CVS Diseases Flashcards
What is Atherosclerosis?
- Arteriosclerosis= Atherosclerosis + Arteriolosclerosis
- Multifactorial inflammatory disease of the tunica intima
- Buildup of cholesterol plaques in the intima
- Cholesterol +WBC
- M>F
What are the common sites for arteriosclerosis?
: Abdo CramP:
Abdominal artery> Coronary> Popliteal> Carotid> Circle of Willis
What are the modifiable and nonmodifiable atherosclerosis?
Modifiable
- Smoking
- DM
- HTN
- Dyslipidemia
- Alcohol
Nonmodifiable
- FH
- Age: M>45, F>55
- Postmenopausal females
Basic principkes of atherosclerosis
- NO> vasodilation via activation of eNOS -> stimulation of guanylate cyclase and cGMP production-> decreasing intracellular Ca2+ decreasing myocyte excitation and contraction.
- LDL: transports cholesterol and Ca2+ INTO cell
- HDL: transports cholesterol and Ca2+ OUT of cell
- In ACS: Adenosine is released by ischaemic myocardium through A1 receptors->angina-> PAIN
Atherosclerosis
Stage 1
- Endothelium becomes dysfunctional
- Cause: Chronic stress due to smoking, high BP, hyperlipidemia
- Chronic stress causes damage to the glycocalyx barrier which monitors the shear forces in the blood vessels
- Permanent hyperglycaemia can destroy the glycocalyx. Regeneration takes 12 hrs.
- Glycocalyx dysfunction-> leaky vessel
Atherosclerosis
Stage 2
- Endothelial damage-> LDL enters
- Excess LDL-> increases permeability of cells to enter the intimal layer-> monocytes enter
- Monocytes enter through diapedesis
- LDL oxidizes and inactivates NO!
- NO loses its vasoprotective effect
•-> ACCUMULATION OF MACROPHAGES + oxLDL
Atherosclerosis
Stage 3
- oxLDL releases cholesterol
- Monocytes engulf cholesterol-> die off and form foam cells
- Accumulation of foam cells-> fatty streak
Atherosclerosis
Stage 4
- Fatty streak is thrombogenic-> platelets adhesion -> PDGF, PGF, TGF-B secretion -> SMC proliferation and migration of SMC from tunica media into tunica intima
- SMC + macrophages secrete ECM ( elastin, collagen, proteoglycan)-> form a wall around the fatty streak to prevent clotting-> fibrous cap
- LDL-> calcium depostion
- Endothelial cell injury prevents HDL from removing the calcium-> stiff fibrous cap
Atherosclerosis
Stage 5
- Atheroma is formed
- Grows
- **The thinner the fibrous cap, the higher risk of thrombus**
Atherosclerosis
Stage 6
- BURST:
- Foam cells undergo necrosis-> release of MMPs
- IFN-γ induces macrophage MMP expression-> weakening of cap
- IFN-γ inhibits VSMC proliferation and collagen synthesis-> weakening of cap
- Plaque rupture-> exposure of underlying-> thrombus formation
Complications of atherosclerosis
•Obstruction:
- 40% luminal obstruction: maximal flow during exercise maintained
- >50% -> coronary ischemia
- > 70/75% lumen occluded prior to onset of symptoms -> Downstream cellular injury/death
- Coronary arteries-> Angina+ ACS
- Internal carotid+ Middle cerebral-> Stroke + cerebral artery
- Mesenteric arteries-> acute/chronic mesenteric ischemia
- Popliteal artery-> peripheral ischemia ( gangrene + claudication)
- Renal artery-> Hypertension ( activation of RAAS)
- Weakening of vessel wall-> Abdominal aortic aneurysm below L2 ( no vaso vasorum) -> hemorrhaging
- Thromboembolism, Cholesterol emboli-> livedo reticularis, AKI, gangrene
Investigations for athersclerosis
•Bloods:
- Lipid profile: TC, LDL, HDL, triglycerides
- Fasting glucose
- FBC
- Creatinine
- Myocardial damage markers: troponins, CK-MB ( ACS suspected)
- Homocysteine
- HbA1c
- BNP
- Thyroid fxn
- ECG-> ACS, underlying hypertrophy
- Stress testing unless contraindicated
- Echo-> Valvular heart disease, HF
- CT-> extent of calcification
- Coronary angiography
Treatment for Atherosclerosis
Lifestyle:
- Smoking cessation
- Weight loss
Underlying comorbidity managed- HTN, DM
•DM and renal disease treatment goal of BP< 130/80 mmHg
Medical:
- Low dose aspirin, clopidogrel
- Statin therapy
What is CAD?
Coronary Artery Disease
- Disease due to imbalance between myocardial oxygen demand and supply from coronary arteries
- Reduced O2 supply to the heart is defined as myocardial ischemia-> reduced ability of heart to contract
- If prolonged ischemia -> myocardial infarction
What causes CAD?
- Atherosclerosis**
- Coronary artery embolus: FAT BAT. Classic triad of fat emboli?
- Vasculitis
- Vasospasm
- Aortic stenosis
Presentations for CAD
Stable angina, Prinzmetal angina, ACS, sudden cardiac death
What is Stable Angina
- Myocardial ischemia due to a plaque occluding >75% of the coronary artery lumen.
- Relieved by rest, nitroglycerin/GTN spray
Clinical Features of stable angina
- Deep/poorly localized pain
- Squeezing/ crushing/suffocating retrosternal pain
- Radiates to the arm, jaw, neck
- SOB, nausea, vomiting, diaphoresis, fatigue, dizziness
Investigations of stable angina?
•ECG normal, troponins normal, cardiac stress test +
A plaque can cause near-total occlusion of the CA but individuals may not develop an infarction-
TRUE/FALSE
TRUE- this is called a collateral circulation
what is the criteria for stable angina?
- Substernal chest discomfort
- Provoked by exertion, stress
- Relieved by GTN, rest
- If all three met-> typical angina
- If 2-> atypical angina
- If 0,1-> non-cardiac chest pain
What is prinzmetal angina?
- vasospasm of a large coronary artery
- Transmural ischemia, rest pain, more prolonged than classic angina
- ECG: ST elevation
- Troponins normal
- Women <50
What triggers prinzmetal angina?
- Smoking
- Electrolyte disturbance
- Cocaine
- Cold stimulation
Other angina variants:
Angina equivalent syndrome, syndrome X, silent ischemia, nocturnal
What is ACS
Acute Coronary Syndrome = plaque disrupted
Involves: Unstable angina, NSTEMI, STEMI
Clinical features of ACS
- New- onset angina
- Acute retrosternal chest pain
- Dull/ squeezing/ crushing/ tightness
- Radiation to neck, arm, shoulder, epigastrium
- Dyspnea
- Pallor
- Nausea, vomiting
- Diaphoresis
- Dizziness, lightheadedness, syncope
- Silent MI?
What are the signs for cardiac shock?
- Tachy/bradycardia
- Hypotension
- Raised JVP
- Murmur due to arrhythmias
- Cold extremities
ACSyndrome is classed by:
Defined as 2 out of 3:
- Unstable, ischaemic chest pain
- Ischaemic ECG changes
- Raised cardiac biomarkers
Comparisons Unstable angina, NSTEMI, STEMI
What is digoxin used for?
Digoxin is a type of medicine called a cardiac glycoside. It’s used to control some heart problems, such as irregular heartbeats (arrhythmias) including atrial fibrillation. It can also help to manage the symptoms of heart failure, usually with other medicines. Digoxin is only available on prescription
What is the thinking you do if a patient has chest pain?