Coronary Artery Disease and Stable Angina

Descriptive text is not available for this image BASICS

Cardiovascular diseases are a major cause of death worldwide. Coronary artery disease (CAD) is a highly prevalent cardiovascular condition and a significant health burden for the population.

DESCRIPTION

  • CAD refers to the atherosclerotic narrowing of the epicardial coronary arteries. It may manifest insidiously as angina pectoris or as an acute coronary syndrome (ACS).
  • Stable angina is a chest discomfort due to myocardial ischemia that is reproducible at a certain level of exertion or emotional stress.
  • The spectrum of ACS includes unstable angina (UA), non–ST elevation myocardial infarction (NSTEMI), and ST elevation myocardial infarction (STEMI). See “Acute Coronary Syndromes: NSTE-ACS (Unstable Angina and NSTEMI).”
  • Definitions
    • Typical angina: three classical characteristics: (i) substernal chest pressure, pressure or heaviness that may radiate to the jaw, back, or arms and generally lasts from 2 to 15 minutes; (ii) occurs at a certain level of myocardial oxygen demand from exertion, emotional stress, or increased sympathetic tone; and (iii) relieved with rest or sublingual nitroglycerin
    • Atypical angina: exhibits two of the above typical characteristics
    • Noncardiac chest pain: exhibits ≤1 of the above typical characteristics
    • Anginal equivalent: Patients may present without chest discomfort but with nonspecific symptoms such as dyspnea, diaphoresis, fatigue, belching, nausea, light-headedness, or indigestion that occur with exertion or stress.
    • UA: anginal symptoms that are new or more frequent, more severe, or occurring with lessening degrees of myocardial demand; considered ACS but do not present with cardiac biomarker elevation.
    • NSTEMI: elevation of cardiac biomarker (troponin) with either anginal symptoms, ischemic ECG changes other than ST elevation, or both.
    • STEMI: presents with typical symptoms as mentioned above with ST elevations noted on ECG; generally caused by acute plaque rupture and complete obstruction of culprit vessel and may present prior to laboratory detection of troponin.

Geriatric Considerations
The elderly may present with atypical symptoms. Physical limitations may delay recognition of angina until it occurs with minimal exertion or at rest. Maintain a high degree of suspicion during evaluation of dyspnea and other nonspecific complaints.

EPIDEMIOLOGY

  • CAD causes about 1 in 5 deaths in the United States. Heart disease cost about $252.2 billion in 2019 to 2020 (Centers for Disease Control and Prevention) and $378 billion (American Heart Association [AHA]) annually for 2017 to 2019.
  • ~80% of CAD is preventable with a healthy lifestyle.

Incidence

In the United States, the lifetime incidence risk of developing CAD in men and women after 40 years of age is 49% and 32%, respectively.

Prevalence

Approximately 20.1 million persons in the United States live with CAD; 11.1 million Americans have chronic stable angina pectoris and 8.8 million persons with CAD had myocardial infarction.

ETIOLOGY AND PATHOPHYSIOLOGY

Anginal symptoms occur during times of myocardial ischemia caused by a mismatch between coronary perfusion and myocardial oxygen demand. Atherosclerotic narrowing of the coronary arteries is the most common etiology of angina, but it may also occur in those with significant aortic stenosis, pulmonary hypertension, hypertrophic cardiomyopathy, coronary spasm, or volume overload.

Genetics

Many CAD-associated single-nucleotide polymorphisms have been identified, although many of their functions are not well characterized. TGF-beta 1 associated to TGF beta gene and its receptor is an important mediator of inflammation that may be involved in the inflammatory process that occurs in the coronary vessels.

RISK FACTORS

  • Classical risk factors: hypertension, ↑ LDL cholesterol, smoking, diabetes, premature CAD in first-degree relatives (men <55 years old; women <65 years old), age (>45 years for men; >55 years for women), ↓ HDL
  • Other risk factors: obesity, sedentary lifestyle, chronic inflammation, abnormal ankle-brachial indices, renal disease

GENERAL PREVENTION

  • Smoking cessation
  • Regular aerobic exercise program and weight loss for obese patients (goal body mass index [BMI] <25 kg/m2); a plant-based or Mediterranean-like diet is recommended.
  • Blood pressure (BP) control (goal <140/90 mm Hg; consider <130/80 mm Hg for those with 10-year ASCVD risk ≥10%.)
  • Type 2 diabetes management: Consider more aggressive hemoglobin A1c (HbA1c) goal of 6.5–7% in younger, recently diagnosed individuals.
  • At least moderate-intensity statin therapy for those with diabetes aged 40 to 75 years and those with 10-year ASCVD risk ≥7.5–20% (Recommendations of advisory organizations vary. Caution: the older American College of Cardiology [ACC]/AHA risk calculator overestimates risk in many by as much as 50–100%. Newer calculators are available online and may be more accurate)

COMMONLY ASSOCIATED CONDITIONS

Hyperlipidemia, peripheral vascular disease, cerebrovascular disease, hypertension, obesity, diabetes

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