venous thombois-1 for final year students

Venous Thrombosis

1. VENOUS THROMBOSIS Dr Nilutpal Gogoi . Assistant Prof. of Surgery, GMCH

2. Defination : venous thrombosis is formation of blood clot (thrombus) within a vein. Aeitiology – 3 factors Stasis – Varicose vein ,immobility ,pregnancy ,malignancy, trauma or surgery specially of pelvis ,recent MI Endothelial injury –smoking ,infection ,trauma Hypercoagulability –protein C ,protein S deficiency ,malignancy ,pregnancy ,IBD ,trauma

3. Types of venous thrombosis 1.Thrombophlebitis (superficial vein thrombosis) 2.Phlebothrombosis (deep vein thrombosis/DVT)

4. Thrombophlebitis Clinical features Pain & Redness Palpable cord-like veins localized warmth and tenderness Thrombophlebitis migrans or Trousseau's syndrome - -- When Thrombophlebitis affect one vein after another. Its seen in Buergers ’ disease & visceral cancers like Pancreatic cancer.

5. Treatment Hot bath or compress Elastic support or crepe bandage c . Antinflammatory drugs e.g. Aspirin, Trypsin etc d . Antibiotics e.g Amoxicillin- Clauvanic acid ( AUGMENTIN), Cefuroxim e etc

6. Deep vein thrombosis(DVT) or Phlebothrombosis

7. More than 100 years ago, Rudolf Virchow described a triad of factors - VIRCHOW TRIAD - responsible for V. Thrombosis

8. Venous stasis prolonged bed rest (4 days or more) A cast on the leg Limb paralysis/ stroke spinal cord injury extended travel in a vehicle Hypercoagulable state Surgery and trauma - 40% of all thrombo embolic disease Malignancy - Up to 15% of cancer pts presents with DVT. Highest incidence: mucin -producing adenocarcinomas of pancreas & GIT, lung and ovary. increased estrogen Inherited disorders of coagulation - Deficiencies of protein-S, protein-C, anti-thrombin III. Acquired disorders of coagulation- Nephrotic syndrome, Anti- phospholipid antibodies

9. Endothelial Injury Trauma Surgery Invasive procedure

10. Clinical Features Symptoms - -- 1) Aching pain aggravated by muscular activity ( absence of claudication , which is present in arterial disease) 2) 60% of cases are asymptomatic . Signs --- 1) Swelling ,tenderness, Pitting Oedema , Increased skin temp. & fever.

11. Homans ’ sign —passive dorsiflexion of foot with leg extended will cause pain in the calf . Moses’ sign- - - DVT involving posterior tibial veins . Pain when calf muscle is compressed forwards against tibia , but not when calf muscle is compressed from side to side Phlegmasia alba dolens -- Thrombosis of ilio femoral vein causes pain ,massively swollen leg ,pitting oedema & blanching. Phlegmasia cerulea dolens -- further progression of oedema causing arterial flow compromise(painful blue leg) . Unless flow is restored venous gangrene can develop .

12. Symptomatic deep vein thrombosis is "tip of the iceberg"

13. Without prophylaxis the incidence of deep vein thrombosis is about – 14% in gynaecological surgery 22% in neurosurgery 26% in abdominal surgery 15% to 40% Urologic surgery 45%-60% in patients undergoing hip and knee surgeries.  

14. Pathophysiology Vessel trauma stimulates the clotting cascade. Platelets aggregate at the site particularly when venous stasis present Platelets and fibrin form the initial clot RBC are trapped in the fibrin meshwork meshwork.

15. Wells Clinical Prediction Guide It is an additional tool to diagnosis rather than being a stand-alone test. Wells Clinical Prediction Rule for Deep Venous Thrombosis (DVT) Clinical feature Points Active cancer (treatment within 6 months, or palliation) 1 Paralysis, paresis, or immobilization of lower extremity 1 Bedridden for more than 3 days because of surgery (within 4 weeks) 1 Localized tenderness along distribution of deep veins 1 Entire leg swollen  1 Unilateral calf swelling of greater than 3 cm (below tibial tuberosity ) 1 Unilateral pitting edema 1 Collateral superficial veins 1 Interpretation High probability: ≥ 3 (Prevalence of DVT - 53%) Moderate probability: 1-2 (Prevalence of DVT - 17%) Low probability: ≤ 0 (Prevalence of DVT - 5%)

16. Diagnosis Clinical examination alone is able to confirm only 20-30% of cases of DVT Blood Tests The D- dimer Imaging Studies

17. The D- dimer ( Degradation product of cross linked fibrin ) 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 Various kits have a 93-95% sensitivit y and about 50% specificity in the diagnosis of thrombotic disease. False-positive D- dimers occur 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 or metastatic cancer

18. Imaging Studies Invasive venography – Rarely used now. radiolabeled fibrinogen - I 125 -labeled fibrinogen , m ore commonly used in research . Can distinguish new from old clot. from old clot . Noninvasive Doppler ultrasound- MC used. Less likely to detect non occluding clot and new from old clot. Plethysmography - Venous return in L.L is occluded by inflation of a BP cuff, and then the cuff is released, resulting in a decrease in calf blood volume. Any obstruction of the proximal veins diminishes the volume change.

19. MRI- 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. Test may not be appropriate for patients with pacemakers or other metallic implants .( Currently MRI capable implants are available)

20. TREATMENT General Measures Bed rest & Leg elevation Encourage the patient to perform gentle foot & leg exercises every hour. Increase fluid intake upto 2 l/day unless contraindicated. Avoid deep palpation .

21. Specific Treatment 1) Anticoagulation - LMW heparin for at least 5 days, followed by warfarin for avg. 3-6 months. Acts by inhibiting factor Xa , so safer. e.g. Enoxaparin , Deltaparin etc given SC or IV Warfarin Interferes with hepatic synthesis of vitamin K-dependent coagulation factors . Oral dose of 2-10 mg/d. Dose individualized and adjusted to maintain INR between 2-3 Heparin acts by activating Antithrombin III ( body's primary anticoagulant)-> inhibit thrombin-> inhibits factor X, factor IX in the coagulation process. Dose: Loading dose of 50-100 units/kg( 5000-10000IU) of heparin followed by a constant infusion of 15-25 units/kg/hr.

22. 2) Thrombolytic therapy for DVT followed by LMWH + Warfarin Drugs used : TPA(tissue plasminogen activator), Urokinase Reserved for exceptional cases e.g. limb-threatening ischemia caused by phlegmasia cerulea dolens because of higher complications. when anticoagulant therapy is ineffective, contraindicated & to prevent embolism PCDT( Percutaneous catheter directed thtombolysis ) under C-Arm guidance

23. 3) IVC Filters for DVT Significant bleeding complication of anticoagulation therapy. Pulmonary embolism with contraindication to anticoagulation. Recurrent thrombo -embolic complication despite adequate anticoagulation therapy.

24. 4) Open Surgery ( Thrombectomy ) Rarely done nowadays because of increased risk of re-thrombosis.

25. Compression Stokings ( used along with medications) Relieve symptoms by improving Blood flow & Preventing Oedema Tight at feet & gradually loose upwards Class of Stockings - Class 1( 14-17 mm): Varicose vein with mild oedema - Class 2( 18-24mm): Varicose vein with ulcer, DVT - Class 3( Ulcer recurrence, chronic venous insufficiency)

26. Prophylaxis High risk Patients- Diabetic pts over 40 or age > 60. Long duration surgery(main ortho , Urology, Cancer) H/O coagulation & venous/ arterial diseases Obese persons Mechanical measures - elastic compression stocking Pneumatic compression Pharmacological treatment- Peri operative LMWH

27. Pulmonary embolism Pulmonary embolism ( PE ) is a blockage of the pulmonary artery or one of its branches by a substance(thrombus) that has traveled from elsewhere in the body through the bloodstream .

28. Causes-- Usually a blood clot (from DVT) that breaks off and migrates to the lung. Other causes are--- air bubble, fat droplet, amniotic fluid

29. symptoms Sudden onset dyspnea tachypnea pleuritic chest pain ( worsened by breathing ) cough and hemoptysis Severe cases: Cyanosis, collapse and circulatory instability because of right ventricular dysfunction .

30. SIGNS on clinical examination Respiratory System : lungs are usually normal. Occasionally, a pleural friction rub. CVS: Strain on the right ventricle may be detected as a loud pulmonary component of the second heart sound and/or raised jugular venous pressure

31. Diagnosis Clinical finding CT pulmonary angiography ECG is to rule out other causes of chest pain

32. Treatment A nticoagulant medication: heparin & warfarin . Severe cases may require thrombolysis using tissue plasminogen activator ( tPA ) or Surgical intervention via pulmonary thrombectomy

33. THANKS Next Class Pheripheral arterial diseases

34. Amputation Amputation is a procedure where a part of the limb is removed through one or more bones .

35. Ideal amputation stump Firm Smooth Cone bearing & tapering distally No terminal scar Flap should have adequate blood supply Adequate lenght Conical stump Not an ideal stump. Occurs when growing long bone( following amputaion in children) stretches the stump tissues & skin into a unsightly cone.

36. Types: 2 types ( 1) The open amputation or guillotine amputation performed when infection is present or is likely to develop . Tissue and bone are severed at the same level, and   the wound is not closed, but left open to drain   (2) The closed amputation , or flap amputation. S kin flaps are left to cover the stump end . End bearing( SYME, Gritti -Stokes) Cone Bearing( Below/ above knee etc) Preferred method, heals faster and allows the patient to be fitted with a prosthetic device much sooner .

37. Leg amputations can be divided into 2 broad categories Minor amputations: amputation of digits partial foot amputation ( Chopart , Lisfranc, Ray) ankle disarticulation ( Syme ) Major amputations: Below-knee amputation(BKA) knee disarticulation ( Gritti or Gritti -Stokes) above-knee amputation ( transfemoral ) hip disarticulation

38. Below knee amputations Ideal length of stump: 12-14 cm from middle of knee jt.( never less than 8cm) To cover stump 2 types skin flaps commonly used: long posterior flap & skew flap( equally long flap taken, joined anteriorly 2.5cm from tibial crest ) whichever method used, total length of flap must be 1.5 times the diameter of the length at the point of bone section . Nerves are not clamped but pulled down gently & transected as high as possible . Fibula is divided 2cm proximal to the level of tibial division .

39. SURGICAL APPROACH FOR POSTERIOE FLAP FOR BELOW KNEE

40. Above knee amputations- Flaps used are equal in length Ideal length of amputation should not be less than 20-25 cm from tip of greater trochenter .

41. Arm amputations amputation of digits metacarpal amputation wrist disarticulation forearm amputation ( transradial ) elbow disarticulation above-elbow amputation ( transhumeral )

42. Optimum length in above elbow = 20cm from acromium & anything above it. Below elbow = 20 cm from tip of olecranon . 8 cm stump is minimum

43. Postoperative care of an amputee Exercise & mobilisation After surgery ,flexion deformity prevented by use of a cloth placed over the stump with sand bags on each side to weight it down . Mobility is progressively increased with walking between bars & the use of an inflatable artificial limb , which allows weight bearing to be started before a artificial limb is ready .

44. Complications Early complications— Haemorrhage Infection –abscess formation Wound dehiscence & gangrene of flaps DVT Pulmonary embolism Late complications— Pain resulting from unresolved infection(sinus , osteitis , ring sequestrum ) Bone spur scar adherent to adherent to bone Amputation neuroma . Phantom limb Phantom pain Ulceration of the stump because of pressure effects of the prosthesis .