Transcript Venous Thromboembolism: Risk Factors, Assessment, & Prevention

Stacey Graven, ACNP
Vascular Surgery, Springfield Clinic
Springfield, Illinois
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
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
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
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
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
Risk Factors for VTE-Acquired
 Chronic disease
 Advanced age
 Obesity
 Antiphospholipid antibodies
 Malignancy
 Travel
 Prior history of VTE
 Smoking
 Pregnancy, hormone therapy, oral contraceptives
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
Genetic Risk Factors
 Genetic disorders
 < 1%-5% population
 increase VTE risk 3-10 fold in heterozygous state
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Factor V Leiden
Protein S Deficiency
Protein C Deficiency
Antithrombin Deficiency
Sickle Cell Trait
Am J Prev Med 2010;38(4S)S495-S501
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
Clotting Cascade
 Thrombin inhibitors (Pradaxa), Factor Xa Inhibitors (Eliquis), LMWH…..block
clotting pathways
Familiar Faces of VTE
Deep Venous Thrombosis
 Thrombus in deep vein
 Most common in legs, arms
 Deep veins empty into
vena cava
Deep & Superficial Veins
 Superficial veins communicate with deep veins via
perforator veins
 SVT (superficial thrombophlebitis) can develop into
DVT
Signs & Symptoms DVT
 Lower leg swelling, tightness of skin
 Calf tenderness
 Warmth
 Redness
 Can also occur in upper extremity- venous catheters
Diagnosing DVT
 Ultrasound- sensitivity 98%
 Inexpensive
 Difficult in obese patients
 Limitations with duplicate vein systems
Normal vein compression
Unable to compress in DVT
Diagnosing DVT
 Ultrasound—color flow images
Normal flow
Thrombus
Diagnosing DVT
 D-dimer- reflects presence of degradation products of fibrin and
fibrinogen
 Sensitivity 97% for DVT
 Nonspecific – 35%
 Elevated D-dimer
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Infection
Post-op states
Malignancy
Recent trauma
 Better used in conjunction with duplex
Rutherford’s Vascular Surgery, 7th edition, 2010
Diagnosing DVT
 MRV and CTV
 Noninvasive
 More expensive than duplex
 Better images in pelvic region in obese patients
 If duplex not diagnostic
MRV
Left common iliac vein DVT
Right common femoral vein DVT
CTV
 Right common femoral DVT
Calf DVT versus Proximal DVT
 Location of DVT - Proximal DVT - higher risk of PE and long- term
complications
Calf versus proximal DVT
 Calf vein DVT
 20-30% of DVTs
 Includes anterior tibial, peroneal, and posterior tibial
veins
 Recanalize faster
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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
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
Post Thrombotic Syndrome
 Post thrombotic syndrome – most important late
effects of proximal DVT
 Chronic pain
 Swelling
 Ulcerations
 Hyperpigmentation- leaking of
blood products
Complication of Proximal DVT
 Post Thrombotic Syndrome
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
Pulmonary Embolism
 Embolism travels to pulmonary arterial bed and
occludes blood flow to lungs.
 Hemodynamically significant –
 >30-50% arterial bed occluded
Pathophysiology of PE
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
Signs & Symptoms PE
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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, 2276-2315
Pathophysiology of PE
 Multiple emboli increase pulmonary vascular resistance– RV strain,
increased afterload
Pathophysiology of PE
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
RV Strain on Echo
 Right ventricular dilatation and hypokinesis
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, 1788- 1830
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
Diagnosing PE
 CT chest
 Most common diagnostic tool used to confirm PE
 Improving visualization of thrombus
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
Diagnosing PE
 Pulmonary Angiogram – gold standard
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
Prevention is the Key
 Growing health problem—often preventable
 Reduce mortality and long-term effects
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
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
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
Long-term Prevention
 Compression stockings daily
 Avoid sitting for long periods of time – travel
 Avoid dehydration--alcohol
Venous Thromboembolism
 www.preventdvt.org
 www.stoptheclot.org
 www.venousforum.org
Thank you
Questions??