In this coding spotlight, we will focus on several cardiovascular conditions; codes from Chapter 9 of the 

ICD-10-CM are listed in the table below.


Diseases of the circulatory system

Category codes

Acute rheumatic fever


Chronic rheumatic heart diseases


Hypertensive diseases


Ischemic heart diseases


Pulmonary heart disease and diseases of pulmonary circulation


Other forms of heart disease


Cerebrovascular diseases


Diseases of arteries, arterioles and capillaries


Diseases of veins, lymphatic vessels and lymph nodes, not elsewhere classified


Other and unspecified disorders of the circulatory system




ICD-10-CM classifies hypertension by type as essential or primary (categories I10 to I13) and secondary (category I15).


Categories I10 to I13 classify primary hypertension according to a hierarchy of the disease from its vascular origin (I10) to the involvement of the heart (I11), chronic kidney disease (I12), or heart and chronic kidney disease combined (I13).1


Elevated blood pressure versus hypertension

A diagnosis of elevated blood pressure reading, without a diagnosis of hypertension, is assigned code R03.0. This code is never assigned on the basis of a blood pressure reading documented in the medical record; the physician must have specifically documented a diagnosis of elevated blood pressure.


The postoperative hypertension is classified as a complication of surgery, and code I97.3, postprocedural hypertension, is assigned. When the surgical patient has pre-existing hypertension, only codes from categories I10 to I13 are assigned.


Hypertensive heart disease

ICD-10-CM presumes a causal relationship between hypertension and heart involvement and classifies hypertension and heart conditions to category I11 — hypertensive heart disease — because the two conditions are linked by the term with in the alphabetic index of the ICD-10-CM. These conditions should be coded as related even in the absence of provider documentation linking them. First, code I11.0, hypertensive heart disease with heart failure as instructed by the note at category I50, heart failure. If the provider specifically documents different causes for the hypertension and the heart condition, then the heart condition (I50.-, II51.4-I51.9) and hypertension are coded separately.1

Other heart conditions that have an assumed causal connection to hypertensive heart disease




Myocarditis, unspecified


Myocardial degeneration




Takotsubo syndrome


Other ill-defined heart diseases


Heart disease, unspecified


Hypertension, secondary

Two codes are required: one to identify the underlying etiology and one from category I15 to identify the hypertension. For example:

  • Hypertension due to systemic lupus erythematosus, M32.10 + I15.8.


Hypertensive crisis

A code from category I16, hypertensive crisis, is assigned for any documented hypertensive urgency (I16.0), hypertensive emergency (I16.1), or unspecified hypertensive crisis (I16.9). Report two codes, at a minimum, for hypertensive crisis. The crisis code is reported in addition to the underlying hypertension code (I10-I15).1


Pulmonary hypertension

Pulmonary hypertension is classified to category I27, other pulmonary heart diseases. For secondary pulmonary hypertension (I27.1, I27.2-), any associated conditions or adverse effect of drugs or toxins should be coded.2


Ischemic heart disease

Category I25, chronic ischemic heart disease, includes coronary atherosclerosis, old myocardial infarction, coronary artery dissection, chronic coronary insufficiency, myocardial ischemia, and aneurysm of the heart.


ICD-10-CM has combination codes for atherosclerotic heart disease with angina pectoris. The subcategories for these codes are I25.11, atherosclerotic heart disease with angina pectoris and I25.7, atherosclerosis of coronary artery bypass graft(s) and coronary artery of transplanted heart with angina pectoris.


When using one of these combination codes, it is not necessary to use an additional code for angina pectoris.  A causal relationship can be assumed in a patient with both atherosclerosis and angina pectoris, unless the documentation indicates that angina is due to a condition other than atherosclerosis.2


Heart failure

Systolic heart failure is coded as I50.2 and diastolic heart failure is coded as I50.3-; combined systolic and diastolic heart failure is assigned code I50.4. Fifth characters further specify whether the heart failure is unspecified, acute, chronic or acute on chronic.


Other classifications of heart failure include:

  • Right heart failure, unspecified (I50.810)
  • Acute right heart failure (I50.811)
  • Chronic right heart failure (I50.812)
  • Acute on chronic right heart failure (I50.813)
  • Right heart failure due to left heart failure (I50.814)
  • Biventricular heart failure (I50.82)
  • High output heart failure (I50.83)
  • End-stage heart failure (I50.84)
  • Other heart failure (I50.89)
  • Unspecified (I50.9)


For a diagnosis of left ventricular, biventricular and end-stage heart failure, two codes are required to completely describe the condition: one to report the left, biventricular or end-stage heart failure, and one to identify the type of heart failure.



Cardiomyopathy is coded as I42- with the third character describing:

  • I42.0 Dilated cardiomyopathy, which includes congestive cardiomyopathy
  • I42.1 Obstructive hypertrophic cardiomyopathy, including idiopathic hypertrophic subaortic stenosis
  • I42.2  Other hypertrophic cardiomyopathy, including nonobstructive hypertrophic cardiomyopathy
  • I42.3 Endomyocardial (eosinophilic) disease, including endomyocardial (tropical) fibrosis and Loffler’s endocarditis
  • I42.4 Endocardial fibroelastosis, including congenital cardiomyopathy and elastomyofibrosis
  • I42.5 Other restrictive cardiomyopathy, including constrictive cardiomyopathy not otherwise specified
  • I42.6 Alcoholic cardiomyopathy due to alcohol consumption: a code for alcoholism (F10.-) is also assigned if present
  • I42.7 Cardiomyopathy due to drug and external agent: code first the poisoning due to drug or toxin; if applicable (T36-T65 with fifth or sixth character 1-4 or 6); if the condition is caused by an adverse effect, use an additional code, if applicable, to identify the drug (T35-T50 with fifth or sixth character)
  • I42.8 Other cardiomyopathies
  • I42.9 Unspecified


Two codes may be required for cardiomyopathy due to other underlying conditions; for example, cardiomyopathy due to amyloidosis is coded E85.4, organ-limited amyloidosis, and I43, cardiomyopathy in diseases classified elsewhere. The underlying disease, amyloidosis, is sequenced first.2


Status Z codes

ICD-10-CM provides several Z codes to indicate that the patient has a health status related to the circulatory system, such as the following:

  • Z94.1 Heart transplant status
  • Z95.0 Presence of cardiac pacemaker
  • Z95.1 Presence of aortocoronary bypass graft
  • Z95.810 Presence of automatic (implantable) cardiac defibrillator
  • Z95.811 Presence of heart assist device
  • Z95.828 Presence of other vascular implants and grafts


These codes are assigned only as additional codes and are reportable only when the status affects the patient’s care for a given episode.



1 ICD-10-CM Expert for Physicians. The complete official code set. Optum360, LLC. 2020.

2 ICD-10-CM/PCS Coding. Theory and practice. 2019/2020 Edition. Elsevier



ANV-NU-0135-20 May 2020

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July 2020 Anthem Provider News and Important Updates -- Nevada