Antiplatelet, Antithrombotic, and Thrombolytic Agents Flashcards
What is protamine currently synthesized from?
Biotechnology
Protamine was originally produced from fish products.
Who should avoid protamine?
Patients with a strong fish allergy and those taking NPH insulin
Due to increased risk of a histamine-mediated reaction.
What is the effect of high doses of protamine?
Can act as an anticoagulant
For usual doses, this effect is weak.
What do prasugrel and clopidogrel require for activation?
Hepatic cytochromes
Both drugs require oxidation to generate their active drug metabolite.
How many oxidative steps does prasugrel require for activation?
One oxidative step involving CYP2C19
How many oxidative steps does clopidogrel require for activation?
Two oxidative steps
What is a primary contraindication for thrombolytic therapy?
Lifethreatening bleeding such as intracranial hemorrhage
Is a history of ischemic stroke a contraindication for thrombolysis in STEMI?
No, unless the stroke occurred in the last 3 months
What is one major risk associated with premature discontinuation of antiplatelet therapy?
Increased risk for stent thrombosis
Hazard ratio of 90 for stent thrombosis was found in one large-scale registry.
What is the recommended duration of dual antiplatelet therapy (DAPT) after first-generation DES?
12 months
What is bivalirudin characterized as?
A short amino acid sequence with the shortest half-life among IV direct thrombin inhibitors
What is a notable characteristic of cangrelor in relation to clopidogrel?
Reduces the odds of MACE by 19% with no difference in GUSTO severe bleeding
What are some factors released from platelets?
ADP, fibrinogen, sCD40L
These factors either accelerate coagulation or promote inflammation.
What distinguishes ticagrelor from other oral antiplatelet agents?
It is the first orally available P2Y12 receptor antagonist that reversibly affects the receptor
What is the risk of major bleeding for a non-ACS catheterization and possible PCI?
<1%
Which access method has shown lower rates of major bleeding?
Radial access compared to femoral access
What has contributed to the decrease in major bleeding rates in recent years?
Changes in practice despite the use of multiple antiplatelets and anticoagulants
What factors are important when assessing anticoagulation with enoxaparin?
Dose given, hours since dose, renal function
Creatinine clearance influences the anticoagulant effect.
What is the mechanism of heparin-induced thrombocytopenia (HIT)?
Antibody generation in response to a heparin–platelet factor complex
What is the main activity of thrombin?
Facilitating the conversion of fibrinogen to fibrin
What role does argatroban play in anticoagulation?
Hepatically metabolized
What is the primary risk associated with NSTEMI-ACS patients receiving fibrinolytic therapy?
Higher rate of MI
What is cangrelor’s classification?
Modified ATP derivative, irreversibly inhibits the ADP receptor of platelets
What is the effect of abciximab on platelet receptors?
Avidly binds to platelet receptors
What is the significance of the TRITON trial results?
Prasugrel decreased composite ischemic endpoint but increased major bleeding rate
What is the effect of idarucizumab and andexanet?
Effectively reverse the effects of anti-IIa and anti-Xa oral agents
What is a notable characteristic of eptifibatide?
Given in excess of platelet receptors, making platelet transfusions ineffective
What does the DANISH Health System track?
Prescriptions and hospitalizations related to bleeding
What is the effect of adexanet and protamine on LMWHs?
They will partially reverse the effects of LMWHs
Adexanet is used for reversing the effects of certain anticoagulants, while protamine is primarily used for reversing heparin.
Why are platelet transfusions not helpful for eptifibatide?
Eptifibatide is given in a several hundred-fold excess of platelet receptors due to its pharmacokinetics and pharmacodynamics
This means that the drug binds to the receptors extensively, rendering transfusions ineffective.
What hazard ratio was observed for bleeding-related hospitalizations among those receiving triple therapy in the DANISH Health System?
1.41
This indicates a significant increase in the risk of bleeding-related hospitalizations.
What was the percentage increase in BARC ≥ 2 bleeding from the ISAR TRIPLE trial when comparing 6 weeks vs. 6 months of clopidogrel?
From 7.6% to 12.2%
This represents approximately a 60% increase in bleeding events with the extended duration.
In the WOEST trial, what was the bleeding occurrence rate at 1-year follow-up for the triple therapy group?
44.4%
Compared to 19.4% for the double therapy group, indicating more than twice as often bleeding in the triple therapy group.
What did the DAPT study show regarding major adverse cardiac and cerebrovascular events (MACCE) with prolonged antiplatelet therapy?
Reduced from 9% to 4.3% (p < 0.001)
This demonstrates the antithrombotic benefit of prolonged therapy.
What was the increase in GUSTO moderate or severe bleeding with prolonged DAPT?
From 1.6% to 2.5% (p = 0.001)
This highlights the trade-off between benefits and risks in prolonged antiplatelet therapy.
What is the recommended therapy for patients at high risk of postprocedure bleeding with oral anticoagulation?
Perioperative UFH therapy
This is particularly for patients with mechanical valves or recent thrombosis.
What should be done if a patient’s INR remains elevated after discontinuing warfarin?
Consider using a particularly small arterial sheath (5-Fr) in the radial artery
This is to manage the risk of bleeding during procedures.
Fill in the blank: The occurrence of stent thrombosis and MI was increased in the first ______ months after stopping clopidogrel.
3
This emphasizes the critical period post-antiplatelet therapy.
True or False: The patient’s stent placement was done recently, raising concerns for stent thrombosis.
False
The stent placement was done many years before, alleviating concerns.
