A cerebral vascular accident (CVA), commonly referred to as a stroke, is a general term used to describe any disturbance in cerebral circulation that results in ischemia and anoxia. Stroke is a major cause of death and disability in the United States. It is also one of the top 10 conditions leading to hospital admission in the United States, involving more than 1 million hospitalizations in 1998. This column will cover various aspects of coding cerebrovascular diseases and will prepare you for questions on the certified coding specialist (CCS) or CCS-P (physician-based) exams related to them.
A stroke occurs when blood vessels carrying oxygen to a part of the brain suddenly burst or become blocked. When blood fails to get through to the affected parts of the brain, the oxygen supply is cut off and brain cells begin to die. Strokes fall into several major categories, based on whether the disrupted blood supply is caused by a blocked blood vessel (ischemic stroke) or a hemorrhage. Ischemic strokes account for 80 percent of all strokes. As part of the medical evaluation for stroke, doctors regularly use head CT to rule out hemorrhagic stroke.
Thrombosis. A blood clot (thrombus) forms inside an artery in the brain, blocking blood flow. The clot may occur in the cerebral, carotid or vertebral arteries.
Embolism. A clot, originating somewhere other than the brain, breaks loose and is carried by the blood stream to the brain. The clot reaches a point where it can go no further and plugs the vessel, cutting off the blood supply.
Subarachnoid hemorrhage. The bleeding occurs in the space between the brain and the skull.
Intracerebral hemorrhage. A defective artery within the brain bursts, flooding the surrounding brain tissue with blood.
Hemorrhagic strokes are frequently caused by aneurysms. Another cause of hemorrhagic strokes is an arteriovenous malformation (AVM), which is a cluster of abnormal blood vessels.
The symptoms of CVA vary in type, severity and permanency. Some of the symptoms eventually subside, while others are never completely resolved. Warning signs of a stroke include:
Sudden weakness or numbness of the face, arm or leg on one side of the body
Sudden dimness or loss of vision, particularly in one eye
Sudden difficulty speaking or understanding language
Sudden severe headache with no known cause
Unexplained dizziness, unsteadiness or sudden falls, especially with any of the other signs
Coding Cerebrovascular Disease
Codes from categories 430-434 should be used when coding the initial episode of care for an acute cerebral hemorrhage, occlusion, thrombosis, infarction or stroke.
430, Subarachnoid hemorrhage
431, Intracerebral hemorrhage
432, Other and unspecified intracranial hemorrhage
433, Occlusion and stenosis of precerebral arteries
434, Occlusion of cerebral arteries
The coding of strokes has been problematic for coders because the record may not be clear on whether the cause was hemorrhagic or nonhemorrhagic. In ischemic or nonhemorrhagic strokes, the artery affected should be identified. Documentation must also indicate whether or not there is an infarction. An infarct is an area of necrosis, or tissue death, due to obstruction of a blood vessel by a thrombus, embolus or a hemorrhagic or ischemic event. In hemorrhagic strokes, the site of the hemorrhage should be documented.
Codes from Categories 433, Occlusion and stenosis of precerebral arteries and 434, Occlusion of cerebral arteries use a fifth digit to indicate the presence or absence of an infarct during the current episode of care. A fifth digit of 1 is reported when there is documentation of a cerebral infarction. A fifth digit of 0 is used when a cerebral infarction is not documented. The coder should never assume that an infarction has occurred without this being clearly identified in the medical record. Always query the physician when the documentation is incomplete or unclear.
For example: A 62-year-old male is diagnosed with an acute cerebral infarction due to thrombosis. The patient also has a known history of bilateral carotid stenosis. Assign code 434.01, Cerebral thrombosis with infarction, as the principal diagnosis. Assign code 433.30, Bilateral carotid stenosis without infarction, as an additional diagnosis. The fifth digit "1" cannot be applied to the bilateral carotid stenosis because the physician has made no mention of an infarction in that specific location.
Code 436, Acute but ill-defined cerebrovascular disease, is used when the medical record documents apoplectic attack, cerebral apoplexy, apoplectic seizure or cerebral seizure.
It is very important to remember that code 436 is no longer the "default" code for CVA or stroke, not otherwise specified. Effective Oct. 1, 2004, the inclusion terms of stroke and CVA under code 436 have been removed and re-indexed to code 434.91, Cerebral artery occlusion, unspecified, with cerebral infarction. An embolic stroke or CVA will now code to 434.11, Cerebral embolism with cerebral infarction, and a thrombotic stroke or CVA will now code to 434.01, Cerebral thrombosis with cerebral infarction. With these changes, stroke and CVA not otherwise specified will always be coded as with infarction. It is very important to note that even though this is an addenda change, and does not involve code changes, it has significant consequences for the coding professional.
This change was made because physicians use the clinical terms of stroke and CVA synonymously with cerebral infarction. Records also lack specificity in the documentation and the change will allow improved uniformity and statistical data, and prevent unnecessary queries to the physician. Because coders had been accustomed to assigning code 436 for a diagnosis of CVA, when no additional information is available, care must be taken to break this habit because reimbursement will be affected.
The Medicare Grouper assigns code 434.91 to DRG 14 as it did in the previous version; however, because CVA now codes to 434.91 instead of 436 the reimbursement is higher because DRG 14 will be assigned not DRG 15.
Codes from category 437 are used to identify other and ill-defined cerebrovascular diseases such as cerebral arteriosclerosis, nonruptured cerebral aneurysms and arteritis and transient global amnesia.
Each component of the diagnosis documented by the physician identifying cerebrovascular disease should be coded unless the alphabetic index or the tabular list instructs otherwise. For example: cerebrovascular arteriosclerosis with subarachnoid hemorrhage due to ruptured aneurysm is coded to 430 and 437.0.
When codes from the 430-437 series are used, additional codes are needed to identify any sequelae or neurological deficits such as hemiplegia or aphasia. To be coded, residual neurological deficits must be present on discharge.
For example, a patient admitted because of a CVA with associate aphasia would have only the CVA code if the aphasia cleared by discharge. However, if the aphasia is still present at discharge both codes 434.91 Cerebral artery occlusion, unspecified, with cerebral infarction and 784.3, Aphasia are assigned.
If there are no residual deficits and the symptoms abated in less than 24 hours, query the physician to ascertain the diagnosis of a CVA vs. transient cerebral ischemia or attack (TIA). Use an appropriate code from the category 435, Transient cerebral ischemia, when neurological deficits are of sudden onset and brief duration due to insufficiency of cerebral circulation. The deficit may last from 5 minutes to 24 hours and is referred to as reversible. By the time of discharge, the deficits have subsided with the possible exception of some weakness. Impending CVA, intermittent cerebral ischemia and TIA are synonymous with transient cerebral ischemia.
For example: A patient is admitted because of repeated, brief episodes of light-headedness and left-sided tingling over the past week. An emergency CT scan reveals no evidence of hemorrhage, fluid collection, mass or recent infarction. The physician documents impending CVA. The correct code assignment for the principal diagnosis is 435.9, Unspecified transient cerebral ischemia.
Once a patient has completed the initial treatment or is discharged from care, codes from category 438, Late effects of cerebrovascular disease should be assigned to identify the residual neurologic deficits or late effects of cerebrovascular disease.