Anticoags Flashcards
(98 cards)
1
Q
heparin binds to what enhancing the formation of what complex?
A
antithrombin; thrombin-antithrombin complex
2
Q
by how many range of times does heparin enhance thrombin-antithrombin complex formation?
A
1,000-10,000
3
Q
antithrombin not only binds to thrombin (factor IIa), but also what other 4 factors?
A
IX, Xa, XI, XII
4
Q
by binding to these factors, what does antithrombin do to them?
A
removes them from circulation
5
Q
heparin also inhibits the function of what?
A
platelets
6
Q
in one word, what is the IV onset of heparin?
A
immediate
7
Q
what is the range of hours onset of subcutaneous heparin?
A
1-2 hours
8
Q
Is heparin highly charged or highly uncharged and acidic or basic?
A
highly charged acidic molecule
9
Q
is heparin highly or poorly lipid soluble?
A
poorly
10
Q
since heparin is poorly lipid soluble, is it poorly or highly absorbed in the GI tract?
A
poorly
11
Q
IM heparin is avoided d/t the possible formation of what?
A
hematoma formation
12
Q
does heparin have a high or low molecular weight?
A
high
13
Q
does heparins elimination half life increase or decrease with body temp below 37 degrees celsius?
A
decrease
14
Q
heparin elimination is prolonged in what 2 organ dysfunctions?
A
liver, kidneys
15
Q
is the dose response relationship of heparin linear?
A
no
16
Q
does the anticoag response to heparin increase proportionately or disproportionately in intensity and DOA as dose increases?
A
disproportionately
17
Q
what are the 4 reasons for the disproportionate anticoag responses to heparin? (TNOA, T, HCNOHWCPB, VOAR)
A
the need of antithrombin, temperature, highly charged nature of heparin which causes protein binding, variability of anticoag reponses
18
Q
dose response example of heparin:
- 100 units/kg IV = what elimination half life in minutes?
- 400 units/kg IV = what elimination half life in minutes?
A
- 56 minutes
2. 152 minutes
19
Q
Heparin is ued to prevent and treat what 3 things? (VS, PE, ACS)
A
venous thrombosis, PE, acute coronary syndrome
20
Q
heparin is also used for what 2 siutations? (ECC, H)
A
extracorporeal circulation, HD
21
Q
IV heparin needs to be discontinued within what hour range before surgery?
A
4-6 hours
22
Q
what are the 2 types of heparin induced thrombocytopenia? (M, S)
A
mild, severe
23
Q
Mild HITT:
- occurs what % range of the time?
- plts are less than how many?
- d/t what induced plt aggregation?
- seen between hours to what day range after initial dose?
A
- 30-40%
- <100,000
- drug induced
- 3-15 days
24
Q
Severe HITT:
- occurs what % range of the time?
- plts are less than how many?
- resistant to effects of what drug?
- seen what range of days after heparin administration?
- can thrombotic events occur?
- d/t the formation of heparin dependent antiplatelet whats?
- what should be discontinued immediately?
A
- 0.5-6%
- <50,000
- heparin
- 6-10 days
- yes
- antibodies
- heparin
25
what is the most common AE of heparin?
hemorrhage
26
what are the 3 coag evals for heparin?
aPTT, Anti-Xa heparin assay, activated clotting time
27
for heparin treatment we want the aPTT to be what range of times larger than the predrug value?
1.5-2.5 times larger
28
what is the usual aPTT predrug value in range of seconds?
30-35 seconds
29
why have some labs switched to anti-Xa heparin assay with low dose heparin regimens instead of aPTT?
aPTT has variable responses
30
Activated clotting time (ACT):
1. used for lower or higher doses of heparin?
2. used for heparin > how many units per mL?
3. used for what 2 procedures? (CB, CCL)
4. best if measured at what 2 instances and every how many minutes thereafter?
5. what is the target seconds range?
1. higher
2. > 1 units/mL
3. cardiopulmonary bypass, cardiac cath lab
4. pre-heparin, 3-5 minutes after; every 30 minutes thereafter
5. 350-400 seconds
31
what are the 5 things that affect ACT? (H, H, T, CAI, CD)
hypothermia, hemodilution, thrombocytopenia, contact activation inhibitors (aprotinin), coagulation deficiencies
32
what drug is used to reverse heparin?
protamine
33
what does protamine work?
it's positively charged alkaline so it combines with the negatively charged acidic heparin yielding a stable complex devoid of anticoag activity
34
how many mg of protamine for every 100 units of circulating heparin?
1 mg
35
why do ppl overdose protamine?
because they dose it based on the initial heparin given
36
protamine:
1. what is its clearance in minutes?
2. is clearance more or less rapid than heparin's?
3. what is heparin's half life? (hours)
4. may see heparin rebound which will require a smaller dose of what?
1. 20 minutes
2. more rapid
3. 1 hour
4. protamine
37
Protamine:
1. what are two AEs?
2. release of what causes hypotension?
3. allergic reactions most often occur in pts who had this procedure and who are on what insulin?
1. hypotension, pulm HTN
2. histamine
3. vasectomy, NPH
38
LMWH:
1. what are the 2 uses? (T, ACS)
2. stop at least how many hours before surgery and even longer in pts with what dysfunction?
3. does protamine neutralize?
4. increase chance of hematomas in what 2 areas with LMWH?
5. how should you hold LMWH before doing a spinal or epidural block?
1. thromboprophylaxis, acute coronary syndrome
2. 12 hours, renal dysfunction
3. no
4. spinal, epidural
5. 24 hours
39
LMWH:
1. what are the 3 drugs? (F, E, D)
2. what 2 are derived from UFH?
3. which one is synthetic?
4. Both heparin derivatives are more consistent between pts than heparin because they bind less avidly to what?
5. in what pt population is LMWH's effect so prolonged that UFH should be used?
1. fondaparinux, enoxaparin, dalteparin
2. enoxaparin, dalteparin
3. fondaparinux
4. protein
5. renal failure
40
Fondaparinux:
1. what factor does it inhibit?
2. does it have activity against thrombin?
3. it is used as an alternative in pts with what?
4. what coag eval is used?
5. what is elimination half life in hours?
6. because of half life, how often is it given a day?
7. should not be used in what pts?
1. Xa
2. no
3. HIT
4. anti-Xa heparin assay
5. 15 hours
6. once per day
7. renal failure
41
direct thrombin inhibitors:
1. what are the 5 meds? (BALDD)
2. which one is the oral agent?
3. which one is commonly used for cardiac interventional procedures?
4. primarily used for pts at increased risk for what two things? (H, HR)
5. they are acceptable alternative in anticoagulation for what procedure?
6. Which one is given SC?
7. which one binds to thrombin irreversibly?
8. which one is eliminated via the liver?
1. bivalirudin
2. dabigatran
3. bivalirudin
4. HIT, heparin resistance
5. CPB
6. Desirudin
7. lepirudin
8. argatroban
42
Bivalirudin:
1. what are the 2 uses?
2. what administration route?
3. what is half life? (minutes)
4. what lab is monitored?
1. interventional cardiac procedures, HITT pts
2. IV
3. 25 minutes
4. ACT
43
Argatroban:
1. What are the 3 uses? (pts at risk for what?, prophylaxis and treatment for what?, pts undergoing what procedure?)
2. what administration route?
3. what is half-life? (minute, range)
4. anticoagulation is normal after how many hours?
5. elimination via what?
6. use what 2 test to monitor?
1. HIT, thrombus, percutaneous coronary intervention (PCI)
2. IV
3. 40-50 minutes
4. 4 hours
5. liver
6. aPTT, ACT
44
Lepirudin:
1. what are the 2 uses? (pts with what, for prevention of what?)
2. what administration route?
3. elimination via what?
4. monitor what lab value?
5. does it inhibit thrombin reversibly or irreversibly?
1. HIT, VTE
2. IV
3. kidneys
4. aPTT
5. irreversibly
45
Desirudin:
1. what are the 2 uses? (pts with what, prevent clots after what 2 procedures)
2. what administration route?
3. eliminated via what?
4. monitor what lab?
1. HIT, total knee or hip arthroplasty
2. SC
3. Kidneys
4. aPTT
46
Dabigatran:
1. What are the 4 uses? (prevent what 2 things, what rhythm, after what 2 procedures)
2. eliminated via what route?
3. monitor what 2 lab values?
1. stroke prevention, VTE prevention, a fib, total hip or knee arthroplasty
2. kidneys
3. aPTT, thrombin times
47
Stop lepirudin and desirudin how many hours before surgery?
24 hours
48
stop dabigatran how many hours before surgery in pts with normal renal function and how many hours (range) before surgery in pts with renal dysfunction?
48 hours; 72-96 hours
49
Warfarin:
1. what are the 3 reasons why it is the most frequently used PO anticoag? (predictable what 2 things with excellent what?)
2. what is usual PO dose range? (mg)
3. what enzyme does it inhibit?
4. what 4 factors are inhibited by warfarin?
5. what is the hour range of peak effect?
6. treatment of VTE and stroke in pts with what 2 conditions?
7. what is the onset hour range?
1. onset, DOA; bioavailability
2. 5-10 mg
3. vitamin k reductase
4. II (thrombin), VII, IX, X
5. 36-72 hours
6. a fib/flutter, prosthetic heart valve
7. 8-12 hours
50
Warfarin:
1. rapidly or slowly absorbed?
2. what % is albumin bound making renal excretion negligible?
3. what is elimination half life hour range?
4. excreted in what two places?
1. rapidly
2. 97%
3. 24-36 hours
4. bile, urine
51
what are the 4 disadvantages of warfarin? (DO, RM, DTR, UF)
delayed onset, regular monitoring, difficulty to reverse, unexpected fluctuations
52
warfarin onset can take up to how many days?
5
53
what is the therapeutic INR range for warfarin?
2.0-3.0
54
treatment with oral anticoagulants is best guided by measurement of what?
prothrombin time
55
Warfarin and major elective surgery:
1. before major surgery, goal is to get PT to return to what % of normal range?
2. before major surgery, goal is to get INR less than what?
3. stop warfarin what day range before major surgery?
4. high risk pts (eg. prosthetic heart valve) may need what before major surgery?
5. restart warfarin what day range after surgery?
1. 20%
2. < 1.5
3. 1-5 days
4. UFH bridge
5. 1-7 days
56
Warfarin emergency surgeries:
1. What are the 3 immediate warfarin reversal agents? (PCC, P, F)
2. what other thing can be given but it doesn't immediately reverse INR?
3. does FFP bring INR to baseline?
4. how many units of FFP to bring INR to 1.4-1.6?
1. prothrombin complex concentrates, procoagulants, FFP
2. vitamin K
3. no
4. 4 units
57
what are the 3 new oral agents? (DAR)
dabigatran, apixaban, rivaroxaban
58
Dabigatran (pradaxa)
1. what is MOA?
2. used to treat what 2 things? (D, P)
3. reduces the risk of what 2 things in pts with a fib? (S, SE)
4. what 2 labs and which is preferred?
5. dose adjustment for what pts?
1. direct thrombin inhibitor
2. DVT, PE
3. stroke, systemic emobli
4. thrombin time, aPTT; thrombin time
5. renal
59
Rivaroxaban
1. what is MOA?
2. stop how many hours before surgery for normal renal pts?
3. stop how many hours before surgery for renal dysfunction?
4. is monitoring needed?
5. what is the one current use?
6. what are the 4 future indications? (treatment of what 2 things, what rhythm, what syndrome, management of what?
1. direct factor Xa inhibitor
2. 24 hours
3. 48 hours
4. no
5. total hip or knee arthroplasty
6. CVT and PE, a fib, acute coronary syndrome, HIIT
60
Apixaban
1. what is MOA?
2. does it need monitoring?
1. direct factor Xa inhibitor
| 2. no
61
New oral anticoags:
1. for low risk surgery, stop how many hours before and restart how many hours after?
2. for medium to high risk surgery, stop how many days before and restart when?
1. 24 hours, 24 hours
| 2. 5 days, when risk of bleeding subsides
62
Anticoags:
1. what oral agent inhibits thrombin? (D)
2. what 2 oral agents inhibit factor Xa? (R,A)
3. what med inhibits factor Xa and thrombin?
4. what 2 parenteral meds inhibit factor Xa? (E,F)
5. what 4 parenteral meds inhibit thrombin? (B, A, L, D)
1. Dabigatran
2. Rivaroxaban, Apixaban
3. UFH
4. Enoxaparin, fondaparinux
5. bivalirudin, argatroban, lepirudin, desirudin
63
what are the 7 plt inhibitors? (AATTEDD)
aspirin, abcixmab, tirofiban, thienopyridines, eptifibatide, dipyridamole, dextran
64
Aspirin:
1. works by inhibiting what enzyme and preventing the formation of what? (C, T)
2. major therapy for what 2 diseases? (AVD, CA)
3. stop taking what day range before surgery?
4. does it last the life of the plt?
5. what range of plt days is that?
6. resume how many hours after surgery once hemostasis?
1. cyclooxygenase, thromboxane A2
2. atherosclerotic vascular disease, coronary artery disease
3. 7-10 days
4. yes
5. 7-10 days
6. 24 hours
65
Thienopyridines:
1. name the 3 agents (PCT)
2. what receptor do they bind to on plts and what do they block from binding?
3. do they bind reversibly or irreversibly?
4. by binding they don't allow plts to do what 2 things? (A, A)
1. prasugrel, clopidogrel, ticagrelor
2. P2Y, ADP
3. irreversibly
4. activate and aggregate
66
dual therapy with ASA and a thienopyridine improved outcomes in pts with what syndrome and undergoing what intervention?
acute coronary syndrome, percutaneous intervention
67
Dipyridamole:
1. what does it increase in plts to inhibit their function?
2. can be used in cardiac stress testing d/t its what effects?
3. used in combo with ASA to prevent what in pts who cannot take thienopyridines? (S)
1. cAMP
2. coronary vasodilatory effects
3. stroke
68
increasing cAMP in plts prevents them from doing what?
aggregating
69
Dextran:
1. binds to plts and inhibits their what? (F)
2. reduces thrombus after what surgery (C)
1. function
| 2. carotid
70
Stop ASA and thienopyridines how many days before elective surgery?
7 days
71
How many months is an appropriate course of thienopyridines in drug eluting stents?
12 months
72
How many months is an appropriate course of thienopyridines in bare metal stents?
1 month
73
What should be avoided until ASA and thienopyridines effects are gone? (R)
regional
74
what are the 3 glycoprotein IIb/IIIa antagonists? (A,T,E)
abciximab, tirofiban, eptifibatide
75
glycoprotein IIb/IIIa antagonists:
1. bind or competitively inhibit what receptor that is important for plt what? (F, A)
2. reduce ischemic events related to what syndrome and what intervention?
3. what is the antidote for all agents? (D)
4. what is their AE? (T)
5. mainly replaced by thienopyridines d/t what 2 reasons? (C, ID)
1. fibrinogen receptor, aggregation
2. ACS, PCI
3. dialysis
4. thrombocytopenia
5. cost, improved data
76
Elimination half life (hours, range)
1. Abciximab
2. Tirofiban
3. Eptifibatide
1. 12-24 hours
2. 2-4 hours
3. 2-4 hours
77
Elimination route:
1. Abciximab
2. Tirofiban
3. Eptifibatide
1. plasma proteases
2. renal
3. renal and biliary
78
stop how many hours before surgery:
1. Abciximab
2. Tirofiban
3. Eptifibatide
1. 72 hours
2. 24 hours
3. 24 hours
79
what lab test is best predictor of functional plts? (BT)
bleeding time
80
what lab test assesses dysfunctional plts and the causes of their pathology? (PFA)
plt function analysis
81
what lab test measures plasma clarit and light scatter of plt aggregate agents? (PAS)
plt aggregation studies
82
what are the 6 plt tests? (PC, BT, PFA, C/E, C/AD, PAS)
plt count, bleeding time, plt function analysis, collagen/epinephrine, collagen/adenosine diphosphate, plt aggregation studies
83
what are the 5 coagulation tests? (PT, PTT, TT, F, ACT)
prothrombin time, partial thromboplastin time, thrombin time, fibrinogen, activated coagulation time
84
what are the 3 fibrinolysis tests? (TT, FFDP, FDDA)
thrombin time, fibrinogen-fibrin degradation products, fibrin D-dimer assay
85
if fibrinogen is < 100 mg/dL what do you give? (C)
cryo
86
bleeding time should be less than how many minutes?
11 minutes
87
plt count is what range in hundreds of thousands?
140,000-450,000 cells/microliter
88
thrombin time is what range of seconds
22-31 seconds
89
PTT is what range of seconds?
24-35 seconds
90
thrombolytic drugs:
1. act as what to convert plasminogen to the fibrinolytic enzyme what? (PA, P)
2. they restore what thru previously occluded arteries and veins (C)
3. useful in what 3 conditions? (AS, PE, AMI)
4. what are the 2 ways they are injected? (S, DASOL)
1. plasminogen activator, plasmin
2. circulation
3. acute stroke, pulm embolism, acute MI
4. systemically, directly at site of lesion
91
what does plasmin do? (LC)
lysis clots
92
what are the 3 thrombolytic drug agents? (SUT)
streptokinase, urokinase, tissue plasminogen activator
93
where is urokinase commonly used? (IA)
intra-arterial
94
what thrombolytic agent is most common?
tissue plasminogen activator (tPA)
95
tPA binds what and converts plasminogen to what within the thrombus? (F, P)
fibrin, plasmin
96
What are 2 risks of thrombolytic drugs? (B, A)
bleeding, angioedema
97
thrombolytic drugs can especially cause bleeding where? (I)
intracranially
98
what 2 things do you give for thrombolytic-agent caused bleeding? (C, P)
cryoprecipitate, plts
