ICD-10-CM Coding for Suspected Bicuspid Aortic Valve
For a suspected bicuspid aortic valve that has not yet been confirmed by imaging, use ICD-10-CM code Q23.1 (Congenital insufficiency of aortic valve) or Q23.0 (Congenital stenosis of aortic valve) if there are associated valve dysfunction symptoms, or use a symptom-based code until imaging confirmation is obtained—do not use the definitive BAV code Q23.81 until echocardiographic or CT confirmation demonstrates two cusps with two commissures.
Coding Strategy Before Confirmation
Until October 2024, no specific ICD-10 code existed for bicuspid aortic valve 1. The code Q23.81 was introduced specifically for confirmed BAV, but this requires imaging documentation showing:
- Two commissures visible on short-axis view (not three)
- Two cusps forming an elliptical or "fish-mouth" opening in systole 2
- Systolic doming of the fused cusp on long-axis view 3
Before Imaging Confirmation, Code Based On:
If clinical suspicion only:
- Use symptom codes (e.g., R07.9 for chest pain, R06.02 for dyspnea)
- Consider Z82.49 (Family history of ischemic heart disease and other diseases of circulatory system) if there's a family history, since 9% of BAV patients have affected family members 4
If there are associated findings:
- Q23.0: Congenital stenosis of aortic valve (if stenotic features suspected)
- Q23.1: Congenital insufficiency of aortic valve (if regurgitation suspected)
- I35.0 or I35.1: For acquired stenosis or regurgitation if age >65 years (when tricuspid calcific disease more likely) 2
Critical Diagnostic Pitfalls
Do not code as confirmed BAV (Q23.81) based on:
- Diastolic images alone—these can mimic three cusps when a raphe is present 2
- Asymmetric closure line or diastolic prolapse on long-axis views—these are suggestive but not diagnostic 2
- Heavy calcification obscuring cusp number—this is common in adults and makes TTE unreliable 2
Transthoracic echocardiography has only 79.7% sensitivity for BAV diagnosis (95% CI: 71.6-86.0%), while retrospectively ECG-gated CT achieves 95.5% sensitivity 5. If TTE is inconclusive due to calcification or poor windows, obtain CT before coding definitively.
When to Confirm and Code Q23.81
Gold standard imaging criteria 2, 3:
- Short-axis systolic view showing exactly two commissures
- Elliptical systolic orifice (not stellate-shaped as in tricuspid valves)
- Absence of a third commissure throughout the cardiac cycle
Alternative confirmation:
- Retrospectively ECG-gated cardiac CT (95.5% sensitivity, 96% specificity) 5
- Transesophageal echocardiography if TTE inadequate 2
- Intraoperative or pathological confirmation 3
Associated Conditions Requiring Surveillance
Once BAV is confirmed, all patients require imaging of both the aortic root and ascending aorta for dilatation 4. This is a Class I recommendation because:
- 20% have concurrent ascending aortic aneurysms 4
- 15% of acute aortic dissections occur in BAV patients 4
- 12.5% experience dissection at diameters <5 cm 4
First-degree relatives should be screened with imaging for BAV and aortic disease (Class I recommendation) 4.
Documentation Requirements
For definitive Q23.81 coding, ensure the medical record contains: