Atheroma formation Flashcards
Un-modifiable risk factors for atheroma
- Age increases risk
- Gender - M>F low oestrogen, post menopause
- Ethnicity - asians are at greater risk of heart disease, Afro-Caribbean’s have higher risk of hypertension
- Genetics - fibrinogen (clotting factor disorders), lipid disorders, unlikely to be single gene disorders
Modifiable risk factors for atheroma
- Obesity
- Raised cholesterol
- Smoking
- Hypertension
- Physical inactivity
- Metabolic syndrome (diabetes, high BP, obesity)
- Hyperglycaemia
Pathogenesis of atheroma
- LDL accumulates under artery endothelium and oxidises
- Macrophages and T cells influx
- Local irritation - macrophages die and this triggers smooth muscle proliferation and collagen deposition (artery tries to heal)
- Activates clotting cascade
- Thrombus forms - breaks off to form embolus
Occlusion of carotid artery
Stroke
Occlusion of coronary artery
MI
NSTEMI
Non-ST elevated MI
Acute coronary syndrome
Sudden reduced blood supply
- NSTEMI (non-ST segment elevated MI)
- STEMI (ST elevated MI)
- Unstable angina
Cardiac ischaemia
Left anterior descending artery supplies LV
What is angina?
Blood can get down coronary artery but can’t increase blood supply when needed = pain
Sx of coronary thrombosis
sudden onset left sided chest pain radiating to right arm, sweating, shortness of breath, aspirin 300mg given, arm pain on climbing stairs = coronary thrombosis
Treatment for STEMI
aspirin 300mg then 75mg for life, prasugrel (P2Y12 inhibitor) and aspirin, heparin, stent, immediate percutaneous coronary intervention (coronary arteries reopened)
What is PCI?
Wire passed into coronary artery, balloon inflated, stent deployed to keep artery open
NSTEMI on ECG
T wave inversion
ST complex flat
how to diagnose NSTEMI
Blood test for troponin T
MI on blood test
Troponin T and I
How to differentiate between NSTEMI and unstable angina by blood test
NSTEMI = troponin rise but angina means none
sx unstable plaque
chest pain at rest, intermittent, often reduced exercise tolerance
Treatment NSTEMI low risk
300mg aspirin and 75mg/day for life, ticagrelor, clopidogrel if high bleeding risk
Treatment NSTEMI high risk
angiography within 72h, stent, heparin, prasugrel or ticagrelor with aspirin
Glycoprotein iib/iiia
Glycoprotein iib/iiia inhibitors stops pathway, blocks integrin receptor for fibrinogen by inhibiting fibrinogen bridges, used when patient receiving PCI - abciximab, tirofiban
Stabilising coronary plaque
- Reduce vulnerability of people by managing risk factors (cholesterol by statins, control BP, quit smoking)
- Reduce risk of thrombosis = antithrombotic drugs, need to compare bleeding risks for other agents
Post STEMI treatment
Antiplatelets:
- Aspirin
- Clopidogrel - maintain stent patency
- Beta blocker - bisoprolol
- ACEi - rampiril
- Statin for all pts with coronary disease - atorvastatin
- GI protection - lansoprazole
Stents
Maintains lumen in coronary artery - nickel-titanium alloy
Drug eluting stents in majority of small vessels or long lesions (sirolimus or paclitaxel are expensive)
Stent restenosis
Stent can cause further aggregation of collagen
Requires subsequent PCIs
Siroliumus and paclitaxol
- Anti-proliferative and immunomodulatory 0 angiographic restenosis in <5%
- Effects: non specific with respect to cell type
- Endothelium may never recover
- Wall may recede from stent (positive remodelling) leaving stent struts mal-apposed
Stent thrombosis
- Iatrogenic
- Avoided by good technique and anti-platelet drugs
- Aspirin for life and clopidogrel for up to a year
Widowmaker’s lesion
L main artery - more common in men, high risk of death
