DEEP VENOUS THROMBOSIS

1. DEEP VENOUS THROMBOSIS

2. Definition • formation of a blood clot in one of the deep veins of the body, usually in the leg

3. Anatomy

4. Etiology and risk factors 3 main factors contribute in development of DVT • Stasis • Endothelial injury • Hypercoagulability

5. Venous stasis • prolonged bed rest (4 days or more) • a cast on the leg • limb paralysis from stroke or spinal cord injury • extended travel in a vehicle • heart failure

6. Hypercoagulability • Surgery and trauma - responsible for up to 40% of all thromboembolic disease • Malignancy • Increased estrogen (due to a fall in protein ‘S) Increased estrogen occurs during • all stages of pregnancy • the first three months postpartum, • after elective abortion, and • during treatment with oral contraceptive pills

7. Inherited disorders of coagulation • deficiencies of protein ‘S’, • protein ‘C’ and • antithrombin III.

8. Acquired disorders of coagulation • nephrotic syndrome results in urinary loss of antithrombin III, this diagnosis should be considered in children presenting with thromboembolic disease • Antiphospholipid antibodies accelerate coagulation and include the lupus anticoagulant and anticardiolipin antibodies.

9. Inflammatory processes, such as systemic lupus erythematosus (SLE), sickle cell disease, and inflammatory bowel disease (IBD), also predispose to thrombosis, presumably due to hypercoagulability

10. Symptoms: • Dull pain, heaviness, oedema and warm limb • With extensive DVT:-massive oedema, cyanosis, dilated superficial collateral veins and low grade fever. • With ilio-femoral DVT:- • Phlegmasiaceruleadolens(cyanosed limb due to obstructed vein) • Phlegmasia alba dolens(pale, pulseless cold limb due to concurrent arterial spasm) AND THESE TWO UPPER CASES ARE LIMB THREATENING CONDITION!!

11. Phlegmasia cerulea dolensVenous gangrene

12. Signs • HOMAN'S sign (tenderness during passive dorsiflexion of foot). And it was contraindicated because of it’s role in thrombus deattachment and thus emobilization • Hotness, cyanosis, oedema (non-pitting)

13. Diagnostic Studies - Clinical examination alone is able to confirm only 20-30% of cases of DVT - Blood Tests • the D-dimer - have predictive value for DVT • INR - useful for guiding the management of patients with known DVT who are on warfarin (Coumadin)

14. D-dimer • D-dimer is a specific degradation product of cross-linked fibrin. Because concurrent production and breakdown of clot characterize thrombosis, patients with thromboembolic disease have elevated levels of D-dimer • three major approaches for measuring D-dimer • ELISA • latex agglutination • blood agglutination test - SimpliRED

15. False-positive D-dimersoccur in patients with: • recent (within 10 days) surgery or trauma, • recent myocardial infarction or stroke, • acute infection, • disseminated intravascular coagulation, • pregnancy or recent delivery, • active collagen vascular disease • metastatic cancer

16. Imaging Studies • Invasive • venography, • radiolabeled fibrinogen • Noninvasive • ultrasound, • plethysmography, • MRI techniques

17. Imaging studies: *The standard tool for diagnosis is phlebography using fluoroscope. The use of this study limited by is complications which are allergy, nephropathy and phlebitis. *Duplex ultrasound: Test of choice Sensitivity and specificity >95% Able to detect other pathology like BAKER cyst.

18. Venography • "gold standard” modality for the diagnosis of DVT Advantages • venography is also useful if the patient has a high clinical probability of thrombosis and a negative ultrasound, • it is also valuable in symptomatic patients with a history of prior thrombosis in whom the ultrasound is non-diagnostic.

19. Venogram shows DVT

20. Ultrasonography • color-flow Duplex scanning is the imaging test of choice for patients with suspected DVT • inexpensive, • noninvasive, • widely available • Ultrasound can also distinguish other causes of leg swelling, such as tumor, popliteal cyst, abscess, aneurysm, or hematoma.     

21. clinical limitations • reader dependent • Duplex scans are less likely to detect non-occluding thrombi. • During the second half of pregnancy, ultrasound becomes less specific, because the gravid uterus compresses the inferior vena cava, thereby changing Doppler flow in the lower extremities

22. The finding are: • Acute DVT: • Absence of spontaneous flow. • Loss of flow variation with respiration. • Failure to increase the flow after distal augmentation. • Not visible thrombi (anechoic thrombi). • Chronic DVT: Not well established Narrow vein Patent collateral Visible thrombi

23. Color duplex scan of DVT

24. The only disadvantage of duplex study is that, it is highly operator dependant!!!

25. Magnetic Resonance Imaging • It detects leg, pelvis, and pulmonary thrombi and is 97% sensitive and 95% specific for DVT. • It distinguishes a mature from an immature clot. • MRI is safe in all stages of pregnancy.

26. Differential diagnoses: • Unilateral limb involvement: muscular strain, tendon rupture, cellulites, lymphodema or retroperitoneal fibrosis pressing over the vein. • Bilateral limb involvement: liver, heart or renal failure or IVC obstruction.

27. Complication of DVT • Recurrent DVT • Varicose vein • Chronic venous insufficiency • Post phlebitic syndrome (pain, oedema and ulceration) • PE

28. Patient with suspect symptomatic Acute lower extremity DVT negative Venous duplex scan Low clinical probability observe High clinical probability positive negative Evaluate coagulogram /thrombophilia/ malignancy Repeat scan / Venography IVC filter Anticoagulant therapy contraindication yes No pregnancy LMWH OPD LMWH + warfarin hospitalisation UFH Compression treatment

29. Management • The aim of management is: Prophylaxis against DVT Treatment of ongoing DVT

30. Methods of Prophylaxis: 1) Mechanical • Leg elevation • Graded compression stocking • Early ambulation • Pneumatic compression boo.

31. 2) Pharmacological agents: • Aspirin (anti platelet factor) not recommended currently. • Dextran solution (40 and70) branched polysaccharide. Decrease platelets adhesiveness and aggregation. Disadvantages: • Increase rate of bleeding • Pulmonary edema (due to overload) • Allergic reaction in 1% Recommended dose is15-20 cc/h IV infusion before surgery.

32. Warfarine (coumadine):- Decrease incidence of DVT by 66% and PE by 80%. Disadvantages: • Sever hemorrhage • Must be started 2-3 days preoperative. • Require careful monitoring for PT.

33. Warfarine nomograph

34. Heparin Unfractionated heparin: • Inhibits AT III and potentiate disintegration of thrombi that form while it administered • Low dose regimen is 5000 IU twice daily SQ two hours pre-operatively then q12hours post operative till the patient is completely ambulating. • For morbidly obese patient: - micro-heparin drip at 1u/kg/hour • Disadvantages: Risk of bleeding Thrombocytopenia (rare) • Contraindicated in patient with actively bleeding peptic ulcer, uncontrolled HTN, bleeding disorder or recent use of ASA

35. Heparin-dihydroergotamine (DHE) combination: • Cause vasoconstriction of capacitance veins and thus increase the venous return. • Particular effectiveness in orthopedic cases. • Contraindicated in case of hypotension, IHD and peripheral arterial occlusive diseases. Low molecular weight (enoxaparin): • Lesser effect on thrombin and platelets aggregation. • Longer life time so the dose will be once daily. • More expensive than unfractionated heparin.

37. Heparin nomograph

38. Fibrinogen-depleting compound • New class of anticoagulants but not well known. Prophylactic IVC filter placement. • Also known as Greenfield filter. • Used in high risk patient when other methods are contraindicated. • Effective in preventing PE not DVT.

39. An approach to Prophylaxis 1.determine patient at risk • Low risk (<40 years old, ambulating, minor surgery) • Moderate risk (>40 years old, abdominal, pelvic or thoracic surgery) • High risk (>60years old, prior DVT or PE malignancy, orthopedic surgery hypercoagulability state).

40. 2. prohylaxis of choice Encourage all patients to ambulate as soon as possible • Low risk patient don't need prophylaxis. • Moderate risk pneumatic compression boot or low dose heparin prophylaxis. • High risk combination of pneumatic compression boot and low dose heparin prophylaxis or Dextran. Coumadine or IVCfilter are considered. Ophthalmology or neurosurgery patient are NOT candidates for prophylaxis.

41. Treatment of DVT A: - anticoagulation • Heparin bolus 100-150 u/kg IV stat then followed by constant infusion of 1000 u/hour with checking aPTT q 4-6hours and keeping the ratio 50-70sec. • Coumadine (Warfarine) usually started at day 3-5 after initial heparin is given and continue for 3-6 months . PT should be 17-20sec. and INR 2.0-2.5.

42. Duration of anticoagulation in patients with deep vein thrombosis • Transient cause and no other risk factors: 3 months • Idiopathic: 3-6 months • Ongoing risk for example, malignancy: 6 -12 months • Recurrent pulmonary embolism or deep vein thrombosis: 6-12 months • Patients with high risk of recurrent thrombosis exceeding risk of anticoagulation: indefinite duration (subject to review)

43. B:-thrombolytic treatment( alteplase, streptokinase, urokinase) Promote rapid thrombus lysis. Used in cases of sever PE . They have more bleeding complication. C:-venal cava interruption (IVC filter) • Prevent further embolism of thrombi D:- venous thrombectomy • May be necessary in venous gangrene and septic thrombosis.

44. Thrombolytic therapy for DVT Advantages include • prompt resolution of symptoms, • prevention of pulmonary embolism, • restoration of normal venous circulation, • preservation of venous valvular function, • and prevention of postphlebitic syndrome.

45. Thrombolytic therapy does not prevent • clot propagation, • rethrombosis, or • subsequent embolization. Heparin therapy and oral anticoagulant therapy always must follow a course of thrombolysis.

46. Thrombolytic therapy is also not effective once the thrombus is adherent and begins to organize The hemorrhagic complications of thrombolytic therapy are formidable (about 3 times higher), including the small but potentially fatal risk of intracerebral hemorrhage.

47. Catheter directed-thrombolysis • Consider in: Acute< 10 days iliofemoral DVT. • Long-term benefit in preventing post-phlebitic syndrome is unknown.

48. Filters for DVT Indications for insertion of an inferior vena cava filter : • Pulmonary embolism with contraindication to anticoagulation • Recurrent pulmonary embolism despite adequate anticoagulation

49. Filters for DVT Controversial indications: • Deep vein thrombosis with contraindication to anticoagulation • Deep vein thrombosis in patients with pre-existing pulmonary hypertension • Free floating thrombus in proximal vein • Failure of existing filter device • Post pulmonary embolectomy

50. Filters for DVT • Inferior vena cava filters reduce the rate of pulmonary embolism but have no effect on the other complications of deep vein thrombosis.