Evidence-based approach to thrombophilia testing

Reducing inappropriate inpatient thrombophilia testing through an electronic health record intervention

Current literature does not support routine testing for hereditary and acquired thrombophilia disorders in the inpatient setting. Testing in the acute setting rarely changes patient management or could lead to patient mismanagement. Despite prior educational interventions, continued overuse of inpatient testing warrants further quality improvement measures. A hard-stop best practice advisory pop-up was implemented in the electronic medical record in a multicenter academic hospital system to provide clinicians guidance on the appropriate use of thrombophilia testing at the point of care. Pre- and postintervention retrospective data were collected to assess clinical features before and after implementation. Before the intervention, 271 patients underwent inpatient hypercoagulability testing; after the intervention, 238 patients underwent inpatient hypercoagulability testing. The total number of labs ordered per patient decreased from 1185 to 910, a 13% reduction (P = 0.003). Overall, there was a savings of $23,597 in total direct cost and $123,153 in total charges when comparing the 6-month timeframes before and after the intervention (P < 0.01). Although this study found only mild reductions in thrombophilia testing, it presents a new means of providing point-of-care intervention and education for hypercoagulability testing in the inpatient setting.

Evolving Knowledge on Primary and Secondary Prevention of Venous Thromboembolism in Carriers of Hereditary Thrombophilia: A Narrative Review

The association between heritability of venous thromboembolism (VTE) and thrombophilia was first reported clinically in 1956, later followed by the first description of a congenital cause of hypercoagulability-antithrombin deficiency-in 1965. Since then, our knowledge of hereditary causes of hypercoagulability, which may predispose carriers to VTE has improved greatly. Novel genetic defects responsible for severe thrombophilia have been recently identified and we have learned that a wide range of interactions between thrombophilia and other genetic and acquired risk factors are important determinants of the overall individual risk of developing VTE. Furthermore, therapeutic strategies in thrombophilic patients have benefited significantly from the introduction of direct oral anticoagulants. The present review is an overview of the current knowledge on the mechanisms underlying inherited thrombophilia, with a particular focus on the latest achievements in anticoagulation protocols and prevention strategies for thrombosis in carriers of this prothrombotic condition.

Evolving Knowledge on Primary and Secondary Prevention of Venous Thromboembolism in Carriers of Hereditary Thrombophilia: A Narrative Review

The association between heritability of venous thromboembolism (VTE) and thrombophilia was first reported clinically in 1956, later followed by the first description of a congenital cause of hypercoagulability-antithrombin deficiency-in 1965. Since then, our knowledge of hereditary causes of hypercoagulability, which may predispose carriers to VTE has improved greatly. Novel genetic defects responsible for severe thrombophilia have been recently identified and we have learned that a wide range of interactions between thrombophilia and other genetic and acquired risk factors are important determinants of the overall individual risk of developing VTE. Furthermore, therapeutic strategies in thrombophilic patients have benefited significantly from the introduction of direct oral anticoagulants. The present review is an overview of the current knowledge on the mechanisms underlying inherited thrombophilia, with a particular focus on the latest achievements in anticoagulation protocols and prevention strategies for thrombosis in carriers of this prothrombotic condition.

The utility of hereditary thrombophilia testing among patients with unprovoked venous thromboembolism

INTRODUCTION

Hereditary-thrombophilia (HT) testing is often sent during the evaluation of patients with unprovoked venous thromboembolism (VTE). This remains a frequent practice even though the results of such testing are often of unclear practical significance.

METHODS

We conducted a multicenter retrospective study to assess whether HT is associated with risk of recurrent VTE among patients who discontinue anticoagulation (AC) following an unprovoked VTE.

RESULTS

A total of 528 adult patients were included, 28% of whom (N = 110) tested positive for HT. Median follow-up was 55 months (IQR 40-66 months) following AC discontinuation. One hundred and twenty-four patients (23%) had a recurrent VTE during follow-up, including 29/110 with HT (26%) and 95/418 without HT (23%). Risk of recurrent VTE over time was similar between the two groups (logrank P = .47). The HR for recurrence among patients with HT was 1.17 (95% CI 0.76 to 1.81). On multivariable analysis, HT was not associated with recurrence of VTE (HR with HT = 1.07 (95% CI 0.69-1.65), P = .74). The only factor significantly associated with risk of VTE recurrence on multivariable analysis was presence of PE (as opposed to DVT alone) (HR = 1.54, 95% CI 1.02-2.30, P = .035).

CONCLUSION

The presence of HT was not associated with risk of recurrent VTE in this cohort of patients. These findings underscore the questionable clinical utility of routine thrombophilia testing among patient with unprovoked VTE and suggest that such testing should not be routinely pursued.

Thrombophilia testing in the inpatient setting: impact of an educational intervention

Background

Thrombophilia testing is frequently ordered in the inpatient setting despite its limited impact on clinical decision-making and unreliable results in the setting of acute thrombosis or ongoing anticoagulation. We sought to determine the effect of an educational intervention in reducing inappropriate thrombophilia testing for hospitalized patients.

Methods

During the 2014 academic year, we implemented an educational intervention with a phase implementation design for Internal Medicine interns at Stanford University Hospital. The educational session covering epidemiology, appropriate thrombophilia evaluation and clinical rationale behind these recommendations. Their ordering behavior was compared with a contemporaneous control (non-medicine and private services) and a historical control (interns from prior academic year). From the analyzed data, we determined the proportion of inappropriate thrombophilia testing of each group. Logistic generalized estimating equations were used to estimate odds ratios for inappropriate thrombophilia testing associated with the intervention.

Results

Of 2151 orders included, 934 were deemed inappropriate (43.4%). The two intervention groups placed 147 orders.

A pooled analysis of ordering practices by intervention groups revealed a trend toward reduction of inappropriate ordering (p = 0.053). By the end of the study, the intervention groups had significantly lower rates of inappropriate testing compared to historical or contemporaneous controls.

Conclusion

A brief educational intervention was associated with a trend toward reduction in inappropriate thrombophilia testing. These findings suggest that focused education on thrombophilia testing can positively impact inpatient ordering practices.

Electronic supplementary material

The online version of this article (10.1186/s12911-019-0889-6) contains supplementary material, which is available to authorized users.

Thrombophilia, risk factors and prevention

INTRODUCTION

Fifty-three years after the first description of an inherited prothrombotic condition (antithrombin deficiency), our knowledge on hereditary and acquired causes of hypercoagulability that can predispose carriers to venous thromboembolism (VTE) has greatly improved. Areas covered: Main causes of hereditary thrombophilia are summarized alongside new prothrombotic mutations recently discovered. The main causes of acquired thrombophilia, and namely, antiphospholipid antibody syndrome and hyperhomocysteinemia, are also discussed together with other common acquired prothrombotic states characterized by an increase of procoagulant factors and/or a decrease of natural anticoagulants. Finally, suggestions for thromboprophylaxis in carriers of hereditary thrombophilia according to current guidelines/evidence are made for the most challenging high-risk situations (i.e. surgery, pregnancy, contraception, cancer, economy class syndrome) as well as for the prevention of post-thrombotic syndrome. Expert opinion: A carrier of inherited thrombophilia should be evaluated in the framework of other (genetic and/or acquired) coexisting risk factors for first or recurrent VTE when assessing the need and duration of prevention (primary prophylaxis). Prevention strategies should be tailored to each patient and every situational risk factor. The knowledge of the carriership status of severe thrombophilia in the proband can be important to provide asymptomatic relatives with adequate counseling on thrombophilia screening or primary thromboprophylaxis.

High detection rates of antithrombin deficiency and antiphospholipid syndrome in outpatients aged over 50 years using the standardized protocol for thrombophilia screening

INTRODUCTION

Thrombophilia screening has limited detection efficiency. We assessed the detection rate when a standardized approach to thrombophilia-screened outpatients was used.

METHODS

We analyzed 1185 patients (36.5% males, median age: 43 years [IQR 33-54]) referred to a single center from January 2014 to October 2017 with 11 different clinical indications for thrombophilia screening, which was performed in the adherence to published guidelines. Factor V Leiden, prothrombin G20210A mutation, antithrombin (AT), protein C, protein S deficiencies and antiphospholipid syndrome (APS) were determined.

RESULTS

The overall positivity rate was 37.1% (95% CI 34.3%-39.7%). The highest positivity rate was found in women following VTE during pregnancy/childbirth (64.1%) and provoked VTE patients with positive family history (52.9%). In patients aged >50 years (32.5%), APS was found at a similar rate as in younger subjects (11.4% vs 10.1%), while AT deficiency was detected more frequently in the older group (5.7% vs 2.4%, p = 0.003).

CONCLUSIONS

Standard indications for thrombophilia screening lead to detection rates of 37% or more. Frequent detection of APS and AT deficiency among older patients, which often implies a need for long-term anticoagulation and could impact clinical practice patterns, suggests a benefit of thrombophilia screening in this population in selected clinical circumstances.

Sex hormones and venous thromboembolism - from contraception to hormone replacement therapy

The use of sex hormones such as combined oral contraceptives (COC) or hormone replacement therapy (HRT) increases the risk for venous thromboembolism (VTE) considerably, especially in patients with an increased intrinsic risk for thromboembolic complications. Despite public and media attention and increasing scientific evidence, prescription patterns seem to be hard to change. It is well recognized that the patient's baseline risk is the most relevant factor in the absolute risk for developing VTE. The relative risk increase associated with sex hormones, depends on the type and dosage of hormones, the route of application (oral, vaginal, transdermal), and for COC, on the specific combination of oestrogen and gestagen components. Consequently, a careful decision for or against any specific type of hormone treatment needs to be based on an assessment of the patient's risk profile (disposition) as well as on the treatment-associated risks and benefits (exposition). This review discusses the most common sex hormone treatments in contraception and HRT, the relevance for VTE risk patients, and strategies to counsel patients with regard to hormone use according to their risk profiles. Keywords: Oral contraceptives, hormonal contraception, hormone replacement therapy, venous thromboembolism.

Detection of high-risk thrombophilia with an automated, global test: the Coagulation Inhibitor Potential assay

: The diagnosis of thrombophilia is a cost-consuming and time-consuming process, as each defect should be separately investigated. The Coagulation Inhibitor Potential (CIP) assay is a promising new global test, sensitive for most of the hereditary thrombophilias, developed for manual methodology. We adapt the original method to an optical coagulation analyser. By this automation, the test will be easier, faster and more precise, and it also allows carrying out 18 measurements simultaneously. The CIP assay was performed in 126 healthy subjects and 193 patients with different types of hereditary thrombophilia conditions. Detected with conventional laboratory tests high-risk thrombophilia was present in 70 patients: deficiencies of antithrombin (AT) (n = 12), protein C (PC) (n = 14), protein S (PS) (n = 6), homozygous factor V Leiden (FVL) mutation (n = 9) and combined types (n = 29). Low-risk thrombophilia was present in 123 patients: heterozygous FVL (n = 115) and FII G2010A mutation (n = 8). Significantly lower median CIP values were found for AT-,PC-, PS deficiencies, homozygous and heterozygous FVL mutations and combined thrombophilias (P < 0.01) as compared with healthy controls. There was no significant difference between the heterozygous FIIG20210A (P = 0.669) thrombophilia group and the healthy controls. The best performance of the test was achieved at the cut-off value of 90.0 U (area: 0.981) with 96% sensitivity and 92% specificity in the high-risk thrombophilia group estimated by receiver operating characteristic analysis. The new method seems to be appropriate and reliable for the detection of AT-, PC- and PS deficiencies, homozygous FVL mutation and also for combined deficiencies. The automated CIP test is insensitive to FII G2010A mutation.

Guidance for the evaluation and treatment of hereditary and acquired thrombophilia

Thrombophilias are hereditary and/or acquired conditions that predispose patients to thrombosis. Testing for thrombophilia is commonly performed in patients with venous thrombosis and their relatives; however such testing usually does not provide information that impacts management and may result in harm. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance for thrombophilia testing in five clinical situations: following 1) provoked venous thromboembolism, 2) unprovoked venous thromboembolism; 3) in relatives of patients with thrombosis, 4) in female relatives of patients with thrombosis considering estrogen use; and 5) in female relatives of patients with thrombosis who are considering pregnancy. Additionally, guidance is provided regarding the timing of thrombophilia testing. The role of thrombophilia testing in arterial thrombosis and for evaluation of recurrent pregnancy loss is not addressed. Statements are based on existing guidelines and consensus expert opinion where guidelines are lacking. We recommend that thrombophilia testing not be performed in most situations. When performed, it should be used in a highly selective manner, and only in circumstances where the information obtained will influence a decision important to the patient, and outweigh the potential risks of testing. Testing should not be performed during acute thrombosis or during the initial (3-month) period of anticoagulation.

An Algorithmic Approach to Management of Venous Thromboembolism

Venous thromboembolism (VTE) is associated with significant morbidity and mortality. Factors such as the presence of transient risk factors for VTE, risk of bleeding, and location of deep vein thrombosis (DVT) determine the duration of anticoagulation. Extended anticoagulation is offered to patients with unprovoked pulmonary embolism (PE) or proximal DVT and a low risk of bleeding. Anticoagulation for 3 months is advised in patients with provoked DVT or PE, high risk of bleeding, and isolated distal or upper extremity DVT. In patients with unprovoked PE or proximal DVT and a low risk of bleeding, who want to stop anticoagulation after 3 months, further risk stratification is necessary. Clinical scoring system, and thrombophilia testing otherwise not routinely performed, may be considered to measure risk of annual recurrence in such cases. Short-term anticoagulation may be considered in subsegmental PE and superficial vein thrombosis, particularly if patients are at low risk of bleeding and have persistent risk factors for recurrent VTE. In cases of catheter-associated thrombosis, the catheter need not be removed routinely, and the patient may be anticoagulated for 3 months or longer if the catheter is maintained in patients with cancer. Extensive screening for occult cancer in cases of unprovoked VTE is not beneficial. New oral anticoagulants such as apixaban, rivaroxaban, or dabigatran may be preferred to vitamin K antagonists in patients without cancer or renal failure, more so after the development of reversal agents such as idarucizumab and andexanet alfa.

Clinical adherence to thrombophilia screening guidelines at a major tertiary care hospital

Essentials Thrombophilia screening has significantly increased but has limited clinical utility. We evaluated the positive rate of thrombophilia screening and adherence to published guidelines. Both the positive rate for thrombophilia screening and the adherence to guidelines were low. Guidance implementation is essential to improve current thrombophilia screening practice.

SUMMARY

Background Thrombophilia screening is widely performed but provides limited clinical utility in managing patients predisposed to venous thromboembolism. Although guidelines to limit testing have been published, adherence to those guidelines in the outpatient clinical setting has not been assessed. Objective To evaluate outpatient thrombophilia screening practices at a tertiary academic medical center. Methods We performed a retrospective review of the electronic medical records and a computational analysis of thrombophilia tests collected during a 3-year period (August 2010 to June 2013) at a large teaching hospital. Our primary outcome measures were positive diagnostic yield for thrombophilia and clinician adherence to published thrombophilia screening guidelines in the outpatient setting. Results and Conclusions We found a positive diagnostic yield of 13.8% (95% confidence interval 12.3% to 15.3%) for outpatient thrombophilia screening at our institution. Of the screening tests requiring a second confirmatory assay for definitive diagnosis, only 12% (95% confidence interval 10.3% to 13.7%) were appropriately obtained. We also observed that 73% of patients in our electronic medical record review were inappropriately tested based on existing screening guideline criteria. When parsed by specialty, we identified that hematologists had a higher adherence rate to guideline criteria than do physicians from other specialties. Our study confirms low adherence to thrombophilia screening guidelines across disciplines and indicates the need for continued clinician education.

Plasminogen activator inhibitor-1 4G/5G polymorphism, factor V Leiden, prothrombin mutations and the risk of VTE recurrence

Plasminogen-activator inhibitor (PAI)-1 is an important inhibitor of the plasminogen/plasmin system. PAI-1 levels are influenced by the 4G/5G polymorphism in the PAI-1 promoter. We investigated the relationship between the PAI-1 polymorphism and VTE recurrence, and its possible modification by factor V Leiden (FVL) and prothrombin (PTM) mutations. Patients (n=1,069) from the Malmö Thrombophilia Study were followed from discontinuation of anticoagulant treatment until diagnosis of VTE recurrence or the end of the study (maximum follow-up 9.8 years). One hundred twenty-seven patients (11.9 %) had VTE recurrence. PAI-1 was genotyped by TaqMan PCR. Cox regression analysis adjusted for age, sex and acquired risk factors of VTE showed no evidence of an association between PAI-1 genotype and risk of VTE recurrence in the study population as a whole. However, by including an interaction term in the analysis we showed that FVL but not PTM modified the effect of PAI-1 genotype: patients with the 4G allele plus FVL had a higher risk of VTE recurrence [hazard ratio (HR) =2.3, 95 % confidence interval (CI) =1.5-3.3] compared to patients with the 4G allele but no FVL (reference group) or FVL irrespective of PAI-1 genotype (HR=1.8, 95 % CI=1.3-2.5). Compared to reference group, 5G allele irrespective of FVL was associated with lower risk of VTE recurrence only when compared with 4G allele together with FVL. In conclusion, FVL has a modifying effect on PAI-1 polymorphism in relation to risk of VTE recurrence. The role of PAI-1 polymorphism as a risk factor of recurrent VTE may be FVL dependent.

Thrombophilia diagnosis: a retrospective analysis of a single-center experience

It is estimated that 30-50% of patients suffering from deep vein thrombosis (DVT) could be diagnosed with congenital or acquired thrombophilia. Its diagnosis, however, rarely changes the clinical management, but is associated with significant costs and negative psychological and social aspects. The aim of this study was to perform a retrospective analysis of the causes and clinical consequences of diagnostics for thrombophilia. A retrospective review of the medical records of 5600 patients was performed, 62 of whom had, at the time, been diagnosed for thrombophilia because of a thromboembolic event. A review of the current literature on the validity of diagnostic tests for hypercoagulability in certain clinical conditions was also performed. The most common reason for thrombophilia testing was episodes of lower limb DVT (56%). The most frequently diagnosed abnormalities were the heterozygous form of the V Leiden gene (18%), protein S deficiency (11%), and the anti cardiolipin antibody IgG (11%). In 45% of the patients, laboratory results did not confirm the presence of any congenital thrombophilia. After receiving the results, 11% of the respondents completed oral anticoagulation therapy after 3 months, and 28% of patients qualified for indefinite use of oral anticoagulant therapy. In most of the cases examined, the diagnosis of thrombophilia did not significantly affect the treatment. A common aberration identified in patients with a history of thromboembolic incidents was the coexistence of risk factors for atherosclerosis.

Transforming growth factor (TGF)-β levels and unprovoked recurrent venous thromboembolism

Prediction of recurrence in patients with unprovoked venous thromboembolism (VTE) remains a challenge. Studies of atherosclerosis suggest a protective role of transforming growth factor (TGF)-β. However, the role of TGF-β has not been studied in VTE. The aim of this study was to investigate TGF-β as a predictive marker of recurrent VTE in patients with a first episode of unprovoked VTE. Patients in the Malmö Thrombophilia Study (MATS) were followed after the discontinuation of anticoagulant treatment until the diagnosis of recurrent VTE or the end of the study in December 2008 (mean ± SD 38.5 months ± 27). Among patients with a first episode of unprovoked VTE, we identified 42 patients with recurrent VTE during the follow-up period. Two age- and sex-matched control subjects without recurrent VTE were selected for each patient (n = 84). Plasma levels of the three isoforms of TGF-β (TGF-β1, TGF-β2 and TGF-β3) were quantified simultaneously by TGF-β 3-plex immunoassay. Compared to controls, plasma levels of TGF-β1 and TGF-β2 were significantly lower in patients with recurrent VTE (p < 0.05), whereas no difference was found for TGF-β3. In a multivariate Cox regression analyses, adjusted for inherited thrombophilia, age, sex and BMI, low levels of TGF-β1 [hazard ratio (HR) = 2.2, 95% confidence interval (CI) 1.1-4.3; p = 0.02] and TGF-β2 (HR = 2.4, 95% CI 1.2-4.7; p = 0.01) were independently associated with a higher risk of recurrent VTE. We propose TGF-β1 and TGF-β2 as potential predictive markers for recurrence in patients with unprovoked VTE.

Global hypercoagulability in patients with schizophrenia receiving long-term antipsychotic therapy

BACKGROUND

Patients with schizophrenia are at increased risk of venous thromboembolism. The mechanisms underlying this association are poorly understood.

AIMS

We investigated whether there is a global hypercoagulable state in patients with schizophrenia utilising the overall haemostatic potential (OHP) assay which assesses overall coagulation potential (OCP), haemostatic potential (OHP) and fibrinolytic potential (OFP).

METHOD

Citrated plasma was collected for OHP assays from patients with schizophrenia on long-term antipsychotic treatment and compared with healthy age- and sex-matched controls. Time courses of fibrin formation and degradation were measured by spectrophotometry (absorption of 405nm) after the addition of tissue factor and tissue plasminogen activator to plasma.

RESULTS

Ninety patients with schizophrenia (antipsychotic treatment-15.9±9.7years) and 30 controls were recruited. Patients with schizophrenia had higher rates of smoking and levels of inflammatory markers (high-sensitivity C-reactive protein and neutrophil-to-lymphocyte ratio) than controls. Whilst D-dimer, fibrinogen and platelet count did not differ between patients with schizophrenia and controls, the OCP (54.0±12.6 vs 45.9±9.1, p=0.002) and OHP (12.6±5.8 vs 7.2±3.7, p<0.001) were higher, and OFP was lower (76.6±9.8% vs 84.9±6.4%, p<0.001) in patients with schizophrenia, implying both a hypercoagulable and hypofibrinolytic state in these patients. Importantly, abnormalities in overall coagulation were independently predicted by levels of plasminogen-activator-inhibitor-1, fibrinogen, platelet count, inflammatory markers and plasma triglycerides, suggesting a multifactorial aetiology.

CONCLUSION

Patients with schizophrenia have evidence of a global hypercoagulable and hypofibrinolytic state which may contribute to their increased risk of venous thromboembolism.

High prevalence of protein C, protein S, antithrombin deficiency, and Factor V Leiden mutation as a cause of hereditary thrombophilia in patients of venous thromboembolism and cerebrovascular accident

OBJECTIVES

To determine the frequency of Protein C, Protein S (PC & PS), antithrombin deficiency (AT III) and Factor V Leiden mutation (FVL) as a cause of thrombophilia in the patients with venous thromboembolism (VTE) and cerebrovascular accident (CVA).

METHODS

It was an observational study conducted at Department of Haematology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. All patients referred for thrombophilia screening from July 2009 to June 2012 were screened. Patients with evidence of VTE or CVA were screened for PC & PS, AT III deficiency, and FVL.

RESULTS

Total 404 patients of age between 1-71 years mean 33 ± 14 with male to female ratio of 2.4:1 had evidence of thrombophilia. Two hundred eighteen (54%) patients presented with CVA, 116 (29%) with deep vein thrombosis (DVT), 42 (10.5%) with pulmonary embolism (PE), and 28 (7.5%) with portal or mesenteric vein thrombosis (PV). Protein C & S deficiency was detected in 35/404 (8.7%), ATIII in 9/404 (2%), and FVL in 25/173 patients (14.5%). The findings were suggestive of a significant association of FVL mutation for developing DVT (OR=11.0, 95% C I 4.6-26.3), CVA (OR=5.7, 95% C I 2.1-15.1), and PV (OR=5.4, 95% C I 1.3-21.9). PC & PS deficiency was a significant risk factor for developing PE (OR=3, 95% C I 0.8-11.4).

CONCLUSION

FVL mutation and Protein C & S are the leading causes of thrombophilia with strong association of Factor V Leiden mutation as risk for developing DVT.

Hypercoagulable states: an algorithmic approach to laboratory testing and update on monitoring of direct oral anticoagulants

Hypercoagulability can result from a variety of inherited and, more commonly, acquired conditions. Testing for the underlying cause of thrombosis in a patient is complicated both by the number and variety of clinical conditions that can cause hypercoagulability as well as the many potential assay interferences. Using an algorithmic approach to hypercoagulability testing provides the ability to tailor assay selection to the clinical scenario. It also reduces the number of unnecessary tests performed, saving cost and time, and preventing potential false results. New oral anticoagulants are powerful tools for managing hypercoagulable patients; however, their use introduces new challenges in terms of test interpretation and therapeutic monitoring. The coagulation laboratory plays an essential role in testing for and treating hypercoagulable states. The input of laboratory professionals is necessary to guide appropriate testing and synthesize interpretation of results.

[Importance of thrombophilia screening]

Thrombophilia testing denotes a test battery for inherited or acquired features associated with a tendency for clot formation. Currently, it is being used in a frequency and to an extent which is not supported by evidence. In order to protect patients from unnecessary worry and stigmatization, but also for reasons of cost effectiveness, thrombophilia testing should be reduced to a very small number of medically justifiable indications which are outlined in this review.Those indications include the following: secondary prevention of venous thromboembolism in patients from a thrombophilic family, i.e., with two or more first degree relatives with venous thromboembolism (VTE), or patients with suspected antiphospholipid syndrome; women prior to oral contraception or planning to become pregnant if they had no prior VTE but have one or more first-degree relatives with VTE-provided they are willing to follow the consequences of positive test results; women with recurrent miscarriage. The inappropriate indications are discussed as well.The test panel for inherited thrombophilias includes deficiencies of antithrombin, protein C and protein S, factor V Leiden and prothrombin 20210 mutation. Patients with suspicion of antiphospholipid syndrome have to be tested for lupus anticoagulans, anti-cardiolipin antibodies, and anti-β2-glycoprotein I-antibodies. It is important to do the blood sampling at an appropriate point in time.

Spontaneous central vein thrombosis in a patient with activated protein C resistance and dengue infection: An association or causation?

Spontaneous central vein thrombosis is a rare and potentially fatal condition in critical care setting. Activated protein C resistance due to homozygous factor V Leiden mutation is an exceptional cause of central venous thrombosis. We recently treated a healthy female student who presented with acute febrile illness, septic shock, and encephalopathy. Neck ultrasonography (USG) prior to an attempt of right internal jugular vein (IJV) cannulation revealed non compressibility of the vein along with absence of venous blood flow. Right IJV and subclavian vein thrombus was confirmed subsequently in USG Doppler by radiologist. Radiological evidence of distal pulmonary artery embolism in pulmonary angiography was also evident. Further investigations demonstrated homozygous Factor V Leiden mutation and activated factor C resistance and Dengue IgM positivity in our patient. Intravenous heparin followed by oral vitamin K anticoagulants (OVKA) aided in her recovery. Spontaneous intravascular thrombosis with activated protein C resistance and the relationship of acute Dengue infection were explored in our report.

Venous thromboembolism risk assessment in hospitalised patients: a new proposal

OBJECTIVE

Cross-sectional studies have been conducted to evaluate the adequacy of prophylaxis for venous thromboembolism. However, these studies often evaluate prophylaxis on the data collection day, without analysing the prophylactic dose or duration and without reference to inappropriate use in patients without risk. A prospective, observational study was performed to assess the adequacy of prophylaxis in a general medicine ward of a university hospital.

METHOD

In the analysis, the use of the proper prophylactic dose at the correct time, the use in patients with contraindications, and the misuse in patients without risk of venous thromboembolism were considered.

RESULTS

A total of 245 patients were evaluated. Of these patients, 104 (42.4%) were considered to be at risk, and 82.7% either received adequate prophylaxis (i.e., the correct dose at the right time) or did not receive prophylaxis because it was contraindicated. Among the 141 patients who were not at risk, 81 (57.4%) incorrectly received prophylaxis, the majority (61/81) of whom presented with risk factors but did not demonstrate reduced mobility. Among the entire group, only 59.6% of patients were properly treated.

CONCLUSIONS

The evaluation of prophylaxis adequacy should consider not only whether the correct dose is administered at the correct time but also whether it is used in patients with contraindications and whether it is inappropriately administered to patients who are not at risk.

Thrombosis in women: what are the knowledge gaps in 2013?

Several aspects of the diagnostic and therapeutic management of women with venous thrombosis are uncertain. In this overview, I will discuss three major areas. First, the contribution of hormone use to venous thromboembolism (VTE) will be discussed as prudent prescribing of safe preparations can further reduce the risk of hormone-related VTE. Uncertainties remain regarding certain low-dose progestagens and transdermal routing of hormones and their associated risk of VTE. Second, I will review the diagnosis, treatment, and prevention of pregnancy-related VTE. As direct evidence is largely absent for these individuals, these areas are subject to extrapolation from the non-pregnant population. There is therefore an urgent need for the evaluation of diagnostic strategies that safely exclude the diagnosis of acute pulmonary embolism in pregnant women without the need for diagnostic imaging, which is currently the gold standard, as no studies have confidently demonstrated the safety of ruling out VTE by clinical probability assessment combined with the use of D-dimer levels. Although identification of women at increased risk of pregnancy-related VTE is relatively well established, controversy remains for asymptomatic women from thrombophilic families. The optimal duration and intensity of anticoagulant treatment for, and prophylaxis of, pregnancy-related VTE with low molecular weight heparin is unknown. Third, anticoagulant therapy to prevent recurrence in women with unexplained recurrent miscarriage has shown to have no benefit and should not be prescribed. However, whether antithrombotic therapy prevents recurrent miscarriage in thrombophilic women, or in women with severe pregnancy complications, remains unknown and urgently requires future research.

Thrombophilic abnormalities in patients with or without pulmonary embolism following elective spinal surgery: a pilot study

BACKGROUND

Significance of the thrombophilic abnormalities in development of venous thromboembolism (VTE) has been studies with total hip arthroplasty and acute traumatic spinal cord injury. However, their role as risk factors for VTE in elective spinal surgery remains to be determined.

QUESTIONS/PURPOSES

To determine the role of thrombophilic abnormalities in the development of pulmonary embolism (PE) following elective spine surgery.

METHODS

Case and control groups were created in patients who had undergone elective spinal surgery for degenerative conditions. The PE group comprised 12 patients whose post-operative course was complicated by development of PE. The control group included 12 patients with an uneventful post-operative course. Demographic data including age, gender and surgical procedures were matched between the PE group and the control group. Both groups were evaluated for thrombophilic and hypofibrinolytic risk factors at 3 months post-operatively or later. Blood tests were performed to measure fasting serum homocysteine, antithrombin III, and protein C. Molecular genetic testing was conducted for detection of the plasminogen activator inhibitor-1 4G/4G, and prothrombin 3 UTR gene mutations.

RESULTS

Heterozygous mutation (G20201A) of prothrombin was detected in two patients (16.7%) in the PE group, whereas no such mutation was noted in the control group. Plasminogen activator inhibitor-1 4G/4G homozygous mutation was seen in three in the PE group and two in the control group. Of homocysteine, antithrombin III and protein C, only one patient in each group showed abnormal levels of homocysteine. In total, there half of the patients in the PE group had at least one thrombophilic abnormality, whereas three (25%) patients showed such abnormality in the control group.

CONCLUSION

These findings suggest the involvement of thrombophilic abnormalities, especially the heterozygous G20201A mutation, in the development of PE in patients undergoing elective spinal surgery.

The current role of operative venous thrombectomy in deep vein thrombosis

Patients with acute iliofemoral deep vein thrombosis suffer the most severe post-thrombotic sequelae. The pathophysiology of the post-thrombotic syndrome is ambulatory venous hypertension, and patients with valve dysfunction and luminal obstruction have the highest ambulatory venous pressures. Treatment designed to reduce or eliminate the post-thrombotic syndrome must necessarily remove thrombus to eliminate obstruction. The technique of contemporary venous thrombectomy follows basic vascular surgical principles and offers patients the opportunity for complete or near complete thrombus extraction. The techniques described herein represent the authors' approach to patients with few alternatives to clear their venous system.

Pathology consultation on the laboratory evaluation of thrombophilia: when, how, and why

Venous thromboembolism (VTE) results from the interaction of the Virchow triad (venous stasis, endothelial injury, and hypercoagulability). Risk factors for increased hypercoagulability, or thrombophilia, include activated protein C resistance/factor V Leiden, the prothrombin G20210A mutation, deficiencies of the natural anticoagulants (antithrombin, proteins C and S), antiphospholipid antibodies, hyperhomocysteinemia, and increased factor VIII activity. Not all patients with VTE need to be tested for such risk factors, but patients with thrombophilia should be evaluated for all possibilities to better estimate risk. At the same time, testing should be patient-specific because assay results are affected by preanalytic variables, including thrombosis and anticoagulant therapy.