CPT code 35537: Aortoiliac bypass, vein conduit, iliac outflow2026 Medicare rate & RVUs in Illinois
Reports an aortic-to-iliac arterial bypass using a vein graft, typically to restore blood flow in a patient with aortoiliac occlusive disease.
CMS doesn’t publish an office rate for 35537 in Illinois.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
Your location
On this page 9 sections
What 35537 covers
This code represents an open arterial bypass from the aorta to an iliac artery using a vein conduit. Vascular surgeons typically perform it in an operating room to route blood around diseased or obstructed aortoiliac segments. The operative report should identify the bypass origin and outflow, the vein conduit, and the condition being treated so the documented reconstruction supports this code rather than a bypass ending in the femoral arteries or involving both iliac arteries.
Report the code for the aorta-to-iliac configuration, not for each anastomosis or each side as a separate service. The major-surgery global period includes the day-before preoperative visit and 90 days of related postoperative care. When multiple procedures are performed in the same session, the highest-valued procedure is paid in full and other procedures are subject to the standard 50% multiple-procedure reduction. Modifier 50 is inappropriate for this code. An assistant at surgery may be paid; co-surgeon payment requires supporting documentation, and team surgery is not permitted.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 35537 pays more and less in Illinois
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
| Payment locality | Office | Facility |
|---|---|---|
| Chicago, IL | Unavailable | $2,354.71 |
| East St. Louis, IL | Unavailable | $2,231.80 |
| Rest of Illinois | Unavailable | $2,072.98 |
| Suburban Chicago, IL | Unavailable | $2,175.91 |
How the 35537 rate is calculated
Each of 35537’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 35537
RVUs × geographic indexes × conversion factor
Work40.83
40.83 RVUs× 1.000 GPCI
Practice expense5.35
5.35 RVUs× 1.000 GPCI
Malpractice10.46
10.46 RVUs× 1.000 GPCI
Adjusted RVUs
56.6400
Conversion factor
$33.4009
Medicare rate
$1,891.83
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 35537
35537 has a 90-day global period: related visits in that window are included in the surgery payment.
CMS payment indicators · 35537
Aortoiliac bypass, vein conduit, iliac outflow
| Rule | CMS value | What it means |
|---|---|---|
| Global period | 090 | Major surgery: the day before, the day of, and 90 days after are included. |
| Multiple procedures | 2 | Standard reduction: highest-valued procedure at 100%, others at 50%. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 2 | Paid. |
| Co-surgeons (62) | 1 | Permitted with supporting documentation. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 0 | Physician service: no professional/technical split. |
| Split (54/55/56) | 0.09/0.84/0.07 | Share of the payment for pre-op, the procedure itself, and post-op care. |
Global surgery period · 35537
Aortoiliac bypass, vein conduit, iliac outflow
90-day global period ends
Dec 30, 2026
Covers Sep 30, 2026 through Dec 30, 2026 (92 days, including the day before surgery).
Visit on Oct 31, 2026
Day 30 of the 90-day post-op period: related follow-up care is included in the surgical payment.
Pre-op dayGlobal period
What modifiers do to the payment
Modifier 51 · payment effect
With and without the modifier
35537 without 51 · national facility
$1,891.83
Aortoiliac bypass, vein conduit, iliac outflow
35537-51 · Second procedure: 50%
$945.92
When this isn’t the highest-valued procedure in the session, Medicare pays 50% of its fee schedule amount (the highest is paid at 100%).
35537 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 35538Aortic bypassAorta to both iliac arteries
- 35537 is for aortic bypass to an iliac artery; 35538 is the aortobi-iliac configuration, with outflow to both iliac arteries.
- 35539Aortic bypassSingle femoral target, vein conduit
- Choose 35539 when the aortic bypass ends at a femoral artery rather than an iliac artery.
- 35540Aortic bypassAutogenous vein conduit
- Choose 35540 for aortobifemoral bypass, with outflow to both femoral arteries; 35537 has iliac outflow.
35537 billing questions
How does this differ from 35538?
Use 35537 for a bypass from the aorta to an iliac artery. Code 35538 describes an aortic bypass to both iliac arteries.
When is 35539 or 35540 a better fit?
Those codes describe aortic bypasses with femoral rather than iliac outflow: 35539 for aortofemoral and 35540 for aortobifemoral reconstruction.
What operative details support 35537?
Document the aortic origin, the iliac outflow, use of a vein conduit, and the bypass performed. The documented endpoints distinguish this service from aortobi-iliac and aortofemoral bypasses.
Can modifier 50 be reported?
No. CMS identifies bilateral adjustment as inappropriate for this code; the descriptor or anatomy does not support modifier 50.
How does the global period affect postoperative visits?
The 90-day major-surgery global includes the day-before preoperative visit and 90 days of related postoperative care.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
Fee sheets
Put 35537 and the rest of your codes on one sheet
Your codes at your locality, with payer contracts beside Medicare.
Build my fee sheet