Thrombophilia Screening: Universal, Selected, or Neither?

Thrombophilia Screening: Not So Straightforward

Although inherited thrombophilias are lifelong risk factors for a first thrombotic episode, progression to thrombosis is multifactorial and not all individuals with inherited thrombophilia develop thrombosis in their lifetimes. Consequently, indiscriminate screening in patients with idiopathic thrombosis is not recommended, since presence of a thrombophilia does not necessarily predict recurrence or influence management, and testing should be selective. It follows that a decision to undertake laboratory detection of thrombophilia should be aligned with a concerted effort to identify any significant abnormalities, because it will inform patient management. Deficiencies of antithrombin and protein C are rare and usually determined using phenotypic assays assessing biological activities, whereas protein S deficiency (also rare) is commonly detected with antigenic assays for the free form of protein S since available activity assays are considered to lack specificity. In each case, no single phenotypic assay is capable of detecting every deficiency, because the various mutations express different molecular characteristics, rendering thrombophilia screening repertoires employing one assay per potential deficiency, of limited effectiveness. Activated protein C resistance (APCR) is more common than discrete deficiencies of antithrombin, protein C, and protein S and also often detected initially with phenotypic assays; however, some centres perform only genetic analysis for factor V Leiden, as this is responsible for most cases of hereditary APCR, accepting that acquired APCR and rare F5 mutations conferring APCR will go undetected if only factor V Leiden is evaluated. All phenotypic assays have interferences and limitations, which must be factored into decisions about if, and when, to test, and be given consideration in the laboratory during assay performance and interpretation. This review looks in detail at performance and limitations of routine phenotypic thrombophilia assays.

Clinical Investigation of Hereditary and Acquired Thrombophilic Factors in Patients with Venous and Arterial Thromboembolism

Background

The clinical relevance of thrombophilic laboratory factors, especially the "mild" ones, and the need for their screening is not generally recommended in venous (VTE) and/or arterial (ATE) thromboembolism.

Methods

Our aim was to investigate possible associations between comorbidities and 16 inherited/acquired "severe" and "mild" laboratory thrombophilic factors (detailed in introduction) in patients (n=348) with VTE/ATE without a serious trigger (high-risk surgical intervention, active cancer and/or chemo-radiotherapy). Cases with VTE/ATE were enrolled when the thrombotic event occurred under the age of 40, in case of positive family history, recurrent thromboembolism, idiopathic event or unusual location. Patients without a detailed thrombophilia screening or who suffered from both ATE/VTE were excluded to find potential distinct thrombosis type specific thrombophilic risks. The possible role of "mild" factor accumulation was also investigated in VTE (n=266).

Results

Elevation of factor VIII clotting activity was associated with VTE rather than ATE. Varicose veins together with postthrombotic syndrome were strongly related to several "mild" factors. Besides "severe" we found that the "mild" thrombophilic factors were also strongly associated with VTE/ATE. Comorbidities/conditions such as diabetes and smoking were generally associated with hyperlipidemia; moreover, both had a correlation with lipoprotein (a) in VTE. We also revealed an important contribution of "mild" factors in increasing trends of several types and localizations of VTE.

Conclusion

In summary, besides the "severe" thrombophilic factors, the "mild" ones also seem to play a non-negligible role in the manifestation of thrombosis, especially in combination. Therefore, an extended screening might be useful in the personalized recommendation of antithrombotic prophylaxis.

The role of thrombophilias in reproduction: A swot analysis

Thrombophilia is a group of inherited or acquired coagulation disorders that have been associated with reproductive failure. However, there are still no clear recommendations on whether its inclusion in the initial study of the infertile couple or patients with recurrent implantation failure is necessary. In this discussion paper, based on a SWOT (strengths, weaknesses, opportunities, threats) analysis, the different aspects of the repercussions of thrombophilia screening and treatment in reproduction are evaluated. To avoid possible subjectivity in the analysis and results of this study, researchers followed Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed bibliography seem to indicate that, pending new evidence, it would be advisable not to include thrombophilia screening in the initial baseline study of the infertile couple. There is no evidence to support a clear association between thrombophilia and implantation failure or infertility. Thrombophilia testing in this setting may increase cost, with minimal potential benefit and lead to inappropriate use of anticoagulants with possible deleterious adverse effects. Future well-designed studies are needed to assess the possible benefit of anticoagulant therapy in infertile thrombophilic patients with implantation failure.

Protocol for prophylaxis of venous thromboembolism in varicose vein surgery of the lower limbs

Pulmonary embolism is the most feared complication of venous thromboembolism (VTE) and the third leading cause of cardiovascular mortality in the world, after acute myocardial infarction and stroke. The risk of VTE is virtually universal in hospitalized patients, especially those with reduced mobility. Although variable in incidence between clinical and surgical patients, up to 66.6% of events related to hospitalizations can occur after discharge, with this risk remaining for up to 90 days. Despite all the investment made in VTE prophylaxis in recent decades, there is still no consensus or specific guidelines for its prevention in patients undergoing conventional surgery for varicose veins of lower limbs. The adoption of a validated risk assessment model for VTE prophylaxis, based on the current literature, may help in the implementation and standardization of VTE prophylaxis in conventional lower limb varicose vein surgery, in addition to this benefit, it may lead to a reduction in the length of hospital stay and the number of readmissions.

Genomic Analysis of Thrombophilia Variants in the General Population for the Creation of an Effective Preoperative Screening Tool

BACKGROUND

 The loss of a free flap in reconstructive microsurgery is a devastating complication in both the intraoperative and postoperative setting. Previous research has identified a variety of genetic polymorphisms that induce a hypercoagulable state and predispose patients to clot formation and subsequent free flap loss. We aim to review the risks of performing microsurgery on patients who are genetically predisposed to hypercoagulability, as well as identify options, for preoperative screening of inherited thrombophilia.

METHODS

 A thorough literature review was conducted with an online database. A total of 30 studies were reviewed to identify genetic polymorphisms that cause inherited thrombophilia. Through manual review of the literature, a table was created that included thrombotic risk factors and their associated genetic polymorphisms. If the information was available, prevalence for each thrombotic risk was also reported.

RESULTS

 Overall, 18 thrombotic risk factors that contribute to hereditary thrombophilia were identified and linked with specific genes and/or genetic polymorphisms. In studies that did not look at particular ethnic groups, 13 unique thrombotic risk factors were identified. In studies that examined specific ethnic groups exclusively, 12 thrombotic risk factors were identified and related to their respective gene or group of genes. Five of the 18 thrombotic risk factors identified were associated with increased risks of both venous and arterial thrombosis. The remainder of the thrombotic risk factors was associated with increased risk of venous thrombosis exclusively.

CONCLUSION

 The use of genetic screening tests for hereditary thrombophilia in the preoperative setting can serve as an effective preventative measure against postoperative thrombosis. Further exploration of thrombotic risk factors and their related genetic polymorphisms are important steps in reducing postoperative free flap loss.

Successful treatment in one myelodysplastic syndrome patient with primary thrombocytopenia and secondary deep vein thrombosis: A case report

BACKGROUND

The contradictory process of coagulation and anticoagulation maintains normal physiological function, and platelets (PLTs) play a key role in hemostasis and bleeding. When severe thrombocytopenia and deep vein thrombosis (DVT) occur simultaneously, the physician will be confronted with a great challenge, especially when interventional thrombectomy fails.

CASE SUMMARY

We describe a 52-year-old woman who suffered from myelodysplastic syndrome with severe thrombocytopenia and protein S deficiency with right lower extremity DVT. In this patient, the treatment of DVT was associated with numerous contradictions due to severe thrombocytopenia, especially when interventional thrombectomy was not successful. Fortunately, fondaparinux sodium effectively alleviated the thrombus status of the patient and gradually decreased the D-dimer level. In addition, no increase in bleeding was noted. The application of eltrombopag stimulated the maturation and differentiation of megakaryocytes and increased the peripheral blood PLT count. The clinical symptoms of DVT in the right lower extremities in this patient significantly improved. The patient resumed daily life activities, and the treatment effects were independent of PLT transfusion.

CONCLUSION

This is a contradictory and complex case, and fondaparinux sodium and eltrombopag may represent a good choice for the treatment of DVT in patients with severe thrombocytopenia.

Patients with SERPINC1 rs2227589 polymorphism found to have multiple cerebral venous sinus thromboses despite a normal antithrombin level: A case report

BACKGROUND

The hereditary antithrombin (AT) deficiency caused by SERPINC1 gene mutation is an autosomal dominant thrombotic disorder. An increasing number of studies have shown that mutations in the SERPINC1 rs2227589 polymorphic site are correlated with a risk of venous thromboembolism (VTE) at common sites, such as lower extremity deep venous thrombosis and pulmonary thromboembolism. Currently, there are no reports of cerebral venous sinus thrombosis (CVST), a VTE site with a low incidence rate and rs2227589 polymorphism.

CASE SUMMARY

Here, we report a Chinese CVST case with a mutation of the SERPINC1 rs2227589 polymorphic site, which did not cause significant AT deficiency. In a 50-year-old male patient presenting with multiple cerebral venous sinus thromboses no predisposing factors were detected, although a relative had a history of lower extremity deep venous thrombosis. We performed sequencing of the SERPINC1 gene for the patient and his daughter, which revealed the same heterozygous mutation at the rs2227589 polymorphic site: c.41+141G>A.

CONCLUSION

The results showed that more studies should be conducted to assess the correlation between rs2227589 polymorphism and CVST.

Protocolo para a profilaxia do tromboembolismo venoso em cirurgia de varizes dos membros inferiores

RESUMO O tromboembolismo pulmonar é a complicação mais temida do tromboembolismo venoso (TEV) e a terceira causa de mortalidade cardiovascular no mundo, atrás apenas do infarto agudo do miocárdio e do acidente vascular cerebral. O risco de TEV é praticamente universal nos pacientes hospitalizados, especialmente naqueles com redução da mobilidade. Embora variável em incidência entre os pacientes clínicos e cirúrgicos, até 66,6% dos eventos relacionados às internações, podem ocorrer após a alta, permanecendo este risco por até 90 dias. Apesar de todo investimento feito na profilaxia do TEV nas últimas décadas, ainda não existem consensos ou diretrizes específicos para a sua prevenção em pacientes submetidos à cirurgia convencional de varizes dos membros inferiores. A adoção de um modelo de avaliação de risco validado para a profilaxia do TEV, embasado na literatura vigente, poderá ajudar na implementação e padronização da profilaxia do TEV na cirurgia convencional de varizes de membros inferiores, além deste benefício, poderá levar a diminuição do tempo de internação hospitalar e do número de reinternações.

Prevalence of thrombophilia-associated genetic risk factors in blood donors of a regional hospital in southern Brazil

Introduction

Thromboembolic events occur due to an imbalance in the hemostasis and some factors associated with this condition can be inherited. In order to evaluate the frequency of genotypes considered to be common hereditary risk factors for thrombophilia associated with venous thrombosis (g.1691G > A and g.20210G > A) and hyperhomocysteinemia (g.677C > T and g.1298A > C), samples from voluntary healthy blood donors at the Hospital de Clínicas de Porto Alegre were tested.

Methods

We examined 325 blood samples from blood donors collected from October 2017 to July 2018. Blood was collected on filter paper and the DNA was extracted for single nucleotide polymorphisms (SNPs) analysis using the qualitative real time polymerase chain reaction.

Results

The calculated frequencies of each genetic variant in heterozygosity were 4% for the FV gene (g.1691G > A), 4% for the F2 gene (g.20210G > A) and 42% and 39% for methylenetetrahydrofolate reductase (MTHFR), g.677C > T and g.1298A > C, respectively. Only the genetic variants of MTHFR were found in homozygosity, with frequencies of 14% and 6% (g.677C > T and g.1298A > C), respectively.

Discussion

Altogether, these results describe the frequencies of genetic variants associated with venous thrombosis and hyperhomocysteinemia in the analyzed group and are important to enhance our current knowledge about the genetic profiles of Brazilian blood donors.

Thrombophilia screening revisited: an issue of personalized medicine

Clinical thrombophilia is the consequence of multiple gene and/or environment interactions. Thrombophilia screening requires a targeted patient with specific indication, in which a finding would have implications. Carrying out a thrombophilia examination in the physician's practice is often a cause of uncertainty and concern. The concerns begin in choosing the right patient to be examined, are associated with the time of investigation, with the choice of analysis, the test-material and with the correct interpretation of the results. Difficulties, which can influence the results, can occur with both organization and blood sampling. As common for any analysis, pre-analytical, analytical and post-analytical factors should be considered, as well as the possibility of false positive or false negative results. Finally, recommendation of correct therapeutic and prophylactic measures for the patient and his relatives is an additional focus. In this article we want to provide-on the basis of the evidence and personal experience-the theory of thrombophilia-investigation, the indications for testing, as well as practical recommendations for treatment options.

Lung Adenocarcinoma Presenting as Multiple Thromboembolic Events: A Case Report and Review of the Literature

Patients with malignancy may present with significant thromboembolic complications including deep vein thrombosis (DVT), pulmonary embolism, arterial thrombosis, nonbacterial thrombotic endocarditis, and stroke due to abnormal coagulation cascades. Although these events are typically recognized later in the disease process, complications of a hypercoagulable state can rarely present as the first manifestation of an occult malignancy. We report a case of a young male who was ultimately found to have an aggressive form of lung adenocarcinoma after the initial presentation of multiple thromboembolic events. DVT and stroke as an initial presentation of an active lung adenocarcinoma in a young patient is extremely rare as patients presenting in a hypercoagulable state usually are older. Though testing for a hypercoagulable state is not recommended for the first unprovoked DVT, clinicians should be prompted to screen for malignancy in the setting of cryptogenic strokes, especially in younger patients with no prior risk factors.

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.

Requirement for a Pathologist's Second Signature Limits Inappropriate Inpatient Thrombophilia Testing

Thromboembolism is a condition that leads to the hospitalization of thousands of patients in the United States annually. Recent guidelines suggest that testing for hereditary, acquired and combined forms of thrombophilia be delayed following hospitalization for a first-time acute thrombotic event. Instead, thrombophilia testing would be performed in an outpatient setting, at least 1 month after discontinuation of anticoagulant therapy or 3 months after the thrombotic event, on the understanding that anticoagulation may affect some testing. Here, we provide our experience in instituting a system-wide policy change to limit thrombophilia testing in the inpatient setting. The policy change implemented led to a 90% reduction in number of tests ordered. We discuss the cost savings realized by limiting testing. These changes cost nothing to implement. Overall, limiting inpatient thrombophilia testing improves compliance with testing guidelines, provides better care for patients, and allows our institution to better utilize resources.