November 9, 2009

Coding for Cerebral Infarction
For The Record
Vol. 21 No. 21 P. 24

A cerebral infarction (ICD-9-CM code 434.91), also called a stroke or cerebrovascular accident (CVA), occurs when the blood supply to a part of the brain is slowed or interrupted and brain tissue is deprived of oxygen and nutrients, causing cells to die. Major risk factors include hypertension, smoking, and elevated cholesterol levels, but prompt treatment can decrease the complications and damage.

There are two major types of stroke: ischemic and hemorrhagic. (Code assignment may change based on stroke type.) During an ischemic stroke, not enough blood reaches the brain because arteries are blocked or narrowed. Common ischemic strokes include thrombotic stroke (434.01), or the formation of a blood clot in an artery that supplies blood to the brain, and embolic stroke (434.11), which occurs when the blood clot breaks off and travels through the bloodstream to a vessel that feeds the brain. Atrial fibrillation is a common cause of embolic strokes.

If the CVA is caused by an occlusion, narrowing, or stenosis of a precerebral artery, a code from category 433 is assigned. Common precerebral arteries include the basilar, carotid, and vertebral. The fifth digit of 1 is assigned to show that the occlusion/stenosis caused the CVA. The physician must document that the stroke occurred as a result of the occlusion or stenosis before the fifth digit of 1 can be assigned. The infarction is of the artery specified and for the current episode of care (AHA Coding Clinic for ICD-9-CM, 1995, second quarter, pages 14-15).

A hemorrhagic stroke occurs when a blood vessel in the brain leaks or ruptures. Common types include intracerebral (431), subarachnoid (430), extradural/epidural (432.0), and subdural hemorrhages (432.1).

Common stroke symptoms include the loss of balance or coordination; dizziness; slurred speech; aphasia; paralysis, numbness, or weakness on one side of the body; blurred, double, or blackened vision; and sudden, severe headache.

It is appropriate to code residuals from a new CVA when the residual is still present at the time of discharge (AHA Coding Clinic for ICD-9-CM, 1989, second quarter, page 8).

A transient ischemic attack (TIA) is a temporary interruption of the blood flow to the brain. The signs and symptoms are the same as a stroke but last for a shorter period of time, usually minutes to 24 hours, with no residual effects. Because it is difficult to decipher whether someone is experiencing a TIA or a CVA, the physician’s initial impression may well be TIA vs. CVA. For a CVA/infarct, the coder should review the medical record for neurological deficits lasting longer than 24 hours, a CT scan showing a new area of infarction or hemorrhage, and a discharge order to rehabilitation where there is no other rationale for rehab. Final code assignment is based on physician documentation, so if there is conflicting or vague documentation, query the physician for clarification. TIA defaults to code 435.9. If the physician links a patient’s TIA to a specific precerebral artery, assign the more specific diagnosis code (eg, 433.10, TIA due to carotid stenosis).

Reversible ischemic neurologic deficit (RIND) describes a CVA in which deficits such as hemiplegia, dysphagia, and slurred speech last longer than those associated with a TIA and may persist for as long as six months but will eventually resolve. A RIND may show up as a slight perfusion defect on a perfusion MRI but may not be evident at all on most imaging studies. RIND is classified to code 434.91.

Treatment for an ischemic stroke involves clot-busting drugs such as tissue plasminogen activator (tPA). tPA (99.10) needs to be administered within three hours of symptom onset. Since tPA is contraindicated in hemorrhagic strokes, a CT scan is done immediately to rule it out. tPA may significantly improve symptoms, causing the physician to document “aborted CVA.” According to coding directives, an aborted CVA is assigned to code 434.91.

Since tPA must be administered quickly, it is usually given at a community hospital emergency department (ED). The patient is then transferred to a larger facility’s stroke center, which can provide the level of services required by the increased severity of these cases. So the facility providing the tPA administration in its ED doesn’t receive increased diagnosis-related group (DRG) reimbursement because the patient is transferred before being admitted. The receiving facility is not allowed to receive reimbursement for the tPA because it was administered at another facility. Code V45.88 is assigned as a secondary diagnosis in this instance to identify whether a patient received tPA prior to admission to the receiving facility. At this time, code V45.88 does not affect Medicare-severity DRG assignment, but it is important to capture as a secondary diagnosis when appropriate.

Strokes can also be treated surgically with carotid endarterectomy (38.12), angioplasty and stents (00.62 and 00.65 or 00.61 and 00.63/00.64), aneurysm clipping (39.51), or coiling, or aneurysm embolizations (39.72, 39.75, or 39.76).

Coding and sequencing for cerebral infarction are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to more than 4,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.