Coronary Heart Disease and Stroke Flashcards
What is cardiovascular disease?
disease of the heart & blood vessels
Most common manifestation of CVD is…
coronary heart disease also known as
- coronary artery disease
- ischaemic heart disease
What are the symptoms of angina pectoris
- crushing pain in chest that may radiate to arm, jaw or shoulder
- normally on the left side
- usually on exertion
What are the pathophysiological problems in CHD?
narrowing of coronary arteries by atheroma (fatty gunge)
- so not enough oxygen reaches the heart muscle
- so oxygen DEMAND succeeds SUPPLY
- so heart muscle is hypoxic
- so heart cells DIE
What are the consequences of the heart working anaerobically?
cells don’t work well (less blood pumped);
- may “misbehave” electrically (conduction problems & arrhythmias)
- pain
When heart oxygen demand exceeds supply how can you help the demand and with what drugs?
- Reduce heart rate - BETA BLOCKERS
- Reduce heart filling/ contraction strength - NITROVASODILATORS
- Reduced arterial resistance - BLOOD PRESSURE LOWERING DRUGS
When heart oxygen demand exceeds supply how can you help the supply and with what drugs?
- open up heart arteries -
- prevent atheroma formation - cholesterol lowering drugs. eg. STATINS
- Decrease risk of clotting - ANTI-PLATELET DRUGS
What causes myocardial infarction?
coronary artery completely blocked, typically by blood clot on ruptured plaque
What 4 types of drugs are used to treat heart attack and why?
- painkillers eg. morphine and diamorphine
- anti-arrhythmia drugs - injured cells often misbehave
- thrombolytic - clot busting drugs
- anti-platelet drugs - as blood is less likely to form a clot again
What is the most common Nitrates (nitrovasodilators) used?
Glyceryl Trinitrate (GTN)
How is GTN (glyceryl trinitrate) administered?
Sublingual tablet, nasal spray, transdermal patch
What is the actions of nitrates?
- Nitrates produce nitric oxide
- this increases cGMP in muscle cells
- muscle relaxes = vessels dilate
nitrovasodilators dilate..
both arteries and veins
What happens when you dilate systemic arteries ?
- less risistence (reduced BP)
- Less work for the heart ( less oxygen demand)
What happens when you dilate large veins?
- this is the biggest effect
- more blood in venous system - less back to the heart
- heart fills less - less work - less oxygen demand
What happens when you dilate cerebral arteries?
cerebral blood flow increased - throbbing or pounding headache
What are the side effects of nitrates?
- throbbing headache
- dizziness especially on getting up - lowered BP
What are the cautions when taking nitrates?
- Other BP-lowering drugs (BP can be too low!)
- Other drugs acting on NO pathway e.g. Sildenafil
Statins have few side effects what are they?
- GI upset (usually wears off)
- abnormal liver tests (usually mild)
- muscle problems (myopathy – rare but serious)
What are statins used for?
Statins are a group of medicines that can help lower the level of low-density lipoprotein (LDL) cholesterol in the blood.
What is the difference between a thromboembolic infarction and a intracranial haemorrhage?
A thromboembolic infarction is a BLOCKAGE that stops the blood of blood to an area of the brain.
A intracranial haemorrhage is DAMAGE/BLEED. Blood leaks into the brain.
What are the risk of clot busters given to stroke patients?
risk of intracerebral bleeding
Modern clot busting drugs are ‘recombinant tissue plasminogen activators’ or ‘r-tPAs’. What is the most common example of this?
Alteplase
How are r-tPAs administered
IV injection by specialist nurses’
Are r-tPAs short or long acting ?
short acting
Must confirm ISCHAEMIC event before giving tPA but how is this done?
brain imaging (CT or MRI scan)
How do antiplatelet drugs administer in stroke patients work?
inhibit platelet aggregation & thrombus formation by preventing GPIIa/IIIb receptor expression.
How do anti-coagulants drugs administered in stroke patients work?
- reduce activation of clotting cascade
- fibrin?
Targets for modifying thrombosis process?
Modify coagulation
most successful in venous thrombosis
(lower pressure, slower flow)
Modify platelet aggregation
important in arterial thrombosis
Modify clot, thrombus breakdown
after prophylaxis fails
How does aspirin work in preventing ischaemic stroke?
→ Inhibits cyclo-oxygenase (COX1).
→ Prevents thromboxane formation
How does dipyridamole work in preventing ischaemic stroke?
→ Inhibits thromboxane synthase
→ Prevents thromboxane formation
Which drug can be used in conjunction with aspirin in preventing ischaemic stroke?
dipyridamole
What are the actions of clopidogrel in treating ischaemic stroke?
Clopidogrel (& similar agents) → antagonize actions of ADP at purinergic (ADP) receptors
What are the actions of abciximab in ischaemic stroke?
Abciximab prevents linking of platelets to fibres
What type of drug is abciximab?
anti-platelet
What type of drug is dipyridamole?
anti- platelet
What type of drug is alteplase?
Fibrinolytic Agents
What type of drug is clopidogrel?
anti-platelet
heparin is an anti-coagulant, how is it administered?
IV
What are the actions of heparin?
activates (one of) body’s own anti-clotting molecules, antithrombin III.
What type of drug is warfarin?
anti-coagulant
What are the actions of warfarin?
acts on the liver to inhibit the enzyme Vitamin K reductase.
- action (gradually) diminishing concs. of clotting factors
- eventually body not being able to make as much fibrin
How can you reverse the actions of anticoagulation?
- If not in hurry, can stop anticoagulant drugs & wait
- Vitamin K to reverse warfarin action (still takes a while – why?)
- URGENT: give clotting factors
What are the long-Term Treatment of Ischaemic Stroke?
. Antiplatelet therapy:
Long-term anti-platelet therapy reduces substantially the incidence of further infarction.
Secondary Prevention
e.g. combined aspirin (75 mg day) and dipyridamole (200 mg 2x day)
