Management of Aortic Regurgitation
Surgical aortic valve replacement is indicated for all symptomatic patients with severe AR regardless of left ventricular function, and for asymptomatic patients when LVEF falls below 55% or when LV end-systolic diameter exceeds 50 mm (or 25 mm/m² indexed). 1
Diagnosis and Severity Assessment
Echocardiography is the primary diagnostic modality for AR, defining etiology and grading severity. 1 Key parameters for severe AR include:
- Vena contracta >0.6 cm 1
- Effective regurgitant orifice area (EROA) ≥0.3 cm² 1
- Regurgitant volume ≥60 mL/beat 1
- Holodiastolic flow reversal in descending aorta 1
- LV end-systolic diameter (LVESD) >50 mm or >25 mm/m² 1
Use an integrative, multi-parametric approach rather than relying on a single parameter, as no single measure is sufficient to determine AR severity. 2, 3 Cardiac magnetic resonance imaging can complement echocardiography when diagnostic uncertainty exists, particularly for assessing biventricular volumes, systolic function, and regurgitant fraction. 1
Indications for Surgical Intervention
Symptomatic Severe AR
Operate immediately on all symptomatic patients with severe AR, regardless of LV function. 1 This includes patients with dyspnea, angina, or heart failure symptoms. Delaying surgery in symptomatic patients significantly worsens postoperative survival. 1
Asymptomatic Severe AR
Surgery is indicated when any of the following develop:
- LVEF ≤55% (some guidelines use <50% as threshold) 1, 2
- LV end-systolic diameter >50 mm or >25 mm/m² 1
- LV end-diastolic diameter ≥75 mm 1
- Progressive LV dilatation on serial imaging 1
Do not delay surgery once these thresholds are reached, as prompt referral results in significantly better postoperative outcomes compared to delayed intervention. 1 Patients with asymptomatic severe AR and normal LV function have good prognosis with conservative management, with only 12% requiring surgery at 5 years and 24% at 10 years. 4
Concurrent Cardiac Surgery
Patients with severe AR (symptomatic or asymptomatic) undergoing CABG, other valve surgery, or ascending aorta surgery must have concomitant aortic valve surgery. 1, 5 Consider concomitant valve surgery for moderate AR during cardiac operations based on age, AR etiology, and possibility of valve repair. 2
Aortic Root Disease
When AR coexists with aortic root dilatation ≥5.0 cm, perform both AVR and aortic root reconstruction regardless of AR severity. 1 Some centers recommend surgery at 4.5 cm or when growth rate exceeds 0.5 cm/year, particularly in centers with established expertise. 1
Preoperative Coronary Evaluation
Perform coronary angiography in elderly patients (particularly >70 years) with severe AR prior to surgical intervention. 5 This allows for combined CABG and AVR when indicated. 5 CT imaging can evaluate both coronary anatomy and aortic pathology simultaneously as an alternative approach. 5
Medical Management
Asymptomatic Patients with Normal LV Function
No specific medical therapy is required for asymptomatic patients with mild to moderate AR and normal LV function. 2 However, for asymptomatic severe AR with normal LV function, vasodilators (particularly nifedipine) may prolong the compensated phase and delay AVR, though evidence is limited. 6
Hypertension Management
Treat hypertension with vasodilators, preferably ACE inhibitors or dihydropyridine calcium channel blockers. 2, 6 ACE inhibitors are particularly useful in hypertensive patients with AR. 6
Symptomatic Patients or LV Dysfunction
Optimal guideline-directed medical therapy for heart failure is indicated when surgery is not feasible or for persistent heart failure/hypertension post-surgery. 1 Vasodilators should be considered as short-term treatment before surgery if severe heart failure is present, or long-term if AVR is contraindicated. 6
Special Populations
Beta-blockers may slow aortic dilatation rate and delay surgery in AR associated with aortic root disease. 6 They may also improve cardiac performance by reducing LV volume and mass in patients with impaired LV function after AVR. 6
Surveillance and Follow-up
Severe asymptomatic AR requires 6-12 monthly follow-up with echocardiography. 1 If LVEF falls or LV size increases, repeat imaging every 3-6 months. 1, 2
Factors predicting more rapid progression include bicuspid aortic valve, rheumatic disease, and aortic root dilation. 2 Baseline end-systolic diameter >50 mm and ejection fraction <60% independently predict development of symptoms or LV dysfunction. 4
Postoperative Management
Obtain baseline echocardiogram within the first few weeks after AVR to assess LV size and function and serve as comparison for future studies. 1 The reduction in LV end-diastolic dimension (which occurs within 1-2 weeks) is a better predictor of subsequent LV function than early ejection fraction changes. 1 Use LV volumes rather than diameters to assess reverse remodeling post-AVR, as diameter-based measurements incorrectly identify reverse remodeling in 17% of patients. 7
Critical Pitfalls to Avoid
Do not operate on asymptomatic patients with normal systolic function merely because of LV dilatation if end-diastolic dimension is <75 mm or end-systolic dimension is <55 mm. 1 However, do not delay surgery in high-risk groups: patients with even mild (class II) symptoms have 6.3% yearly mortality, asymptomatic patients with LVEF <55% have 5.8% yearly mortality, and those with indexed end-systolic diameter ≥25 mm/m² have 7.8% yearly mortality. 8 Patients with severe symptoms have 24.6% yearly mortality with conservative management. 8
Always assess for associated aortic root or ascending aorta dilation, as this may require more frequent monitoring or alter surgical indications. 2