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Coding in Stroke and Other Cerebrovascular Diseases

Korb, Pearce J. MD; Jones, William MD

doi: 10.1212/CON.0000000000000425
Practice Issues

ABSTRACT: Accurate coding is critical for clinical practice and research. Ongoing changes to diagnostic and billing codes require the clinician to stay abreast of coding updates. Payment for health care services, data sets for health services research, and reporting for medical quality improvement all require accurate administrative coding. This article provides an overview of coding principles for patients with strokes and other cerebrovascular diseases and includes an illustrative case as a review of coding principles in a patient with acute stroke.

Address correspondence to Dr Pearce J. Korb, University of Colorado, Leprino Building, 12401 E 17th Ave, Mail Stop L950, Aurora, CO, 80045,

Relationship Disclosure: Drs Korb and Jones report no disclosures.

Unlabeled Use of Products/Investigational Use Disclosure: Drs Korb and Jones report no disclosures.

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It is important to code accurately in the care of people with strokes and other cerebrovascular diseases not only to ensure the financial health of the practice but also to provide better patient care. The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) must be used for diagnosis- or problem-based coding.1 In addition to the diagnosis codes, Current Procedural Terminology (CPT) provides codes for Evaluation and Management (E/M) services as well as procedures.2 This article summarizes the relevant codes in ICD-10-CM, CPT codes for common and special procedures, and the issues associated with accurate documentation. A case vignette is included to illustrate these principles.

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Since the article “Coding for Telestroke” by Timothy J. Ingall, MBBS, PhD, and Bart M. Demaerschalk, MD, MSc FRCPC,3 in the 2014 Continuum Cerebrovascular Disease issue, the new ICD-10-CM, the alphanumeric coding system for clinical diagnoses, has gone live in the United States. It is far more granular than the prior edition, the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), with an expansion of codes from approximately 14,000 to 69,000. The increased specificity of codes allows for improved disease tracking. In addition to the more systemic public health rationale, ICD-10-CM may play a role in more accurate representation of disease acuity or risk when considering how value is going to play a larger part in reimbursement.4

In the transition from ICD-9-CM to ICD-10-CM, stroke and other cerebrovascular disease–related codes became much more complex. With this new code structure, over 400 different possible combinations exist for stroke. The first three characters (A12.----) are common traits, and the following characters (up to four: ---.3456) contribute increasing specificity (Coding Table 1). The cerebral infarction codes are within the common group Diseases of the Circulatory System denoted with the letter I (I00–I99). More specifically, cerebrovascular diseases are included in I60–I69, which includes I63, Cerebral infarction, the main focus of this article, and codes for hemorrhagic strokes and other forms of intracranial bleeding.

Cerebral infarction can be further codified in an increasingly specific manner. After I63, the decimal is placed and the following characters have specific clinical meaning. The fourth digit denotes mechanism (eg, embolism, thrombosis) and whether the arterial source is precerebral (extracranial) or cerebral (intracranial). Once this is established, the fifth character identifies a specific artery, if known. The sixth digit can specify laterality, if known or applicable to the localization (Coding Table 2).

The codes listed in Coding Table 2 are the most common for ischemic stroke, but less common causes of stroke and conditions are coded separately. Several conditions within other code categories, such as I67, Other cerebrovascular diseases, and I68, Cerebrovascular disorders in diseases classified elsewhere, cover strokes from other mechanisms or from other causes.

In addition, I65, Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction, is a set of analogous codes with parallel specificity (eg, artery, side). These codes are useful in encounters of transient ischemic attack (TIA) when the vascular pathology is known. Importantly, TIAs and related conditions are listed with Diseases of the Nervous System (G00–G99) instead of with Diseases of the Circulatory System (Coding Table 3). In most cases, when the pathology is known, G45, Transient cerebral ischemic attacks and related syndromes, would be coded separately as a manifestation code secondary to the main code (eg, a TIA due to stenosis of the basilar artery would be coded I65.1, Occlusion and stenosis of basilar artery, with G45.0, Vertebro-basilar artery syndrome). If the pathology is not known at the time, then G45.9, Transient cerebral ischemic attack, unspecified, could be used as a primary code.

Unlike ICD-9-CM, ICD-10-CM no longer includes a time frame for what qualifies for a condition to be considered a late effect from a stroke. If specifically managing effects of a prior stroke, use I69, Sequelae of cerebrovascular disease codes, but note that a new stroke code cannot be used concurrently (eg, I63, Cerebral infarction). Also, if a personal history of TIA or a stroke without residual deficits exists, then Z86.73, Personal history of transient ischemic attack (TIA), and cerebral infarction without residual deficits can be used (Coding Table 4). This code is also particularly useful when no deficits exist after recombinant tissue plasminogen activator (rtPA) administration.

In addition to the primary diagnosis codes, additional codes should be commonly used, if applicable to the care of stroke. When the stroke is likely contributed to by certain risk factors, their presence should be documented and coded. The most common risk factor codes are listed in Coding Table 5. If the patient has been given rtPA either in the emergency department or another facility within the past 24 hours and usually on admission, then a specific code (Z92.82) should be used by the reporting hospital (Coding Table 5). Adding the manifestation/sequelae codes, risk factor codes, and any related clinical syndromes (listed under G46, Vascular syndromes of brain in cerebrovascular diseases) to the primary codes of cerebral pathology (eg, I63, Cerebral infarction), besides the clinical value of increased specificity, may influence the Hierarchical Condition Categories risk adjustment and reimbursement in the near future.

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Coding for stroke varies according to the setting and phase of care. Specific coding issues exist depending on whether the care is delivered inpatient, outpatient, or via telemedicine.

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Inpatient Coding

Stroke is one of the most common neurologic diagnoses warranting inpatient admission; therefore, much of the care of these patients occurs in the inpatient setting.5 The majority of a stroke provider’s services fall under E/M in CPT. The fundamentals and elements of E/M coding have been covered extensively elsewhere.2,3,6,7 One should be familiar with the specific differences in documentation requirements based on the location and context of the encounter (eg, inpatient versus outpatient/emergency department, new patient versus established patient visit).

One of the three major elements of E/M is medical decision making, which is further divided into three areas: the number of conditions being addressed and their status, the amount and intensity of data reviewed or ordered, and risk. Risk may be the area most specifically important for those caring for patients with stroke. This is determined by a table of risk and is labeled minimal, low, moderate, or high. The level of risk is determined by three elements: presenting problems, diagnostic procedures, and management options selected. It should be noted that any abrupt change in neurologic status is one of the elements in presenting problems for high level of risk. This would be applicable to the first encounter in acute stroke. Drug therapy requiring intensive monitoring for toxicity is another element considered to qualify for high level of risk. The use of and monitoring of rtPA could be considered high risk, although as discussed later in this article, the acute use of the medication can be considered critical care and coded in a different way. Subsequent encounters during the admission may not qualify for high risk; the provider must use this table in addition to the other elements of medical decision making to determine risk (Coding Table 6).

If the patient is unstable and critically ill, critical care CPT codes can be used instead of or in addition to E/M codes. Several situations exist in which this could be true in the care of patients with acute stroke. Use of IV rtPA and certainly use of intraarterial rtPA and possible mechanical thrombectomy qualifies for this high probability of life-threatening deterioration. In addition to documenting this risk, critical care coding requires detailed documentation of the time spent on care. The code for the first hour of the time spent is 99291, Critical care, evaluation and management; for each additional half hour, 99292, each additional 30 minutes should be used (multiple times as applicable to the total time spent). The patient does not have to be in a critical care unit. The codes can be applied if the clinical work and patient are in any setting as long as the time spent is with the patient or immediately available at bedside (eg, physician and patient in the emergency department during rtPA and other acute care).8 If the patient is being comanaged by different specialists responsible for different aspects of care, then all can bill for critical time, but all must be considered primary providers of care (as opposed to consultants), and any time spent by a trainee does not count toward the total time.6

The case example in this article illustrates the critical nature of the care of patients with stroke and the complexity of coding. In this scenario, the provider determined and documented the critical and unstable nature of the patient having received a therapy with a high rate of complication. Assuming complete documentation of the critical status of the patient, time spent with the patient or immediately available, and a description of the work done in that time, the provider could code for critical care time. The appropriate coding for this case as presented is summarized in Coding Table 7, Scenario 1.

If the patient in the case described had not received rtPA or thrombectomy because it was outside the therapeutic window and the provider felt he was stable, spending 110 minutes of face-to-face time with him including patient care coordination and counseling, the provider then could have billed based on medical decision making or on time spent with the patient (Coding Table 7, Scenario 2). Complete documentation of a comprehensive history and examination would have warranted a level III E/M code for new patient admission (99223). Additionally, if the total time spent on patient care was at least 50% on counseling or patient care coordination, then one prolonged service code would be appropriate (99356).

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(Scenario 1) A 62-year-old right-handed man with a history of essential hypertension and tobacco use presented with the sudden onset of aphasia and severe right hemiplegia within 2 hours of onset, concerning for ischemic stroke. He underwent a stroke code in the emergency department. His National Institutes of Health Stroke Scale (NIHSS) score was 13, and his blood pressure was 162/95 mm Hg. He had no contraindications to thrombolytic therapy. He had a family history of myocardial infarction. His wife was present and was able to give urgent but informed consent. She provided a complete medical history, social history, and review of systems for the previous 2 weeks. His head CT was negative for bleeding and was both independently reviewed and discussed with the on-call radiologist. A head CT angiogram was also performed, and an occlusion of the left middle cerebral artery was found. IV recombinant tissue plasminogen activator (rtPA) was given at 2.5 hours after the last time the patient was known to be at his neurologic baseline. After the infusion, a complete screening neurologic examination beyond the NIHSS score was conducted. The patient was admitted to the medical intensive care unit for close medical and neurologic observation, with a neurologist as the primary provider in the open unit but a medical intensive care unit physician and team managing any other medical issues. All of these issues were documented, including the risk for deterioration from potential hemorrhagic complications of the rtPA. The time spent with the patient or immediately available to the bedside in the emergency department prior to transfer was also documented, which totaled 120 minutes.

If the patient in the case described had not received rtPA or thrombectomy because it was outside the therapeutic window and the provider felt he was stable, spending 110 minutes of face-to-face time with him including patient care coordination and counseling, the provider then could have billed based on medical decision making or on time spent with the patient (Coding Table 7, Scenario 2). Complete documentation of a comprehensive history and examination would have warranted a level III E/M code for new patient admission (99223). Additionally, if the total time spent on patient care was at least 50% on counseling or patient care coordination, then one prolonged service code would be appropriate (99356). The full description of codes 99223 and 99356 is as follows:

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Outpatient Coding

The principles of coding E/M for outpatient encounters are the same as for inpatient encounters. The issues of coding in the prevention of stroke have been covered in a previous Continuum article,7 with appropriate emphasis put on diagnostic specificity, inclusion of code for the effects of stroke being managed (Coding Table 4), and the importance of documentation of time spent on counseling on risk factor prevention. This is all still true; the only change is the increased specificity of ICD-10-CM, as previously discussed.

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Parity between payment of in-person care and telehealth from third-party payers is now required by law in 29 states and the District of Columbia. The statues vary from state to state in regard to the licensing requirements, types of services, and technologic restrictions.9 Despite the variable adoption of telemedicine, it is gaining acceptance and becoming eligible for reimbursement.

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Caring for patients with strokes and cerebrovascular disease is complex, especially in the acute setting. The diagnostic coding system reflects this specificity; accuracy is increasingly important as level of risk will be increasingly used in reimbursement models. The stability of the patient, level of care delivered, and setting of the care (eg, telehealth) determine the unique coding standards and should be understood to ensure compliance.

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1. Centers for Medicare & Medicaid Services, National Center for Health Statistics. International classification of diseases, tenth revision, clinical modification (ICD-10-CM). Updated June 28, 2016. Accessed December 1, 2016.
2. American Medical Association. Current procedural terminology (CPT) 2016. Chicago, IL: American Medical Association Press, 2016.
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© 2017 American Academy of Neurology