2027 ICD-10-CM Diagnosis Code I97.821Postprocedural cerebrovascular infarction following other surgery

ICD-10-CM Codes›I00–I99›I95-I99›I97

ICD-10-CM I97.821
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I97.821 is a billable ICD-10-CM diagnosis code for postprocedural cerebrovascular infarction following other surgery. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 60 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cerebral infarction and Postprocedural or postoperative circulatory system complication.

I97.821 no longer risk-adjusts for Medicare Advantage: it mapped to HCC 100 under the retired CMS-HCC V24 model through payment year 2025 but maps to no category in the live V28 model. It still risk-adjusts in the PACE (CMS-HCC V22) category 100, ESRD (V21) category 100, and ESRD (V24) category 100 for payment year 2027.

Code Identity

ICD-10-CM Code
I97.821
Billable Status
Yes — Valid for Submission
Code Describes
Postprocedural cerebrovascular infarction following other surgery
Short Description
Postprocedural cerebvasc infarction following other surgery
Parent Code
I97.82
Postprocedural cerebrovascular infarction

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI95-I99Other and unspecified disorders of the circulatory system
CategoryI97Intraoperative and postprocedural complications and disorders of circulatory system, not elsewhere classified
This CodeI97.821Postprocedural cerebrovascular infarction following other surgery

Medicare Risk Adjustment (HCC)Billing

I97.821 no longer risk-adjusts for Medicare Advantage: it maps to no payment category in the live CMS-HCC V28 model, although it still risk-adjusts in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
Dropped in V28 see all codes that no longer risk-adjust
Prior Model (CMS-HCC V24)
HCC 100
V24 retired last contributed to a Medicare Advantage risk score in payment year 2025
Other CMS Models
PACE (CMS-HCC V22): HCC 100 · ESRD (V21): HCC 100 · ESRD (V24): HCC 100
ESRD V21 weights: 0.078 dialysis, 0.105–0.252 functioning graft · ESRD V24 weights: 0.062 dialysis, 0.082–0.355 functioning graft
Part D (RxHCC)
Not mapped
I97.821 does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I97.821: its own notes plus those printed at I97.8, I97, and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From I97 Intraoperative and postprocedural complications and disorders of circulatory system, not elsewhere classified applies to 39 codes
From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From I97.8 Other intraoperative and postprocedural complications and disorders of the circulatory system, not elsewhere classified applies to 6 codes
  • code, if applicable, to further specify disorder

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name I97.821, its category, or a range that includes it.

Excludes2 1

These codes carry an Excludes2 note naming I97.821: its condition is not part of those codes, and both may be reported when the patient has both.

  • G97 Intraoperative and postprocedural complications and disorders of nervous system, not elsewhere classified
    intraoperative and postprocedural cerebrovascular infarction (I97.81-, I97.82-) names I97.82-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR020
Cerebral infarction
Default principal diagnosis: inpatient No · outpatient No
CCSR CIR038
Postprocedural or postoperative circulatory system complication
Default principal diagnosis: inpatient Yes · outpatient Yes

Convert I97.821 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
997.02 Iatrogen CV infarc/hmrhg
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I97.821Overview

What is the ICD-10 code for postprocedural cerebrovascular infarction following other surgery?

The ICD-10-CM code for postprocedural cerebrovascular infarction following other surgery is I97.821 (sometimes written as I97821). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I97.821 (Postprocedural cerebrovascular infarction) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report postprocedural cerebrovascular infarction following other surgery on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I97.821 group to?

When postprocedural cerebrovascular infarction following other surgery is the principal diagnosis on an inpatient stay, it groups to MS-DRG 91, 92, 93, with relative weights from 0.7783 to 1.7050 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I97.821 a CC or MCC?

CMS lists I97.821 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 60 closely related codes in its exclusion list.

Does I97.821 need an additional code?

When the condition applies, yes. The Use Additional Code note at I97.8, which applies to I97.821, reads: code, if applicable, to further specify disorder. The additional code is reported after I97.821.

Does I97.821 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage. I97.821 mapped to HCC 100 in the retired CMS-HCC V24 model, which last determined payment in 2025, but it maps to no category in the live V28 model; see all codes that no longer risk-adjust. It still risk-adjusts in the PACE (CMS-HCC V22) category 100 (Ischemic or Unspecified Stroke), ESRD (V21) category 100 (Ischemic or Unspecified Stroke), and ESRD (V24) category 100 (Ischemic or Unspecified Stroke).