Coronary Artery Disease

Coronary Artery Disease

Concept:

Coronary artery disease (CAD) is a common disease, especially in developed countries. The main cause is the deposition of fat in the inner layer of the coronary arteries (CA), leading to atherosclerosis. The process of atherosclerosis progresses gradually, causing narrowing of the CA lumen and the formation of blood clots, leading to blockage of blood vessels.

Complications:

The main complications of CAD are angina, myocardial infarction (MI), and sudden death.

Causes:

• Coronary artery disease:

• Atherosclerosis: the main cause, accounting for the majority of cases.

• Coronary spasm: occurs when the CA is abnormally constricted, unrelated to atherosclerosis.

• Vasculitis: rarer, caused by inflammation that damages the CA.

• Valvular heart disease:

• Aortic valve disease: aortic stenosis or insufficiency, often due to atherosclerosis or syphilis.

• Hypertrophic cardiomyopathy: the heart muscle thickens, reducing pumping function, leading to myocardial ischemia.

Pathophysiology:

• Angina: The heart’s oxygen demand exceeds the supply capacity of the coronary system. Pain is a direct manifestation of local myocardial ischemia and the accumulation of metabolic products due to oxygen deficiency.

• Factors determining myocardial oxygen consumption:

• Heart rate

• Myocardial contractility

• Systolic blood pressure

• Coronary reserve: The ability of the heart to increase coronary blood flow when oxygen demand increases.

• Vasomotor capacity of the CA: The ability of the CA to dilate to regulate the amount of blood supplied to the heart.

• Myocardial ischemia:

• Secondary ischemia: increased oxygen demand.

• Primary ischemia: sudden decrease in coronary blood flow.

Related Pathophysiology:

• Heart and oxygen: The heart needs oxygen to function.

• Coronary reserve: The heart’s ability to increase coronary blood flow when oxygen demand increases.

• Vasomotor capacity of the CA: The ability of the CA to dilate to regulate the amount of blood supplied to the heart.

• Myocardial ischemia: localized ischemia due to reduced coronary blood flow or increased oxygen demand.

Angina:

• Typical angina: chest pain after exertion, radiating to the inner left arm, lasting a few minutes, relieved by rest or vasodilator medication.

• Atypical angina: unclear symptoms, can occur at rest or during sleep.

Myocardial infarction:

• MI: heart muscle necrosis due to prolonged ischemia.

• Symptoms: Severe angina, lasting more than 30 minutes, with little relief at rest and with nitroglycerin.

Diagnosis:

• Clinical: based on history, symptoms, and physical examination.

• Electrocardiogram (ECG): characteristic ST-T changes.

• Blood tests: elevated cardiac enzymes.

• Coronary angiography: assesses the degree of CA stenosis.

Treatment:

• Medical treatment:

• Aborting an attack: sublingual nitroglycerin.

• Beyond the attack:

• Long-acting nitrates

• Beta-blockers

• Calcium channel blockers

• Aspirin

• Percutaneous coronary intervention (PCI): stent placement in the narrowed CA.

• Coronary artery bypass surgery: grafting of saphenous vein or internal mammary artery to the damaged CA.

Prevention:

• Identifying risk factors: smoking, high blood pressure, high cholesterol, diabetes, obesity, physical inactivity.

• Lifestyle modification: quit smoking, control blood pressure, cholesterol, and blood sugar, regular exercise, healthy diet.

Note:

Coronary artery disease is a serious condition that requires timely diagnosis and treatment. Lifestyle changes and adherence to treatment are essential to minimize complications and improve quality of life.