Clinical guidelines for testing for heritable thrombophilia

The Pathophysiology of Hypercoagulability and Infertility

Alongside an interplay of a multitude of factors, attainment of a favorable pregnancy outcome is predicated on successful implantation, which in itself is a complex process anchored by balanced interchange with the hemostatic system. Among other etiologies, failure of implantation can result in infertility, and lead affected couples to consider assisted reproductive technology (ART) in an effort to fulfill their desire for procreation. Given the critical role of the hemostatic system in the process of implantation, documentation of a hypercoagulable state during controlled ovarian stimulation in the context of in vitro fertilization, as well as the potential association of its derangement in the setting of thrombophilia, with infertility, ART, ovarian hyperstimulation syndrome, and failure of implantation are explored. Additionally, current evidence addressing the relationship between ART and thromboembolism is examined, as is the role of therapy with heparin and aspirin to decrease thrombotic risk and improve ART-related pregnancy outcomes. Evidence-based recommendations from relevant professional societies are summarized.

International Council for Standardization in Haematology (ICSH) laboratory guidance for the verification of haemostasis analyser-reagent test systems. Part 2: Specialist tests and calibrated assays

Before a new method is used for clinical testing, it is essential that it is evaluated for suitability for its intended purpose. This document gives guidance for the performance, verification and implementation processes required by regulatory and accreditation bodies. It covers the planning and verification of specialist haemostatic tests, including factor assays, D-dimers, direct anticoagulants and thrombophilia testing.

Pathogenic variants of PROC gene caused type II activity deficiency in a Chinese family: A case report

RATIONALE

Hereditary Protein C (PC) deficiency is a rare genetic disorder caused by PROC gene mutation. In this article, we report a case of PC deficiency in a Chinese family due to a novel PROC gene mutation.

STUDY SUBJECT

The proband presented with recurrent cerebral infarction over the course of the previous 3 years. He was admitted to the hospital due to signs of mental retardation.

DIAGNOSES

Physical examination, laboratory tests, and magnetic resonance imaging demonstrated that the proband had a manifestation of PC deficiency that included acute cerebral infarction. DNA sequencing analysis revealed a missense variant, c.1015G > A (p.V339 M from valine to methionine) in exon 9 of the PROC gene. In addition, Sanger sequencing confirmed that the proband's son was heterozygous for the same variant. Therefore, the PROC gene mutation was transmitted in an autosomal dominant inheritance manner.

INTERVENTIONS

The patient was treated with a daily dosage of Warfarin (3.5 mg) and was scheduled to undergo regular blood coagulation tests.

OUTCOMES

At the 3-month follow-up appointment, the patient showed improvements in his overall health condition.

LESSONS

We identified a novel missense mutation in the PROC gene in a Chinese family which caused a decrease in the PC antigen level and recurrent cerebral infarction.

Venous Thromboembolism: Genetics and Thrombophilias

Venous thromboembolism (VTE) is a major cause of morbidity and mortality throughout the world. Up to one half of patients who present with VTE will have an underlying thrombophilic defect. This knowledge has led to a widespread practice of testing for such defects in patients who develop VTE. However, identifying a hereditary thrombophilia by itself does not necessarily change outcomes or dictate therapy. Furthermore, family history of VTE by itself can increase an asymptomatic person's VTE risk several-fold, independent of detecting a known inherited thrombophilia. In this article, we will describe the current validated hereditary thrombophilias including their history, prevalence, and association with VTE. With a focus on evaluating both risks and benefits of testing, we will also explore the controversies of why, who, and when to test as well as discuss contemporary societal guidelines. Lastly, we will share how these tests have been integrated into clinical practice and how to best utilize them in the future.

A review of upper extremity deep vein thrombosis

This review aims to describe the epidemiology, pathophysiology, risk factors, presentation, complications, evaluation/diagnosis, and treatment of upper extremity deep vein thrombosis (UEDVT). Upper extremity deep vein thrombosis (UEDVT) accounts for 6% of cases of deep vein thrombosis (DVT). It can lead to swelling and discomfort in that extremity and can be complicated by pulmonary embolism, post-thrombotic syndrome, and recurrence of DVT. Evaluation can begin with a dichotomized Constans score and fibrin degradation product testing. Diagnosis is typically made with compression ultrasound. Anticoagulation is the mainstay of therapy. Primary UEDVT is known as Paget Schroetter Syndrome (PSS) which occurs due to venous thoracic outlet syndrome (vTOS). Anticoagulation, thrombolysis, and decompression of the venous thoracic outlet are used for treatment but the optimal strategy remains to be elucidated. Secondary UEDVT are most commonly caused by indwelling catheters and malignancy. There is an ongoing realization that UEDVT are more than simply 'leg clots in the arm.' Given the increasing incidence, research needs to be done to further our understanding of this disease state, its evaluation, and its treatment.

Real world data on clinical profile, management and outcomes of venous thromboembolism from a tertiary care centre in India

OBJECTIVES

Venous thromboembolism (VTE) is a major cause of mortality and morbidity worldwide. This study describes a real-world scenario of VTE presenting to a tertiary care hospital in India.

METHODS

All patients presenting with acute VTE or associated complications from January 2017 to January 2020 were included in the study.

RESULTS

A total of 330 patient admissions related to VTE were included over 3 years, of which 303 had an acute episode of VTE. The median age was 50 years (IQR 38-64); 30% of patients were younger than 40 years of age. Only 24% of patients had provoked VTE with recent surgery (56%) and malignancy (16%) being the commonest risk factors. VTE manifested as isolated DVT (56%), isolated pulmonary embolism (PE; 19.1%), combined DVT/PE (22.4%), and upper limb DVT (2.3%). Patients with PE (n = 126) were classified as low-risk (15%), intermediate-risk (55%) and high-risk (29%). Reperfusion therapy was performed for 15.7% of patients with intermediate-risk and 75.6% with high-risk PE. In-hospital mortality for the entire cohort was 8.9%; 35% for high-risk PE and 11% for intermediate-risk PE. On multivariate analysis, the presence of active malignancy (OR = 5.8; 95% CI: 1.1-30.8, p = 0.038) and high-risk PE (OR = 4.8; 95% CI: 1.6-14.9, p = 0.006) were found to be independent predictors of mortality.

CONCLUSION

Our data provides real-world perspectives on the demographic sand management of patients presenting with acute VTE in a referral hospital setting. We observed relatively high mortality for intermediate-risk PE, necessitating better subclassification of this group to identify candidates for more aggressive approaches.

Laboratory Limitations of Excluding Hereditary Protein C Deficiency by Chromogenic Assay: Discrepancies of Phenotype and Genotype

Protein C (PC) deficiency is associated with an increased risk for venous thromboembolism (VTE). In daily practice, exclusion of a hereditary PC deficiency is often based on a single determination of PC activity, by either clotting time–based or mostly chromogenic assay. However, diagnosis of hereditary PC deficiency is challenging due to several laboratory and clinical limitations. We compared the potential of PC activity values measured by either chromogenic or clotting time–based assay to predict a variation in the PROC gene. One hundred one (35%) of 287 patients carried variations within the PROC gene, including 2 previously not published variations. In 20 (20%) patients with identified variation, PC activity, determined by chromogenic assay, was within the reference range. For prediction of an underlying genetic defect determined by chromogenic and clotting time–based assay, sensitivity was 80% versus 99%, specificity 75% versus 18%, positive predictive value 64% versus 39%, and negative predictive value (NPV) 88% versus 97%. The lower NPV of chromogenic versus clotting time–based PC assay can be mainly explained by the presence of PC deficiency type IIb. Following our proposed diagnostic algorithm, additional measurement of PC activity by clotting time–based assay in case of a positive VTE history improves detection of this subtype of PC deficiency. Considering potential therapeutic consequences for primary and especially for secondary VTE prophylaxis, genetic analysis is required not only for confirmation but also for clarification of PC deficiency.

Loose Fibrin Clot Structure and Increased Susceptibility to Lysis Characterize Patients with Central Acute Pulmonary Embolism: The Impact of Isolated Embolism

BACKGROUND

 Prothrombotic fibrin clot properties are associated with higher early mortality risk in acute pulmonary embolism (PE) patients. It is unknown whether different types of PE are associated with particular clot characteristics.

METHODS

 We assessed 126 normotensive, noncancer acute PE patients (median age: 59 [48-70] years; 52.4% males), who were categorized into central versus peripheral PE with or without concomitant deep vein thrombosis (DVT). Plasma fibrin clot permeability (K _s), clot lysis time (CLT), thrombin generation, platelet-derived markers, and fibrinolytic parameters were measured on admission. Plasma fibrin clot morphology was assessed by scanning electron microscopy (SEM).

RESULTS

 Patients with central PE (n = 76; 60.3%) compared with peripheral PE (n = 50; 39.7%) had 17.8% higher K _s and 14.3% shortened CLT (both p < 0.01 after adjustment for potential confounders including fibrinogen), with no differences between segmental and subsegmental PE. SEM analysis demonstrated larger fibrin fiber diameter and pore size in central PE compared with peripheral PE (both p < 0.01). For isolated PE, there was 23.3% higher K _s in central PE than in peripheral PE (n = 24; 19%) with no differences in other variables. Central PE combined with DVT (n = 45; 35.7%), as compared with central isolated PE (n = 31; 24.6%), was associated with shortened CLT (all p < 0.05).

CONCLUSION

 Our findings suggest that looser fibrin networks composed of thicker fibers with increased susceptibility to lysis characterize patients with central PE, suggesting that fibrin clot phenotype affects the size of thrombi occluding the pulmonary arteries, highlighting the role of fibrin structures in thrombus formation and stability.

Effect of thrombophilia on clinical outcomes of chronic post-thrombotic patients after iliofemoral stenting with nitinol venous stents

OBJECTIVE

Thrombophilia is a prothrombotic condition that increases the risk of venous thromboembolism. It is unclear whether the presence of thrombophilia alters the clinical outcomes after deep venous stenting. The aim of the present study was to examine the relationship between thrombophilia and outcomes after stenting for post-thrombotic syndrome.

METHODS

Consecutive patients (2012-2017) receiving a nitinol venous stent for chronic post-thrombotic venous occlusive disease with a minimum of 18 months of follow-up in one center using the same anticoagulation protocol were included. The clinical history and thrombophilia testing results were reviewed. The outcomes were stent patency, which was assessed using duplex ultrasonography at 24 hours, 2 and 6 weeks, 3 months, 6 months, and annually thereafter; and reinterventions, which were performed when the stent diameter was <50% or occluded.

RESULTS

Of the 136 patients who had undergone intervention, 55 (40%) had had a provoked deep vein thrombosis (DVT) and 81 (60%) had had an unprovoked DVT and had therefore undergone thrombophilia testing. Of the 81 patients, 38 (47%) had had either inherited (n = 19; 50%) or acquired (n = 19; 50%) thrombophilia. Of the 136 patients who had undergone stenting, 68 had required reintervention (50%) during follow-up to maintain stent patency. Of the 55 patients with a provoked DVT, 29 (53%) had required reintervention. Of the 81 patients with an unprovoked DVT, 39 (48%) had required reintervention (P = .420). Of the 38 patients with unprovoked DVT and thrombophilia, 17 (45%) had required reintervention. Of the 43 patients with unprovoked DVT and no thrombophilia, 22 (51%) had required reintervention (P = .766). The cumulative patency rate was 80% for patients with provoked DVT and 88% for those with unprovoked DVT (P = .193). The presence of thrombophilia was not associated with patency loss (92% cumulative patency for patients with thrombophilia and 84% for patients without thrombophilia; P = .307).

CONCLUSIONS

Using our anticoagulation protocol, patients with and without thrombophilia had similar clinical outcomes after deep venous stenting and should not be excluded from iliofemoral venous stenting. We found no significant differences in outcomes in conjunction with appropriate postoperative anticoagulation therapy.

Anticoagulation in Italian patients with venous thromboembolism and thrombophilic alterations: findings from START2 register study

BACKGROUND

Randomised control trials have assessed the efficacy and safety of direct oral anticoagulants in the prophylaxis and treatment of venous thromboembolism (VTE). Positive but limited results have been reported in patients with inherited thrombophilia. Using an Italian, multicentre, prospective registry of consecutive patients presenting with symptomatic, acute VTE, we aimed to assess which factors are involved in making the choice of the drug that best fits the patient's risk profile in a large real-world setting of VTE patients.

MATERIALS AND METHODS

We investigated 4,866 VTE patients who took oral anticoagulants in the period between 2012 and April 2018 to prevent a new thromboembolic episode.

RESULTS

The large majority of patients who underwent thrombophilic screening, regardless of the results obtained, were prescribed direct oral anticoagulants rather than conventional anticoagulant therapy (p<0.001). During anticoagulation, bleeding events occurred more frequently in patients on conventional anticoagulant therapy (4.2%) than in those receiving direct oral anticoagulants (1.8%) and an increase in bleeding events was observed in patients who tested positive at the thrombophilic screening. Overall, a higher number of recurrent VTE was observed in patients not screened for thrombophilia (n=36; 1.7%) than in those screened (n=20; 0.7%; adjusted odds ratio: 2.2; 95% confidence interval: 1.2-4.1).

DISCUSSION

The present data confirm previous findings from other post-marketing registries and suggest that the choice of oral anticoagulation is strongly driven by patients' characteristics and VTE manifestations. Factors leading to the prescription of thrombophilic screening may identify a patient with a lower risk of VTE recurrence during anticoagulation.

The utility of thrombophilia testing in patients with newly diagnosed portal vein thrombosis

: Thrombophilia testing is frequently performed in both seemingly provoked and unprovoked portal vein thrombosis (PVT), yet the clinical implications of these expensive laboratory tests are unknown. We investigated the frequency of clinical management changes in patients with newly diagnosed PVT. This is a retrospective analysis of adult patients with a newly diagnosed PVT at a single institution. The primary outcome is change in clinical management, defined as documented change in choice, dose, or duration of anticoagulation, future thromboprophylaxis, or counseling of asymptomatic family members. Five-hundred and forty-four patients with PVT were identified, 438 (80.5%) of whom had an identifiable pretesting provoking factor, most commonly cirrhosis (39.2%). Two-hundred ninety-one patients (53.5%) had at least one hypercoagulable laboratory test performed. The most frequently positive test was PAI-1 polymorphism, followed by elevated homocysteine and MTHFR mutational analysis. However, the only test that was frequently positive and consistently altered management was JAK2 mutational analysis (15.3%). Factor V Leiden was commonly positive but rarely changed clinical decision-making (1.5%), as was flow cytometric testing for paroxysmal nocturnal hemoglobinuria (0.8%), and antiphospholipid antibodies (0.7%). Patients with cirrhosis rarely had thrombophilia testing results that were clinically significant. A rough cost estimate was dramatically reduced from $231 000 to $76 000 if only clinically meaningful tests were employed in the hypercoagulable work-up. These results highlight the need for focused thrombophilia testing in patients with PVT.

Current Practice and Clinical Utility of Thrombophilia Testing in Hospitalized Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Testing for thrombophilic disorders is often performed in patients after cryptogenic ischemic stroke in an attempt to identify a hematologic explanation for the event. However, the role of commonly tested thrombophilias in ischemic stroke is poorly defined. There is limited evidence to quantify how these disorders affect ischemic stroke risk and testing practices are highly variable.

METHODS

Retrospective evaluation of thrombophilia testing practices and clinical outcomes was performed in hospitalized patients with acute ischemic stroke (n = 1898) at a large academic hospital over a two-year period. Variables assessed included testing components, timing of testing, number of abnormal results, and frequency of change in clinical management prompted by abnormal results. A provider survey was also performed to assess perceptions of current testing practices and provider understanding of testing indications.

RESULTS

Thrombophilia testing was performed in 190 (10%) patients admitted for acute ischemic stroke. Of those tested, 137 (72.1%) had at least one abnormal result, but this decreased to 37.4% when elevated factor VIII activity was excluded. An abnormal result prompted initiation of anticoagulation in only 4 patients (2%). The provider survey indicated that all providers (100%) were selecting thrombophilia tests using a pre-existing order set and were interested in additional education on testing indications and interpretation. Comparison to similar studies at other institutions revealed significant variation in testing practices, and a small proportion of patients in which testing prompted a change in management (1-8%).

CONCLUSIONS

Thrombophilia testing is frequently obtained in hospitalized patients with acute ischemic stroke, yet testing only changed management in 2% of patients. Efforts to improve provider education and the stewardship of testing are needed to ensure appropriate evaluation and treatment of patients with acute ischemic stroke.

Thrombophilia testing in patients with portal vein thrombosis

Portal vein thrombosis (PVT) is a rare but severe condition. Several risk factors predispose to PVT. However, it remains unclear to which degree thrombophilia contributes to the risk of PVT and whether PVT patients should be routinely referred for thrombophilia testing. The aim of the present study was to investigate the prevalence of thrombophilia in PVT patients to clarify the relevance of thrombophilia testing in PVT patients. Clinical data and results from thrombophilia investigations were systematically obtained from all PVT patients referred to Centre for Hemophilia and Thrombosis, Aarhus University Hospital, Denmark for thrombophilia testing between 1^st of January 2010 and 31^st of December 2018 (n = 93). The investigated thrombophilias included factor V Leiden and prothrombin G20210A mutations, deficiency of protein S, protein C and antithrombin, antiphospholipid syndrome, and increased levels of factor VIII. The prevalence of thrombophilia was compared to healthy controls obtained from previously published data on thrombophilia distribution in cohorts of the Western European adult general population. Comparing PVT patients with healthy controls, significantly increased odds of presence of lupus anticoagulant (crude odds ratio (OR) 6.2, 95% confidence interval (CI) 1.8-20.6) were found, whereas no significantly increased odds of inherited thrombophilia were demonstrated. In conclusion, routine testing for inherited thrombophilia in PVT patients does not seem indicated. However, PVT patients should still be tested for antiphospholipid antibodies because patients meeting the criteria for antiphospholipid syndrome preferentially should receive vitamin K antagonists as anticoagulant therapy.

Ovarian ectopic pregnancy: the role of complex morphopathological assay. Review and case presentation

Ovarian ectopic pregnancy (OEP) represents the rarest type of ectopic pregnancy, accounting for 1-3% of this pathology. The diagnosis of this pathology is challenging due to the non-specific clinical aspects and the ultrasound examination hampered by the lack of visible gestational sac in the presence of hematocele and hemoperitoneum. The purpose of the extended histopathological (HP) examination was to identify particular aspects of the OEP trophoblast and to highlight potential local ovarian modifications which can determine pregnancy fixation at this level. The patient presented local favorable conditions for intraovarian nidation, conditions confirmed by the HP classical examination and by the immunohistochemical evaluation. We identified, using classical Hematoxylin-Eosin, Masson's trichrome and Periodic Acid-Schiff (PAS)-Hematoxylin, necrotic hemorrhage, accentuated vascular thrombosis and high density lymphoplasmocytary infiltrate. These modifications increased local adhesivity and cell destruction through hypoperfusion. Anti-cluster of differentiation antibodies (CD34, CD38, tryptase) revealed the low number of intravillous vessels and the high number of macrophages and mastocytes involved in the local inflammatory process heighten. We identified the presence of trophoblast tissue in the ovarian structure using anti-cytokeratin AE1∕AE3 (CK AE1∕AE3)/anti-cytokeratin 7 (CK7) antibodies. The anti-alpha-smooth muscle actin (α-SMA) and anti-vimentin (VIM) antibodies displayed the density of myofibroblasts and intravillous stromal cells and with the aid of anti-progesterone receptor (PR) antibody, we identified the corpus luteum hormonal response in the OEP. The placental villosities present a blocked multiplication process at the anti-apoptotic B-cell lymphoma 2 (BCL2) protein, confirmed by the Ki67 cell proliferation and tumor protein 63 (p63) immunomarkers. Anti-neuron specific enolase (NSE), anti-calretinin and anti-inhibin A antibodies showed the particular aspects of the granulosa and internal theca cells, which may be involved in oocyte release blockage, intraluteal and extraluteal fecundation of the OEP.

Systems-based hematology: highlighting successes and next steps

Systems-based hematology is dedicated to improving care delivery for patients with blood disorders. First defined by the American Society of Hematology in 2015, the idea of a systems-based hematologist arose from evolving pressures in the health care system and increasing recognition of opportunities to optimize the quality and cost effectiveness of hematologic care. In this review, we begin with a proposed framework to formalize the discussion of the range of initiatives within systems-based hematology. Classification by 2 criteria, project scope and method of intervention, facilitates comparison between initiatives and supports dialogue for future efforts. Next, we present published examples of successful systems-based initiatives in the field of hematology, including efforts to improve stewardship in the diagnosis and management of complex hematologic disorders (eg, heparin-induced thrombocytopenia and thrombophilias), the development of programs to promote appropriate use of hematologic therapies (eg, blood products, inferior vena cava filters, and anticoagulation), changes in care delivery infrastructure to improve access to hematologic expertise (eg, electronic consultation and disorder-specific care pathways), and others. The range of projects illustrates the broad potential for interventions and highlights different metrics used to quantify improvements in care delivery. We conclude with a discussion about future directions for the field of systems-based hematology, including extension to malignant disorders and the need to define, expand, and support career pathways.

Clinical Utilization and Cost of Thrombophilia Testing in Patients with Venous Thromboembolism

Introduction  Testing for inherited and acquired thrombophilias adds to the cost of care of patients with venous thromboembolism (VTE), though results may not influence patient management.

Methods  This is a single-center, retrospective study conducted at Emory University Hospitals from January to December 2015 to (1) determine the pattern of thrombophilia testing in patients with VTE, (2) study the impact of results of thrombophilia testing on clinical decision-making, and (3) determine the direct costs of thrombophilia testing in patients with VTE.

Results  Of the 266 eligible patients, 189 (71%) underwent testing; 51 (26.9%) tested positive and the results impacted management in 32 (16.9%) of tested patients. Patient undergoing testing were more likely to be younger than 40 years (30.9 vs. 18.2%), have had prior pregnancy loss (9.0 vs. 0%), or known family history of hypercoagulability (24.9 vs. 10.4%), and were less likely to have had provoked VTE (37 vs. 79.2%). The most common thrombophilias tested were antiphospholipid syndrome (60.1%), factor V Leiden (59.7%), and prothrombin gene mutation (57.5%). Direct costs of thrombophilia testing were $2,364.32 per patient, $12,331.55 to diagnose 1 positive, and $19,653.41 per patient-management affected.

Conclusion  We noted significant variability in selection of patients and panel of tests, sparse utilization of test results in patient management, but high cost associated with thrombophilia testing in patients with VTE. With guidelines advocating selective use of thrombophilia testing and attention to potential impact of test results in patient management, we propose the need for measures at institutional levels to improve test-ordering practices.

The impact of physician education regarding the importance of providing complete clinical information on the request forms of thrombophilia-screen tests at Tygerberg hospital in South Africa

BACKGROUND

Thrombophilia-screen tests are specialised haemostasis tests that are affected by numerous unique patient variables including the presence of acute thrombosis, the concomitant use of medication and patient demographics. Complete information on the request form is therefore crucial for the haematological pathologist to make patient-specific interpretation of patients' results.

OBJECTIVES

To assess the completeness of thrombophilia-screen test request forms and determine the impact of provision of incomplete information, on the interpretive comments generated by reporting haematological pathologists. To assess the impact of an educational session given to clinicians on the importance of providing all the relevant information on the request forms.

METHOD

Two retrospective audits, each covering 3 months, were performed to evaluate the completeness of demographic and clinical information on thrombophilia-screen request forms and its impact on the quality of the interpretive comments before and after an educational intervention.

RESULTS

One hundred and seventy-one request forms were included in the first audit and 146 in the second audit. The first audit revealed that all 171 thrombophilia-screen request forms had complete patient demographic information but none had clinical information. Haematological pathologists only made generic comments which could not be applied to a specific patient. The second audit, conducted after a physician educational session, did not reveal any improvement in the clinical information provision by the test-ordering physicians. This was reportedly due to the lack of space on the request form. The interpretive comments therefore remained generic and not patient-specific.

CONCLUSION

Physicians' failure to provide relevant clinical information made it impossible for pathologists to make patient-specific interpretation of the results. A single physician education session did not change the practice, reportedly due to the inappropriate design of the test request form. Further studies are required to investigate the impact of an improved request form and the planned electronic test requesting.

Pulmonary embolism: update on management and controversies

Pulmonary embolism is a common and potentially fatal cardiovascular disorder that must be promptly diagnosed and treated. The diagnosis, risk assessment, and management of pulmonary embolism have evolved with a better understanding of efficient use of diagnostic and therapeutic options. The use of either clinical probability adjusted or age adjusted D-dimer interpretation has led to a reduction in diagnostic imaging to exclude pulmonary embolism. Direct oral anticoagulation therapies are safe, effective, and convenient treatments for most patients with acute venous thromboembolism, with a lower risk of bleeding than vitamin K antagonists. These oral therapeutic options have opened up opportunities for safe outpatient management of pulmonary embolism in selected patients. Recent clinical trials exploring the use of systemic thrombolysis in intermediate to high risk pulmonary embolism suggest that this therapy should be reserved for patients with evidence of hemodynamic compromise. The role of low dose systemic or catheter directed thrombolysis in other patient subgroups is uncertain. After a diagnosis of pulmonary embolism, all patients should be assessed for risk of recurrent venous thromboembolism to guide duration of anticoagulation. Patients with a venous thromboembolism associated with a strong, transient, provoking risk factor can safely discontinue anticoagulation after three months of treatment. Patients with an ongoing strong risk factor, such as cancer, or unprovoked events are at increased risk of recurrent events and should be considered for extended treatment. The use of a risk prediction score can help to identify patients with unprovoked venous thromboembolism who can benefit from extended duration therapy. Despite major advances in the management of pulmonary embolism, up to half of patients report chronic functional limitations. Such patients should be screened for chronic thromboembolic pulmonary hypertension, but only a small proportion will have this as the explanation of their symptoms. In the remaining patients, future studies are needed to understand the pathophysiology and explore interventions to improve quality of life.

Managing thromboembolic risk in patients with hereditary and acquired thrombophilias

While we are now able to diagnose inherited thrombophilias in a substantial number of patients with venous thromboembolism (VTE), the initial hope that their presence would inform recurrence risk and thus decisions on anticoagulation duration has largely been disappointing. Indeed, the presence or absence of transient provoking risk factors has proven to be the most important determinant of VTE recurrence risk. Thus, particular attention to transient acquired risk factors for VTE remains paramount, as they have generally been shown to carry more prognostic weight than inherited thrombophilias. The presence of other acquired risk factors may require additional management considerations, whether pertaining to anticoagulant choice, as in antiphospholipid antibody syndrome, or to addressing a new predisposing medical condition, as in malignancy. Antithrombin deficiency or the presence of ≥1 thrombophilic defect may be exceptions that can have a role in prognostication; however, as illustrated in this review through several case vignettes, interpretation and clinical application of the results of inherited thrombophilia testing is nuanced. We have chosen to focus on cases in which patients have been identified as having thrombophilic defects rather than the indications for undertaking testing in the first place or the extent of investigation. Management decisions in such cases ultimately hinge on individualized consideration of the benefits and risks of anticoagulation along with patient preference rather than on an algorithmic pathway based on thrombophilia status.

Des tests génétiques pour prédire des maladies communes

Introduit au lendemain de l’identification des « thrombophilies non rares » (TNR), au milieu des années 1990 afin de prédire et de prévenir la maladie thromboembolique veineuse (MTEV), le bilan génétique pour ces thrombophilies est un exemple assez rare de test génétique de susceptibilité pour une maladie complexe, à avoir franchi le pas d’un véritable usage de routine en clinique. Bien que ce test soit le plus répandu des tests de génétique post-natale en France, son usage (À qui proposer le test ? Que faire des résultats?) fait encore l’objet de débats. Cet article analyse la trajectoire de régulation clinique de ce test et illustre l’importance du contexte spécifique d’usage pour comprendre sa diffusion. Cette analyse vise à nourrir une réflexion plus générale sur les enjeux que pose l’intégration clinique des tests génétiques pour les maladies communes, en considérant notamment les modalités de définition de l’utilité clinique d’un test (statistiqueversusbiologique), des sujets du test (le cas indexversusses apparentés), et des critères en sous-tendant l’accès (modalités des calculs médico-économiques).

Predicting the Risk of Recurrent Venous Thromboembolism: Current Challenges and Future Opportunities

Acute venous thromboembolism (VTE) is a commonly diagnosed condition and requires treatment with anticoagulation to reduce the risk of embolisation as well as recurrent venous thrombotic events. In many cases, cessation of anticoagulation is associated with an unacceptably high risk of recurrent VTE, precipitating the use of indefinite anticoagulation. In contrast, however, continuing anticoagulation is associated with increased major bleeding events. As a consequence, it is essential to accurately predict the subgroup of patients who have the highest probability of experiencing recurrent VTE, so that treatment can be appropriately tailored to each individual. To this end, the development of clinical prediction models has aided in calculating the risk of recurrent thrombotic events; however, there are several limitations with regards to routine use for all patients with acute VTE. More recently, focus has shifted towards the utility of novel biomarkers in the understanding of disease pathogenesis as well as their application in predicting recurrent VTE. Below, we review the current strategies used to predict the development of recurrent VTE, with emphasis on the application of several promising novel biomarkers in this field.

Heritable thrombophilia test utilization and cost savings following guideline-based restrictions: An interrupted time series analysis

OBJECTIVE

Existing guidelines provide indications for appropriate heritable thrombophilia (HT) testing but testing practices often do not conform to these guidelines. The Canadian province of Newfoundland and Labrador (NL) implemented a new 'hard-stop' guideline-based approach to HT testing whereby tests ordered outside specific guidelines were rejected. The objective of this study was to evaluate the effectiveness of this intervention and the associated cost savings.

METHODS

Using data on number of HT tests ordered and performed in NL between December 1, 2014 and February 28, 2018, we conducted interrupted time series analyses to analyze changes in number of HT tests ordered and performed following the intervention. Cost savings were estimated by comparing cost of tests actually performed after enforcement of guidelines with the cost of counterfactual number of tests that would have been performed without guidelines.

RESULTS

Guideline-based restrictions on HT testing were associated with a 86-98% decline in the number of tests performed (p < 0.05). Contrary to previous softer, educational approaches to restricting HT testing, number of Protein C and Factor V Leiden/Prothrombin G20210A tests ordered also declined post-guideline implementation (p < 0.05). Annual cost savings associated with reductions in tests performed were estimated to be $205,154 for NL from a societal perspective. We estimated that if this model was expanded across Canada, annual cost savings could be as large as $14.2 million from a societal perspective.

CONCLUSIONS

A 'hard-stop' guideline-based approach to restricting HT testing is associated with significant reductions in HT testing and meaningful cost savings.

Thrombophilia evaluation in pulmonary embolism

PURPOSE OF REVIEW

Patients with pulmonary embolism commonly undergo thrombophilia evaluation for a variety of reasons including risk stratification for recurrent venous thromboembolism (VTE) and treatment planning. However, the utility of thrombophilia testing in many clinical scenarios remains unclear. This review evaluates current recommendations for thrombophilia testing described in consensus VTE guidelines, recent literature on the clinical application of these recommendations, novel genetic assessments for hereditary thrombophilias, and studies evaluating use of direct oral anticoagulants (DOACs) in VTE patients with thrombophilias.

RECENT FINDINGS

Current VTE guidelines advise limited use of thrombophilia testing, recognizing that testing may be misinterpreted and frequently does not lead to a change in management. Testing and test results are not necessarily benign, are frequently misinterpreted, and can lead to increased anxiety in both patients and clinicians. Recent studies have offered innovative techniques to better align clinical practice with these recommendations as well as expanded genomic assessments to improve the scope and predictive value of thrombophilia testing. There is also emerging literature on the appropriateness of direct oral anticoagulant therapy for VTE patients with hereditary thrombophilias or antiphospholipid syndrome.

SUMMARY

Thrombophilia testing in its current form does not significantly impact clinical management or improve outcomes for most VTE patients. Therefore, it should be employed judiciously and only in patients for whom it is likely to alter clinical management. Novel expanded genomic thrombophilia testing approaches and additional studies evaluating optimal anticoagulant treatment in various thrombophilia subpopulations will make thrombophilia testing more useful for patients moving forward.

Congenital protein C deficiency and thrombosis in a dog

Congenital protein C deficiency is an important cause of thrombosis in humans but is not described in dogs. A 4‐year‐old Hungarian Vizsla was presented for investigation of acute onset of ascites. Computed tomography of the chest and abdomen and echocardiography confirmed a large thrombus within the right ventricle. A cause for thrombosis was not initially identified. The clinical signs resolved rapidly and the dog was administered clopidogrel and discharged. Plasma protein C activity measured 2 and 6 weeks later was markedly lower than expected on both occasions. All known causes of acquired protein C deficiency were excluded, and the dog was diagnosed with a congenital protein C deficiency. After diagnosis, the administration of clopidogrel was stopped and administration of rivaroxaban was started. The dog remains well with no evidence of recurrent thrombosis with 6 months of follow‐up.

Tromboprofilaxis durante el embarazo

Introducción. En mujeres, el riesgo de desarrollar enfermedad tromboembólica venosa (ETV) es 5 a 6 veces mayor durante el embarazo, riesgo que puede aumentar considerablemente si existen antecedentes personales o familiares de otros estados protrombóticos. La ETV es una de las principales causas de morbimortalidad en esta población, por lo que para evaluar la pertinencia de usar tromboprofilaxis, ya sea farmacológica o no farmacológica, es necesario reconocer oportunamente los factores de riesgo clínico asociados a esta condición.Objetivo. Describir el uso de pruebas de tamizaje de estados protrombóticos y de la tromboprofilaxis farmacológica y no farmacológica para prevenir la ETV durante la gestación, durante el parto y durante el puerperio.Materiales y métodos. Se realizó una revisión de la literatura en Embase, ClinicalKey, ScienceDirect, Access Medicine, Scopus, ProQuest, PubMed y LILACS. Se buscaron estudios sobre trombofilia y trombofilaxis en el embarazo publicados entre enero de 2004 y marzo de 2018 en inglés y en español.Resultados. En la búsqueda inicial se identificaron 128 artículos, de los cuales 54 cumplieron los criterios de inclusión. La mayoría de estudios correspondió a revisiones narrativas (n=16), guías de práctica clínica (n=13) y revisiones sistemáticas (n=8).Conclusión. Se recomienda el uso de pruebas de tamizaje de estados protrombóticos durante la gestación, el parto y el puerperio, ya que la identificación oportuna de la ETV permitirá disminuir las tasas de morbimortalidad en esta población mediante la implementación de medidas tromboprofilácticas, sean o no farmacológicas.

Recommendations for clinical laboratory testing for protein C deficiency, for the subcommittee on plasma coagulation inhibitors of the ISTH

Inherited protein C (PC) deficiency increases risk of venous thromboembolism (VTE) by 5 to 10-fold in thrombosis-prone families; however, heterozygous PC deficiency alone does not determine that a subject has thrombophilia. Protein C deficient subjects, who lack additional inherited risk factors such as factor V Leiden or have no major acquired risk factors, may not suffer from VTE. In addition, PC deficiency may be acquired, often due to vitamin K antagonist treatment or liver disease. In contrast, homozygous or compound heterozygous PC deficiencies are rare and serious disorders, and affected infants are often in families with no history of PC deficiency or thrombosis. Laboratories commonly use the chromogenic PC assay to diagnose deficiency. Chromogenic assay is recommended due to its good specificity, but this assay fails to detect the rare type 2b deficiency where the defect is due to poor interaction with calcium ions, phospholipid, protein S, and factor Va and factor VIIIa. The clotting-based assay of PC is capable of detecting type 2b deficiency but it has reduced specificity. Importantly, PC level varies with age, adult reference ranges cannot be applied to babies or children and levels may not reach those of adults even in adolescence. Pre-analytical variables in the specimen affect measurement of PC, and can be assay-dependent; for example, a partially clotted sample will have falsely raised PC level by chromogenic assay but reduced level by clotting-based assay. Direct oral anticoagulants falsely raise PC level in the clotting-based assay but the standard chromogenic assay is unaffected.

Treatment of venous thromboembolism in pediatric patients

Venous thromboembolism (VTE) is rare in healthy children, but is an increasing problem in children with underlying medical conditions. Pediatric VTE encompasses a highly heterogenous population, with variation in age, thrombosis location, and underlying medical comorbidities. Evidence from pediatric clinical trials to guide treatment of VTE is lacking so treatment is often extrapolated from adult trials and expert consensus opinion. Aspects unique to children include developmental hemostasis and the major role of central venous access devices. There is an absence of information regarding the optimal target levels of anticoagulation for neonates and infants and lack of suitable drug formulations. Anticoagulants, primarily low-molecular-weight heparin and warfarin, are used to treat children with symptomatic VTE. These drugs have significant limitations, including the need for subcutaneous injections and frequent monitoring. Randomized clinical trials of direct oral anticoagulants in pediatric VTE are ongoing, with results anticipated soon. These trials will provide new evidence and options for therapy that have the potential to improve care. International collaborative registries offer the ability to study outcomes of rare subgroups of pediatric VTE (eg, renal vein thrombosis), and will be important to ultimately guide therapy in a more disease-specific manner.

CONTRIBUTION OF THE G1691A ALLELE CARRYING OF THE COAGULATION FACTOR V GENE TO THE DEVELOPMENT OF THROMBOSES IN RADIATION-EXPOSED PATIENTS WITH REACTIVE CHANGES IN PERIPHERAL BLOOD

Thrombosis triggers, in addition to «classic» risk factors (RFs) of cardiovascular events, includes the reactive changesof peripheral blood (RCPB), markers of the hereditary thrombophilia and radiation anamnesis. However, results ofmost studies suggest the «classic» RFs are able to neutralize the prothrombogenic potential of the hereditary thrombophilia and other, less powerful predictors of thrombosis.

OBJECTIVE

to determine the influence of the G1691A allele of the proaccelerin gene carrying to the thrombosis development, taking into account the vascular type of their occurrence, the presence of RFs in individuals with RCPB (reactive leukocytosis and thrombocytosis, and secondary erythrocytosis), as well as with and without radiation anamnesis.

MATERIAL AND METHODS

In general, it was analyzed the results of clinical and molecular-genetic data of 152 patientswith RCPB, 19 patients had radiation anamnesis, 133 - did not have. The thrombotic complications were detected in5 (26.31 %) of radiation-exposer patients and 25 (18.79 %) patients without radiation anamneses. The carrying ofthe G1691A allele proaccelerin gene (APG) (Leiden mutation (LM)) was detected using the allele-specific polymerasechain reaction.

RESULTS

The LM was found in 5.9 % (9 carriers) of the general cohort (GC) of RPBC patients. There were no differencein the LM frequency between the groups of patients with and without radiation anamnesis (р = 0.312). In the groupof radiation-exposer patients (р = 0.017), as well as in the group without its (р = 0.031), venous thromboses only weremore frequently in the LM carriers. In the presence of a radiation anamnesis, G1691A APG carriers with RFs have thehigher frequency (р = 0.008) and the probability of the occurrence (relative risk [RR] = 25.00; CI 95 %: 1.56-399.68)of venous thrombosis. In the group without radiation anamnesis, the frequency of venues thrombosis in the LMcarriers is higher in the younger age subgroup (р = 0.001), without RFs (p = 0.044) and without RFs under 60 years(р = 0.023). The risk of venous thrombosis in the G1691A APG carriers of the group without radiation anamnesis is5.78 (95 % CI: 1.58-21.13). In LM carriers without radiation anamnesis and RFs, as well as under the 60 years of age,the probability of venous thrombosis was 6.85 (95 % CI: 1.86-25.22) and 19.40 (95 % CI: 4.64-81.09), respectively,and in the absence of both criteria - 9.57 (95 % CI: 2.49-36.73).

CONCLUSIONS

In patients with and without radiation anamnesis, the risk of venues thrombosis are observed moreoften in carriers of LM. The carrying of the G1691A APG in patients with RPBC and without RA increased the risk ofvenues thrombosis development in subjects without FRs and below 60 years of age. In the radiation-exposure group,the frequency and the risk of venues thrombosis in the G1691A APG carriers was higher in the subgroup with RFs. It isprobably due to the peculiarity of the samples, or prothrombogenic interaction between LM and radiation-associated endothelial damage.

Low molecular weight heparins use in pregnancy: a practice survey from Greece and a review of the literature

Background

Use of LMWH in pregnancy is not only limited to VTE management, but it extends, to the management of vascular gestational complications and the optimization of IVF pregnancies despite the lack of concrete scientific evidence. In this context, we conducted the present study aiming to gain insights regarding the use of LMWH during pregnancy and puerperium. We recorded indication for use, diagnostic work-up as well as the safety and efficacy of the treatment, trying to elucidate the clinical practice in our country.

Methods

We analyzed data regarding 818 pregnant women received LMWH during 2010-2015.Our cohort had a median age of 33.9 years and a BMI of 23.6.There were 4 groups: those with a history of VTE [Group-A: 76], those with pregnancy complications [Group-B: 445], those undergoing IVF [Group-C: 132] and those carrying prothrombotic tendency (thrombophilia, family history of VTE, other) [Group-D: 165]. Mean duration of LMWH administration was 8.6 ± 1.5 months. Out of the total number, 440 received LMWH in fixed prophylactic dose, 272 in higher prophylactic-weight adjusted dose and 106 in therapeutic dose. Moreover, 152 women received in addition low-dose acetylsalicylic acid (ASA). 93.8% of pregnancies were single and 6.2% were multiple ones. Live births occurred in 98.7% of pregnancies.

Results

Anticoagulation was efficacious and well tolerated. Seventeen VTE events were recorded; 7 of them antepartum and 10 postpartum. No major bleeding events were observed while 13 clinical relevant non-major bleeding events were recorded. Regarding gestational vascular complications, 28 IUGR events were recorded, as well as 48 cases of preterm labor of which 12 were concomitant with IUGR (25%). Six early pregnancy losses were recorded; there were 3 fetal deaths and 3 cases of pre-eclampsia/eclampsia.

Conclusions

LMWHs are used extensively during pregnancy and puerperium in Greece for VTE treatment and prophylaxis and for a variety of other indications as well. Although the drug has been shown to be both safe and efficacious, its use for some indications has no proven scientific evidence. In order to clearly define the role of LMWHs in pregnancy, beyond thromboprophylaxis, large prospective studies are required, which could be based on the conclusions of this study.

Guidelines for superficial venous thrombosis

Superficial venous thrombosis (SVT) or superficial thrombophlebitis is characterized by thrombi within superficial veins, with partial involvement or occlusion of the lumen and inflammatory reaction along the course of the vein. Clinical diagnosis tends to be straightforward, but supplementary tests and examinations are needed to confirm thrombosis extension and possible thromboembolic complications. SVT can be associated with deep venous thrombosis in 6 to 40% of cases, with asymptomatic pulmonary embolism (PE) in 20 to 33%, and with symptomatic PE in 2 to 13%. Despite the morbidity and complications, there are currently no Brazilian guidelines for SVT. These guidelines cover the most important issues related to SVT definition, terminology, and etiology, and set out recommendations for diagnosis and treatment.

Discretionary Thrombophilia Test Acquisition and Outcomes in Patients With Venous Thromboembolism in a Real-World Clinical Setting

Background The value of thrombophilia test acquisition in improving risk prediction beyond clinical presentation remains unknown. We investigated the effect of thrombophilia test acquisition on venous thromboembolism (VTE) outcomes. Methods and Results We performed a retrospective cohort study of adult patients over a 15-year period (September 2001 and May 2016) with first diagnosis of VTE in a single academic medical center. Participants were identified by International Classification of Diseases, Ninth Revision (ICD-9), Current Procedural Terminology (CPT) codes and medication history. Participants with thrombophilia testing were matched to control participants without thrombophilia testing using a propensity model. Primary outcomes included recurrent VTE, anticoagulant use 12 months after the index VTE event, bleeding-related hospitalization, and death. From 3590 unique patients who met the inclusion criteria, 747 participants with VTE who underwent thrombophilia testing were matched to a control participant without testing. Tested participants were more likely to have a recurrent event (46.1% versus 28.5%; P<0.001) and an anticoagulant prescription 12 months from the index event (53.9% versus 37.1%; P<0.001) but had no significant difference in bleeding-related hospitalization (11.4% versus 11.8%; P=0.81) compared with untested participants. An abnormal thrombophilia test result, per se, did not predict recurrent VTE (47.8% versus 44.1%; P=0.13), longer duration anticoagulation (53.2% versus 54.8%; P=0.51), bleeding (11.5% versus 11.3%; P=0.70), or mortality (12.2% versus 16.1%; P=0.18) compared with participants who had normal test results. Conclusions The decision to perform thrombophilia testing, but not the test result, is associated with a high risk of recurrent VTE despite a greater likelihood of long-duration anticoagulation.

Hypercoagulable workup in a community hospital setting: to test or not to test; that is the question

Background: Thrombophilia tests are often ordered unnecessarily and/or inappropriately, with significant impact on healthcare costs, hospital resources, time, and potential harm to the patient.

Objective: To identify the incidence of unnecessary and inappropriate thrombophilia testing in a community hospital setting.

Methods: We retrospectively reviewed electronic medical records for patients who underwent inpatient thrombophilia testing at The Brooklyn Hospital Center from 1/1/2018 to 12/31/2018. The indications, and details of the tests, and associated costs were recorded.

Results: A total of 62 patients were included (mean age 45.8, 67.7% female). In 57/62 (91.9%) patients, tests were ordered in the acute phase of thrombosis. At the time the tests were ordered, 29/62 (46.8%) patients were on anticoagulation. Positive results were found in 21/62 (53.2%) patients, but was repeated in only 1/21 (4.7%) patient. Results for 51/62 (82%) patients were obtained after discharge. The hematology-oncology service was consulted in 5/62 (8.1%) cases and recommended testing in only 1 (1.6%) patient. Only 1 (1.6%) patient had both an appropriate indication and appropriate testing. Costs for the 273 total tests were $26,400.

Conclusion: Thrombophilia tests were often ordered inappropriately and unnecessarily. We recommend testing only for patients with inpatient status under recommendation from the hematology-oncology service.

Long term prognosis of acute pulmonary embolism

BACKGROUND

Acute pulmonary embolism (PE) can be fatal if left untreated. Long-term prognosis of acute PE in the 21st century has not been fully reported. We aimed to determine the long-term prognosis of patients hospitalized with acute PE and compare survivalof patients with idiopathic and secondary PE.

MATERIALS AND METHODS

We retrospectively analysed a cohort of hospitalized patients with acute PE between 2006 and 2013.

EXCLUSION CRITERIA

<18 years, venous embolism of non-pulmonary veins, chronic thromboembolic pulmonary hypertension, and presumptive diagnosis without image confirmation. Only patients with a first PE episode were included. End-point: all-cause mortality. Patients were compared according to PE aetiology: idiopathic, secondary to neoplastic conditions and secondary to non-neoplastic conditions. A Cox-regression analysis was used to study the prognostic impact of PE aetiology.

RESULTS

We studied 872 hospitalized acute PE patients. Median age 70 years, 56.9% were women. PE was idiopathic in 376 (43.1%), secondary to a neoplastic condition in 284 (32.6%) and secondary to a condition other than neoplasia in 212 (24.3%). Patients were followed for a median 25 months period and 508 (58.3%) died. Patients with PE attributed to a neoplastic condition had the worst survival. Patients with idiopathic PE had a multivariate-adjusted HR of mortality of 1.46 (1.08-1.99) during the over 2-year follow-up period when compared to those with acute PE attributed to a non-neoplastic condition.

CONCLUSIONS

Patients with idiopathic acute PE have an almost 50% higher death risk in a median 2-year follow-up period than those with acute PE secondary to a condition other than neoplasia.

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.