Which ICD‑10‑CM diagnosis code should be used for a confirmed bicuspid aortic valve and for a screening encounter due to family history?

ICD-10-CM Coding for Bicuspid Aortic Valve

For a confirmed bicuspid aortic valve, use ICD-10-CM code Q23.1 (Congenital insufficiency of aortic valve) or Q23.0 (Congenital stenosis of aortic valve) depending on the valve dysfunction present, or Q23.8 (Other congenital malformations of aortic and mitral valves) if the bicuspid valve is documented without significant stenosis or regurgitation.

Coding for Confirmed Bicuspid Aortic Valve

The primary diagnosis code depends on the clinical presentation:

• Q23.1 - Use when bicuspid aortic valve presents with aortic regurgitation/insufficiency
• Q23.0 - Use when bicuspid aortic valve presents with aortic stenosis
• Q23.8 - Use for documented bicuspid aortic valve without significant valvular dysfunction (most appropriate for isolated BAV)

Important coding note: Bicuspid aortic valve is classified as a congenital heart disease of "mild" complexity according to both AHA/ACC and ESC guidelines 11. The condition affects 1-2% of the general population and represents the most common congenital cardiac abnormality 2223.

Coding for Family History Screening Encounter

For a screening encounter due to family history of bicuspid aortic valve, use Z82.49 (Family history of ischemic heart disease and other diseases of the circulatory system) as the primary code, with Z13.6 (Encounter for screening for cardiovascular disorders) as a secondary code.

Rationale for Family Screening Codes

Guidelines strongly support family screening for BAV 222222. Specifically:

• First-degree relatives of patients with BAV should be evaluated for the presence of bicuspid aortic valve and asymptomatic thoracic aortic disease (Class I recommendation, Level of Evidence C) 222
• BAV can be inherited as an autosomal dominant condition, with approximately 9% of patients having family members with BAV 22
• The prevalence of BAV among screened relatives is 7.3% overall, with 23.6% of families having at least one affected relative 4

Additional Coding Considerations

If Aortic Dilatation is Present

When bicuspid aortic valve is associated with aortic root or ascending aortic dilatation (BAV aortopathy):

• Add I77.810 (Thoracic aortic ectasia) or I71.01 (Dissection of thoracic aorta) if dissection present
• Approximately 40% of BAV patients in referral centers have thoracic aortic dilation 3
• 20% of patients undergoing BAV surgery have concurrent ascending aortic aneurysms requiring repair 22

Common Pitfalls to Avoid

1. Don't use I35.x codes (nonrheumatic aortic valve disorders) for congenital bicuspid aortic valve - these are for acquired conditions
2. Don't overlook associated conditions - BAV frequently occurs with coarctation of the aorta, Turner syndrome, or thoracic aortic aneurysm 222
3. Document valve morphology specifically - the 2021 international consensus provides detailed classification systems that should be referenced in clinical documentation 5

For Screening Documentation

When documenting family screening encounters, note that:

• Screening uptake among at-risk siblings is only 38.7% 6
• Combined recurrence of BAV and thoracic aortic aneurysm in screened siblings is 15.3% 6
• Aortic dilatation occurs in 9.4% of screened relatives, including 7% of those with tricuspid valves 4

The recommendation for screening should be explicitly documented in the cardiology note, as this significantly increases screening uptake (p=0.03) 6.