Policy Guidelines
Background
Venous thromboembolism, including deep vein thrombosis, pulmonary embolism, or both, affects an estimated 300 000 to 600 000 individuals in the United States annually resulting in significant morbidity and mortality (Gupta, Sarode, & Nagalla, 2017). The etiology of thrombosis is multifactorial, thus determination of risk is challenging.
Hypercoagulability can be acquired or hereditary. Inherited risk factors include genetic mutation of the coagulation system. Known loss of function mutations include those affecting antithrombin (AT), protein C (PC) and protein S (PS) Gain of function mutations include the factor V Leiden (FVL) and the prothrombin gene 20210 A/G (PGM) mutations (Stevens et al., 2016). VTE has a strong genetic basis, with approximately 50–60% of the variance in VTE incidence attributed to genetic effects(Crous-Bou, Harrington, & Kabrhel, 2016). Although patients with inherited thrombophilia have an increased relative risk of a first VTE, assessing the risk of recurrent VTE is the same in patients with and those without inherited thrombophilia (Connors, 2017). Acquired risk factors or predisposing conditions for thrombosis include a prior thrombotic event, recent major surgery, presence of a central venous catheter, trauma, immobilization, malignancy, pregnancy, the use of oral contraceptives or heparin, myeloproliferative disorders, antiphospholipid syndrome (APS), and a number of other major medical illnesses(Bauer & Lip, 2018). Patients with acquired hypercoagulability have an increased risk of venous thrombosis, arterial thrombosis, or both, however, have a low risk of recurrence, regardless of thrombophilia status(Connors, 2017).
Kudo et al (2016) evaluated the utility of thrombophilia testing and concluded “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.”
Recent review by Connnors (2017) states that “Although thrombophilia status is often used in making decisions about secondary prophylaxis after a first provoked VTE or about primary prophylaxis in positive family members at times of added or increased risk, data supporting this practice are limited. There are no data suggesting that patients with VTE and inherited thrombophilia should be treated differently from those who have VTE without thrombophilia; both groups should benefit from the use of VTE prophylaxis at times of increased major risk. A randomized, controlled trial addressing the question of whether testing for inherited thrombophilia at the time of a first VTE alters the risk of recurrence was stopped early because of low enrollment and lack of funding”.
Gupta et al (2017) concur stating that “Inherited thrombophilias may be more common in selected patients with unprovoked VTE, including those younger than 45 years, or those with a family history of VTE at young age. Even in these selected populations, inherited thrombophilia testing should not routinely change management of anticoagulation, although it may allow genetic counseling and testing of first-degree relatives.”
Applicable Federal Regulations
N/A
Guidelines and Recommendations
The American College of Medical Genetics and Genomics (ACMG) (Grody, Griffin, Taylor, Korf, & Heit, 2001; Spector et al., 2005)
Guidelines indicate that testing should be performed in at least the following circumstances (these are the same general recommendations for testing for any thrombophilia):
- Age <50, any venous thrombosis.
- Venous thrombosis in unusual sites (such as hepatic, mesenteric, and cerebral veins).
- Recurrent venous thrombosis.
- Venous thrombosis and a strong family history of thrombotic disease.
- Venous thrombosis in pregnant women or women taking oral contraceptives.
- Relatives of individuals with venous thrombosis under age 50.
- Myocardial infarction in female smokers under age 50.
Testing may also be considered in the following situations:
- Venous thrombosis, age >50, except when active malignancy is present.
- Relatives of individuals known to have factor V Leiden. Knowledge that they have factor V Leiden may influence management of pregnancy and may be a factor in decision making regarding oral contraceptive use.
- Women with recurrent pregnancy loss or unexplained severe preeclampsia, placental abruption, intrauterine fetal growth retardation, or stillbirth. Knowledge of factor V Leiden carrier status may influence management of future pregnancies.
Random screening of the general population for factor V Leiden is not recommended.
Routine testing is not recommended for patients with a personal or family history of arterial thrombotic disorders (e.g., acute coronary syndromes or stroke) except for the special situation of myocardial infarction in young female smokers. Testing may be worthwhile for young patients (<50 years of age) who develop acute arterial thrombosis in the absence of other risk factors for atherosclerotic arterial occlusive disease.
Neither prenatal testing nor routine newborn screening is recommended.
In contrast to the factor V Leiden recommendations, the ACMG does not support testing for MTHFR mutations “as part of the clinical evaluation for thrombophilia or recurrent pregnancy loss” or for “at-risk family members.”
The American College of Obstetricians and Gynecologists (ACOG, 2013)
Clinical management guidelines recommend that screening for inherited thrombophilia “may be considered in the following clinical settings:
- “A personal history of venous thromboembolism that was associated with a non-recurrent risk factor
- “A first degree relative (parent or sibling) with a history of high-risk thrombophilia.”
ACOG does not recommend “testing for inherited thrombophilias in women who have experienced recurrent fetal loss or placental abruption … because it is unclear if anticoagulation reduces recurrence.” Additionally, ACOG does not support testing for inherited thrombophilia in women with a history of preeclampsia or fetal growth restriction.
ACOG recommends that screening for inherited thrombophilias should include testing for “factor V Leiden mutation; prothrombin G20210A mutation; and antithrombin, protein C, and protein S deficiencies.” Also, it is recommended that testing be performed “(after 6 weeks) from the thrombotic event and while the patient is not pregnant and not taking anticoagulation or hormonal therapy.”
ACOG (Hickey, Curry, & Toriello, 2013) does not support testing for MTHFR variants, due to the lack of correlation with negative pregnancy outcomes.
EGAPP (Evaluation of Genomic Applications in Practice and Prevention) (EGAPP, 2011)
Recommendation
“The Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found adequate evidence to recommend against routine testing for Factor V Leiden (FVL) and/or prothrombin 20210G>A (PT) in the following circumstances: (1) adults with idiopathic venous thromboembolism (VTE). In such cases, longer term secondary prophylaxis to avoid recurrence offers similar benefits to patients with and without one or more of these mutations. (2)
Asymptomatic adult family members of patients with VTE and an FVL or PT mutation, for the purpose of considering primary prophylactic anticoagulation. Potential benefits are unlikely to exceed potential harms. The evidence was insufficient to determine whether FVL/PT testing might have clinical utility in some circumstances, such as for identifying FVL homozygosity among asymptomatic family members of adults with idiopathic VTE or counseling patients about the risks and benefits of antithrombotic therapy. The recommendations do not extend to patients with other risk factors for thrombosis, such as contraceptive use, as the evidence review that serves as the basis for the recommendations focused primarily on idiopathic VTE."
American Society of Hematology (ASH, 2013)
Recommend that: “Thrombophilia testing is costly and can result in harm to patients if the duration of anticoagulation is inappropriately prolonged or if patients are incorrectly labeled as thrombophilic. Thrombophilia testing does not change the management of VTEs occurring in the setting of major transient VTE risk factors. When VTE occurs in the setting of pregnancy or hormonal therapy, or when there is a strong family history plus a major transient risk factor, the role of thrombophilia testing is complex and patients and clinicians are advised to seek guidance from an expert in VTE.”
The Anticoagulation Forum published guidance in the Journal of Thrombosis and Thrombolysis on (Stevens et al., 2016):
- Do not perform thrombophilia testing following an episode of provoked VTE. A positive thrombophilia evaluation is not a sufficient basis to offer extended anticoagulation following an episode of provoked VTE.
- Do not perform thrombophilia testing in patients following an episode of unprovoked VTE. If a patient with unprovoked VTE and low bleeding risk is planning to stop anticoagulation, test for thrombophilia if test results would change this decision. A negative thrombophilia evaluation is not a sufficient basis to stop anticoagulants following an episode of unprovoked VTE in a patient with low bleeding risk and willingness to continue therapy. Heterozygosity for FVL or PGM does not increase the predicted risk of recurrence after unprovoked VTE to a clinically significant degree.
- Do not test for thrombophilia in asymptomatic family members of patients with VTE or hereditary thrombophilia. As a family history of VTE confers an excess risk of thrombosis, relatives should be counseled regarding use of prophylaxis in high risk situations.
- Do not test for thrombophilia in asymptomatic family members of patients with VTE or hereditary thrombophilia who are contemplating use of estrogen. If a woman contemplating estrogen use has a first-degree relative with VTE and a known hereditary thrombophilia, test for that thrombophilia if the result would change the decision to use estrogen.
- Do not perform thrombophilia testing at the time of VTE diagnosis or during the initial 3-month course of anticoagulant therapy. When testing for thrombophilia following VTE, use either a 2-stage testing approach (see text) or perform testing after a minimum of 3 months of anticoagulant therapy has been completed, and anticoagulants have been held.
Pregnancy, sex and estrogen use reduce the levels of Protein S. Use of sex specific reference intervals, and testing prior to pregnancy or while not receiving estrogen preparations is preferred.
Recent guidance published in the New England Journal of medicine by Gupta was summarized by Barnes for the American College of Cardiology:
- “Venous thromboembolism (VTE) affects an estimated 300,000-600,000 patients annually in the United States.
- The risk of VTE recurrence is best predicted by whether the initial VTE episode was provoked or unprovoked, not the results of inherited thrombophilia testing.
- Most patients with a provoked VTE have recently undergone surgery, immobility, trauma, or have a concurrent cancer diagnosis. Concurrent use of hormones (e.g., estrogencontaining contraceptive pills) is also frequently considered a provoking factor for VTE development.
- For patients with a first provoked VTE event, guidelines recommend anticoagulation for only 3 months (not longer). Prolonged anticoagulation is associated with an increased risk of bleeding that outweighs the risk of VTE recurrence for these patients.
- Patients with an unprovoked VTE (none of the provoking risk factors listed above) require longer anticoagulation due to a higher risk of recurrence that outweighs the risk of bleeding associated with long-term anticoagulation therapy.
- Thrombophilia testing performed in the setting of an acute clot or ongoing anticoagulation therapy will often result in spurious results (usually false positive). For example, natural anticoagulants (e.g., protein C and S, antithrombin) are consumed during an acute thrombotic event and the levels can be reduced by ongoing anticoagulant therapy.
- A recent study identified that up to 55% of Medicare patients with provoked VTE had undergone inappropriate thrombophilia testing, associated with significant cost to the healthcare system.
- While thrombophilia testing rarely impacts management decisions about anticoagulation therapy, it may be beneficial for genetic testing purposes in patients presenting with a first unprovoked VTE at a young age (e.g., <45 years) or at an unusual site.
- For patients with unprovoked VTE at a young age, VTE at an unusual site, arterial thrombosis, or pregnancy morbidity, testing for antiphospholipid antibodies, JAK2 mutation, and paroxysmal nocturnal hemoglobinuria may be beneficial.
- There is no role for extensive cancer screening (e.g., computed tomography scanning) in patients with VTE. Only routine, age-appropriate cancer screening is recommended.”