CA IC1-IC9

Question 1

what is hematocrit

Answer 1

relative volume of RBC out of total blood volume

Question 2

average hematocrit for men and women

Answer 2

46 and 42

Question 3

reduced oxygen-carrying capacity of blood, can be due to:

Answer 3

blood donation
hypoxia/low RBC levels of function
restricted blood flow to kidneys

Question 4

hemoglobin is broken down into heme and globin. how is heme used in the body?

Answer 4

store in liver or reuse in bone marrow as ferritin
used as bilirubin & secreted into bile

Question 5

hemoglobin is broken down into heme and globin. how is globin used in the body?

Answer 5

metabolised to amino acids and go back to blood stream

Question 6

3 phases of hemostasis and how long it takes

Answer 6

1. vasoconstriction (immediate)
2. platelet plug (in seconds)
3. fibrin clot (in minutes)

Question 7

how is platelet adhesion mediated?

Answer 7

by von Willebrand’s factor (vWF) aka plasma protein produced by platelets.

Question 8

2 platelet agonists

Answer 8

ADP - attracts and activates more platelets

thromboxane A2 - promote aggregation and further vasoconstriction

Question 9

which factor helps the fibrin mesh form?

Answer 9

Factor XIII (fibrin stabilising factor)

Question 10

how is extrinsic pathway triggered?

Answer 10

by release of tissue factor/thromboplastin (factor III) by damaged tissues

Question 11

how is intrinsic pathway triggered

Answer 11

exposure to collagen fibres or exposure to foreign surface

Question 12

explain intrinsic pathway

Answer 12

platelet phospholipids cause conformational change, activates Factor XII

XIIa activates XI

XIa + IV (calcium) activates IX

IX + IV (ca) +VIIIa activates X

Xa + IV (ca) + Va activates II (prothrombin to thrombin)

IIa (thrombin) cleaves and activates I (fibrinogen to fibrin)

Ia + XIIIa forms fibrin

Question 13

explain extrinsic pathway

Answer 13

damaged tissues release tissue factor/thromboplastin (III) which activates VII

VIIa + IV (ca) activates X

Xa + IV (Ca) + Va activates II (prothrombin to thrombin)

IIa activates I (fibrinogen to fibrin)

Ia + XIIIa forms fibrin mesh

Question 14

Virchow’s triad

Answer 14

Stasis (immobility, abnormal blood flow in veins)
Hypercoagulability (genetic disorders or acquired conditions)
Vascular wall injury (hypertension, atherosclerosis)

Question 15

what is D-dimer a marker for

Answer 15

fibrin degradation products

Question 16

Is PTT a measure of intrinsic/extrinsic + common coagulation pathway?

Answer 16

intrinsic

Question 17

is PT a measure of intrinsic/extrinsic + common coagulation pathway?

Answer 17

extrinsic

Question 18

isolated prolongation of PT, what factor deficiency to consider?

Answer 18

factor VII (7)

Question 19

isolated prolongation of PTT, what factor deficiency to consider?

Answer 19

factors VIII, IX, XI, XII (8, 9, 11, 12)

Question 20

which DOAC is metabolised by CYP3A4 enzyme?

Answer 20

Apixaban
Rivaroxaban

Question 21

which DOAC is is a substrate of pgp transporter?

Answer 21

apixaban
dabigatran
rivaroxaban

Question 22

which DOAC is is a substrate of BCRP transporter?

Answer 22

apixaban
rivaroxaban

Question 23

which DOAC is is a substrate of OATP transporter?

Answer 23

rivaroxaban (substrate of OAT3)

Question 24

dose for dabigatran VTE treatment + renal adjustment

Answer 24

parenteral coagulant for >= 5 days
150mg BD

avoid in CrCl < 50 + concomitant PGP inhibitor

Question 25

dose for rivaroxaban VTE treatment + renal adjustment

Answer 25

15mg BD x 21d 20mg OD up to 6m 10mg OM (prophylactic dose) avoid in CrCl < 30 CrCl 30-50: consider 15mg OD (after 21d) if bleeding risk>VTE recurrence risk

Question 26

dose for apixaban VTE treatment + renal adjustment

Answer 26

10mg BD x 7d 5mg BD up to 6m 2.5mg BD (prophylactic dose) caution in CrCl 15-29; avoid HD

Question 27

dose for edoxaban VTE treatment + renal adjustment

Answer 27

parenteral coagulant for >= 5 days 60mg/day half dose (30mg/day) if CrCl 30-50 or weight <=60kg not recommended in CrCl > 95

Question 28

dose for dabigatran SPAF + renal adjustment

Answer 28

150mg BD if >=80yo/use PGP inhibitor/HBR: 110mg BD no need if CrCl 30-50 unless DDI CI in CrCl < 30

Question 29

dose for rivaroxaban SPAF + renal adjustment

Answer 29

20mg/day CrCl 30-50: 15mg/day CrCl 15-29: caution (FDA say can 15mg/day) not for CrCl < 15

Question 30

dose for apixaban SPAF + renal adjustment

Answer 30

5mg BD 2.5mg BD if any 2: - >=80yo - <=60kg - SCr >= 1.5mg/dL or 132.6mmol/L CrCl 15-29: 2.5mg BD not used in <15ml/min & HD consideration

Question 31

dose for edoxaban SPAF + renal adjustment

Answer 31

60mg/day 30mg/day if ANY: - CrCl 30-50 - <=60kg - concomitant verapamil, quinidine, dronedarone [AF agents, antiarrhythmics] CrCl 30-50: 30mg/day CrCl 15-29: 30mg/day not recommended in CrCl < 15

Question 32

dose for dabigatran VTEP

Answer 32

1-4h post surgery 220mg/day x 10d or 28-35d CrCl 30-50: caution and 150mg OM for same duration

Question 33

dose for rivaroxaban VTEP

Answer 33

6-10h post surg 10mg/day x 2 weeks (TKR) or 5 weeks (THR) medically ill: 10mg/day for up to 31-39days

Question 34

dose for apixaban VTEP

Answer 34

12-24h post surg 2.5mg BD x 10-14d or 32-35d

Question 35

dose for edoxaban VTEP

Answer 35

30mg/day

Question 36

dose for UFH VTE treatment

Answer 36

IV 80u/kg bolus 18u/kg/h infusion due to short half life (used in severe renal impairment)

Question 37

dose for LMWH VTE treatment

Answer 37

SQ 1mg/kg Q12H or 1.5mg/kg OD severe renal impairment (CrCl 30-50) - 1mg/kg OD

Question 38

dose for UFH PCI treatment

Answer 38

IV 2000-5000u to achieve ACT of 250-300s. Repeat bolus as needed throughout PCI not to bolus if ACT > 200s

Question 39

dose for UFH VTEP treatment

Answer 39

SQ 5000u Q8-12H for medically ill >= 2h before surgery and until follow ambulatory and no risk of DVT (~10d) space 12 from ortho surgery but 5000u q8-12h up to 35d

Question 40

dose for LMWH VTEP treatment

Answer 40

SQ 40mg OD 30mg BD if very obese for 10-14d up to 35d moderate renal impairment: CrCl 30-50 - 30mg Q12H severe renal impairment: CrCl < 30 - 20 or 30mg OD

Question 41

dose for LMWH PCI treatment

Answer 41

Last SQ LMWH <8h before: no need LMWH Last SQ LMWH 8-12h before: 0.3mg/kg bolus Last SQ LMWH >12h before: use UFH No prior anticoagulant: 0.5-0.75mg/kg IV bolus

Question 43

antibiotics that do not require preemptive adjustment with warfarin?

Answer 43

macrolides, amoxicillin-clavulanate, doxycycline

Question 44

what will cause INR increase?

Answer 44

- alcohol binge - liver disease (clotting factors turnover) - febrile states - fluid retention in liver - hyperthyroidism

Question 45

what will cause INR to decrease

Answer 45

- chronic alcoholism - sudden increase in physical activity - smoking - fluid retention in gut (cannot absorb well) - hypothyroidism

Question 46

why does warfarin require parenteral anticoagulant (LMWH) bridging for the first 4-5 days?

Answer 46

warfarin causes drop in natural anticoagulant Protein C and Protein S in the body, putting the body into a hypercoagulable state

Question 47

INR is a measure of what factors?

Answer 47

II, VII, X (2, 7, 10)

Question 48

Warfarin causes the decrease in which clotting factors?

Answer 48

II, VII, IX, X (2, 7, 9, 10)

Question 49

when is pharmacogenomics testing beneficial for patients?

Answer 49

for those who require warfarin maintenance dose <=21mg/week and >= 49mg/week (extreme ends)

Question 50

irreversible P2Y12 inhibitors

Answer 50

- clopidogrel - prasugrel

Question 51

reversible P2Y12 inhibitors?

Answer 51

ticagrelor

Question 52

MOA of P2Y12 inhibitor

Answer 52

binds (ir)reversibly to P2Y12 component on ADP receptor on platelet surface

Question 53

only case to use tenecteplase

Answer 53

AMI (ACS)