dvt prophylaxis in surgical patients - mc.vanderbilt.edu€¢ rogers and caprini score can be used...
TRANSCRIPT
Background
• The problem: DVT and its sequelae • DVT: sequelae
– Pulmonary embolism (PE) – Post-thrombotic syndrome (PTS) – Pulmonary hypertension (PH)
• DVT, PE, and PTS are the most common preventable causes of in-hospital death
• DVT has 19% incidence in general surgery patients
Risk Factors for Venous Thromboembolism (VTE)
• Surgical patients uniformly manifest the Virchow Triad – Stasis (i.e. immobilization) – Endothelial injury (i.e. trauma, central venous
catheter placement) – Hypercoagulability (i.e. TF release, increased PAI-
1)
Additional VTE Risk Factors • Increased age • Malignancy • Immobilization • Trauma (esp. spinal cord injury) • Oral contraceptive use • Hormone replacement therapy • Pregnancy, esp. in puerperium • Neurologic disease (esp. extremity paralysis) • Inflammatory bowel disease, esp. active disease • Central venous catheter, transvenous pacemaker • May-Thurner syndrome • Paget-Schroetter syndrome • Cardiac dysfunction (maybe) • Obesity (maybe)
Hypercoagulable States • Antiphospholipid, anticardiolipin antibodies • Antithrombin III deficiency • Protein C/S deficiency • Factor V Leiden • Prothrombin gene 20210A mutation • Blood group non-O • Dysfibrinogenemia • Dysplasminogenemia • Hyperhomocystinemia • Reduced heparin cofactor II activity • Elevated levels of clotting factors (XI, IX, VII, VIII, X, II) • Elevated levels of PAI-1
Hypercoagulable States • Antiphospholipid antibodies • Antithrombin III deficiency • Protein C/S deficiency • Factor V Leiden = most common inherited thrombophilia • Prothrombin gene 20210A mutation • Blood group non-O • Dysfibrinogenemia • Dysplasminogenemia • Hyperhomocystinemia • Reduced heparin cofactor II activity • Elevated levels of clotting factors (XI, IX, VII, VIII, X, II) • Elevated levels of PAI-1
Hematologic syndromes conferring risk for VTE
• HIT • DIC • Antiphospholipid antibody syndrome • TTP • HUS • Myeloproliferative disorders
Diagnosis of DVT
• Physical exam – Pain, edema, erythema, tenderness, fever,
prominent superficial veins, Homan’s sign • Imaging
– Duplex ultrasound >> MRV, CTV >> Conventional venography
– Duplex: B-mode + spectral doppler venous incompressibility, flow abnormalities
– Duplex ultrasound is not useful for diagnosis of DVT proximal to inguinal ligament
DVT Prophylaxis
• Goals: – Prevention of venous thromboembolism (VTE) and
sequelae – Prevention of postthrombotic syndrome (PTS) – Prevention of pulmonary embolism (PE)
• Forms of DVT prophylaxis: – Pharmacologic (UFH, LMWH, ASA, warfarin,
danaparoid, fondaparinux) – Mechanical (Intermittent pneumatic compression,
graduated compression stockings, venous foot pump)
Evidence: anticoagulant thromboprophylaxis in general surgery
• Unfractionated heparin (UFH) reduces risk of fatal PE by 66%
• Low-molecular weight heparin (LMWH) reduces risk of symptomatic venous thromboembolism by 80% in patients undergoing abdominal surgery
• Prophylactic anticoagulants reduce the risk of silent DVT by 30-70%
Evidence: mechanical thromboprophylaxis
• Compared with anticoagulants and ASA, mechanical methods of thromboprophylaxis have the advantage of not increasing bleeding
• These agents are effective in reducing thrombosis compared with no prophylaxis
• However, there is no compelling data establishing the efficacy of these agents in prevention of fatal PE
• Use is indicated in low-risk surgical patients
Thromboprophylaxis in general surgery
• Risk for VTE can be predicted using validated evidence-based scoring systems
• Rogers and Caprini score can be used to estimate VTE risk
• Decision regarding method of VTE prophylaxis needs to weigh bleeding risk versus risk of VTE
• Bleeding risk is very low for general surgery patients receiving most forms of pharmacologic thromboprophylaxis (<5%)
• Healthy 25 yo male presents after driving motorcycle into fence and striking left flank on tree trunk. In addition to the pathology shown, patient has tib/fib and rib fractures
• 38 yo F with DM type II, metabolic syndrome, and morbid obesity has failed conventional weight loss programs
Pharmacologic Thromboprophylaxis: Considerations
• LMWH – More expensive – Longer half life, less
frequent dosing – Contraindicated in
renal failure – Lower risk of HIT
• UFH – Less expensive – Shorter half life – Can use in renal failure – Greater safety in pts
with epidural catheters – Higher risk of HIT
LMWH and UFH have similar efficacy in thromboprophylaxis in general surgery patients
Administration of pharmacologic thromboprophylaxis
• UFH – Initiate 1-2 hours prior to induction of general
anesthesia – TID dosing superior to BID dosing
• If pharmacologic thromboprophylaxis is indicated, continue until hospital discharge or at least 7 days postoperatively
• Certain populations require extended thromboprophylaxis for 4 weeks (i.e. major cancer surgery, SCI, history of VTE) (Grade 1B)
DVT: Treatment
• Immediate systemic anticoagulation = standard therapy – Therapeutic anticoagulation with UFH infusion or
LMWH (1 mg/kg BID) – VKA (i.e. warfarin)
• Delay in initiation of therapeutic anticoagulation >24 hrs is associated with increased rate of VTE
DVT: duration of treatment?
• 30% of patients develop recurrent DVT within 10 years of initial DVT
• Risk factors for recurrent DVT: – Older age – Obesity – Malignant neoplasm – Extremity paresis
IVC Filter Placement: Indications
• Complication of anticoagulation • Contraindication to anticoagulation (i.e.
excessive bleeding risk) • Failure of anticoagulation • Free-floating thrombus > 5 cm • High risk of PE
New trends in DVT management
• Recently there has been increased recognition of increased incidence of PTS with anticoagulation alone
• Early thrombus removal strategies have been advocated – Good functional capacity, ambulatory patients
with first episode of ileofemoral DVT <14 days and low bleeding risk (Grade 2C)
– Limb-threatening ischemia (phlegmasia cerulea dolens) (Grade 1A)