2026 ICD-10-CM Diagnosis Code I35.9Nonrheumatic aortic valve disorder, unspecified

ICD-10-CM Codes›I00–I99›I30-I5A›I35

ICD-10-CM I35.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I35.9 is a billable ICD-10-CM diagnosis code for nonrheumatic aortic valve disorder, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. Coders also document this condition as abnormality of aortic valve. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nonrheumatic and unspecified valve disorders.

This medical diagnosis code is frequently used in Cardiology medical specialties to designate conditions such nonrheumatic valve disorders - aortic valve disorders.

Code Identity

ICD-10-CM Code
I35.9
Billable Status
Yes — Valid for Submission
Code Describes
Nonrheumatic aortic valve disorder, unspecified
Short Description
Nonrheumatic aortic valve disorder, unspecified
Same as the full description in the CMS dataset.
Parent Code
I35
Nonrheumatic aortic valve disorders

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI30-I5AOther forms of heart disease
CategoryI35Nonrheumatic aortic valve disorders
This CodeI35.9Nonrheumatic aortic valve disorder, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormality of aortic valve
  • Aortic valve disease during pregnancy
  • Aortic valve disorder
  • Aortic valve disorder in mother complicating childbirth
  • Heart disease in mother complicating childbirth
  • Heart disease in mother complicating pregnancy, childbirth AND/OR puerperium

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disease, diseased
      • aortic (heart) (valve)
    • Disease, diseased
      • heart (organic)
        • aortic (valve)
    • Lesion(s) (nontraumatic)
      • aortic (valve)

Clinical ClassificationClinical

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

CCSR CIR003
Nonrheumatic and unspecified valve disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Heart Valve Diseases

Heart valve disease happens when one or more of your heart valves don't work well.

The full article covers:

  • What are heart valve diseases?
  • What are the types of heart valve diseases?
  • What causes heart valve diseases?
  • Who is more likely to develop heart valve diseases?
  • What are the symptoms of heart valve diseases?
  • What other problems can heart valve diseases cause?
  • How is heart valve disease diagnosed?
  • What are the treatments for heart valve diseases?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I35.9 to ICD-9-CMHistory

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

ICD-9-CM
424.1 Aortic valve disorder
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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I35.9Overview

Is I35.9 (Nonrheumatic aortic valve disorders) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report nonrheumatic aortic valve disorder, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I35.9 group to?

When nonrheumatic aortic valve disorder, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I35.9?

Under the General Equivalence Mappings, nonrheumatic aortic valve disorder, unspecified converts to ICD-9-CM 424.1 (aortic valve disorder). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.