Q25.42 Hypoplasia of aorta

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis. Exempt from present-on-admission (POA) reporting.

Applies from Q25.4 Other congenital malformations of aorta

Excludes1 (never code together)

• hypoplasia of aorta in hypoplastic left heart syndrome (Q23.4)

MS-DRG index

Defines the logic of DRG(s) 306-307 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 747.29 Other anomalies of aorta (approximate)

Code annotations containing back-references to Q25.42

Back-references to Q25

• Code Also: I27.21 Secondary pulmonary arterial hypertension ("congenital heart disease (Q20-Q28)")
• Type 2 Excludes: P29 Cardiovascular disorders originating in the perinatal period ("congenital malformations of the circulatory system (Q20-Q28)")
• Code Also: Z71.87 Encounter for pediatric-to-adult transition counseling ("congenital malformations of the circulatory system (Q20-Q28)")

Diagnosis Index entries for Q25.42

• Hypoplasia, hypoplastic › aorta, aortic
• Malformation (congenital) › aorta › hypoplasia

Nearby codes

• Q25.29 Other atresia of aorta
• Q25.3 Supravalvular aortic stenosis
• Q25.4 Other congenital malformations of aorta
• Q25.40 Congenital malformation of aorta unspecified
• Q25.41 Absence and aplasia of aorta
• Q25.42 Hypoplasia of aorta (this code)
• Q25.43 Congenital aneurysm of aorta
• Q25.44 Congenital dilation of aorta
• Q25.45 Double aortic arch
• Q25.46 Tortuous aortic arch
• Q25.47 Right aortic arch