Structural Heart Disease vs. Coronary Artery Disease: Distinct Cardiovascular Conditions
No, structural heart disease and coronary artery disease are not the same conditions; they represent different pathophysiological processes affecting the cardiovascular system, although they can coexist in the same patient. 1, 2
Definitions and Key Differences
Coronary Artery Disease (CAD)
- Defined as a pathological process characterized by atherosclerotic plaque accumulation in the epicardial arteries, whether obstructive or non-obstructive 1
- Primarily affects the blood supply to the heart muscle through the coronary circulation
- Manifests clinically as Chronic Coronary Syndromes (CCS) or Acute Coronary Syndromes (ACS)
- Pathophysiology centers on atherosclerosis, inflammation, thrombosis, and endothelial dysfunction 3
Structural Heart Disease
- Encompasses abnormalities in cardiac structure or function, excluding primary valvular diseases 2
- Includes conditions affecting the myocardium, cardiac chambers, septum, and other structural components
- Can be classified into progressive stages from risk factors (Stage A) to refractory heart failure (Stage D) 2
- Examples include cardiomyopathies, congenital heart defects, and myocardial remodeling after injury
Pathophysiological Mechanisms
Coronary Artery Disease Mechanisms
- Epicardial coronary obstruction (traditional focus)
- Microvascular dysfunction
- Epicardial vasospasm
- Diffuse non-obstructive atherosclerosis 1
- Myocardial bridges causing dynamic compression 1
Structural Heart Disease Mechanisms
- Myocardial injury leading to remodeling
- Ventricular hypertrophy
- Chamber dilation
- Fibrosis and scarring
- Altered cardiac architecture and mechanical performance 2
Clinical Manifestations and Diagnosis
Coronary Artery Disease
- Presents as angina pectoris, myocardial infarction, or ischemic heart failure
- Diagnosis relies on:
- Stress testing
- Coronary angiography
- Coronary CT angiography
- Functional testing for ischemia 1
Structural Heart Disease
- Presents as heart failure, arrhythmias, or may be asymptomatic
- Diagnosis relies on:
- Echocardiography (primary diagnostic tool)
- Cardiac MRI
- CT imaging
- Nuclear studies 2
Evolving Concepts in Classification
The European Society of Cardiology has moved toward using the term "Chronic Coronary Syndromes" (CCS) rather than "stable CAD," recognizing that coronary artery disease exists on a spectrum with acute presentations 1. Similarly, American guidelines have shifted from "Stable Ischemic Heart Disease" (SIHD) to "Chronic Coronary Disease" (CCD) 1.
Recent guidelines acknowledge that myocardial ischemia can occur through multiple mechanisms beyond just obstructive coronary disease, including:
- Ischemia with non-obstructive coronary arteries (INOCA)
- Angina with non-obstructive coronary arteries (ANOCA) 1
Relationship and Coexistence
While distinct, these conditions frequently coexist:
- Coronary artery disease can lead to myocardial injury and subsequent structural remodeling
- Structural heart disease can increase myocardial oxygen demand, worsening the impact of coronary artery disease
- Both conditions share common risk factors (hypertension, diabetes, age) 1, 2
Treatment Approaches
Coronary Artery Disease Treatment
- Antiplatelet therapy
- Statins and lipid management
- Antihypertensive medications
- Revascularization (PCI or CABG) when appropriate 1
Structural Heart Disease Treatment
- ACE inhibitors or ARBs for ventricular remodeling
- Beta-blockers for rate control and reduction of adrenergic stimulation
- Device therapy (ICD, CRT) in appropriate patients
- Surgical correction of structural abnormalities 2
Clinical Implications
Understanding the distinction between these conditions is crucial for proper diagnosis and management. Patients with chest pain may have:
- Pure coronary artery disease
- Pure structural heart disease
- Both conditions simultaneously
- Neither condition (non-cardiac chest pain)
The 2024 ESC guidelines emphasize the importance of considering both coronary and non-coronary mechanisms when evaluating patients with suspected ischemic symptoms 1.
Recognizing that coronary artery disease and structural heart disease are distinct entities with different pathophysiological mechanisms allows for more targeted diagnostic approaches and treatment strategies, ultimately improving patient outcomes.