Clinical Therapeutics - AF and VTEs

Question 1

What is an Ischaemic event?

Answer 1

Reduced blood flow to the heart, causing pain

Question 2

What can an ECG tell us?

Answer 2

The type of ACS

The part of the heart that is affected

Question 3

What’s the GRACE score?

Answer 3

Predicits the 6 month morality rate –> caused by another CV related event

Question 4

What is Atrial Fibrillation (AF)?

Answer 4

When the AVN recieves more electrical impulses than it can conduct…..resulting in a fast, irregular ventricular rhythm

Question 5

What are the 4 terms associated with AF?

Answer 5

Paroxysmal –> Episodes of less than 30s, but less than a week

Persistant –> Episodes that occur for longer than a week

Permanent –> AF that fails to terminate after cardioversion or relapses within 24 hours

Can also be AF thats occured for over a year where cardioversion hasnt be tried

Lone –> Not associated with any other medical condition

Question 6

What are the 3 main elements in the managment of AF?

Answer 6

Rate Control

Rhythm Control

Stroke Prevention

Question 7

What are the most common rate limiting CCBs?

Answer 7

Diltiazem (off label) and Veramapril

Contraindicated with B-blockers

Question 8

Explain a little about Digoxin

Answer 8

Used for rate control in combination with a B-blocker or rate-limiting CCB

70% renally cleared, so those with a renal impairment need a dose change

Vision can be yellow as a side effect –> occurs quickly so no need for blood tests

HR does need to be monitored

Question 9

Why is Dronedarone safer than Amiodarone?

Answer 9

As it contains no iodine groups, so less change of thyroid diseases developing

It is less efficious however

Question 10

What’s a ‘Pill-in-the-pocket’?

Answer 10

A single dose of flecanide or propafenone to be taken when symptoms of AF (paroxysms) start to develop

Must have over 100 systolic BP and over 70 BPM

Question 11

What’s a Cardiac Catheter Ablation?

Answer 11

When a catheter is inserted from the groin, into the heart via the vena cava

It emits radiofrequency energy to damage the tiny parts of the cardiac tissue that is caused the abnormal conduction

Question 12

How is the risk of stroke assessed in AF?

Answer 12

The CHA2/DS2/VASc score

Question 13

How is the risk of bleeding in AF assessed?

Answer 13

The HAS-BLED score

Question 14

What is a VTE?

And what are the 3 versions?

Answer 14

Venous thromboembolism (VTE) –> An undesirable blood clotting in the venous system

Deep Vein Thrombosis (DVT) –> A clot in a deep vein, usually in the leg

Pulmonary Embolism (PE) –> Fragments from a DVT break off and cause a clot in a pulmonary artery…..preventing blood from reaching the lungs for gaseous exchange

Transient Ischaemic Attack (TIA) –> When fragments from DVTs break off and block cerebral arteries

Also known as ischaemic stroke

Question 15

What are the symptoms of a DVT?

And how is it diagnosed?

Answer 15

Usually unilateral

Pain/swelling and tenderness of the calf (usually)

Warm skin in the affected area

Pitting Oedema

Prominant superficial veins

Diagnosed by the Two Level Wells Score

Question 16

What are the symptoms of a PE?

And how is this diagnosed?

Answer 16

Concurrent DVT

Breathlessness

Cough –> dry and blood stained

Tachycardia and Tachpnoea (high RR)

Chest pain –> worse on inspiration

Hypotension –> possible synocope

Hypoxia/Cyanosis

Diagnosed by the Two Level Wells Score

Question 17

What are 4 further investigations that can be used for DVT/PE?

Answer 17

D-Dimer Test –> Positive is suggestive of a DVT/PE (as found when a thrombus is degraded)

Venous Ultrasound –> An imaging technique used to visualise venous blood clots in situ (best for DVT)

CT Pulmonary Angiography (CTPA) –> Imaging technique used to visulalise thorbuses in pulmonary veins (so best for PE)

Ventilation-Perfusion (VQ) Scan –> Radiopharmaceutcial material is used to visualise the lungs (best for PE)

Question 18

Dalteparin/Enoxaparin are example of what?

And how do these work?

Answer 18

Low Molecular Weight Heparins (LMWHs)

Bind to antithrombin III (ATIII), increasing its inhibitory action on Factor Xa

Given SC

Question 19

What is Unfractioned Heparin (UFH)?

Answer 19

Same pharmacological effect as LMWHs

Has a much larger polysaccharide chain

Thromboprophylaxis –> SC, bolus injection

Treatment of DVT/PE –> IV loading dose….then continous

APPT ratio needs to measured –> Activated partial thromboplastin time (how quickly blood clots) / Normal APTT

Normally between 2-3

Question 20

When would UFHs be preffered over LMWHs?

Answer 20

In severely impaired renal function

When there is a high risk of bleeding –> short half life so can be removed quicker

Question 21

What’s Alteplase?

Answer 21

A recombinant tissue plasminogen activator (r-tPA)

Converts plasminogen to plasmin –> actively degrading the clot

Only in “Massive PE”

Question 22

Rivaroxaban and Dabigatran are both DOACs, but how do they function differently?

Answer 22

Rivaroxaban –> Inhibit Factor Xa

Should be taken with food

Dabigatran –> Inhibt Factor IIa

Both CYP substrates!!

Question 23

How does Warfarin work?

Answer 23

Inhibits Vitamin K epoxide reductase and Vitamin K quinone reductase

Question 24

What are the 3 types of mechanical thromboprophylaxis?

Answer 24

Anti-embolism stocking

Foot impulse devices

Intermittent Pneumatic Compression (IPC) devices

Question 25

What is a Inferior Vena Cava (IVC) filter?

Answer 25

A wire meshwork fitted into the lumen of the inferior vena cava to prevent clots from entering the right artery

For patients with a high risk of VTE