CABG Coding: Arterial Codes, Venous Add-Ons, and the Harvest Rules
Coronary bypass coding is structured unlike anything else in surgery: the codes are organized around graft material and count, and half the family only exists as add-ons.
The two-part structure
- Arterial grafts (33533–33536): select by the number of arterial grafts (one, two, three, four or more). A single LIMA-to-LAD is 33533.
- Venous grafts with arterial (33517–33523): when any arterial graft is performed, vein grafts are reported only with these combined add-on codes — never with the standalone venous family.
- Vein-only CABG (33510–33516): reserved for the now-uncommon case with no arterial graft at all.
So a three-vessel CABG with LIMA plus two saphenous grafts is 33533 + 33518 — not three separate codes.
Harvest: bundled, except endoscopic vein
Open vein and arterial harvest are included in the bypass codes. Endoscopic vein harvest is the exception, reported with its own add-on (+33508).
The rest of the session
Cardiopulmonary bypass is inherent to on-pump codes. A valve procedure at the same session is separately reportable alongside CABG. Redo sternotomy carries its own add-on (+33530). Add-on codes are modifier -51 exempt — payers reduce them by formula, not by modifier.
Clinical Capture parses the graft inventory from the operative note — how many arterial, how many venous, how harvested — and assembles the base-plus-add-on structure with official CMS work RVUs for each line.
This article is educational and not coding, billing, or legal advice. Always verify codes and values against the current CPT®, ICD-10-CM, and CMS Physician Fee Schedule, follow NCCI edits and payer policy, and confirm with a certified coder before submitting a claim. Document only work that was actually performed.