What is the management approach for calcified degenerative aortic stenosis in the absence of a bicuspid aortic valve?

Management of Calcified Degenerative Aortic Stenosis (Non-Bicuspid)

For calcified degenerative aortic stenosis in the absence of a bicuspid valve, management follows standard valvular heart disease guidelines with aortic valve replacement (AVR) indicated for symptomatic severe stenosis or asymptomatic severe stenosis with left ventricular dysfunction (LVEF <50%). 1, 2

Diagnostic Evaluation

Echocardiography is the primary diagnostic modality to define valve anatomy, measure stenosis severity, and evaluate left ventricular response to chronic pressure overload 3, 2. Severe aortic stenosis is defined by:

• Aortic velocity ≥4.0 m/s
• Mean gradient ≥40 mm Hg
• Valve area ≤1.0 cm² 2

Cardiac catheterization for hemodynamic measurements is NOT recommended when noninvasive tests are adequate and concordant with clinical findings 1. However, catheterization IS recommended when noninvasive tests are inconclusive or discrepant with clinical findings in symptomatic patients 1.

Coronary angiography is recommended before AVR in patients at risk for coronary artery disease 1.

Medical Management (Asymptomatic Patients)

There are no medical treatments proven to prevent or delay disease progression in calcific aortic stenosis 1. A prospective randomized trial failed to demonstrate benefit of atorvastatin in reducing progression over 3 years in patients with moderate-to-severe AS 1.

Hypertension should be treated with pharmacotherapy starting at low doses and gradually titrating upward 4. RAS blockade (ACE inhibitors or ARBs) may be advantageous due to potentially beneficial effects on left ventricular fibrosis and improved effort tolerance 4.

Avoid excessive blood pressure reduction that could compromise coronary perfusion 4.

Surveillance Intervals

Clinical and echocardiographic surveillance intervals based on severity 2:

• Mild AS (Vmax 2.0-2.9 m/s): Every 3-5 years
• Moderate AS (Vmax 3.0-3.9 m/s): Every 1-2 years
• Severe AS (Vmax ≥4.0 m/s): Every 6-12 months

Exercise Testing

Exercise testing is contraindicated in symptomatic severe AS but can be valuable in asymptomatic patients 1. An abnormal hemodynamic response (hypotension or failure to increase blood pressure) is a poor prognostic finding 1. Exercise testing brought out symptoms in 29% of patients considered asymptomatic, and these patients developed spontaneous symptoms in 51% over the next year 1.

Patients with moderate-to-severe AS should avoid competitive sports involving high dynamic and static muscular demands 1.

Indications for Aortic Valve Replacement

Class I Indications (Definitive)

AVR is recommended for 1:

• Symptomatic patients with severe AS (angina, syncope, heart failure)
• Asymptomatic patients with severe AS and LVEF <50% (unless due to other causes)
• Patients with severe AS undergoing other cardiac surgery (CABG, ascending aorta surgery, other valve surgery)

Symptomatic patients require urgent surgery as they have a 1-year mortality rate up to 50% without intervention 2. Medical treatment for heart failure is reserved only for non-operable patients 1.

Class IIa Indications (Reasonable)

AVR should be considered for 1:

• Asymptomatic severe AS with fall in blood pressure below baseline during exercise testing
• Asymptomatic severe AS with moderate-to-severe calcification and peak velocity progression ≥0.3 m/s/year
• Severe AS with low gradient (<40 mmHg) and LV dysfunction WITH contractile reserve

Valve Selection and Approach

For patients aged >65 years, bioprosthetic valves are recommended 3.

Transcatheter aortic valve implantation (TAVI) versus surgical AVR (SAVR) 2:

• Age ≤65 years: SAVR recommended
• Age 66-79 years: SAVR or TAVI (shared decision-making)
• Age ≥80 years or surgical mortality ≥8%: TAVI recommended

TAVI is associated with decreased hospitalization length, more rapid return to normal activities, and less pain compared with SAVR 2. Ten-year mortality is similar between approaches (62.7% TAVI vs 64.0% SAVR in patients >70 years with low surgical risk) 2.

Poor Prognostic Indicators

Factors associated with poor outcomes after AVR include 3:

• Low-flow low-gradient aortic stenosis
• Severe ventricular fibrosis
• Oxygen-dependent lung disease
• Frailty
• Advanced renal dysfunction
• High comorbidity score

In the natural history study, all four deaths occurred in patients with aortic valve area <0.7 cm² and abnormal exercise test (1.2% annual mortality rate) 1.

Key Distinction from Bicuspid Valve Disease

Unlike bicuspid aortic valve disease, calcified degenerative (tricuspid) AS is not amenable to balloon valvuloplasty 1. Calcification of the valve necessitates valve replacement rather than repair 1. The disease process represents active cellular mechanisms with regulated bone formation rather than passive calcium deposition 5.