Cardiology practices are living through the most disruptive coding year in over a decade. The 2026 CPT code set introduced 418 total changes — 288 new codes and 84 deletions — with the bulk of the disruption landing directly on cardiovascular procedures, lower extremity revascularization, and electrophysiology services.

Industry benchmarks show cardiology denial rates running 8–15%, well above the 5% threshold that defines a healthy revenue cycle, with practices attempting unassisted transitions averaging 18–22% denial rate spikes in the first 90 days after the coding change took effect.

This guide breaks down exactly what changed, where the denials are actually coming from, and what to fix before another quarter of revenue disappears into a coding transition most practices haven’t fully absorbed yet.

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Part 1: The Revascularization Code Series Deletion

The single most disruptive change in 2026 cardiology billing: the entire CPT 37220–37235 lower extremity revascularization series has been deleted and replaced with 46 new bundled codes (37254–37299).

⚠️ The old codes no longer exist in payer systems. Any claim submitted with the former 37220–37235 series is rejected instantly — there’s no manual review process and no appeal pathway for the coding error itself, because from the payer’s perspective, the code simply doesn’t exist anymore.

What this means operationally:

• Every interventional cardiology and vascular practice billing lower extremity revascularization needs a complete charge capture audit aligned to the new bundling logic before the next billing cycle
• The new code set consolidates work that previously required multiple separate codes — modifier review is essential for PCI primary vessel codes that are now absorbing what used to be separate add-on codes
• EHR order sets and superbills built around the old 37220–37235 series need to be rebuilt, not patched

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Part 2: New and Reclassified Codes Worth Knowing

CPT 75577 — AI-driven coronary plaque analysis graduated from a temporary Category III code (0623T) to a permanent Category I code in 2026. Practices still submitting the old T-code are billing something payers will not cover, despite the underlying procedure being fully reimbursable under its new permanent code.

New coronary artery-specific modifiers (LD, RC, LC) now require physician notes to precisely document the specific arterial territory involved in interventional procedures — generic procedure notes that don’t specify territory will trigger downcoding or denial.

Leadless pacemaker evaluation codes were refined in 2026 to require clear documentation distinctions between interrogation, reprogramming, and follow-up — three clinically different activities that now need to be clearly separated in the note, not bundled into a single generic “device check” description.

New Category I codes for intra-aortic balloon pump procedures were added, and temporary audio-only telehealth codes were deleted, requiring practices to shift to permanent telehealth codes with full scope documentation for any cardiology telehealth encounters.

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Part 3: Where Cardiology Denials Are Actually Concentrated

Beyond the revascularization code deletion, several denial patterns are driving the elevated 2026 denial rate across the specialty:

Pattern 1 — Echo documentation gaps (CPT 93306): Payers are increasingly denying 93306 as “unbundled” when documentation doesn’t clearly establish all three required elements — 2D imaging, M-mode, and spectral/color flow Doppler. If even one component is underdocumented, the correct code is 93307, not 93306, and the revenue difference per study is significant enough that incomplete documentation is a real financial exposure, not just a coding technicality.

Pattern 2 — CCTA medical necessity denials (CPT 75574): Commercial payers and Medicare Advantage plans updated their LCDs in response to the 2024 chest-pain guideline updates, now requiring explicit pre-test probability language and documented prior workup. Dictation templates that don’t prompt for these specific elements are the direct cause of the CO-50 denial pattern in this category. Practices that update templates with these prompts have cut CO-50 denials by 40–60% within 90 days.

Pattern 3 — Calcium scoring bundling (CO-97): CPT 75571 (calcium scoring) billed on the same date as 75574 (CCTA) without the correct edit override triggers a bundling denial. In most cases, the correct approach is dropping the 75571 charge rather than fighting the bundle.

Pattern 4 — The EviCore/Cigna routing trap: EviCore by Evernorth now manages prior authorization for cardiovascular procedures for Cigna, including Cigna Medicare Advantage effective January 1, 2026 under the HealthSpring rebrand. Submitting a cardiology PA directly to Cigna when EviCore holds the review contract is a denial trigger that no amount of additional clinical documentation can fix — the claim is routed incorrectly, not clinically insufficient. This is one of the most avoidable denial categories in cardiology right now, because the fix is entirely procedural rather than clinical.

Pattern 5 — Frequency/duplicate denials (CO-18): Repeat CCTAs performed within a payer-defined lookback window (often 12–24 months) without a documented change in clinical status trigger automatic denial. When repeat imaging is genuinely appropriate, the report must explicitly state what changed clinically since the prior study — documented clinical change is what converts a CO-18 from a write-off into a payable appeal.

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Part 4: The Financial Backdrop — Why Coding Accuracy Matters More in 2026

Cardiology isn’t just absorbing a coding transition — it’s absorbing a reimbursement cut at the same time:

• The CMS-1832-F Physician Fee Schedule Final Rule implements a -2.5% efficiency adjustment
• The CMS-1834-FC OPPS Final Rule cuts indirect practice cost payments by 50%, translating to an estimated 10% reduction for high-volume procedures like TAVR and pacemaker implants
• Combined, cardiology practices are absorbing a cumulative $700 million Medicare reimbursement reduction in 2026

With margins already compressed by rate reductions, coding errors compound the problem directly — every denial or downcode now costs proportionally more against a smaller base rate than it did in 2025.

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Part 5: EP and Prior Authorization — What’s Getting Harder

Prior authorization for advanced cardiology procedures has intensified meaningfully in 2026:

• 94% of physicians report PA requirements delay patient access to care, and 31% report their PA requests are often or always denied, per the AMA’s most recent survey
• UnitedHealthcare has expanded outpatient cardiology and radiology prior auth programs multiple times in 2026, with effective dates rolling through April, May, and June — meaning a payer’s PA requirements this month may not match what they required in Q1
• TAVR, cardiac MRI, nuclear stress tests, coronary CT angiography, and most device implantations almost universally require prior authorization — the practices with the fewest denials are the ones with a dedicated PA tracking function, not billers handling PA as one task among many

The diagnostic catheterization bundling dispute: When a diagnostic catheterization is performed at the same session as a percutaneous coronary intervention (PCI), payers bundle the diagnostic study into the PCI reimbursement by default. The diagnostic cath can be billed separately only when one of three exceptions applies: no adequate-quality prior diagnostic study existed, a prior study was inadequate to plan the PCI, or a significant clinical change occurred since the prior study requiring new diagnostic assessment. Documentation needs to explicitly state which exception applies — silence on this point defaults to the bundled outcome.

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What Cardiology Practices Should Do Right Now

For the coding transition:

• Run a full charge capture audit against the new 37254–37299 bundling logic before your next billing cycle
• Rebuild EHR order sets and superbills for the deleted 37220–37235 series rather than patching them
• Confirm CPT 75577 has replaced the old 0623T Category III code across all billing templates
• Train coders specifically on the new coronary artery-specific modifiers (LD, RC, LC)

For denial prevention:

• Update echo dictation templates to explicitly prompt for all three required 93306 elements
• Build pre-test probability and prior workup language directly into CCTA order templates
• Route every Cigna cardiovascular PA through EviCore, not Cigna directly
• Document explicit clinical-status-change language for any repeat imaging within a payer lookback window

For prior authorization:

• Build a dedicated PA tracking function rather than treating it as a shared biller responsibility
• Reverify UnitedHealthcare’s current PA requirements quarterly given how frequently they’ve changed in 2026
• Document which of the three bundling exceptions applies whenever billing a diagnostic cath separately from same-session PCI

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Final Thoughts

2026 is not a routine coding update year for cardiology — it’s a structural rebuild of how the specialty’s highest-volume procedures are billed, arriving at the same time as a meaningful reimbursement cut. Practices treating this as “update the encoder and move on” are the ones showing up in the 18–22% denial rate spike statistics. Practices that invested in a real charge capture audit, rebuilt documentation templates, and fixed the EviCore routing issue are the ones holding denial rates near the 5% benchmark despite everything else moving at once.

At ClaimsXperts, we help cardiology practices navigate the 2026 CPT restructuring, EviCore/Cigna routing, and documentation requirements driving this year’s elevated denial rates — building revenue cycle workflows around what payers actually require today, not what worked under the old code set.

Contact us today at https://www.rcmmasters.com/#contactus to learn how ClaimsXperts can support your cardiology practice through this transition.

ClaimsXperts is a Revenue Cycle Management company based in Frisco, TX, serving medical practices across the United States. We specialize in medical billing, coding, and insurance credentialing for solo practitioners, group practices, and specialty clinics.