VTE Flashcards
What are the components of the ‘thrombosis’ mnemonic for RF for VTE?
T: Trauma, Travel. H: Hormones R: Recreational drugs (IV) O: Old age (>60) M: Malignancy B: Birth control O: Obesity, obstetrics S: Surgery, smoking I: Immobilization S: Sickness (CHF, MI, nephoritc syndrome, IBD, etc)
Well’s DVT score: # pts per category and overall risk of DVT per category
Low risk: 0 pts, 5% likelihood DVT
Moderate risk: 1-2 pts, 33%
High risk: 3+ pts, 85% risk
Where in the venous system are symptomatic DVTs typically present?
At or proximal to popliteal vessels in >80% of cases. A calf DVT will extend proximally in only 20% of cases.
What are DVT well’s criteria (9)?
All 1 pt:
1) Active Ca
20 paralysis (paresis, recent plaster immobilization)
3) bed ridden >3d or Sx w/in 4 wks
4) localized tenderness along deep venous system
5) entire leg swollen
6) Calf swelling >3cm one side
7) Pitting edema confined to symptomatic leg
8) Collateral superficial veins (non-varicose)
- 2 pts if:
9) alternative Dx as likely or greater
Screening/diagnostic tools for DVT (5)
D-dimer, doppler US (duplex), contrast venography, CTV (CT venography), MR venography (MRV)
What is a ‘d-dimer’
Fragments of degradation products of fibrin. Elevated levels indicate activation of clotting mechanisms.
Only useful if test is negative
Which pts is D-Dimer testing useful for in r/o DVT?
Low-moderate risk (over 99% NPV)
What % of pts over 85 will have a positive D-dimer with general screening?
10%
What is the sensitivity of D-Dimer for proximal DVT?
97%
What is the sensitivity of duplex US scan for DVT?
97% sens, 94% sp for proximal clots. 73% for calf DVT.
What other potential Dx’s may you pick up with calf US to r/o DVT? (DVT DDx)
Baker’s cyst, hematoma, arterial aneurysm, abscess, lymphadenopathy, superficial thrombophlebitis.
What might be your next step if you have a negative duplex US in a pt in whom you have a high clinical suspicion of DVT?
Repeat US in 5-7 days to r/o extending calf clot
Treatment options for DVT
1) LMWH (dalteparin 200U/kg q24 or enoxaparin 1.5 mg/kg q24) and bridge to warfarin 5-10 mg/day titrating to INR (stop LMWH after 2d therapeutic INR)
2) Xarelto (achieve full anticoagulation within 1-3 hrs0
How long do pts with DVT need to remain on prophylaxis for?
At least 3 months of transient coagulopathy (e.g. leg cast, surgery).
At least 6 months if unprovoked.
Lifelong if ongoing coagulopathy (e.g. cancer)
When should you consider thrombolytic therapy for DVT?
Extensive iliofemoral thrombosis if there is concern for limb compromise.
What is the classic triad for PE
SOB, pleuritic CP, hemoptysis
Well’s criteria: how many pts # risk stratification group and likelihood of PE per group
Low risk: <2 pts, 3%
Intermediate: 2-6 pts, 28%
High: >6 pts, 78%
What are the PE Well’s Criteria?
Clinical signs of DVT: 3 pt Alt Dx less likely than PE: 3 pt HR >100: 1.5 Immobilization or Sx w/in 4 wks: 1.5 Prior DVT/PE: 1.5 Hemoptysis: 1 Malignancy (ongoing tx, palliative): 1
What is PERC and when can you use it?
PE R/O Criteria.
Apply to patients who have already been risk stratified as ‘low’ by Well’s.
Can be applied in pt populations with prevalence of disease <10-15%.
Does not apply to pts who are pregnant or post-partum.
If PERC is negative, no objective PE testing is required
What are the PERC criteria (8)?
1) Age <50
2) HR <100
3) O2 Sat >94% RA
4) No hx DVT or PE
5) No recent Sx
6) No hemoptysis
7) no estrogen use
8) no clinical signs DVT
DDx for PE (pleuritic CP)
Pericarditis, ACS, PNA
Signs of PE on EKG
Sinus tachycardia.
R ventricular strain (ST dep and inverted T waves in anterior and inferior leads).
S1Q3T3: deep S in lead I, Q wave and inverted T in lead 3
What are classic (but rarely present) signs of PE on CXR?
Hamptons hump: pleural based triangular density indicating infarction.
Westermark sign: focal oligemia indicating decreased pulmonary arterial flow.
Non-specific findings: atelectasis, parenchymal disease, pleural effusion
What is the utility of D-Dimer testing for PE?
In low to moderate risk probability pts, a negative D-dimer exludes PE with a 3 month thromboembolic rate of 1%
What percentage of PE arise from leg DVT?
90%
Describe the utility of D-Dimer in pregnant patients?
May still be negative in first trimester. ~up to 50% of pts in first trimester will have negative D-dimer and this can safely exclude VTE.
Approach to ?PE in pregnants pts
My teaching deviates from ABC’s: start with leg doppler, if +, then treat empirically. If negative but still high suspicion, just do the CT PE.
PE treatment?
LMHW+warfarin or DOAC (e.g. xarelto).
Hemodynamically unstable or cardiogenic shock: thrombolysis or clot extraction. IV tPA 100 mg IV over 2 hrs. Alt can give tPA 0.6 mg/kg IV stat bolus (typically 50 mg IV) if near death.
My addition: clot extraction or local thrombolysis
