E645 – Off pump coronary artery bypass grafting
OHIP Surgical Assists Code — CARDIOVASCULAR SURGICAL PROCEDURES · Schedule of Benefits
This code is used as an add-on for off-pump coronary artery bypass grafting procedures (`R742, R743`).
Claiming Instructions:
- Surgeon: Claims E645 with suffix 'A' as a flat-fee add-on to the primary surgical procedure.
- Surgical Assistant: Claims E645B instead of the assistant fee for the primary procedure (e.g., `R742B`). The fee is calculated based on 24 basic units plus time units.
- Anaesthesiologist: Claims E645C instead of the anaesthesia fee for the primary procedure (e.g., `R742C`). The fee is calculated based on 40 basic units plus time units, as this code replaces the basic units for the primary procedure.
Additional Rules:
- Second Assistant: Payment for a second surgical assistant is permitted for this procedure without requiring special authorization from a medical consultant.
When to Use
- Use E645 as a flat-fee add-on for the surgeon when performing off-pump coronary artery bypass grafting via R742 or R743.
- Use E645B for the surgical assistant instead of R742B or R743B to correctly apply the 24 basic unit calculation.
- Use E645C for the anaesthesiologist instead of R742C or R743C to correctly apply the 40 basic unit calculation.
Common Pitfalls
- Claiming the standard assistant (R742B/R743B) or anaesthesia (R742C/R743C) codes alongside the primary procedure instead of the E645 series, which leads to automatic rejection or recovery.
- Failing to document precise start and end times in the medical record, which is mandatory for the time-unit calculations required for E645B and E645C.
- Attempting to bill E645 as a standalone code; it must be submitted on the same claim as the primary coronary artery repair procedure (R742 or R743).
Billing Tips
- Ensure the surgical assistant and anaesthesiologist explicitly use the E645 suffix codes to trigger the correct basic unit values, as these replace the standard units associated with the primary procedure.
Effective: April 1, 2025
Q. Cardiovascular Surgical Procedures
CARDIOVASCULAR SURGICAL PROCEDURES
Surgical
Cardiovascular Surgical Procedures, Surgical Assistants' Services, Anaesthesiologists' Services
For the anaesthesiologist, when off-pump coronary artery bypass grafting is rendered, submit claim using E645C with 40 basic units plus time units, instead of R742C or R743C. See General Preamble .
For the surgical assistant, when off-pump coronary artery bypass grafting is rendered, submit claim using E645B with 24 basic units plus time units, instead of R742B or R743B.
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