By Judy Monestime bio
Chapter 9 of ICD-10 CM ranges from I00 to I99. This chapter contains an expanded number of specific codes that describe coronary, cerebral, and vascular diseases. “Use additional code to identify” notes appear throughout the chapter to direct the coder to identify exposure to, history of current use of, and dependence on tobacco. Codes also specify the laterality of vessels to identify the specific location of disease, for example, left middle cerebral artery. The chapter includes the following blocks:
I00-I02 Acute rheumatic fever
I05-I02 Chronic rheumatic heart diseases
I10-I15 Hypertensive diseases
I20-I25 Ischemic heart diseases
I26-I28 Pulmonary heart disease and diseases of pulmonary circulation
I30-I52 Other forms of heart disease
I60-I69 Cerebrovascular disease
I70-I79 Diseases of arteries, arterioles and capillaries
I80-I89 Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified
I95-I99 Other unspecified disorders of the circulatory system
The terminology used to describe several cardiovascular conditions has been revised to reflect more current medical practice. For example, acute myocardial infarction is now identified as ST elevation myocardial infarction (STEMI) and non-ST myocardial infarction elevation (NSTEMI).
The ICD-10-CM Official Guidelines for Coding and Reporting state:
The ICD-10-CM codes for acute myocardial infarction (AMI) identify the site, such as anterolateral wall or true posterior wall. Subcategories I21.0-I21.2 and code I21.3 are used for ST elevation myocardial infarction (STEMI). Code I21.4, Non-ST elevation (NSTEMI) myocardial infarction, is used for non ST elevation myocardial infarction (NSTEMI) and nontransmural MIs:
If NSTEMI evolves to STEMI, assign the STEMI code. If STEMI converts to NSTEMI due to thrombolytic therapy, it is still coded as STEMI.:
For encounters occurring while the myocardial infarction is equal to, or less than, four weeks old, including transfers to another acute setting or a postacute setting, and the patient requires continued care for the myocardial infarction, codes from category I21 may continue to be reported. For encounters after the four-week time frame and the patient is still receiving care related to the myocardial infarction, the appropriate aftercare code should be assigned, rather than a code from category I21. For old or healed myocardial infarctions not requiring further care, code I25.2, Old myocardial infarction, may be assigned.:
A code from category I22, Subsequent ST elevation (STEMI) and non ST elevation (NSTEMI) myocardial infarction, is to be used when a patient who has suffered an AMI has a new AMI within the four-week time frame of the initial AMI. A code from category I22 must be used in conjunction with a code from category I21. The sequencing of the I22 and I21 codes depends on the circumstances of the encounter.:
Let’s practice! How do you code the following?:
A 65-year-old patient is admitted six weeks post-acute anterolateral myocardial infarction with a subsequent posterior acute MI. Which is the appropriate coding and sequencing for the encounter for the posterior acute MI in ICD-10-CM?
I21.29 STEMI of other sites
I25.2 Old Myocardial Infarction
Rationale: ICD-10-CM has two categories for acute myocardial infarction: I21, Acute myocardial infarction, and I22, Subsequent acute myocardial infarction. Category I21 is for all cases of initial myocardial infarction and is to be used from onset of the AMI until four weeks following onset. A code from I22 is to be used if a patient who has suffered an AMI has a new AMI within the four-week time frame of the initial AMI. A code from category I22 must be used in conjunction with a code from category I21 (ICD-10-CM Coding Guideline I.C.9.e.4).
Judy Monestime, MBA, CDIP, CPC, is an AHIMA-approved ICD-10-CM/PCS trainer.
