DVT & PE Flashcards by Sarah Gillen

Components of virchows triad

Vessel wall damage

Hypercoagulability

Altered blood flow (stasis)

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Hereditary deficiencies that lead to hypercoagulable state capable of producing DVT

Antithrombin deficiency
Protein C and S deficiency
Factor V Leiden mutation
Prothrombin 20210 gene mutation
Methylene tetrahydrofolate reductase deficiency (hyperhomocyteinemia)
Factor XII deficiency
Dysfibrogenemia

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Acquired disorders associated with recurrent venous or arterial thromboembolism

Protein C and S deficiency
Dysfibrogenemias
Antiphospholipid syndrome

[note: DSA puts C and S deficiency and dysfibrogenemias in “inherited” category; DSA lists acquired risk factors as cancer, pregnancy, OCPs, HRT, PRV, smoking, antiphospholipid syndrome, and chemotherapy]

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What is Homans sign

Pain in calf or popliteal area on dorsiflexion of the foot

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What is Moses sign (bancroft’s sign)

Pain caused by compression of the calf against the tibia bt not when squeezing the calf itself

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Lisker’s sign

Pain with percussion of the anteromedial tibia

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Lowenberg’s sign

BP cuff applied to mid calf and pain elicited with inflation to 80 mm Hg

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What sign might you see on visual inspection with someone with a lower extremity DVT?

Unilateral superficial venous distention — veins of affected leg distended in comparison to non-affected leg

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Wells criteria for DVT

Active cancer = +1

Bedridden recently >3 days or major surgery w/i 4 weeks = +1

Calf swelling >3cm compared to other leg = +1

Collateral (nonvaricose) superficial vv. present = +1

Entire leg swollen = +1

Localized tenderness along deep venous system = +1

Pitting edema confined to symptomatic leg = +1

Paralysis, paresis, or recent plaster immobilization of LE = +1

Previously documented DVT = +1

Alternative dx to DVT as likely or more likely = -2

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Scoring the wells criteria for DVT

0 = DVT unlikely

1-2 = moderate risk of DVT (proceed with high-sensitivity d-dimer testing)

3+ = DVT is likely

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List 5 major diagnostic tests that may be utilized for diagnosing DVT/PE

Contrast venography
Doppler venography
Ventilation/perfusion scan
CT pulmonary arteriography
D-dimer

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Pros/cons of the following for evaluation of DVT or PE:

Contrast venography

Pros:
Anatomic and luminal evaluation
Flow physiology (collaterals)

Cons:
Requires contrast (allergies, AKI)
Painful
Invasive

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Pros/cons of the following for evaluation of DVT or PE:

Doppler venography

Pros:
Inexpensive
Easy
No radiation
Flow physiology

Cons:
Tech dependent
Increased false positives/negatives

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Pros/cons of the following for evaluation of DVT or PE:

Ventilation/perfusion scan

Pros:
High sensitivity
Inexpensive

Cons:
Low specificity
May not demonstrate small sub-segmental defects

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Pros/cons of the following for evaluation of DVT or PE:

CT pulmonary angiography

Pros:
High sensitivity and specificity
Accurate anatomy assessment certainty
Often considered “gold standard” in intermediate risk cases

Cons:
Requires contrast
Expensive
Radiation exposure
May miss small peripheral clots

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Pros/cons of the following for evaluation of DVT or PE:

d-dimer

Pros:
Negative test makes DVT unlikely
Simple to perform

Cons:
Positive test is not diagnostic of DVT
Other conditions can elevate d-dimer

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Explain utility of D-dimer in dx of thromboembolic dz

Pts with low clinical likelihood of DVT should undergo testing with d-dimer as combination of a low clinical probability, and negative D-dimer rules out DVT

If a D-dimer is positive, or if clinical likelihood is high, then duplex ultrasonography should be performed

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Key differences between standard heparin and LMWH

LMWH allows for outpatient tx, lower risk of HIT

Key differences between heparin and warfarin

Longer term anticoagulation is usually with warfarin, which may be initiated simultaneously with heparin until INR reaches therapeutic range

Name a direct-acting oral anticoagulant that is an oral factor Xa inhibitor and clinical use

Rivaroxaban

Used after thromboembolic event and have rapid onset of action, do not require overlap with heparin, and have minimal interactions with food or other meds

Common complaints and clinical findings in pts with PE

Most common complaints are dyspnea, pleuritic chest pain, cough, and hemoptysis

Clinical findings may include tachypnea, crackles, tachycardia, and accentuated pulmonic component of S2

Wells criteria for PE

Clinical signs/symptoms of DVT = +3

Alternative diagnosis less likely than PE = +3

Heart rate >100bpm = +1.5

Immobilization >3days or surgery in past 4 wks = +1.5

Previous PE or DVT = 1.5

Hemoptysis = +1

Cancer = +1

[score: >6 = high risk, 2-6 = moderate risk, <2 = low risk]

Indications for thrombolytic therapy in pts with PE

PE with circulatory shock

PE with pulmonary HTN or right ventricular dysfunction

Commonly used anticoagulants in DVT and PE

IV unfractionated heparin may be used, but LMWH allows outpatient tx

Longer-term anticoagulation with warfarin

Newer oral anticoagulants include dabigatran, rivaroxaban, apixaban, and edoxaban — but are less reliably reversed

Once a pt with an acute DVT or PE is on stable anticoagulation, therapy should be continued for a duration based on risk factor profile. What is the baseline duration of anticoagulation prior to reassessing based on risk factors?

3 months

Following initial 3 months of anticoagulation therapy in a pt with acute DVT/PE, how long should anticoagulation therapy be continued if the initial event was due to a transient risk factor (e.g., major surgery, major trauma, major hospitalization)?

AC therapy likely can be discontinued at the 3-month mark, as long as there are no other risk factors present (assess on individual basis)

Following initial 3 months of anticoagulation therapy in a pt with acute DVT/PE, how long should anticoagulation therapy be continued if the initial event was cancer-related?

As long as the cancer is active

Following initial 3 months of anticoagulation therapy in a pt with acute DVT/PE, how long should anticoagulation therapy be continued if the initial event was unprovoked?

At least 3 months; consider indefinite if bleeding risk allows (ASA)

Following initial 3 months of anticoagulation therapy in a pt with acute DVT/PE, how long should anticoagulation therapy be continued if the pt has had recurrent unprovoked thromboembolic events?

Indefinitely

Following initial 3 months of anticoagulation therapy in a pt with acute DVT/PE, how long should anticoagulation therapy be continued if the initial event was due to an underlying thrombophilia (antiphospholipid antibody syndrome, inherited thrombophilias, >2 concomitant thrombophilic conditions)?

Indefinitely

Options for post-operative anticoagulation

LMWH (enoxaparin) Fondaparinux DOACs Warfarin [can also use unfractionated heparin but won’t be asked about it — just know that it can be used]

When is LMWH (enoxaparin) the anticoagulant of choice and how long is it administered?

Most medical pts and critical care pts Many surgical pts (4 weeks in abdominal/pelvic cancer surgery) Many ortho pts (10 day minimum; up to 1 month post-joint replacement in high risk pts) Bariatric surgery

When is Fondaparinux the anticoagulant of choice and how long is it administered?

Many orthopedic pts (10 day minimum; up to 1 month in high risk pts)

When are DOACs rivaroxaban or apixaban the anticoagulant of choice and how long is it administered?

Orthopedic pts s/p total knee or total hip replacement — give for 12 days following total knee replacement; give for 35 days following total hip replacement

DOAC dabigatran may be chosen for post-op anticoagulation in orthopedic pts s/p total hip replacement but can only be given if ....

Only given if CrCl is >30 ml/min [bc dabigatran is cleared by the kidney]

When is warfarin the anticoagulant of choice and how long is it administered?

A few orthopedic pts Goal INR is 2.5; give for 10 days minimum High risk pts s/p total hip or knee replacement or hip fracture may be on it for up to 1 month

Most common primary malignancies associated with DVT/PE

``` Lung Pancreas Colon/rectum Kidney Prostate ```

Drugs that cause hypercoagulability

Tamoxifen Bevacizumab Thalidomide, lenalidomide [note: thrombogenic effect lasts weeks after these are discontinued]

What makes heart failure a risk for thromboembolic dz?

Heart failure is a hypercoagulable state and is a major risk factor for intracardiac thrombi — reduced left ventricular function and afib The risk of DVT may be greatest in pts with right heart failure

Which of the following would lead to increased suspicion of a hypercoagulable disorder? ``` A. Evidence of DVT B. Pulmonary embolism C. Elevated d-dimer D. Family hx of thromboembolic dz E. Smoking ```

D. Family hx of thromboembolic dz

Which of the following is the best statement regarding the utility of the D-dimer? A. In pts thought to be unlikely to have PE, a normal D-dimer excludes PE and no further testing is required B. In pts thought to be likely to have PE, a normal D-dimer excludes PE and no further testing is required C. In pts thought to be unlikely to have PE, an elevated D-dimer confirms PE and no further testing is required D. In pts thought to be likely to have PE, an elevated D-dimer confirms PE and no further testing is required

A. In pts thought to be unlikely to have PE, a normal D-dimer excludes PE and no further testing is required [other things can affect D dimer levels! — stroke, increasing age, malignancy, pregnancy, recent surgery, DIC, cocaine use, CT disease, hemodialysis]

54 y/o man presents to ED for 1 hr hx of chest pain and SOB. He was hospitalized 1 wk ago for hemicolectomy for diverticular dz. PMH includes HTN with nephropathy. He is taking amlodipine, ramipril, and APAP prn. Exam reveals temp of 100, BP 110/60, pulse 115, RR 24, SaO2 89% on RA and 97% on 4L O2, cor tachy, LCTA, LLQ surgical incision healing well, CXR negative for infiltrates, widened mediastinum, pneumothorax, creatinine is 2.1 mg/dL. Most appropriate study to confirm his dx? A. CT angiography B. D-dimer assay C. LE doppler US D. V/P scanning

D. V/P scanning [dont do CT angiography bc creatinine is elevated and he cant have contrast; D-dimer will not be helpful bc may be artificially elevated in setting of nephropathy]

54 y/o man presents to ED for 1 hr hx of chest pain and SOB. He was hospitalized 1 wk ago for hemicolectomy for diverticular dz. PMH includes HTN with nephropathy. He is taking amlodipine, ramipril, and APAP prn. Exam reveals temp of 100, BP 110/60, pulse 115, RR 24, SaO2 89% on RA and 97% on 4L O2, cor tachy, LCTA, LLQ surgical incision healing well, CXR negative for infiltrates, widened mediastinum, pneumothorax, creatinine is 2.1 mg/dL. He is dx with a PE from DVT in left internal iliac v. After IV heparin and stabilization, he is preparing to leave the hospital. What is the best solution for outpatient anticoagulation? ``` A. Clopidogrel B. Rivaroxaban C. Enoxaparin D. Fondaparinux E. ASA + dipyridimole ```

C. Rivaroxaban [not enoxaparin bc it is cleared by the kidney and he has renal insufficiency; fondaparinux is a shot so oral med is better]

A 67 y/o M is preparing for a total knee replacement. He is not obese, and his only other health problem is osteoarthritis for which he takes ibuprofen OTC. What is the best recommendation for DVT prophylaxis? A. SCDs during hospitalization B. SCD + enoxaparin during hospitalization C. Enoxaparin alone during hospitalization D. Enoxaparin + SCD during hospitalization; completion of minimum of 10 days of enoxaparin as outpatient E. Enoxaparin alone for minimum of 10 days inpatient and outpatient

D. Enoxaparin + SCD during hospitalization; completion of minimum of 10 days of enoxaparin as outpatient