Chronic coronary syndrome

Chronic coronary syndrome (CCS) is a term that defines coronary artery disease as a chronic progressive course that can be altered, stabilized or improved by lifestyle modifications, pharmacotherapy and coronary revascularization. It has been introduced to replace the previous term ‘stable coronary artery disease’.

Chronic coronary syndrome constitutes one of the two forms of coronary artery disease with acute coronary syndrome being the other.

Epidemiology

Chronic coronary syndrome is the stable form of coronary artery disease and thus is very common ^1,2.

Associations

Chronic coronary syndrome is associated with coronary artery disease and often myocardial ischemia.

Clinical presentation

The following clinical scenarios are examples of frequently encountered chronic coronary syndromes ^1-4:

• suspected coronary artery disease with symptoms of ‘stable’ angina and/or dyspnea
• suspected coronary artery disease and new-onset heart failure or left ventricular dysfunction
• symptomatic or asymptomatic individuals with stabilized symptoms <1 year after an acute coronary syndrome or recent revascularization
• symptomatic or asymptomatic individuals >1 year after the initial diagnosis of coronary artery disease or coronary revascularization
• asymptomatic individuals in whom coronary artery disease was detected at screening
• symptoms of angina in suspected vasospastic coronary disease or microvascular disease

An exercise electrocardiogram can assess exercise tolerance and offers complementary information. ST-segment depression at low workload with associated symptoms as angina or dyspnea, arrhythmias and abnormal blood pressure indicates high risk ².

Complications

If left untreated chronic coronary syndromes can progress to an acute coronary syndrome with the following complications ¹:

• myocardial infarction
• heart failure
• sudden cardiac death

Pathology

The main pathological process of chronic coronary syndromes includes the one of coronary artery disease characterized by obstructive or non-obstructive atherosclerotic plaque formation in the epicardial arteries. Besides it also includes microvascular and/or vasospastic coronary disease without epicardial coronary disease.

Radiographic features

Imaging features of chronic coronary syndromes vary with the modality. While coronary CTA can demonstrate coronary artery disease and coronary stenosis in the epicardial arteries, noninvasive functional imaging as stress echocardiography, nuclear medicine stress test and stress cardiac MRI can demonstrate myocardial ischemia in the respective vascular territory.

Coronary CTA or noninvasive functional testing for myocardial ischemia are initial tests for the diagnosis of coronary artery disease in which coronary artery cannot be excluded clinically ¹.

Functional imaging is particularly useful in patients with a high clinical probability of coronary artery disease, long-standing chronic coronary syndrome, suspected microvascular disease or in cases where additional viability assessment is required ^1.2.

Plain radiograph

A chest x-ray is helpful in case of atypical symptoms, suspected heart failure or pulmonary disease but does not provide specific information for the diagnosis of a chronic coronary syndrome or risk stratification ¹.

Echocardiography

Echocardiography can identify related wall-motion abnormalities, assess systolic and diastolic function and detect potential alternative causes of the symptoms ^1,2.

Stress-echocardiography can demonstrate stress-induced wall motion abnormalities and thus indicates myocardial ischemia.

Stress-induced hypokinesia or akinesia in ≥3 of 16 segments is considered high risk ^3,4.

CT

Coronary CTA can detect coronary artery disease, can characterize coronary plaques positive and negative remodeling and coronary artery stenosis. It is particularly useful for the detection of coronary artery disease in patients with low to intermediate pretest probability It is less useful as a follow-up test in patients with established coronary artery disease ².

A reduction in coronary arterial luminal diameter of ≥50% might require further non-invasive functional testing ^1,2,5.

Significant stenosis (≥50%) of the left main coronary artery, high-grade (≥70% stenosis) of the proximal left anterior descending artery (LAD) or three-vessel obstructive disease indicates high risk and might require invasive coronary angiography (ICA) ^3,5,6.

CT based fractional flow reserve (CT-FFR) can aid in the determination of hemodynamic relevance of coronary stenosis ^2,5.

Coronary angiography

Invasive coronary angiography (ICA) will depict angiographic evidence of coronary stenosis.

Invasive functional testing is state of the art for evaluation of significant stenosis with a reduction in arterial luminal diameter of >50% or narrowing of >75% of the cross-sectional vessel area acquired by imaging modalities using a 3D data set.

A fractional flow reserve of ≤0.8 or an instantaneous wave-free ratio of ≤0.89 indicates a high-risk lesion ^1-3.

MRI

Cardiac MRI stress testing can show stress-induced perfusion defects assess wall-motion, cardiac function and myocardial viability ^1,2.

A stress-induced perfusion defect of >10% of the left ventricular myocardium or ≥2 of 16 segments following vasodilator tress is considered high risk.

Stress-induced wall motion abnormalities following inotropic stress ≥3 of 16 segments are considered high risk ³.

Nuclear medicine

Myocardial perfusion and viability testing can demonstrate myocardial ischemia. Stress or exercise-induced perfusion defect of ≥10% of the left ventricular myocardium indicates high-risk ^1-3.

PET features better accuracy than SPECT ².

Radiology report

The radiological report should include a description of the following features based on the AHA coronary artery segments or the cardiac segmentation model:

• cardiac CT
  • coronary artery disease as per CAD-RADS
• functional non-invasive testing
  • stress induced-wall motion abnormalities
  • stress-induced perfusion defect

Treatment and prognosis

Treatment of chronic coronary syndrome involves the following management steps ^1,3:

• lifestyle modification
  • smoking cessation
  • dietary modifications
  • physical training and weight reduction
• pharmacological therapy
  • anti-ischemic therapy with ß-blocker and/or calcium-channel blocker or nitrates
  • preventive antithrombotic therapy with low dose acetylsalicylic acid
  • lipid-lowering agents
  • angiotensin-converting enzyme (ACE) inhibitors in case of concomitant systemic arterial hypertension, reduced left-ventricular function (≤40%), diabetes mellitus or chronic renal failure
• percutaneous coronary intervention and revascularization in the following conditions:
  • symptoms despite optimal medical therapy and high cardiovascular risk
  • asymptomatic or mild symptoms but high cardiovascular risk after noninvasive testing
  • typical and profound symptoms in low-stress situations and high cardiovascular risk clinically
  • left ventricular dysfunction associated with typical angina and suspicion of coronary artery disease
  • unclear or conflicting results on non-invasive testing

History and etymology

The term chronic coronary syndrome was introduced by the European Society of Cardiology (ESC) at the European Congress of Cardiology in 2019 ¹.

Differential diagnosis

A chronic coronary syndrome can mimic the appearance or presentation of the following clinical conditions ¹:

• acute coronary syndrome
• myocarditis