Updated on: November 28, 2016

Putting a Halt to ICD-10 AMI Documentation Obstacles

Original story posted on: February 8, 2016

ICD-10 went into effect Oct. 1, 2015 and, so far, everything seems to be going pretty well. There are a few areas, however, that continue to give clinical documentation improvement (CDI) specialists and coders headaches. One of these problems is Acute Myocardial Infarction (AMI) documentation. In ICD-10 there is a demand for increased specificity – most of the documentation problems surrounding AMI revolve around documentation of the AMI site, timing of the event, and the type of AMI.

Though overall morbidity and mortality rates of AMI have been slowly improving, it continues to be a leading cause of death worldwide. Regarding the prognosis of those that survive an AMI, “Survivors of a first acute myocardial infarction (MI) face a substantial risk of further cardiovascular events, including death, recurrent MI, heart failure, arrhythmias, angina, and stroke.”* Now with the increased specificity required in ICD-10 it is more important than ever to get documentation and coding of AMI right. This article will hopefully help dispel some of the confusion.

AMI Site and Artery Involved – Location, Location, Location

Let’s tackle the first problem of documentation of the AMI site. You know what they say – LOCATION, LOCATION, LOCATION. Many physicians believe that, because they have documented the AMI in the progress notes, H&P, and/or discharge summary, that this is “enough.” Or that because they documented the AMI and performed a cardiac catheterization and placed a stent in the left anterior descending (LAD) that we (CDI and coders) know and can code that LAD AMI site. 

But they would be wrong. So as a CDI or coder, if the physician is documenting MI or AMI without specification of the site in the notes, we must query for the site. Suggestions for site of the AMI include:

  • Anterior
  • Apical-Lateral
  • Basal-Lateral
  • Inferior
  • Inferoposterior
  • Lateral
  • Posterior
  • Septal

Suggestions for artery involvement include: 

  • Left main coronary artery (LM)
  • Left anterior descending artery (LAD)
  • Circumflex coronary artery (CIRC or CIRX)
  • Other coronary artery of anterior or inferior wall

If the patient had a cardiac catheterization, be sure to add that information to your query. Adding this information will allow them to better connect-the-dots via a query response. 

AMI – Timing is Everything

The second biggest issue when it comes to documenting AMI is the timing of the AMI event. In ICD-9-CM an “acute” or “new” AMI was considered to have occurred within the past eight weeks. In ICD-10-CM this time frame has changed to four weeks. If the physician is not documenting when the patient had the MI then a query must be placed. As a CDI you may have to do a little investigative work and see if the patient has been in the hospital in the last 4 weeks either as an outpatient or an inpatient. If the patient has not been in your hospital in the last 4 weeks further investigation may be needed to ensure there wasn’t a previous insult that was treated at another facility. If there is information in the documentation to suggest the patient may have had an initial injury within 4 weeks of this encounter the physician will still have to be queried to validate this information. ** 

The Centers for Medicare & Medicaid Services (CMS) have changed the definition of AMI to the following: “Timeframe – An AMI is now considered “acute” for four weeks from the time of the incident.  ICD-10 allows coding of a subsequent MI, a new MI that occurs during the four-week “acute period of the original AMI.” They also go on to say that, “ICD -10 does not capture episode of care (e.g. initial, subsequent, and sequelae).”

Sounds confusing, right? Really what CMS is stating is that Sequelae will not be coded anymore and each new MI needs to be coded individually. This confusion can cause inconsistencies in coding, quality metrics and other types of reporting. So it is very important to get the documentation needed for correct coding of AMI cases. Here is a helpful coding clinic related to this matter: 

AHA Coding Clinic for ICD-10 – 4th Q 2012, pages 102-103

Question: A 66 y/o male was DC’d from the hospital after being hospitalized for a week for treatment of an acute transmural MI of the anterior wall. A week after his discharge he was brought back in the ED for chest pain and was admitted for treatment of a subsequent acute transmural MI of the inferior wall. How should this second admission be coded? 

Answer: The sequencing of the I22 and I21 codes depends on the circumstances of the encounter. Since the reason for the admission was the subsequent MI, assign code I22.1, Subsequent ST elevation (STEMI) myocardial infarction of inferior wall, as principle diagnosis. Assign code I 21.09, ST elevation (STEMI) myocardial infarction involving other coronary artery of anterior wall as a secondary diagnosis. An I21 code must accompany an I22 code to identify the site of the initial acute myocardial infarction (AMI), and to indicate that the patient is still within the 4 week time frame of healing from the initial AMI. 

A few more helpful hints about the timing of AMI: 

  • When in doubt, remember you can’t use the subsequent MI code (I22) alone.
  • If you do end up coding an acute MI as a secondary diagnosis in the above case, it does not “count” as a CC or MCC, nor does it increase SOI/ROM.

AMI – State the Type

The last problem of AMI documentation is the type of AMI. Some physicians document AMI or MI and some document NSTEMI or STEMI.  It is always better to be more specific and document NSTEMI or STEMI than the very generic terms AMI or MI. Types of AMI include:

  • ST elevation (STEMI)
  • Non ST elevation (NSTEMI)
  • Non-Q wave, Nontransmural
  • Q-wave
  • Other, specified 

ICD-10-CM allows the CDIS and the coder to differentiate between STEMI and Non-STEMIs. Only one ICD-10-CM code for Non-STEMI is noted and includes the diagnosis of AMI that is defined as subendocardial or transmural (even if the site is noted). For STEMI it will be imperative to know the wall of the heart affected AND the specific culprit vessel.

(Note: These codes will include subcategories I21.-,)

Per ICD-10-CM Coding Guidelines if a Non-STEMI evolves into a STEMI use the appropriate code for the STEMI for the encounter. However if a STEMI is reversed to a Non-STEMI with the use of thrombolytics the encounter will remain coded as the STEMI.

Lastly, when possible make sure the patient’s history and current tobacco use or dependence is documented. Also ensure that any use of thrombolytics that has occurred within 24 hours of the patient being admitted to your facility is documented.

In closing, remember there are three items of documentation needed to appropriately code an AMI in ICD-10-CM: location, timing of the event and type of MI. Documentation of unspecified MI is still much better documentation than “chest pain.” However, in order to tell the patient’s full (and accurate!) story, we need as many specifics of an AMI as possible. This diagnosis may require queries and generalized MI documentation education to your providers. 

Disclaimer: Every reasonable effort was made to ensure the accuracy of this information at the time it was published. However, due to the nature of industry changes over time we cannot guarantee its validity after the year it was published.
Terry Millerd

Terri Millerd is the CDI manager for Panacea Healthcare Solutions. Terry has more than 20 years of experience in clinical nursing, laboratory and CDI. She is a Registered Nurse, Certified Clinical Documentation Specialist (CCDS) from the Association of Clinical Documentation Improvement Specialists (ACDIS), and a board certified Medical Laboratory Technician by ASCP (American Society of Clinical Pathologists).

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