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115 Cards in this Set
- Front
- Back
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What is DVT?
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a thrombus composed of cellular material (red and white blood cells, platelets) bound together with fibrin strands
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What 3 primary components (Virchow's triad) plays a role in development of thrombus?
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venous stasis, vascular injury, hypercoagulability
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What is venous stasis?
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slowed blood flow in the deep veins of the legs from damage of venous valves, vessel obstruction, prolonged periods of immobility, or increased blood viscosity
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What conditions associated with venous stasis?
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HF, MI, surgery, paralysis
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What can cause hypercoagulable states?
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malignancy, activated protein C resistance, deficiency of protein C protein S or antithrombin, factor VIII or XI excess, antiphospholipid antibodies
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Where do most thrombi begin?
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lower extremities
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What are symptoms of DVT?
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unilateral leg swelling, pain, tenderness, erythema, and warmth
palpable cord and a positive Homans' sign |
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What is postthrombotic syndrome?
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a long term complication of DVT caused by damage to venous valves
may produce chronic lower extremity swelling, pain, tenderness, skin discoloration, and ulceration |
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What are symptoms of PE?
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dyspnea, tachypnea, pleuritic chest pain, tachycardia, palpitations, cough, diaphoresis, hemoptysis
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What are risk factors for DVT?
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increased age, major surgery, previous VTE, trauma, malignancy, hypercoagulable state, drug therapy
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What are the most accurate and reliable method for diagnosis of VTE?
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radiographic contrast studies
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What are used for initial evaluation if contrast studies arent?
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ultrasonography, CT, ventilation-perfusion scan
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What lab value may indicate VTE?
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elevated D-dimer, sensitive marker of clot formation but may be caused by other conditions (surgery, trauma, pregnancy, cancer)
negative test excludes VTE, but positive cant confirm it |
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What does a D-dimer test test?
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degradation product of fibrin blood clots
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What is the goal for VTE tx?
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prevent development of PE and postthrombotic syndrome, reduce morbidity and mortality from acute event, minimize AE and cost
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What is initial tx for DVT?
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LMWH, fondaparinux, UFH
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Which initial tx is preferred?
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LMWH and fonaparinux
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What is preferred DVT tx in cancer pt?
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LMWH
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What should also be started when LMWH, fondaparinux, UFH is started?
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warfarin
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When can UFH, LMWH, or fandaparinux be stopped?
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at least 5 days warfarin tx and when INR > 2
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What is target INR when taking warfarin?
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2-3
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How long should oral anticoagulation therapy be continued?
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at least 3 months
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What is used if oral anticoagulation is CI (pregnancy)?
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LMWH or UFH
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What pts have indefinite oral anticoagulation tx?
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idiopathic VTE, inherited disorder of hypercoagulability, or antiphospholipid antibodies
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What pts should have oral anticoagulation tx at least 12 months?
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pt with continuing risk factors (malignancy, immobility)
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What is MW of UFH?
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15,000 daltons
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How does UFH cause anticoagulant effect?
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specific pentasaccharide sequence on heparin molecule binds to antithrombin and causes antithrombin to have 100-1000 time more potent anticoagulant effect
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What factors does antithrombin inhibit?
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IXa, Xa, XIIa, and thrombin (IIa)
inhibits thrombin induced activation of factors V and VIII |
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How does UFH work?
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prevents growth and propagation of formed thrombus and pts trombolytic system degrades clot
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What are CI to UFH?
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active bleeding, hemophilia, severe liver disease with elevated PT, severe thrombocytopenia, malignant HTN, inability to monitor tx
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What route is UFH given?
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parenterally, preferably IV or SQ, IM is discouraged and causes erratic absorption and may cause hematomas
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If rapid anticoagulation is required when using UFH, how is it given?
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wt based IV bolus followed by continuous IV infusion
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What should be monitored at initiation of therapy and within 6 hours after beginning infusion or dose change?
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aPTT(activated partial thromboplastin time)
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What is therapeutic range for aPTT?
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1.5-2.5x mean normal value
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What is primary AE with UFH?
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bleeding
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What are symptoms of bleeding?
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HA, joint pain, chest pain, abdominal pain, swelling, tarry stools, hematuria, passing of bright red blood through rectum
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What can be given to reverse UFH if bleed occurs? What dose?
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protamine sulfate, 1mg/100units of UFH during previous 4hrs, 50 mg max
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Is heparin associated thrombocytopenia or heparin induced thrombocytopenia more serious?
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heparin induced thrombocytopenia
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What is thrombocytopenia?
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platelet count < 150,000
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What is HAT?
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benign, transient, and mild, usually occurs in first few days of tx, plt count rarely below 100,000, no need to change therapy
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What is HIT?
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serious immune mediated problem. Plt drops by more than 50% from baseline. Plt fall after 5-10 days of UFH therapy.
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What might indicated HIT?
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pt develops thromboembolic event (DVT, PE, stroke, MI, limb artery occlusion) during or soon after UFH.
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What is tx for HIT?
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all sources of heparin d/c and alternative anticoagulant (direct thrombin inhibitor) started
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Which drugs are FDA approved for use in HIT?
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lepirudin and argatroban
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What are effects of long term use of UFH?
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alopecia, priapism, hyperkalemia, osteoporosis
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What are LMWH?
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fragments of UFH that are heterogenous mixtures of sulfated glycosaminoglycans
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How does MW of LWMH compare to UFH?
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1/3
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What is advantage of LMWH over UFH?
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more predictable anticoagulation, improved SC bioavailability, dose independent clearance, longer t1/2, lower incidence of thrombocytopenia, less lab monitoring
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What is MOA of LMWH?
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like UFH, accelerate activity of antithrombin and prevent growth and propagation of formed thrombi
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When is peak anticoagulant effect from LMWH seen?
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3-5hrs after SC dose
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What is dose for enoxaparin (Lovenox)?
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1mg/kg Q12 or 1.5mg/kg Q24
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What is dose for dalteparin (Fragmin)?
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100units/kg Q12 or 200 units/kg Q24
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What is dose for tinzaparin (Innohep)?
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175 units/kg Q24
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What labs at baseline for LMWH?
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Pt/INR ratio, aPTT, CBC w/ plt, Cr
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What is measuring antifactor Xa activity helpful?
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significant renal impairment, weigh less than 50kg, obese, more than 14 day therapy, pregnant, high risk for bleeding
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What is sample for antifactor Xa taken?
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4 hrs after second or third SC injection
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What is target for antifactor Xa?
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0.5-1
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What is most common AE from LMWH?
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bleeding, less common that UFH
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What is tx for bleeding from LMWH?
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protamine sulfate (doesnt neutralize anticoagulant effect completely)
1mg/1mg enoxaparin, 1mg/100units dalteparin or tinzaparin in previous 8 hrs if given 8-12hrs dose 0.5mg/100 units if given mor than 12hrs earlier, dont us protamine |
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What is MOA of fondaparinux (Arixtra)?
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selective inhibitor of factor Xa, it binds to antithrombin accelerating its activity (no effect on thrombin at therapeutic concentrations)
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What is fondaparinux (Arixtra) approved for?
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prevention of VTE in pts undergoing orthopedic (hip fracture, hip and knee replacemen) surgery and tx of VTE and PE
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What is fondaparinux dose for VTE prevention?
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2.5mg SC daily 6-8hrs after surgery
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What is fondaparinux dose for tx of DVT and PE?
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7.5mg SC daily
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Do pts on fondaparinux require routine coagulation testing?
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no
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Do DTI require anti-thrombin to have antithrombotic activity?
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no, directly interact with thrombin
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What advantage do DTI have over UFH and LMWH?
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capable of inhibiting circulating and clot bound thrombin
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Do DTIs induce thrombocytopenia?
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no, used for tx HIT
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Lepirudin
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refludan, DTI
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How many times can pt be treated with lepirudin?
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once, pt may develop antibodies which cause anaphylaxis if take another tx
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What is lepirudin indicated for?
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anticoagulation in pt with HIT and associated thrombosis
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How many days is lepirudin given?
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2-10, or longer if needed
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What lab is monitored when on lepirudin?
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aPTT
baseline, 4hrs after start infusion, daily |
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What is goal aPTT for lepirudin?
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1.5-2.5x control
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Is lepirudin renal dosed?
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yes
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bivalirudin
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angiomax, DTI
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What is bivalirudin indicated for?
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anticoagulant in unstable angina undergoing percutaneous transluminal coronary angioplasty
with provisional use of glycoprotein IIb/IIIa inhibitor for use as anticoagulant in pt undergoing PCI pt with (or risk of) HIT undergoing PCI |
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What is argatroban indicated for?
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prevention or tx of thrombosis in HIT
anticoagulant in pt with HIT, risk of HIT, or undergoing PCI |
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When should aPTT be obtained when taking argatroban?
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2hrs after initiation
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What is goal aPTT for argatroban?
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1.5-3x control
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desirudin
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Iprivask
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What is desirudin indicated for?
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prevention of DVT in pt undergoing elective hip replacement surgery
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When is desirudin dose started?
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5-15minutes before surgery, Q12h x 12 days
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What is most common AE for DTI?
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hemorrhage
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Are there any agents that reverse DTIs?
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no
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What is MOA of warfarin?
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vitamin K antagonist
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What factors does warfarin decrease?
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II(prothrombin), VII, IX, X, protein C and S
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Does warfarin have any effect on previously circulating clotting factors or previously formed thrombi?
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no
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How long for warfarin to have full antithrombotic effect?
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8-15 days
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When giving heparin and warfarin, when can you d/c heparin?
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INR is in desired range for 2 consecutive days
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What is usual initial dose of warfarin?
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5-10mg
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What is target INR when taking warfarin?
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2-3
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How often should INR be measured?
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after thromboembolic event every 3 days during 1st week, once dose response established every 7-14 days, when INR stabilizes every 4 weeks
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How long for anticoagulaiton if thrombotic event associated with major transient or reversible factor (hospitalization)?
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3 months
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How long for anticoagulation if VTE associated with minor or transient or reversible factor (estrogen therapy)?
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3 months, 6 months prefered
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How long for anticoagulation for unprovoked (idiopathic) VTE?
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at least 6-12 months, indefinite if possible
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How long for anticoagulation for recurrent VTE?
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indefinite or lifelong
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What is most frequent site of bleeding when taking warfarin?
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GI tract
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What is most serious complication from warfarin?
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intracranial hemorrhage
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What is used if rapid reduction in INR is needed?
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vitamin K1 (phytonadione)
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What INR is vitamin K1 used?
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may be used if 5-9, recommended if INR greater than 9
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What other AE form warfarin?
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purple toe syndrome and skin necrosis
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What are CI for warfarin?
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active bleeding, hemorrhagic tendencies, pregnancy, history of warfarin induced skin necrosis
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When should warfarin be used cautiously?
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history of GI bleeding, recent neurosurgery, alcoholic liver disease, severe renal impairment, inability to keep follow-up appointments
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What is action of thrombolytic agents?
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enhance conversion of plasminogen to plasmin, which subsequently degrades the fibrin matrix
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What is AE for thromolytics?
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substantial risk of hemorrhage
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When should thrombolytics be used?
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shock, hypotension, right ventricular strain, or massive DVT with limb gangrene
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Streptase
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streptokinase
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Abbokinase
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urokinase
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Activase
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alteplase
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Is UFH used with thrombolytic therapy?
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no
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When should UFH be used after using thrombolytics?
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if aPTT <2.5x control
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What nonpharm for VTE prevention?
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early ambulation, electrical stimulation of calf muscles during prolonged surgery, graduated compression stockings, intermittent pneumatic compression devices, inferior vena cava filters
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Do LMWHs, fandaparinus, or low dose UFH provide more protection?
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LMWHs and fondaparinux provide superior protection against VTE
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Is one LMWH superior to another for prevention VTE?
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no
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How long antithrombotic therapy after hip replacement?
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21-35 days
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