• Benefit: Thrombosis help stop bleeding, a hemostasis.
• Danger: A thrombus (and embolus) can block the flow of blood through a vein or artery. If it occurs in vital organs, it can become a life-threatening condition.

How does thrombosis and embolus occur? And its consequences

1. Nature of the blood flow
   • Deep vein thrombosis may occur in the legs if there is legs immobilization (causing stasis of blood flow) for a long time. It will cause affected legs swelling, pain and redness. If the clot break, it may travel to lung and obstruction blood flow through the lung, a serious condition called pulmonary embolus.
   • Blood clot may form in left atrial appendage (heart left upper chamber) if the patient has atrial fibrillation (causing stasis of blood flow in atria). If the clot break (embolus), it will travel to various part of the body causing serious consequence. The blood clot (embolus) that end up in brain will cause stroke, a critical condition.
2. Quality of the vessel wall (endothelial cell injury) 
   • Blood clot may form on foreign body in the heart or blood vessels such as metal heart valve prosthesis (no endothelial covering). If the clot break (embolus), it will travel through various part of the body causing serious consequence. The blood clot that end up in brain will cause stroke, a critical condition.
   • Blood clot will form following endothelial cell injury. This include blood clot formation following endothelial break or cholesterol plaque rupture which may lead to heart attack, a critical condition.
3. The composition of the blood
   (hypercoagulability). Some patient has condition that lead to a tendency for blood clot formation. It is usually due to genetic defect in body coagulation system such as condition called antiphospholipid syndrome. Other conditions include thrombophilia, malignancy and sepsis.

Type of thrombosis (venous or arterial)

1. Venous thrombosis
   1. Deep vein Thrombosis
   2. Pulmonary emboli
   3. Thrombosis at various locations
2. Arterial Thrombosis
   1. Stroke
   2. Myocardial infarction (Heart attack)
   3. Heart valve (Prosthesis) thrombosis
   4. Systemic emboli

Thrombosis risks

• Age, over 60 years old 
• Have had a blood clot before 
• During hormone therapy
• Have cancer or are having cancer treatment 
• Patient with atrial fibrillation
• Immobilization (post lower legs orthopedic surgery, post stroke, multiple trauma, prolong bedridden heart failure patient, riding long distance air plane)
• Have foreign (metallic) body in the heart or blood vessel such as heart valve prosthesis
• Have a condition that causes your blood to clot more easily than normal, such as antiphospholipid syndrome, malignancy. 

Management of thrombosis and embolus 

• Pharmacologic.
  • Anticoagulant (Prevent blood clot formation). There are: Heparin (Unfractionated and Low molecular weight); Factor Xa inhibitor (indirect – Fondaparinux); Factor Xa inhibitor (direct – Rivaroxaban, Apixaban, Endoxaban); Thrombin inhibitor (direct – Dabigatran); Vitamin antagonist (VKA) – Warfarin.

• ​​Non pharmacologic
  • In case of deep vein thrombosis of the lower extremities.
    • Early mobilization, 
    • Mechanical technique to improve lower extremities venous circulation
  • In case of prevention of pulmonary embolus
    • Inferior vena cava filter insertion
  • In case of atrial fibrillation and left atrial appendage thrombus
    • Left atrial appendage occluder, atrial fibrillation RF ablation, surgical maze procedure

• Pharmacologic
  • Same anticoagulants as in prophylaxis.

There are guidelines for prescribing these agent in various conditions and stages.

• Non pharmacologic
  • Embolectomy: venous, arterial, pulmonary.

• The standard venipuncture. Patient has to go to the hospital or clinic to have blood drawn for the test.
• The capillary fingertip Point Of Care Testing – POCT or Patient Self Test – PST, for home use.

Home use or Patient Self Test (PST) 

• Need good quality control for point of care INR measurement.
• Patient selection is essential.
  • Patients must have long term indication for anticoagulation therapy.
  • Patients must be willing and able to perform self-management.
  • Patients must be willing to record results accurately and attend clinics regularly for quality assurance.
  • Patients must demonstrate competence in using the instrument and interpreting the results.
  • Patients must not have shown previous noncompliance in terms of clinic attendance or medication management.
• ​ Can increase INR testing frequency and decrease complications associated with oral anticoagulation therapy.

Bangkok Anticoagulation Clinic Excellent Time in Therapeutic Range (TTR)

• Bangkok Heart Hospital Anticoagulation Clinic: 65.8 %
• Thailand average: 40 %