Clinical Therapeutics - AF and VTEs Flashcards
What is an Ischaemic event?
Reduced blood flow to the heart, causing pain
What can an ECG tell us?
The type of ACS
The part of the heart that is affected
What’s the GRACE score?
Predicits the 6 month morality rate –> caused by another CV related event
What is Atrial Fibrillation (AF)?
When the AVN recieves more electrical impulses than it can conduct…..resulting in a fast, irregular ventricular rhythm
What are the 4 terms associated with AF?
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
What are the 3 main elements in the managment of AF?
Rate Control
Rhythm Control
Stroke Prevention
What are the most common rate limiting CCBs?
Diltiazem (off label) and Veramapril
Contraindicated with B-blockers
Explain a little about Digoxin
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
Why is Dronedarone safer than Amiodarone?
As it contains no iodine groups, so less change of thyroid diseases developing
It is less efficious however
What’s a ‘Pill-in-the-pocket’?
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
What’s a Cardiac Catheter Ablation?
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
How is the risk of stroke assessed in AF?
The CHA2/DS2/VASc score
How is the risk of bleeding in AF assessed?
The HAS-BLED score
What is a VTE?
And what are the 3 versions?
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
What are the symptoms of a DVT?
And how is it diagnosed?
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
What are the symptoms of a PE?
And how is this diagnosed?
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
What are 4 further investigations that can be used for DVT/PE?
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)
Dalteparin/Enoxaparin are example of what?
And how do these work?
Low Molecular Weight Heparins (LMWHs)
Bind to antithrombin III (ATIII), increasing its inhibitory action on Factor Xa
Given SC
What is Unfractioned Heparin (UFH)?
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
When would UFHs be preffered over LMWHs?
In severely impaired renal function
When there is a high risk of bleeding –> short half life so can be removed quicker
What’s Alteplase?
A recombinant tissue plasminogen activator (r-tPA)
Converts plasminogen to plasmin –> actively degrading the clot
Only in “Massive PE”
Rivaroxaban and Dabigatran are both DOACs, but how do they function differently?
Rivaroxaban –> Inhibit Factor Xa
Should be taken with food
Dabigatran –> Inhibt Factor IIa
Both CYP substrates!!
How does Warfarin work?
Inhibits Vitamin K epoxide reductase and Vitamin K quinone reductase
What are the 3 types of mechanical thromboprophylaxis?
Anti-embolism stocking
Foot impulse devices
Intermittent Pneumatic Compression (IPC) devices
What is a Inferior Vena Cava (IVC) filter?
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
