Anticoagulation Flashcards

1
Q

Anticoagulation recommended…

A

in addition to antiplatelet therapy to improve vessel patency and prevent re-occlusion

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2
Q

Unfractionated Heparin (UFH)

A
  • Anti-Xa and anti-IIa activity
  • Risk of heparin induced thrombocytopenia (HIT):
  • Drop in platelet count AND increased thrombosis
  • Caused by formation of antibodies that activate platelets
  • If suspecte –> Calculate 4T Score (What are the 4 T’s?)
  • Screening tests available if HIT suspected: Enzyme-linked immunosorbent assay (ELISA)- quick, high false positive rate; Serotonin release assay (SRA)- gold standard for diagnosis, often a “send-out” lab
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3
Q

Is unfractionated heparin the only anticoagulant that can cause HIT?

A

no, LMWH can also cause HIT, but there is a lower risk

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4
Q

Can a patient with a history of HIT be re- challenged with unfractionated heparin or LMWH?

A

no, pts should not be rechallenged with either

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5
Q

Unfractionated Heparin (UFH) half life

A
  • Quick onset and short half life
  • Administered as a continuous infusion
  • Dosing of UFH is based on the activated partial thromboplastin time (aPTT) or activated clotting time (ACT)
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6
Q

Enoxaparin

A
  • Low molecular weight heparin (LMWH)
  • Anti-Xa and anti-IIa activity: Higher ratio of anti-Xa/anti-IIa than UFH
  • Eliminated by kidneys: Accumulates in renal impairment
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7
Q

Do we routinely check anti-Xa levels for patients on enoxaparin?

A

no, usually not necessary and difficult to interpret the results; consider in certain cases, - very high or low body weight, renal impairment, development/worsening clot

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8
Q

Bivalirudin

A
  • Direct thrombin inhibitor
  • Not used together with GPIIb/IIIa inhibitors (except ”bail
    out”)
  • Conflicting results vs unfractionated heparin: Many studies used GPIIb/IIIa inhibitors with heparin - Difficult to determine if differences were due to
    bivalirudin vs heparin; May not be as effective for MACE and stent thrombosis - HEAT-PPCI trial; May have lower bleeding risk - BRIGHT trial and MATRIX trial
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9
Q

Fondaparinox

A
  • Factor Xa inhibitor
  • Not commonly used: Can use in patients with a history of HIT
  • Do not use alone for PCI: High rates of thrombosis; Not drug of choice if planning PCI; If already giving fondaparinux and patient needs PCI, need to give unfractionated heparin or bivalirudin also
  • Contraindicated for CrCl < 30mL/min
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10
Q

Unfractionated heparin use in UA/NSTEMI and STEMI

A

UA/NSTEMI: ischemia guided strategy - yes (48 hrs); early invasive strategy - yes (until PCI)
STEMI: fibrinolytic - yes (48 hrs); PCI - yes (until PCI)

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11
Q

Bivalirudin use in UA/NSTEMI and STEMI

A

US/NSTEMI: ischemia guided strategy - no; early invasive strategy - yes (until PCI)
STEMI: fibrinolytic - no, consider using for HIT; PCI - yes (until PCI, preferred in high bleeding risk)

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12
Q

Enoxaparin use in UA/NSTEMI and STEMI

A

UA/NSTEMI: ischemia guided strategy - yes (duration of hospital stay up to 8 days); early invasive strategy - yes (until PCI)
STEMI: fibrinolytic - yes (duration of hospital stay up to 8 days); PCI - no

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13
Q

Fondaparinux use in UA/NSTEMI and STEMI

A

UA/NSTEMI: ischemia guided strategy - yes (duration of hospital stay up to 8 days); early invasive strategy - not ideal, do not use alone for PCI
STEMI: fibrinolytic - yes (duration of hospital stay up to 8 days); PCI - no

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