Working Problem 12-Thromboembolism Flashcards
When do you perform an D dimer?
•It can be used to rule out(high sensitivity low specificity )a disease when the pre-test probability of venous thromboembolism is low
It can also be used to assess venom induced consumptive coagulopathy and DIC
How do you assess pretest probability?
Assessed using Well score criteria for PE(
What are the non- pathological conditions associated with elevated D dimers
Age smoking functional impairment post operatively Pregnancy race(african-american)
What are the pathological conditions associated with elevated D dimers?
Acute coronary syndrome Atrial fibrillation Arterial or venous thromboembolism DIC or VICC Infection Malignancy Sickle cell anemia Trauma Acute upper GI bleed Stroke
What situation can result in false negative D dimer assay?
If you don’t perform the pre test probability correctly you will get negative D dimer(false negative)
There is a small clot load(small calf only DVT)
The thrombus has matured over time
The patient has defective fibrinolysis(which can contribute to thrombus formation in the first place(you need fibrinolysis to have fibrin degradation prod
What is pulmonary embolism?
Some or all of the thrombus get detached from the veins and move through the right heart and ends up lodging into the pulmonary arteries.
It causes SOB of breath(↓Q and Normal V→V/Q mismatch)
PE may cause SOB, Bloody sputum, chest pain, faintness and heart failure
Massive PE→death
What are the symptoms of PE?
What are the signs of PE?
Symptoms Dyspnea (73%) Pleuritic chest pain (44%) Non pleuritic chest pain (19%) Cough Wheezing
Signs Tachypnea (>20/min) (54%) Tachycardia(>100/min) ↑JVP Lung crackles Signs of DVT (50%)
What are the signs and symptoms of DVT
Swelling Tenderness Pitting edema Engorgement of superficial veins Post phlebitic syndrome
How do you prevent DVT?
Adequate hydration Early ambulation Mechanical o Graduated compression stockings o Intermittent Pneumatic compression o Electrical calf stimulation Pharmacological o Heparins including unfractionated heparin and low molecular weight heparins depending on risk o Direct oral anticoagulants: rivaroxaban,Apixaban,Dabigatran o Warfarin in some settings
How long should be treatment given?
For the time period of increased risk during and after • Hip and knee surgery • Cancer • Immobility • Previous VTE • Pregnancy
What is the aim of anticoagulation?
o Stabilisation of thrombus
o Prevention of propagation
o Prevention of PE
o It is usually not to dissolve the clot(unless very big)
How do you manage venous thromboembolism?
1) anticoagulation
2) Thrombolysis(only performed when patient is hypotensive or in cardiogenic shock)
3) mechanical(eg:IVC filter)
4) Surgical (eg:removal of embolus)
How long do you anticoagulate some for?
If provoked... Calf DVT • observe only(CUS at 10-14 days) • 10-14 days anticoagulation • 3 months anticoagulation
– Thigh/pelvis DVT
• 3-6 months anticoagulation
– PE
• 6-12 months anticoagulation
If unprovoked... – Calf DVT • observe only(CUS at 10-14 days) • 10-14 days anticoagulation • 3 months anticoagulation
– Thigh/pelvis DVT
• 6-12 months anticoagulation
– PE
• 12 months anticoagulation
What drug do you give when the patient is having heparin induced thrombocytopenia and thrombosis
o Fondaparinux(anti-10a)(injection)
• Oral anticoagulants – Warfarin (inhibition of Vit K) – Direct oral anticoagulants(DOACs) • Rivaroxaban • Dabigatran • Apixaban
All the novel drugs are as effective as warfarin with bans inhibiting factor 10 and dabigatran inhibiting thrombin
No drug interaction
Monitoring not required
What imaging are done for DVT?
Compression Ultrasonography(Most commonly used for DVT,operator dependent)
Contrast venography(gold standard reserved for those with clinical findings highly suggestive of DVT but doesn’t show in CUS)
What imaging is used for PE?
CT pulmonary angiography(diagnostic method of choice,fairly readily available,is easy and fast to perform and has good sensitivity(85%) and specificity(95%)
Large radiation burden and contrast required(not suitable for people with renal problems)
V/Q scan(used for renal patients and those allergic to contrast but has lower sensitivity and specificity as compared to CTPA)
Chest x ray(used only to rule out other causes as not reliable)BUT IT IS THE FIRST TEST TO BE ORDERED
look out for westermark’s sign(peripheral oligaemia) and Hampton’s hump which is a reliable sign(reliable sign of pulmonary infarction)
What are other test that are done for pulmonary embolism
1) ECG
a) It is to differentiate pulmonary embolism from myocardial infarction which can present in the same way(chest discomfort ,dyspnea ,raised JVP and hypotension)
b) ECG in pulmonary embolism relatively normal but might show signs of heart strain(Cor pulmonale, right axis deviation, right bundle branch block)
2) Troponin
a) Cardiac troponin levels may be elevated in patients with massive acute pulmonary embolism.
b) As such, it gives a clue as to the magnitude of the embolism.
when is thrombolytic therapy indicated?
a. The most widely accepted indication for thrombolytic therapy is proven pulmonary embolism with cardiogenic shock
b. Therapy may also be considered when a patient presents with systemic hypotension without shock
c. Complication due to intracranial bleed reported to occur in 2% of patients
What are the absolute and relative contraindications when treating someone with thrombolytic therapy?
ABSOLUTE •history of intracranial bleeding •CVA within past 3 months •closed head or facial trauma within past 3 months •suspected aortic dissection •active internal bleeding •uncontrolled hypertension (> 180/100)
RELATIVE
•current anticoagulation or bleeding diathesis
•surgery or invasive procedure within past 2 weeks
•recent prolonged CPR (> 10 mins)
•controlled severe hypertension
•diabetic or haemorrhagic retinopathy
•Pregnancy
What is the purpose of wearing graduated stockings? after acute DVT?
wear for 2 years
Prevent post phlebitic syndrome
How is warfarin administered?
and why must it be administer with heparin till it reaches therapeutic level?
Warfarin given for 3 months
INR maintained between 2-3
Levels below 2 not therapeutic and above 4 risk bleeding
Heparin used for prevention of hypercoagulable state due to inhibition of protein C cause the circulating gamma carboxylated factors to result in a hypercoagulable state
What are the clinical manifestation of acute massive PE?
Major haemodynamic effects; decreased CO;acute RHF
Symptoms
Faintness or collapse,central chest pain,apprehension
Severe dyspnea
Signs
Major circulatory collapse,tachycardia,hypotension,increased JVP
What is the are the clinical manifestations of acute/medium PE?
occlusion of segmental pulmonary artery leading to infarction with effusion or not
Symptom
Pleuritic chest pain(not central chest pain)
restricted breathing
hemoptysis
Signs tachycardia pleural rub crackles Low grade fever
What is the clinical manifestation of chronic PE?
chronic occlusion of pulmonary microvasculature
Symptoms
Exertional Dyspnea
Late symptoms of pulmonary hypertension or right heart failure
Signs
May be minimal in the early disease and chronically produce heaves and may even cause terminal RHF
What is paradoxical embolism and what causes it?
Passage of embolus from systemic vein into systemic artery through ASD or patent foramen ovale
Contributes to 2 % of all arterial emboli
Patent foramen ovale much more common cause
Who requires indefinite anticoagulation?
People who have recurrent DVTs or have inherited thrombophilic conditions(based on family hx)
