Anesthesia Coding Alert

Also: Watch for notes about associated organ involvement.

AHypertension can increase the level of your anesthesia provider’s work during surgery. Add that to the fact that nearly one in three U.S. adults has been diagnosed with hypertension, and you’ll see why knowing how to select the correct diagnosis can help your claims.  Fortunately, if you’ve taken time to master the rules of ICD-9 coding, you should find the transition to ICD-10 a smooth one. 

ICD-9 codes: Most hypertension is considered primary or essential hypertension, and in ICD-9, it’s coded with a 401.x (Essential hypertension) category code. To code for primary hypertension in ICD-9, you first need to determine whether the hypertension is malignant, benign, or unspecified. The fourth digit for 401.x codes indicates whether the hypertension is malignant, benign, or unspecified:

• 401.0, Essential hypertension, malignant
• 401.1, Essential hypertension, benign
• 401.9, Essential hypertension, unspecified.

ICD-10 simplification: In ICD-10, you’ll no longer need to specify whether primary hypertension is malignant, benign, or unspecified. As a result, the hypertension table, found in the Alphabetic Index in ICD-9-CM, isn’t included in ICD-10. You’ll report all primary hypertension with the same code: I10 (Essential [primary] hypertension).

This change will be a positive one for coders whose providers fail to specify malignant or benign in their documentation, leaving them to report the unspecified code under ICD-9.

Remember to Watch for Organ Involvement

You also can categorize primary hypertension according to end organ involvement. When hypertension causes heart disease, chronic kidney disease, or both heart and chronic kidney disease, both ICD-9 and ICD-10 refer you to separate code categories. 

Example: When you select a diagnosis code for a patient diagnosed with hypertensive heart disease in ICD-9, you look to the 402.xx (Hypertensive heart disease) category. These codes are further specified with a fourth digit to indicate whether the hypertension is malignant, benign, or unspecified, and a fifth digit that indicates whether the patient also has a heart failure diagnosis.

In ICD-10, your code selection for patients with hypertensive heart disease is streamlined. You have two codes from which to choose:

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

Additional code: For those patients who have a diagnosis that includes heart failure, ICD-9 and ICD-10 ask you to also list a code to specify the type of heart failure. In ICD-9, look to the 428.0-428.43 range. For ICD-10, you’ll need to list a code from the I50.- (Heart failure) category.

Caution: One thing that’s a little confusing about the hypertensive heart disease ICD-10 codes is that “0” in the fifth digit on the ICD-9 code means that the patient does not have heart failure. But in ICD-10 the “0” on the end of the code means the patient does have heart failure.

Cause matters, too: You must have documentation to support a causal relationship between the patient’s hypertension and his heart disease to list a 402.xx or I11.- code. If there is no documentation that the two conditions are linked, you must report them separately. The relationship, documented by the physician, may be implied (such as “hypertensive heart disease”) or stated (“heart failure due to hypertension”).