Aortic Stenosis / Aortic Sclerosis — Clinical Documentation Guide (2026)

🔍 Definition

Aortic stenosis (AS) is a structural heart disease characterized by narrowing of the aortic valve orifice, causing obstruction to left ventricular outflow. It is one of the most prevalent valvular heart diseases in adults, with a prevalence that increases significantly with age. According to the ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease, aortic stenosis is defined hemodynamically by a peak aortic jet velocity ≥ 2.0 m/s with a normal valve area of 3–4 cm² reduced to varying degrees depending on severity.

Aortic sclerosis is an important and distinct precursor condition defined by thickening, calcification, or fibrosis of the aortic valve leaflets without hemodynamically significant obstruction to outflow. By convention, aortic sclerosis does not produce a transvalvular gradient exceeding 10 mmHg and aortic jet velocity remains < 2.0 m/s. It affects approximately 25–30% of adults over age 65 and represents an independent marker of increased cardiovascular risk. Approximately 1–2% of aortic sclerosis cases progress to hemodynamically significant aortic stenosis per year, as documented in longitudinal studies referenced by the American Heart Association.

The coding distinction is clinically critical: aortic sclerosis without obstruction is typically coded to I35.8 (Other nonrheumatic disorders of aortic valve) or managed under an observation/screening Z-code framework, whereas any degree of hemodynamic obstruction (gradient > 10 mmHg; jet velocity ≥ 2.0 m/s) establishes true stenosis and warrants an AS code.

🗂️ Alternative Terminology

The following table maps formal diagnostic terms to the clinical, lay, and colloquial language commonly encountered in chart documentation. Coders and CDI specialists should recognize all variants to ensure accurate code assignment.

🩺 Signs & Symptoms

Aortic stenosis classically presents with the triad of angina, syncope, and heart failure (dyspnea). Symptom onset marks a critical prognostic threshold — untreated symptomatic severe AS carries an average survival of 2–3 years. According to UpToDate: Clinical manifestations and diagnosis of aortic stenosis in adults, key findings include:

• Angina pectoris — exertional chest pain from subendocardial ischemia due to increased oxygen demand from hypertrophied myocardium; average survival 5 years after onset
• Syncope / presyncope — exertional dizziness or loss of consciousness from inability to augment cardiac output; average survival 3 years after onset
• Heart failure / dyspnea — exertional dyspnea, orthopnea, PND due to diastolic and eventually systolic dysfunction; average survival 1–2 years after onset
• Auscultation — harsh, crescendo-decrescendo systolic ejection murmur at the right upper sternal border, radiating to the carotids; paradoxical splitting of S2; diminished or absent A2; S4 gallop
• Pulsus parvus et tardus — weak, delayed carotid upstroke on physical exam
• Reduced pulse pressure — narrow pulse pressure on BP measurement
• Signs of HF — JVD, crackles, peripheral edema, decreased exercise tolerance

Aortic sclerosis is typically asymptomatic. It may produce a soft systolic murmur (grade I–II/VI) but without hemodynamic compromise, and is often discovered incidentally on echocardiography or auscultation.

🧭 Differential Diagnosis

Accurate differential diagnosis is essential to ensure appropriate ICD-10-CM code assignment. The following conditions may mimic, co-exist with, or be confused with aortic stenosis in clinical documentation.

📋 Clinical Indicators for Coders/CDI

The following clinical indicators should prompt code assignment or a CDI query when found in chart documentation, echocardiographic reports, operative notes, or discharge summaries.

🦴 Anatomy & Pathophysiology

The aortic valve is a semilunar valve consisting of three cusps (left, right, and non-coronary) positioned at the junction of the left ventricular outflow tract (LVOT) and the ascending aorta. Its normal open area is approximately 3.0–4.0 cm². It opens during systole to permit blood ejection from the LV and closes during diastole to prevent regurgitation.

Pathophysiologic Cascade in Aortic Stenosis

1. Valve calcification / fibrosis — In degenerative (senile) AS, the process begins with lipid accumulation, inflammation, and calcification of the valve leaflets — a process akin to atherosclerosis. Risk factors mirror those of coronary artery disease: hypertension, hyperlipidemia, diabetes, age, male sex, and smoking, as described in AHA/ACC 2014 VHD Guideline (updated).
2. Progressive narrowing — As calcific deposits accumulate, leaflet mobility decreases, orifice area reduces, and a transvalvular pressure gradient develops. The LV must generate higher systolic pressure to maintain forward output.
3. Compensatory LV hypertrophy (LVH) — Chronic pressure overload triggers concentric LVH — a compensatory mechanism that initially normalizes wall stress (LaPlace’s law) and preserves LVEF.
4. Diastolic dysfunction — LVH produces impaired relaxation and increased filling pressures, causing diastolic dysfunction, often before systolic dysfunction develops. This explains why many AS patients have preserved EF even in severe disease.
5. Decompensation — Eventually the LV dilates, LVEF falls, and the patient enters low-flow low-gradient AS with poor prognosis without intervention.

Aortic Sclerosis vs. Stenosis: Progression Threshold

Aortic sclerosis exists on a continuum with stenosis. The Stewart et al. NEJM/AHA study established that any Doppler peak jet velocity < 2.0 m/s across the aortic valve defines sclerosis (non-obstructive), while ≥ 2.0 m/s with a gradient > 10 mmHg defines stenosis. Annually, about 1–2% of sclerosis cases cross this threshold.

Special Populations

• Bicuspid aortic valve (BAV): Congenitally abnormal two-cusp morphology accelerates leaflet calcification — typically presenting 10–20 years earlier than tricuspid AS. BAV also confers risk of associated ascending aortopathy.
• Rheumatic AS: Caused by post-streptococcal inflammation leading to commissural fusion rather than calcification. Almost always associated with mitral valve disease. Coded separately under I06.x per ICD-10-CM convention.
• Congenital AS: Includes valvular (Q23.0), subvalvular (Q24.4), and supravalvular (Q25.3) forms; often diagnosed in childhood or early adulthood.

💊 Medication Impact / Treatment

Currently, there are no proven medical therapies that halt or reverse the progression of calcific aortic stenosis. This distinguishes AS from conditions where medications play a primary disease-modifying role. Management is therefore focused on symptom control, risk factor optimization, and surveillance — with definitive treatment being mechanical valve replacement.

Pharmacologic Considerations

• Statins: Despite the pathophysiologic similarity to atherosclerosis, randomized trials (SALTIRE, SEAS) showed no benefit of statin therapy in slowing AS progression. However, statins remain indicated for concurrent atherosclerotic cardiovascular disease (ASCVD).
• Antihypertensives: ACE inhibitors and ARBs may be used cautiously for concurrent hypertension; however, afterload reduction must be balanced against the risk of hypotension from fixed obstruction. Beta-blockers are used for rate control in concurrent AF or to manage anginal symptoms.
• Diuretics: Used for symptom management in AS complicated by heart failure (volume overload). Document carefully, as diuretic use in AS context may indicate HF as a complication — an additional reportable diagnosis.
• Anticoagulation (warfarin / NOACs): Post-SAVR with mechanical prosthesis requires lifelong anticoagulation (typically warfarin, INR 2.5–3.5). Bioprosthetic valves and post-TAVR typically use DAPT or single antiplatelet for 3–6 months then aspirin monotherapy.
• Vasodilators: Contraindicated or used with extreme caution in severe AS — nitrates and phosphodiesterase inhibitors can cause profound hypotension due to the fixed obstruction.
• Pre-procedural medications: Dexamethasone (J1100) may be used pre-TAVR to reduce inflammatory responses. Epoetin alfa (J0881) may be used pre-operatively for anemia optimization in SAVR candidates.

Preview ends here. The full guide continues with FY2026 ICD-10-CM code sets, CPT surgical coding, MS-DRG mapping, reimbursement guidance, CDI query templates, and an audit checklist — all available to CCO Members.

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📘 ICD-10-CM Guidelines (FY2026)

The following coding guidelines apply to aortic stenosis, aortic sclerosis, and related aortic valve conditions under FY2026 ICD-10-CM Official Guidelines for Coding and Reporting.

Etiology: Rheumatic vs. Nonrheumatic

ICD-10-CM distinguishes aortic valve disease by etiology. When the documentation specifies or implies a rheumatic cause (history of acute rheumatic fever, rheumatic heart disease), codes from category I06 apply. When the valve disease is not specified as rheumatic and is presumed degenerative/calcific, category I35 applies. Per Official Guideline Section I.C.9, rheumatic origin should be coded only when documented by the provider. Coders should not assume rheumatic etiology from the presence of mitral valve disease alone.

Congenital Etiology

When aortic stenosis is documented as congenital in origin (including bicuspid aortic valve-related stenosis developing in adults), codes from Chapter 17 (Q00–Q99) take precedence over I35.x. Per ICD-10-CM Guideline Section I.C.17, congenital anomalies and malformations may be coded at any age if still being treated or affecting patient management. Q23.0 (congenital aortic stenosis) and Q23.81 (congenital bicuspid aortic valve) are appropriate for adults with these documented conditions.

Aortic Sclerosis — No Separate Stenosis Code

When documentation clearly states “aortic sclerosis” without stenosis or obstruction, assign I35.8 (Other nonrheumatic disorders of aortic valve). Do not assign I35.0 unless stenosis (hemodynamic obstruction) is documented. Per Official Guidelines, the coder should code to the highest level of specificity supported by documentation; if sclerosis has progressed to stenosis, query to clarify.

Multiple Valve Disease

When both the aortic and mitral valves are involved, or aortic and tricuspid, or all three, use codes from category I08. Category I08 assumes combined/multiple valve disease and takes precedence per the Index and Tabular instructions (see “code first” notes). Assign I08.0 for combined mitral and aortic valve diseases, I08.2 for combined aortic and tricuspid valve diseases, and I08.3 for combined mitral, aortic, and tricuspid valve diseases. Each subcode may be further combined with aortic regurgitation or insufficiency specificity.

Status Codes After Valve Replacement

Following aortic valve replacement (surgical or transcatheter), assign Z95.2 (Presence of prosthetic heart valve) or Z95.810 (Presence of automatic (implantable) cardiac defibrillator) — note: Z95.810 is for defibrillators; the correct code for TAVR status is Z95.810 if an ICD is also present, but for TAVR specifically, the presence is captured as part of Z95.2 per coding conventions. Always verify against the patient’s specific device documentation. If a re-intervention or complication occurs post-TAVR, also consult mechanical complication codes (T82.x).

Severity Documentation — CDI Critical Point

Per UHDDS and Official Guidelines, the severity of AS (mild, moderate, severe, very severe) is not distinguished in the ICD-10-CM code set for nonrheumatic AS — all grades of I35.0 share the same code. However, documenting severity is essential for: (1) HCC risk adjustment (severe AS with HF = multiple HCC capture), (2) MS-DRG differentiation when complications arise, and (3) clinical accuracy for quality measure reporting. CDI should always ensure severity is stated in the record.

🔢 ICD-10-CM Code Set (FY2026)

All codes listed are verified for FY2026 per CMS FY2026 ICD-10-CM Tabular List and CDC/NCHS ICD-10-CM files.

🔎 Indexing

The ICD-10-CM Alphabetic Index provides the following lead terms and pathways for aortic stenosis and related conditions:

• Stenosis, stenotic → aortic (valve) → I35.0
  With insufficiency → I35.2; Congenital → Q23.0; Rheumatic → I06.0; Rheumatic with insufficiency → I06.2
• Sclerosis → aortic (valve) → I35.8 (also see: Endocarditis, aortic)
• Insufficiency, aortic (valve) → I35.1; Rheumatic → I06.1; Congenital → Q23.1
• Disease → heart → aortic valve → I35.9; Rheumatic → I06.9
• Valve → aortic → bicuspid (congenital) → Q23.81
• Hypoplastic left heart syndrome → Q23.4
• Presence → prosthetic heart valve → Z95.2
• History → valve replacement → Z95.2 (for SAVR); Z95.2 or Z95.810 depending on device type for TAVR

Caution: Index entries for “Calcification, aortic” may lead to I70.0 (Atherosclerosis of aorta). Do not use I70.0 for aortic valve calcification — verify anatomy. Aortic valve calcification (without stenosis) is properly I35.8; aortic artery atherosclerosis is I70.0.

🏥 CPT (2026)

The following CPT codes are relevant for aortic stenosis/sclerosis diagnosis, monitoring, and treatment. All codes are verified for CY2026 per the AMA CPT 2026 code set.

🧾 HCPCS (2026)

HCPCS Level II codes are relevant primarily for outpatient hospital and ambulatory surgical center billing of TAVR devices and pre-procedural medications. Verify with CMS HCPCS 2026 and APC/OPPS assignments.

📚 AHA Coding Clinic (Recent Guidance)

The following guidance from AHA Coding Clinic for ICD-10-CM/PCS is relevant to aortic stenosis and valve procedures. Always verify the most current edition, as guidance is updated quarterly.

• Coding Clinic Q2 2020 / Q3 2021 — TAVR coding: Guidance confirms that TAVR is coded with replacement of the aortic valve in ICD-10-PCS with the approach (percutaneous = transfemoral). The native valve is not separately excised — TAVR deploys within the native valve; the PCS root operation is “Replacement.” Post-TAVR status is captured with Z95.2 or appropriate status code per facility policy.
• Coding Clinic — Bicuspid Aortic Valve: Q23.81 was added in FY2022 to provide specificity for congenital bicuspid AV. When a patient has both BAV (Q23.81) and concurrent aortic stenosis (I35.0), both codes should be assigned. The BAV is the underlying etiology of the stenosis and should be coded as an additional diagnosis.
• Coding Clinic — Aortic Sclerosis vs. Stenosis: Coding Clinic guidance confirms that “aortic sclerosis” without documentation of stenosis or hemodynamic obstruction should be coded to I35.8, not I35.0. Coders should not assume stenosis from sclerosis documentation alone.
• Coding Clinic — Low-Flow Low-Gradient AS: Guidance recommends querying the provider for severity classification when echocardiographic data and clinical presentation are discordant (e.g., AVA consistent with severe AS but gradient below severe threshold). The final code should reflect the clinician’s documented severity assessment.
• Coding Clinic — Rheumatic Valve Disease: When aortic and mitral valve disease coexist, coders are directed to use I08.0 (combined mitral and aortic valve disease) rather than separate I05.x and I06.x codes, when the combined code captures the documented conditions.

💰 HCC / Risk Adjustment (v28)

Under CMS-HCC Model v28 (effective 2024–2026), aortic stenosis and related valve diseases map to specific HCC categories that affect RAF scores and risk-adjusted reimbursement in Medicare Advantage and ACO/MSSP programs.

✍️ CDI Query Templates

All query templates below are written to comply with ACDIS and AHIMA compliant query standards: non-leading, multiple-choice or open-ended, clinically supported, and presented with relevant clinical indicators.

🧑‍⚕️ Treatments (Clinical)

Treatment decisions in aortic stenosis are guided by the 2021 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Intervention thresholds depend on symptom status, severity classification, LVEF, and patient surgical risk.

Surveillance (Asymptomatic AS / Aortic Sclerosis)

• Aortic sclerosis: Annual clinical evaluation; echocardiogram every 3–5 years or when symptoms develop
• Mild AS: Echocardiogram every 3–5 years; optimize cardiovascular risk factors
• Moderate AS: Echocardiogram every 1–2 years; exercise testing may be considered
• Severe AS (asymptomatic): Echo every 6–12 months; strong consideration for intervention when rapid progression, LVEF < 60%, or very high gradient (Class IIa/IIb indications per 2021 AHA/ACC)

Aortic Valve Replacement (AVR) — Intervention Thresholds

• Class I (AVR recommended): Symptomatic severe AS (any symptom from the classic triad); severe AS with LVEF < 50%; severe AS undergoing other cardiac surgery
• Class IIa (AVR reasonable): Asymptomatic very severe AS (Vmax ≥ 5.0 m/s); moderate AS undergoing other cardiac surgery; severe AS with abnormal exercise test

TAVR vs. SAVR Selection

Per the 2021 ACC/AHA guidelines and subsequent randomized trial data (PARTNER 3, Evolut Low Risk), TAVR is indicated for severe AS across all surgical risk categories in appropriate anatomy. The heart team’s shared decision-making determines TAVR vs. SAVR based on:

• Surgical risk (STS PROM score): High risk (>8%) or prohibitive → TAVR preferred; Low/intermediate risk → TAVR comparable to SAVR at 5-year outcomes
• Anatomy: Favorable femoral access, adequate annulus size, no severe calcium in LVOT
• Life expectancy: Younger patients (<65 years) may benefit from SAVR with mechanical valve for durability; older patients (>75–80) generally TAVR preferred
• BAV anatomy: Previously a relative contraindication to TAVR; now approached at experienced centers with careful planning

Balloon Aortic Valvuloplasty (BAV)

Percutaneous balloon aortic valvuloplasty (not to be confused with the condition aortic sclerosis) provides temporary relief of AS gradient. Its use is limited to bridge-to-TAVR/SAVR in hemodynamically unstable patients, or as palliative therapy in patients not candidates for definitive replacement. CPT 92986 (percutaneous BAV) applies when this procedure is performed.

Management of Post-Valve Replacement Patients

• Mechanical prosthesis: Lifelong anticoagulation (warfarin, target INR 2.5–3.5 for aortic position)
• Bioprosthetic SAVR: Antiplatelet therapy for 3–6 months, then aspirin; anticoagulation only if concurrent AF
• Post-TAVR: Dual antiplatelet therapy (aspirin + clopidogrel) for 3–6 months; then aspirin indefinitely; NOAC if concurrent AF (GALILEO trial data considered)
• Surveillance for structural valve deterioration (SVD): Serial echocardiography per guideline schedule

🎓 Patient Education / Summary

The following patient-facing summary can be used by clinical documentation specialists and educators to explain aortic stenosis and coding concepts at a lay level. It may be adapted for patient education materials.

What Is Aortic Stenosis?

The aortic valve is like a door between your heart’s main pumping chamber (left ventricle) and the large artery (aorta) that carries blood to your body. In aortic stenosis, this door becomes stiff and narrowed — usually from calcium buildup — making the heart work much harder to push blood through. Over time, this extra strain can weaken the heart and cause symptoms like chest pain, dizziness, and shortness of breath.

What Is Aortic Sclerosis?

Aortic sclerosis means the aortic valve leaflets have thickened or have some calcium deposits, but the valve opening is still wide enough that blood flows through easily. Think of it as the “early warning stage” — the valve is changing, but it’s not yet causing a blockage. About 1 in 100 people with aortic sclerosis will develop true stenosis each year. Regular monitoring with echocardiography (heart ultrasound) is recommended.

Why Does the Coding Distinction Matter for Patients?

Accurate coding ensures that your health records reflect the true severity of your condition. This affects the care plan, reimbursement for treatments, and Medicare risk scores that determine how much funding is available for your care. When doctors document severity (mild, moderate, or severe), coders and insurers can ensure the right resources are in place.

Treatment Overview for Patients

• Mild to moderate AS: Regular monitoring, heart-healthy lifestyle, management of blood pressure and cholesterol
• Severe AS with symptoms: Aortic valve replacement is typically recommended — either open-heart surgery (SAVR) or minimally invasive catheter-based procedure (TAVR)
• After valve replacement: Medications (blood thinners or antiplatelets), follow-up echocardiograms, activity guidance, and endocarditis prevention (dental prophylaxis in some cases)

About this Guide

This Clinical Documentation Guide is published by CCO Academy and is intended for credentialed coding, CDI, and clinical documentation professionals. Content is updated for FY2026 ICD-10-CM (effective October 1, 2025). All code assignments should be verified against the official ICD-10-CM Tabular List, AHA Coding Clinic, and applicable payer-specific policies. This guide does not constitute legal, medical, or compliance advice.

Last reviewed: April 2026 · Next scheduled review: October 2026 (FY2027 update)