PATHOGENISIS OF CORONARY ARTERY DISEASE

1. PATHOGENISIS OF CORONARY ARTERY DISEASE LECTURE 2 Dr. Zahoor Ali Shaikh

2. 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.

3. 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.

4. 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

5. PATHOGENISIS OF CORONARY ARTERY DISEASE 2. Life style - Factors can be modified such as - obesity - hypertension - hyperlipidaemia - diabetes mellitus - cigarette smoking

6. PATHOGENISIS OF CORONARY ARTERY DISEASE

7. PATHOGENISIS OF CORONARY ARTERY DISEASE • We will see the normal structure of artery and development of atherosclerosis.

8. NORMAL STRUCTURE OF ARTERY

9. TYPES OF LIPOPROTEINS

10. 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

11. Development of Atherosclerosis

12. PATHOGENISIS OF CORONARY ARTERY DISEASE

13. PATHOGENISIS OF CORONARY ARTERY DISEASE What is Atherosclerotic plaque? • Atherosclerotic plaque consist of aggregation of smooth muscle cells, macrophages, leukocytes, collagen and lipids

14. PATHOGENISIS OF CORONARY ARTERY DISEASE Site of atherosclerosis

15. CORONARY ARTERY DISEASE

16. 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

17. 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

18. 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.

20. CHRONIC ISCHEMIC HEART DISEASE • Coronary Artery Disease – two types 1. Chronic Stable Angina 2. Variant or Vasospastic Angina also called prinzmetal Angina

21. 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.

22. 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

24. 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

25. 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 .

26. 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

27. 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

28. CHRONIC ISCHEMIC HEART DISEASE Treatment • Non-pharmacological • Pharmacological • Coronary intervention

29. 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

30. CHRONIC ISCHEMIC HEART DISEASE Treatment • Pharmacological • Nitrates • Beta-blockers • Calcium channel blockers • Aspirin

31. 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

32. 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

34. 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

35. ACUTE CORONARY SYNDROME [ACS] IMPORTANT • Troponin I and Troponin T are the most sensitive and highly specific for myocardial infarction

36. 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

37. 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

38. 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.

39. 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.

40. 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

41. 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.

43. 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

45. THANK YOU