Atheroma, Infarction, Preventation Flashcards
Key components of atheromatous plaques?
Necrotic core (inner)
Cellular layer
Fibrous cap
Components of necrotic core?
dead cellular tissue, lipid, cholesterol clefts, fibrin, foam cells, cell debris
Where does the necrotic core lie?
between media+intima
Components of cellular layer?
foam cells, migrating SM cells, macrophages, lymphocytes, less connective tissue
Components of fibrous cap?
SM cells + collagen
Where does the fibrous cap lie?
below endothelium if stable plaque
Stages of atheromatous plaques?
- initial lesion
- fatty streak
- intermediate lesion
- atheroma
- fibroatheroma
- complicated lesion
What’s initial lesion
- isolated foam cells
- macrophage infiltration in intima builds up
- lipid accumulation
- fatty streak
How does fatty streak grow?
from intracellular lipid accumulation
What’s intermediate lesion
intracellular lipid accumulation
small intracellular lipid pools
Describe atheroma
intracellular lipid accumulation
core of extracellular lipid
Describe fibroatheroma
single/multiple lipid cores
calcified
How does fibroatheroma grow?
increased SM + collagen
What’s complicated lesion
surface defect
hematoma-haemorrhage
thrombosis
How does complicated lesion grow?
hematoma/thrombosis
At 20 what’s the sig coronary atherosclerosis?
20%
At 20-29 what’s the sig coronary atherosclerosis?
50%
At 30-39 what’s the sig coronary atherosclerosis?
65%
Common sites of plaque build up?
Circle of Willis Carotid arteries Coronary arteries Aorta Iliac arteries
Major risk factors for atherosclerosis?
Age, genetics 🚬🥤💊🍔 Male + menopausal women Hyperlipidaemia Hypertension Diabetes mellitus Metabolic syndrome Systemic inflammation promotes atheroma eg rheumatoid arthritis + parasitic infections
eg of inflammatory mediators (IM)?
LDL + Angiotension II
Describe initiation
- oxidised LDL + angiotension II is an inflammatory mediator
- inflammation
- activates endothelial releases cytokines + adhesion molecules
- circulating monocyte lodges to endothelial cell
- monocyte moves into intima
- monocyte differentiates into tissue macrophage
Describe plaque formation
- tissue macrophage takes up LDL
- becomes foam cell
- releases IM
- SM cells migrates into intima + profilerates
- releases elastic + collagen
Describe maturation of plaque
- SM + foam cell becomes apoptotic
- releases lipid forms necrotic core
- matrix breakdown forms fibrous cap
Describe calcification + instability of plaque
- foam cells release calcium deposits
- unstabilises plaque
Describe rupture of plaque
- endothelial breaks
- vWf exposed to active platelets + TF activates coagulation cascade
- thrombosis in coronary artery
- MI
Describe rupture of plaque
- endothelial breaks
- vWf exposed to active platelets + TF activates coagulation cascade
- thrombosis in coronary artery
What’s occlusive thrombosis + eg?
blocks artery eg MI
What’s thromboembolism + eg?
thrombus moves eg ischaemic stroke
What’s peripheral vascular disease + eg?
less blood flow to legs so wounds don’t heal eg critical limb ischaemia
What’s aneurysm + eg?
wall weakness eg AAA
Causes of chest pain?
Broken rib Collapsed lung Nerve infection (shingles) “Pulled” muscle Infection Heart burn (hernia) Pericarditis Blood clot in the lungs (PE) Angina MI
What’s stable cardiac angina?
atheroma which permanently limits blood flow
What’s unstable cardiac angina?
transient thrombosis where rupture causes thrombosis which is cleaned up by fibrolytic system
What’s MI?
COMPLETE blockage of coronary artery
ECG of MI?
ST elevation
Why are there elevated cardiac troponins released during MI?
necrosis
Treatment of Acute Coronary Syndromes?
PHARMACOLOGICAL: General myocardial oxygenation Antiplatelet/Antithrombotic Analgesia Myocardial energy consumption Coronary vasodilatation Anticoagulation Thrombolysis Plaque stabilization SURGERY: Reperfusion Re-vascularisation
Time frames for Acute Coronary Syndromes treatment?
Arrival to ECG: 10 min
Door-to-needle for thrombolysis: 20 min
Door-to-balloon time for PCI: 60 min
Treatment of MI?
SURGERY: Balloon angioplasty Stent Coronary bypass PHARMACOLOGICAL
What are the pharmacological treatments for MI + ischaemic stroke?
tPA + bacterial activator, streptokinase for therapeutic thrombolysis
Describe how tPA works?
- allows plasminogen -> plasmin
- lyse fibrin to get D dimers
How are D dimers generated?
when cross-linked fibrin is degraded
How are FDP (Fibrin degradation products) generated?
when non-cross linked fibrin or fibrinogen is broken down
Complications of MI?
Acute pump failure Conduction problems – arrhythmia Papillary damage – valve dysfunction Mural thrombosis - stroke Wall rupture Chronic pump failure – myocardial fibrosis/scarring
Long term management after MI?
❌🚬 🏃♂️ Diabetes management ❌🍔 Blood pressure control Lipid management Management of heart failure or LV dysfunction Prevention of sudden death
eg of CVD?
coronary heart disease (CHD) cerebrovascular disease peripheral arterial disease rheumatic and congenital heart diseases venous thromboembolism lymphatic disease
CVD mortality in men vs women?
men: 25%
women: 17%
Define primary prevention
lowering the risk of disease occurring
Define secondary prevention
lowering the risk of disease recurring
Where does 80% CVD mortality occur?
in developing nations
Why’s CVD worldwide predicted to increase?
as the prevalence of risk factors rises in previously low-risk countries
What does primary prevention prevent?
- risk factors
- oxidative + mechanical stress + inflammation
- early tissue dysfunction
- atherothrombosis + progresive CVD
- MI, stroke, renal/peripheral arterial insufficeincy
What does secondary prevention prevent?
- MI, stroke, renal/peripheral arterial insufficeincy
- pathological remodelling
- target organ damage
- end-organ failure
- death
Where’s early deaths from CVD (<75) most common?
north England, central Scotland, south Wales
Where’s highest rate of CVD decline?
deprivation from low socioeconomic communities
Direct healthcare costs of CVD per year?
£9 billion
CVD cost to the UK economy per year (including premature death, disability, informal costs) ?
£19 billion
How much MI is preventable?
90%
Risk factors of CVD?
🚬
Abnormal lipid profile (apolipoprotein ratio apoB/apoA-I)
Hypertension
Diabetes mellitus
Abdominal obesity (abdominal fat is a stronger predictor than BMI)
Psychosocial (stress)
Protective factors of CVD?
Regular 🍎 + 🥦
🏃♂️
Moderate 🥤
Non-modifiable risks of CVD?
Age – risk of stroke doubles every decade after 55
Family history – direct blood relative has CHD or stroke before age 55 (65 for female). INTERHEART study says 10% of risk accounted by family history
Ethnicity – Pakistan, Bangladesh, Indian, African Caribbean
Management of CVD?
❌🚬 🏃♂️ Diet + weight reduction Lipid management BP control Diabetes management
Dietary targets to prevent CVD?
- 🍎🥦🥜 2-3 servings daily
- ↓saturated FA, <10% of total energy via replacement by poly-unsaturated FA (PUFA).
- Use vegetable oils rich in PUFA + spreads (soybean, canola, extra-virgin olive oil)
- ↓refined grains + sugar 30-45 g wholegrain products fibre daily
- 1-2 servings oily 🐟 weekly (sardines, herring, tuna, salmon, mackerel, trout)
- ❌processed meat, ↓fresh red meat to 2-3 servings weekly
- ❌ trans unsaturated FA
- ❌coke
- ↓sodium <5 gr of salt daily
- 🥤2 glasses daily (20 gr alcohol) in men + 1 glass daily (10 gr alcohol) in women.
Consequences of improving lipid profiles by daily statins?
Cost – feasible at a population level?
Distract from simpler ways to lower lipids (diet/exercise)?
Compliance – would people adopt this approach of chronic drug administration?
When is drug treatment for hypertension used?
systolic pressure above 160 /diastolic above 100 mmHg
Link between diabetes + CVD risk?
Risk from diabetes is as great as having previous history of CVD
2 approaches to primary prevention?
Individual: clinician tailors care to individual patient needs + risk factors
Population: increased public awareness - or law used to reduce risk factors
How each approach of primary prevention contributes to decline in UK CHD events?
42% of decline from interventional approaches (both primary and secondary)
58% from population-level approaches influencing smoking + hypertension
Issues with secondary prevention + eg?
failure of the medical profession to engage with patients
eg 1 in 7 patients were advised to attend smoking cessation clinics
What does class I level A mean + eg?
benefit»_space;> risk with large studies
Dietary interventions to lower LDL-C + lower BP
What does class IIb level B mean + eg?
no benefit/harm with single studies
HbA1C testing of asymptomatic patients w/o diagnosis of diabetes + genomic testing