What is chronic angina
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Chronic Angina (Chronic Stable Angina / Chronic Ischemic Heart Disease)
Definition
Angina pectoris is chest discomfort or adjacent-area discomfort that occurs predictably and reproducibly at a certain level of exertion and is relieved by rest or nitroglycerin. It results from an imbalance between myocardial oxygen supply and demand.
Chronic angina specifically refers to a long-standing, stable pattern of ischemic symptoms, as opposed to an acute coronary syndrome (ACS). It may result from:
- Epicardial coronary artery obstruction (most common — atherosclerotic plaque)
- Vasospasm of epicardial coronary arteries or the microcirculation
- Microvascular angina (especially in women) — involvement of arteriolar resistance vessels with impaired coronary vasodilator reserve
- Noncoronary/nonvascular processes: myocardial energy derangements, blood rheology abnormalities, or extravascular microcirculatory compression
More than 15 million Americans have ischemic heart disease, and 50% of them have chronic angina. — Washington Manual of Medical Therapeutics
Pathophysiology
Two main mechanisms drive myocardial ischemia in the chronic setting:
| Mechanism | Description |
|---|---|
| Demand angina | Increased myocardial O₂ requirements (exercise, emotion, stress, fever, thyrotoxicosis, severe anemia) exceed what stenotic vessels can supply |
| Supply angina | Diminished O₂ delivery — vasospasm, microvascular disease, severe anemia, hypoxemia, CO poisoning, hyperviscosity |
The common final pathway: stenotic coronary arteries cannot augment antegrade flow in response to increased demand, causing ischemia and discomfort.
Symptoms
- Chest discomfort — pressure, squeezing, heaviness, or tightness; typically substernal; may radiate to the left arm, jaw, neck, or back
- Occurs predictably with exertion or emotional stress; relieved within minutes by rest or sublingual nitroglycerin
- Episodes typically last 2–10 minutes; >15–20 minutes at rest suggests ACS/MI
- Anginal equivalents: dyspnea, fatigue, diminishing exercise tolerance (especially in elderly and diabetics)
- Silent myocardial ischemia: objective ischemia (ECG or imaging) without symptoms — occurs in a subset of patients
Features that suggest noncardiac pain: pleuritic, reproduced by chest-wall palpation, sharp and constant for hours, localizable to one finger, or lasting only seconds.
Diagnosis
Initial Workup
- 12-lead ECG at rest — may be normal; transient ST changes during pain are diagnostic
- Blood tests: lipid panel, fasting glucose/HbA1c, CBC (anemia), thyroid function, hs-CRP
- Chest X-ray: assess cardiac size and pulmonary vasculature
Noninvasive Stress Testing
| Test | Sensitivity | Specificity |
|---|---|---|
| Stress ECG alone | 58% | 62% |
| Stress echocardiography | 85% | 82% |
| CCTA (coronary CT angiography) | 97% | 78% |
| SPECT nuclear imaging | 87% | 70% |
| PET | 90% | 85% |
| Stress cardiac MRI | 90% | 80% |
- Pharmacologic stress (dipyridamole, adenosine, regadenoson, dobutamine) is used when patients cannot exercise adequately (~40–50% of patients)
- β-blockers reduce the sensitivity of exercise testing and should ideally be held 2–3 days before
Invasive Testing
- Coronary angiography is indicated for risk stratification, prior to revascularization, or when noninvasive tests are inconclusive
Risk Stratification
High-risk features include:
- LV dysfunction (EF < 50%)
- Extensive/severe coronary artery disease (left main, triple-vessel, proximal LAD disease)
- Strongly abnormal exercise test
- Diabetes mellitus, prior MI, older age, male sex
- Severe or worsening angina with dyspnea
Treatment
General Measures
- Smoking cessation
- Dietary modification, weight reduction
- Treat hypertension, hyperlipidemia (LDL target < 55 mg/dL), and diabetes
- Supervised exercise prescription / cardiac rehabilitation
Pharmacologic Therapy
To prevent MI and death:
- Aspirin (absent contraindications)
- β-blockers — first-line; especially if prior MI
- ACE inhibitor — if diabetes, LV dysfunction, or vascular disease
- High-intensity statins ± ezetimibe ± PCSK9 inhibitors (LDL < 55 mg/dL)
- Rivaroxaban 2.5 mg BID + aspirin 81 mg (select high-risk patients)
To relieve symptoms:
- Sublingual nitroglycerin (or spray) — acute relief
- Long-acting nitrates — prophylaxis and symptom reduction
- Calcium channel blockers — first-line alternative to β-blockers; also combined with β-blockers if needed
- Ranolazine — FDA-approved for chronic angina; reduces late inward Na⁺ current; also reduces AF and ventricular arrhythmias
Revascularization
- Percutaneous coronary intervention (PCI) or CABG based on anatomy (SYNTAX score), LV function, and symptom burden
- CABG survival benefit demonstrated in: left main > 50%, triple-vessel disease, double-vessel disease with proximal LAD involvement, abnormal LV function, or strongly positive stress test
Sources: Goldman-Cecil Medicine, 26th Ed.; Washington Manual of Medical Therapeutics; Braunwald's Heart Disease, 12th Ed.
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