Cardiology is one of the most complex specialties for bundling rules and National Correct Coding Initiative (NCCI) edits. Diagnostic imaging, physiological testing, invasive procedures, and device management all have strict rules that determine which services may be billed together and which are considered mutually exclusive, inclusive, or unbundled.
This guide provides a complete explanation of bundling logic, cardiology-specific NCCI edit patterns, correct modifier usage, and documentation requirements to avoid avoidable denials or audit exposure.
Understanding NCCI Edits in Cardiology
The National Correct Coding Initiative edits govern:
- Which CPT codes can and cannot be billed together
- When a modifier can override the edit
- When services are always bundled, regardless of documentation
Two major NCCI edit types apply:
1. Column 1 / Column 2 (Comprehensive/Component)
- Column 1 = Comprehensive service
- Column 2 = Component service
- If both are billed together → Column 2 is denied unless a modifier is allowed.
2. Mutually Exclusive Edits
Two procedures cannot logically occur in the same session or the same anatomic area. No modifier can override these edits.
Guiding Principles of Cardiology Bundling
Cardiology bundling rules apply across the following categories:
1. Diagnostic tests bundled into procedures if used solely to guide intervention
Example:
- Diagnostic coronary angiography may NOT be billed if performed only to guide a planned PCI.
2. Imaging guidance is bundled into most interventional cardiology procedures
Fluoroscopy, catheter placements, and guidance codes are usually included.
3. Therapeutic procedures include related preparation and post-treatment work
E.g., stent placement includes angioplasty in the same vessel.
4. Multiple vessels have territory-specific bundling rules
Different in coronary vs peripheral vascular coding.
5. Physiologic testing is bundled when used intra-procedurally
E.g., ECG monitoring during stress tests or catheter procedures.
Understanding these rules prevents double-billing and incorrect use of modifiers.
Coronary Artery Bundling Rules (PCI + Cath Lab Procedures)
Coronary intervention codes (92920–92944) have strict bundling.
Rule 1: Angioplasty is bundled into stent placement
If angioplasty and stent occur in the same coronary artery:
- Bill only the stent code (e.g., 92928)
Rule 2: Atherectomy includes angioplasty
If both are performed in the same vessel:
- Bill only the atherectomy code (92924)
Rule 3: Diagnostic coronary angiography is bundled if performed to guide PCI
Diagnostic cath (93454–93461) is separately billable only when:
- No recent cath exists OR
- Patient’s condition changed OR
- Findings were previously unknown
- AND
- The decision to perform PCI was made after a diagnostic study
If PCI was planned, → diagnostic cath becomes bundled.
Rule 4: FFR, IVUS, and OCT are separately billable but require medical necessity
They must be:
- Performed in a different vessel from the PCI OR
- Performed in the same vessel but for a separate purpose
Examples:
- FFR proving intermediate lesion significance
- IVUS/OCT to assess stent under-expansion
Rule 5: Bundling of S&I and catheter placement
Diagnostic imaging supervision & interpretation, and most catheter placements are included in PCI codes.
Peripheral Vascular Bundling Rules (PVI)
Peripheral vascular interventions have more complex rules because of the territories.
PVI Territories:
- Iliac
- Femoral–Popliteal
- Tibial–Peroneal
Rule 1: One “initial” code per territory
Each territory allows:
- 1 initial code
- Multiple add-on codes for additional distinct vessels
Rule 2: Stent and atherectomy include angioplasty
- Iliac: 37221 includes angioplasty
- Fem-pop: 37226 includes angioplasty
- Tibial-peroneal: 37232 includes angioplasty
Rule 3: Atherectomy + stent in same vessel
Use combination codes:
- 37227 (fem-pop)
- 37235 (tibial-peroneal)
Rule 4: Catheter placement + imaging often bundled
If diagnostic angiography is performed strictly to guide intervention → bundled.
Rule 5: Add-on codes require clear vessel documentation
Auditors deny many claims due to:
- Missing vessel segments
- Ambiguous anatomy
Non-Invasive Cardiology Bundling Rules
1. ECG + E/M Bundling
ECGs performed at the same visit as an E/M evaluation are often separately payable, but documentation must support:
- Medical necessity
- Interpretation
- Report
However, some payers bundle routine ECGs performed during visits.
2. Echo Bundling
- 93306 includes Doppler + Color
- Do not add 93320/93325 when billing 93306
- 93308 (limited echo) cannot be billed the same day as a full echo unless modifiers and documentation justify a separate clinical need
3. Stress Test Bundling (93015–93018)
Common bundled elements:
- ECG monitoring
- Blood pressure recordings
- Continuous supervision
Stress echo (93350/93351) bundles stress test ECG components unless split into 93350 + 93018 based on payer rules.
4. Holter vs Extended ECG Bundling
Same-day combinations trigger denials if:
- Overlapping monitoring periods
- Same service duplicated with different device types
Electrophysiology (EP) Bundling Rules
EP procedures have multiple layers of bunding.
Rule 1: EP study (93620, 93619) bundles into most ablation procedures
When ablation is performed:
- A comprehensive EP study is considered included
- Don’t bill 93620 separately unless documentation proves a separate diagnostic purpose
Rule 2: Mapping Codes (93609, 93613)
3D mapping is usually separately billable if performed for:
- Complex arrhythmias
- Additional clarity
- Pre-ablation planning
But mapping is bundled when:
- It is integral to the ablation.
- Documentation states “mapping performed to guide ablation.”
Rule 3: Intracardiac Echo (ICE)
- 93662 is separately billable
- Must show:
- Indication
- Utility
- Interpretation
Rule 4: Cardioversion
Cardioversion performed during EP ablation is often bundled.
Pacemaker/ICD Bundling Rules
Rule 1: Pocket creation is bundled
Pocket formation is included in:
- New generator insertion
- Replacement
- Add-on lead insertion
Rule 2: Lead testing is bundled
Threshold, impedance, and sensing measurements are included.
Rule 3: Lead repositioning vs replacement
- Replacement = removal + insertion → billable
- Repositioning is separately billable (33215), but not if performed solely to fix the new implant position during the same surgery.
Rule 4: Programming vs interrogation
- Programming must include parameter changes.
- Interrogation alone does not justify programming code.
Diagnostic Angiography Bundling: Cardiology-Specific Rules
Diagnostic imaging is the most commonly audited bundling category in cardiology.
Diagnostic Angiography May Be Billed Separately IF:
- No prior study exists.
- Disease progression suspected
- Symptoms worsened
- Different vascular territory
- Prior study unavailable or inadequate
Diagnostic Angiography May NOT Be Billed If:
- Performed solely to plan an already-known PCI/PVI
- Part of routine pre-procedure preparation
- Used only to confirm prior findings
Documentation MUST explicitly state:
- Why the study was needed
- Medical necessity
- New information discovered
- How it changed management
Modifier Use With NCCI Edits
Correct modifier use is crucial to override certain NCCI edits.
Modifier 59 — Distinct Procedural Service
Used when:
- Different vessel
- Separate site
- Different session
- Different lesion
Better alternatives:
- XS (separate structure)
- XE (separate encounter)
- XP (separate practitioner)
- XU (unusual service)
Modifier 25 — Significant, Separately Identifiable E/M
Common audit trigger—use only when:
- E/M is unrelated to procedure
- Must include different diagnoses and a plan
Modifier 26/TC — Professional vs Technical
Used when:
- Imaging is interpreted by one party
- The technical side is performed by another
Modifier RT/LT
Required for:
- Vascular ultrasounds
- Peripheral studies
- Lower/upper extremity interventions
Modifiers must match:
- Anatomy
- Side
- Vessel
- Documentation
Common Cardiology NCCI Edit Examples
Below are the most frequent NCCI edits affecting cardiology:
1. PCI + Diagnostic Cath
Most diagnostic cath codes are Column 2 edits when PCI is performed.
Requires a modifier only if documentation supports separate medical necessity.
2. Echo + Doppler Add-Ons
93306 bundles:
- 93320
- 93325
3. Stress Test + Stress Echo
93351 bundles 93015.
4. EP Study + Ablation
93620/93619 bundled with ablation codes (93653–93656).
5. Fluoroscopy Bundled Into Procedures
Cardiology procedures bundle fluoroscopy (e.g., 76000).
6. Catheter Placement Bundled Into PCI
Catheter placement codes (36215–36248) are not billable with PCI.
7. Vascular Ultrasound + ABI
Certain ABI services are bundled into duplex vascular studies.
8. Pacemaker/ICD Repositioning
Repositioning sometimes bundles into revision/replacement depending on the scenario.
Documentation Requirements to Support Bundling Exceptions
When unbundling is justified with modifiers, documentation must include:
1. Clear, separate indications
Symptoms, risks, vascular territory differences.
2. Explicit statement of new findings
Especially for diagnostic cath.
3. Vessel/segment specificity
For PVI and PCI.
4. Decision-making rationale
Why was another study or intervention needed?
5. Technical elements NOT included in global or bundled service
E.g., separate imaging or mapping is not integral to the procedure.
High-Risk Denials Caused by Bundling Errors
1. Diagnostic cath billed with PCI without justification
Most common denial in cardiology.
2. Echo billed improperly with Doppler add-ons
3. Multiple imaging tests billed on the same day without necessity
E.g., echo + nuclear + ABI without a valid reason.
4. PVI codes billed without correct initial/add-on relationships
5. Improper use of modifier 59/XS to force payment
Conclusion
Cardiology bundling and NCCI edit rules are some of the most complex across all medical specialties.
Accurate coding requires understanding which diagnostic tests, imaging services, procedural components, and catheterizations are considered bundled versus separately reportable. Proper modifier use and strong documentation help support valid exceptions. Many practices create internal bundling checklists and workflows or collaborate with specialized RCM partners—such as Global Tech Billing LLC—to maintain compliant, audit-proof cardiovascular billing systems.
FAQs
1. What are NCCI edits in cardiology?
They are coding rules that prevent billing two services together when one is a component of another or when procedures are mutually exclusive.
2. When is diagnostic coronary angiography separately billable during PCI?
Only when medical necessity is documented, and the decision for PCI was made after the diagnostic study.
3. Are catheter placements separately billable during PCI?
No. Catheter placements are bundled into PCI.
4. Is angioplasty separately billable when a stent is placed?
No. Stent placement includes angioplasty in the same vessel.
5. Can EP study codes be billed with ablation?
Typically no. They are bundled into most ablation codes.
6. Are Doppler add-ons allowed with 93306?
No. 93306 already includes Doppler and color flow.
7. How should modifiers 59/XS be used?
Only when interventions occur in separate vessels, structures, or sessions.
8. Why are bundling errors common in PVI?
Because of territory-based coding and improper identification of initial vs add-on vessels.
