Cardiology Coding Alert

Hint: Never report I24.8 for demand ischemia.

As you're learning the new 2018 ICD-10 codes for cardiology, you should know that CMS and the National Center for Health Statistics (NCHS) have also released the 2018 ICD-10-CM Official Guidelines for Coding and Reporting. In the Guidelines, you will find further direction for hypertension and myocardial infarction (MI) reporting.

The crux of the matter: The 2018 ICD-10 codes and the Guidelines will go into effect Oct. 1, 2017. Review the following quiz questions and safeguard your cardiology reimbursement.

Guidelines Add New Pulmonary Hypertension Section

Question 1: What are the new ICD-10 2018 codes for pulmonary hypertension, and what do the Guidelines clarify about these codes?

Answer 1: The new ICD-10 2018 pulmonary hypertension codes are:

• I27.20, Pulmonary hypertension, unspecified
• I27.21, Secondary pulmonary arterial hypertension
• I27.22, Pulmonary hypertension due to left heart disease
• I27.23, Pulmonary hypertension due to lung diseases and hypoxia
• I27.24, Chronic thromboembolic pulmonary hypertension
• I27.29, Other secondary pulmonary hypertension.

Expanding I27.2 (Other secondary hypertension) and adding these six new codes was a needed addition, according to Theresa Dix, CCS-P, CPMA, CCC, ICDCT-CM, coder/auditor of East Tennessee Heart Consultants in Knoxville, Tennessee.

Although pulmonary hypertension is a common complicating diagnosis in patients with multiple comorbidities, primary pulmonary hypertension is rare, adds Chris Zimmerer, CPC, CCC, Central Billing Office Coder at LifePoint Health^®  in Georgetown, Kentucky. Therefore, I27.2 is the more commonly used code.

To go along with these new codes, the Guidelines will add a new section about pulmonary hypertension to "Chapter 9: Diseases of the Circulatory System (I00-I99)."

This new pulmonary hypertension section for ICD-10 will be very helpful in coding pulmonary hypertension more specifically, says Carol Hodge, CPC, CCC, CEMC, certified medical coder of St. Joseph's Cardiology in Savannah, Georgia.  

Pulmonary hypertension is classified to category I27- (Other pulmonary heart diseases...), according to the Guidelines.

For pulmonary hypertension that is caused by an underlying condition such as pulmonary emboli or emphysema, you would report the secondary code or I27.2, Hodge says.

"For secondary pulmonary hypertension (I27.1, I27.2-), code also any associated conditions or adverse effects of drugs or toxins," the Guidelines maintain. "The sequencing is based on the reason for the encounter."

Although there has always been an instruction to "code also the associated underlying condition," listing this in the Guidelines reinforces that and instructs that either pulmonary hypertension or the underlying condition may be sequenced first, depending upon the reason for the encounter, according to Zimmerer.

Look to New Code I21.9 For Unspecified AMI

Question 2: What code should I report for an unspecified acute myocardial infarction (AMI)?

Answer 2: The new 2018 ICD-10 code for unspecified AMI is I21.9 (Acute myocardial infarction, unspecified).

Acknowledging this addition, the 2018 Guidelines state, "Code I21.9 (Acute myocardial infarction, unspecified) is the default for unspecified acute myocardial infarction or unspecified type. If only type 1 STEMI or transmural MI without the site is documented, assign code I21.3 (ST elevation [STEMI] myocardial infarction of unspecified site)."

Takeway: Before the addition of I21.9, you would have reported I21.3 as the default for unspecified AMI.

"Breaking out unspecified AMI as a separate code is a move towards the greater specificity that underlies the importance of the change to ICD-10," Zimmerer says.

Providers will need to be as accurate as possible in documenting site and type of MI, whenever possible, to avoid denials or returned claims, Zimmerer adds.

Decipher How to Report Subsequent AMIs

Question 3: If the documentation states that the patient has experienced a subsequent AMI, how should I code this?

Answer 3: If a patient who has experienced a type 1 or unspecified AMI has a new AMI within the 4-week time frame of the initial AMI, you should report a code from category I22- (Subsequent ST elevation [STEMI] and non-ST elevation [NSTEMI] myocardial infarction), according to the Guidelines.

You must report a code from category I22- in conjunction with a code from category I21- (Acute myocardial infarction). The sequencing of the I22- and I21- codes depends upon the circumstances of the encounter, according to the Guidelines.

Caution: You should not report I22- for subsequent AMIs other than type 1 or unspecified.

For subsequent type 2 AMI, you should only report new ICD-10 2018 code I21.A1 (Myocardial infarction type 2). For subsequent type 4 or type 5 AMI, you should report only new ICD-10 2018 code I21.A9 (Other myocardial infarction type).

Reference This New Section For Further MI Clarification

Question 4: Will the 2018 Guidelines add a brand-new section to the MI category?

Answer 4: Yes. The 2018 Guidelines will add the "Other Types of Myocardial Infarction" section, which will further clarifies which codes you should report for different kinds of MI.

Caution: Coders will need to scrutinize the provider documentation even more closely in order to select the correct code given all the new specific choices, Zimmerer says.

Type 1 MI: To report type 1 MI, you should choose a code from the I21.0 (ST elevation [STEMI] myocardial infarction of anterior wall) through the I21.4 (Non-ST elevation [NSTEMI] myocardial infarction) range.

Caution: You should only assign codes I21.01-I21.4 to type 1 MIs, Hodge says.

Type 2 MI and Ischemia-related: You should report I21.A1 for type 2 MI and MI due to demand ischemia or secondary to ischemic balance, with a code for the underlying cause. You should never report I24.8 (Other forms of acute ischemic heart disease) for demand ischemia.

Remember that the sequencing of type 2 AMI or the underlying cause are dependent upon the patient's circumstances of admission.

If the documentation describes the type 2 AMI as NSTEMI or STEMI, you should just report I21.A1.

Other MI type: You should report I21.A9 for AMI types 3, 4a, 4b, 4c, and 5.

Caution: The Guidelines also state that you should follow 'Code also' and 'Code first' notes related to complications and for coding of postprocedural myocardial infarctions during or following cardiac surgery.

Editor's note: "We coders are not physicians and cannot interpret what we think the physician is trying to say in regards to the degree or type of MI," says Christina Neighbors, MA, CPC, CCC, Coding Quality Auditor for Conifer Health Solutions, Coding Quality & Education Department, and member of AAPC's Certified Cardiology Coder steering committee. "It is extremely important to always code what it documented and never assume. Educate your physician on what specificities are needed to code the appropriate, correct diagnosis code(s)."

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