Thrombophilia testing, recurrent thrombosis, and women's health

Thrombophilia, Inflammation, and Recurrent Pregnancy Loss: A Case-Based Review

Recurrent pregnancy loss (RPL) is defined as the loss of two or more pregnancies and is often multifactorial with the majority of miscarriages being due to aneuploidy and anatomic or physiological abnormalities. However, inherited or acquired thrombophilias have also been associated with RPL, albeit inconsistently. While inherited thrombophilias, such as factor V Leiden and prothrombin gene mutation, are relatively prevalent in women with RPL compared with the general population, a causal link has yet to be definitively established. Recently, systemic inflammation, as measured by high-sensitivity C-reactive protein, has also been hypothesized to play a role in infertility. Based on limited prospective trial data, antithrombotic therapy and antiplatelet agents have been proposed as possible tools for the prevention of RPL. Because of the multifactorial nature of RPL and infertility, various clinicians, as obstetricians and gynecologists, endocrinologists, hematologists, or vascular medicine specialists, may be requested to counsel these women. This, together with evidence gaps, frequently leads to distinctly different diagnostic and therapeutic recommendations, especially regarding thrombophilia testing and treatment. Using four case vignettes in this review, we critically appraise the literature and highlight how two clinicians from different subspecialties approach the relationship between RPL, inflammation, and thrombophilia.

Comparative efficacy and safety of low-intensity warfarin therapy in preventing unprovoked recurrent venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

Although there exists potential risk of bleeding, extended 'lifelong' conventional-intensity [international normalized ratio (INR): 2.0-3.0] warfarin anticoagulation is recommended for unprovoked venous thromboembolism (VTE) patients because of risk of recurrent VTE. Whether long-term low-intensity (INR: 1.5-2.0) warfarin therapy reduced the risk of major bleeding without substantially lowered antithrombotic efficacy is not well understood. The aim of this study was to perform a systematic review and meta-analysis to evaluate the risk-benefits of low-intensity warfarin therapy.

METHODS

We conducted a comprehensive search of electronic databases and included randomized control trials (RCTs) that reported efficacy (recurrent VTE) and safety (bleeding episodes) of low-intensity warfarin therapy compared with conventional-intensity warfarin or placebo from inception through Jun 2016.

RESULTS

Four RCTs reporting high GRADE quality evidence were included. Although the relative risk of recurrent VTE with low-intensity therapy was significantly increased [2.96 (95% CI: 1.40 to 6.24), P < .004] compared to conventional-intensity warfarin, there was significant decrease of relative risk when compared with placebo [0.37 (95% CI: 0.24 to 0.56), P < .00001]. As per included publications, no significant major bleeding episodes were observed in low-intensity warfarin group.

CONCLUSIONS

Although less effective than conventional-intensity warfarin therapy this meta-analysis indicates that long-term low-intensity warfarin therapy is highly effective for preventing recurrent VTE than placebo, along with reduced risks of major bleeding and minimizing potential complications.

Rivaroxaban as an effective alternative to warfarin in a patient with atrial fibrillation, thrombophilia, and left atrial appendage thrombus: a case report

Background

Atrial fibrillation is the most common cardiac arrhythmia. It is responsible for up to 20% of all ischemic strokes. Rate control and anticoagulation are crucial for atrial fibrillation management and stroke prevention.

Case presentation

We present the case of an 84-year-old Italian woman with a left atrial appendage thrombus that developed despite her use of anticoagulant therapy with warfarin for a previous pulmonary embolism. She had atrial fibrillation and heterozygosity for both factor V Leiden and methylenetetrahydrofolate reductase C677T mutation, thus creating resistance to activated protein C. Anticoagulant therapy was switched to heparin for 1 week and then to rivaroxaban. After 3 months of rivaroxaban use, the thrombus disappeared.

Conclusions

This case raises the issue of the ineffectiveness of warfarin therapy in complex cases involving particular thrombophilic conditions and the possibility of using rivaroxaban as a safe and effective alternative.

Outcome of Patients with Venous Thromboembolism and Factor V Leiden or Prothrombin 20210 Carrier Mutations During the Course of Anticoagulation

BACKGROUND

Individuals with factor V Leiden or prothrombin G20210A mutations are at a higher risk to develop venous thromboembolism. However, the influence of these polymorphisms on patient outcome during anticoagulant therapy has not been consistently explored.

METHODS

We used the Registro Informatizado de Enfermedad TromboEmbólica database to compare rates of venous thromboembolism recurrence and bleeding events occurring during the anticoagulation course in factor V Leiden carriers, prothrombin mutation carriers, and noncarriers.

RESULTS

Between March 2001 and December 2015, 10,139 patients underwent thrombophilia testing. Of these, 1384 were factor V Leiden carriers, 1115 were prothrombin mutation carriers, and 7640 were noncarriers. During the anticoagulation course, 160 patients developed recurrent deep vein thrombosis and 94 patients developed pulmonary embolism (16 died); 154 patients had major bleeding (10 died), and 291 patients had nonmajor bleeding. On multivariable analysis, factor V Leiden carriers had a similar rate of venous thromboembolism recurrence (adjusted hazard ratio [HR], 1.16; 95% confidence interval [CI], 0.82-1.64), half the rate of major bleeding (adjusted HR, 0.50; 95% CI, 0.25-0.99) and a nonsignificantly lower rate of nonmajor bleeding (adjusted HR, 0.66; 95% CI, 0.43-1.01) than noncarriers. Prothrombin mutation carriers and noncarriers had a comparable rate of venous thromboembolism recurrence (adjusted HR, 1.00; 95% CI, 0.68-1.48), major bleeding (adjusted HR, 0.75; 95% CI, 0.42-1.34), and nonmajor bleeding events (adjusted HR, 1.10; 95% CI, 0.77-1.57).

CONCLUSIONS

During the anticoagulation course, factor V Leiden carriers had a similar risk for venous thromboembolism recurrence and half the risk for major bleeding compared with noncarriers. This finding may contribute to decision-making regarding anticoagulation duration in selected factor V Leiden carriers with venous thromboembolism.

Utility of thrombophilia testing in patients with venous thrombo-embolism

BACKGROUND

Clinical practice of thrombophilia testing those with venous thrombo-embolism (VTE) in public hospitals may not be consistent with the international guidelines. This study aims to assess whether practice of thrombophilia testing in two public hospitals are consistent with international guidelines, and to assess whether certain groups of patients were more likely to benefit from testing.

METHODS

A retrospective audit on patients who presented to two Queensland public hospitals from August 2011 to September 2012 with VTE. Data were collected on demographics, yield of the test, and whether the result of the test changed the duration of anticoagulation. Group analysis was performed to identify patients who were more likely to yield positive results.

RESULTS

Of the 152 patients, 49% were tested for thrombophilia, of whom 31% returned a positive result. 38% of patients with provoked VTE were tested for thrombophilia, inconsistent with guideline recommendations. In 1.2% of cases there were documented changes to duration of anticoagulation with positive results. The rates of positive results were 45% in unprovoked VTE cases compared with 29% in provoked VTE cases (P=0.054). The rates of positive results were 52% in recurrent VTE cases compared with 27% in those cases with first episode of VTE (P=0.007).

CONCLUSIONS

The practice of thrombophilia testing in public hospitals was frequently inconsistent with guidelines, and did not significantly influence clinical decisions. There was higher yield of testing in patients with recurrent episodes of VTE and possibly in patients with unprovoked VTE.

Efficacy of dabigatran versus warfarin in patients with acute venous thromboembolism in the presence of thrombophilia: Findings from RE-COVER®, RE-COVER™ II, and RE-MEDY™

It is unclear whether thrombophilia causes resistance to anticoagulant therapy. Post hoc analyses of data from RE-COVER®, RE-COVER™ II, and RE-MEDY™ were performed to compare dabigatran etexilate with warfarin for the treatment and prevention of venous thromboembolism (VTE) in patients with thrombophilia or antiphospholipid antibody syndrome (APS). There were no significant differences in symptomatic VTE/VTE-related deaths between dabigatran etexilate and warfarin in patients with or without thrombophilia. All bleeding event categories were less frequent with dabigatran etexilate than with warfarin, regardless of whether patients had thrombophilia, no thrombophilia, or were not tested. However, these differences did not reach significance in every group. In patients with APS, there was no significant difference in VTE/VTE-related deaths between the two treatment arms. Rates of bleeding events tended to be lower with dabigatran etexilate than with warfarin, reaching statistical significance for any bleeding event. In conclusion, the efficacy and safety of dabigatran etexilate were not significantly affected by the presence of thrombophilia or APS. ClinicalTrials.gov RECOVER Identifier: NCT00291330; RECOVER II Identifier: NCT00680186; RE-MEDY Identifier: NCT00329238

Use of decision aids for shared decision making in venous thromboembolism: A systematic review

BACKGROUND

Optimal care of patients with venous thromboembolism requires the input of patient preferences into clinical decision-making. However, the availability and impact of decision aids to facilitate shared decision making in care of venous thromboembolism is not well known.

OBJECTIVES

To assess the availability, clinical impact and outcomes associated with the use of decision aids in patients with or at risk for venous thromboembolism.

PATIENTS/METHODS

A systematic review of the literature was performed exploring the use of decision aids in patients with venous thromboembolism. Criteria for primary inclusion required use of patient values clarification in the decision aid. A secondary review without the requirement of a patient values clarification was performed to be more inclusive. The data was summarized such that knowledge gaps and opportunities for enquiry were identified.

RESULTS

The primary review identified one study that explored the decision to extend anticoagulation in patients with a recent venous thromboembolism beyond the stipulated 3-month duration. The secondary review identified an additional study exploring the decision to undergo computer tomography testing in patients at low risk for pulmonary embolism in an emergency department setting. Both studies were of modest quality given a lack of control group for comparison analysis.

CONCLUSIONS

Despite numerous calls to increase use of shared decision-making, a paucity of data exists to help patients engage in the treatment decisions for venous thromboembolism. Future studies of additional VTE clinical decisions with longer-term clinical outcomes appear necessary.

Embolic Strokes of Unknown Source and Cryptogenic Stroke: Implications in Clinical Practice

Up to a third of strokes are rendered cryptogenic or of undetermined etiology. This number is specifically higher in younger patients. At times, inadequate diagnostic workups, multiple causes, or an under-recognized etiology contributes to this statistic. Embolic stroke of undetermined source, a new clinical entity particularly refers to patients with embolic stroke for whom the etiology of embolism remains unidentified despite through investigations ruling out established cardiac and vascular sources. In this article, we review current classification and discuss important clinical considerations in these patients; highlighting cardiac arrhythmias and structural abnormalities, patent foramen ovale, paradoxical sources, and potentially under-recognized, vascular, inflammatory, autoimmune, and hematologic sources in relation to clinical practice.

Venous thromboembolism: Predicting recurrence and the need for extended anticoagulation

Initial treatment for venous thromboembolism (VTE) includes the acute and intermediate phases, usually lasting for 3 months. The choice to extend therapy beyond the initial 3-month window involves assessing a combination of risk factors for VTE recurrence and bleeding, along with weighing patient preferences. In some cases, such as VTE provoked by a reversible surgical risk factor, the recurrence risk is sufficiently low that most patients should not receive extended therapy. In other cases, such as VTE associated with malignancy, the recurrence risk is sufficiently high that treatment should be extended beyond the initial 3 months. However, a large number of patients fall into a grey zone where the decision on extended therapy is less clear-cut. In this review, we summarize the evidence for VTE recurrence risk and the role for extended anticoagulation given a variety of patient-specific factors and laboratory results. We also review the role of VTE risk prediction tools and provide a recommended algorithm for approaching the decision of extended anticoagulation therapy. Various agents available for extended VTE therapy, including warfarin, aspirin and the direct oral anticoagulant agents, are discussed.