Are There ICD-10-CM or CPT® Coding Implications to Clarify Fourth Universal Definition of AMI?

The new definition includes clinical concepts that were not an option before when choosing an MI diagnosis.

Since 2012, changes and updates have continued to clarify the acute myocardial infarction (AMI) diagnosis. There are now five types of MI diagnoses that have been expanded and updated through the years, and this year, we have a few new and updated concepts, titled “The Fourth Universal Definition of AMI.”

As. Dr. Hu’s September ICD10monitor article stated, “like the third universal definition did for the second, the fourth universal definition adds clarity on how newer and more sensitive tests, such as high-sensitivity cardiac troponin (hs-cTn) and late gadolinium enhanced cardiac magnetic resonance (LGE-CMR), fit into the classification scheme first introduced in 2007. If you haven’t learned the classification system yet, it’s about time you did, as it ain’t going anywhere.”

What’s New?

There are new clinical concepts that were not an option before when choosing an MI diagnosis:

• The differentiation of myocardial infarction from myocardial injury;
• The use of CV magnetic resonance to define etiology of myocardial injury;
• The use of computed tomographic coronary angiography in suspected MI;
• The highlighting of peri-procedural myocardial injury after cardiac and non-cardiac procedures, as discrete from myocardial infarction; and
• The consideration of “electrical remodeling,” a.k.a. cardiac memory, in assessing repolarization abnormalities with tachyarrhythmia, pacing, and rate-related conduction disturbances.

The updated clinical concepts include the following:

• Type 1 MI: Emphasis on the causal relationship of plaque disruption with coronary athero-thrombosis (heart not getting enough oxygen, acute MI, I21.-)
• Type 2 MI: Setting with oxygen demand and supply imbalance, unrelated to acute coronary athero-thrombosis
• Type 2 MI: Relevance of presence or absence of CAD to prognosis and therapy

With other types 3, 4a, and 5 relating to interventions and procedures, the concepts were more detailed, but the concepts themselves unchanged.

The ICD-10-CM 2019 Official Guidelines for Coding and Reporting also added direction for reporting subsequent MI, which comes on the heels of details regarding the upcoming release of the Fourth Edition of the Universal Definition of MI, as published in the American Journal of Medicine.

• Under Section I.C.9.e.4, the Guidelines now state that if a subsequent MI of one type occurs within four weeks of an MI of a different type, assign the appropriate codes from category I21.- (acute myocardial infarction) to identify each type. In this instance, coders should not assign a code from category I22.- (subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction). Codes from category I22.- should only be assigned if both the initial and subsequent MIs are Type 1 or unspecified.

Now, as I have been reading through many of these physician articles about this new universal definition of AMI, I began to question the impact it could have on the CPT® coding intent for interventional procedures (PCI) for acute MI diagnoses.

I noticed that each narrative physician note, devotes significant attention to certain common clinical situations in which the diagnosis of MI may be particularly difficult. For example, patients with chronic renal failure are known to often have chronically elevated cTn (troponin) levels.

The new definition is still applicable to these patients, as a rise and/or fall in troponin, together with clinical evidence of myocardial ischemia, should still be used to diagnose an MI for this patient population.

But when this type of AMI, which is similar to what is seen in procedure note documentation for a percutaneous intervention (PCI) presentation, is present, is this still considered “during” an AMI for the purpose of performing the percutaneous coronary intervention with CPT could code 92941? Or is this what is commonly referred to as ACS, or acute coronary syndrome where PCI for this diagnosis would be captured with 92920-92928?

The reason I question this, is that the CPT code for PCI performed “during” an acute myocardial infarction is associated with some controversy. Many coders, again, tend to routinely report the 92941 (Percutaneous transluminal revascularization of acute total/subtotal occlusion during acute myocardial infarction, coronary artery, or coronary artery bypass graft, any combination of intracoronary stent, atherectomy, angioplasty, including aspiration thrombectomy when performed, single vessel) when the generic diagnosis of AMI is listed in the header of a procedure report without reviewing the report detail for specifics regarding STEMI vs nonSTEMI AMI and the realities of the patient presentation at the time of the PCI encounter.

When I review such procedure reports, there is evidence of “elevated cTn levels” or “high troponin levels noted” in the documentation for a non-STEMI MI. However, there is often not an emergent need for the PCI, only a planned procedure, or there is evidence of a non-ST elevation myocardial infarction, without current, ongoing symptoms prompting, again, emergent activation of the catheterization laboratory with demonstration of a subtotal or total coronary occlusion of the culprit vessel.

Furthermore, coding guidance in the CPT Assistant, January 2014, Volume 24, Issue 1 states:

“For the purposes of PCI coding, the designation ‘during acute myocardial infarction’ refers to a procedure that meets all three of the following requirements:

1. Electrocardiographic changes consistent with acute myocardial infarction are recognized, for example, any of the following:

• ST elevation not attributable to a bundle branch block or pericarditis
• New or undetermined left bundle branchblock
• New or evolving Q waves
• Persistent horizontal ST depressions in the anterior leads consistent with posterior ST elevation
• Ongoing ventricular tachycardia, ventricular fibrillation, pulseless electrical activity, or asystole in a clinical scenario consistent with acute myocardial infarction
• The patient has ongoing symptoms suggestive of acute myocardial infarction despite nonspecific electrocardiography (EKG) changes

2. Emergent coronary angiography and PCI are performed. For example, once the diagnosis of acute myocardial infarction is recognized, the patient is brought urgently to the laboratory for treatment during the normal daytime schedule for the catheterization laboratory, or during off-hours, the catheterization laboratory is activated to treat the patient urgently.
3. PCI is performed on a target lesion that is totally (100 percent) thrombolysis in myocardial infarction (TIMI), grade flow of zero, or sub-totally occluded.”

If the patient has a myocardial infarction, is stabilized, and goes to the catheterization lab electively a day or two later, this would not meet the requirements for a procedure performed during an acute myocardial infarction, per CPT Assistant, again when discussing appropriate coding.

So clinically, this new or better clarified type 4 AMI, is good news as it pertains to options for physicians looking to make sure their MI diagnosing is accurate.

But from a coding perspective, I would use caution when coding for the PCI for AMI, with the CPT code 92941 unless the documentation is very clear that there is clinical evidence that the infarction is actively occurring during the intervention.

Program Note:

Listen to Terry Fletcher report on this topic today on Talk Ten Tuesdays, 10 a.m. EST.

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