1. Thromboembolism refers to the formation of blood clots (thrombosis) that can break off and block blood vessels (embolism). It is caused by changes to blood flow, blood composition, and vessel walls.
2. The risk of thromboembolism increases with age as cardiovascular changes occur, including increased clotting and stiffer arteries. Common types are venous thrombosis and arterial thrombosis.
3. Treatment involves blood thinners, thrombin inhibitors, antiplatelet drugs, and thrombolytics to dissolve clots, with precautions needed due to bleeding risks, especially in the elderly.
2. Ageing and the Cardiovascular System
• Cardiovascular changes occur with ageing among
individuals normally considered healthy.
• Heart tends to get enlarged and the pumping action
decreases.
• Large elastic arteries exhibit increases in wall thickness,
become dilated and stiffer.
• Blood vessels loose elasticity, resulting in swelling of the
feet, high blood pressure and heart failure.
• Level of coagulation factors increase, which increases
tendency of the blood to clot.
3. Ageing and the Cardiovascular System
• These changes can increase the incidence of conditions in
the elderly, such as:
• Atherosclerosis
• Hypertension
• Stroke
• Thromboembolism
• Heart failure
• Aging, per se, is a major risk factor for these diseases.
5. Thrombosis and Embolism
• Thrombosis is the formation of a blood clot inside a blood
vessel, obstructing the flow of blood.
• Sequence of events is as follows:
1. Blood vessel is injured.
2. Body uses platelets and fibrin to form a clot - preventing blood loss.
3. If the clotting is severe and part of the clot breaks free, an embolus is
formed.
4. An embolus can then lodge itself anywhere else in the body.
5. Thromboembolism is the combination of thrombosis and its main
complication, embolism.
• If proper conditions present themselves, blood clots will form
in absence of blood vessel injury.
6. Thrombosis and Embolism
• Upon diagnosis, there are often
many emboli of different age, size
and at different sites.
• A thrombus occupying > 75% of
surface area of the lumen of an
artery reduces tissue blood flow
enough to cause:
• Hypoxia: Oxygen deficiency.
• Accumulation of metabolic products
(e.g. lactic acid).
• > 90% obstruction can result in:
• Anoxia: complete deprivation of
oxygen.
• Infarction: a mode of cell death.
7. Causes
• Thromboembolism is caused by one or more of the
following – Virchow’s Triad:
• Blood composition:
• Thicker blood.
• Increased blood clotting, as in congenital conditions, hormone therapy
and birth control pills.
• Quality of the vessel wall:
• Damage to vessel’s inner lining.
• Due to injury, high blood pressure, ageing, etc…
• Nature of blood flow:
• Sluggish or slow flow.
• Due to lack of motion, prolonged traveling, etc…
10. 1. Venous thrombosis:
• Formation of a thrombus within a vein.
• Linked with its immediate complication, pulmonary
embolism.
• Untreated VTE has a 30% fatality rate.
a) Portal Vein Thrombosis:
• Affects hepatic portal vein.
• Leads to portal hypertension and reduced
blood supply to liver.
b) Renal Vein Thrombosis:
• Leads to reduced drainage from the kidney.
• Symptoms include:
• Kidney failure.
• High blood pressure.
11. 1. Venous Thrombosis
c) Deep Vein Thrombosis (DVT):
• Formation of a blood clot within a deep vein.
• Most commonly affects leg veins – femoral vein.
• Classical signs of DVT: swelling, pain and redness.
• In the long term, it can lead to post-phlebitic syndrome - dermatitis,
cellulites, varicose veins, skin pigmentation and chronic ulceration of
lower leg.
13. 2. Arterial Thrombosis:
• Formation of a thrombus within an artery.
• Possible causes include atherothrombosis and atrial fibrillation.
• Arterial embolism can result in an
infarction of almost any body organ.
a) Ischemic Stroke:
• A thrombus in arteries of the brain.
• Results in a rapid decline in brain
function due to disturbance of blood
flow.
• Symptoms include:
• Sudden weakness or numbness in one
side of the body.
• Sudden dimness or loss of vision.
• Sudden slurred speech or loss of speech.
14. 2. Arterial Thrombosis
b) Myocardial Infarction:
• Caused by an infarct, often due to obstruction of coronary
artery by a thrombus.
• If diagnosed within 12 hours of the initial attack, thrombolytic
therapy is initiated.
• Symptoms include:
• Sudden chest pain
• Dyspnea
• Palpitations and sweating
15. Diagnosis
• Medical history.
• Physical exam.
• Diagnostic tests:
• Ultrasound
• D-dimer test
• Venography
• Blood tests.
• Lung Ventilation Perfusion Scan – in case
of pulmonary embolism.
16. Prophylaxis
• Thromboprophylaxis (prevention of thrombosis) is increasingly
emphasized.
• Thrombosis and embolism can be partially prevented with
anticoagulants in those deemed at risk.
• Generally, a risk-benefit analysis is required, as all
anticoagulants lead to a small increase in the risk of major
bleeding.
• Elderly are usually at higher risk of suffering from such
bleeding or hemorrhage.
• For example, in atrial fibrillation, the risk of stroke needs to
outweigh the small but known risk of major bleeding
associated with the use of warfarin.
17. Treatment
• Treatment with heparin and thrombolytic agents is clearly
effective in patients age 65 and older, despite increased
susceptibility of hemorrhagic complications.
• Careful evaluation of individual hemorrhagic risk, dosage
modification, and careful laboratory monitoring may decrease
the number of clinically significant bleedings without impairing
therapeutic results.
18. Treatment
• Main goals of treatment:
• Stopping the clot from getting bigger.
• Preventing embolism.
• Reducing chance of having another blood clot.
• Pharmacological treatment:
• Anticoagulants
• Thrombin inhibitors
• Antiplatelet Drugs
• Thrombolytics (fibrinoyltics)
• Other treatment:
• Vena cava filter
• Graduated compression stockings
19. 1. Anticoagulants
• Include:
• Warfarin (Oral)
• Heparin (IV)
• Most common treatment, also known as blood thinners.
• Decrease blood’s ability to clot, and stops existing clots from
getting bigger.
• Can’t break up already formed clots.
• Since heparin acts quickly and warfarin takes 2 to 3 days to
work, combination treatment is useful where heparin is
started until warfarin starts to work, then heparin in stopped.
• Treatment duration often lasts from 3 to 6 months.
• Most common and threatening side effect is bleeding or
hemorrhage.
20. 1. Anticoagulants
• People treated with blood thinners usually have regular blood
tests to measure their blood's ability to clot, including PT, PTT
and INR tests.
• Coumarins:
• Vitamin K antagonists, such as Warfarin.
• Helps prevent future blood clots and reduces risk of embolism.
• Close monitoring of degree of anticoagulation (INR) is required to avoid
hemorrhage.
a) Heparin and derivatives:
• Antithrombin III activator – blocks thrombin from clotting blood.
• Low molecular weight heparin is preferred in elderly because of:
• More predictable plasma levels.
• Lower risk of bleeding.
• Lower risk of heparin-induced thrombocytopenia.
21. 2.Thrombin Inhibitors
• Interfere with the blood clotting process.
• Directly inhibits the enzyme thrombin.
• Used to treat blood clots in patients with contraindications
to heparin.
22. 3. Antiplatelet Agents
• Mainly used in arterial thrombosis.
• Act by inhibiting the activity of platelets.
• Members include:
• Aspirin
• Thienopyridines: Clopidogrel and Ticlodipine
• Low-dose Aspirin therapy has a modest antithrombotic effect,
preventing approximately 25% of cardiovascular events.
• Modest effect is the result of other platelet activators, not inhibited
by Aspirin.
• Thienopyridines are marginally superior to Aspirin in preventing
atherothrombosis in the cerebral and peripheral arteries, but not in
the coronary arteries.
• Adverse effects include:
• Risk of bleeding
• Gastrointestinal bleeding
23. 4. Thrombolytics
• They work on quickly dissolving an existing blood clot.
• Used to clear blocked arteries and avoid permanent damage to
tissues.
• Used only in life-threatening situations, due to risk of sudden
bleeding.
• Contraindications:
• Absolute:
• Active bleeding.
• Uncontrolled high blood pressure.
• Previous intracranial bleeding.
• Relative:
• Current anticoagulant use.
• Pregnancy.
• Active peptic ulcer.
• Severe hypertension
24. 4. Thrombolytics
• Types:
• Recombinant tissue plasminogen activator (rt-PA)
• Streptokinase
• Urokinase
• Anistreplase
• Streptokinase:
• Given as IV infusion.
• May be preferable to rt-PA in elderly due to lower risk of stroke and
cerebral hemorrhage.
• Best outcome is achieved within the first 60 minutes, but may
extend up to 6 hours after initiation of symptoms.
• Except for streptokinase, thrombolytics are often given in
combination with intravenous heparin.
25. 5. Vena Cava Filter
• A surgical device implanted into
inferior vena cava.
• Prevents fatal pulmonary embolism.
• Works to trap released emboli.
• Used in case of:
• Contraindication to anticoagulation
therapy.
• Failure of anticoagulation therapy.
• Presence of large clots.
• Patients at high risk of pulmonary
embolism.
26. 6. Graduated Compression Stockings
• Compression stockings are constructed using elastic fibers or
rubber.
• These fibers help compress the limb, aiding in circulation.
• Used in prevention of:
• DVT
• Post-thrombotic DVT symptoms.
27. Precautions
• Blood-thinning medications can sometimes
cause internal or external bleeding,
especially in the elderly.
• Internal bleeding can occur in the digestive
system or the brain.
• Signs and symptoms of bleeding in the
digestive tract:
• Bright red vomit.
• Bright red blood in stool, or black, tarry stools.
• Pain in abdomen.
28. Precautions
• Signs and symptoms of bleeding in the
brain:
• Severe pain in head.
• Sudden changes in vision.
• Sudden loss of movement in arms and legs.
• Memory loss or confusion.
• Seek treatment immediately if you suffer
excess bleeding after injury.
• Talk to your doctor before taking any drugs,
including OTCs such as aspirin, which can
contribute to blood thinning.