Occlusion and stenosis of the left carotid artery is a clinical condition characterized by the narrowing or complete blockage of the left common or internal carotid artery. This is most frequently caused by the progressive accumulation of atherosclerotic plaque within the arterial walls. The narrowing restricts blood flow to the left cerebral hemisphere, significantly increasing the risk of ischemic cerebrovascular events, including transient ischemic attacks (TIAs) and ischemic strokes. Stenosis is typically graded by the percentage of luminal reduction (e.g., mild <50%, moderate 50-69%, or severe 70-99%) using non-invasive imaging like carotid duplex ultrasound, computed tomography angiography (CTA), or magnetic resonance angiography (MRA). In the 2026 ICD-10-CM coding system, this code specifically excludes cases where the occlusion or stenosis has already resulted in a cerebral infarction (I63.-). Management strategies depend on the degree of stenosis and the presence of symptoms, often involving antiplatelet therapy, high-intensity statins, and potentially surgical revascularization via carotid endarterectomy (CEA) or carotid artery stenting (CAS).
Distinguish between occlusion and stenosis and specify the percentage of luminal narrowing.
Example: Patient presents for follow-up of left internal carotid artery stenosis. Carotid duplex ultrasound reveals 70 to 99 percent stenosis of the left internal carotid artery, documented as hemodynamically significant. This finding supports the medical necessity for planned surgical intervention and confirms the diagnosis of I65.22 rather than a less specific atherosclerosis code.
Billing Focus: Laterality and severity (percentage of narrowing).
Document whether the patient is symptomatic or asymptomatic relative to the carotid stenosis.
Example: The patient is currently asymptomatic with no history of TIA or stroke but is diagnosed with significant left carotid artery stenosis (I65.22). Documentation of the asymptomatic status is crucial for justifying prophylactic carotid endarterectomy under current clinical guidelines.
Billing Focus: Clinical manifestation status (asymptomatic vs. symptomatic).
Explicitly link carotid stenosis to any current neurological deficits if an infarction has occurred.
Example: Patient has left-sided carotid stenosis causing a right-sided hemiparesis due to a previous cerebral infarction. Diagnosis updated to I63.232 (Cerebral infarction due to occlusion and stenosis of left carotid artery) with residual I69.351 (Hemiplegia and hemiparesis following cerebral infarction affecting right dominant side) to show the causal link.
Billing Focus: Causal relationship between the stenosis and the resulting neurological condition.
Report specific atherosclerotic risk factors such as tobacco use or hyperlipidemia alongside the carotid diagnosis.
Example: Left carotid artery stenosis (I65.22) in a patient with a 40 pack-year history of cigarette smoking (F17.210) and type 2 diabetes mellitus with diabetic chronic kidney disease (E11.22). Comprehensive documentation of these comorbidities supports the overall complexity of management.
Billing Focus: Co-occurring chronic conditions and lifestyle factors.
Clarify the specific branch of the carotid artery involved when imaging results are available.
Example: MRA of the neck confirms occlusion of the left internal carotid artery at the bulb. The patient also has mild atherosclerotic narrowing of the left common carotid. Primary diagnosis remains I65.22 focusing on the high-grade left internal carotid occlusion.
Billing Focus: Anatomical specificity (Internal, Common, or External carotid).
Primary diagnostic tool to quantify the degree of stenosis in I65.22.
The standard surgical treatment for significant left carotid stenosis (I65.22).
Alternative to endarterectomy for treating I65.22, particularly in high-risk surgical patients.
Used for precise mapping of the stenosis prior to endovascular intervention.
Used for monitoring stable, asymptomatic carotid stenosis that does not require immediate intervention.
Appropriate for patients with high-grade stenosis (I65.22) requiring coordination of specialist care or medication adjustments.
Required for a patient with symptomatic I65.22 presenting with recurrent TIAs necessitating emergent surgical referral.
Standard code for a new patient referred for a recently discovered carotid bruit and ultrasound-confirmed I65.22.