Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardiovascular system > Anticoagulants > Flashcards

Anticoagulants Flashcards

1
Q

which type of blood vessels do anticoagulants mainly work in

A

They work in slower-moving veins where a thrombus is made of fibrin, platelets + red blood cells. They are less useful in arteries because they are faster-flowing and a thrombus would be made of platelets + little fibrin

note: fibrin is a major component of a blood clot. Anticoagulants target fibrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

when should patients taking anticoagulants seek immediate medical attention

A
  • bleeding that is severe
  • bleeding that does not stop or recurs
  • who have other signs or symptoms of concern (e.g. sudden severe back pain or breathlessness)
  • patients who have sustained a head injury should be referred to the hospital emergency department
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how do vitamin k antagonists work as anticoagulants?

name some examples of vitamin-k anticoagulants

A

They inhibit the formation of the active form of vitamin K which is needed for clotting factors involved in coagulation.

examples of vitamin-K anticoagulants:

  • warfarin (drug of choice)
  • acenocoumarol
  • phenindione
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how long does it take for the full anticoagulant effect of vitamin-K antagonists to develop

A

at least 48-72 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what drug is given if a patient needs an immediate anticoagulant effect but is taking vitamin - k antagonists

A

vitamin k antagonists anticoagulant effect takes at least 48-72 hours for full effect.

Must give unfractionated or low molecular weight heparin alongside if immediate anticoagulant effect is needed,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the preferred drug for prophylaxis of venous thromboembolism in patients undergoing surgery

A

unfractionated or low weight heparin

note warfarin can be used instead for this if a patient has been taking warfarin for a long time and they’re at high risk for thromboembolism. (seek expert advice for this)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

when might warfarin be used in prophylaxis of venous thromboembolism in patients undergoing surgery

A

in selected patients that have been taking warfarin long-term and they are at risk for thromboembolism. (seek expert advice for this)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the base-line prothrombin time and when should it be taken

A

prothrombin time measures the time it takes for your blood to clot.

it should be taken before treatment (base-line) but treatment with an anticoagulant should not be delayed whilst waiting for result

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does INR mean

A

INR= international normalized ratio (INR). It is how the prothrombin time is expressed.

Prothrombin time= the time it takes for your blood to clot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

when would you deem an INR result as satisfactory

A

if it is within 0.5 units of the target value.

note larger deviations from target value than this mean the dose needs to be adjusted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the recommended time a patient should be taking warfarin for isolated calf-vein deep-vein thrombosis

A

6 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the main adverse effect of all oral anticoagulants

A

haemorrhage (bleeding)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what should you do if an anticoagulant is stopped but not reversed

A

keep monitoring patient to measure the INR every 2-3 days to make sure the INR is falling.

Investigate why INR is elevated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is NOT recommended for emergency anticoagulation reversal in patients taking warfarin

A

recombinant factor VIIa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

which patients are considered high risk of thromboembolism prior to surgery

A

Those with:

  • venous thromboembolic event within the last 3 months - - atrial fibrillation with previous stroke or transient ischaemic attack
  • mitral mechanical heart valve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

if a surgery carries a high risk of bleeding + a patient was given low weight molecular heparin. When would you consider restarting the low weight molecular heparin

A

at least 48 hours after surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when might a patient be on combined antiplatelet and anticoagulant therapy

name an example of the combined therapy

A

following an acute coronary syndrome or percutaneous coronary intervention (PCI)

e.g aspirin + warfarin, warfarin + clopidogrel, aspirin + warfarin + clopidogrel (triple therapy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which carries a higher risk of bleeding:

aspirin + warfarin or clopidogrel + warfarin

A

clopidogrel + warfarin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is a DOAC

name the 4 examples

A

direct-acting oral anticoagulant

examples: apixaban, dabigatran etexilate, rivaroxaban, edoxaban

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the mechanism of action of dabigatran etexilate as a DOAC

A

it is a reversible competitive inhibitor that inhibits thrombin (a clotting factor) from converting fibrinogen to fibrin. Fibrin molecules normally combine platelets together to form blood clots (platelets aggregation) dabigatran etexilate prevents this from happening. This is known as thrombin-induced platelet aggregation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the mechanism of action of Apixaban, edoxaban, and rivaroxaban as DOACs

A

they are reversible inhibitors of activated factor X (factor Xa) which prevents thrombin generation and thrombus development.

less/no thrombin generated = less/no fibrinogen converted to fibrin so less/no platelets combined together to form blood clots (platelet aggregation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

name some indications for the use of all DOACs: Apixaban, dabigatran etexilate, edoxaban, and rivaroxaban

A
  • prevention of stroke
  • prevent systemic embolism in patients with non-valvular atrial fibrillation
  • secondary prevention of deep-vein thrombosis and/or pulmonary embolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

which DOACs are used for prevention of venous thromboembolism after elective hip or knee replacement surgery

A

Apixaban, dabigatran etexilate, and rivaroxaban

all of them apart from edoxaban

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the use of rivaroxaban

A
  • prevention of atherothrombotic events in patients with coronary or peripheral artery disease
  • acute coronary syndrome with raised biomarkers

note this is part of secondary prevention of cardiovascular events

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What monitoring do you need for DOACs

do they need regular anticoagulation monitoring

A

monitor for signs or bleeding or anemia (stop treatment if severe bleeding occurs)

No they don’t need regular anticoagulation monitoring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how long does it take for the anticoagulant effect of DOACS to stop

what is the consequence of this

A

12-24 hours after the last dose was taken

consequence: if a patient misses or delays a dose, it can have a reduction in the anticoagulant effect

27
Q

what drug can reverse the anticoagulant effect of dabigatran etexilate

A

Idarucizumab

it can be used in life-threatening/ uncontrolled bleeding, emergency surgery/ urgent procedures

28
Q

what drug can reverse the anticoagulant effect of apixaban or rivaroxaban

A

Andexanet alfa

it can be used in life-threatening/ uncontrolled bleeding

29
Q

how do you switch a patient from warfarin to a DOAC

A
  • stop warfarin treatment before starting DOAC.

this is to reduce risk of over-anticoagulation + risk of bleeding

30
Q

when should a woman postpartum start taking warfarin again

A

delay warfarin until risk of bleeding is low (usually 5-7 days after birth delivery)

31
Q

what does it mean if your INR is too high (higher than target INR)

A

if the INR is too high, it means your blood is taking longer to clot so you are at increased risk of bleeding

32
Q

what does it mean if your INR is too low (lower than target INR)

A

if the INR is too low, it means your blood is clotting quicker so you are at increased risk of a blood clot

33
Q

why should pregnant women avoid taking vitamin k antagonists in their first + third trimester

A

because all vitamin k antagonists are teratogenic. highest risk is in the 1st + 3rd trimester

34
Q

when is it advised that pregnant women stop taking vitamin k antagonists

A

stop vitamin k antagonists before the 6th week of gestation to avoid fetal abnormalities

35
Q

how often should patients on vitamin k antagonists have their INR monitoring

A
  • baseline prothrombin time taken
36
Q

name the contraindications for all DOACs

A
  • antiphospholipid syndrome
  • a lesion or condition if it is considered a risk factor to major bleeding
  • concomitant use with any other anticoagulant
  • previous stroke/ TIA (when indication is for prophylaxis of atherothrombotic events)
37
Q

can you take any other anticoagulant when taking a DOAC

A

No, must not use any other anticoagulants when taking a DOAC unless you are switching therapy when unfractionated heparin is given

38
Q

TRUE OR FALSE

Rivaroxaban should not be used in patients with prosthetic heart valves, including patients who have undergone transcatheter aortic valve replacement (TAVR)

A

TRUE

this is because there is an increased risk of all-cause death and bleeding

39
Q

which has an increased risk of recurrent thrombotic events in patients with antiphospholipid syndrome:

  • vitamin k antagonists
  • DOACs
A

DOACs

DOACs are not recommended in patients with antiphosholipid syndrome. If a patient is on a DOAC with antiphospholipid syndrome, consider switching them to a vitamin K antagonist

40
Q

why should you take rivaroxaban with food

A

because taking rivaroxaban with food increases the efficacy compared to taking it on an empty stomach

note in those who have difficulty swallowing, can crush tablets mixed with water/apple puree then eat food immediately after

41
Q

can you use DOACs whilst pregnant or breastfeeding

A

no, manufacturer advises to avoid in pregnancy (toxicity seen in animals) + breastfeeding (present in breast milk)

42
Q

what is the difference between standard/unfractionated heparin vs low molecular weight heparins

A

standard/unfractionated heparin initiates anticoagulation rapidly but has a short duration of action whereas
low molecular weight heparin has a longer duration of action

note low weight heparin is generally preferred

43
Q

although low weight heparin is usually preferred to unfractionated/standard heparin, why might unfractionated/standard heparin still be used

A

because the anticoagulant effect of unfractionated/standard heparin can quickly be stopped by stopping the infusion (due to short duration of action*

note low weight heparin has a longer duration of action

44
Q

name some examples of low weight heparins

they end in “rin”

A
  • enoxaparin sodium
  • dalteparin sodium
  • tinzaparin sodium
45
Q

what low weight heparins used for

A
  • preventing venous thromboembolism (VTE)

- treating deep vein thrombosis (DVT) and pulmonary embolism

46
Q

which type of heparin has a lower risk of causing heparin-induced thrombocytopenia

A

low weight heparins

47
Q

name some examples of parenteral anticoagulants

A
  • low weight heparin + unfractionated/standard heparin
  • Bivalirudin (used in NSTEMI or unstable angina patients as an anticoagulant for percutaneous coronary intervention)
  • Epoprostenol (prostacyclin). Also a potent vasodilator used in primary pulmonary hypertension resistant to other treatment
  • Danaparoid sodium
  • Argatroban
  • Fondaparinux
48
Q

what is Venous thromboembolism (VTE)

A

includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE), and refers to a blood clot that forms in a vein which partially or completely obstructs blood flow

49
Q

what is Hospital-acquired venous thromboembolism (VTE)

A

VTE that happens within 90 days of hospital admission

50
Q

name some risk factors for Venous thromboembolism (VTE)

A
  • surgery/trauma
  • significant immobility
  • obesity
  • pregnancy and the postpartum period
  • hormonal therapy (combined hormonal contraception or hormone replacement therapy)
  • acquired or inherited hypercoagulable states (blood which has increased tendency to clot)
51
Q

where does deep vein thrombosis (DVT) normally occur

what are the symptoms

A

DVT normally occurs in deep veins of legs or pelvis but may affect other sites. It is the most common type of VTE

symptoms:

  • localised pain/ tenderness
  • swelling
  • skin changes
  • vein distension (bulging)
52
Q

how does a pulmonary embolism (PE) normally occur

what are the symptoms

A

pulmonary embolism (PE) usually happens when a thrombus from DVT travels in the blood (embolus) and obstructs blood flow in the lungs. This causes respiratory dysfunction

symptoms:

  • chest pain
  • shortness of breath
  • haemoptysis (coughing up blood)
53
Q

TRUE OR FALSE

all patients should be assessed on their risk of venous thromboembolism (VTE) and bleeding on admission to hospital

A

True

54
Q

describe the two methods of venous thromboembolism prophylaxis

A
  • Mechanical: patients given anti-embolism stockings which provide a graduated pressure of 14-15 mmhg. They are worn day + night until patient is sufficiently mobile. or intermittent pneumatic compression device
  • pharmacological: started at soon as possible or within 24hrs of admission. patients taking anticoagulants should only receive pharmacological treatment if anticoagulant therapy has been interrupted e.g for surgery.
55
Q

which type of anesthesia (regional or general) should be used to reduce risk of VTE in patients

A

regional anaesthesia over general anaesthesia should be used if possible

56
Q

which drug can be used all types of general and orthopaedic surgery as prophylaxis to prevent VTE

A

low molecular weight heparin

57
Q

which drug is preferred as prophylaxis to prevent VTE in patients with renal impairment

A

unfractionated/ standard heparin preferred but can also use low weight molecular heparin

58
Q

what is the first line treatment option to prevent VTE in medical patients (not at hospital for surgery)

A

first line is pharmacological treatment:

- low weight molecular heparin first line (fondaparinux sodium as an alternative), for a minimum of 7 days

59
Q

which patients should NOT have mechanical treatment to prevent VTE

A
  • acute stroke or those with conditions such as:
  • peripheral arterial disease
  • peripheral neuropathy
  • severe leg oedema
  • or local conditions (e.g. gangrene, dermatitis)
60
Q

what are the 3 main drugs used in pharmacological prophylaxis of VTE in surgical patients

A
  • low weight molecular heparin
  • unfractionated/standard heparin
  • Fondaparinux sodium

note patients may also be taking anticoagulants if undergoing elective hip/knee surgery

61
Q

which drug is used for thromboprophylaxis in pregnancy

A

low weight molecular heparin

  • elastic graduated compression stocking should be applied on the affected leg as an additional treatment to manage symptoms such as pain and swelling
  • note this includes all pregnant women (who are not in active labour), or women who have given birth, had a miscarriage or termination of pregnancy during the past 6 weeks, with a risk of VTE that outweighs the risk of bleeding*
62
Q

what are the drug treatment options for patients with confirmed DVT or pulmonary embolism

A
  • first line= apixaban or rivaroxaban.

if not tolerated:

  • low molecular weight heparin (LMWH) for at least 5 days followed by dabigatran etexilate or edoxaban; or
  • LMWH + vitamin K antagonist for at least 5 days or until the INR is at least 2.0 for 2 consecutive readings, followed by a vitamin K antagonist on its own.
63
Q

how do you reverse the anticoagulant effects of low molecular weight heparin or unfractionated heparin

A
  • usually stopping the low weight heparin or unfractionated heparin is enough to reverse effects. If you need rapid reversal, use protamine sulfate (the antidote)

Cardiovascular system (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions