Thromboembolic Disorders (Deep Vein Thrombosis).pptx

Thromboembolic Disorders and DVT

1. Thromboembolic Disorders 11/8//2022 Year 5(Group B) Presented by Cadet Hein Htet Soe Cadet Thet Paing Zaw

2. Contents Definition Types Deep Vein Thrombosis (DVT) Epidemiology Etiology Pathophysiology Clinical features Investigation Management Complication 11/8//2022 Year 5(Group B)

3. Definition Thrombosis is the formation of a fibrin blood clot (thrombus) in a blood vessel. Embolus – Dislodged thrombus within vessels. Thromboembolism means obstruction of a blood vessel by a blood clot that has become dislodged from another site in the circulation. 11/8//2022 Year 5(Group B)

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5. Types of Blockage It can be divided into two main categories Venous thromboembolism Deep Vein Thrombosis Pulmonary Embolism Arterial thromboembolism 11/8//2022 Year 5(Group B)

6. Venous Thromboembolism occurs when a blood clot breaks off and blocks a vein—a blood vessel that brings blood in need of oxygen back to your heart. If the clot breaks off and lodges in a lung, it causes a serious condition known as pulmonary embolism (PE). 11/8//2022 Year 5(Group B)

7. The broader term  venous thromboembolism  generally refers to DVT, PE, or a combination of the two (called DVT/PE). With that said, thromboembolism can involve other veins of the body, both deep and superficial. Less common sites of venous thromboembolism include the arms, liver, kidneys, and brain. 11/8//2022 Year 5(Group B) Cont …

8. Arterial thromboembolism occurs when a blood clot breaks off and blocks an artery, a vessel that brings oxygen-rich blood from the heart to the rest of the body. This causes ischemia, or the restriction of blood flow and oxygen. Sometimes, infarction—tissue death due to an inadequate blood supply—also occurs. occurs in the legs and feet. Some may occur in the brain, causing a stroke, or in the heart, causing a heart attack (myocardial infarction). Less common sites include the kidneys, intestines, and eyes. 11/8//2022 Year 5(Group B)

9. Deep Vein Thrombosis Deep Vein Thrombosis is a formation of a blood clot in one the deep veins of the body usually in the leg. 11/8//2022 Year 5(Group B) 9

10. Epidemiology of DVT DVTs occur in about 1 per 1000 persons per year. It is estimated that approximately 350,000 to 600,000 people each year suffer from DVT and pulmonary embolism and at least 100,000 deaths may be directly or indirectly related to these diseases. 11/8//2022 Year 5(Group B)

11. 11/8//2022 Year 5(Group B) Etiology of DVT VIRCHOW’s Triad

12. 11/8//2022 Year 5(Group B) Venous Stasis Hypercoagulability Endothelial Injury VIRCHOW’s Triad Prolonged bed rest (4 days or more) A cast on the leg Limb paralysis from stroke Spinal cord injury Extended travel in a vehicle Varicose veins Pregnancy Surgery and trauma – 40% of all thromboembolic disease Malignancy Increased estrogen (OCP, HRT) Inherited disorders of coagulation – Deficiency of protein S, protein C, anti-thrombin III Acquired disorders of coagulation – Nephrotic syndrome, Anti-phospholipid antibodies Polycythemia Dehydration Trauma Surgery Smoking Hypertension Invasive procedure Iatrogenic causes – Central venous catheters Subclavian Internal Jugular lines These lines cause of upper extremity DVT

13. Pathophysiology of DVT Vessel trauma stimulates the clotting cascade Platelet aggregates at the site Platelet and fibrin form the initial clot RBC are trapped in the meshwork 11/8//2022 Year 5(Group B)

14. CONT….. The thrombus propagates in the direction of the blood flow Inflammation is triggered causing thrombophlebitis Pieces of thrombus may break loose and travel through circulation emboli Fibroblasts invade the thrombus, scarring vein wall and destroying valves 11/8//2022 Year 5(Group B)

15. Common Clinical Manifestations of DVT Calf muscle pain or tenderness Swelling with pitting oedema Increased skin temperature and fever Superficial venous dilatation Cyanosis can occur with severe obstruction 11/8//2022 Year 5(Group B)

16. Clinical Examination of DVT Homans' test Dorsiflexion of foot elicits pain in posterior calf. However, it must be noted that it is of little diagnostic value and is theoretically dangerous because of the possibility of dislodgement of loose clot. Pratt's sign Squeezing of posterior calf elicits pain. 11/8//2022 Year 5(Group B)

17. Well Score or Criteria(Possible Score-2 to 8) Active cancer (treatment within last 6 months or palliative) Calf swelling >3 cm compared to other calf (measured 10 cm below tibial tuberosity) Collateral superficial veins (non-varicose) Pitting edema (confined to symptomatic leg) 11/8//2022 Year 5(Group B)  1 point  1 point  1 point  1 point

18. CONT…. Swelling of entire leg Localized pain along distribution of deep venous system Paralysis, paresis, or recent cast immobilization of lower extremities Recently bedridden > 3 days, or major surgery requiring regional or general anesthetic in past 4 weeks Alternative diagnosis at least as likely (cellulitis, calf strain, Baker Cyst, or postoperative swelling) 11/8//2022 Year 5(Group B)  1 point  1 point  1 point  1 point  Subtract 2 points

19. Interpretation Score of 2 or higher - deep vein thrombosis is likely. Consider imaging the leg veins. Score of less than 2 - deep vein thrombosis is unlikely. Consider blood test such as D-dimer test to further rule out deep vein thrombosis. 11/8//2022 Year 5(Group B)

20. Investigations Blood Test D-dimer (very sensitive but not very specific) In a low-probability situation, current practice is to commence investigations by testing for D-dimer levels. This cross-linked fibrin degradation product is an indication that thrombosis is occurring, and that the blood clot is being dissolved by plasmin. A low D-dimer level should prompt other possible diagnoses such as a ruptured Baker's cyst, if the patient is at sufficiently low clinical probability of DVT. 11/8//2022 Year 5(Group B)

21. Other Blood Tests complete blood count Primary coagulation studies: PT, APTT, Fibrinogen liver enzymes renal function and electrolytes. 11/8//2022 Year 5(Group B)

22. Imaging the leg veins Doppler Ultrasonography , Compression ultrasound scanning of the leg veins, combined with duplex measurements (to determine blood flow), can reveal a blood clot and its extent (i.e. whether it is below or above the knee). 11/8//2022 Year 5(Group B)

23. Duplex Ultrasonography , due to its high sensitivity, specificity and reproducibility, has replaced venography as the most widely used test in the evaluation of the disease. This test involves both a B mode image and Doppler flow analysis. Intravenous venography , which involves injecting a peripheral vein of the affected limb with a contrast agent and taking X-rays, to reveal whether the venous supply has been obstructed. Because of its invasiveness, this test is rarely performed. 11/8//2022 Year 5(Group B)

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25. Management and Intervention Primary Prevention A combination of mechanical and pharmacological measures can be used to prevent DVT. Mechanical prophylaxis involves the use of graduated compression stockings (GCS), intermittent pneumatic compression (IPC) and venous foot pumps to improve blood flow in the deep veins of the leg. Common agents for pharmacological prophylaxis include Warfarin, subcutaneous unfractionated heparin (UFH) and low-molecular-weight heparins (LMWH).DVT prevention is most effective when both methods are used simultaneously. I n medical and surgical patients ambulation and exercises involving ankle dorsiflexion are encouraged to further minimize venous stasis. 11/8//2022 Year 5(Group B)

26. Early Ambulation The earlier the better Lower incidence of VTE, Shorter length of stay, earlier return to the community, fewer complications and lower 6 months mortality Used with elastic stockings for low risk patients as only form of prophylaxis 11/8//2022 Year 5(Group B)

27. Elastic stockings Improve venous flow and reduce vessel wall damage secondary to passive venous dilatation Fit properly, above knee and continue use throughout hospitalization and rehab period. Not recommended as solo prophylaxis for moderate and high risk patients 11/8//2022 Year 5(Group B)

28. Intermittent Pneumatic Compression Devices Exact mechanism whereby they prevent VTE is unclear Reduce venous stasis Promote the clearance of pro-thrombotic coagulation factors Possibly increase local plasminogen activator Only effective when used continuously Not recommended as the primary agent in high risk patients and Hip and knee surgery 11/8//2022 Year 5(Group B)

29. Secondary prevention Primary objectives prevent pulmonary embolism reduced morbidity prevent or minimize the risk of developing the post phlebitis syndrome 11/8//2022 Year 5(Group B)

30. Medical Treatment Anticoagulation Unfractionated heparin Low molecular weight heparin Warfarin Thrombolytic therapy 11/8//2022 Year 5(Group B) Initial treatment of DVT is with low molecular-weight heparin or unfractionated heparin for at least 5 days, followed by warfarin (target INR, 2.0-3.0) for at least 3 months

31. Unfractionated heparin Initial bolus 7500 to 10,000 IU followed by continuous in infusion to 1000 to 1500 IU/hr. Infusion rate adjust so that aPTT is approx. twice the control value. Every 6 hrs aPTT monitored till therapeutic range is reached Duration : 5 days Discontinue when platelet count <75,000 11/8//2022 Year 5(Group B)

32. Low molecular weight heparin Effective and better than conventional heparin Administered SC in fixed doses once or twice daily Duration : 7-14 days Anticoagulated effect by inhibiting the activated factor X Hemorrhagic complication doesn’t occur Currently for LMWH are available Enoxaparin Tinazaparin Dalteparin Nadroparin 11/8//2022 Year 5(Group B)

33. Warfarin To be taken along with heparin for initial 4 to 5 days Dose adj to maintain prothrombin time at INR 2.0 to 3.0 Continued for 3 to 6 months for pts with acute idiopathic DVT For recurrent DVT/PE low intensity warfarin continued indefinitely maintaining INR 1.5 to 2.0 11/8//2022 Year 5(Group B)

34. Thrombolytic therapy Early administration Prompt resolution of symptoms Accelerate clot lysis Preserve venous valves Decrease the potential for developing post phlebitis syndrome Doesn’t prevent clot propagation or rethrombosis 11/8//2022 Year 5(Group B) Heparin and oral anti coagulant therapy must follow a course of thrombolysis E.g. streptokinase, urokinase. tPA (alteplase)

35. Direct thrombin inhibitor Lepirudin or aragatroban Used when heparin is contra indicated due to HIT (heparin induced thrombocytopenia) 11/8//2022 Year 5(Group B)

36. Surgical Treatment Indicated when anticoagulant therapy is ineffective, unsafe or contraindicated Major surgical procedures : clot removal and partial interruption of IVC to prevent PE Thrombectomy Filters for DVT 11/8//2022 Year 5(Group B)

37. 11/8//2022 Year 5(Group B) Contraindications to Anticoagulants

38. Thrombectomy To restore venous patency and valvular function. Alone it isn’t indicated because rethrombosis is frequent Heparin therapy is a necessary adjunct Best reserved for patients with massive IF vein thrombosis when limb viability is at risk. 11/8//2022 Year 5(Group B)

39. Filters for DVT First suggested by Trousseau in 1868 Today introducing intracanal devices percutaneously and floating them into position with fluoroscopy is the procedure of choice for filter placement Indication for filer placement Severe hemorrhage complications of anticoagulant therapy Absolute contra indications to anticoagulation Failure of anticoagulation such us new or recurrent VTE or PE 11/8//2022 Year 5(Group B)

40. Potential Complication Pulmonary emboli – most serious complication of DVT Chronic venous insufficiency – Long term DVT can degenerate the venous valves Post phlebitis syndrome – Long term complication of DVT which occurs due to damage and scarring to the veins and is characterized by swelling, discomfort and skin pigmentation in the affected area 11/8//2022 Year 5(Group B)

41. References 11/8//2022 Year 5(Group B)

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