If you understand the FY 2021 ICD-10-CM coding guidelines involving causal relationships and the word “with” in the Alphabetic Index of the ICD-10-CM coding manual, coding for hypertension and heart disease in ICD-10-CM should not be difficult.

stethoscope with sphygmomanometer used to diagnose hypertensive heart failure

Question:  Patient has congestive heart failure due to hypertension. Assign the ICD-10-CM code(s).


I11.0, I50.9

Hypertension is another term for high blood pressure and means the pressure inside the blood vessels is too high. The heart must work harder to pump against this pressure, and eventually it leads to thickening of the heart muscle, according to medlineplus.gov. Over time, this thickening can result in a lack of oxygen and result in weakening of the heart and even heart failure.

According to the 2021 ICD-10-CM Coding Guidelines, the coder may assume a causal relationship between hypertension and heart disease, because the two conditions are linked by the term “with” in the Alphabetic Index. Even if the documentation does not specifically state that the two conditions are related, we can and should code them as related…

Unless the documentation specifically states the conditions are not related.

For hypertension and conditions not specifically linked by relational terms such as “with,” “associated with” or “due to” in the classification, provider documentation must link the conditions in order to code them as related.

Locate and Verify

When looking up Hypertension in the Alphabetic Index, see Hypertension, heart, with heart failure (congestive) I11.0. In the Tabular, we can verify the correct code as:

I11.0, Hypertensive heart disease with heart failure

Note: There are only two codes listed under category I11, Hypertensive heart disease:

  • I11.0, Hypertensive heart disease with heart failure
  • I11.9, Hypertensive heart disease without heart failure

Another synonym listed under I11.0, Hypertensive heart disease with heart failure, is Hypertensive heart failure.

There is a note under I11.0 that states “Use additional code to identify type of heart failure (I50.-).”

When we go to I50.- in the Tabular, we see that the codes listed under category I50, Heart failure, are:

  • I50.1, Left ventricular failure, unspecified
  • I50.20‑I50.23   I50.2, Systolic (congestive) heart failure
  • I50.30‑I50.33   I50.3, Diastolic (congestive) heart failure
  • I50.40‑I50.43   I50.4, Combined systolic (congestive) and diastolic (congestive) heart failure
  • I50.810‑I50.89   I50.8, Other heart failure
  • I50.9, Heart failure, unspecified

The documentation in this coding scenario indicates the patient has congestive heart failure. When we go to I50.- in the Tabular, we can see that the code for congestive heart failure is:

I50.9, Heart failure, unspecified

Other synonyms listed under I50.9, Heart failure, unspecified, include:

  • Cardiac, heart or myocardial failure NOS
  • Congestive heart disease
  • Congestive heart failure NOS

According to the “Code First” note at I50, heart failure due to hypertension (I11.0) should be sequenced before I50.9 for congestive heart failure.

Be sure to see the information above I10 that indicates for Hypertensive Diseases (I10-I16), we are to assign an additional code to identify tobacco use or dependence, exposure to, history of, or occupational exposure to tobacco. We cannot code for it here, however, because it wasn’t documented.

There are also Includes, Excludes1, and Excludes2 notes that need to be reviewed and assigned, as applicable.

This post has been reviewed and updated to reflect the FY 2021 ICD-10-CM coding guidelines.