I26-I28
Medium Complexity

Pulmonary heart disease and diseases of pulmonary circulation

Primary Specialty: Cardiology
Last Updated: 2025-09-10

ICD-10 Codes (21)

17 billable
2 category headers
I27
Other pulmonary heart diseases
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I27.0
Billable
Primary pulmonary hypertension
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I27.1
Billable
Kyphoscoliotic heart disease
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I27.2
Other secondary pulmonary hypertension
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I27.20
Billable
Pulmonary hypertension, unspecified
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I27.21
Billable
Secondary pulmonary arterial hypertension
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I27.22
Billable
Pulmonary hypertension due to left heart disease
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I27.23
Billable
Pulmonary hypertension due to lung diseases and hypoxia
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I27.24
Billable
Chronic thromboembolic pulmonary hypertension
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I27.29
Billable
Other secondary pulmonary hypertension
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I27.8
Other specified pulmonary heart diseases
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I27.81
Billable
Cor pulmonale (chronic)
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I27.82
Billable
Chronic pulmonary embolism
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I27.83
Billable
Eisenmenger's syndrome
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I27.89
Billable
Other specified pulmonary heart diseases
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I27.9
Billable
Pulmonary heart disease, unspecified
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I28
Other diseases of pulmonary vessels
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I28.0
Billable
Arteriovenous fistula of pulmonary vessels
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I28.1
Billable
Aneurysm of pulmonary artery
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I28.8
Billable
Other diseases of pulmonary vessels
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I28.9
Billable
Disease of pulmonary vessels, unspecified
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Updates & Changes

FY 2026 Updates

Current Year

New Codes (1)

I16.9
Hypertensive crisis, unspecified, with target organ damage

Revised Codes (2)

I12.0
Hypertensive chronic kidney disease with stage 5 chronic kidney disease - updated staging
I15.9
Secondary hypertension, unspecified - enhanced documentation requirements

Deleted Codes

No codes deleted in this range for FY 2026

Historical Changes

  • FY 2025: Routine maintenance updates with minor terminology clarifications
  • FY 2024: Enhanced specificity requirements for certain code ranges
  • FY 2023: Updated documentation guidelines for improved clarity

Upcoming Changes

  • Proposed updates pending review by Coordination and Maintenance Committee
  • Under consideration: Enhanced digital health integration codes

Implementation Guidance

  • Review all FY 2026 updates for I26-I28 codes before implementation
  • Always verify the most current codes in the ICD-10-CM manual
  • Ensure clinical documentation supports the selected diagnosis codes
  • +3 more guidance items...

Range Overview

high priority

The I26-I28 category in ICD-10 covers codes related to pulmonary heart diseases and diseases of pulmonary circulation. These codes are used to document conditions such as pulmonary embolism, pulmonary hypertension, and other diseases affecting the pulmonary circulation. The codes in this category are essential for accurate medical documentation and billing, and they provide a standardized way to represent these conditions in health records.

Key Usage Points:

  • Always code to the highest level of specificity.
  • Use combination codes when a condition has both an underlying etiology and a manifestation.
  • Assign codes for all documented conditions that coexist at the time of the encounter.
  • Do not code conditions that were previously treated and no longer exist.
  • Follow the Alphabetic Index guidance for sequencing priority.

Coding Guidelines

When to Use:

  • When a patient is diagnosed with pulmonary embolism.
  • When a patient has chronic pulmonary heart disease.
  • When a patient presents with primary pulmonary hypertension.
  • When a patient has other diseases of pulmonary vessels.

When NOT to Use:

  • When the patient has a heart condition not related to the pulmonary system.
  • When the patient has a respiratory condition not affecting the pulmonary circulation.
  • When the patient's condition is related to the systemic circulation.
  • When the patient's condition is better represented by another code.

Code Exclusions

Always verify the exclusions in the Tabular List before assigning a code.

Documentation Requirements

Proper documentation for I26-I28 codes should include a clear diagnosis, the severity of the condition, any underlying conditions, and any complications. The documentation should be clear, concise, and specific.

Clinical Information:

  • Specific diagnosis
  • Severity of the condition
  • Underlying conditions
  • Complications

Supporting Evidence:

  • Lab results
  • Imaging results
  • Clinical notes
  • Patient history
Good Documentation Example:

Patient diagnosed with chronic thromboembolic pulmonary hypertension. CT scan confirms the diagnosis.

Poor Documentation Example:

Patient has a lung problem.

Common Documentation Errors:

  • Not coding to the highest level of specificity
  • Not documenting underlying conditions
  • Not documenting complications
  • Not providing supporting evidence

Range Statistics

3
Total Codes
17
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:9

Coding Complexity

Medium
Complexity Rating

The complexity of these codes is considered medium because they require a good understanding of the underlying conditions, the ability to identify the correct level of specificity, the ability to recognize complications, and the ability to follow sequencing rules.

Key Factors:
  • Understanding the underlying conditions
  • Identifying the correct level of specificity
  • Recognizing complications
  • Following sequencing rules

Specialty Focus

These codes are primarily used by specialists in cardiology and pulmonology. They are also relevant for general practitioners and emergency medicine physicians.

Primary Specialties:
Cardiology
50%
Pulmonology
30%
General Practice
20%
Clinical Scenarios:
  • A patient with a history of deep vein thrombosis presents with shortness of breath and is diagnosed with pulmonary embolism.
  • A patient with chronic obstructive pulmonary disease (COPD) develops cor pulmonale.
  • A patient presents with unexplained dyspnea and is diagnosed with primary pulmonary hypertension.
  • A patient with a history of pulmonary embolism presents with signs of chronic thromboembolic pulmonary hypertension.

Resources & References

The official ICD-10-CM guidelines, the American Heart Association, and the American Thoracic Society are excellent resources for information on these codes.

Official Guidelines:

  • ICD-10-CM Official Guidelines for Coding and Reporting
  • American Heart Association
  • American Thoracic Society

Clinical References:

    Educational Materials:

      Frequently Asked Questions

      What is the difference between I26 and I27 codes?

      I26 codes are used for pulmonary embolism, while I27 codes are used for other pulmonary heart diseases.