Understanding Why MI is a Pain Point for CDI

Frequently, Type 2 MI is inconsistently documented.

February is American Heart Month, a time to raise awareness of cardiovascular health and a time to shine a light on cardiac issues, especially myocardial infarction (MI).

Unfortunately, every year about 805,000 people in the United States have a heart attack. Basically, someone has a heart attack every 40 seconds.  

One type of MI that you often hear about is Type 2 MI. Clinical documentation improvement (CDI) and coding experts at Innova Revenue Group decided that this would be a perfect time to discuss the associated documentation and coding challenges.

Type 2 MIs are a common pain point for CDI departments. This is due to conflicting or lack of clinical indicators in provider documentation that requires further clarification with a query.

Type 2 MIs are frequently incorrectly diagnosed and inconsistently documented. Per The Fourth Universal Definition of MI, released in 2018 by the Journal of the American College of Cardiology, a Type 2 MI is diagnosed in the presence of elevated troponins, primarily due to a supply/demand imbalance without coronary thrombosis (i.e. not due to CAD and the presence of at least one of the following):

• Symptoms of acute myocardial ischemia;
• New ischemic ECG changes;
• Imagining evidence of new loss of viable myocardium, or new regional wall motion abnormality in a pattern consistent with an ischemic etiology; and
• Development of pathological Q waves (usually only when due to coronary embolism or dissection).

A Type 2 MI results from an imbalance between myocardial oxygen supply and demand, unrelated to acute coronary artery thrombosis or plaque rupture. A Type 2 MI is a relative (as opposed to an absolute) deficiency in coronary artery blood flow, triggered by an abrupt increase in myocardial oxygen demand, a drop in myocardial blood supply, or both. In a Type 2 MI, myocardial injury occurs secondary to an underlying process and therefore requires correct documentation of the underlying cause as well.

Common examples of underlying causes of Type 2 MI include acute blood loss anemia (e.g. a GI bleed), acute hypoxia (e.g. COPD exacerbation), shock states (cardiogenic, hypovolemic, hemorrhagic, or septic), coronary vasospasm (e.g. spontaneous), and bradyarrhythmia. Patients with Type 2 MI often have a history of fixed obstructive coronary disease, which when coupled with the acute trigger facilitates the Type 2 MI; however, underlying CAD is not always present.

Type 2 non-ST elevation myocardial infarction (NSTEMI) is also a problematic term for coders. According to coding guidelines, when Type 2 NSTEMI is documented, the code for Type 2 MI should be assigned and the code for NSTEMI should be withheld. If a coder incorrectly assigns the code for a NSTEMI – I21.4 – the case will be inappropriately pulled into the National Cardiovascular Data Registry and included in the Centers for Medicare & Medicaid Services (CMS) cohort for 30-day readmission rates and 30-day mortality rates.

As you can see, getting the provider to properly diagnose a Type 2 MI is extremely important. The one thing to keep in mind is that in a Type 2 MI, there is always demand ischemia. If you see the provider documenting a Type 2 MI without demand ischemia, a query should be issued to validate clinically the diagnosis. If there is no ischemia, another possible diagnosis is myocardial injury. This diagnosis was introduced in The Fourth Universal Definition of MI, which is defined by at least one cardiac troponin concentration above the 99th percentile URL. In 2022, a new code, I5A (Non-ischemic myocardial injury (non-traumatic)) was introduced into the ICD-10-CM classification system. Similar to coding a Type 2 MI, myocardial injury requires the underlying cause to be sequenced first.

It is crucial for clinical documentation integrity specialists (CDISs) to educate providers on Type 2 MIs and the importance of documenting the underlying cause. This will reduce the number of queries sent and get claims out the door quicker!

Programming note: Listen to Lidiya Ter-Markarova report this story live today during Talk Ten Tuesdays with Chuck Buck and Dr. Erica Remer, 10 Eastern.