The cardiovascular system - Coronary artery disease 1 Flashcards
Define the term ‘arteriosclerosis’
A generic term reflecting arterial wall thickening and loss of elasticity
Name 5 major consequences of atherosclerosis
- Sudden death
- MI
- Stroke
- Aortic aneurysm
- Acute ischaemia of the legs and abdominal organs
- Peripheral vascular disease
List the non-modifiable and modifiable risk factors of atherosclerosis
Non-modifiable risk factors
- Increasing age
- Male gender
- Genetic abnormalities
- Family history
Modifiable
- Hyperlipidaemia
- Hypertension
- Cigarette smoking
- Diabetes mellitus
- Inflammation (C-reactive protein)
Describe the pathophysiology of atherosclerosis using the “response to injury” hypothesis
- Endothelial injury
- causes increased vascular permeability
- Causes enhanced leukocyte adhesion/alterred gene expression
- Causes thrombosis - Accumulation of lipoproteins in the vessel wall
- Adhesion of monocytes and platelets
- Factors release
- By activated platelets - Smooth muscle cell proliferation
- causes extra cellular matrix production - Lipid accumulation
- extracellularly and within the cells - Atheroma
Describe the flow pattern in straight regions of arteries and regions of arteries that divide or curve sharply
In straight regions of arteries blood flow is always in the same direction during the cardiac cycle, known as laminar flow pattern
In regions where arteries divide or curve sharply, flow in these regions is slower and can reverse direction during there cardiac cycle, known as oscillatory flow pattern
Describe how endothelial cells in regions of high, laminar shear are protected from athereosclerosis
The endothelial cells have. quiescent, anti-inflammatory phenotype
They are characterised by:
- alignment in the direction flow
- expression of anti-inflammatory genes
- low levels of oxidative cell turn over and permeability
This leads to protection from atherosclerosis
Describe how endothelial cells in regions of disturbed shear are associated with high susceptibility to atherosclerosis
Have an activated, pro-inflammatory phenotype
Characterised by poor alignment, high turnover, oxidative stress and expression of inflammatory genes
This is associated with high susceptibility to atherosclerosis
a) What are fatty streaks?
b) Describe the morphology of fatty streaks
a) Earliest lesions in atherosclerosis
b) Composed of lipid filled macrophages. Not significantly raised and does not cause flow disturbance
Name the 5 most extensively involved vessels in atherosclerosis in descending order
- Lower abdominal aorta
- Coronary arteries
- Popliteal arteries
- Internal carotid arteries
- The vessels of the circle of willis
Describe the morphology of a typical atherosclerotic lesion (from superficial to deep)
- Superficial cap - smooth muscle cells and relatively dense collagen
- Cellular area beneath and to the side of the cap (shoulder) - macrophages, T cells, smooth muscle cells
- Necrotic core deep to the fibres cap - lipid, debris from dead cells, foam cells, fibrin, organised thrombus, and other plasma proteins; the cholesterol crystals “clefts”
- Neovascularization - periphery of the lesions show proliferating small blood vessels
Atherosclerotic plaques are susceptible to several clinically important changes. Name 5 of these changes
- Calcification
- Rupture, ulceration, or erosion
- Haemorrhage into plaque
- Atheroembolism
- Aneurysm formation
Damaged area of MI undergoes progressive sequence of morphologic changes. This can be split into two phases, known as the inflammatory phase and the repetitive & proliferative phase. Describe these two phases
- Inflammatory phase
- 6-12hours : Myocardial infarction - changes of coagulative necrosis
- 1-3 days: acute inflammation (elicited by the necrotic muscle fibres)
- 3 to 7 days : Phagocytosis (Macrophages remove necrotic muscle fibres)
- Reparative & proliferative ophase
- 1-2 weeks: Inflammation resolution, neovascularisation of damaged zone
- By end of week 6: Scar formation, wound healing
a) What is coronary artery disease?
Narrowing of coronary arteries due to atherosclerosis (lipid deposition, inflammation, and thrombosis)
a) List 6 modifiable risk factors of coronary artery disease
b) List 4 non-modifiable risk factors of coronary artery disease
a)
- Smoking
- Hypertension
- Increased cholesterol
- Diabetes
- Obesity
- Poor diet
- Physical inactivity
b)
- Age
- Gender
- Family history
- Ethnicitiy
a) What tool can be used to assess the absolute risk of having an adverse reaction of CVD
b) Where is it commonly used
a) QRISK2
b) Primary care
What are the possible differential diagnosis of recurrent chest pain
Cardiac
- Angina
- Acute coronary syndrome
- Aortic dissection
- Pericarditis
- Valve disease
- Arrythmias
Respiratory
- Pulmonary embolism
- Pneumothorax
- Haemothroax
- Pneumonia
Gastrointestinal
- Oseophagitis
- Oesophageal spasm
- Peptic ulcer disease
- Reflux (GORD)
- Biliary Colic
Musculoskeletal
- Costochondritis
- Cervical radiculitis
- Rib fracture
Neuro
- Herpes zoster
- Depression/anxiety
- Radiculopathy/Myopathy
- MS
What is stable angina?
Angina refers to classic cardiac pain that is felt when there is a reduction in blood flow (ischaemia) through the coronary arteries
Describe the difference between stable and unstable angina
Stable angina
- Refers to pain that occurs predictably with physical or emotional exertion and lasts longer than 10 minutes. It should be relieved within minutes of rest or with medication (e.g., GTN spray)
Unstable angina
- Refers to a sudden new onset of angina or a significant, and abrupt , deterioration in engine that he been stable. Typically relates to pain that increases with frequency or pain that is experienced at rest
What is the aetiology of stable angina?
Primary related to atherosclerosis
Describe the pathophysiology of stable angina
Ischaemia due to a combination of fixed vessel narrowing due to plaque and abnormal vascular tone due to inappropriate vasoconstriction of coronary artery
Describe the presentation of stable angina
3 classic features of angina
- Retrosternal/central chest pain +/- radiation that may involve both chest sides (L.R), arms, neck, lower jaw, upper abdomen
- character: pressure, tightness, or heavy weight. Sometimes “burning”. In neck - “choking”. in the lower jaw - “toothache”
- Last a few minutes - Provoked by physical exertion (especially walking uphill), more easily provoked after heavy meal/cold weather
- Rapid relief (2 mins) by rest or with GTN
What symptoms are non-anginal chest pain?
- Continuous or very prolong pain
- Unrelated to activity
- Bought on by breathing
- Associated with dizziness, palpitations, paraesthesia
What features of a chest pain make it concerning?
- Chest pain lass > 10 minutes
- Chest pain not relieved by two doses of GTN taken 5 minutes apart
- Significant worsening/deterioration in angina (e.g., increased frequency, severity or occurring at rest)
Describe the 5 grades of angina by the Canadian cardiovascular society
Grade I - angina with strenuous activity
Grade II - angina with moderate activity
Grade III - angina with mild exertion
Grade IV - angina at rest
Describe the investigations for stable angina
Basic investigations
- Blood tests
- Resting ECG
- Echocardiography
Diagnostic tests
- 1st line: CT coronary angiogram
- 2nd line: functional test e.g., exercise ECG, myocardial perfusion imaging with SPECT, Dobutamine stress echo, stress MRI
- 3rd line: coronary angiogram (invasive)
a) When should you offer anatomical non-invasive testing (e.g.,CT coronary angiography)
b) When should non-invasive function testing be offered (e.g., stress echo)
c) When should you offer anatomical invasive testing (coronary angiography)
a)
- Low clinical likelihood of CAD
- No history of CAD
b)
- High clinical likelihood of CAD
- Revascularisation therapy likely needed
- Established CAD
c)
- High clinical likelihood of CAD and symptoms unresponsive to medical therapy
- Typical angina at low activity level and high risk of cardiac event
- Left ventricle dysfunction on ECHO suspected secondary to CAD