Chapter 147 - Acute LE DVT - introduction

Question 1

Symptoms of acute DVT

Answer 1

1) dull ache 2) pain 3) tenderness 4) swelling 5) erythema 6) cyanosis 7) fever

Question 2

Phlegmasia cerulea dolens symptoms

Answer 2

1) edema 2) cyanosis 3) pain

Question 3

Cause of venous gangrene

Answer 3

1) cancer 2) HITT 3) warfarin-mediated protein C depletion

Question 4

Two factors that aid in diagnosis of DVT

Answer 4

1) past history of DVT 2) malignant disease

Question 5

What is D-dimer

Answer 5

1) Product of fibrin proteolysis by plasmin 2) indicates fibrinolysis of complexed fibrin

Question 6

Other causes of elevated D-dimer

Answer 6

1) trauma 2) pregnancy 3) surgery 4) cancer 5) thrombotic disorders

Question 7

Non-compressibility of vein sensitivity and specificity on US

Answer 7

97% 94%

Question 8

Limitation of compression ultrasound

Answer 8

1) poor accuracy in calf veins 2) fresh thrombi 3) small segmental thrombi 4) obese patients or significant edema

Question 9

Key limitation points in duplex US in DVT

Answer 9

1) low risk patients may get false positive 2) duplex US cannot reliably rule out distal DVT

Question 10

Risk of PE from calf muscle vein thromboses vs calf vein thromboses

Answer 10

CMVT 50% risk CV DVT 10-15% risk

Question 11

Two different Techniques of contrast venography

Answer 11

1) Rabinov-Paulin technique = spot film 2) Long-leg technique = cine film Long leg has less interobserver disagreement and easier to interpret

Question 12

CTV and MRV in DVT diagnosis

Answer 12

Both have variable results but overall 90’s for sen and spe MRI better for proximal DVT not as good below knee

Question 13

What is 18F-FDG

Answer 13

18F-labelled fluorodeoxyglucose glucose analogue absorbed by tissue and cells with rapid metabolism

Question 14

What type of cells would 18F-FDG label

Answer 14

1) tumor cells 2) endothelial cells 3) macrophages 4) lymphocytes

Question 15

use of 18F-FDG PET/CT in DVT

Answer 15

sen 87.5 spe 100 help differentiate from DVT and tumor DVT

Question 16

fold increase in DVT with various diseases: Heterozygous antithrombin deficiency Protein C deficiency Protein S deficiency Life risk heterozygous factor V Leiden Others

Answer 16

AT 5-50x protein C 3x Protein S 10x Factor V Leiden 10% others 2x or less

Question 17

risk of DVT in the absence of prophylaxis after surgery of various types

Answer 17

hip # 50% burn 33% Ortho 36% uro 33% gen 25% neuro 23% abd 19% PAD 15%

Question 18

Wells score for DVT

Answer 18

1) active cancer 2) paralysis/paresis/immobolization 3) major surgery in 12 weeks needing general/regional anes causing (3d bed rest) 4) tenderness along deep venous system 5) entire leg swollen 6) calf > 3cm larger than contralateral side 7) pitting edema ipsilateral 8) collateral superficial veins nonvaricose 9) previous DVT - 2 points if other diagnosis possible

Question 19

Where do you measure calf circumference for DVT

Answer 19

10 cm below tibial tuberosity

Question 20

Well score stratified risk for high intermediate and low risk

Answer 20

High = 47% intermediate 12% low 4%

Question 21

Negative D dimer in low or intermediate wells score patients treatment

Answer 21

No further workup risk < 0.6% in 3 months

Question 22

Negative D dimer in high risk patient PE risk

Answer 22

15%

Question 23

Problem in using wells score in hospitalized patients

Answer 23

underestimates risk of DVT/PE

Question 24

Algorithm for clinically likely DVT

Answer 24

FIGURE 147.7

Question 25

Algorithm for clinically unlikely DVT

Answer 25

FIGURE 147.8

Question 26

Rate of recurrent DVT in first year

Answer 26

11-18%

Question 27

Challenges in detecting recurrent DVT

Answer 27

1) All are considered high risk 2) Ultrasound findings hard to interpret 3) post-thrombotic changes similar to acute DVT

Question 28

How to determine age of thrombus in DVT

Answer 28

1) radiolabelled recombinant TPA for 30 day + old thrombus 2) MRI for 6 month + old thrombus

Question 29

Landmark paper that anticoagulation is used to treat DVT

Answer 29

Barritt and Jordan 1961

Question 30

Contraindication to outpatient treatment of acute DVT

Answer 30

1) high bleed risk 2) severe symptomatic venous obstruction 3) thrombocytopenia 4) poor hepatic function 5) unstable renal function 6) non-compliance 7) poor social support

Question 31

Non-anticoagulation treatments of acute DVT

Answer 31

1) compression therapy 2) leg elevation 3) early ambulation

Question 32

Goals of DVT treatment x2

Answer 32

1) immediate reduction of M&M in short term 2) reduction of late post-thrombotic morbidity

Question 33

Current treatment of calf/distal DVT

Answer 33

1) controversial surveillance vs anticoag 3 month 2) factors to trigger anticoag: 1) elevated d-dimer 2) thrombotic burden 3) history of VTE 4) thrombophilic states

Question 34

Femoral vein dvt vs popliteal vein dvt symptoms

Answer 34

femoral is mild because of popliteal drain via profunda to CFV popliteal DVT is morbid

Question 35

Anticoagulation alone for iliofemoral DVT long term problems

Answer 35

1) intraluminal scar with type 1 and 3 collagen 2) 95% valvular dysfunction 3) 30% venous claudication/ulceration 4) recurrence due to May Thurner

Question 36

Unfractionated heparin Mechanism bleeding risk other risk

Answer 36

Factor II and X inhibition via antithrombin activation 2% major bleed HIT 0.5-2%

Question 37

LMWH names Mechanism bleeding risk other risk

Answer 37

Enoxaparin, dalteparin, tinzaparin Selective factor X inhibition via antithrombin activation 2% major bleed HIT \< 1%

Question 38

Fondaparinux Mechanism bleeding risk other risk

Answer 38

Selective factor X inhibition via antithrombin activation 1.2% major bleed Thrombocytopenia 0.5%

Question 39

Parenteral DTI names Mechanism bleeding risk other risk

Answer 39

Argatroban, bivalirudin direct factor II inhibitor 1.3% major bleed (A), 3.5% major bleed (B) hypotension, tachycardia

Question 40

Warfarin Mechanism bleeding risk other risk

Answer 40

Vitamin K dependent factor inhibition (2, 7, 9, 10) 1.2-1.9% major bleed food drug interactions

Question 41

DOAC names mechanism bleeding risk other risk

Answer 41

direct oral inhibitor of factor Xa apixaban, rivaroxaban, edoxaban Major bleed 0.6-1.4% Increased exposure in renal failure eGFR \< 30 apixaban has least renal clearance and does not need dose adjustment increased exposure and liver toxic for rivaroxaban and edoxaban only

Question 42

Therapeutic range of heparin

Answer 42

1.5-2.5x aPTT control value plasma heparin assay to get level 0.3-0.7 IU/ml

Question 43

Discovery of LMWH year

Answer 43

1976

Question 44

Half life of LMWH

Answer 44

3-5 hours

Question 45

ACCP guideline for anticoagulation in cancer

Answer 45

first 3 months with LMWH

Question 46

Treatment of HITT

Answer 46

Argatroban or bivalirudin

Question 47

Why do antibiotics affect warfarin dosing

Answer 47

Destruction of gut flora that produced vitamin K

Question 48

EINSTEIN trial key points

Answer 48

1) rivaroxaban reduces recurrent VTE 2.1 vs 3%

Question 49

Dabigatran mechanism bleeding risk other risk

Answer 49

DOAC but factor IIa inhibitor 1.6% major bleed renal clearance

Question 50

Antidote for dabigatran and dose

Answer 50

Idarucizumab 5g IV

Question 51

Use of graduated compression stockings in acute DVT

Answer 51

controversial no clear benefit in reducing post-thrombotic syndrome

Question 52

PROLONG trial key points

Answer 52

1) abnormal d-dimer randomized to anticoag or stop anticoag 2) increased recurrence in patients that did not receive ongoing treatment

Question 53

WARFASA and ASPIRE trials key points

Answer 53

32% reduction in VTE and 34% reduction in major vascular event without significant bleeding when ASA is used in addition

Question 54

AMPLIFY-EXT trial key points

Answer 54

Apixaban vs placebo in preventing recurrent DVT after 6-12 months of therapeutic anticoagulation 1) 2.5 or 5 mg BID had lower VTE/death than placebo 1.7 vs 8.8% 2) bleeding higher with treatment 2.3 vs 3.0 vs 4.2% 3) NNT = 14 to prevent 1 VTE 4) NNH = 200 to cause bleed Limitation 15% over age 75 few patients with CKD \> 3