Coronary Artery Disease

Coronary Artery Disease

(Ischemic Heart Disease) Bernardo D. Morantte Jr. M.D. Dept. of Medicine College of Medicine Pamantansan Ng Lungsod Ng Maynila

Anatomy of the Coronary Arteries Aorta LCA LMCA

RCA SA nodal artery RV branch

Left anterior descending

Circumflex Septal perforator

Obtuse marginal LV branch

Posterior descending branch

Postero-lateral

Posterior circumflex

Diagonal Bx

Physiology of Coronary Circulation  Myocardial

in diastole

perfusion occurs mainly BP 120/60

Epicardium

Epicardial artery

Subendocardium Endocardium LV LV pressure 120 /10 Diastolic pressure gradient = 50 mm HG < 40 mm mean aortic pressure coronary flow is zero.

Intramural arteries

Regulation of coronary blood flow 

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Aortic driving pressure which is affected by the presence stenosis in the coronary arteries LVED pressure Heart rate and diastolic filling time Coronary vascular resistance _ from the contraction and relaxation of the smooth muscles Endothelium derived vasodilator substance which is affected by the presence of atherosclerosis Myocardial oxygen demand

Types of Coronary artery disease I Congenital  Anomalous origin from the pulmonary artery  Anomalous origin from other coronary arteries  Hypoplastic artery  Myocardial bridging  Coronary AV or sinus fistulas

Anomalous Origin of the Coronary Arteries Aorta LMCA RCA SA nodal artery RV branch

LCA

Left anterior descending

Circumflex Septal perforator

Obtuse marginal LV branch

Posterior descending branch

Postero-lateral

Posterior circumflex

Diagonal Bx

II

Types of coronary artery diseases Continued Atherosclerotic _ most common

III Non- atherosclerotic  Embolus_ atrial fibrillation, endocarditis post cardiac valve replacement, atrial myxoma  Drug induced ex. cocaine  Vasculotides  Kawasaki  Aortic dissection  Iatrogenic

Atheroma

Foam cells Macrophages Plaque

Smooth muscle proliferation and migration Fibroblast calcification Cross section of an artery

Myocardial Bridging Left anterior descending Epicardium

Intramyocardial segment

Endocardium LV

Aortic dissection Aorta

LCA LMCA

RCA SA nodal artery RV branch

Left anterior descending

Circumflex Septal perforator

Obtuse marginal LV branch

Posterior descending branch

Postero-lateral

Posterior circumflex

Diagonal Bx

Myocardial ischemia  Is

the imbalance between the oxygen supply and the myocardial demand for oxygen resulting in some reversible cellular changes in the sarcolema.

Clinical Syndromes of CAD 

Classic angina is chest discomfort resulting from myocardial ischemia due to coronary blood flow insufficiency, related to physical exertion and relieved by rest, maybe associated with transient ST depression in the EKG.

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Variant angina is chest discomfort characteristic of angina occurring at rest associated with transient ST elevation in the EKG.

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Unstable angina_ new onset, prolonged chest pain (20- 30 mins), acceleration of angina, failure to respond to medical therapy.

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Acute MI _ angina like chest discomfort lasting > than 30 mins. associated with sustained EKG changes and enzymatic evidence of myocardial necrosis

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Sudden death syndrome _ sudden cardiovascular collapse with loss of blood pressure and heart beat.

Clinical Syndromes of Coronary artery disease (CAD) Mechanism

(x-area)  Angina spasm

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Chronic stable

Variant angina ( Prinzmetal)

Unstable Angina ( Pre-infarction angina)

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hemorrhage

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Acute MI

> 50 % stenosis coronary

plaque rupture dissection,

non-Q wave MI (subendocardial or non-STEMI) Q wave MI ( transmural or STEMI )

thrombosis total occlusion

sudden death syndrome acute pulmonary edema ( Killip’s class III) cardiogenic shock ( Killips class IV) cardiac rupture

Chest pain EKG

normal Non-cardiac or Angina

ST depression transient angina

persistent Subendocardial infarction

ST elevation transient

persistent

Variant or Prinzmetal

Acute MI

Subacute

old

Risk Factors For CAD Major Hyperlipidemia Hypertension Diabetes mellitus Cigarette smoking Others Obesity Elevated c- reactive protein Physical inactivity Hypothyroidism Positive Family history Acromegaly Hypertriglyceridemia Homocystinemia

Differential Diagnosis of Acute MI 

Does the patient with chest pain need to be in the hospital? Patients with unstable angina and acute MI need to be in the hospital.

Hospitalization  Pulmonary emboli  Aortic dissection  Acute myopericarditis with arrhythmia syndrome)  Serious trauma

Outpatient work-up Acute pericarditis HOCM Prolapse of MV Costochondritis ( Tietze’s Reflux esophagitis / Esophageal spasm Drug induced myocardial ischemia Aortic stenosis Mild chest trauma

Are the diagnostic test you are contemplating available on an outpatient basis?

Diagnostics Chronic stable angina EKG Chest x-ray Exercise testing with or without myocardial perfusion scan Lipid chemistry panel Echocardiogram for those with heart murmur

Diagnostics Unstable Angina • Above test except for exercise testing • Cardiac enzymes CPK isoenzymes Troponin I Persantine technitium or thallium scans Coronary angiogram

Diagnostics 

Acute myocardial infarction EKG Chest x-ray Cardiac enzymes CPK isoenzymnes Troponin I Coronary angiogram if acute intervention is planned Chest CT scan to exclude aortic dissection if suspected.

Risk stratification of CAD Common denominators of patients at high risk for myocardial infarction and sudden death 2. Significant multivessel coronary artery disease 4.

Impaired left ventricular function

Risk Stratification of CAD History High Risk Low Risk 3. Patients with carotid absence artery disease and peripheral vascular disease 7. Exertional angina NYHA class III 9. Prior MI

Risk Stratification of CAD Diagnostics High Risk Treadmill Findings  2 mm of ST depression at low level of exercise  ST segment elevation  Ventricular tachycardia

Myocardial Perfusion scan  Multiple perfusion defects

Low Risk Normal < 2mm of ST depression at high level of exercise

Risk Stratification of CAD Continued Diagnostics High Risk Echocardiography EF < 50% Wall motion abnormalities Radionuclide Left ventriculography Wall motion abnormalities Coronary arteriogram Significant multivessel disease and EF < 50%

Low Risk EF > 50% Normal wall motions Normal wall motion Single vessel disease and normal EF except for LAD

Treatment of Chronic Stable Angina I.

Risk factors modification

III.

Medical Rx A. Nitrites 1. Sublingual nitro – 0.2- 0.6 mg. 2. Nitro spray 3. Oral a. Isosorbide dinitrate 5-20 mg q 4hrs off 8 hours b. Isosorbide mononitrate 20 mg BID 7 hours apart 4. Nitroglycerin ointment ½ inch – 2 inch q 6hrs off at night 5. Nitro patch 0.1 -0.6 mg / hour _ off at night

Treatment of chronic stable angina 

Beta blockers preferably cardioselective Any of the following: a. Metoprolol 25-50mg BID to 400 MG daily b. Atenolol 25 – 100 mg daily c. Acebutalol 200 mg up to 1200 mg ( ISA activity) d. Pindolol 5 mg – 40 mg BID e. Betaxolol 5 mg to 40 mg daily f. Bisoprolol 5- 20 mg daily

K.

Calcium Channel blockers - available in sustained release form a. Diltiazem_ 30 mg TID up to 360 mg / day b. Verapamil _ 80 mg TID : start at 40 mg when EF is low c. Bipridil _ 200- 400 mg.: watch for QT prolongation

d.

Anti-platelet drugs_ Aspirin or clopidogrel

Therapy in Unstable Angina Supportive Rx a) mild sedation b) oxygen for hypoxemia 4. IV nitroglycerin 5. IV Heparin ( UHF) or LMWH 6. Anti-platelet Rx a) ASA b) Abicisimab 0.25 mg/ kg bolus then 0.125 mg / kg for 12 hours 10. Betablockers 11. Anti-arrhythmic therapy for A-fib, SVT and Vtach which may include DC cardioversion 7. Followed by diagnostic work up for risk 1.

Invasive techniques Percutaneous Interventions  Balloon angioplasty (PTCA)  Coronary stent  Atherectomy  Lasers Coronary artery bypass surgery A. Thoracotomy  Saphenous vein grapfts  Internal mammary artery graft  Other arterial conduits B. Closed angioscopically guided bypass surgery

Acute MI I. Window of opportunity: A. Thrombolytic Rx _ 6 hours Any of the following: 1. TPA 100 mg IV in 3 divided doses_ 15 mg IV bolus, then 50 mg over 30 mins. , then 35 mg over 1 hour 2. Reptelase 10 units IV bolus, then 10 units in ½ hour 3. Tenecteplase 40 mg IV bolus single dose 4. IV streptokinase drip B. Primary PTCA or PCI _ 4 hours Maximum benefit is obtained when performed within 1 hour of chest pain

Acute MI I. II.

Medical therapy like unstable angina Ace- inhibitors for ventricular remodeling and CHF

IV.

Hemodynamic monitoring

VI.

Treatment of complications such as arrhythmias

Complications of acute MI and therapy A. B. C. D. E. F. G. H. I.

K. L. M.

Hypotension _ IV inotropic agents: Dobutamine, Dopamine, Amrinone CHF _ IV Furosemide Bradycardia _ atropine or temporary pacemaker Second and third degree AV block_ temporary pacemaker Acute pulmonary edema _ assisted ventilation and IV furosemide Cardiogenic shock _ intra-aortic balloon pump RV infarction _ IV fluids hydration Acute pericarditis / Dressler’s syndrome _ NSAID / Prednisone Ventricular aneurysm and systemic embolization _ IV Heparin followed by Coumadin Rupture papillary muscle acute MR Acute ventricular septal defect (VSD) Cardiac rupture