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PATHOGENISIS OF CORONARY ARTERY DISEASE
LECTURE 2Dr. Zahoor Ali Shaikh
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PATHOGENISIS OF CORONARY ARTERY DISEASE
Atherosclerosis is most common cause of coronary artery disease (CAD).
Atherosclerosis can affect one or all three major coronary arteries i.e. LAD, Left circumflex, right coronary artery.
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PATHOGENISIS OF CORONARY ARTERY DISEASE
What is Atherosclerosis? It is type of arteriosclerosis or
hardening of arteries. In Atherosclerosis, there is formation
of fibro fatty lesions in the intimal lining of the large and medium sized arteries such as aorta and its branches, coronary arteries and cerebral arteries.
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PATHOGENISIS OF CORONARY ARTERY DISEASE
Major risk factor is hypercholesteremia. Hypercholesteremia can be due to 1. Constitutional factors 2. Life style
1. Constitutional factors (can not be changed) such as
- increasing age - male gender - family history of premature coronary artery
disease
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PATHOGENISIS OF CORONARY ARTERY DISEASE
2. Life style - Factors can be modified such as
- obesity - hypertension - hyperlipidaemia - diabetes mellitus - cigarette smoking
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PATHOGENISIS OF CORONARY ARTERY DISEASE
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PATHOGENISIS OF CORONARY ARTERY DISEASE
We will see the normal structure of artery and development of atherosclerosis.
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NORMAL STRUCTURE OF ARTERY
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TYPES OF LIPOPROTEINS
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PATHOGENISIS OF CORONARY ARTERY DISEASE
Development of atherosclerotic lesion is a progressive process involving
1. Endothelial cell injury 2. Migration of inflammatory cells 3. Smooth muscle proliferation and
lipid deposition 4. Development of atheromatous
plaque with a lipid core
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Development of Atherosclerosis
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PATHOGENISIS OF CORONARY ARTERY DISEASE
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PATHOGENISIS OF CORONARY ARTERY DISEASE
What is Atherosclerotic plaque? Atherosclerotic plaque consist of
aggregation of smooth muscle cells, macrophages, leukocytes, collagen and lipids
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PATHOGENISIS OF CORONARY ARTERY DISEASE
Site of atherosclerosis
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CORONARY ARTERY DISEASE
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CORONARY ARTERY DISEASE
It is divided into 1. Chronic ischemic heart disease i. Chronic Stable Angina ii. Variant or Vasospastic Angina also called prinzmetal Angina 2. Acute coronary syndrome i. Unstable angina ii. Myocardial infarction
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ATHEROSCLEROTIC LESIONS IN CORONARY ARTERIES
These maybe 1. Stable or fixed plaque – causes
stable angina 2. Unstable plaque – which can
rupture and can cause platelet adhesion and thrombus formation and can cause unstable angina and myocardial infarction
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UNSTABLE PLAQUE
Why plaque rupture occurs? It maybe spontaneous or triggered by
change in blood flow and vessel tension due to
- sympathetic activity - increased BP - heart rate - force of cardiac contraction These factors may disrupt the plaque.
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CHRONIC ISCHEMIC HEART DISEASE
Coronary Artery Disease – two types 1. Chronic Stable Angina 2. Variant or Vasospastic Angina also
called prinzmetal Angina
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1- Chronic Stable Angina
There is chest pain or pressure sensation or discomfort due to transient myocardial ischemia.
Pain in angina is usually described as constricting, squeezing or suffocating sensation.
Pain is located in sub-sternal area or pre-cordial area of chest.
Pain may radiate to left shoulder, jaw, left arm (inner side) or epigastric region.
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1- Chronic Stable Angina
Pain is associated with fixed coronary obstruction, usually pathology is atherosclerosis.
Stable Angina is provoked by exercise, emotional stress and is relieved within minutes (5-10mins) by rest or use of nitroglycerine sublingually.
Precipitating factors for pain - physical exertion - exposure to cold - emotional stress
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2- VARIANT OR VASOSPASTIC OR PRINZMETAL ANGINA
Variant angina is due to spasm of coronary artery.
Cause is not completely understood but maybe due to
- Endothelial dysfunction - Hyperactive sympathetic response - Defective handling of Calcium by
vascular smooth muscle - Altered Nitric acid production
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2- VARIANT OR VASOSPASTIC OR PRINZMETAL ANGINA
Variant Angina occurs at rest or with minimal exercise (stable angina occurs at exercise).
ECG shows Transient ST-elevation .
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CHRONIC ISCHEMIC HEART DISEASE
Diagnosis and Treatment Take detail history of pain (rule out non
coronary causes e.g. esophageal reflux or musculo skeletal disorder)
Look for risk factors e.g. hypertension, DM, obesity, hyperlipidemia, smoking
Laboratory test - Noninvasive studies - Invasive studies
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CHRONIC ISCHEMIC HEART DISEASE
Noninvasive Test ECG X-ray chest Exercise stress test Echo cardiography Nuclear imaging studies CT and MRI
Invasive Test Coronary Arteriography
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CHRONIC ISCHEMIC HEART DISEASE
Treatment1. Non-pharmacological 2. Pharmacological 3. Coronary intervention
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CHRONIC ISCHEMIC HEART DISEASE
Treatment- Non-pharmacological Life style modification Stop smoking Stress reduction Regular exercise Weight reduction if obesity Decrease dietary intake of cholesterol Avoid cold (it produces vasoconstriction) If angina – sit down and rest
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CHRONIC ISCHEMIC HEART DISEASE
Treatment- Pharmacological Nitrates Beta-blockers Calcium channel blockers Aspirin
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CHRONIC ISCHEMIC HEART DISEASE
Treatment- Coronary intervention PCI – Percutaneous Coronary Intervention i.e. -Angioplasty -Stent- Surgery Coronary artery bypass graft (CABG) Surgery is indicated in patient with double or triple vessel disease
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II. ACUTE CORONARY SYNDROME [ACS]
ACS includes 1- unstable angina 2- acute myocardial infarction - acute MI may be NSTEMI or STEMI - ACS is classified based on presence or absence of ST-segment changes on the ECG
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ACUTE CORONARY SYNDROME [ACS]
- Serum biomarkers are used to determine whether Myocardial infarction has occured - Serum makers done in ACS are -- Cardiac Troponin I [TnI] & Troponin T
(TnT) -- Myoglobin -- Creatinine Kinase MB (CK-MB)- As myocardial cell become necrotic in MI,
their intracellular content diffuse in interstial fluid and blood
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ACUTE CORONARY SYNDROME [ACS]
IMPORTANT
Troponin I and Troponin T are the most sensitive and highly specific for myocardial infarction
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UNSTABLE ANGINA
Pain in unstable angina occurs at rest or with minimal exertion
Pain lasts for more than 20mins Unstable angina is risk for MI Serum markers are not increased
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MYOCARDIAL INFARCTION [MI]
MI is also known heart attack. There is ischemic death of myocardial
tissue. ECG shows ST-elevation Area affected depends on which
coronary artery is blocked
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MYOCARDIAL INFARCTION [MI]
Clinical Presentation Chest pain which is sudden and severe,
retrosternal Character of pain – crushing,
constricting, suffocating or as some one sitting on the chest
Pain is retrosternal but may radiate to left arm (inner side), neck, or jaw or epigastrium.
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MYOCARDIAL INFARCTION [MI]
Pain and sympathetic stimulation combine to give rise to tachycardia, anxiety, restlessness
Sudden death can occur in Acute MI, within one hour of symptoms
Cause of death ventricular fibrillation, ventricle pump failure.
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TREATMENT IN ACUTE CORONARY SYNDROME
Relieve pain e.g. Morphine ECG 12 lead – also monitor ECG Oxygen Aspirin – anti-platelet Nitrates - vasodilator Anti-coagulent ACE I
IMPORTANT Look for candidates for reperfusion therapy
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PERCUTANEUS CORONARY INTERVENTION
It includes PERCUTANEUS TRANSLUMINAL CORONARY ANGIOPLASTY (PTCA) with inflatable balloon.
Stent implantation Stents are of two types - Non-drug eluting - Drug eluting – they provide delivery of
anti-platelet agents and decrease the risk of restenosis and their results are better than Non- drug eluting stents.
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CORONARY ARTERY BYPASS SURGERY (CABG)
Surgery is done to bypass the obstructed coronary blood vessel.
Graft are used from 1. Saphenous vein 2. Internal Mammary artery
NOTE – Surgery is done for patients with coronary artery disease who do not respond to medical treatment or not suitable for PCI
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