ICD-10 Code I35.0: Nonrheumatic Aortic Stenosis

Key Takeaways

I35.0 codes nonrheumatic aortic stenosis requiring valve replacement

Z95.2 documents prosthetic valve presence after procedure

Z95.4 applies to other heart-valve replacement types

DRG 266/267 determine reimbursement for TAVR procedures

POA exemption applies to Z95.2 and Z95.4 status codes

Understanding Aortic Valve Replacement ICD-10 Codes

Aortic valve replacement procedures require precise ICD-10-CM coding to support accurate reimbursement and clinical documentation. The primary diagnosis codes I35.0 (Nonrheumatic Aortic Stenosis) and I35.1 (Nonrheumatic Aortic Insufficiency) capture the underlying valve pathology driving intervention need. After the procedure, status codes Z95.2 and Z95.4 document the presence of prosthetic or replacement valve hardware.

According to the CMS ICD-10-CM coding guidelines, these codes integrate with ICD-10-PCS procedural codes and DRG assignment logic to determine payment rates for both transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR). Documentation quality directly impacts risk adjustment calculations and mortality benchmarking.

ICD-10-CM Codes for Aortic Valve Conditions

The I35 category captures nonrheumatic aortic valve disorders, distinguishing structural pathology from rheumatic disease sequelae. Each code maps to specific clinical presentations and procedural indications.

Aortic Valve Replacement ICD-10 Code I35.0: Nonrheumatic Aortic Stenosis

I35.0 is the billable ICD-10-CM code for nonrheumatic aortic valve stenosis, capturing narrowing of the aortic valve orifice without inflammatory or rheumatic etiology. According to ICD10Data.com, this code became effective October 1, 2025, and supports reimbursement claims across all payer types. Clinicians document severity using echocardiographic criteria: mild stenosis shows a mean gradient under 25 mmHg, moderate shows 25-40 mmHg, and severe exceeds 40 mmHg with valve area below 1.0 cm².

Critical stenosis, where valve area falls below 0.6 cm², triggers consideration for intervention. When patients present with symptomatic severe stenosis-manifested as exertional dyspnea, angina, or syncope-the combination of I35.0 with appropriate symptom codes justifies procedural necessity. Documentation must capture functional limitation severity to support risk stratification.

Aortic Valve Replacement ICD-10 Code I35.1: Nonrheumatic Aortic Insufficiency

I35.1 codes nonrheumatic aortic regurgitation, where the valve fails to close completely during diastole, allowing backflow into the left ventricle. The AAPC classification system places this within the cardiovascular disease chapter, distinct from rheumatic valve disorders. Acute presentations differ markedly from chronic compensated regurgitation-acute severe insufficiency manifests as cardiogenic shock, while chronic cases progress through asymptomatic left ventricular remodeling before decompensation.

Regurgitation severity grades from mild to severe using color Doppler jet width and vena contracta measurements. Documentation should specify acute versus chronic presentation, as this distinction influences procedural urgency and DRG assignment. Chronic severe insufficiency with left ventricular systolic dysfunction (ejection fraction below 50%) represents a class I indication for intervention regardless of symptom status.

I35.9: Nonrheumatic Aortic Valve Disorder, Unspecified

I35.9 serves as the fallback code when aortic valve pathology exists but insufficient documentation prevents assigning I35.0 or I35.1. According to the WHO ICD-10 classification, unspecified codes should trigger documentation improvement queries rather than routine use. When echocardiography reports describe “aortic valve disease” without quantifying stenosis or regurgitation severity, coders default to I35.9 pending clarification.

Practices should audit I35.9 utilization rates quarterly. Frequent use signals workflow gaps where imaging findings aren’t translating into structured clinical documentation. Implementing echo report templates with mandatory severity grading fields reduces unspecified code reliance and improves risk adjustment accuracy.

ICD-10-CM Status Codes for Post-Procedure Documentation

After aortic valve replacement, Z codes document the presence of prosthetic hardware as a permanent patient characteristic. These status codes appear on all subsequent encounter claims, influencing both clinical decision-making and administrative processes.

Aortic Valve Replacement ICD-10 Code Z95.2: Presence of Prosthetic Heart Valve

Z95.2 codes the presence of a prosthetic heart valve, encompassing both mechanical and bioprosthetic implants. According to CMS guidelines, this code is exempt from present-on-admission (POA) reporting requirements, as the valve presence predates the current admission by definition. The code applies regardless of valve type-mechanical tilting disc, bileaflet, bioprosthetic porcine, or bovine pericardial valves all map to Z95.2.

Documentation must specify valve position (aortic, mitral, tricuspid, or pulmonary) in the clinical narrative, though ICD-10-CM doesn’t require position-specific Z codes. When patients with prosthetic valves present for unrelated conditions, Z95.2 appears as a secondary diagnosis, alerting providers to anticoagulation considerations and endocarditis prophylaxis protocols. The code persists on all claims until valve removal or death.

Aortic Valve Replacement ICD-10 Code Z95.4: Presence of Other Heart-Valve Replacement

Z95.4 captures heart-valve replacements that don’t meet the prosthetic valve definition under Z95.2. This includes transcatheter valve-in-valve procedures, where a new valve deploys within a failing bioprosthetic valve, and certain rapid-deployment valve systems. The AAPC coding resource clarifies that Z95.4 also exempts from POA reporting, matching Z95.2’s administrative handling.

The distinction between Z95.2 and Z95.4 matters for risk adjustment models and outcomes registries, which track valve type performance separately. When documenting transcatheter aortic valve replacement (TAVR) cases, many practices default to Z95.2 despite Z95.4’s technical accuracy for certain valve configurations. Cardiology practices should standardize which code applies to self-expanding versus balloon-expandable transcatheter valves to maintain data consistency.

Aortic Valve Replacement Chart: Code Selection by Clinical Scenario

Code selection follows clinical severity and procedural type. When stenosis and insufficiency coexist, the dominant hemodynamic lesion takes precedence as the primary diagnosis. TAVR procedures typically pair I35.0 with Z95.4, while surgical replacements pair I35.0 or I35.1 with Z95.2 for mechanical or bioprosthetic valves.

DRG Assignment and Reimbursement for Aortic Valve Replacement Procedures

Diagnosis-related group (DRG) assignment for aortic valve replacement depends on procedural approach and complication presence. According to the CMS MS-DRG Definitions Manual version 38.1, DRG 266 and 267 govern endovascular cardiac valve replacement procedures, with DRG 266 capturing cases with major complications or comorbidities (MCC) and DRG 267 covering cases without MCC.

TAVR procedures map to DRG 266/267 when ICD-10-PCS codes 02RF* (replacement of aortic valve, percutaneous approach) appear with I35.0 or I35.1. Surgical open aortic valve replacement maps to different DRG categories (216-221) depending on cardiopulmonary bypass use and coronary artery bypass grafting concurrency. The payment differential between transcatheter and surgical approaches reflects resource intensity-TAVR cases average 3-5 inpatient days versus 7-10 days for surgical cases.

Risk adjustment models incorporate I35.0 and I35.1 codes when calculating expected mortality and complication rates. Practices treating higher acuity patients with critical aortic stenosis benefit from precise severity documentation, as this justifies deviation from benchmark mortality rates. The presence of Z95.2 or Z95.4 in subsequent admissions alerts risk stratification algorithms to prosthetic valve complication potential.

ICD-10-PCS Procedural Codes for Aortic Valve Replacement

ICD-10-PCS codes document the procedural approach, valve type, and access route for aortic valve replacement. These codes integrate with diagnosis codes to determine DRG assignment and support medical necessity validation. The New Technology Section (Section X) contains codes for novel valve systems and deployment methods.

Transcatheter aortic valve replacement uses 02RF* root codes, where the fourth character specifies approach: 3 for percutaneous, 4 for percutaneous endoscopic. The sixth character identifies valve type: J for synthetic substitute, autologous tissue substitute, or zooplastic tissue. Rapid-deployment valve systems may map to X2RF* codes in the New Technology Section, which bundle device and procedure into a single code structure.

Surgical aortic valve replacement uses 02RF0** codes, where the third character 0 specifies open approach. When coronary artery bypass grafting occurs concurrently, additional ICD-10-PCS codes from the 021* series document the bypass procedure. Documentation must explicitly state whether cardiopulmonary bypass occurred, as this detail influences both procedural coding and DRG assignment logic.

Practices performing both TAVR and surgical valve replacement should maintain separate claims management workflows for each approach, as coding requirements and prior authorization processes differ substantially between percutaneous and open surgical methods.

Streamline Aortic Valve Coding Workflows

Integrate ICD-10-CM diagnosis codes with procedural documentation using Pabau's structured clinical note templates. Automated coding suggestions reduce claim errors and improve DRG assignment accuracy.

Book a demo

Documentation Requirements for Aortic Valve Replacement Claims

Medical necessity documentation for aortic valve replacement claims requires quantified echocardiographic measurements, symptom severity classification, and functional status assessment. The CDC ICD-10-CM coding tool emphasizes that qualitative descriptions like “moderate stenosis” without gradient values fail to support I35.0 coding specificity.

Echocardiography reports must include peak velocity, mean pressure gradient, calculated valve area, and dimensionless velocity index. When dobutamine stress echocardiography occurs to assess low-flow low-gradient stenosis, document both baseline and stress hemodynamics. For aortic insufficiency, vena contracta width, regurgitant volume, and regurgitant fraction quantify severity and justify I35.1 assignment.

Symptom documentation should reference New York Heart Association (NYHA) functional class, with specific examples of activity limitation. “NYHA Class III: dyspnea with routine daily activities such as dressing or walking 20 feet” provides stronger medical necessity support than “symptomatic aortic stenosis.” When patients are asymptomatic despite severe stenosis, document left ventricular dysfunction (ejection fraction below 50%) as an alternative intervention trigger.

Pre-procedure risk assessment using STS (Society of Thoracic Surgeons) scores influences TAVR versus surgical approach selection and should appear in documentation supporting procedural choice. Document contraindications to surgery-such as porcelain aorta, prior chest radiation, or prohibitive frailty-when TAVR represents the only viable option. This supports medical necessity even when procedural risk scores fall within surgical range.

Common Coding Errors and Audit Triggers

The most frequent aortic valve replacement coding error involves conflating pre-procedure diagnosis codes with post-procedure status codes. I35.0 or I35.1 should never appear on claims after valve replacement unless native valve disease persists in a different position. Once the aortic valve replacement occurs, Z95.2 or Z95.4 replaces the acute pathology code on all subsequent encounters.

Another common error pairs surgical aortic valve replacement ICD-10-PCS codes with transcatheter valve DRG assignments. When 02RF3* or 02RF4* codes (percutaneous approaches) appear with surgical CPT codes like 33361, payer systems flag the claim for manual review due to approach mismatch. Cardiology practices performing hybrid procedures must document whether the primary approach was percutaneous or open surgical to guide code selection.

Audit triggers fire when Z95.2 or Z95.4 codes appear without corresponding prior procedural claims in the patient’s history. Payers cross-reference status codes against surgical procedure databases, and discrepancies prompt documentation requests. When patients transfer from other health systems with existing prosthetic valves, obtain operative reports from the original implanting facility to substantiate status code use.

Practices should implement compliance management workflows that cross-check diagnosis codes against procedural codes before claim submission, automatically flagging mismatches for coder review before they reach payer systems.

Clinical Scenarios Requiring Modifier or Complication Codes

When aortic valve replacement occurs during the same admission as another major cardiovascular procedure, modifier usage and sequencing rules determine reimbursement. If coronary artery bypass grafting occurs concurrently with surgical valve replacement, both procedures receive separate ICD-10-PCS codes, and DRG assignment shifts to combination procedure categories (DRG 216-218) with higher reimbursement rates.

Valve-in-valve TAVR procedures-where a transcatheter valve deploys within a failing bioprosthetic surgical valve-require both Z95.2 (documenting the original surgical valve) and an acute diagnosis code explaining the indication for repeat intervention. Common scenarios include structural valve degeneration (I35.0 if stenosis develops, I35.1 if regurgitation), prosthetic valve endocarditis (I33.0), or paravalvular leak (T82.03). The valve-in-valve procedure receives distinct ICD-10-PCS coding reflecting the modification of existing prosthetic hardware.

When complications occur during or after aortic valve replacement, additional ICD-10-CM codes capture these events and influence risk-adjusted outcomes reporting. Major complications include stroke (I63.*), acute kidney injury (N17.*), major bleeding (I97.418), or cardiac tamponade (I97.19). These complication codes should appear with present-on-admission indicators to distinguish pre-existing conditions from procedural complications.

Practices submitting claims to multiple payers should verify each payer’s specific coding requirements for valve-in-valve procedures, as some commercial insurers apply proprietary modifiers beyond standard CMS guidelines. Maintaining payer-specific coding matrices within your digital documentation system reduces claim rejection rates for these complex scenarios.

Expert Picks

Need cardiology-specific coding workflows? Dermatology EMR Software offers structured templates adaptable to cardiovascular procedure documentation.

Looking for automated coding validation? Echo AI reviews clinical notes and suggests appropriate ICD-10-CM codes based on documented findings.

Managing multi-specialty coding teams? Team Management Software assigns coding tasks by specialty and tracks claim accuracy metrics per coder.

Conclusion

Accurate ICD-10-CM coding for aortic valve replacement procedures requires distinguishing pre-procedure diagnosis codes (I35.0, I35.1, I35.9) from post-procedure status codes (Z95.2, Z95.4). Documentation quality directly impacts DRG assignment, risk adjustment calculations, and medical necessity validation. Practices should implement structured echocardiography report templates that mandate quantified severity measurements, reducing reliance on unspecified codes and improving claim acceptance rates.

As transcatheter valve technology evolves and rapid-deployment systems expand, coding guidelines will continue adapting to capture novel device types and procedural approaches. Maintaining awareness of ICD-10-CM annual updates and New Technology Section additions ensures coding accuracy for emerging valve replacement methods. Regular audits of Z code utilization patterns identify documentation improvement opportunities before payer audits flag discrepancies.

Frequently Asked Questions