ACS & Stroke Flashcards
What are acute coronary syndromes (ACS)?
A group of disorders characterised by severe chest pain radiating to left arm and jaw
Not relieved by rest and lasts more than a few minutes.
What are the three main categories of acute coronary syndromes?
- Unstable angina
- NSTEMI: Non ST elevated myocardial infarction
- STEMI: ST elevated myocardial infarction
What causes acute coronary syndromes?
Blockage of blood vessel in the heart due to an inappropriate blood clot
This leads to ischaemia and release of pain mediators.
What distinguishes STEMI from NSTEMI?
- STEMI: blockage is total, causing tissue damage and muscle death
- NSTEMI: blockage is partial, resulting in less extensive damage
How is stable angina different from acute coronary syndromes?
Stable angina is relieved by rest or GTN and usually has a normal ECG
May show differences during exertion.
What is the primary goal in treating acute coronary syndromes?
Restore blood supply and avoid further heart attacks
What are common medications used to treat acute coronary syndromes?
- GTN for pain relief
- Beta blockers to reduce cardiac workload
- Antiplatelet drugs
- Percutaneous coronary intervention
What characterizes a stroke?
Blocked vessel (85%) or burst vessel (15%)
What are symptoms of a haemorrhagic stroke?
- “Thunderclap” headache
- Nausea
- Vomiting
- Seizures
- Lost consciousness
What is a transient ischaemic attack (TIA)?
Temporary blockage lasting minutes to hours with full recovery
It is a warning sign for potential future strokes.
What is the mechanism of damage in strokes?
- Ischaemia
- Release of glutamate
- Excitotoxicity
What is essential for treating ischaemic stroke?
Restore blood supply using thrombolytic drugs to dissolve the blood clot
What are the main risk factors for acute coronary syndromes and stroke?
- Hypertension
- Dietary factors
- Diabetes
- High LDL
- High BMI (obesity)
- Smoking
- Poor kidney function
- Lack of exercise
- Genetic factors
What is haemostasis?
Prevention of blood loss after vessel damage
What are the two types of thrombosis?
- Venous thrombosis
- Arterial thrombosis
What is primary haemostasis?
The first line of defense against blood loss involving platelets
What is the role of platelets in blood clotting?
Activate, adhere, and aggregate via fibrinogen
What is the coagulation cascade?
Comprises extrinsic, intrinsic, and common pathways
What is the most commonly used antiplatelet drug for secondary prevention?
Aspirin
What are side effects of aspirin?
- Extended bleeding
- Irritating to stomach and GI tract
- Ulcers
- Reye’s syndrome (under 16s)
- Can provoke asthma
What are ADP receptor inhibitors?
- Clopidogrel
- Prasugrel
- Ticagrelor
What is a common side effect of ADP inhibitors?
Extended bleeding
When are antiplatelet drugs used?
- Secondary prevention in stable angina
- ACS with DAPT: Aspirin + ticagrelor, prasugrel, or clopidogrel
- Stroke or TIA
What are the types of anticoagulants?
- Heparin
- Low molecular weight heparin (LMWH)
- Direct acting oral anticoagulants (DOACs)
What are common side effects of heparin?
- Excess bleeding
- Thrombocytopenia
What is the function of warfarin?
Vitamin K antagonist used as an anticoagulant
What is the INR in relation to warfarin?
International Normalised Ratio for monitoring clotting time
What is the mechanism of action of thrombolytics?
Increases plasmin production to dissolve blood clots
What is a significant risk when using thrombolytics?
Increased bleeding time and haemorrhage
What is the main purpose of percutaneous coronary intervention (PCI)?
To open up a blocked artery during a myocardial infarction
What are potential side effects of PCI?
- Heart attack
- Stroke
- Restenosis
What are the two main types of COX enzymes?
COX-1 and COX-2
COX-1 is a housekeeping gene found in many tissues, while COX-2 is found in limited tissues but can be induced during inflammation.
What is the primary role of COX-1?
GI tract mucus secretion
COX-1 plays a crucial role in maintaining the protective lining of the gastrointestinal tract.
What was the original hypothesis regarding the role of COX-2?
COX-2 was thought to be beneficial in inflammation
COX-2 is induced during inflammation and was originally assumed to only have positive effects.
What is a significant feature of Celecoxib?
30-fold selective COX-2 inhibitor
Celecoxib was introduced in 1999 as a selective COX-2 inhibitor to reduce pain without affecting the GI tract.
What is the selectivity of Rofecoxib for COX-2?
300-fold selective COX-2 inhibitor
Rofecoxib, also known as Vioxx, was marketed as a highly selective COX-2 inhibitor.
What serious health issues were associated with Rofecoxib?
Heart attacks and strokes
Rofecoxib was withdrawn in 2004 due to its association with over 40,000 deaths from cardiovascular events.
What action did the FDA take regarding coxibs?
Banned all coxibs except celecoxib
The FDA’s action was in response to the cardiovascular risks associated with selective COX-2 inhibitors.
What is Hirudo medicinalis commonly known as?
Medical leech
Medical leeches have been used historically for bloodletting to ‘balance the humours’.
What is the role of Hirudin?
Blocks thrombin and prevents production of fibrin
Hirudin is a 65 amino acid peptide that is crucial in anticoagulant therapy.
What are some forms of Hirudin used in therapy?
Desirudin and Bivalirudin
Desirudin is a recombinant form, while Bivalirudin is a 20 amino acid synthetic analogue.
How must Hirudin be administered?
Must be given IV
Hirudin is typically administered intravenously, especially during procedures like PCI and orthopedic surgery.
Fill in the blank: Rofecoxib may be responsible for _______ deaths.
40000+
This number reflects the estimated deaths linked to cardiovascular issues from Rofecoxib use.
What are ACSs?
A spectrum of conditions caused by reduced blood flow to the heart
Including unstable angina, NSTEMI and STEMI
What is alteplase?
A recombinant tissue plasminogen activator (tPA) used to dissolve blood clots in conditions like stroke (and sometimes myocardial infarction)
What is angioplasty?
A procedure to restore blood flow by inflating a small balloon inside a narrowed or blocked artery
What is atrial fibrillation?
An irregular rapid heart rhythm that increases the risk of stroke and blood clots
What is the role of antithrombin III?
Inhibits thrombin and factor Xa, helping to regulate blood coagulation
What is vitamin K?
A fat-soluble vitamin essential for the synthesis of clotting factors in the liver
