This blog posts summarizes key points on deep vein thrombosis (DVT) including scoring tools, investigations and management.
1. Approach to Edema
We first discussed approach to edema, which may be the first presenting symptom in a patient with an extremity deep vein thrombosis.
If edema is unilateral and acute consider your clinical probability of DVT and whether you want to investigate for this. See below for scoring tools and what investigations to send based on probability.
If edema is unilateral and chronic and there is a history of malignancy/trauma/pelvic surgery consider tumor obstruction or thrombus. If no history of cancer/trauma/pelvic surgery then think about other systemic causes.
2. Scoring Tools (Well’s and Constans score) and Investigations
*Remember that there is the PERC rule and if PERC=0 you can rule out VTE. If any one of PERC are present, you cannot so use that so then would use Well’s to risk stratify. There is also a Well’s score for PE which is separate from below.
The Well’s score for DVT can be used for lower limb DVT to calculate your pre-test probability and next steps. Acronym “BATS SLEEP I” and each of these gives you 1 point in the Well’s score, and you should minus 2 points from your score for an alternative likely diagnosis.
|Bedridden > 3 d or surgery within 4 weeks|
|CAncer (active) < 6 months|
|Tenderness along deep veins|
|Superficial veins (non varicose)|
|Swelling of calf > 3cm (10 cm below tib. Tub.)|
|Leg swollen (entire)|
|Evident collateral veins|
|Previously documented VTE|
|Immobilization of lower limb (or paralysis, paresis, or recent plaster immobilization)|
|Minus 2 for alternative likely diagnosis|
Scoring of Wells:
– High probability >= 3 points
– Moderate probability 1-2 points
– Low probability: 0 or less
For lower extremity DVT as per the American Society of Hematology Guidelines (ASH, 2018):
- Start with D-dimer for excluding DVT in a population with low prevalence/PTP (≤10%), followed by proximal lower extremity ultrasound or whole-leg ultrasound for patients requiring additional testing.
- If D-dimer is not readily available, alternate acceptable strategies include performing proximal lower extremity or whole-leg ultrasound alone.
- Whole-leg ultrasound, or starting with proximal lower extremity ultrasound for evaluating patients suspected of having DVT in a population with intermediate prevalence/PTP (∼25%).
- No further testing is required if the whole-leg ultrasound is negative, but a negative initial proximal ultrasound should be followed by serial proximal ultrasound if no alternative diagnosis is identified.
- Similar approach to intermediate, if a patient is high risk
The Constans score can be used for upper extremity DVT (UEDVT) risk assessment.
|Central venous catheter or pacemaker||+1 point|
|Localized pain||+1 point|
|Unilateral edema||+1 point|
|Another diagnosis being at least as plausible as UEDVT||-1 point|
Score <=1 UEDVT unlikely
Score >= 2 points or more classifies a patient as ‘UEDVT likely’
As per the American Society of Hematology (2018) guidelines:
- Low prevalence/unlikely pre-test probability for Upper Extremity DVT (10%):
- Suggests D-dimer for excluding upper extremity DVT in a population with low prevalence/unlikely PTP (10%), followed by duplex ultrasound if D-dimer is positive. If D-dimer is not readily available, performing duplex ultrasound alone is acceptable.
- High prevalence/likely pre-test probability for Upper Extremity DVT(40%)
- The ASH guideline panel suggests a strategy of either D-dimer followed by duplex ultrasound/serial duplex ultrasound, or duplex ultrasound/serial duplex ultrasound alone for assessing patients suspected of having upper extremity DVT in a population with high prevalence/likely PTP (40%).
3. Management of DVT
- Options for anticoagulation include unfractionated heparin, Low-molecular weight heparin, DOACs, warfarin (Need to consider bleed risk, contraindications, drug interactions, renal function – details not discussed here)
- Duration is at minimum three months
- Massive DVT is defined as iliofemoral thrombosis with severe symptoms, including phlegmasia cerulea dolens (severe cyanosis and swelling of the affected leg).
- When there is vascular compromise, the benefits of more rapid thrombus resolution may outweigh the risk of harm (CHEST 2021) i.e. may consider catheter-directed thrombolysis. The impact of catheter-directed thrombolysis on preventing post-thrombotic syndrome is controversial.
4. Upper Extremity DVT (UEDVT) and catheter-associated DVT
- Treatment should generally follow the principles for lower extremity DVT.
- Thrombolysis may be considered on a case-by-case basis for patients with upper extremity DVT with limb compromise
- Effort thrombosis and thoracic outlet syndrome should be considered as secondary causes.
- Removal of the central venous catheter is not required if it is still needed, functioning properly, and not associated with infection; however, if symptoms persist or worsen despite anticoagulation, the central venous catheter may need to be removed.
- It is reasonable to treat patients with a DVT in the axillary or a more proximal upper extremity deep vein for a minimum of 3 months or longer if the catheter remains in place.
- The Catheter 2 study for instance has shown that rivaroxaban monotherapy in 70 cancer patients with UEDVT catheter-related had a recurrence rate of 1.4% with one fatal PE and a bleeding rate of 12.9% at 12 weeks.
- Individualized discussions with patients should occur to pick the optimal therapy for treatment of catheter-associated UEDVT.
5. Duration of Treatment
- At minimum 3 months with provoked risk factor
- 6 months may be preferred if
- DVT/PE was very large or very symptomatic
- Symptoms of the initial DVT or PE persist
- Patient is not ready to stop anticoagulant therapy at 3 months, AND
- Patient does not have a high risk for bleeding.
- If provoked by cancer
- Extended anticoagulation (recommended if low-mod bleeding risk, suggested if high bleeding risk)
|Category of Transient Risk Factor||Examples of Risk Factors|
|MAJOR||– Surgery with general anesthetic (GA) >= 30 minutes|
– Admission with confinement to bed for at least 3 days
|MINOR||– Surgery with GA < 30 minutes|
– Admission to hospital for less than 3 days
– Confined to bed OUT of hospital for at least three days with acute illness
– Hormonal therapy
– Pregnancy or post-partum
– Leg injury associated with immobility for at least 3 days
Patients with a first episode of unprovoked VTE should receive at least 3 months of anticoagulation.
HERDOO2 scoring tool and others that are used to determine duration. All men have high risk of recurrence and should continue. Women score >=2 on HERDOO2 should continue. HERDOO2 rule includes post-thrombotic signs (hyperpigmentation, edema, erythema), D-Dimer >= 250 ug/L during anticoagulation, BMI >= 30 kg/m^2, Age >= 65 years. Another scoring tool to use when determining duration of treatment in women is DODS (D-Dimer Optimal Duration Study).
The decision to continue anticoagulation longer is based on the estimated risk of recurrence, the risk of bleeding, and patient preference.
6. Other DVT pearls
- Recommend against the use of IVC filter in addition to anticoagulation
- Suggest not using compression stockings routinely to prevent post-thrombophlebitic syndrome
- Thrombosis Canada has specific guidance on management of distal DVT which refers to vein thrombosis distal to popliteal vein. Anticoagulation may be withheld in favour of serial imaging to assess for proximal extension. Anticoagulation is suggested if: severe symptoms, risk factors for extension (thrombus > 5 cm in length, multiple deep veins involved, close to popliteal vein, no reversible risk factors, previous VTE, inpatient, active cancer, positive D-dimer), unable to return for serial studies, progression of DVT on repeat imaging
- A Cochrane Systematic Review (noted in the references section below, titled “Treatment of distal deep vein thrombosis (Review)”, concluded that patients treated with anticoagulation therapy (VKA) compared to placebo had reduced risk of recurrent VTE and recurrent DVT; little or no difference in major bleeding compared to no intervention or placebo, though there was an increase in clinically relevant non-major bleeding.
- Factors to consider in managing distal DVT are risk of progression on balance of bleeding.
7. Superficial Vein Thrombosis
There is specific guidance on superficial thrombophlebitis/superficial vein thrombosis on Thrombosis Canada.
- If there is a concomitant DVT, manage with therapeutic anticoagulation
- Isolated SVT which extends to within 3 cm of the saphenofemoral junction (SFJ): management is anticoagulate 3 months
- Isolated SVT ≥5 cm in length located >3 cm from the SFJ should receive prophylactic doses of fondaparinux (2.5 mg subcutaneously per day), rivaroxaban 10 mg po daily or prophylactic/intermediate doses of LMWH for 45 days, NSAID’s. compresses
- Isolated SVT <5 cm in length located >3 cm from the SFJ can be treated with oral or topical NSAIDs and compresses
- EXCEPT severe symptoms or risk factors for extension (prior history of DVT/PE or SVT, cancer, pregnancy, hormonal therapy, recent surgery or trauma)
- Prophylactic doses of fondaparinux (2.5 mg subcutaneously per day), prophylactic doses of rivaroxaban (10 mg po daily) or prophylactic/intermediate doses of LMWH for up to 45 days can be considered.
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- CHEST 2021 guidelines – https://journal.chestnet.org/article/S0012-3692(21)01507-5/fulltext?_ga=2.2803891.204732221.1646971323-1271491338.1646971323
- Thrombosis Canada Clinical Guides: https://thrombosiscanada.ca/clinicalguides/#
- ASH 2018 Diagnosis of VTE: https://ashpublications.org/bloodadvances/article/2/22/3226/16134/American-Society-of-Hematology-2018-guidelines-for?searchresult=1
- CHEST 2016: https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2016/03/02/15/45/antithrombotic-therapy-for-vte-disease
- CHEST 2012: https://journal.chestnet.org/article/S0012-3692(12)60129-9/pdf
- Well’s for DVT: https://www.mdcalc.com/wells-criteria-dvt
- Constans for UEDVT: https://practical-haemostasis.com/Clinical%20Prediction%20Scores/Formulae%20code%20and%20formulae/Formulae/Upper-limb-thromboses/Constans_score.html
- Kirkilesis G, Kakkos SK, Bicknell C, Salim S, Kakavia K. Treatment of distal deep vein thrombosis. Cochrane Database of Systematic Reviews 2020, Issue 4. Art. No.: CD013422. DOI: 10.1002/14651858.CD013422.pub2.