What are the primary causes and management strategies for chest pain in patients with severe aortic stenosis?

Causes of Chest Pain in Severe Aortic Stenosis

Chest pain in severe aortic stenosis occurs primarily due to coronary microvascular dysfunction from elevated left ventricular pressure and hypertrophy, though coexisting obstructive coronary artery disease must also be excluded. 1

Primary Mechanisms

Coronary Microvascular Dysfunction (Most Common)

• Supply-demand mismatch is the predominant mechanism causing angina in severe AS, resulting from markedly elevated left ventricular pressure due to high afterload combined with left ventricular hypertrophy 1
• This occurs even in the absence of epicardial coronary disease and represents subendocardial ischemia from inadequate coronary perfusion relative to the hypertrophied myocardial mass 2
• The hypertrophied ventricle has increased oxygen demands that cannot be met by the coronary circulation, particularly during exertion 1

Obstructive Epicardial Coronary Artery Disease

• Coexisting CAD is common in AS patients due to shared risk factors and must be systematically evaluated 1
• The American College of Cardiology recommends preoperative coronary angiography in patients being evaluated for valve replacement, with decisions based on age, symptoms, and coronary risk factors 3
• Distinguishing between angina from AS versus CAD can be challenging, as severe AS itself interferes with hemodynamic assessment of intermediate coronary lesions 2

Clinical Presentation Patterns

Exercise-Induced Angina

• Exercise-induced chest pain is a cardinal symptom of severe AS and indicates abnormal exercise stress testing 1
• This represents a Class I indication for aortic valve replacement in symptomatic patients with severe AS 4

Angina Prevalence Across AS Severity

• Chest pain occurs commonly in both moderate (41.3%) and severe (47.7%) AS, though angina specifically shows similar prevalence between moderate and severe AS 5
• Important caveat: The presence of chest pain does not reliably distinguish AS severity, as comorbidities significantly contribute to symptom burden 5

Diagnostic Approach

Initial Evaluation

• Transthoracic echocardiography (TTE) is the first-line diagnostic tool (Class I recommendation) to determine AS severity, assess left ventricular function, and evaluate for other valvular pathology 1
• When TTE quality is inadequate, transesophageal echocardiography with 3D imaging is recommended 1

Coronary Assessment

• Coronary angiography is essential in the pre-intervention workup to identify concomitant CAD requiring simultaneous revascularization 3
• Critical consideration: Standard coronary physiological indices (FFR, resting indices) are not validated in AS populations, as the stenosis significantly affects coronary hemodynamics 2
• Maintain adequate preload during catheterization, as AS patients are preload-dependent and cannot compensate for volume depletion 3

When Imaging is Discordant

• If TTE and TEE are inadequate, cardiac MRI is reasonable as an alternative to assess VHD severity 1
• Cardiac CT can assess valve calcification to help distinguish truly severe AS from pseudosevere AS, particularly in low-flow, low-gradient scenarios 1

Management Implications

Symptomatic Patients with Chest Pain

• Aortic valve replacement is indicated for all symptomatic patients with severe AS, regardless of whether chest pain is from microvascular dysfunction or coexisting CAD 4
• The choice between TAVR and SAVR depends on surgical risk, with SAVR preferred for low-risk patients and TAVR appropriate for intermediate/high-risk patients 4
• Concomitant significant CAD requiring CABG favors surgical AVR over TAVR in appropriate candidates 3

Risk Stratification

• Exercise stress testing is crucial when symptom status is uncertain, with exercise-induced angina representing an abnormal test 1
• An increase in mean gradient with exercise ≥18 mmHg is associated with increased event rates 1

Key Clinical Pitfalls

• Do not attribute all chest pain to AS alone—systematic evaluation for CAD is mandatory, as both conditions frequently coexist 1, 3
• Avoid relying solely on symptom presence to gauge AS severity, as comorbidities substantially contribute to chest pain and dyspnea 5
• Recognize that coronary physiology assessment is unreliable in severe AS—standard FFR cutoffs may not apply, and valve replacement has variable effects on these measurements 2
• Maintain hemodynamic stability during any invasive procedures, avoiding vasodilators and ensuring adequate preload 3