CPT code 33864 identifies an open cardiothoracic operation to repair a thoracic aortic aneurysm by replacing the aortic root and proximal ascending aorta with a tube graft that incorporates a prosthetic valve, with reimplantation of the coronary arteries and use of cardiopulmonary bypass. This is a high-complexity, resource-intensive procedure performed in inpatient surgical settings and is clinically significant for management of life-threatening aortic root pathology.

Key payers represented in the coverage discussion include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a national-level overview of clinical context, typical sites of service, and common billing practices tied to this operative description. The publication also summarizes benchmarks and policy considerations relevant to high-acuity cardiothoracic procedures, highlights common modifiers used with this code, and outlines areas where coding and documentation influence claims processing. This content is intended to clarify the clinical scope of CPT code 33864, inform revenue cycle teams and clinical coders about the procedure’s billing context, and provide a concise reference for payers and healthcare administrators assessing coverage and payment for complex aortic root surgery.