VTE

Question 1

What are the components of the ‘thrombosis’ mnemonic for RF for VTE?

Answer 1

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)

Question 2

Well’s DVT score: # pts per category and overall risk of DVT per category

Answer 2

Low risk: 0 pts, 5% likelihood DVT
Moderate risk: 1-2 pts, 33%
High risk: 3+ pts, 85% risk

Question 3

Where in the venous system are symptomatic DVTs typically present?

Answer 3

At or proximal to popliteal vessels in >80% of cases. A calf DVT will extend proximally in only 20% of cases.

Question 4

What are DVT well’s criteria (9)?

Answer 4

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

Question 5

Screening/diagnostic tools for DVT (5)

Answer 5

D-dimer, doppler US (duplex), contrast venography, CTV (CT venography), MR venography (MRV)

Question 6

What is a ‘d-dimer’

Answer 6

Fragments of degradation products of fibrin. Elevated levels indicate activation of clotting mechanisms.
Only useful if test is negative

Question 7

Which pts is D-Dimer testing useful for in r/o DVT?

Answer 7

Low-moderate risk (over 99% NPV)

Question 8

What % of pts over 85 will have a positive D-dimer with general screening?

Answer 8

10%

Question 9

What is the sensitivity of D-Dimer for proximal DVT?

Answer 9

97%

Question 10

What is the sensitivity of duplex US scan for DVT?

Answer 10

97% sens, 94% sp for proximal clots. 73% for calf DVT.

Question 11

What other potential Dx’s may you pick up with calf US to r/o DVT? (DVT DDx)

Answer 11

Baker’s cyst, hematoma, arterial aneurysm, abscess, lymphadenopathy, superficial thrombophlebitis.

Question 12

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?

Answer 12

Repeat US in 5-7 days to r/o extending calf clot

Question 13

Treatment options for DVT

Answer 13

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

Question 14

How long do pts with DVT need to remain on prophylaxis for?

Answer 14

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)

Question 15

When should you consider thrombolytic therapy for DVT?

Answer 15

Extensive iliofemoral thrombosis if there is concern for limb compromise.

Question 16

What is the classic triad for PE

Answer 16

SOB, pleuritic CP, hemoptysis

Question 17

Well’s criteria: how many pts # risk stratification group and likelihood of PE per group

Answer 17

Low risk: <2 pts, 3%
Intermediate: 2-6 pts, 28%
High: >6 pts, 78%

Question 18

What are the PE Well’s Criteria?

Answer 18

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

Question 19

What is PERC and when can you use it?

Answer 19

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

Question 20

What are the PERC criteria (8)?

Answer 20

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

Question 21

DDx for PE (pleuritic CP)

Answer 21

Pericarditis, ACS, PNA

Question 22

Signs of PE on EKG

Answer 22

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

Question 23

What are classic (but rarely present) signs of PE on CXR?

Answer 23

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

Question 24

What is the utility of D-Dimer testing for PE?

Answer 24

In low to moderate risk probability pts, a negative D-dimer exludes PE with a 3 month thromboembolic rate of 1%

Question 25

What percentage of PE arise from leg DVT?

Answer 25

90%

Question 26

Describe the utility of D-Dimer in pregnant patients?

Answer 26

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.

Question 27

Approach to ?PE in pregnants pts

Answer 27

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.

Question 28

PE treatment?

Answer 28

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