Is chronic coronary syndrome a recognized clinical entity for a patient with typical exertional chest discomfort and dyspnea that is predictable, reproducible, and relieved by rest or nitroglycerin without evidence of acute plaque rupture?

Chronic Coronary Syndrome is a Recognized Clinical Entity

Yes, chronic coronary syndrome (CCS) is an established clinical entity that replaced the outdated term "stable coronary artery disease" to better reflect the dynamic, progressive nature of coronary disease during non-acute phases. 1

Definition and Pathophysiology

The European Society of Cardiology formally introduced the term "chronic coronary syndromes" in 2019 and updated it in 2024 to describe clinical presentations of coronary artery disease during stable periods, particularly those preceding or following acute coronary syndrome. 1

CCS is defined as: "a range of clinical presentations or syndromes that arise due to structural and/or functional alterations related to chronic diseases of the coronary arteries and/or microcirculation. These alterations can lead to transient, reversible, myocardial demand vs. blood supply mismatch resulting in hypoperfusion (ischemia), usually (but not always) provoked by exertion, emotion or other stress, and may manifest as angina, other chest discomfort, or dyspnea, or be asymptomatic." 1

The terminology shift from "stable" to "chronic" is deliberate—coronary disease is never truly stable, as it remains progressive and can destabilize at any moment with development of acute coronary syndrome. 1, 2, 3, 4

Your Patient's Presentation Fits CCS Criteria

The patient you describe—with typical exertional chest discomfort and dyspnea that is predictable, reproducible, and relieved by rest or nitroglycerin without acute plaque rupture—represents a classic CCS presentation. 1

Typical angina characteristics (all three must be present):

• Substernal chest discomfort of characteristic quality and duration 1
• Provoked by exertion or emotional stress 1
• Relieved by rest and/or nitroglycerin within minutes 1

Your patient meets all three criteria, confirming typical angina as part of the CCS spectrum. 1

Expanded Pathophysiological Understanding

Modern concepts recognize that CCS encompasses far more than fixed epicardial stenoses. 1

Macrovascular contributors:

• Fixed, flow-limiting stenoses 1
• Diffuse atherosclerotic lesions without identifiable luminal narrowing 1
• Myocardial bridging and congenital arterial anomalies 1
• Dynamic epicardial vasospasm 1

Microvascular contributors:

• Coronary microvascular dysfunction (CMD) is increasingly recognized as prevalent across the entire CCS spectrum 1
• Functional and structural microcirculatory abnormalities can cause angina and ischemia even with non-obstructive epicardial disease (ANOCA/INOCA) 1

Systemic contributors:

• Anemia, tachycardia, blood pressure changes, myocardial hypertrophy, and fibrosis may contribute to non-acute myocardial ischemia 1

Clinical Spectrum of CCS

The 2024 ESC Guidelines identify six clinical scenarios within CCS: 1

1. Stress-induced angina or equivalent with obstructive CAD 1
2. Angina or equivalent with non-obstructive CAD (ANOCA/INOCA) 1
3. Stabilized phase after acute coronary syndrome, PCI, or CABG 1
4. Asymptomatic individuals with abnormal coronary anatomical or functional tests 1
5. Left ventricular dysfunction or heart failure of ischemic origin 1

Your patient fits scenario #1 or potentially #2 depending on coronary anatomy. 1

Critical Distinction from Acute Coronary Syndrome

CCS is fundamentally different from unstable angina/NSTE-ACS, which requires immediate hospitalization. 5

Red flags that indicate acute coronary syndrome (NOT CCS):

• Rest angina lasting >10 minutes 1, 5
• New-onset severe angina (Canadian Cardiovascular Society Class III-IV) 1
• Accelerating pattern—increasing frequency, severity, or duration 1
• ST segment depression on ECG during symptoms 5

Your patient's predictable, reproducible, exertional pattern that resolves with rest confirms CCS rather than acute coronary syndrome. 1

Prognostic Implications

Despite the "chronic" designation, CCS carries significant morbidity and mortality risk. The CLARIFY registry of 32,703 patients showed a 5-year cardiovascular death or MI rate of 8.0%. 6

Highest-risk CCS subgroup identified:

• Patients with both angina AND prior MI had an 11.8% 5-year event rate 6
• Patients with angina but no prior MI had only 6.3% 5-year event rate 6
• This interaction (p=0.0016) identifies an easily recognizable high-risk population requiring intensive treatment 6

Management Approach

The 2024 ESC Guidelines recommend a four-step algorithm: 1

Step 1: General clinical evaluation with 12-lead ECG and basic blood tests to rule out acute coronary syndrome and non-cardiac causes 1

Step 2: Echocardiography at rest to assess LV function and estimate pre-test likelihood of obstructive CAD using the Risk Factor-weighted Clinical Likelihood model 1

Step 3: Diagnostic testing based on pre-test probability:

• Low-moderate likelihood (>5%-50%): Coronary CT angiography recommended 1
• Moderate-high likelihood (>15%-85%): Stress echocardiography or other functional imaging recommended 1

Step 4: Guideline-directed medical therapy for all patients, with revascularization reserved for refractory symptoms or high-risk anatomy 1

Common Pitfall to Avoid

Do not use nitroglycerin response as a diagnostic test. The European Society of Cardiology explicitly warns that nitroglycerin response "can be misleading" and should not distinguish cardiac from non-cardiac pain or differentiate stable from unstable presentations. 5 Relief with nitroglycerin supports but does not confirm ischemic etiology, as many non-cardiac conditions respond to nitrates. 5