Coronary Circulation + Coronary Artery Disease/MI

The Coronary Circulation

Blood vessels that supply and drain the heart

Coronary Arteries deliver oxygenated blood to the coronary capillary beds and

Coronary Veins drain deoxygenated blood from the capillaries

Right and Left Coronary Arteries

branch from the ascending aorta and travel in the right and left atrioventricular sulci, respectively

Right Coronary Artery

Branches and supplies the right atrium and ventricle with the Marginal Artery and the Posterior Interventricular Artery

Left Coronary Artery

Branches into Anterior Interventricular Artery (Left Anterior Descending Artery, or LAD) that supplies the interventricular septum, most of the anterior left ventricle, and some of the posterior left ventricle

Circumflex Artery that supplies the left atrium and parts of the left ventricle

In some people, it replaces the right coronary artery in supplying the branch that becomes the posterior interventricular artery

Percutaneous Coronary Angiography

Arteries can be imaged with Percutaneous Coronary Angiography

A small tube is fed through the systemic circuit and a dye is injected producing an image

Coronary (Cardiac) Veins

coronary sinus, great cardiac vein, small cardiac vein, middle cardiac vein

Coronary Sinus

A large venous structure on the posterior heart that drains into the right atrium

Receives blood from:

Great Cardiac Vein which drains the left atrium and much of both ventricles

Small Cardiac Vein which drains the right atrium and parts of the right ventricle

Middle Cardiac Vein which drains mostly the posterior left ventricle

Anastomoses

Systems of channels formed between blood vessels

may form between coronary arteries or with arteries outside the coronary circulation

In arteries, may form to provide Collateral Circulation, or alternate routes of blood flow, if blood flow to the myocardium is insufficient

Coronary Artery Disease (CAD)

leading cause of death worldwide

Results from a buildup of fatty Plaques in the coronary arteries that decrease blood flow to the myocardium, leading to Myocardial Ischemia, or decreased oxygenation

Symptoms often include Angina Pectoris, or chest pain

Myocardial Infarction (MI)

Myocardial Infarction (MI), or Heart Attack results if plaques rupture and a clot forms that obstructs blood flow resulting in death of the myocardium

Symptoms and Risk Factors of MI

Symptoms of an MI include radiating chest pains along the dermatomes to the left arm or left side of the neck, shortness of breath, sweating, anxiety, nausea and/or vomiting

women may not present with chest pain

Survival depends on the extent of damage as cardiac muscle cells do not undergo mitosis

Risk factors include smoking, high blood pressure, poorly controlled diabetes, high levels of certain lipids in the blood, obesity, age over 40 for males and over 50 for females, genetics, and male sex

Treatment of Coronary Artery Disease

Initial treatments involve lifestyle modifications and appropriate medications

Coronary Angioplasty—A balloon is inflated in the blocked artery and a wire-mesh tubing called a Stent is inserted to keep the artery open.

Coronary Artery Bypass Grafting—Other vessels are grafted onto the diseased coronary artery to bypass the blockage and provide an alternate route for blood flow.