Coronary heart disease Flashcards
What are the 2 main forms thromboembolic diseases?
- Arterial Thrombosis
- Venous Thrombosis
What are the examples of arterial thrombosis?
- Acute myocardial infarction (AMI)
- Transient ischaemic attacks (TIAs)
- Cerebral vascular infarcts/accidents (CVAs)
What are the examples of venous thrombosis?
- Deep vein thrombosis (DVT)
- Pulmonary embolism (PE)
What is the 3rd group of thromboembolic diseases?
Inherited/Acquired thrombosis
- Thrombophilia
This is a series of genetic diseases, so where theres an increased susceptibility to clotting, which can cause both arterial or venous thrombi.
What is arterial thrombosis?
- Occurs as a result of rupture of atherosclerotic plaques
- It results in platelet deposition and vessel occlusion
- Often known as “White thrombi”, relating to the colour of its platelet rich core.
What is venous thrombosis
- Often occurs in normal vessels
- Majority start In the deep vein of the leg
- Often known as “Red thrombi”, relating to the colour of its platelet rich core.
What is coronary heart disease?
Coronary heart disease is a condition in which the vascular supply to the heart is impeded/obstructed by atheroma (fatty plaques formed on the inside of the blood vessel walls), thrombosis or spasm.
- Ultimately reduction of blood flow to the blood.
- If the reduction of blood flow is severe enough, it will cause symptoms of ischemia or lack of oxygen secondary to lack of blood supply.
- Has the potential to damage the cardiac muscle
What are the series of events that happens after inadequate blood supply?
Inadequate blood supply causes an inadequate reduction in oxygen supply to the heart. As a consequence the patient will develop ischaemic chest pain. Chest pain the the main symptom of Ischaemic Heart Disease (IHD).
Depending of the extent of that reduction in blood supply, can cause various clinical issues:
- Stable angina (sometimes called ‘Exercise induced angina’)
- Acute Coronary Syndrome (ACS) (Includes Myocardial infection, heart attack and unstable angina)
- Sudden death
What is the main cause of coronary heart disease?
The main cause is Atherosclerosis of the coronary artieries.
- Atherosclerosis is a complex inflammatory process initiated due to ‘injury’ or dysfunction of the endothelium.
- This then results in increased permeability to oxidised lipoproteins. These oxidised lipoproteins are taken up by macrophages in cell walls which will then produce lipid-laden foam cells.
- This results in the production of fatty-streaks, which can be seen on the surface of the endothelium under microscopic view.
- This is then followed by migration and proliferation of smooth muscle cells into the intimate of the blood vessels.
- These smooth muscles cells secrete fibrous and protein material like collagen, proteoglycans, elastin and glycoproteins.
- These proteins eventually form a fibrous cap, known as these fatty plaques associated with coronary heart disease.
- As these plaques develop and enlarge, it results in the narrowing of the blood vessels within the heart and reduction in blood flow.
- These fatty plaques can then rupture and a clot will form causing complete blockage.
The development of coronary heart disease is influenced by what risk factors?
Main risk factors:
- Age (non-modifiable)
- Gender (non-modifiable)
- Family history (non-modifiable)
- Smoking
- Diet
- Obesity
- Hypertension
- Hyperlipideamia
Other risk factors:
- Diabetes Mellitus
- Sedentary lifestyle
- Ethnicity
- Excess Alcohol
- Excess Stress
What is the assessment of CV risk used for?
- For primary prevention
- Treat if >10% in there next 10 years
- If already have CVD then assessment not needed, assume high risk and treat
- CV risk assessment is an online tool called QRISK3
What is the pathophysiology of the underlying disease coronary heart disease?
- The chest pain occurs when theres an imbalance between oxygen demand and supply.
- The oxygen demand depends on your heart rate, contractility and systolic wall tension/pressure
- Your oxygen supply depends on your coronary blood flow and oxygen carrying capacity of your blood.
What is stable angina?
Plaques of the atherosclerosis fats have build up on the wall of the blood vessels, which causes narrowing of the diameter and hence reduction in blood supply.
In stable angina the narrowing becomes critical at a certain level of demand from the heart.
=> Ischeamic Chest pain typically provoked by exercise, stress, heavy meals or extremes of temperature, where there is excess demand on the heart and the blood supply is not enough to meet that demand.
=> Stable angina will be relived by rest (hence reducing the demand on the heart) or s/l GTN
Often known as exercise induced angina
- “demand ischaemia”
- Definition: Narrowed coronary arteries unable to meet increased oxygen demand during exercise, stress etc.
What are the clinical symptoms & diagnosis of stable angina?
- Central crushing chest pain
- May radiate to jaw, neck, back or arms
- “Constricting”, “Choking”, “Heavy weight”, or “stabbing”, “burning” or “like a knife”
- Induced by exercise etc & relieved by rest or GTN
- Lack of ECG or cardiac enzymes changes
How can you manage symptom control in stable angina?
Ischaemic chest pain control
- S/L (sublingual) GTN for acute angina
- Where they’ll place a tablet or spray under the tongue which is used to treat attacks of angina. - Antianginal therapy
- Used to prevent attacks in the first place
- 1st line treatment: Beta-blockers, Calcium channel blockers or combination of both
- 2nd line add-ons include: Long acting nitrate, ivabradine, ranolazine or nicorandil
What can you do as secondary prevention in terms of management in stable angina?
- Lifestyle changes
- Smoking
- Weight loss
- Diet
- Exercise - Antiplatelet (aspirin 75mg)
- Statins (Atorvastatin 20mg/80mg)
What is Acute Coronary Syndrome?
Includes:
- Myocardial infarction (MI)
- ST elevated MI (STEMI)
- Non-ST elevated MI (NSTEMI) - Unstable Angina (Troponin Positive ACS)
