creation date: 2025-10-20 16:22
tags: Pathologies
Coronary Artery Disease
Background
Definitions
Coronary artery disease (CAD) is characterized by atherosclerosis in the coronary arteries.
Coronary heart disease (CHD) also referred to as ischemic heart disease includes conditions such as stable angina, acute coronary syndrome, and silent myocardial ischemia. As CHD primarily stems from CAD, they are often thought of synonymously.
Etiology
CAD is multifactorial which include both nonmodifiable and modifiable categories.
Nonmodifiable
- Male sex
- Age
- Family history and genetics
Modifiable - Hypertension
- Smoking
- Obesity (specifically waist circumference)
- Hypercholesterolemia (increased LDL)
- Psychosocial variables
Pathogenesis
The atherosclerosis characterizing CAD results in the formation of plaques in the lumen of the coronary arteries. This occurs when a vascular insult occurs in which the intima layer breaks. Monocytes migrate to the subendothelial space and become macrophages.
The macrophages take up oxidized LDL particles forming “foam cells” which deposits on the subendothelium. Further inflammatory activation results in smooth muscle uptake of oxidized LDL and collagen and deposition along side the foam cells. This results in a “fatty streak” or subendothelial plaque.
The plaque can grow or stabilize depending if further insults occur. As the plaque stabilizes, a fibrous cap forms and the lesion calcifies.
The lesion can thus impedes blood flow and causes an inadequate supply of blood and oxygen to the myocardium. If an obstruction blocks ≥70% of the lumen, this can results in symptoms during increased demand (angina). At ≥90% stenosis, symptoms may be present at rest. In acute obstruction, ACS can manifest.
Clinical Presentation
Signs & Symptoms
CAD can be present asymptomatically especially at low levels of coronary artery occlusion.
The primary symptom of CAD is pain referred to as angina pectoris:
- Gradual onset
- Discomfort in the chest (particularly behind the sternum)
- Triggered by or worsened by exertion
- Radiates to left arm, neck, jaw, teeth, ear
Angina pectoris is classified as stable (only with exertion) or unstable (sudden, even at rest).
Other symptoms include shortness of breath, nausea, and dizziness.
Atypical presentation includes:
- Epigastric or back pain
- Description of burning, stabbing, or indigestion
- Easy fatigability
In more severe cases, findings associated with acute coronary syndrome will be seen and are discussed separately.
History & Physical Exam
History should elicit relevant risk factors as well as any manifestations of symptoms. It is important to consider atypical manifestations especially in women due to the high risk of mortality.
Physical examination should include a thorough cardiovascular exam including acute distress, JVD, and peripheral edema. Additionally, auscultation of the lungs should occur, especially the lower lobes.
Diagnosis
Criteria
The American College of Cardiology and American Heart Association recommend the diagnostic criteria require some or all of the following:
- Clinical evidence such as past history of MI or angina symptoms
- Anatomic evidence as detected by coronary angiography (invasive or CT)
- Functional evidence as demonstrated by myocardial ischemia through noninvasive stress testing or invasive physiological assessment
With angiography, CAD can be classified as either obstructive, defined by stenosis ≥70% in a major epicardial artery or ≥50% in the LMCA, or nonobstructive, defined by stenosis between 1-69% in a major epicardial artery or 1-49% in the LMCA.
Work-up
Several modalities can be used for evaluation of CAD.
Electrocardiogram
- Rules out acute processes
- Clues on abnormalities, conditions, arrythmias
Echocardiography
- Rules out acute pulmonary pathologies and pericardial evaluation
- Detects wall motion, valvular regurgitation and stenosis, lesions, chamber sizes
Stress testing
- Noninvasive testing can expose anginal symptoms in exertional context
Chest radiography
- Cost-effective examination of the heart, lungs, and vasculature
Serum markers
- Cardiac enzymes and BNP (more acute)
- CBC
- Metabolic panels
- Lipid panels
Cardiac catheterization
- Gold standard for evaluation of ischemic coronary artery disease via angiography
- Not routine due to invasive nature; typically for high suspicion for CAD or in ACS situations
Coronary Calcium Score and CT angiography
- CT is used to determine the amount of calcium is within the coronary arteries
- CAC score and risk is described as follows:
- 0: no calcified plaque and thus low risk (not zero however)
- 1-10: low overall risk but evidence of early atherosclerosis
- 11-100: moderate plaque burden with risk of heart attack
- 101-400: moderate to high risk
-
400: high risk with significant coronary artery blockage
- High sensitivity; score of 0 can effectively rule out obstructive or high risk CAD
Differential
Acute anginal chest pain can be due to a number of different conditions. This is discussed separately as t he chest pain workup.
Red Flags / Complications
Life threatening red-flags include those of ACS. It is important to rule out STEMIs and NSTEMIs with CAD. Additionally, unrecognized CAD can lead to long-term mortality and careful consideration of atypical presentations is warranted.
Management
The management of acute coronary syndrome is discussed separately. This section primarily discusses chronic coronary syndrome, also referred to as stable ischemic heart disease.
Non-pharmacological
In the mildest forms of CAD, non-pharmacological intervention alone may be sufficient to slow the progression of disease. In more severe CAD, non-pharmacological management should be used in conjunction with therapies.
Non-pharmacological management include:
- Lifestyle modifications including diet changes to reduce fat and cholesterol
- Exercise
- Smoking cessation
- Weight management
Management of other risk factors such as hypertension and diabetes are also important.
Pharmacological
For stable disease, guidelines suggest the initiation of:
- Low-dose aspirin
- Beta-blocker
- Moderate-to-high-intensity statin
- Nitroglycerin prn anginal pain
If symptoms are not controlled even with guideline-directed medical therapy:
- Beta blocker can be titrated up to goal HR of 55-60
- Addition of calcium channel blocker
- Addition of long-acting nitrates
If symptoms are still refractor, PCI or CABG may be considered.