Cardiology Coding Alert

Keep these guidelines on assumptions, renal disease, and heart disease handy.

Hypertension (HTN) is on the rise -- perhaps a third of the U.S. population is already affected. That means that if your HTN coding skills aren't top notch, many of your claims are at risk of errors.

To keep your coding compliant, apply these nine rules based on the ICD-9 official guidelines. (You can download the guidelines from www.cdc.gov/nchs/icd/icd9cm_addenda_guidelines.htm. See section I.C.7.a.)

1: ICD-9 Has a Hypertension Table; Use It

Coding HTN diagnoses can be complex, but the Hypertension Table, listed under the ICD-9 index entry "Hypertension," helps simplify your search.

The table shows not just the basic 401.x (Essential hypertension) codes, but also the codes for conditions due to or associated with HTN. Additionally, the table helps clarify when your code options vary for malignant, benign, or unspecified conditions. Once you've found the code in the index, remember to check it in the tabular list.

2: Documentation Determines 401.x 4^th Digit

ICD-9 official guidelines offer a key rule for compliant HTN coding. When reporting codes from 401.x, you must choose a fourth digit to complete the code: "malignant (.0), benign (.1), or unspecified (.9). Do not use either .0 malignant or .1 benign unless medical record documentation supports such a designation."

That guideline means that if the physician documents only "hypertension" as the diagnosis (without stating benign or malignant), your only compliant choice is 401.9 (Essential hypertension; unspecified). Although benign HTN is far more common than malignant HTN, you shouldn't assume any patient's HTN is benign when you choose your code.

Eye on the future: ICD-10 is slated to replace ICD-9 in 2013. The current ICD-10 code set does not distinguish between benign and malignant HTN, so your documentation requirements may ease a bit. For example, I10 (Essential hypertension) applies to both benign and malignant cases.

3: 'Hypertensive' Supports 402.x Use

When a patient has both HTN and heart disease, knowing whether the HTN caused the heart condition is crucial to proper coding.

Look to see whether the patient has a condition described under heart disease codes 425.8, 429.0-429.3, 429.8, and 429.9, official guidelines state. Also check the documentation for a stated or implied causal relationship to HTN (for example, "due to HTN" or "hypertensive heart disease"). You should never assume the HTN caused the heart disease.

"Proof is important," stresses cardiology coding consultant Terry A Fletcher, BS, CPC, CCS-P, CCS, CEMC, CCC, CMSCS, CMC, of Terry Fletcher Consulting, based in Laguna Beach, Calif.

Related: If documentation does show a causal relationship, then you should report a code from 402.x (Hypertensive heart disease). You should add the appropriate code from 428.x (Heart failure) if the patient has heart failure. You may assign more than one 428.x code if more than one applies to the patient's case.

Not related: If there is no documented causal relationship between the HTN and heart disease, then you should code the HTN and heart disease diagnoses separately (and should not use a 402.x code). Sequence the codes based on the reason for the visit, the guidelines state.

Example: Your cardiologist treats a patient with benign hypertensive heart disease with left ventricular failure.

You report 402.11 (Hypertensive heart disease; benign; with heart failure). This code indicates the patient's entire hypertensive status. You also report a code to specify the type of heart failure: 428.1 (Left heart failure).

4: Assume HTN and CKD Are Connected

In direct contrast to the guidelines for coding HTN and heart disease, ICD-9 does presume a causal relationship between HTN and chronic kidney disease (CKD).

Translation: If documentation shows a patient has HTN and a condition that falls under 585.x (Chronic renal failure) or 587 (Renal sclerosis unspecified), then you should report a code from 403.x (Hypertensive renal disease), even if there's no indication one caused the other. You also should report the relevant 585.x code to indicate the CKD stage.

Be on the watch for acute renal failure in the documentation, too, because that merits an additional code when present.

Example: Documentation indicates benign hypertensive renal disease with stage III CKD. You should report 403.11 (Hypertensive kidney disease; benign; with chronic kidney disease) and add 585.3 (Chronic kidney disease, stage III [moderate]) as a secondary code.

5: Unclutter Coding for Hypertensive Heart and CKD

A single code from 404.xx (Hypertensive heart and renal disease) indicates the patient has both hypertensive heart disease and hypertensive CKD. You again should assume a relationship between the HTN and CKD.

Crucial: When the patient has hypertensive heart disease and CKD, you should choose a code from 404.xx. You should not report 402.x (hypertensive heart disease) and 403.x (hypertensive CKD) together.

To fully describe the patient's medical status, pay attention to ICD-9's instructions to report more than the 404.xx code. If the patient has heart failure, you should add one or more codes from 428.x to indicate the type. For instance, you may need more than one code if documentation indicates systolic or diastolic failure as well as congestive heart failure.

You'll also need to add a code from 585.x (Chronic renal failure) to show the CKD stage.

6: Think 2 Codes for Head Diagnoses

Not all hypertensive diseases have combination codes that instruct you to keep a separate HTN code off your claim.

When the patient is diagnosed with hypertensive cerebrovascular disease, you should report the appropriate code from 430-438.x (Cerebrovascular disease) first, and then report the correct hypertension code, 401.x-405.x.

Similarly, for hypertensive retinopathy, guidelines instruct you first to report 362.11 (Hypertensive retinopathy) and then the appropriate HTN code from 401.x-405.x.

7: 405.x Applies When There's Another Cause

In some cases, an underlying condition can be the cause of the patient's HTN. When documentation reveals that situation, the HTN is known as secondary HTN.

To report this patient's diagnoses, you'll need one code to report the underlying condition (etiology) and a code from 405.x (Secondary hypertension) to report the HTN. Your sequencing will depend on the reason for the admission or encounter, the guidelines state.

Example: Suppose a patient has primary aldosteronism that is causing benign hypertension. You're coding an encounter related to the HTN. You should report 405.19 (Secondary hypertension; benign; other) and 255.10 (Hyperaldosteronism, unspecified).

8: Understand the Meaning of 'Uncontrolled'

Providers may document HTN using the terms controlled and uncontrolled. Controlled usually means the therapy being used is keeping the patient's HTN under control. Uncontrolled may mean either the HTN is untreated or that the current regimen isn't keeping the HTN under control.

In either case, you should choose the appropriate code from 401.x-405.x (Hypertensive disease) to provide the appropriate hypertension codes. You should not assume that either term indicates benign or malignant HTN.

Documentation tip: The term uncontrolled may not affect your code choice, but many local coverage determinations (LCDs) include uncontrolled hypertension as one of the indications required for coverage, says Fletcher.

Renal angiography LCDs offer a good example, she adds. For instance, Pinnacle Business Solutions lists "UNCONTROLLED hypertension with a systolic blood pressure greater than or equal to 160 mmHg or a diastolic blood pressure greater than or equal to 100 mmHg on at least two anti-hypertensive drugs" as one of the indications for coverage in LCD L19658, "Diagnostic Abdominal Aortography and Renal Angiography."

9: Elevated or Transient Doesn't Equal HTN

If documentation shows only elevated blood pressure, you should not use a code from 401.xx.

What to do: Code 796.2 (Elevated blood-pressure reading, without diagnosis of hypertension) is appropriate when documentation doesn't establish HTN definitively.

If the patient is pregnant, look instead to 642.3x (Transient hypertension of pregnancy) for transient HTN of pregnancy, the guidelines state.