Cardiology Coding Alert

Attack Fourth and Fifth Digits for Myocardial Infarction Dx

Avoid using 'unspecified' by investigating chart

Rather than falling back on an unspecified code for a myocardial infarction (MI) diagnosis when you don't have enough information, remind your cardiologist to note when the MI happened and where the damage occurred.
When the physician documents these two aspects of the MI, you can easily choose the correct diagnosis code, including the required fourth and fifth digits.

Choose 410 Series for Acute MI

A patient has an MI (commonly known as a heart attack). Your cardiologist sees the patient in the hospital, the office or another setting during the eight weeks immediately following the MI. You should code the diagnosis using the 410 series (Acute myocardial infarction), with required fourth and fifth digits.
"When coding an MI, it's always nice to have information on the exact location and episode of care, but we don't always get it," says Joanna Anderson, CPC, billing manager and coder at Peninsula Cardiology Associates in Salisbury, Md.
Don't fall for "unspecified": You may look to 410.90 (Acute myocardial infarction; unspecified site and episode of care) if you lack necessary documentation, but don't fall into that trap.
"For cardiology specialists, my suggestion is that you never use the unspecified code," says Nancy Emerick, coder at North Ohio Heart Center in Avon, Ohio. "A cardiologist should be able to determine from a combination of diagnostic testing the specific location of an MI. And you should talk with your physician regarding the importance of both the location and the episode of the MI."
What you need to know: You need to figure out where the MI occurred in order to pick the correct fourth digit, ranging from 0 (Of anterolateral wall) to 9 (Unspecified site). You also have to decide on a fifth digit. Your options are 0 (Episode of care unspecified), 1 (Initial episode of care), or 2 (Subsequent episode of care).

Find Out Where for 'MI'

If the cardiologist documents only "MI," you may have to don a Sherlock Holmes hat and do some investigating.
One tactic is to check for an emergency department note. "If I had at least an ED note, I could look at the EKG findings (such as elevation in the inferior and lateral leads) and query either the attending physician who saw the patient or a cardiologist to see if the findings in the ED note are consistent with, for example, an inferiolateral MI," says Sharon Threadgill, medical record technician and inpatient coder for the Department of Veteran Affairs Medical Center in Salem, Va.
You may also want to check for a cardiac catheterization, coronary angioplasty, echocardiography, or even a nuclear perfusion scan report in the chart, but make sure you confirm the MI location with your cardiologist or the attending physician.
However, if the patient presents with symptoms and positive test results, and your cardiologist only documents "MI" (without stating the site or episode of care), you can opt to use 410.90, Anderson says.

Focus on When for 'History of MI'

A patient has no cardiac symptoms three months after her MI and is returning for a checkup. Your cardiologist writes "history of MI" without noting when the MI occurred.
In this case, you should watch your documentation to see if "in fact, the MI is an old MI and the physician is using the terminology 'history of MI' when it is a current condition," Threadgill says. You should use 412 (Old myocardial infarction) for a healed MI or past MI diagnosed using an EKG or other means but the patient presents with no current symptoms.
Important: You should check with your cardiologist or your documentation to see when the MI occurred. For example, if the MI occurred seven weeks ago, you should use the 410 series. If the MI is much older and the patient has no related symptoms, the MI may fit the criteria for 412.
Note: You can also use 412 as a second diagnosis when your cardiologist sees a patient who endured an MI in the past - whether three months or three years ago. "I use 412 as a supporting diagnosis when there is an old diagnosed MI without patient symptoms," Anderson says.

Fifth Digits Reflect Episodes of Care

Remember, you must also use a fifth digit with 410. This can be confusing, but you'll find valuable advice below.
"1" is immediate: Choose 1 (Initial episode of care) for the period of care immediately following an MI until the patient is discharged, no matter where the cardiologist provides the care.
Example 1: "If the patient presents with symptoms, positive test results, and no previous history of an infarction, but the cardiologist doesn't document the site, then I use 410.91," Anderson says. "I use '1' when the documentation shows that the MI occurred within eight weeks or less."
Example 2: If the patient is admitted to a hospital with an MI, then moved to another location for treatment, you should still use 1 as the fifth digit, regardless of the amount of time spent at each facility. "You would treat this as a newly diagnosed MI and code accordingly - basically because the patient was not discharged to go home, meaning this is the same episode of care," Emerick says.
When care is subsequent, choose "2": Use 2 (Subsequent episode of care) when the patient is "admitted for further observation, evaluation or treatment for a myocardial infarction that has received initial treatment but is still less than eight weeks old," ICD-9 says.
Example 1: A patient who went home after having an MI six weeks ago comes back to the hospital for a cardiac catheterization. The eight-week window is still open, but the initial episode of care ended with the patient's discharge. So you should use 2 as the fifth digit.
Example 2: A patient presents to the cardiologist's office six weeks after discharge of a previous MI. The cardiologist performs an EKG, which shows only the previously diagnosed anterior wall infarction. "You should use 410.12 (Acute myocardial infarction; of other anterior wall, subsequent episode of care)," Anderson says.
Note: Once the infarction is more than eight weeks old, you should use 414.8, Anderson adds. This diagnosis code's descriptor specifically states "any condition classifiable to 410 specified as chronic or presenting with symptoms after eight weeks from date of infarction."
Not enough info? Fall back on "0": Use 0 (Episode of care unspecified) when you do not have enough information to assign 1 or 2. You should use this digit rarely, because it's important to code to the greatest specificity possible, and you should be able to locate information on when the MI occurred in most cases. "I have never used the fifth digit '0,' " Anderson says.
Use what you've learned: Putting all five digits together, you would use 410.31 (Acute myocardial infarction; of inferoposterior wall; initial episode of care) for an encounter with a patient who had an MI of the inferoposterior wall three weeks ago and has not been discharged from care. But if the same patient is discharged and then returns for observation or a procedure, you would code the visit as 410.32.

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