Taking the Mystery out of Type 2 Myocardial Infarction

By Andrew Maigur, MD, system director, Physician Advisor Program

Dear colleagues and friends,

The 2018 American College of Cardiology guidelines on the universal definition of myocardial infarction (MI) drastically changed our understanding of MI, moving from a definition based on ST segment changes on an electrocardiogram (EKG) to one based on pathophysiology. Here is my attempt to make it simpler:

Definition: an elevated high sensitivity troponin, with a significant rise or fall (delta of 20 percent or 3ng/L), plus supply and demand mismatch etiology, plus one or more of the following:

• Symptoms of myocardial ischemia, such as chest pain or angina equivalents
• New ischemic EKG changes (unusual in Type 2 MI)
• Imaging evidence, such as wall motion abnormalities on echocardiogram, etc.
• Identification of intracoronary thrombosis (unusual in Type 2 MI)

In the case of an asymptomatic Type 2 MI (elderly patients, those with diabetes, women, etc.), the documentation must be explicit.

Common supply demand mismatch etiologies include:

• Non-coronary:
  • Severe hypoxic respiratory failure
  • Severe anemia
  • Hypotension/shock including septic shock
  • Severe tachy/brady arrhythmias
  • Hypertensive crisis +- left ventricular hypertrophy (LVH)
• Coronary:
  • Coronary artery vasospasm
  • Coronary embolism
  • Coronary dissection
  • Fixed coronary artery disease (usually in the setting of non-coronary etiology)

So, what difference does this make to the clinician? I’m glad you asked.

We now have an International Classification of Diseases (ICD) 10 code 121.A1 for Type 2 MI to reflect sicker patients with increased short- and long-term mortality. Treat the underlying cause, and pursue further cardiac evaluation based off of risk stratification with an inpatient or outpatient cardiac evaluation. Type 2 MI is an exclusion criteria for acute myocardial infarction (AMI) core measures; is a major co-morbidity/complication (MCC); and impacts length of stay (LOS), severity of illness (SOI) scores, risk of mortality (ROM) scores, and case mix index (CMI). This diagnosis is particularly prone to payor denials, hence the importance of documenting clinical indicators that support the diagnosis along with the specific etiology for supply demand mismatch.

When ordering high sensitivity troponin, consider whether you are ruling in or ruling out a Type 1 MI or Type 2 MI. With the first elevated troponin, you can make an uncertain diagnosis, analyze the trend for a delta greater than 20 percent, and link supply demand mismatch with the underlying etiology.

My philosophy as a hospitalist/physician advisor is to take excellent care of patients and document well to get credit for having done so. We want the patient to look as sick and complex in the medical record as they appear in real life. Happy Documentation.

Back to the August 2019 issue of Premier Pulse