What is the recommended approach for monitoring patients with aortic regurgitation?

Monitoring Aortic Regurgitation

Surveillance Intervals Based on Severity

For patients with aortic regurgitation, monitoring frequency should be stratified by disease severity: mild AR requires echocardiography every 3-5 years, moderate AR every 1-2 years, and severe asymptomatic AR every 6-12 months. 1, 2, 3

Mild Aortic Regurgitation

• Clinical evaluation and transthoracic echocardiography (TTE) every 3-5 years 1, 2
• Defined as vena contracta <0.3 cm, regurgitant volume <30 mL/beat, regurgitant fraction <30%, and effective regurgitant orifice <0.10 cm² 2

Moderate Aortic Regurgitation

• TTE surveillance every 1-2 years 1, 2, 3
• Annual clinical assessment to identify symptom development 3
• Defined as vena contracta 0.3-0.6 cm, regurgitant volume 30-59 mL/beat, regurgitant fraction 30-49%, and ERO 0.10-0.29 cm² 2

Severe Aortic Regurgitation

• TTE every 6-12 months for asymptomatic patients with normal LV function 1, 2
• More frequent monitoring (every 3-6 months) is mandatory if there is evidence of progressive LV dilatation or declining ejection fraction 1, 3
• Defined as vena contracta >0.6 cm, regurgitant volume ≥60 mL/beat, regurgitant fraction ≥50%, and ERO ≥0.3 cm² 1, 3

Key Parameters to Monitor

Left Ventricular Function and Dimensions

Serial assessment of LV ejection fraction and dimensions is critical, as these determine surgical timing. 1

• Monitor LV end-systolic diameter (LVESD): Surgery is indicated when LVESD >50 mm or indexed LVESD >25 mm/m² 1
• Monitor LV end-diastolic diameter (LVEDD): Progressive dilatation >65 mm warrants closer surveillance 1
• Track LV ejection fraction: Decline to ≤50-55% triggers surgical referral even in asymptomatic patients 1, 3
• LV end-systolic diameter index >20 mm/m² is associated with increased mortality and should prompt consideration for intervention when surgical risk is low 1

Aortic Root Assessment

• Measure aortic root and ascending aorta dimensions at multiple levels at initial diagnosis 1
• In bicuspid aortic valve patients with aortic diameter >40 mm, perform TTE after 1 year, then every 2-3 years if stable 1
• Use cardiac CT or CMR when aortic diameter exceeds 45 mm or when TTE measurements are discrepant 1

Advanced Imaging Modalities

When to Use Cardiac Magnetic Resonance (CMR)

CMR should be employed when TTE is non-diagnostic or when there is discordance between clinical findings and echocardiographic severity. 1

• CMR is the reference standard for quantifying LV volumes and systolic function 1
• Regurgitant fraction and regurgitant volume by CMR provide prognostic information and may reclassify AR severity determined by TTE 1
• CMR of the entire thoracic aorta every 3-5 years is recommended in patients with bicuspid aortic valve-associated aortopathy 1

Transesophageal Echocardiography (TEE)

• TEE is indicated when TTE images are suboptimal for assessing AR severity 1
• Essential for intraoperative assessment during valve procedures 1
• Useful for evaluating valve morphology and feasibility of valve repair 1

Clinical Assessment Components

Symptom Surveillance

Exercise testing should be performed in sedentary patients or those with equivocal symptoms to objectively assess functional capacity. 1

• Monitor for development of dyspnea, angina, or heart failure symptoms 1
• Symptoms indicate need for surgical intervention regardless of LV function 2, 3
• Patients with severe symptoms (NYHA class III-IV) have excess mortality of 24.6% yearly 4

Blood Pressure Management

• Treat hypertension (systolic BP >140 mmHg) with vasodilators that do not slow heart rate 3
• Use ACE inhibitors or dihydropyridine calcium channel blockers (e.g., nifedipine) 2, 3
• Avoid beta-blockers as they prolong diastole and increase regurgitant volume 3

High-Risk Features Requiring Intensified Monitoring

Accelerate monitoring frequency to every 3-6 months when any of the following develop: 1, 3

• Progressive LV dilatation on serial imaging 1
• Declining LVEF, particularly approaching 50-55% 3
• Development of any cardiac symptoms 1
• LVESD approaching 50 mm or indexed LVESD approaching 25 mm/m² 1
• Holodiastolic flow reversal in descending aorta 3

Special Populations

Bicuspid Aortic Valve

• Screen first-degree relatives with TTE for BAV and aortic dilatation 1
• More frequent monitoring due to higher risk of progression 2
• Annual TTE monitoring of aortic root/ascending aorta 1

Mixed Aortic Valve Disease

• Monitor every 6 months when AR coexists with aortic stenosis, as half of patients become symptomatic within 1 year 1
• Moderate mixed aortic valve disease has poorer prognosis than moderate AR or AS alone 1

Common Pitfalls to Avoid

• Do not rely on a single echocardiographic parameter to determine AR severity; use an integrative, multi-parametric approach 2, 5
• Do not miss associated aortic root or ascending aorta dilation, which requires more frequent monitoring 2
• Do not delay surgery in asymptomatic patients with LVEF <55% or LVESD >50 mm, as these patients have excess mortality (5.8-7.8% yearly) 4
• Recognize that symptoms may not correlate with objective ventricular dysfunction due to insidious disease progression 6