thrombosis displayed this hypercoagulant phenotype. CONCLUSION: A thrombin generation assay revealed a hypercoagulant in vitro phenotype under baseline condition; this was accentuated by impaired involvement of the protein C system. This procoagulant phenotype may thus reflect the risk of severe vascular complications. Further research will have to determine whether the thrombin generation assay is predictive of vascular events.

On-label compared to off-label four-factor prothrombin complex concentrate use: a retrospective, observational study.

BACKGROUND: Four-factor prothrombin complex concentrate (4F-PCC) is US Food and Drug Administration approved for the urgent reversal of coagulation factor deficiency induced by a vitamin K antagonist complicated by acute major bleeding or in situations in which invasive procedures are urgently needed. Although recent evidence suggests the superiority of 4F-PCC over plasma for on-label indications, the off-label use of 4F-PCC has not been rigorously studied. STUDY DESIGN AND METHODS: Eighty-nine patients receiving 4F-PCC at a single institution from July 2016 to December 2017 were retrospectively analyzed. Two cohorts, "On-Label" and "Off-Label" uses of 4F-PCC, were evaluated, comparing patient characteristics, blood utilization, and clinical outcomes including in-hospital mortality. RESULTS: Patients receiving 4F-PCC for off-label reasons (n = 46) were younger and sicker compared to those receiving 4F-PCC for on-label reasons (n = 43). Notably, the mortality rate for off-label use was approximately twofold greater than the mortality rate for on-label use (26 of 46 [56.5%] vs. 12 of 43 [27.9%]; p = 0.006). Patients receiving 4F-PCC for off-label reasons received more units per patient of each blood component than their on-label counterparts. The average cost estimate per patient for 4F-PCC was similar (approx. $4300) in each cohort. CONCLUSION: 4F-PCC is an effective but expensive treatment option for those requiring urgent reversal of vitamin K antagonist-induced coagulopathy. However, providers should be conscious of the high costs and questionable efficacy when using 4F-PCC off-label.

Variability in international normalized ratio and activated partial thromboplastin time after injury are not explained by coagulation factor deficits.

BACKGROUND: Conventional coagulation assays (CCAs), prothrombin time (PT)/international normalized ratio (INR) and activated partial thromboplastin time (aPTT), detect clotting factor (CF) deficiencies in hematologic disorders. However, there is controversy about how these CCAs should be used to diagnose, treat, and monitor trauma-induced coagulopathy. Study objectives were to determine whether CCA abnormalities are reflective of deficiencies of coagulation factor activity in the setting of severe injury. METHODS: Patients without previous CF deficiency within a prospective database at an ACS-verified Level I trauma center had CF activity levels, PT/INR, aPTT, and fibrinogen levels measured upon emergency department arrival from 2014 to 2017. Linear regression assessed how CF activity explained the aPTT and PT/INR variation. Prolonged CCA values were set as INR greater than 1.3 and aPTT greater than 34 seconds. CF deficiency was defined as less than 30% activity, except for fibrinogen, defined as less than 150 mg/dL. RESULTS: Sixty patients with a mean age of 35.8 (SD, 13.6) years and median New Injury Severity Score of 32 (interquartile range, 12-43) were included; 53.3% sustained blunt injuries, 23.3% required massive transfusion, and mortality was 11.67%. Overall, 44.6% of the PT/INR variance and 49.5% of the aPTT variance remained unexplained by CF activity. Deficiencies of CFs were: common pathway, 25%; extrinsic pathway, 1.7%; and intrinsic pathway, 6.7%. The positive predictive value for CF deficiencies were: (1) PT/INR greater than 1.3:4.4% for extrinsic pathway, 56.5% for the common pathway; (2) aPTT greater than 34 seconds:16.7% for the intrinsic pathway, 73.7% for the common pathway. CONCLUSION: Almost half of the variances of PT/INR and aPTT were unexplained by CF activity. Prolonged PT/INR and aPTT were poor predictors of deficiencies in the intrinsic or extrinsic pathways; however, they were indicators of common pathway deficiencies. LEVEL OF EVIDENCE: Prognostic, level III.

Coagulation Factor Hyperfunction After Subarachnoid Hemorrhage Induces Deep Venous Thrombosis.

OBJECTIVE: To explore the change of coagulation function and associated potential mechanisms and the relationship between coagulation disorders and deep venous thrombosis (DVT) after subarachnoid hemorrhage (SAH) within 3 days of onset. METHODS: A total of 150 patients with SAH within 3 days of onset and 100 healthy individuals were recruited. Thrombelastography analysis and traditional laboratory tests were performed. Tissue factor (TF), tissue factor pathway inhibitor (TFPI) and activated protein C (APC) were tested by using enzyme-linked immunoassay kits. Extremities of patients with SAH were scanned by Doppler ultrasonography. Subgroup analysis was performed in patients with SAH based on the presence or lack of DVT. RESULTS: Compared with control groups, R (an indicator of coagulation factor function in thrombelastography) was significantly decreased (4.32 ± 0.99 minutes vs. 6.00 ± 0.75 minutes; P < 0.001), especially in patients with DVT. TF was significantly increased (20.84 ± 4.15 pg/mL vs. 5.24 ± 1.86 pg/mL; P < 0.001). TFPI was decreased (50.42 ± 5.81 ng/mL vs. 64.10 ± 6.04 ng/mL). APC had no apparent changes. R was negatively correlated with TF (r = 0.358; P < 0.05) and positively correlated with TFPI (r = 0.325; P < 0.05) and APC (r = 0.162; P < 0.05). TF, TFPI, and APC had the same variation characteristics in the DVT subgroup compared with the no DVT subgroup. DVT was associated with R through association analysis (r = 0.369; P < 0.05). The R cutoff value for estimating the presence of DVT was 3.65 minutes. CONCLUSIONS: Coagulation factor hyperfunction may be mainly accompanied within 3 days of SAH onset and may induce DVT. This situation may be associated with TF-TFPI-APC imbalance. R = 3.65 minutes was a potential intervention point to prevent the risk of DVT in this population.

Performance of Activated Partial Thromboplastin Time (APTT): Determining Reagent Sensitivity to Factor Deficiencies, Heparin, and Lupus Anticoagulants.

The activated partial thromboplastin time (APTT) is a useful global assay for the assessment of the contact factor pathway of hemostasis and its inhibitors. The test is usually performed on fully automated analyzers using commercially prepared reagents. The three main clinical areas of interest are detection of factor deficiencies, detection of lupus anticoagulants and in the monitoring of therapy with unfractionated heparin. Methods are described here for assessing APTT reagents for their sensitivity to clotting time prolongation in each of these areas of interest.

Performance and Interpretation of Mixing Tests in Coagulation.

Mixing tests in coagulation studies allow the laboratory to correctly differentiate factor deficiency from inhibitors as the cause of a prolonged clotting time. This is important in terms of subsequent laboratory follow-up and clinical patient management. In this chapter, a suggested method of performing mixing tests is given, with procedures applying two different formulas for interpretation, the percent correction and the index of circulating anticoagulant.

New clotting disorders that cast new light on blood coagulation and may play a role in clinical practice.

Recently several variants of clotting factors have shown a peculiar behavior so that they appear as new defects. The factors involved are FII, FV and FIX. Prothrombin deficiency is usually associated with bleeding. Recently a few prothrombin abnormalities involving Arg396 mutations, have been demonstrated to show antithrombin resistance with the consequent appearance of a thrombophilic state and venous thromboses in young age. The same is true for an abnormal FIX (FIX Padua). The thrombotic manifestations in the latter condition are also venous. The abnormal FIX (FIX Padua) is characterized by a great increase in FIX activity whereas FIX antigen is only slightly increased. The condition is due to an Arg338Lys mutation. The increased intrinsic clotting activity of this abnormal FIX is being investigated as a useful therapeutic approach in homophile B patients. Another new clotting disorder is represented by two abnormal FV (FV East Texas and FV Amsterdam). These are characterized by a deletion of part of the B domain of FV resulting in a "short" FV. The condition is characterized by a mild bleeding tendency due to high levels of Tissue Factor pathway inhibitor. The "short" factor V is in fact resistant to the action of Tissue Factor pathway inhibitor which is sharply increased in these patients. These new clotting entities have again demonstrated that the study of patients who show a tendency to venous thrombosis or a mild bleeding condition that cannot be explained on the basis of our current concepts of blood coagulation, may represent "new" coagulation disorders. All persons interested in thrombotic or hemorrhagic disorders should be informed about these new clinical and laboratory conditions.

Rare bleeding disorders-old diseases in the era of novel options for therapy.

Rare diseases are defined as life-threatening or chronically debilitating diseases with a prevalence of less than one per 2000 according to the European Union or one per 1250 according to the USA. Congenital rare bleeding disorders RBD are reported in most populations, with incidence varying from 1 in 5000 (Hemophilia A), 1:30,000 (Hemophilia B) to much rarer (1:500,000 for FVII deficiency, 1-3 million for Prothrombin or FXIII deficiency). Acquired Hemophilia A is also a rare bleeding disorder with estimated frequency of 1 in million. Most RBDs are inherited as autosomal recessive (AR); however, heterozygous carriers with varying degrees of corresponding factor deficiency may render an unpredictable propensity for bleeding. In patients with bleeding symptoms, laboratory assessment and especially molecular techniques currently enable accurate diagnosis and may provide tools for prenatal and family counseling. Currently hemostasis control is mainly based upon replacement of the missing coagulation factors (unless presence of inhibitors renders it impossible), however future gene therapy and disruptive, non-replacement alternatives may be promising for patients with RBD.

Pulmonary embolism in congenital bleeding disorders: intriguing discrepancies among different clotting factors deficiencies.

Pulmonary embolism is a complication of deep vein thrombosis. It occurs in the population with a normal clotting mechanism, but it may also occur in patients with congenital bleeding conditions. Here, we report on all cases of pulmonary embolism in congenital hemorrhagic disorders. All reported cases of pulmonary embolism in congenital coagulation disorders have been gathered by a time-unlimited PubMed search. Cross-checking of the references listed at the end of the single papers was carried out to avoid omissions. Seventy-two patients had an objectively demonstrated pulmonary embolism. The event occurred in patients with fibrinogen, factor V, factor VIII (FVII), FVIII, FIX, and FXI deficiency, and in those with von Willebrand's disease. No embolism was reported in FII, factor X, and FXIII deficiency. Thirty were women and 28 were men, whereas in the remaining 14 cases, sex was not reported. Age varied from 6 to 81 years (mean age 34.3 years). The management varied from only supportive to the administration of unfractionated heparin, low-molecular-weight heparin, and anti-vitamin K medications, accompanied by adequate replacement therapy. Evolution was fair or good in the majority of cases, but there were 10 fatalities. Risk factors were present in 61 patients. The most frequent of these were replacement therapy (35 cases), surgery (34), and old age (13). Some patients had more than one risk factor. Eleven patients had no risk factors. There are discrepancies in the prevalence of pulmonary embolism among different clotting disorders. The conditions most frequently affected are FVII deficiency and fibrinogen defects. The significance of the findings is discussed.

Do PT and APTT sensitivities to factors' deficiencies calculated by the H47-A2 2008 CLSI guideline reflect the deficiencies found in plasmas from patients?

INTRODUCTION: Prothrombin time (PT) and activated partial thromboplastin time (APTT) sensitivity for detecting isolated factor deficiencies varies with different reagents and coagulometers. The Clinical and Laboratory Standards Institute (CLSI) H47A2 guideline proposed a method to calculate these sensitivities, but some inconsistency has been reported. This study aimed to calculate factor sensitivities using CLSI guideline and to compare them with those obtained from single factor-deficient patients' data. METHODS: Different mixtures of normal pooled and deficient plasmas were prepared (<1IU/dL to 100 IU/dL) according to the CLSI H47A2 guideline. PT with rabbit brain (RB) and human recombinant (HR) thromboplastins, APTT and factors' activities were measured in an ACL TOP coagulometer. Sensitivities (maximum factor concentration that produces PT or APTT values out of the reference range) were calculated from mixtures and from patients with single-factor deficiencies: 17 factor FV, 36 FVII, 19 FX, 39 FVIII, 15 FIX 15 FXI and 24 FXII. RESULTS: PT sensitivity with RB was as follows: FV 38 and 59, FVII 35 and 58, FX 56 and 64 IU/dL; PT sensitivity with HR was as follows: FV 39 and 45, FVII 51 and 50, FX 33 and 61 IU/dL; and APTT sensitivity was as follows: FV 39 and 45, FX 32 and 38, FVIII 47 and 60, FIX 35 and 44, FXI 33 and 43, FXII 37 and 46 IU/dL, respectively. CONCLUSIONS: Reagent-coagulometer combination has adequate sensitivities to factor deficiencies according to guideline recommendations (>30 IU/dL). These should not be considered as actual sensitivities because those obtained by analysing patients' plasmas with single-factor deficiencies were higher for most factors and could induce misinterpretation of the basic coagulation test results.

How do we encounter rare factor deficiencies in children? Single-centre results from Turkey.

BACKGROUND: Rare factor deficiencies (RFDs) are autosomal recessively inherited coagulation factor deficiencies encountered at a frequency of between one in 500, 000 and one in two million. MATERIALS AND METHODS: One hundred and ninety-two patients, diagnosed as having RFD, followed and treated in our clinic between 1990 and 2013 were retrospectively evaluated in this study. RESULTS: From the 192 patients, 142 had FVII, 15 had FX, 14 had FXI, 10 had fibrinogen, six had FV, two had FXIII, two had FV + FVIII and one had FII deficiency. One hundred and thirty of the cases were boys and 62 were girls. The age range was 2 weeks to 24 years and the ages at the admission were between 2 weeks and 16 years. The rate of consanguinity was 49.4%. Eighty-eight of our patients were asymptomatic (45.8%) and 104 were symptomatic (54.2%). Asymptomatic patients were diagnosed by family histories (39.8%), preoperative laboratory studies (54.6%) and operational bleeding (5.6%). Sixty-eight of our symptomatic patients displayed grade II (65.4%) and 36 displayed grade III bleeding symptoms (34.6%). First bleeding regions were skin (33%), nose (28%), central nervous system (CNS) (15.5%), oral cavity (10.5%), soft tissue (6%), joint (3%), urinary system (2%) and gastrointestinal system (GIS) (2%), respectively. The bleeding prevalence rates of our symptomatic patients are listed as epistaxis 62.5%, skin bleedings 53%, oral cavity bleeding 28.8%, haematomas 18.3%, CNS bleedings 17.3%, haemarthrosis 14.4%, GIS bleedings 3.8%, menorrhagia 2.9%, haematuria 1.9%, bleeding because of operations 1.9% and iliopsoas bleedings 1.9%. CNS bleedings (41%) take the first place among the serious bleedings of our cases, followed by haemarthrosis (36.4%), GIS bleedings (18.1%) and iliopsoas bleedings (4.5%). Prophylaxy was applied to nine patients (five patients with FVII, two patients with fibrinogen and one each with FV and FX deficiency). CONCLUSIONS: The characteristics of clinical presentations, first bleeding attacks, bleeding prevalence and severe bleedings as well as prophylactic approaches are discussed in this article.

Clinical analysis of six cases of multiple myeloma first presenting with coagulopathy.

This is a retrospective study on six multiple myeloma patients with upfront coagulopathy and bleeding. A detailed description and analysis of clinical characteristics, coagulation factor deficiencies, treatments and outcome of those six multiple myeloma patients are presented. All six patients presented with significant bleeding. One patient was detected with single factor X deficiency and another with single factor VII (FVII) deficiency, whereas four other patients had complex factor deficiencies. The time from symptom presentation to diagnosis ranged from 3 to 10 months. After correct diagnosis and coagulation factor supplementation, those patients were treated with bortezomib/adriamycin/dexamethasone (PAD) or melphalan/dexamethasone/thalidomide (MTD) regimen. It took 29-71 days (median time 46 days) to completely correct coagulation factor deficiencies since the start of therapy for multiple myeloma. Multiple myeloma patients with acquired bleeding disorders may present with large, deep and multiple sites of haematoma or other types of significant bleeding, which may affect bone marrow examination in some of the cases. Patients may be easily misdiagnosed. The routine examinations of erythrocyte sedimentation rate, serum immunoglobulins and blood urine light chain are the key to diagnosis, hence requiring the treating physician to think broadly and look for traits suggesting myeloma as the underlying cause.

[Thrombin generation assays and their clinical application]. / Trombingenerációs vizsgálatok és klinikai alkalmazásuk.

Thrombin is a key enzyme of the coagulation system, having both pro- and anticoagulant functions. Thus, the generation of thrombin is one of the most important steps in coagulation. Global haemostasis assay, the so-called thrombin generation test is appropriate for its assessment. Since thrombin generation is sensible for both pro- and anticoagulant processes it can be applied for the general characterisation of the risk of thrombosis and bleeding, too. Clinical studies confirmed augmented thrombin generation in patients with high risk of venous or arterial thrombosis. Anticoagulant therapy (also novel oral anticoagulant treatment) can be monitored by thrombin generation. In case of haemophilia thrombin generation assays reflect bleeding severity. It is applicable for monitoring of both conventional haemophilia treatment and inhibitor-bypassing therapy, which is needed when inhibitors develop in patients. Standardization of thrombin generation methods and determination of cut off values are required before its application in clinical practice.

Comparison of thrombin generation assay with conventional coagulation tests in evaluation of bleeding risk in patients with rare bleeding disorders.

Based on the premise that the capacity of plasma to generate thrombin in vitro is a comprehensive and precise functional test of the clotting system, we designed a cross-sectional, single-center study involving 83 patients with rare bleeding disorders (RBDs) to compare the usefulness of the thrombin generation (TG) assay versus conventional tests including prothrombin time (PT) and activated partial thromboplastin time (aPTT) in predicting bleeding risk in patients with RBD in southern Iran. The TG parameters consisted of endogenous thrombin potential, lag time, peak, time to peak (ttPeak), and start tail. The area under the receiver-operating characteristic (ROC) curve showed statistically significant associations between bleeding risk and lag time, ttPeak, and start tail. We determined cutoff values for these 3 TG parameters and obtained a negative predictive value of 86% to 90% in patients with RBD who had a bleeding score (BS) ≤13. The ROC curves for the association of PT and aPTT with BS did not indicate any significant association. Correlation analysis supported the results of ROC curve analysis, only lag time, ttPeak, and start tail showed significant positive correlations with BS (P < .05). Disease severity based on plasma factor activity was significantly associated with prolonged lag time and ttPeak and with prolonged PT (P <.05). We suggest that TG assay is a potentially more useful tool for predicting the bleeding risk in patients with RBD. However, the small sample size in different RBD subgroups precluded subgroup analysis. Prospective multicenter studies with larger numbers of patients are therefore advisable.

Surgical interventions in childhood rare factor deficiencies: a single-center experience from Turkey.

Congenital rare factor deficiencies may present in infancy by life-threatening bleedings or may not show any symptoms until adulthood. It is reported more commonly in countries having consanguineous marriages. Data regarding surgical interventions of rare congenital factor deficiencies are based on case reports and records of guidelines. There are no well documented and separately prepared directories related to pre-surgical and prophylactic approaches of surgical interventions of these deficiencies. Our retrospective study consisted of 171 rare factor deficiencies that were followed up in our clinic, and of whom 61 had 88 surgical interventions between 1990 and 2012. Of these patients, 45 were having factor VII deficiency, and factor V, X, XI, XIII and fibrinogen deficiencies were present in five, four, three, two and two patients, respectively. In 23 patients, factor coagulant activities were under 5% (37.7%), in 15 it was between 5 and 30% (24.6%), and in 23 between 30 and 50% (37.7%). Twenty-eight were symptomatic and 33 were asymptomatic. Information of 51 (83.6%) male and 10 (16.4%) female patients with an age range of 5-25 years (13 ±â€Š5.27), whose age at presentation ranged between 3 weeks and 18 years (7 ±â€Š4.66), were retrieved from patient records and from the records contained in the data-processing environment introduced in 2005. The rate of familial consanguinity was 49.2%. Of the surgical interventions, 24 (27.3%) were major, 24 (27.3%) were minor and 40 (45.4%) were circumcision. We used fresh frozen plasma in 32, recombinant factor (rF)VIIa in 20, prothrombin complex concentrate in five and fibrinogen in three patients during surgical interventions. In 18 patients, antifibrinolytic agents were also used. In 27 patients, surgical interventions were applied without any replacement therapy. No additional doses were required after surgical prophylaxis doses. Thrombotic events were not observed. Antibody occurrence was not detected in these patients. In our study, we evaluated preparation for surgical procedures, factor replacement therapy before surgical intervention and postoperative follow-up in patients with rare coagulation factor deficiency.

Dusart Syndrome in a Scandinavian family characterized by arterial and venous thrombosis at young age.

BACKGROUND: Dysfibrinogenemia is a rare group of qualitative fibrinogen disorders caused by structural abnormalities in the fibrinogen molecule. The laboratory diagnosis of dysfibrinogenemia is controversial. Fibrinogen Paris V, clinically termed Dusart Syndrome, is a dysfibrinogenemia caused by a single base substitution in the gene coding for the Aα-chain of the fibrinogen molecule. OBJECTIVES: To diagnose the first Scandinavian family with Fibrinogen Paris V affecting several family members; the proband, a seven-year-old boy with cerebral vein thrombosis. METHODS: The diagnosis was established following the ISTH guideline for laboratory testing supplemented with fibrin structure analysis and fibrinogen gene analysis. RESULTS: Prolonged thrombin time and reduced ratio between the functional and the protein concentration of fibrinogen were observed in four family members who also were characterized by significantly reduced fibrin polymerization (p < 0.001), reduced fibrin fibre diameter (p < 0.001), reduced fibrin mass-length ratio (p < 0.001) and significantly reduced t-PA-induced fibrinolysis of the fibrin clots (p < 0.001) when compared to controls. Fibrinogen gene analysis demonstrated that five of the family members carried the Fibrinogen Paris V mutation. All laboratory tests were normal in the family members carrying the wild type of the fibrinogen gene. Four of the affected patients had suffered from thrombotic episodes. A noticeable feature in the present family was the presence of both venous and arterial thrombosis. CONCLUSIONS: Excellent concordance was observed between the screening and confirmatory tests, fibrin structure analysis and fibrinogen gene analysis. Fibrin structure analysis should be considered in the laboratory algorithm for diagnosis of dysfibrinogenemia.