What is the recommended work‑up and evaluation for aortic valve disease, including history, physical examination, imaging, stress testing, biomarkers, and surgical risk assessment?

Evaluation of Aortic Valve Disease

The evaluation of aortic valve disease requires a meticulous history and physical examination integrated with transthoracic echocardiography as the cornerstone diagnostic test, recognizing that no single test should be used in isolation for clinical decision-making. 1

History and Physical Examination

Critical Clinical Features to Assess

History:

• Symptom triad: Inquire specifically about exertional dyspnea, angina, and syncope/presyncope, as these indicate severe disease requiring intervention 2, 3
• Functional capacity: Patients may subconsciously curtail activities to avoid symptoms, making them appear asymptomatic 3
• Acute presentations: In suspected acute aortic regurgitation (AR), assess for sudden onset severe symptoms with poor hemodynamic tolerance despite less dramatic peripheral signs 2

Physical Examination:

• For aortic stenosis (AS): Palpate for dampened, delayed carotid upstroke (pulsus parvus et tardus); auscultate for late-peaking systolic ejection murmur radiating to carotids; assess for absent aortic component of S2 1
• For AR: Listen for diastolic murmur best heard at left sternal border with patient leaning forward after full expiration 2; assess for exaggerated arterial pulsations and widened pulse pressure (low diastolic blood pressure) 1, 2
• Arterial perfusion: Check for pulse differentials in all four extremities, as this may indicate aortic dissection with AR 1
• Cardiac tamponade signs: Assess for findings compatible with pericardial effusion in acute presentations 1

Common Pitfall

The physical examination establishes "pre-test probability" that guides interpretation of all subsequent testing. A clinician who follows echocardiographic results 100% of the time without integrating clinical findings is not properly performing their job. 1

Transthoracic Echocardiography (TTE)

TTE is the first-line and most important single diagnostic modality for valvular heart disease. 1

Essential Components of TTE Assessment

For Aortic Stenosis:

• Measure mean transvalvular gradient and calculate aortic valve area (AVA) using the continuity equation 1
• Assess left ventricular (LV) ejection fraction and dimensions 1
• Evaluate for low-flow, low-gradient states that may require dobutamine stress echocardiography 1

For Aortic Regurgitation:

• Severity grading: Use vena contracta width and continuous-wave Doppler assessment of pressure half-time 1
• Quantitative methods: Apply proximal isovelocity surface area (PISA) method when feasible, as it is less sensitive to loading conditions 1
• Aortic dimensions: Measure at four specific levels: annulus, sinuses of Valsalva, sino-tubular junction, and ascending aorta 1, 2
• LV assessment: Measure LV end-systolic diameter (LVESD) and end-diastolic diameter, indexed to body surface area (BSA) especially in patients with BSA ≤1.68 m² 1
• Mechanism determination: Classify leaflet motion abnormality (Type I: normal motion, Type II: excessive motion, Type III: restrictive motion) 1

Critical Pitfall

Never rely on color flow jet area alone to quantify regurgitation severity, as eccentric jets grossly underestimate severity when they impinge on atrial walls. 1 When echocardiographic findings conflict with clinical assessment (high pre-test probability), pursue additional investigation rather than accepting discordant results. 1

Transesophageal Echocardiography (TEE)

TEE is indicated when:

• TTE is non-diagnostic or of poor quality 1
• Valve-sparing intervention is being considered and detailed anatomic definition of cusps and ascending aorta is needed 1, 2
• Complex valve lesions require further diagnostic refinement 1

TEE is NOT indicated when TTE provides adequate diagnostic information, except intraoperatively during valve surgery. 1

Advanced Imaging

Cardiac MRI or CT

Indications for cross-sectional imaging:

• Aortic evaluation: When ascending aorta is not well visualized by echocardiography or when surgical indication may be based on aortic enlargement 1
• Specific populations requiring aortic imaging: Patients with bicuspid aortic valve, Marfan syndrome, or other connective tissue disorders 1
• Quantification: MRI can assess regurgitant volume and LV function when echocardiographic images are suboptimal 1
• Coronary assessment: CT angiography can simultaneously evaluate coronary anatomy and aortic pathology in elderly patients being considered for surgery 4

Stress Testing

Exercise Stress Testing

Indications:

• Apparently asymptomatic patients with severe AS: Carefully monitored exercise testing confirms truly asymptomatic status and assesses hemodynamic response to exercise 3
• Symptomatic status unclear: Helps unmask symptoms in patients who may have subconsciously curtailed activities 3

Important caveat: Current guidelines state that clinical decisions should not be based on changes in ejection fraction on exercise or stress echocardiography data, as these have not been adequately validated. 1

Dobutamine Stress Echocardiography

Primary indication: Confirm AS severity in low-flow, low-gradient states (both reduced and preserved ejection fraction) 1

Biomarkers

While not emphasized in the primary valvular guidelines reviewed, initial evaluation should include:

• Brain natriuretic peptide (BNP) for heart failure assessment 5
• Troponin if acute coronary syndrome is suspected 5
• Complete blood count, basic metabolic profile, and coagulation studies in acute presentations 5

Surgical Risk Assessment

Preoperative Coronary Evaluation

Coronary angiography is recommended:

• In elderly patients (particularly >70 years) with severe AR prior to surgical intervention 4
• Based on age, symptoms, and coronary risk factors 4
• To allow for combined coronary artery bypass grafting (CABG) and valve replacement when indicated 4

Risk Stratification Tools

The EuroSCORE provides operative mortality estimation and can be calculated at http://www.euroscore.org/calc.html 1

Follow-Up Intervals

Asymptomatic mild-to-moderate AR: Annual clinical review with echocardiography every 2 years 2

Asymptomatic severe AR:

• Initial follow-up at 6 months 2
• If LV diameter/ejection fraction shows significant changes or approaches intervention thresholds, continue 6-month intervals 2

Dilated aorta (especially with Marfan syndrome or bicuspid valve): Yearly echocardiography 2

Bicuspid valve with aortic root disease: Consider screening first-degree relatives with appropriate imaging 2

Integration of Findings

The key principle is that echocardiographic results must be interpreted using pre-test probability established by history and physical examination. 1 When discordance exists between clinical assessment suggesting severe disease and echocardiography showing mild-moderate disease, the clinician should:

1. Question technical factors (Doppler beam alignment, eccentric jets)
2. Pursue additional imaging (TEE, cardiac MRI)
3. Consider alternative explanations for symptoms

This integrative approach prevents both underestimation of severity (missing surgical candidates) and overestimation (subjecting patients to unnecessary intervention). 1