When to refer patients with aortic stenosis or aortic regurgitation for surgery?

When to Refer for Surgery: Aortic Stenosis and Aortic Regurgitation

Aortic Stenosis - Surgical Referral Indications

Refer all symptomatic patients with severe aortic stenosis (AS) for surgical evaluation immediately, regardless of left ventricular function, as this is a Class I indication with survival comparable to age-matched populations after intervention. 1

Symptomatic Severe AS (Stage D)

• Any symptoms (angina, dyspnea, syncope/presyncope) with severe AS mandate surgical referral 1
• Symptomatic patients have 1-year survival of only 66-69% without surgery versus 94% with intervention 2
• Operative mortality is approximately 1-2% for both symptomatic and asymptomatic patients 3

Asymptomatic Severe AS - Refer When:

LVEF ≤55% (Stage C2):

• Immediate surgical referral indicated if no other cause for systolic dysfunction identified 1
• This represents decompensation and warrants intervention before further deterioration 1

Severe LV Enlargement with Normal LVEF:

• LVESD >50 mm OR indexed LVESD >25 mm/m² (Class IIa recommendation) 1
• These thresholds indicate impending decompensation despite preserved ejection fraction 1

Progressive LV Changes (Class IIb, Low Surgical Risk Only):

• LVEF declining to 55-60% on ≥3 serial studies, OR
• LVEDD increasing to >65 mm on serial imaging 1
• Requires documented progression over time, not single measurement 1

Undergoing Other Cardiac Surgery:

• Severe AS (Stage C or D): Class I indication for concurrent AVR 1
• Moderate AS (Stage B): Class IIa indication for concurrent AVR 1

Special Considerations for AS:

Asymptomatic patients requiring major noncardiac surgery:

• Elective noncardiac surgery: AVR (TAVR or SAVR) is appropriate before proceeding 1
• Emergency noncardiac surgery: Can proceed with careful hemodynamic monitoring, though risk of complications exists 1, 4
• Selected patients with severe AS can undergo noncardiac surgery with ~10% mortality risk when AVR refused or contraindicated 1, 4

Exercise Testing Role:

• Consider in truly asymptomatic patients to unmask symptoms or abnormal hemodynamic response 5
• Positive exercise test (symptoms, hypotension, or inadequate BP response) upgrades to symptomatic status requiring referral 5

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Aortic Regurgitation - Surgical Referral Indications

Refer all symptomatic patients with severe AR for surgery regardless of LV function, as symptoms indicate Stage D disease with Class I indication for intervention. 1

Symptomatic Severe AR (Stage D)

• Any symptoms attributable to AR mandate surgical referral 1
• Surgery indicated regardless of LVEF 1
• Symptoms indicate decompensation requiring intervention 1

Asymptomatic Severe AR - Refer When:

LVEF ≤55% (Stage C2):

• Class I indication for surgery if no other cause for systolic dysfunction 1
• Critical threshold as LVEF may overestimate true LV performance in AR 1
• Even mildly reduced LVEF signals reduced ventricular reserve in AR 1

Severe LV Enlargement with Normal LVEF (Stage C2):

• LVESD >50 mm OR indexed LVESD >25 mm/m² (Class IIa recommendation) 1
• LVEDD >70 mm or indexed LVESD >25 mm/m² for small stature patients 1
• These dimensions predict adverse outcomes without intervention 1

Progressive LV Changes (Class IIb, Low Surgical Risk):

• LVEF declining to 55-60% on ≥3 serial studies, OR
• LVEDD increasing to >65 mm on serial imaging 1
• Requires low surgical risk and documented progression 1

Undergoing Other Cardiac Surgery:

• Severe AR (Stage C or D): Class I indication for concurrent valve surgery 1
• Moderate AR (Stage B): Class IIa indication for concurrent cardiac/aortic surgery 1

Important Caveats for AR:

TAVI is contraindicated (Class III: Harm):

• Do not perform TAVI in isolated severe AR patients who are surgical candidates 1
• SAVR remains standard of care; valve-sparing procedures may be possible in selected patients 1

Distinguish primary from secondary AR:

• Mild-moderate AR secondary to LV dilatation differs from primary severe AR causing LV dysfunction 1
• Primary severe AR requires intervention based on above criteria 1

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Moderate Valvular Disease

Moderate AS or AR alone does not warrant isolated valve surgery, but consider concurrent intervention during other cardiac operations. 1, 6

Moderate AR Surveillance:

• Echocardiography every 1-2 years to detect progression 6
• Clinical assessment yearly for symptom development 6
• More frequent imaging (every 3-6 months) if significant LVEF changes or progressive LV dilatation 6

Moderate Disease During Other Surgery:

• Class IIa recommendation for concurrent valve surgery during CABG, other valve surgery, or aortic surgery 1, 6
• Decision should account for AR etiology, patient age, progression trajectory, and repair possibility 6

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Critical Pitfalls to Avoid

Do not delay referral in symptomatic patients:

• Only 41-52% of patients with severe AS actually undergo surgery despite indications 2
• Unoperated symptomatic patients have 1-year mortality of 66-74% 7, 2
• Absence of surgical treatment is the most important risk factor for mortality in severe AS 3

Do not rely solely on gradient in AS:

• Low-gradient severe AS exists and requires comprehensive evaluation 1
• Patients may be referred more readily with high gradients than low valve area alone 2

Do not use vasodilators carelessly in severe AS:

• ACE inhibitors, ARBs, and other vasodilators can cause substantial hypotension 1
• Use with extreme caution; optimization should not delay surgical decision-making 1

Do not confuse symptoms:

• Patients with heart failure symptoms may be referred less often than those with angina 2
• All symptom types (angina, dyspnea, syncope) equally mandate referral in severe disease 1, 2

Recognize that "asymptomatic" may be misleading:

• 79-87% of patients meeting surgical criteria actually have symptoms when carefully assessed 2
• Exercise testing can unmask occult symptoms in reportedly asymptomatic patients 5