What is stable ischemic heart disease?

Stable Ischemic Heart Disease (SIHD)

Stable ischemic heart disease is a condition characterized by episodes of reversible myocardial oxygen demand/supply mismatch, typically resulting in predictable angina symptoms during exertion or stress that resolve with rest or nitroglycerin, caused by coronary artery disease or functional alterations in coronary circulation. 1

Definition and Pathophysiology

Stable ischemic heart disease (SIHD) represents a spectrum of clinical conditions where there is inadequate oxygen supply to the myocardium relative to demand. The key pathophysiological mechanisms include:

• Plaque-related obstruction of epicardial arteries - Fixed atherosclerotic narrowings (≥50% in left main or ≥70% in other major coronary arteries) 1
• Microvascular dysfunction - Abnormalities in the coronary microcirculation 1
• Coronary vasospasm - Focal or diffuse spasm of normal or plaque-diseased arteries 1
• Left ventricular dysfunction - From prior myocardial necrosis or hibernation (ischemic cardiomyopathy) 1

These mechanisms may occur alone or in combination, and can change over time in the same patient 1.

Clinical Presentation

Typical Angina Symptoms

• Quality: Often described as "squeezing," "griplike," "suffocating," or "heavy" 1
• Location: Typically retrosternal
• Duration: Usually brief (minutes)
• Radiation: May radiate to jaw, neck, arms (especially left)
• Alleviating factors: Rest, nitroglycerin
• Precipitating factors: Physical exertion, emotional stress, cold weather 1

Atypical Presentations

• Sharp chest pain (not typical angina)
• Nausea, vomiting, midepigastric discomfort
• More common in women and elderly patients 1, 2

Clinical Classifications

1. Effort-induced angina - Due to epicardial stenoses, microvascular dysfunction, or vasoconstriction 1
2. Rest angina - Due to vasospasm (focal or diffuse) 1
3. Asymptomatic - Despite presence of ischemia and/or left ventricular dysfunction 1

Epidemiology

SIHD is a major public health problem with:

• Prevalence increases with age in both sexes 1
• 5-7% in women aged 45-64 years, increasing to 10-12% in women aged 65-84 1
• 4-7% in men aged 45-64 years, increasing to 12-14% in men aged 65-84 1
• More prevalent in middle-aged women than men (due to higher prevalence of microvascular angina) 1
• More prevalent in elderly men than women 1

Risk Factors

Key risk factors for developing SIHD include:

• Smoking
• Hyperlipidemia
• Diabetes mellitus
• Hypertension
• Family history of premature coronary artery disease
• Obesity or metabolic syndrome
• Physical inactivity
• History of cerebrovascular or peripheral vascular disease 1, 2

Diagnostic Approach

Initial Evaluation

1. Thorough history and physical examination to assess probability of IHD 1, 2
2. Resting ECG for all patients without an obvious non-cardiac cause of chest pain 1
3. Risk stratification - Categorize patients with acute angina as stable or unstable; those with unstable angina should be further classified by risk level 1

Noninvasive Testing

Based on pretest probability and patient characteristics:

• Standard exercise ECG - First choice for patients with intermediate pretest probability, interpretable ECG, and adequate physical functioning 1
• Exercise stress with imaging (radionuclide myocardial perfusion imaging or echocardiography) - For patients with uninterpretable ECG 1
• Pharmacologic stress testing - For patients unable to exercise adequately 1

Coronary Angiography

Indicated in specific scenarios:

• Survivors of sudden cardiac death or life-threatening ventricular arrhythmia 1
• Development of heart failure symptoms 1
• High likelihood of severe IHD based on clinical characteristics and noninvasive testing 1

Important Clinical Considerations

• Distinguishing stable from unstable angina is critical - patients with unstable angina at high or moderate risk require prompt transfer to an emergency department or coronary care unit 1
• Shared decision-making between provider and patient is essential when choosing diagnostic and therapeutic options 1
• Alternative diagnoses should be considered in patients with atypical symptoms (pulmonary, gastrointestinal, musculoskeletal causes) 1
• Avoid unnecessary testing - pharmacologic stress imaging or CT angiography should not be used in patients who can exercise adequately with interpretable ECG 1
• Coronary angiography should not be used for risk assessment in patients who are not candidates for revascularization or have low-risk findings on noninvasive testing 1

By understanding the pathophysiology, clinical presentation, and appropriate diagnostic approach to SIHD, clinicians can effectively evaluate patients with chest pain and implement appropriate management strategies to reduce morbidity and mortality.