Stable Angina

Stable angina is a clinical syndrome characterized by recurrent episodes of chest pain or discomfort, typically triggered by physical exertion or emotional stress and relieved by rest or nitrate administration. It is caused by a transient myocardial ischemia, resulting from an imbalance between myocardial oxygen demand and supply, primarily due to fixed atherosclerotic stenosis of the coronary arteries.
The underlying mechanism of this condition is a progressive reduction in the caliber of the coronary arteries due to the formation of atherosclerotic plaques, which limit blood flow under increased myocardial demand. Additionally, endothelial dysfunction and increased vascular tone can contribute to reduced myocardial perfusion, worsening the ischemic condition.

Epidemiology and Risk Factors

Stable angina is one of the most common manifestations of chronic ischemic heart disease.
Its prevalence increases with age and with the presence of cardiovascular risk factors such as hypertension, dyslipidemia, diabetes mellitus, smoking, and a sedentary lifestyle.
Hypertension promotes the progression of atherosclerosis and increases ventricular afterload, while dyslipidemia accelerates the formation of atherosclerotic plaques through LDL accumulation and reduced HDL levels.
Diabetes mellitus contributes to endothelial dysfunction and microvascular abnormalities, while smoking amplifies thrombotic risk and promotes chronic inflammation.
Obesity and physical inactivity are also significant risk factors, as they contribute to metabolic syndrome and insulin resistance.

Classification of Angina According to the Canadian Cardiovascular Society (CCS)

• Class I: Angina occurs only with intense and prolonged exertion.
• Class II: Angina with moderate activity, such as walking uphill or over long distances.
• Class III: Angina with light activities, such as walking short distances on level ground.
• Class IV: Angina at rest or with minimal exertion.

Diagnosis and Diagnostic Tests

The diagnosis is based on history, physical examination, and instrumental tests to confirm the presence of myocardial ischemia.

History is essential to characterize chest pain. In stable angina, the patient reports oppressive or constrictive retrosternal pain, possibly radiating to the left arm, neck, or jaw. Pain predictably occurs with exertion or emotional stress and resolves within a few minutes with rest or nitrate administration.

The physical examination is usually normal, but in some cases, a fourth heart sound (S4) may be detected, indicating altered left ventricular compliance.

For diagnostic confirmation, instrumental tests are used.
The baseline ECG may be normal or show T-wave abnormalities and ST-segment depression. The exercise stress test is positive in the presence of ST-segment depression ≥1 mm.
The 24-hour Holter ECG may be useful in patients with atypical symptoms, identifying episodes of silent ischemia or ischemic arrhythmias.
The stress echocardiography assesses myocardial contractility under physical or pharmacological stress, detecting areas of hypokinesia, akinesia, or dyskinesia suggestive of inducible ischemia. Myocardial scintigraphy distinguishes reversible perfusion deficits (ischemia) from fixed deficits (previous infarction), while coronary angiography is the gold standard for assessing coronary artery disease.
Cardiac MRI with stress uses vasodilator drugs (adenosine, regadenoson, dipyridamole) or inotropic agents (dobutamine) to simulate physiological stress, allowing the identification of myocardial perfusion deficits, assessment of ventricular function, and detection of fibrotic areas using the Late Gadolinium Enhancement (LGE) technique.

Treatment of Stable Angina

Treatment aims to reduce symptoms and prevent cardiovascular events.

Lifestyle modifications play a crucial role in disease management. Smoking cessation significantly reduces the risk of ischemic events, while regular physical activity improves cardiovascular capacity and metabolic control. A balanced diet, based on the Mediterranean model, helps reduce cholesterol levels and maintain a healthy body weight.

Pharmacological therapy includes beta-blockers and calcium channel blockers to reduce myocardial oxygen consumption, antiplatelet agents for preventing thrombotic events, statins for atherosclerosis control, and ACE inhibitors or sartans in patients with hypertension or ventricular dysfunction.

Myocardial revascularization can be performed through percutaneous coronary angioplasty (PCI) in patients with critical stenosis or through coronary artery bypass grafting (CABG) in cases of multivessel disease.

Prognosis and Complications

When properly treated, stable angina has a favorable prognosis. However, if inadequately managed, it may progress to acute coronary syndrome, ventricular arrhythmias, or ischemic heart failure.

References
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