VTE

Question 1

LMWH and spinal/ epidural anesthesia ?

Answer 1

‏LMWH should not be given for 4 hours after use of spinal anaesthesia or after the epidural catheter has been removed and the catheter should not be removed within 12 hours of the most recent injection.

Question 2

CI /cautions with LMWH use:

Answer 2

Known bleeding disorder (e.g. haemophilia, von Willebrand’s disease or acquired coagulopathy)
Active antenatal or postpartum bleeding
Women considered at increased risk of major haemorrhage (e.g. placenta praevia)
Thrombocytopenia (platelet count < 75 × 109/l)
Acute stroke in previous 4 weeks (haemorrhagic or ischaemic)
Severe renal disease (glomerular filtration rate [GFR] < 30 ml/minute/1.73m2)
Severe liver disease (prothrombin time above normal range or known varices)
Uncontrolled hypertension (blood pressure > 200 mmHg systolic or > 120 mmHg diastolic)

Question 3

Virtue’s triad

Answer 3

(hypercoagulation, venous stasis, vascular damage)

Question 4

The most important treatment for DIC

Answer 4

Treatment of the underlying cause.

Question 5

ileo-femoral DVT may present with

Answer 5

lower abdominal pain.

Question 6

A 55-year-old woman is due to come in for total abdominal hysterectomy and bilateral salpingo-oophorectomy for a large mucinous ovarian cyst. She takes sequential HRT for menopausal symptoms. You discuss with her the risk of venous thromboembolism. How long prior to surgery should she stop HRT?
A. 2 weeks
B. 3 weeks
C. 4 weeks
D. 5 weeks
E. 6 weeks

Answer 6

C. 4 weeks

Question 7

The prolongation of PT depends on

Answer 7

reductions in three of the vitamin K–dependent clotting factors (II, VII and IX).

Question 8

Among the Risk factors for developing VTE during pregnancy, The most important of these is

Answer 8

a personal history of thrombosis. 15 to 25 percent of all VTE cases during pregnancy are recurrent events (American College of Obstetricians and Gynecologists, 2020b).

Question 9

important individual risk factor is a genetically determined thrombophilia. An estimated – to – percent of women who develop a venous thrombosis during pregnancy or postpartum have an identifiable underlying procoagulant genetic disorder (American College of Obstetricians and Gynecologists, 2020a).

Answer 9

important individual risk factor is a genetically determined thrombophilia. An estimated 20 to 50 percent of women who develop a venous thrombosis during pregnancy or postpartum have an identifiable underlying procoagulant genetic disorder (American College of Obstetricians and Gynecologists, 2020a).

Question 10

Synthesized in the liver one of the most important inhibitors of thrombin and inactivates thrombin and factor Xa

Answer 10

antithrombin

Question 11

Antithrombin deficiency may result from hundreds of different mutations that are almost always autosomal ——.

Answer 11

Antithrombin deficiency may result from hundreds of different mutations that are almost always autosomal dominant.

Question 12

Antithrombin Deficiency types

Answer 12

Type I deficiency results from reduced synthesis of biologically normal antithrombin, and type II deficiency is characterized by normal levels of antithrombin with reduced functional activity.

Question 13

Antithrombin deficiency is associated with a — to – fold higher relative risk of VTE in the general population and a — fold increased risk of thromboembolic complications during pregnancy

Answer 13

Antithrombin deficiency is associated with a 25- to 50fold higher relative risk of VTE in the general population and a sixfold increased risk of thromboembolic complications during pregnancy

Question 14

factor V Leiden Mutation result from …..?

Answer 14

This missense mutation results from a substitution of glutamine for arginine at position 506 in the factor V polypeptide.

Question 15

Women who are heterozygous for factor V Leiden account for approximately – percent of VTE cases during pregnancy.

Answer 15

Women who are heterozygous for factor V Leiden account for approximately 40 percent of VTE cases during pregnancy.

Question 16

the actual risk of VTE among pregnant women who are heterozygous Factor V Leiden Mutation and who do not have a personal history or a first-degree relative with a thrombotic episode before age 50 years is – to – events per 1000 births.
% with a personal or family history ? % with homozygous with and without family hx

Answer 16

the actual risk of VTE among pregnant women who are heterozygous and who do not have a personal history or a first-degree relative with a thrombotic episode before age 50 years is 5 to 12 events per 1000 births
this risk is at least 10 percent among pregnant women with a personal or family history. Pregnant women who are homozygous without a personal or family history have a 1to 4-percent risk for VTE, whereas those with such a history have an approximately 17-percent risk (American College of Obstetricians and Gynecologists, 2020a).

Question 17

heterozygous carrier of Prothrombin G20210A Mutation with a history of VTE, the risk exceeds – percent. Without such a history, heterozygous carriers of the mutation have less than a –percent risk of VTE during pregnancy (American College of Obstetricians and Gynecologists, 2020a).

Answer 17

heterozygous carrier of Prothrombin G20210A Mutation with a history of VTE, the risk exceeds 10 percent. Without such a history, heterozygous carriers of the mutation have less than a 1percent risk of VTE during pregnancy (American College of Obstetricians and Gynecologists, 2020a).

Question 18

Hyperhomocysteinemia

Answer 18

The most common cause of elevated homocysteine is the C667T thermolabile mutation of the 5, 10– methylene–tetrahydrofolate reductase (MTHFR) enzyme. Inheritance is autosomal recessive.

Question 19

the most common sole antiphospholipid antibody present

Answer 19

anticardiolipin antibody is the most common sole antiphospholipid antibody present

Question 20

Women with APS have a – to –percent risk of thrombosis during pregnancy or the puerperium.

Answer 20

Women with APS have a 5- to 12-percent risk of thrombosis during pregnancy or the puerperium.

Question 21

The American College of Obstetricians and Gynecologists (2020a) recommends that thrombophilia screening be considered in the following clinical circumstances:

Answer 21

(1) a personal history of VTE with or without a recurrent risk factor such as fractures, surgery, or prolonged immobilization; and (2) a firstdegree relative (parent or sibling) with a history of a high-risk inherited thrombophilia.

Question 22

Important

Answer 22

Methods of screening for the more common inherited thrombophilias, laboratory testing is performed at least 6 weeks after the thrombotic event, while the patient is not pregnant, and when she is not receiving anticoagulation or hormonal therapy. Last, screening for hyperhomocysteinemia is not recommended (American College of Obstetricians and Gynecologists, 2020a).

Question 23

– to – percent of women with a confirmed lower-extremity acute deep-vein thrombosis (DVT) have an asymptomatic pulmonary embolism

Answer 23

30 to 60 percent of women with a confirmed lower-extremity acute deep-vein thrombosis (DVT) have an asymptomatic pulmonary embolism

Question 24

UFH intravenous protocol

Answer 24

initiated with a bolus intravenous dose of 70 to 100 U/kg, which is 5000 to 10,000 U. This is followed by continuous intravenous infusions beginning at 1000 U/hr or 15 to 20 U/kg/hr. This infusion rate is titrated to achieve an aPTT 1.5 to 2.5 times control values (Linnemann, 2016). Intravenous anticoagulation is maintained for about 5 to 7 days, after which treatment is converted to subcutaneous heparin to maintain the aPTT to at least 1.5 to 2.5 times control throughout the dosing interval. For women with lupus anticoagulant, aPTT does not accurately assess heparin anticoagulation, and thus anti–factor Xa levels are preferred.

Question 25

PULMONARY EMBOLISM causes approximately – percent of maternal deaths

Answer 25

PULMONARY EMBOLISM causes approximately 10 percent of maternal deaths

Question 26

In chest CT angiography The estimated fetal radiation exposure averages 0.45 to 0.6 mGy. The estimated maternal breast dose is 10 to 70 mGy (Waksmonski, 2014).

Answer 26

The estimated fetal radiation exposure averages 0.45 to 0.6 mGy. The estimated maternal breast dose is 10 to 70 mGy (Waksmonski, 2014).

Question 27

In V/Q scan There is negligible fetal and maternal breast radiation exposure—— to — mGy.

Answer 27

In V/Q scan There is negligible fetal and maternal breast radiation exposure—0.1 to 0.4 mGy.

Question 28

the reference test for pulmonary embolism.

Answer 28

Intravascular Pulmonary Angiography This requires catheterization of the right side of the heart

Question 29

Timing for neuroaxial in relation to pharmacological anticoagulant

Answer 29

Question 30

Warfarin heparin bridging protocol

Answer 30

During bridging, warfarin is stopped several days before surgery, and heparin is begun. In those with a therapeutic INR (between 2.0 and 3.0), approximately S to 6 days are required for this ratio to reach 1.5. Once this is achieved, surgery can safely proceed. During bridging therapy, the last dose of LMWH is administered 24 hours prior to surgery. With UFH, therapy is halted 4 to 6 hours prior to surgery (Douketis, 2012).