Chronic coronary syndrome (stable coronary artery disease)

Definition

Coronary artery disease (CAD) is the manifestation of atherosclerosis in the coronary arteries. Chronic coronary syndrome (CCS) refers to its stable phases: flow-limiting stenoses or dysfunction of the small vessels cause a mismatch between myocardial oxygen supply and demand during exertion (myocardial ischemia). The cardinal symptom is stable angina.

Classification

• Typical angina: retrosternal pressure or tightness, provoked by exertion or emotional stress and subsiding within a few minutes at rest. Atypical symptoms (epigastric or back discomfort, palpitations) occur particularly in women.
• CCS classification (Canadian Cardiovascular Society): grade I angina only with strenuous or prolonged exertion; II slight limitation of ordinary activity; III marked limitation when walking on level ground or climbing one flight of stairs; IV symptoms with any activity or at rest.
• Special forms: vasospastic (Prinzmetal) angina with pain at rest and transient ST elevation; microvascular angina. Both can cause ischemia with non-obstructive coronary arteries.
• By extent: single-, two- or three-vessel disease, left main stenosis.

Occurrence & epidemiology

CAD is among the most common chronic diseases and the leading cause of death in both sexes (about 15 % of all deaths worldwide). The frequency rises markedly with age.

Aetiopathogenesis

The process begins with endothelial dysfunction. LDL particles accumulate in the intima, become oxidized and are taken up by macrophages (foam cells); fatty streaks develop into fibrous plaques with a lipid core and later calcification. Without pressure-wire measurement, a stenosis is considered hemodynamically significant when the luminal diameter is reduced by more than 70 %.

Ischemia follows a typical cascade: perfusion abnormality, diastolic then systolic dysfunction (wall motion abnormality), ECG changes and only finally angina.

Risk factors: smoking, hypertension, dyslipidemia (LDL cholesterol, apolipoprotein B), diabetes mellitus, age, male sex, family history, obesity, physical inactivity, chronic kidney disease and chronic inflammation.

Clinical features

Typical are exertional retrosternal pressure or tightness, possibly radiating to the arms, neck, jaw or epigastrium, which resolves at rest after a few minutes. Cold, heavy meals and emotional stress are also triggers. Exertional dyspnea can be the only symptom (angina equivalent); silent ischemia is particularly common in diabetes mellitus.

Possible consequences are acute coronary syndrome, ischemic cardiomyopathy with heart failure, arrhythmias and sudden cardiac death.

Diagnosis

Diagnostic work-up

• History and examination: character of symptoms, risk factors; signs of heart failure, valvular heart disease or peripheral artery disease
• Laboratory tests: blood count (anemia), lipid profile, glucose and HbA1c, creatinine and eGFR, TSH
• Resting ECG (often normal; Q waves after infarction, repolarization abnormalities) and echocardiography (pump function, regional wall motion abnormalities, valve disease)
• The clinical likelihood based on age, sex, symptoms and risk factors determines which test is most informative.
• Coronary CT angiography: excludes coronary stenosis in stable angina with high accuracy (sensitivity 93–99 %); noninvasive FFR estimation (CT-FFR) is also possible
• Functional ischemia testing: stress echocardiography (exercise or pharmacological), myocardial perfusion SPECT or PET, stress perfusion MRI; exercise ECG has lower sensitivity
• Invasive coronary angiography with pressure-wire measurement (FFR) to assess the functional significance of intermediate stenoses; if vasospastic or microvascular angina is suspected, provocation and coronary function testing

Keep learning in the app

Further reading (open access)

1. MSD Manual Professional: Stable Angina
2. MSD Manual Professional: Overview of Coronary Artery Disease
3. Nationale VersorgungsLeitlinie: Chronische KHK
4. StatPearls: Stable Angina
5. StatPearls: Coronary Artery Disease
6. MSD Manual Professional: Vasospastic Angina

Cross-references