Harrison's 262: Deep venous thrombosis & pulmonary thromboembolism

Question 1

VTE (venous thromboembolism) encompasses:

Answer 1

1) DVT

2) PE

Question 2

Along with MI & CVA, what is the third major cardiovascular cause of death?

Answer 2

venous thromboembolism!

Question 3

What is the most dangerous, acute risk of DVT?

Answer 3

Pulmonary embolus

Question 4

What are 2 chronic complications of VTE?

Answer 4

#Chronic thromboembolic pulmonary hypertension
#Postphlebitic syndrome

Question 5

What has Medicare stated re: VTE events after total hip or knee replacements?

Answer 5

They are unacceptable “never events” and hospitals cannot be reimbursed for expenses related to them.

Question 6

What is post-phlebitic syndrome?

Answer 6

Delayed complication of DVT that causes the valves in leg veins to become incompetent. Veins exude interstitial fluid, legs swell, sometimes ulcerate.

Worst part? We can’t fix it.

Question 7

What is chronic thromboembolic pulmonary hypertension?

Answer 7

Does what it says on the box: pulmonary hypertension left over after a PE. It is often disabling & causes breathlessness.

Question 8

So what’s so bad about DVTs?

Answer 8

Venous thrombi get dislodged & embolize to the lungs, where they hang out in the pulmonary arterial circulation like little punks. If there’s a patent foramen ovale or atrial-septal defect, they might go ANYWHERE in the arterial circulation, which becomes a real pain in the butt.

Question 9

How does a PE kill ya?

Answer 9

Progressive right heart failure!

Question 10

Wait, a PE gives you right heart failure?

Answer 10

Yes! Pulmonary vascular resistance goes up, RV tension rises & causes dilation. RV contraction keeps on going during LV diastole, squishing the poor little LV, which can’t fill up properly with blood. Cardiac output goes down, cardiac perfusion begins to suck, ischemia happens, and POOF circulatory collapse. Dead.

Question 11

True or false: PE pretty much looks like everything else.

Answer 11

True! PE is super hard to detect when it occurs concurrently with heart failure or pneumonia.

Question 12

What’s a good blood test to start with for VTE?

Answer 12

D-dimer! If it’s abnormally high, go straight to imaging.

Question 13

Physical findings in a DVT:

Answer 13

Mild DVT: mild palpation discomfort in calf
Massive DVT: HOLY CRAP YOUR LEG IS HUGE. Also painful palpation of femoral vein. They might not be able to walk because of pain.

Question 14

Differential diagnosis for DVT

Answer 14

# Ruptured Baker's cyst
# Cellulitis
# Post-phlebitic syndrome/venous insufficiency

Question 15

Differential for PE

Answer 15

# Pneumonia, asthma, or COPD
# CHF
# Pericarditis
# Pleurisy, costochondritis, musculoskeletal pain
# Rib fracture, pneumothorax
# ACS
# Anxiety (maybe you're freaking out 'cause you have a PE?)
# TOLD YOU PE LOOKS LIKE EVERYTHING ELSE!

Question 16

Non-imaging ways to test for DVT or PE

Answer 16

#D-dimer, which isn't very specific.
#Elevated troponins re: RV microinfarction. This is a pretty late in the game sign, though.
#ECG: "S1Q3T3 sign" S-wave in lead I, Q-wave in lead III, and inverted T-wave in lead III. Pretty specific, but not sensitive.

Question 17

Non-invasive imagine for PE/DVT

Answer 17

#Venous ultrasound
#Chest x-ray
#Chest CT
#Lung scan
#MRI

Question 18

Criteria for diagnosing acute DVT via ultrasound:

Answer 18

1) Lack of vein compressability (major criterion!)
2) Vein does not “wink” when compressed in cross section
3) Failure to appose walls of vein due to passive distention

Question 19

What does a thrombus look like on ultrasound?

Answer 19

Homogenous with low echogenicity

Question 20

What will the doppler flow look like on ultrasound re: DVT?

Answer 20

Normal response: calf compression augments Doppler flow signal & confirms vein patency proximal & distal to doppler
Abnormal response: flow is BLUNTED with calf compression

Question 21

Invasive imaging for DVT/PE

Answer 21

#Pulmonary angiography
#Contrast phlebography (but venous ultrasound has basically replaced this)

Question 22

What is meant by “primary vs. secondary” therapy for PE?

Answer 22

Primary: Clot dissolution with thrombolysis or removal by embolectomy
Secondary: Anticoagulation or placement of an IVC filter

Question 23

Primary therapy should be reserved for…

Answer 23

…high risk patients!

Question 24

Who are these “high risk” PE folks?

Answer 24

They are hemodynamically unstable, have RV dysfunction or enlargement, or high troponins from RV infarct!

Question 25

Does anticoagulation dissolve the clot?

Answer 25

Nope. It just keeps the clot from growing while it resorbs naturally.

Question 26

What drugs might we use to do this anticoagulation thing?

Answer 26

Heparin (fractionated or unfractionated), which we would then overlap with warfarin until therapeutic INR (which is between 2 & 3) is reached.

Question 27

One more time, the target INR for warfarin in DVT? Hmmmm?

Answer 27

2-3!

Question 28

True or false: Acute DVT patients MUST be admitted to the hospital.

Answer 28

False! They can often be managed as outpatients if they can do the whole unfractionated heparin shot thing.