ICD-10-PCS Coding for AAOLCA Transconal Unroofing Procedure

Overview of AAOLCA and Transseptal Coronary Anatomy

Anomalous Aortic Origin of the Left Coronary Artery (AAOLCA) – Transseptal/Intraseptal Course

Diagnosis: Q24.5 – Malformation of coronary vessels

What is AAOLCA?

Anomalous Aortic Origin of the Left Coronary Artery (AAOLCA) is a congenital anomaly in which the left coronary artery arises from the right aortic sinus instead of the left sinus. In the transseptal/intraseptal variant, the artery takes an abnormal course behind or within the right ventricular outflow tract (RVOT) wall, often with an intramural segment. This can cause compression between the great vessels during exercise.

Clinical Risks Associated with AAOLCA

• Myocardial ischemia
• Sudden cardiac arrest or sudden cardiac death (especially in young athletes during exertion) AAOLCA is considered higher risk than the right-sided variant and is a leading cause of sudden cardiac death in young athletes.
  

Procedure Overview: Najm Transconal Unroofing Technique

Developed by Hani K. Najm, MD (Cleveland Clinic), the transconal unroofing procedure repairs AAOLCA with transseptal course. It includes right ventriculotomy, complete unroofing/exteriorization of the left coronary segment from its muscular bed (releasing compression), creation of a widened neo-ostium, separation from the compressive RVOT, and posterior elongation of the RVOT with an autologous pericardial patch. The coronary artery remains in situ.

Anatomic corrective repair — Do not use bypass codes (section 021).



ICD-10-PCS Coding Principles for Transconal Unroofing

• Coronary Arteries: Code by number of sites treated (usually “One Artery”). Do not name branches (B4.4).
• Approach: Always Open (0).
• Unroofing of anomalous coronary artery (intramural/transseptal segment) to remove constriction and improve the ostium → Root operation Release.
• RVOT patch: Supplement
• Device: Z (No Device) for coronary unroofing; tissue substitute for RVOT patch.

Procedure Components and ICD-10-PCS Code Assignment

Coding Decision Guide for AAOLCA Repair

1. Transseptal coronary segment unroofed to release constriction? → Release Coronary Artery (02N0xZZ).
2. Right ventriculotomy + RVOT patch elongation? → Add Supplement Right Ventricle (02UK0xZ).
3. Patch material:
4. Autologous pericardium → Autologous Tissue Substitute (7)
5. Bovine pericardium → Nonautologous Tissue Substitute (K)
6. Multiple coronary sites? Code to highest number treated.

Additional Coding and Documentation Tips

• Cardiopulmonary bypass and sternotomy are integral (do not code separately).
• Query surgeon for: number of coronary sites, exact patch material, and confirmation of “in situ” unroofing.
• Differs from standard intramural unroofing due to transconal exposure and RVOT reconstruction.
• AHA Coding Clinic (2nd Quarter 2019, pp. 13-14) explicitly assigns Release for unroofing of anomalous coronary artery to remove constriction and improve the ostium.



Tracy Blevins is a Senior Consultant in Quality Auditing at UASI, with 14+ years of inpatient medical coding and health information management experience. As a Registered Health Information Administrator that also holds AHIMA’s Auditing Inpatient Coding Microcredential, she shares practical, detail-driven coding tips to help clinicians and coders strengthen documentation, accuracy, and compliance. 

Works Cited

Najm, H. K., & Ahmad, M. (2019). Transconal unroofing of anomalous left main coronary artery from right sinus with transseptal course. Annals of Thoracic Surgery. Available at: https://www.annalsthoracicsurgery.org/article/S0003-4975(19)30694-0/fulltext

Najm, H. K., et al. (2021). Early outcomes of transconal repair of transseptal anomalous aortic origin of left coronary artery. Annals of Thoracic Surgery. Available at: https://pubmed.ncbi.nlm.nih.gov/32822667/

Najm, H. K., et al. (2023). Surgical pearls of the transconal unroofing procedure—modifications and midterm outcomes. Annals of Thoracic Surgery. Available at: https://www.annalsthoracicsurgery.org/article/S0003-4975(22)00641-5/fulltext

Cleveland Clinic. (2023). New pearls and outcomes for transconal unroofing procedure. Consult QD. Available at: https://consultqd.clevelandclinic.org/new-pearls-outcomes-for-transconal-unroofing-procedure

American Hospital Association. (2019). Unroofing of anomalous coronary artery. AHA Coding Clinic for ICD-10-CM/PCS, Second

Quarter 2019, pp. 13–14. Available at: https://www.findacode.com/newsletters/aha-coding-clinic/icd/unroofing-anomalous-coronary-artery-I062020.html