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9.1 Coronary Artery Bypass Grafting (CABG) & Percutaneous Coronary Interventions

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1 Chapter 1: ICD-10-CM Diagnosis Coding Fundamentals & UHDDS Guidelines

1.1 ICD-10-CM Structure, Formats, and Core Conventions 1.2 UHDDS Principal Diagnosis Selection Rules 1.3 Secondary Diagnoses Reporting & Present on Admission (POA) Indicators

2 Chapter 2: Circulatory, Cardiac & Vascular Inpatient Coding

2.1 Hypertension, Hypertensive Heart & Chronic Kidney Disease, and CAD 2.2 Acute Myocardial Infarction (AMI) Types & Sequencing 2.3 Heart Failure Types, Acuity & Cardiomyopathy 2.4 Cerebrovascular Disease, Acute Stroke, and Late Effects

3 Chapter 3: Respiratory, Sepsis & Infectious Conditions Coding

3.1 Sepsis, Severe Sepsis, and Septic Shock Guidelines 3.2 Pneumonias, Aspiration Pneumonia, and Influenza 3.3 COPD, Asthma, and Acute Respiratory Failure

4 Chapter 4: Renal, Endocrine, Gastrointestinal & Nutritional Disorders

4.1 Acute Kidney Injury (AKI) & Chronic Kidney Disease (CKD) 4.2 Diabetes Mellitus Types, Manifestations & Complications 4.3 Protein-Calorie Malnutrition & Endocrine Emergencies 4.4 Gastrointestinal Bleeding, Ulcers, and Acute Abdominal Pathologies

5 Chapter 5: Neoplasms, Obstetrics, Perinatal, Injury & Trauma Coding

5.1 Neoplasm Table, Primary, Secondary & Encounters for Therapy 5.2 Obstetrics, Normal/Complicated Deliveries & Puerperium 5.3 Perinatal Conditions & Congenital Malformations 5.4 Traumatic Injuries, Fractures & 7th Character Extensions

6 Chapter 6: ICD-10-PCS Architecture, Conventions & Approaches

6.1 ICD-10-PCS 7-Character System Architecture & Conventions 6.2 ICD-10-PCS The Seven Surgical Approaches 6.3 General PCS Guidelines & Multiple Procedure Rules

7 Chapter 7: ICD-10-PCS Root Operations: Cutting Out, Taking Out & Altering Body Parts

7.1 Excision vs Resection vs Destruction 7.2 Extraction, Drainage, and Extirpation 7.3 Detachment & Amputation Coding 7.4 Release vs Division

8 Chapter 8: ICD-10-PCS Root Operations: Putting In, Putting Back & Moving Body Parts

8.1 Replacement vs Supplement vs Insertion 8.2 Reposition, Transfer, and Reattachment 8.3 Bypass, Dilation, Occlusion, and Restriction

9 Chapter 9: High-Volume Inpatient Surgical & Medical Procedures in ICD-10-PCS

9.1 Coronary Artery Bypass Grafting (CABG) & Percutaneous Coronary Interventions 9.2 Total Joint Arthroplasties & Spinal Fusion 9.3 Mechanical Ventilation & Extracorporeal Therapies

10 Chapter 10: Outpatient CPT & HCPCS Level II Coding & Modifiers

10.1 CPT Evaluation and Management (E/M) Guidelines 10.2 CPT Surgical, Radiology, Pathology & HCPCS Level II Coding 10.3 CPT Modifiers in Hospital Outpatient & Professional Coding

11 Chapter 11: Inpatient Record Review, Clinical Validation & Documentation Integrity

11.1 Inpatient Health Record Analysis & UHDDS Documentation Hierarchy 11.2 Clinical Validation of Diagnoses vs Coding Compliance 11.3 Identifying Reportable Secondary Conditions & Complications

12 Chapter 12: Compliant Provider Queries & AHIMA/ACDIS Standards

12.1 AHIMA/ACDIS Compliant Query Standards & Ethical Principles 12.2 Compliant Query Formats: Open-Ended, Multiple-Choice & Yes/No 12.3 High-Impact Clinical Query Scenarios & Provider Workflow

13 Chapter 13: Inpatient Prospective Payment System (IPPS) & MS-DRG Mechanics

13.1 IPPS Reimbursement Structure & MS-DRG Grouping Logic 13.2 Complications and Comorbidities (CC) & Major CC (MCC) Impact 13.3 All-Patient Refined DRG (APR-DRG) System 13.4 Inpatient Transfer Policies, Cost Outliers & Short-Stay Rules

14 Chapter 14: Outpatient Reimbursement, Coding Edits & Fraud/Abuse Compliance

14.1 Hospital Outpatient Prospective Payment System (OPPS) & APCs 14.2 National Correct Coding Initiative (NCCI) Edits & MUEs 14.3 Hospital-Acquired Conditions (HAC) Reduction & Quality Programs 14.4 Healthcare Fraud, Abuse Laws, Audits & AHIMA Ethical Standards

15 Chapter 15: Health Information Technology, CAC, Encoders & Data Security

15.1 Electronic Health Records (EHR) & Computer-Assisted Coding (CAC) 15.2 Logic-Based Encoders, Groupers & Health Data Systems 15.3 HIPAA Privacy/Security, Cybersecurity & Internal Coding Audits

9.1 Coronary Artery Bypass Grafting (CABG) & Percutaneous Coronary Interventions

Key Takeaways Explain This Topic AI

In ICD-10-PCS Table 021, the body part character represents the NUMBER of coronary artery sites bypassed (1, 2, 3, or 4+ sites), rather than individual named arterial branches.

Multi-vessel CABG procedures require separate codes whenever grafts differ by device (conduit tissue type) or qualifier (originating source vessel), such as combining a pedicled internal mammary artery graft with an aorta-to-coronary saphenous vein graft.

Procurement of autologous venous or radial artery grafts is coded separately as an Excision procedure under Guideline B3.9, whereas pedicled arterial grafts (e.g., LIMA kept intact at its subclavian origin) do not receive a harvest code.

Percutaneous Coronary Interventions in Table 027 utilize root operation Dilation, with the 6th character distinguishing drug-eluting vs. non-drug-eluting stents and device counts, while the 4th character reflects the number of distinct coronary vessel sites dilated.

Last updated: August 2026

Coronary Artery Bypass Grafting (CABG) & Percutaneous Coronary Interventions

AHIMA CCS Exam Focus: Coronary revascularization procedures represent some of the highest-volume, highest-weighted inpatient surgical cases on the CCS examination. Candidates must demonstrate flawless mastery of ICD-10-PCS coding rules for Coronary Artery Bypass Grafting (CABG / Table 021) and Percutaneous Coronary Interventions (PCI / Table 027). Key testing domains include determining the exact number of coronary artery sites treated, properly combining conduit devices and originating vessel qualifiers, identifying when autologous graft harvesting must be coded separately, and differentiating drug-eluting from non-drug-eluting stents in multi-vessel dilation.

1. Coronary Anatomy and Clinical Revascularization

The coronary circulation consists of arterial networks supplying oxygenated blood to the myocardium. The two primary main branches arising from the aortic sinuses are the Left Main Coronary Artery (LMCA) and the Right Coronary Artery (RCA) .

Left Coronary System: The LMCA bifurcates into the Left Anterior Descending (LAD) artery (supplying the anterior wall and interventricular septum, giving off diagonal branches) and the Left Circumflex (LCx) artery (supplying the lateral and posterior left ventricle, giving off obtuse marginal branches). In some individuals, a third branch arises called the Ramus Intermedius .

Right Coronary System: The RCA traverses the right atrioventricular groove, giving off acute marginal branches and commonly terminating as the Posterior Descending Artery (PDA) and posterolateral branches.

When atherosclerotic plaque causes critical stenosis (typically ≥ 70 % \ge 70\% ≥ 70% , or ≥ 50 % \ge 50\% ≥ 50% for the LMCA), myocardial revascularization is indicated. Revascularization is achieved surgically via Coronary Artery Bypass Grafting (CABG) or percutaneously via Percutaneous Coronary Intervention (PCI) . [Ascending Aorta]

  • / \
  • [LMCA] [RCA]
  • / \ \
  • [LAD] [LCx] [PDA]
  • / \
  • [Diagonals] [Obtuse Marginals]
  • 2. CABG Coding Architecture (Table 021)

In ICD-10-PCS, coronary artery bypass grafting is classified under Section 0 (Medical and Surgical) , Body System 2 (Heart and Great Vessels) , and Root Operation 1 (Bypass) . ICD-10-PCS CABG Table Structure (021):

  • [0] Section ➔ Medical and Surgical
  • [2] Body System ➔ Heart and Great Vessels
  • [1] Root Op ➔ Bypass (Altering route of passage of contents of tubular body part)
  • [4] Body Part ➔ Number of Coronary Artery Sites Treated (0, 1, 2, 3)
  • [5] Approach ➔ Open (0) or Percutaneous Endoscopic (4)
  • [6] Device ➔ Conduit Type (9, A, J, K, Z)
  • [7] Qualifier ➔ Vessel Bypassed From / Source (3, 8, 9, A, W, F)
  • Character 4: Body Part (Number of Coronary Artery Sites Treated)

Unlike other vascular bypass procedures where the body part represents a specific anatomical artery, the body part in coronary bypass coding represents the total number of distinct coronary artery distal anastomoses (sites treated) for a specific device and qualifier combination:

  • 0 = Coronary Artery, One Site
  • 1 = Coronary Artery, Two Sites
  • 2 = Coronary Artery, Three Sites
  • 3 = Coronary Artery, Four or More Sites

Core Rule: The body part value does not identify the name of the coronary artery (e.g., LAD vs. RCA). Instead, it reflects the count of distal anastomosis attachment points. If a surgeon grafts the LAD and a Diagonal branch using a single continuous saphenous vein conduit (a "sequential" or "jump" graft), two coronary artery sites have been treated.

Character 6: Device (Conduit Tissue Type)

The device character specifies the physical biological or synthetic material used as the vascular bridge:

9 = Autologous Venous Tissue (e.g., Greater Saphenous Vein, Lesser Saphenous Vein, Cephalic Vein)

A = Autologous Arterial Tissue (e.g., Left Internal Mammary Artery [LIMA], Right Internal Mammary Artery [RIMA], Radial Artery, Gastroepiploic Artery, Inferior Epigastric Artery)

  • J = Synthetic Substitute (e.g., PTFE, Dacron graft)
  • K = Nonautologous Tissue Substitute (e.g., Bovine pericardial conduit, cadaveric homograft)

Z = No Device (rarely used in CABG; applied when direct anastomosis connects two severed vessels without an intervening graft)

Character 7: Qualifier (Originating Vessel / Vessel Bypassed From)

The qualifier identifies the upstream source of arterial blood (the proximal anastomosis or vessel of origin):

  • W = Aorta (standard proximal connection for saphenous vein and free arterial grafts)
  • 8 = Internal Mammary, Right (used when the right internal mammary artery is mobilized as a pedicle graft)
  • 9 = Internal Mammary, Left (used when the left internal mammary artery is mobilized as a pedicle graft)

A = Thoracic Artery (used for other thoracic arterial sources, or free internal mammary grafts originating from other thoracic arteries)

3 = Coronary Artery (used when a bypass originates from a coronary artery, e.g., graft-to-graft or coronary-to-coronary bypass)

F = Abdominal Artery (e.g., Right Gastroepiploic Artery originating below the diaphragm)

  • Character Position Value Meaning / Clinical Translation
  • 1: Section 0 Medical and Surgical
  • 2: Body System 2 Heart and Great Vessels
  • 3: Root Operation 1 Bypass

4: Body Part 0 , 1 , 2 , 3 Number of coronary artery sites treated ( 0 =1 site, 1 =2 sites, 2 =3 sites, 3 =4+ sites)

  • 5: Approach 0 Open (Sternotomy / Thoracotomy)
  • 4 Percutaneous Endoscopic (Robotic / Minimally Invasive Direct CABG [MIDCAB])
  • 6: Device 9 Autologous Venous Tissue (Saphenous vein)
  • A Autologous Arterial Tissue (IMA, Radial artery)
  • J / K Synthetic Substitute / Nonautologous Tissue Substitute
  • 7: Qualifier W Aorta (Proximal anastomosis to ascending aorta)
  • 8 / 9 Internal Mammary, Right / Left (Pedicle graft source)
  • 3 / A / F Coronary Artery / Thoracic Artery / Abdominal Artery
  • 3. Multi-Vessel CABG Coding Rules & Guidelines
  • Coding Guidelines B3.6b and B3.6c (Coronary Artery Bypass)

Guideline B3.6b makes Character 4 the number of coronary arteries bypassed to and the qualifier the vessel bypassed from. Guideline B3.6c then requires a separate code for each combination using a different device and/or qualifier. Thus, different conduit materials or source vessels can require multiple bypass codes in one operative episode. Multi-Vessel CABG Coding Decision Flowchart:

Step 1: Identify all coronary distal target sites (e.g., LAD, Diag 1, OM 1, PDA = 4 sites).

Step 2: Group distal sites by Conduit Device (Venous vs. Arterial) AND Source Qualifier (Aorta vs. LIMA/RIMA).

Step 3: Assign one PCS code for each distinct [Device + Qualifier] group, setting Body Part to count of sites in that group.

Step 4: Determine if autograft harvest requires separate code(s) per Guideline B3.9.

Pedicled vs. Free Arterial Grafts

Pedicled Graft (In Situ): The internal mammary artery remains attached at its native source and its distal end is anastomosed to the coronary artery.

Device: Z (No Device), because the pedicled artery is represented by the source qualifier rather than as a detached graft device

  • Qualifier: 9 (Left Internal Mammary) or 8 (Right Internal Mammary)
  • Code Example (one artery from LIMA): 02100Z9

Free Graft: An artery (e.g., Radial Artery, or a detached segment of IMA) is completely excised from its native location and transplanted as a free conduit with a proximal anastomosis to the aorta.

  • Device: A (Autologous Arterial Tissue)
  • Qualifier: W (Aorta)
  • Code Example (1 site): 02100AW
  • Autologous Graft Harvesting (Guideline B3.9)

According to Guideline B3.9 ( Excision of autograft ):

"If an autograft is obtained from a different body part in order to complete the objective of the procedure, a separate procedure is coded for harvest of the autograft."

Graft Type Procurement Technique Harvest Coded? ICD-10-PCS Harvest Code

Greater Saphenous Vein (Right) Open incision of right lower extremity YES 06BP0ZZ ( Excision of Right Greater Saphenous Vein, Open )

Greater Saphenous Vein (Left) Endoscopic Vein Harvesting (EVH) YES 06BQ4ZZ ( Excision of Left Greater Saphenous Vein, Percutaneous Endoscopic )

Lesser Saphenous Vein (Right) Open incision YES 06BP0ZZ ( Excision of Right Saphenous Vein, Open ); the current table does not encode “lesser” in this body-part value

Radial Artery (Left) Open incision of left forearm YES 03BC0ZZ ( Excision of Left Radial Artery, Open )

Pedicled LIMA / RIMA Mobilization from chest wall (in situ) NO No separate harvest code (not excised/severed from body)

Comprehensive Case Study: Quadruple CABG

Operative Report Summary: A 66-year-old male with severe three-vessel CAD undergoes open CABG x 4 via median sternotomy. The left internal mammary artery is mobilized in a pedicled fashion and anastomosed to the left anterior descending (LAD) artery. An autologous greater saphenous vein graft is harvested endoscopically from the left leg. The saphenous vein is fashioned into a bifurcated/sequential graft from the ascending aorta to the first diagonal branch, the first obtuse marginal (OM1) branch, and the posterior descending artery (PDA).

Step-by-Step Code Construction:

LIMA to LAD (1 site, Arterial, from LIMA):

Section: 0 , Body System: 2 , Root Op: 1 , Body Part: 0 (One Artery), Approach: 0 (Open), Device: Z (No Device), Qualifier: 9 (Internal Mammary, Left).

Code: 02100Z9

Saphenous Vein to Diag 1, OM1, PDA (3 sites, Venous, from Aorta):

Section: 0 , Body System: 2 , Root Op: 1 , Body Part: 2 (Three Sites), Approach: 0 (Open), Device: 9 (Autologous Venous), Qualifier: W (Aorta).

Code: 021209W

Endoscopic Procurement of Left Saphenous Vein:

Section: 0 , Body System: 6 , Root Op: B (Excision), Body Part: Q (Greater Saphenous Vein, Left), Approach: 4 (Percutaneous Endoscopic), Device: Z (No Device), Qualifier: Z (No Qualifier).

  • Code: 06BQ4ZZ
  • 4. Percutaneous Coronary Interventions (PCI / Table 027)

Percutaneous Coronary Interventions (PCI) encompass balloon angioplasty, bare-metal stenting, drug-eluting stenting, and atherectomy. In ICD-10-PCS, all catheter-based coronary dilations and stent placements are classified under Root Operation 7 (Dilation) in Table 027 . ICD-10-PCS PCI Table Structure (027):

  • [0] Section ➔ Medical and Surgical
  • [2] Body System ➔ Heart and Great Vessels
  • [7] Root Op ➔ Dilation (Expanding an orifice or the lumen of a tubular body part)
  • [4] Body Part ➔ Number of Coronary Artery Sites Dilated (0, 1, 2, 3)
  • [5] Approach ➔ Percutaneous (3) [Femoral or Radial Artery Access]
  • [6] Device ➔ Stent / Intraluminal Device (4, 5, 6, 7, D, E, F, G, T, Z)
  • [7] Qualifier ➔ Bifurcation (6) or No Qualifier (Z)
  • Character 4: Number of Coronary Sites Dilated
  • 0 = Coronary Artery, One Site
  • 1 = Coronary Artery, Two Sites
  • 2 = Coronary Artery, Three Sites
  • 3 = Coronary Artery, Four or More Sites
  • Character 6: Device (Intraluminal Device Types)

The device character differentiates the mechanism and medication coating of the stent:

Drug-Eluting Stents (DES):

  • 4 = Intraluminal Device, Drug-Eluting (1 stent placed at 1 site, or generic DES)
  • 5 = Intraluminal Device, Two Drug-Eluting
  • 6 = Intraluminal Device, Three Drug-Eluting
  • 7 = Intraluminal Device, Four or More Drug-Eluting

Non-Drug-Eluting / Bare-Metal Stents (BMS):

  • D = Intraluminal Device (1 bare-metal stent)
  • E = Intraluminal Device, Two
  • F = Intraluminal Device, Three
  • G = Intraluminal Device, Four or More

Plain Balloon Angioplasty / Atherectomy (No Stent):

Z = No Device (Plain old balloon angioplasty [POBA], cutting balloon angioplasty, or laser/rotational atherectomy without stent placement)

Key PCI Coding Rules

Hierarchy of Stenting over Angioplasty: If a coronary artery site undergoes balloon angioplasty or atherectomy followed immediately by stent insertion at the same site, only the stent insertion (Dilation with Intraluminal Device) is coded . The preceding angioplasty or atherectomy is integral to the dilation and is not reported separately.

Multiple Sites with Different Devices (Guideline B4.4): If multiple coronary artery sites are dilated and treated with different devices (e.g., DES placed in LAD, and plain balloon angioplasty performed in RCA), two separate codes are assigned :

Code 1: Dilation of Coronary Artery, One Site with Drug-Eluting Intraluminal Device ( 027034Z ).

Code 2: Dilation of Coronary Artery, One Site with No Device ( 02703ZZ ).

Bifurcation Stenting: If a stent or balloon is deployed across a bifurcation lesion (e.g., carina of LAD and Diagonal), Character 7 is assigned qualifier 6 ( Bifurcation ).

Diagnostic Coronary Angiography: Catheterization of coronary arteries for diagnostic imaging (left heart catheterization, coronary arteriography) performed during the same operative episode is coded separately in Section 4 (Measurement and Monitoring) or Section B (Imaging) per inpatient facility guidelines.

5. Summary Comparison & CCS Exam Pitfalls

  • Procedure Aspect Coronary Artery Bypass Grafting (CABG) Percutaneous Coronary Intervention (PCI)
  • PCS Table 021 (Heart, Bypass) 027 (Heart, Dilation)
  • Root Operation 1 (Bypass) 7 (Dilation)

Body Part Meaning Number of distal anastomosis sites treated ( 0 – 3 ) Number of distinct vessel sites dilated ( 0 – 3 )

  • Approach Open ( 0 ) or Percutaneous Endoscopic ( 4 ) Percutaneous ( 3 )
  • Primary Device Values 9 (Venous), A (Arterial), J (Synthetic) 4 (DES), D (BMS), Z (No Device)

Harvest Coding Rule Code vein/radial harvest ( 06B... , 03B... ). Do NOT code pedicled IMA harvest. No graft harvesting involved.

  • Qualifier Role Specifies vessel bypassed from ( W Aorta, 9 LIMA) Specifies 6 (Bifurcation) or Z (No Qualifier)
  • Top 5 CCS Exam Traps for Coronary Procedures

Trap 1: Coding CABG by named vessel instead of site count. Coding separate codes for LAD and Diagonal when both were bypassed using saphenous vein from aorta. Correction: Combine them into a single code with Body Part 1 (Two Sites).

Trap 2: Forgetting graft procurement. Omitting the code for open or endoscopic saphenous vein harvesting ( 06BP0ZZ / 06BQ4ZZ ).

Trap 3: Over-coding pedicled LIMA harvest. Assigning an excision code for harvesting a pedicled LIMA. Correction: Pedicled LIMA remains attached to the subclavian artery and is not an excised free autograft; no harvest code is allowed.

Trap 4: Misinterpreting sequential grafts. Failing to count distal anastomosis sites on jump grafts (e.g., aorta to diagonal to OM = 2 sites, not 1).

Trap 5: Counting balloon prep prior to stenting as a separate code. Reporting both 02703ZZ (plain balloon) and 027034Z (DES) for the same coronary artery lesion. Correction: Assign only the stent code.