Coronary Artery Disease: Documentation and Coding

By Leslie Smith

When most people think of coronary artery disease, also known as CAD, they may picture an older adult. However, from a medical coding perspective, age is not the determining factor. What matters most is the provider’s diagnosis, the supporting documentation, and the correct code selection based on the details documented in the medical record.

As medical coders, we are responsible for understanding how CAD is documented, how it should be coded, and what information must be present to support accurate coding. This is a condition I am familiar with personally, as one of my relatives has been diagnosed with coronary artery disease, and my father also experienced failing health that began with heart disease.

Receiving any type of heart disease diagnosis can be life-changing. While lifestyle changes such as a healthy diet, exercise, and regular follow-up appointments with qualified healthcare professionals may help manage certain conditions, this blog will focus specifically on the documentation and coding of CAD.

What Is Coronary Artery Disease?

According to Mrs. Jay, Director of AMCI Medical Coding Institute, coronary artery disease begins with the circulatory system and the flow of blood. CAD is also known as chronic ischemic heart disease and is reported within the ICD-10-CM code range for ischemic heart diseases, including I20 and I23–I25.

Coronary artery disease occurs when plaque builds up in the coronary arteries, causing narrowing or blockage. This buildup can reduce blood flow to the heart. When the heart does not receive enough oxygen-rich blood, the patient may experience complications such as chest pain, angina, hypertension, or other cardiovascular issues.

ICD-10-CM Codes Related to CAD

According to the article “Documenting and Coding Coronary Artery Disease (CAD)” by Natalie Tornese, the following are examples of ICD-10-CM codes related to CAD:

I25 – Chronic ischemic heart disease
I25.1 – Atherosclerotic heart disease of native coronary artery
I25.10 – Atherosclerotic heart disease of native coronary artery without angina pectoris
I25.11 – Atherosclerotic heart disease of native coronary artery with angina pectoris
I25.110 – Atherosclerotic heart disease of native coronary artery with unstable angina pectoris
I25.111 – Atherosclerotic heart disease of native coronary artery with unstable angina pectoris, with documented spasm
I25.118 – Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris
I25.119 – Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris

As coders, we must code to the highest level of accuracy and specificity supported by the documentation. It is also important to remember that coders can only code what the provider documents. As Mrs. Jay often states, “If it isn’t documented, it didn’t happen.”

CAD and Angina: Why Documentation Matters

Accurate documentation is essential when coding coronary artery disease, especially when angina is also documented.

According to ICD-10-CM coding guidance, a causal relationship is presumed between coronary artery disease and angina pectoris unless the provider clearly documents that the angina is unrelated. Therefore, when the provider documents both CAD and angina, coders should assign the appropriate combination code unless the documentation states otherwise.

Key documentation details to look for include:

• The type of artery involved
• Whether the condition involves a native coronary artery, bypass graft, or transplanted heart artery
• Whether angina is present
• The type of angina documented
• Whether there is documentation of spasm, unstable angina, or another specified form of angina

These details are important because they affect code selection and help ensure proper billing, compliance, and data accuracy.

Coding Specificity for CAD

The ICD-10-CM and ICD-10-PCS Coding Handbook 2025 explains that subcategory I25.1, atherosclerotic heart disease of native coronary artery, includes conditions such as:

• Atherosclerotic cardiovascular disease
• Coronary artery atheroma
• Coronary artery disease
• Coronary artery sclerosis

The fifth character identifies whether angina pectoris is present or absent. When angina is present, additional characters may identify the type, such as unstable angina, angina with documented spasm, other forms of angina, or unspecified angina.

This is why specificity and provider documentation are so important. Not every patient with CAD has angina pectoris, so coders must carefully review the record and select the code that accurately reflects the patient’s documented condition.

A Personal Perspective

One patient diagnosed with CAD shared that they did not experience the typical symptoms many people associate with heart disease. They had no chest tightness, no angina, and no obvious warning signs. It was not until further testing, including imaging and a heart catheterization, that the diagnosis was discovered.

This serves as an important reminder that heart disease does not always present in the same way for every patient. Some individuals may have symptoms, while others may have none at all.

Because heart disease has affected my own family, this topic is personal to me. If heart disease runs in your family, it is important to stay proactive about your health, attend regular medical appointments, and follow your provider’s recommendations.

Final Thoughts for Medical Coders

Coronary artery disease is an important condition for medical coders to understand. Accurate CAD coding requires careful review of the provider’s documentation, attention to specificity, and knowledge of ICD-10-CM coding guidelines.

When coding CAD, always ask:

• What type of artery is involved?
• Is angina documented?
• If angina is present, what type?
• Is the condition involving a native artery, bypass graft, or transplanted heart?
• Does the documentation support the code selected?

Over time, coders become more familiar with these codes and the documentation needed to support them. However, accuracy should always come first. When documentation is unclear, querying the provider may be necessary to ensure the correct code is assigned.

Coronary artery disease documentation and coding require attention to detail, clinical understanding, and a commitment to coding accuracy. As medical coders, our role is to tell the patient’s story through the codes, based on what the provider clearly documents.

About the Blogger

Leslie is pursuing her Medical Coding certification through Absolute Medical Coding Institute (AMCI). Her years of healthcare experience provide a strong foundation for this next step in her career. She embraces every opportunity to learn, develop new skills, and expand her expertise. Leslie takes pride in being part of the AMCI community and looks forward to the opportunities that medical coding will bring.