VTE Part 1 Flashcards
General Background
Hemostasis vs Thrombosis
Arteries vs Veins
• Hemostasis
– Physiologic
– Process causing bleeding tostop, meaning to keep blood within a damaged blood vessel
• Thrombosis
– Pathologic
– Formation of a blood clot within a blood vessel,
obstructing blood flow through the circulatory system
Arteries vs Veins • Blood flow in the circulatory system • Arteries – High flow / pressure – Carry oxygenated blood – Generally smaller lumen with thicker (more muscular) walls
• Veins
– Low flow / pressure
– Carry deoxygenated blood
- Generally larger lumen with thinner walls
White vs Red Clot:
Oversimplified
clot location flow in vessel composition of clot culprit tx of choice
see slide 7
WHITE Clot “Atherosclerotic” RED Clot “Thrombus” or “Thromboembolic”
Clot location: Arterial Venous
Flow in vessel: High flow / pressure (atherosclerosis)
Low flow / pressure (stasis)
Composition of Clot” Platelets
Red blood cells trapped with fibrin
Culprit” Platelets
Clotting Factors / Fibrin
Treatment of Choice: Antiplatelet Anticoagulant
Factors Contributing to & Clinical Conditions
of Thrombosis
virchow\s triad
hypercoagulable state
endothelial injury
circulatory stasis
Abnormality of the blood (hypercoagulable state) -causing “overactive” clotting factors (hypercoagulable states) -increase estrogen -cancer
Abnormality of blood vessel (endothelial injury_
- disruption of atherosclerotic plaque (MI, cerebrovascular stroke)
- injury (trauma – fractures, surgery)
- change in “tissue” (heart valve replacement)
Abnormality of blood flow (“sluggish” flow) (circulatory stasis)
- Venous blood flow is a relatively low pressure (versus arterial),stasis may occur (prevent clearing of clotting factors).
- Risk includes: immobilization (bed rest, paralysis → VTE), disease states (CHF, AF → embolic stroke)
What is Venous Thromboembolism (VTE)?
VTE occurs in 1-2 per 1000 person years in general population
• Annual incidence of symptomatic DVT ~ 145/100,000
• Annual incidence PE ~ 66/100,000
• Incidence increases with age
• Mortality from PE occurs early
VTE = general term encompassing a blood clot that forms in a vein and may/may not embolize; Captures both DVT and PE
Deep Vein Thrombosis (DVT):
• Thrombosis occurring in the deep veins
• Most commonly in leg, may occur in other
veins (arms, mesenteric, cerebral)
Pulmonary Embolism (PE):
• Blockage of lung artery by a clot that has traveled from elsewhere in bloodstream
• Most commonly from deep veins of leg or pelvis
see slide 10-11 for clotting cascade
k
Antithrombotic Agents=
antiplatelet, anticoagulant, fibrinolytic
oral antiplatelets
injectable antiplatelets
antiplatelets and coagulants
Stabilizes Clot
Prevents Clot Growth
Prevents New Clot Formation
oral antiplatelets: Acetylsalicylic Acid (ASA) Ticlopidine Clopidogrel Dipyridamole Prasugrel Ticagrelor
injectable antiplatelets: Abciximab Eptifibatide Tirofiban (GP IIb/IIIa Inhibitors)
oral anti-coagulants: Warfarin Dabigatran Rivaroxaban Apixaban Edoxaban
injectable anti-coagulants: LMWH Fondaparinux UFH Lepirudin Bivalirudin
Fibrinolytics -Breaks down
the clot
Antifibrinolytic - Prevents clot
break down
fibrinolytics Streptokinase Alteplase Tenecteplase Reteplase
anti-fibrinolytic
Tranexamic acid
Aminocaproic acid
Leg Deep Venous Thrombosis:
Proximal vs Distal DVT
Proximal DVT
– Anything above the knee / located in the popliteal vein or above
– Larger veins, larger clots
– 70-80% of DVTs
– Larger clots, increased likelihood of embolization to the lungs
• Distal DVT – Anything below the knee – Smaller veins, smaller clots – 20-30% of DVTs – Likelihood of clot growth/extension into the proximal system (~15% will extend)
Misnomer … the Superficial femoral vein is NOT superficial ….
Signs & Symptoms of DVT
• Pain and tenderness in the affected area
• Swelling (distal to clot)
• Discoloration
• Joint pain and soreness
• Warmth in the affected area
• Palpable Cord
• Superficial venous dilation
• Presentation is relatively non-specific, as signs/symptoms are not unique to DVT
• Objective testing is necessary to confirm / exclude the
diagnosis of DVT
Signs & Symptoms
of PE
• Shortness of breath, “breathlessness”
• Hypoxemia
• Tachycardia
• Sudden, unexplained cough
• Pleuritic Chest pain (=worsens with
breathing, coughing, sneezing) & Hemoptysis may occur
• Dyspnea, Fatigue
• Increase in pulmonary vascular resistance → right ventricular strain /enlargement / failure (Pulmonary Pattern on 12-lead ECG)
– Pulmonary embolism with cor pulmonale
• Syncope, confusion, coma/shock, hemodynamic instability
Clinical significance depends on:
- Size of embolus/emboli
- Patient’s cardiorespiratory reserve
Severity of PE
3 classes, which need hospitalization?
Massive: Unstable, in shock < 5% PEs, > 15% death
Sub-massive: No hypotension, beginning of right ventricular (RV) failure (large RV) or signs of RV strain,
positive biomarkers (troponin, BNP)
~ 15%, 3 - 15% death
Non-massive* Stable ~ 80%, < 1% death
*5-50% with PE are treated at home (as outpatients) vs admitted to hospital
• Non-massive patients are not required to be
admitted to hospital (=may be managed as an
outpatient - >40% in Edmonton Zone)
• Non-massive and sub-massive were studied in
clinical trials of DOACs vs LMWH/warfarin for PE
• Massive are all admitted
Clinical Consequences of VTE
VTE = DVT + PE
DVT Clot extension/embolization → PE Recurrence (20% will be PE) Post-thrombotic syndrome (legs/arms) Pain / Discomfort in limb
PE DEATH (3rd most common CV cause)* Prior to Presentation (within hours) Risk of early death (1st month) Recurrence (60% will be PE) Chronic thromboembolic pulmonary hypertension (CTEPH) Right ventricular failure *after MI and stroke
Death due to PE occurs early – implying:
• Early detection / treatment is important
• Identification and prophylaxis for those at risk of DVT/PE are key
• Prevention is the most effective approach
Goals of VTE Treatment
• Prevent death from PE • Reduce the symptoms of the clot • Prevent long-term complications – DVT – PE • Minimize adverse effects of medications • Longer Term: Prevent recurrence of VTE
Which of the following is correct?
1. Patients having a proximal DVT should be
counseled about their risk of also having an
embolic stroke (=clot traveling to the brain)
2. Clots occurring with VTE are red clots therefore
are best treated with antiplatelet drugs
3. Anticoagulants will help break down the clot
4. Pulmonary embolism is most concerning given
the risk of sudden death & proximal leg clots are
more likely to embolize compared to distal leg
clots
Pulmonary embolism is most concerning given
the risk of sudden death & proximal leg clots are
more likely to embolize compared to distal leg
clots
Diagnosis – Role of the Pharmacist
• Access to reports (NetCare) – read report / summary
• Confirmation (report) of the diagnosis
• Severity / Extensiveness of the clot - impacts care /
complications
