1. Venous Thromboembolism: Risk Factors, Assessment, & Prevention
Stacey Graven, ACNP
Vascular Surgery, Springfield Clinic
Springfield, Illinois

2. VTE
In September 2008, Surgeon General issued a “Call to Action to Prevent Deep Venous Thrombosis and Pulmonary Embolism”
Recognized as significant public health problem
Limited awareness about DVT -- < 1 in 10 Americans are familiar with DVT

3. Incidence of VTE VTE defined as patients with DVT, PE or both
In US, 300,00-600,000 cases per year
Occur more often in elderly population
Over 80 year old population, 1 per 100
Am J Prev Med 2010;38(4S)S495-S501

4. Incidence of VTE Higher incidence in black and white populations
Higher incidence in men
Except women during reproductive years
Am J Prev Med 2010;38(4S)S495-S501

5. Morbidity and Mortality of VTE
VTE is often fatal
Leading cause of preventable hospital death and maternity deaths in US
Over 100,00 people die every year from VTE
10%-30% of VTE patients die within 30 days of diagnosis
About ¼ of deaths are sudden
Circulation. 2009; 119: e480-e482, Am J Prev Med 2010;38(4S)S495-S501

6. Morbidity and Mortality of VTE
Despite standard anticoagulation therapy--
1/3 suffer recurrence within 10 years.
Highest risk of recurrence within 1st year
About ½ of DVT patients develop chronic health-related problems:
Post-thrombotic syndrome
Chronic venous insufficiency with venous ulcerations
Pulmonary hypertension
Am J Prev Med 2010;38(4S)S495-S501

7. Risk Factors for VTE-Acquired
Chronic disease
Advanced age
Obesity
Antiphospholipid antibodies
Malignancy
Travel
Prior history of VTE
Smoking
Pregnancy, hormone therapy, oral contraceptives

8. Risk Factor- Hospitalization
> 50% of cases linked to hospitalization
Often occur within 3 months of discharge
Multiple risk factors
Surgery
Trauma
Central line catheters
Immobilization
Am J Prev Med 2010;38(4S)S495-S501

9. Genetic Risk Factors Genetic disorders < 1%-5% population
increase VTE risk 3-10 fold in heterozygous state
Factor V Leiden
Protein S Deficiency
Protein C Deficiency
Antithrombin Deficiency
Sickle Cell Trait
Am J Prev Med 2010;38(4S)S495-S501

10. Virchow’s Triad Three factors contributing to thrombus formation
Hypercoagulability—hormone therapy, genetic disorder
Interrupted blood flow/stasis--immobility, varicose veins
Endothelial dysfunction/injury– shear stress, catheters/devices

11. Clotting Cascade
Thrombin inhibitors (Pradaxa), Factor Xa Inhibitors (Eliquis), LMWH…..block clotting pathways

12. Familiar Faces of VTE

13. Deep Venous Thrombosis
Thrombus in deep vein
Most common in legs, arms
Deep veins empty into
vena cava

14. Deep & Superficial Veins
Superficial veins communicate with deep veins via perforator veins
SVT (superficial thrombophlebitis) can develop into DVT

15. Signs & Symptoms DVT Lower leg swelling, tightness of skin
Calf tenderness
Warmth
Redness
Can also occur in upper extremity- venous catheters

16. Diagnosing DVT Ultrasound- sensitivity 98% Inexpensive
Difficult in obese patients
Limitations with duplicate vein systems
Normal vein compression Unable to compress in DVT

17. Diagnosing DVT
Ultrasound—color flow images
Normal flow Thrombus

18. Diagnosing DVT
D-dimer- reflects presence of degradation products of fibrin and fibrinogen
Sensitivity 97% for DVT
Nonspecific – 35%
Elevated D-dimer
Infection
Post-op states
Malignancy
Recent trauma
Better used in conjunction with duplex
Rutherford’s Vascular Surgery, 7th edition, 2010

19. Diagnosing DVT MRV and CTV Noninvasive More expensive than duplex
Better images in pelvic region in obese patients
If duplex not diagnostic

20. MRV
Left common iliac vein DVT Right common femoral vein DVT

21. CTV
Right common femoral DVT

22. Calf DVT versus Proximal DVT
Location of DVT --
Proximal DVT - higher risk of PE and long- term complications

23. Calf versus proximal DVT
Calf vein DVT
20-30% of DVTs
Includes anterior tibial, peroneal, and posterior tibial veins
Recanalize faster
50% reduction in thrombus by 1 month and complete in one year
Proximal vein DVT
Includes femoral, iliac, and inferior vena cava
Higher risk of PE, phlegmasia, and post thrombotic syndrome

24. Post Thrombotic Syndrome (PTS)
Common complication of proximal DVT - venous hypertension
Valves are dysfunctional due to thrombus
Blood moves in both
directions causing
hypertension in venous
system

25. Post Thrombotic Syndrome
Post thrombotic syndrome – most important late effects of proximal DVT
Chronic pain
Swelling
Ulcerations
Hyperpigmentation- leaking of
blood products

26. Complication of Proximal DVT
Post Thrombotic Syndrome

27. Complication of Proximal DVT
Phlegmasia --limb threatening
Severe DVT with complete or near complete occlusion of proximal vein
Venous congestion causes arterial compression
Leg very painful, cyanotic, no pedal pulse
Gangrene

28. Pulmonary Embolism
Embolism travels to pulmonary arterial bed and occludes blood flow to lungs.
Hemodynamically significant –
>30-50% arterial bed occluded

29. Pathophysiology of PE

30. Pulmonary Embolism In most cases, PE is associated with DVT
50% of PE related to proximal DVT
Occurs 3-7
days after
onset of DVT

31. Signs & Symptoms PE Sudden shortness of breath -- 80% confirmed PE
Chest pain (pleuritic, substernal) -- 52%
Hemoptysis -- 11%
Syncope -- 19%
Tachycardia -– 26%
Fever ( > 38.5 ) -- 7%
Cyanosis – 11%
European Heart Journal (2008) 29,

32. Pathophysiology of PE
Multiple emboli increase pulmonary vascular resistance– RV strain, increased afterload

33. Pathophysiology of PE

34. Markers of PE Elevated right heart pressures Abnormal echo—RV strain
Elevated BNP and troponin
EKG changes – RV hypertrophy/strain, leads V1-V4
Hypotension, hypoxia  shock

35. RV Strain on Echo
Right ventricular dilatation and hypokinesis

36. Pulmonary Embolism Varying degrees of PE depending on thrombus burden
Massive PE 5-10% --- hypotension, pulselessness
Submassive PE 20-25% --- myocardial infarction w/o hypotension
Low risk PE 70% --- no significant hemodynamic changes
Treatment is dictated by severity
Circulation(2011) 123,

37. Diagnosing PE Often when presenting with chest pain/SOB:
EKG – rule out myocardial infarction
Chest x-ray – rule out pneumonia, atelectasis, pulmonary edema
Arterial blood gas – 20% of PE have P02 > 80%
Labs – D-dimer, cardiac markers

38. Diagnosing PE CT chest Most common diagnostic tool used to confirm PE
Improving visualization of thrombus

39. Diagnosing PE Ventilation Perfusion Scan (V/Q scan)
Second line of imaging
Used when CT contrast allergy
Use radioisotope
Compares ventilation (air flow into/out of lungs) and perfusion (blood flow into/out of lungs)
V/Q mismatch--seen in other conditions, i.e. emphysema, pneumonia
Radiology reads as “probability” of PE

40. Diagnosing PE
Pulmonary Angiogram – gold standard

41. Treatment VTE
Anticoagulation—UFH, LMWH, Factor Xa Inhibitor, Direct thrombin inhibitor, Vitamin K antagonist
Thrombolysis– indicated in proximal DVT/PE. Lowers incidence PTS
Embolectomy– mechanical removal of thrombus, catheter vs surgical
IVC Filter– temporary/permanent
Compression – all DVT patients, prevent PTS

42. Prevention is the Key Growing health problem—often preventable
Reduce mortality and long-term effects

43. Prevention/Screening
VTE is the #1 preventable causes of death in hospital patient
2/3 of VTE are result of hospitalization
Inpatients with VTE -- < 30% received prophylaxis
Every hospital patient -- must risk-assessed for VTE

44. Risk assessment of VTE Prophylaxis treatment based on:
specific disease process and patient’s risk
More risk factors  greater risk VTE
> 40 years of age
Smoking
Overweight
Personal/Family history of blood clots
Birth control pills or HRT
Malignancy
Varicose Veins
Surgery, especially hip, knee, or abdominal surgery, and
Decreased mobility due to long illness or surgery

45. Prophylaxis in Hospital
Mechanical
Pneumatic compression boots in bed
Pharmacological
LMWH – enoxaparin (Lovenox) 40 mg SQ daily or
dalteparin (Fragmin) 5000 u SQ daily
Fondaparinux (Arixtra) 2.5 mg SQ daily used after orthopedic surgery
UFH (Heparin) 5000 u SQ every 8 hours
Warfarin

46. Long-term Prevention Compression stockings daily
Avoid sitting for long periods of time – travel
Avoid dehydration--alcohol

47. Venous Thromboembolism

48. Thank you Questions??