How I treat pregnancy-related venous thromboembolism

Massive deep vein thrombosis in pregnant women: The importance of individualizing the action plan

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a potentially lethal condition to be taken into account in pregnant women, where the situation is favored by the characteristic physiological changes of the pregnancy, childbirth and the puerperium. The management of this pathology in this type of patient is based on anticoagulation, with the benefits and drawbacks that this implies. We present the case of a pregnant woman with massive DVT and the issues are discussed, such as the method of delivery (vaginal vs. cesarean section) or the management of treatment (LMWH vs. UFH) in order to obtain the safest situation for the patient.

Management of anticoagulation in pregnant women with venous thromboembolism: An international survey of clinical practice

INTRODUCTION

Venous thromboembolism (VTE) is an important cause of maternal morbidity and mortality. During pregnancy, VTE is treated with low-molecular-weight-heparin (LMWH). Studies assessing the optimal duration and peripartum management of therapeutic anticoagulation are lacking. This survey aimed to assess clinician practices for the management of anticoagulation in pregnant women with acute VTE.

METHODS

An electronic survey consisting of clinical scenarios addressing anticoagulation management for VTE in pregnancy was created. The target sample was clinicians likely to be involved in the management of pregnant women with acute VTE. The survey completion rate and proportion of individuals selecting a response were determined.

RESULTS

96 respondents completed the survey including general internists (56.3%), hematologists (21.9%), and obstetricians (6.3%). In the management of a VTE in first or second trimester, most respondents preferred therapeutic LMWH until 6 weeks postpartum. In the first and second trimester, 48.0% and 37.5% of respondents, respectively, opted to reduce the dose of anticoagulation after 3 or 6 months. 29.2% of physicians opted for bridging with intravenous heparin around delivery when treating a VTE in the third trimester. 73.0% perceived an increased risk of clinically relevant non-major bleeding associated with the use of therapeutic anticoagulation in the peripartum and postpartum periods.

CONCLUSIONS

The survey highlights a wide variability of practice in the management of therapeutic anticoagulation in pregnancy. Larger scale studies with relevant clinical outcomes including thrombosis and bleeding risks are needed to inform clinical practice.

The role of echocardiography in amniotic fluid embolism: a case series and review of the literature

PURPOSE

Amniotic fluid embolism (AFE) is a rare, but often fatal condition characterized by sudden hemodynamic instability and coagulopathy occurring during labour or in the early postpartum period. As the mechanisms leading to shock and the cardiovascular effects of AFE are incompletely understood, the purpose of this case series is to describe how AFE presents on echocardiography and review limited reports in the literature.

CLINICAL FEATURES

We describe three cases of AFE at the Jewish General Hospital, a tertiary care centre in Montreal, Canada. All cases met the Clark diagnostic criteria, which comprise 1) sudden cardiorespiratory arrest or both hypotension and respiratory compromise, 2) disseminated intravascular coagulation, 3) clinical onset during labour or within 30 min of delivery of the placenta, and 4) absence of fever. Two patients had a cardiac arrest and the third developed significant hypotension and hypoxia. In all patients, point-of-care echocardiography at the time of shock revealed signs of right ventricular failure including a D-shaped septum, acute pulmonary hypertension, and right ventricular systolic dysfunction.

CONCLUSION

This case series and literature review of AFE emphasizes the importance of echocardiography in elucidating the etiology of maternal shock. The presence of right ventricular failure may be considered an important criterion to diagnose AFE.

A Narrative Review of the Complex Relationship between Pregnancy and Eye Changes

Pregnancy is a condition often characterized by changes that occur in different parts of the body. Generally, the eyes suffer several changes during pregnancy that are usually transient but may become permanent at times. This may occur due to the release of placental hormones and those of maternal endocrine glands and fetal adrenal glands. Due to hormonal influences, physiological ocular changes during pregnancy have been shown in Caucasian women, so corneal sensitivity, refractive status, intraocular pressure, and visual acuity may change during pregnancy. Within this review, all studies that referred to physiological aspects and to changes of ocular pathology of pregnancy, the effect of the pregnancy on pre-existing (diabetic retinopathy, neuro-ophthalmic disorders) eye disorders, postpartum ocular changes, the intraocular pressure and the effect of hypotensive ophthalmic medicine during pregnancy, the connection between pregnancy and the neuro-ophthalmic pathology, as well as the role of anesthesia were analyzed.

Second consensus document on diagnosis and management of acute deep vein thrombosis: updated document elaborated by the ESC Working Group on aorta and peripheral vascular diseases and the ESC Working Group on pulmonary circulation and right ventricular function

This consensus document is proposed to clinicians to provide the whole spectrum of deep vein thrombosis management as an update to the 2017 consensus document. New data guiding clinicians in indicating extended anticoagulation, management of patients with cancer, and prevention and management of post-thrombotic syndrome are presented. More data on benefit and safety of non-vitamin K antagonists oral anticoagulants are highlighted, along with the arrival of new antidotes for severe bleeding management.

How I treat venous thromboembolism in pregnancy

One to 2 pregnant women in 1000 will experience venous thromboembolism (VTE) during pregnancy or postpartum. Pulmonary embolism (PE) is a leading cause of maternal mortality, and deep vein thrombosis leads to maternal morbidity, with postthrombotic syndrome potentially diminishing quality of life for a woman's lifetime. However, the evidence base for pregnancy-related VTE management remains weak. Evidence-based guideline recommendations are often extrapolated from nonpregnant women and thus weak or conditional, resulting in wide variation of practice. In women with suspected PE, the pregnancy-adapted YEARS algorithm is safe and efficient, rendering computed tomographic pulmonary angiography to rule out PE unnecessary in 39%. Low molecular weight heparin (LMWH) in therapeutic doses is the treatment of choice during pregnancy, and anticoagulation (LMWH or vitamin K antagonists [VKAs]) should be continued until 6 weeks after delivery, with a 3-month minimum total duration. LMWH or VKA use does not preclude breastfeeding. Postpartum, direct oral anticoagulants are an option if a woman does not breastfeed and long-term use is intended. Management of delivery, including type of analgesia, requires a multidisciplinary approach and depends on local preferences and patient-specific conditions. Several options are possible, including waiting for spontaneous delivery with temporary LMWH interruption. Prophylaxis for recurrent VTE prevention in subsequent pregnancies is indicated in most women with a history of VTE.

Contemporary best practice in the management of pulmonary embolism during pregnancy

Approximately 1-2 per 1000 pregnancies are complicated by venous thromboembolism (VTE). VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE) and the diagnostic management of pregnancy-related VTE is challenging. Current guidelines vary greatly in their approach to diagnosing PE in pregnancy as they base their recommendations on scarce and weak evidence. The pregnancy-adapted YEARS diagnostic algorithm is well tolerated and is the most efficient diagnostic algorithm for pregnant women with suspected PE, with 39% of women not requiring computed tomographic pulmonary angiography. Low-molecular-weight heparin is the first-choice anticoagulant treatment in pregnancy and should be continued until 6 weeks postpartum and for a minimum of 3 months. Direct oral anticoagulants should be avoided in women who want to breastfeed. Management of delivery needs a multidisciplinary approach in order to decide on an optimal delivery plan. Neuraxial analgesia can be given in most patients, provided time windows since last low-molecular-weight heparin dose are respected. Women with a history of VTE are at risk of recurrence during pregnancy and in the postpartum period. Therefore, in most women with a history of VTE, thromboprophylaxis in subsequent pregnancies is indicated. The reviews of this paper are available via the supplemental material section.

Sex matters: Practice 5P's when treating young women with venous thromboembolism

Sex matters when it comes to venous thromboembolism (VTE). We defined 5P's - period, pill, prognosis, pregnancy, and postthrombotic syndrome - that should be discussed with young women with VTE. Menstrual blood loss (Period) can be aggravated by anticoagulant therapy. This seems particularly true for direct oral anticoagulants. Abnormal uterine bleeding can be managed by hormonal therapy, tranexamic acid, or modification of treatment. The use of combined oral contraceptives (Pill) is a risk factor for VTE. The magnitude of the risk depends on progestagen types and estrogen doses used. In women using therapeutic anticoagulation, concomitant hormonal therapy does not increase the risk of recurrent VTE. Levonorgestrel-releasing intrauterine devices and low-dose progestin-only pills do not increase the risk of VTE. In young women VTE is often provoked by transient hormonal risk factors that affects prognosis. Sex is incorporated as predictor in recurrent VTE risk assessment models. However, current guidelines do not propose using these to guide treatment duration. Pregnancy increases the risk of VTE by 4-fold to 5-fold. Thrombophilia and obstetric risk factors further increase the risk of pregnancy-related VTE. In women with a history of VTE, the risk of recurrence during pregnancy or post partum appears to be influenced by risk factors present during the first VTE. In most women with a history of VTE, antepartum and postpartum thromboprophylaxis with low-molecular-weight heparin is indicated. Women generally are affected by VTE at a younger age then men, and they have to deal with long-term complications (Post-thrombotic syndrome) of deep vein thrombosis early in life.

Pregnancy and Pulmonary Embolism

Venous thromboembolism (VTE), referring to both deep vein thrombosis and pulmonary embolism, is a leading cause of death in the developed world during pregnancy. This increased risk is attributed to the Virchow triad, inherited thrombophilias, along with other standard risk factors, and continues for up to 6 to 12 weeks postpartum. During the peripartum period, women should be risk stratified and preventive measures should be initiated based on their risk. Diagnostic tests and treatment strategies commonly used in VTE differ in pregnancy. An understanding of these differences is imperative to diagnose with confidence and to treat appropriately.

Pitfalls in the diagnostic management of pulmonary embolism in pregnancy

Women are at increased risk of venous thromboembolism (VTE) during pregnancy and VTE remains one of the main causes of maternal mortality in developed countries (Konstantinides SV, et al. Eur Heart J 2014; 35(43):3033-69, 69a-69k). Although an accurate diagnosis of acute pulmonary embolism (PE) in pregnant patients is thus of crucial importance, the diagnostic management of suspected PE is challenging for this specific patient category. As D-dimer levels increase physiologically throughout pregnancy, the optimal D-dimer threshold to rule out PE during pregnancy remains unknown. Available clinical decision rules, such as the Wells score and the revised Geneva rule, have not been evaluated in pregnant patients. Also, although ventilation-perfusion (V-Q) lung scan and computed tomography pulmonary angiography (CTPA) can be used in the pregnant population, both modalities have disadvantages of radiation exposure to both mother and foetus. Because of these uncertainties, clinical guidelines provide contradicting recommendations with weak levels of evidence. In this review, we illustrate these dilemmas and provide practice recommendation for the diagnostic management of suspected PE in pregnancy using two real-life patient cases.

Imaging for the exclusion of pulmonary embolism in pregnancy

BACKGROUND

Pulmonary embolism is a leading cause of pregnancy-related death. An accurate diagnosis in pregnant patients is crucial to prevent untreated pulmonary embolism as well as unnecessary anticoagulant treatment and future preventive measures. Applied imaging techniques might perform differently in these younger patients with less comorbidity and altered physiology, who largely have been excluded from diagnostic studies.

OBJECTIVES

To determine the diagnostic accuracy of computed tomography pulmonary angiography (CTPA), lung scintigraphy and magnetic resonance angiography (MRA) for the diagnosis of pulmonary embolism during pregnancy.

SEARCH METHODS

We searched MEDLINE and Embase until July 2015. We used included studies as seeds in citations searches and in 'find similar' functions and searched reference lists. We approached experts in the field to help us identify non-indexed studies.

SELECTION CRITERIA

We included consecutive series of pregnant patients suspected of pulmonary embolism who had undergone one of the index tests (computed tomography (CT) pulmonary angiography, lung scintigraphy or MRA) and clinical follow-up or pulmonary angiography as a reference test.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction and quality assessment. We contacted investigators of potentially eligible studies to obtain missing information. In the primary analysis, we regarded inconclusive index test results as a negative reference test, and treatment for pulmonary embolism after an inconclusive index test as a positive reference test.

MAIN RESULTS

We included 11 studies (four CTPA, five lung scintigraphy, two both) with a total of 695 CTPA and 665 lung scintigraphy results. Lung scintigraphy was applied by different techniques. No MRA studies matched our inclusion criteria.Overall, risk of bias and concerns regarding applicability were high in all studies as judged in light of the review research question, as was heterogeneity in study methods. We did not undertake meta-analysis. All studies used clinical follow-up as a reference standard, none in a manner that enabled reliable identification of false positives. Sensitivity and negative predictive value were therefore the only valid test accuracy measures.The median negative predictive value for CTPA was 100% (range 96% to 100%). Median sensitivity was 83% (range 0% to 100%).The median negative predictive value for lung scintigraphy was 100% (range 99% to 100%). Median sensitivity was 100% (range 0% to 100%).The median frequency of inconclusive results was 5.9% (range 0.9% to 36%) for CTPA and 4.0% (range 0% to 23%) for lung scintigraphy. The overall median prevalence of pulmonary embolism was 3.3% (range 0.0% to 8.7%).

AUTHORS' CONCLUSIONS

Both CTPA and lung scintigraphy seem appropriate for exclusion of pulmonary embolism during pregnancy. However, the quality of the evidence mandates cautious adoption of this conclusion. Important limitations included poor reference standards, necessary assumptions in the analysis regarding inconclusive test results and the inherent inability of included studies to identify false positives. It is unclear which test has the highest accuracy. There is a need for direct comparisons between diagnostic methods, including MR, in prospective randomized diagnostic studies.

Guidance for the treatment of deep vein thrombosis and pulmonary embolism

This guidance document focuses on the diagnosis and treatment of venous thromboembolism (VTE). Efficient, cost effective diagnosis of VTE is facilitated by combining medical history and physical examination with pre-test probability models, D dimer testing and selective use of confirmatory imaging. Clinical prediction rules, biomarkers and imaging can be used to tailor therapy to disease severity. Anticoagulation options for acute VTE include unfractionated heparin, low molecular weight heparin, fondaparinux and the direct oral anticoagulants (DOACs). DOACs are as effective as conventional therapy with LMWH and vitamin K antagonists. Thrombolytic therapy is reserved for massive pulmonary embolism (PE) or extensive deep vein thrombosis (DVT). Inferior vena cava filters are reserved for patients with acute VTE and contraindications to anticoagulation. Retrievable filters are strongly preferred. The possibility of thoracic outlet syndrome and May-Thurner syndrome should be considered in patients with subclavian/axillary and left common iliac vein DVT, respectively in absence of identifiable triggers. The optimal duration of therapy is dictated by the presence of modifiable thrombotic risk factors. Long term anticoagulation should be considered in patients with unprovoked VTE as well as persistent prothrombotic risk factors such as cancer. Short-term therapy is sufficient for most patients with VTE associated with transient situational triggers such as major surgery. Biomarkers such as D dimer and risk assessment models such the Vienna risk prediction model offer the potential to customize VTE therapy for the individual patient. Insufficient data exist to support the integration of bleeding risk models into duration of therapy planning.

Retinal artery and vein thrombotic occlusion during pregnancy: markers for familial thrombophilia and adverse pregnancy outcomes

Background

Ocular vascular occlusion (OVO), first diagnosed during or immediately after giving birth, often reflects superposition of the physiologic thrombophilia of pregnancy on previously undiagnosed underlying familial or acquired thrombophilia associated with spontaneous abortion, eclampsia, or maternal thrombosis.

Specific aim

We describe OVO, first diagnosed during pregnancy or immediately postpartum, in three young females (ages 32, 35, 40) associated with previously undiagnosed familial thrombophilia.

Results

Branch retinal artery occlusion (BRAO) occurred at 9 and 13 weeks gestation in two females, aged 32 and 35. Central retinal vein occlusion occurred immediately postpartum in a 40-year-old. One of the two females with BRAO subsequently developed eclampsia, and one had a history of unexplained first trimester spontaneous abortion. All three females were found to have previously unexplained familial thrombophilia. The two females with BRAO had low first trimester free protein S 42 (41%), lower normal limit (50%), and one of these two had high factor VIII (165%, upper normal limit 150%). The woman with central retinal vein occlusion had high factor XI (169%, upper normal limit 150%). Enoxaparin (40–60 mg/day) was started and continued throughout pregnancy in both females with BRAO to prevent maternal–placental thrombosis, and of these two females, one had an uncomplicated pregnancy course and term delivery, and the second was at gestational week 22 without complications at the time of this manuscript. There were no further OVO events in the two females treated with enoxaparin or in the untreated patient with postpartum eclampsia.

Conclusion

OVO during pregnancy may be a marker for familial or acquired thrombophilia, which confers increased thrombotic risk to the mother and pregnancy, associated with spontaneous abortion or eclampsia. OVO during pregnancy, particularly when coupled with antecedent adverse pregnancy outcomes, should prompt urgent thrombophilia evaluation and institution of thromboprophylaxis to prevent adverse maternal and fetal–placental thrombotic events.

Current challenges in diagnostic imaging of venous thromboembolism

Because the clinical diagnosis of deep-vein thrombosis and pulmonary embolism is nonspecific, integrated diagnostic approaches for patients with suspected venous thromboembolism have been developed over the years, involving both non-invasive bedside tools (clinical decision rules and D-dimer blood tests) for patients with low pretest probability and diagnostic techniques (compression ultrasound for deep-vein thrombosis and computed tomography pulmonary angiography for pulmonary embolism) for those with a high pretest probability. This combination has led to standardized diagnostic algorithms with proven safety for excluding venous thrombotic disease. At the same time, it has become apparent that, as a result of the natural history of venous thrombosis, there are special patient populations in which the current standard diagnostic algorithms are not sufficient. In this review, we present 3 evidence-based patient cases to underline recent developments in the imaging diagnosis of venous thromboembolism.

New studies of low-molecular-weight heparin in pregnancy

Several aspects of the diagnostic and therapeutic management of women with venous thrombosis are uncertain, because of the absence of adequately sized observational or intervention studies. Here, I will discuss the rationale and design of two currently ongoing investigator-initiated, international, randomized controlled trials of LMWHin pregnancy. The Highlow study (www.highlowstudy.org; NCT Clinicaltrials.gov) 01828697) investigates two doses of low-molecular-weight heparin to prevent recurrent venous thromboembolism (VTE) in pregnant women with a history of VTE. The ALIFE2 study (www.alife2study.org; www.trialregister.nl, NTR 3361) investigates the effect of LMWH on live birth in women with inherited thrombophilia and two or more miscarriages.

Current challenges in diagnostic imaging of venous thromboembolism

Because the clinical diagnosis of deep-vein thrombosis and pulmonary embolism is nonspecific, integrated diagnostic approaches for patients with suspected venous thromboembolism have been developed over the years, involving both non-invasive bedside tools (clinical decision rules and D-dimer blood tests) for patients with low pretest probability and diagnostic techniques (compression ultrasound for deep-vein thrombosis and computed tomography pulmonary angiography for pulmonary embolism) for those with a high pretest probability. This combination has led to standardized diagnostic algorithms with proven safety for excluding venous thrombotic disease. At the same time, it has become apparent that, as a result of the natural history of venous thrombosis, there are special patient populations in which the current standard diagnostic algorithms are not sufficient. In this review, we present 3 evidence-based patient cases to underline recent developments in the imaging diagnosis of venous thromboembolism.

[Venous thromboembolism and pregnancy]

Venous thromboembolism (VTE) is a major cause of maternal morbidity and mortality during or early after pregnancy. Prior VTE or family history of VTE, clinical or biological risk factors increased the risk of pregnancy-related VTE. Defining the risk of VTE before or at the beginning of pregnancy is necessary to propose the best prevention. However, the management is not standardized between physicians, centres and countries. Current guidelines for prophylaxis and treatment of VTE are discussed in this review.

Management of pregnancy associated venous-thromboembolism: a survey of practices

Introduction

Low-molecular-weight heparin (LMWH) is frequently recommended for the treatment of pregnancy associated venous thromboembolism (PAVTE). Given that prior reports have suggested a wide variation in dosing of LMWH in pregnancy and the use of anti-Xa monitoring in pregnancy, the principal aim of this survey was to assess current practices for the management of PAVTE.

Methods

An electronic survey was conducted. The target sample was members of the North American Society of Obstetric Medicine and Thrombosis Interest Group of Canada.

Results

The final sample consisted of 27/69 hematologists (39.1%), 30/69 internists (43.5%), 8/69 obstetricians (11.6%), and 4/69 from other specialties (5.7%). For the acute treatment of patients pregnant patients with deep vein thrombosis 42/69 (60.8%) preferred LMWH given twice a day 42/69 (60.8%), whereas 25/69 (36.2%) preferred once daily. These results were similar for patients with pulmonary embolism (PE). For long-term treatment more than 70% of the respondents favoured treatment with full doses of LMWH given once a day or twice a day and 16/69 (23.2%) intermediate doses for patients diagnosed with DVT. These results were similar for patients with PE. Fourteen physicians out of 69 (20.3%) did not measure anti-Xa monitoring during acute treatment period and 24/69 (34.8%) never used anti-Xa levels during the long term treatment period. Management during the peri-partum period varied widely according to the time of the diagnosis of PAVTE.

Discussion

In conclusion, our survey shows wide variation in practice regarding LMWH dosing and anti-Xa monitoring in pregnancy associated VTE and calls for trials comparing different long term strategies using LMWH in patients with PAVTE.

Intermediate doses of low-molecular-weight heparin for the long-term treatment of pregnancy thromboembolism. A systematic review

Note: The contact information for Drs. Gandara and Carrier is the same as for Dr. Rodger. Their e-mail addresses are egandara@ohri.ca and mcarrier@ohri.ca, respectively.

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.

Endovascular treatment of postpartum deep venous thrombosis: report of three cases

Pregnancy and the postpartum period are generally considered as contraindications for thrombolysis. We evaluate in this report the safety and effectiveness of using ultrasound-accelerated catheter-directed thrombolysis (UACDT) in treating three symptomatic postpartum deep vein thrombosis (DVT). UACDT was performed using a recombinant human tissue plasminogen activator (alteplase) which was delivered using the EKOS EkoSonic® system. Postprocedure venography was repeated after treatment which include stenting if stenosis was present. The treatment was successful in all three cases of iliofemoral DVT and symptom relief was achieved in all cases. Minor bleeding at the catheter insertion site in one patient was observed but none of the patients suffered from major bleeding or symptomatic pulmonary embolism. UACDT is a safe and effective treatment for restoration of the venous flow in patients with postpartum iliofemoral DVT. Residual venous obstruction should be treated by angioplasty and stent insertion to avoid early re-thrombosis.

Ultrasound-accelerated catheter-directed thrombolysis for the management of postpartum deep venous thrombosis

Pregnancy and the postpartum period are associated with an increased risk of venous thromboembolism, which remains an important cause of maternal morbidity and mortality. Although oral or systemic anticoagulation therapy may minimize thrombus propagation, it remains ineffective in removing thrombus burden and consequently does not prevent post-thrombotic syndrome. A novel technique, ultrasound accelerated catheter directed thrombolysis (UACDT), has been developed to rapidly and completely resolve thrombus. While pregnancy and the postpartum period are generally considered as contraindications for thrombolysis, we demonstrate in this case study the safety and effectiveness of using UACDT to treat symptomatic, postpartum, iliofemoral deep vein thrombosis after only an overnight infusion.

[Stereophotography of the ocular fundus. 2. Observation method]

Traditional anticoagulant agents such as vitamin K antagonists (VKAs), unfractionated heparin (UFH), low molecular weight heparins (LMWHs) and fondaparinux have been widely used in the prevention and treatment of thromboembolic diseases. However, these agents are associated with limitations, such as the need for regular coagulation monitoring (VKAs and UFH) or a parenteral route of administration (UFH, LMWHs and fondaparinux).

Several non-VKA oral anticoagulants (NOACs) are now widely used in the prevention and treatment of thromboembolic diseases and in stroke prevention in non-valvular atrial fibrillation. Unlike VKAs, NOACs exhibit predictable pharmacokinetics and pharmacodynamics. They are therefore usually given at fixed doses without routine coagulation monitoring. However, in certain patient populations or special clinical circumstances, measurement of drug exposure may be useful, such as in suspected overdose, in patients experiencing a hemorrhagic or thromboembolic event during the treatment’s period, in those with acute renal failure, in patients who require urgent surgery or in case of an invasive procedure. This article aims at providing guidance on laboratory testing of classic anticoagulants and NOACs.