I66.29: Occlusion and stenosis of unspecified posterior cerebral artery
I66.29, occlusion and stenosis of unspecified posterior cerebral artery, is listed as a covered diagnosis in 6 Medicare billing and coding articles that apply to 22 HCPCS Level II codes, including C8925 (Transesophageal echocardiography (tee) with contrast, or…), C8926 (Transesophageal echocardiography (tee) with contrast, or…), C8927 (Transesophageal echocardiography (tee) with contrast, or…). The articles come from 4 Medicare contractors. A listed diagnosis supports medical necessity only; coverage still depends on the LCD's criteria and on documentation in the medical record.
HCPCS Level II codes with I66.29 as a covered diagnosis
| Code | Description | Medicare coverage | DMEPOS fee 2026 (state range) | Articles listing it |
|---|---|---|---|---|
| C8925 | Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, real time with image documentation (2d) (with or without m-mode recording); including probe placement, image acquisition, interpretation and report | Special coverage instructions apply | — | 2 |
| C8926 | Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; including probe placement, image acquisition, interpretation and report | Special coverage instructions apply | — | 2 |
| C8927 | Transesophageal echocardiography (tee) with contrast, or without contrast followed by with contrast, for monitoring purposes, including probe placement, real time 2-dimensional image acquisition and interpretation leading to ongoing (continuous) assessment of (dynamically changing) cardiac pumping function and to therapeutic measures on an immediate time basis | Special coverage instructions apply | — | 2 |
| J0461 | Injection, atropine sulfate, 0.01 mg | Special coverage instructions apply | — | 2 |
| J0153 | Injection, adenosine, 1 mg (not to be used to report any adenosine phosphate compounds) | Special coverage instructions apply | — | 2 |
| J1250 | Injection, dobutamine hydrochloride, per 250 mg | Special coverage instructions apply | — | 2 |
| J0280 | Injection, aminophyllin, up to 250 mg | Special coverage instructions apply | — | 2 |
| J1245 | Injection, dipyridamole, per 10 mg | Special coverage instructions apply | — | 2 |
| A9700 | Supply of injectable contrast material for use in echocardiography, per study | Special coverage instructions apply | — | 2 |
| G0453 | Continuous intraoperative neurophysiology monitoring, from outside the operating room (remote or nearby), per patient, (attention directed exclusively to one patient) each 15 minutes (list in addition to primary procedure) | Carrier judgment | — | 1 |
| J2785 | Injection, regadenoson, 0.1 mg | Carrier judgment | — | 1 |
| Q9957 | Injection, perflutren lipid microspheres, per ml | Carrier judgment | — | 1 |
| Q9956 | Injection, octafluoropropane microspheres, per ml | Carrier judgment | — | 1 |
| C8921 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; complete | Special coverage instructions apply | — | 1 |
| C8922 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, for congenital cardiac anomalies; follow-up or limited study | Special coverage instructions apply | — | 1 |
| C8923 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, complete, without spectral or color doppler echocardiography | Special coverage instructions apply | — | 1 |
| C8924 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, follow-up or limited study | Special coverage instructions apply | — | 1 |
| C8928 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, during rest and cardiovascular stress test using treadmill, bicycle exercise and/or pharmacologically induced stress, with interpretation and report | Special coverage instructions apply | — | 1 |
| C8929 | Transthoracic echocardiography with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, complete, with spectral doppler echocardiography, and with color flow doppler echocardiography | Special coverage instructions apply | — | 1 |
| C8930 | Transthoracic echocardiography, with contrast, or without contrast followed by with contrast, real-time with image documentation (2d), includes m-mode recording, when performed, during rest and cardiovascular stress test using treadmill, bicycle exercise and/or pharmacologically induced stress, with interpretation and report; including performance of continuous electrocardiographic monitoring, with physician supervision | Special coverage instructions apply | — | 1 |
| Q9955 | Injection, perflexane lipid microspheres, per ml | Carrier judgment | — | 1 |
| G0451 | Development testing, with interpretation and report, per standardized instrument form | Carrier judgment | — | 1 |
Medicare policy articles listing I66.29
- A57179: Billing and Coding: Transesophageal Echocardiogram (First Coast Service Options, Inc. (MAC - Part A, MAC - Part B); 3 Level II codes). LCD with the same title: L33756
- A52868: Billing and Coding: Transesophageal Echocardiography (TEE) (Wellpoint Federal (MAC - Part A, MAC - Part B); 3 Level II codes). LCD with the same title: L33579, L34337, L35016
- A56722: Billing and Coding: Intraoperative Neurophysiological Testing (Novitas Solutions, Inc. (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34623, L35003
- A56781: Billing and Coding: Transthoracic Echocardiography (TTE) (Wellpoint Federal (MAC - Part A, MAC - Part B); 17 Level II codes). LCD with the same title: L33577, L34338
- A56625: Billing and Coding: Echocardiography (Palmetto GBA (MAC - Part A, MAC - Part B); 6 Level II codes). LCD with the same title: L37379
- A57780: Billing and Coding: Psychological and Neuropsychological Tests (First Coast Service Options, Inc. (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34520
A diagnosis listed as covered in a billing and coding article supports medical necessity for the article's codes; it does not guarantee payment. Coverage depends on the LCD's criteria, the contractor's jurisdiction and documentation in the medical record.
Other I66 diagnoses (Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction)
- I66.21 — Occlusion and stenosis of right posterior cerebral artery
- I66.22 — Occlusion and stenosis of left posterior cerebral artery
- I66.23 — Occlusion and stenosis of bilateral posterior cerebral arteries
- I66.01 — Occlusion and stenosis of right middle cerebral artery
- I66.02 — Occlusion and stenosis of left middle cerebral artery
- I66.03 — Occlusion and stenosis of bilateral middle cerebral arteries
- I66.09 — Occlusion and stenosis of unspecified middle cerebral artery
- I66.11 — Occlusion and stenosis of right anterior cerebral artery
- I66.12 — Occlusion and stenosis of left anterior cerebral artery
- I66.13 — Occlusion and stenosis of bilateral anterior cerebral arteries
- I66.19 — Occlusion and stenosis of unspecified anterior cerebral artery
- I66.3 — Occlusion and stenosis of cerebellar arteries
- I66.8 — Occlusion and stenosis of other cerebral arteries
- I66.9 — Occlusion and stenosis of unspecified cerebral artery
Frequently asked questions
Does Medicare cover I66.29 (Occlusion and stenosis of unspecified posterior cerebral…)?
Medicare covers items and services, not diagnoses. 6 Medicare billing and coding articles list I66.29 as a covered diagnosis for 22 HCPCS Level II codes: the diagnosis can support medical necessity for those codes, but payment still depends on the LCD's coverage criteria and the medical record.
Which HCPCS codes can be billed with ICD-10 I66.29?
The Level II codes from the policies most specific to this diagnosis are C8925 (Transesophageal echocardiography (tee) with contrast, or…, 2 articles); C8926 (Transesophageal echocardiography (tee) with contrast, or…, 2 articles); C8927 (Transesophageal echocardiography (tee) with contrast, or…, 2 articles); J0461 (Injection, atropine sulfate, 0.01 mg, 2 articles); J0153 (Injection, adenosine, 1 mg (not to be used to report any…, 2 articles). Code choice depends on the item supplied; check each code's descriptor.
Which Medicare policy articles list I66.29?
A57179 (Billing and Coding: Transesophageal Echocardiogram); A52868 (Billing and Coding: Transesophageal Echocardiography (TEE)); A56722 (Billing and Coding: Intraoperative Neurophysiological Testing), and 3 more articles.
What is ICD-10-CM code I66.29?
I66.29 is the ICD-10-CM code for occlusion and stenosis of unspecified posterior cerebral artery, in category I66 (Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction), chapter 9: Diseases of the circulatory system.
Next steps
- Run a reimbursement report for a device billed under C8925
- Watch C8925 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for C8925
Sources: CMS Medicare Coverage Database billing and coding articles (covered ICD-10 code lists and HCPCS links); ICD-10-CM FY2026; CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule 2026 (non-rural state fees). Not billing or legal advice.
Chapter 9: Diseases of the circulatory system · All diagnoses · HCPCS lookup