ICD-10 Code for Cardiac Surgery: Codes, Procedures & Coding Guide

There is no single ICD-10 code for cardiac surgery. The correct code depends on what is being reported: the cardiac condition being treated, an encounter for postoperative aftercare, a postsurgical status, or the actual inpatient procedure.

That distinction matters because ICD-10-CM and ICD-10-PCS serve different purposes. This guide explains which coding category applies to common cardiac surgery situations and what documentation should support the selection.

Is There an ICD-10 Code for Cardiac Surgery?

The phrase “cardiac surgery” describes a procedure, not a specific diagnosis.

A patient may undergo heart surgery because of coronary artery disease, a valve disorder, an aortic condition, or another documented cardiovascular problem. The diagnosis code should reflect the condition documented by the provider. The actual inpatient operation, when applicable, is reported separately through ICD-10-PCS.

For postoperative care, a different coding question arises. Z48.812, Encounters for surgical aftercare following surgery on the circulatory system, may apply when the patient is receiving aftercare following circulatory-system surgery. CMS’s FY2026 Official Guidelines also give Z95.1, Presence of aortocoronary bypass graft, as an example of a status code that may be reported with Z48.812 to identify the surgery involved.

So, the answer to “What is the ICD-10 code for cardiac surgery?” depends on the encounter.

ICD-10-CM vs. ICD-10-PCS for Cardiac Surgery

Understanding which coding system applies is one of the first steps in cardiac surgery coding.

ICD-10-CM

ICD-10-CM is used to report diagnoses and other circumstances surrounding the patient’s encounter. For cardiac surgery-related encounters, this may include:

• The underlying cardiovascular condition
• Surgical aftercare
• Postsurgical or device status
• A documented complication
• Other conditions that meet the reporting requirements

For example, Z95.1 describes the presence of an aortocoronary bypass graft. It does not describe a CABG operation performed during the current encounter. CMS lists Z95.1 under the category for cardiac and vascular implants and grafts.

ICD-10-PCS

ICD-10-PCS is used to report procedures performed during an inpatient hospital stay. Cardiac procedures are not represented by one generic PCS code. The exact code depends on the details of the operation, including the body part, root operation, approach, device, and other required characters.

CMS’s FY2026 materials include separate procedure groupings for coronary bypass, cardiac valve and major cardiothoracic procedures, cardiac defibrillator implantation, pacemaker procedures, aortic and heart-assist procedures, and other cardiovascular procedures.

That is why a procedure name such as “heart surgery” is not enough information to select an ICD-10-PCS code.

Common ICD-10-CM Codes Related to Cardiac Surgery

Several Z codes may appear in records involving previous cardiac procedures or postoperative care. They should not be treated as interchangeable.

CMS materials identify these codes within the Z95 category for cardiac and vascular implants and grafts.

Z48.812: Cardiac surgery aftercare

Z48.812 is one of the most relevant codes when the search intent is postoperative cardiac surgery care.

The description is:

Encounter for surgical aftercare following surgery on the circulatory system

This code addresses the aftercare encounter, not the original cardiac operation.

CMS’s FY2026 guidelines explain that aftercare codes are used when the patient is receiving continued care during the healing or recovery period. The guidelines also specifically state that Z95.1 may be used with Z48.812 to indicate the nature of the surgery for which aftercare is being provided.

For example, if documentation supports an encounter for surgical aftercare following CABG, the coding picture is different from simply reporting that the patient has a history of CABG.

Z95.1: Presence of aortocoronary bypass graft

Z95.1 identifies the presence of an aortocoronary bypass graft.

It is a status code, not the code for the CABG procedure itself. CMS specifically uses Z95.1 as an example of a status code that can accompany Z48.812 for circulatory-system surgical aftercare.

That distinction is easy to miss when the medical record repeatedly mentions the patient’s previous bypass surgery.

Z95.2 and other valve-related status codes

A patient who has undergone valve surgery may have a documented prosthetic, xenogenic, or other heart-valve replacement. The applicable status code depends on what is documented.

For example:

• Z95.2 — Presence of prosthetic heart valve
• Z95.3 — Presence of xenogenic heart valve
• Z95.4 — Presence of other heart-valve replacement

The code should match the documented valve status rather than being selected simply because the patient had “heart valve surgery.”

How Cardiac Surgery Is Reported in ICD-10-PCS

When an inpatient hospital procedure is being coded, the operative details determine the ICD-10-PCS code. Cardiac surgery can involve very different procedures, and ICD-10-PCS provides distinct codes for them.

Coronary artery bypass surgery

CABG procedures fall into the ICD-10-PCS cardiovascular procedure structure. CMS’s FY2026 materials list coronary bypass as a distinct surgical category and provide individual PCS codes based on the artery, graft material, approach, and other procedure details.

For example, CMS lists PCS codes beginning with 021 for bypass procedures involving coronary arteries. The complete code cannot be selected from the term “CABG” alone because the operative documentation supplies additional information needed to build the code.

Heart valve surgery

Valve procedures are another major cardiac surgery category.

The operative report may need to establish details such as:

• Which valve was treated
• What procedure was performed
• Whether a device was used
• The approach
• Other details required by the PCS code structure

CMS’s FY2026 DRG materials separately identify cardiac valve and other major cardiothoracic procedures and concomitant aortic and mitral valve procedures.

Pacemaker and defibrillator procedures

Cardiac device procedures are also represented in ICD-10-PCS.

CMS’s FY2026 materials identify separate categories for permanent cardiac pacemaker implantation, pacemaker replacement or revision, AICD generator procedures, AICD lead procedures, and cardiac defibrillator implantation.

These should not be reduced to a generic “cardiac surgery” code.

Aortic and other cardiothoracic procedures

Cardiac surgery may involve the aorta, heart-assist systems, or other structures within the cardiovascular system.

CMS’s FY2026 materials include categories for complex aortic arch procedures, aortic and heart-assist procedures, other cardiothoracic procedures, and other major cardiovascular procedures.

The operative documentation needs to provide enough detail for the coder to identify the correct PCS code.

What Documentation Supports Cardiac Surgery Coding?

The operation name alone may not answer the coding question.

For an inpatient procedure, the operative report should provide the details needed to identify what was actually performed. Depending on the surgery, that may include the body part treated, procedure performed, approach, graft or device used, and other required PCS elements.

For ICD-10-CM diagnosis and status coding, the record should establish what condition or status is being reported.

Documentation should distinguish between:

• A current cardiac condition
• A previous cardiac operation
• An encounter for postoperative aftercare
• A postsurgical or device status
• A current surgical complication
• A procedure performed during the current admission

This distinction becomes particularly important when the same surgical history appears in multiple encounters.

A patient who had CABG several months ago does not automatically have a current CABG procedure to report. Likewise, a patient returning for postoperative care should not have the aftercare code treated as though it were the code for the original operation.

Common Cardiac Surgery Coding Mistakes

Using one code for every cardiac surgery encounter

“Cardiac surgery” is too broad to determine a single ICD-10 code. The coder must first establish what is being reported.

Confusing aftercare with the original procedure

Z48.812 describes an aftercare encounter. It does not replace the ICD-10-PCS code for an inpatient cardiac operation.

Treating a status code as a procedure code

Z95.1 identifies the presence of an aortocoronary bypass graft. It does not report that a CABG procedure was performed during the current encounter.

Choosing a PCS code from the procedure name alone

“CABG,” “valve replacement,” or “heart surgery” may not provide all the details needed to construct an ICD-10-PCS code.

Assuming a diagnosis from the procedure

The fact that a patient underwent cardiac surgery does not, by itself, establish every diagnosis that might clinically be associated with that operation. The diagnosis should come from the provider’s documentation.

How Providers Can Reduce Cardiac Surgery Coding Problems

The most useful documentation is specific enough to tell the coding team what actually happened. For cardiac procedures, providers should clearly document the diagnosis being treated and the procedure performed. Operative documentation should contain the procedural details required for accurate PCS assignment.

For postoperative visits, clearly stating the reason for the encounter also matters. A note that simply says “follow-up after heart surgery” may leave important coding questions unanswered.

A clearer note identifies whether the patient is receiving routine surgical aftercare, being evaluated for a complication, or being seen for an unrelated or ongoing cardiac condition.

Frequently Asked Questions

What is the ICD-10 code for cardiac surgery?

There is no single ICD-10-CM code for cardiac surgery. The appropriate code depends on whether you are reporting the underlying diagnosis, postoperative aftercare, a postsurgical status, or an inpatient procedure.

What is Z48.812 used for?

Z48.812 is used for an encounter for surgical aftercare following surgery on the circulatory system when the encounter meets the applicable aftercare guidelines. CMS specifically gives it as an aftercare code that may be paired with a relevant status code such as Z95.1.

What is the ICD-10 code for CABG status?

Z95.1 is the presence of aortocoronary bypass graft. It describes the patient’s bypass graft status rather than the CABG procedure itself.

Is cardiac surgery coded with ICD-10-CM or ICD-10-PCS?

It depends on what is being reported. ICD-10-CM is used for diagnoses and other circumstances surrounding the encounter, while ICD-10-PCS is used for applicable inpatient hospital procedures. Cardiac operations have specific PCS codes based on the details of the procedure.

What is the ICD-10 code for a prosthetic heart valve?

Z95.2 describes the presence of a prosthetic heart valve. Other Z95.- codes apply to different types of heart-valve replacements or cardiac implants, so the documented valve status matters.

Does a history of cardiac surgery mean the surgery should be coded again?

No. A previous cardiac operation does not mean the same procedure should be reported on every subsequent encounter. The current encounter, documented diagnosis, aftercare status, and applicable coding guidelines determine what should be reported.