Additional issues relating to duration of anticoagulant therapy for VTE
| Issues . | Considerations . |
|---|---|
| What is a reversible provoking factor? | The magnitude (or severity) of VTE risk factors, and the reversibility of risk factors, are on a continuum. Therefore, the distinction between a “trivial provoking factor” (consistent with being an unprovoked VTE) and a nonsurgical trigger (or minor reversible provoking factor) is arbitrary. We suggest that VTE can be considered provoked if there was a major reversible risk factor within 3 mo, or a minor reversible risk factor within 6 wk (eg, any general anesthesia; soft tissue injury that causes a limp; flight of >8 h; illness that renders the patient bed-bound for a day or chair-bound for 3 d). |
| Catheter-based thrombus removal | These patients should be treated for at least 3 mo. As the acute DVT is often severe, and symptoms may have become chromic (ie, PTS), anticoagulation for 6 mo is often desirable, and patients may be more likely to opt for indefinite anticoagulation if the DVT was provoked by a minor reversible risk factor. Placement of an iliac vein stent does not necessarily mean that patients should be treated indefinitely, but residual thrombus or extrinsic compression encourages that option. |
| Permanent vena cava filter | Vena cava filters appear to reduce PE and increase recurrent DVT.61 The presence of a permanent filter should not influence the duration of anticoagulant therapy. |
| Chronic thromboembolic pulmonary hypertension | These patients are generally treated with indefinite anticoagulation, whether or not they undergo endarterectomy or if known previous episodes of VTE were provoked by a reversible risk factor. |
| Hereditary thrombophilias | Hereditary thrombophilias are weak risk factors for recurrent VTE, although this is uncertain for antithrombin deficiency. Testing for hereditary thrombophilias in order to guide decisions about treatment duration does not appear to be justified. |
| Antiphospholipid antibodies | It is unclear if, independent of other clinical factors, an antiphospholipid antibody justifies indefinite anticoagulant therapy. For this reason, we do not routinely test for antiphospholipid antibodies in patients with VTE, including those with an unprovoked episode. |
| Inflammatory bowel disease | Inflammatory bowel disease (and probably other chronic inflammatory conditions) can serve as a persistent or intermittent risk factor for recurrent VTE.62 However, it is also possible that inflammatory bowel disease can serve as a reversible risk factor (eg, if it becomes inactive). |
| Estrogens | Estrogens serve as a reversible risk factor for VTE. It may be acceptable, however, for patients to remain on oral contraceptives during anticoagulant therapy.48 We then stop estrogen therapy at least a month before stopping anticoagulants. |
| Confidence to stop anticoagulants | It may take >3 mo for patients to be ready to consider stopping anticoagulant therapy. |
| Issues . | Considerations . |
|---|---|
| What is a reversible provoking factor? | The magnitude (or severity) of VTE risk factors, and the reversibility of risk factors, are on a continuum. Therefore, the distinction between a “trivial provoking factor” (consistent with being an unprovoked VTE) and a nonsurgical trigger (or minor reversible provoking factor) is arbitrary. We suggest that VTE can be considered provoked if there was a major reversible risk factor within 3 mo, or a minor reversible risk factor within 6 wk (eg, any general anesthesia; soft tissue injury that causes a limp; flight of >8 h; illness that renders the patient bed-bound for a day or chair-bound for 3 d). |
| Catheter-based thrombus removal | These patients should be treated for at least 3 mo. As the acute DVT is often severe, and symptoms may have become chromic (ie, PTS), anticoagulation for 6 mo is often desirable, and patients may be more likely to opt for indefinite anticoagulation if the DVT was provoked by a minor reversible risk factor. Placement of an iliac vein stent does not necessarily mean that patients should be treated indefinitely, but residual thrombus or extrinsic compression encourages that option. |
| Permanent vena cava filter | Vena cava filters appear to reduce PE and increase recurrent DVT.61 The presence of a permanent filter should not influence the duration of anticoagulant therapy. |
| Chronic thromboembolic pulmonary hypertension | These patients are generally treated with indefinite anticoagulation, whether or not they undergo endarterectomy or if known previous episodes of VTE were provoked by a reversible risk factor. |
| Hereditary thrombophilias | Hereditary thrombophilias are weak risk factors for recurrent VTE, although this is uncertain for antithrombin deficiency. Testing for hereditary thrombophilias in order to guide decisions about treatment duration does not appear to be justified. |
| Antiphospholipid antibodies | It is unclear if, independent of other clinical factors, an antiphospholipid antibody justifies indefinite anticoagulant therapy. For this reason, we do not routinely test for antiphospholipid antibodies in patients with VTE, including those with an unprovoked episode. |
| Inflammatory bowel disease | Inflammatory bowel disease (and probably other chronic inflammatory conditions) can serve as a persistent or intermittent risk factor for recurrent VTE.62 However, it is also possible that inflammatory bowel disease can serve as a reversible risk factor (eg, if it becomes inactive). |
| Estrogens | Estrogens serve as a reversible risk factor for VTE. It may be acceptable, however, for patients to remain on oral contraceptives during anticoagulant therapy.48 We then stop estrogen therapy at least a month before stopping anticoagulants. |
| Confidence to stop anticoagulants | It may take >3 mo for patients to be ready to consider stopping anticoagulant therapy. |