Cardiology Coding Alert

Just because hypertension (401-405) is a common diagnosis for cardiology practices doesnt mean its always coded correctly, experts warn. Complicating the matter is the confusion surrounding the definitions of malignant and benign. Finally, some hypertensive conditions shouldnt be coded in this series at all. Accordingly, the key to reducing denials and increasing reimbursement is to understand the various types of hypertension and to code each one correctly.

Tip: Most coders refer to the hypertension table in the alphabetic index in the ICD-9-CM manual. Although thats a good place to start, remember to verify hypertension codes in the tabular index for fourth and fifth digit specificityor your claim could be denied.

1. Essential hypertension (401). Whatever you do, do not bill for this truncated code because it will automatically result in a denial. (Medicare notes its one of the top five diagnostic codes most denied for lack of specificity.)

In fact, out of all codes in this series (401-405), about 80 percent are either nonspecific or require an additional digit. For example, all codes require at least a fourth digit to specify whether the condition is malignant or benign, while those in 403 (hypertensive renal disease) and 404 (hypertensive heart and renal disease) also require a fifth digit subclassification to indicate whether the hypertension is associated with organ failure.

2. Essential hypertension (401.0 to 401.9). Selecting the right code in this category depends on a clear understanding of the definition of essential hypertension, as well as distinguishing among malignant, benign and unspecified classifications of the disease process.

In about 90 percent of cases, the specific cause for the hypertension cannot be determined, so the term essential is used, explains Brendan Phibbs, MD, chief of cardiology at Kino Community Hospital in Tucson, AZ, and author of The Human Heart: A Basic Guide to Heart Disease. Essential hypertension is associated with certain risk factors, such as family history, race, stress, obesity, poor diet, and lack of exercise, he says.

However, just because the cause of the hypertension cannot be determined does not mean an appropriate diagnostic code cannot be allocated, stresses Nancy Reading, RN, BS, CPC, principal of Reading Reimbursement Consultants, a multi-specialty coding and reimbursement consulting firm in Salt Lake City, UT.

One of the biggest problems I see with diagnostic coding in cardiology practices is that 401.9 (unspecified hypertension) has been listed on the superbill as a convenience and, over time, has inadvertently become a dump code for all hypertension, she says.

Such dump coding can directly affect reimbursement. For instance, if you code 401.9 (unspecified) and the patient is admitted to the hospital, the cardiologists portion of the hospital charges may be denied.

Instead of automatically coding 401.9, physicians should differentiate the type of hypertension treated and document accordingly. Coders can then choose appropriately between the terms malignant and benign.

Note: Unlike the coding conventions in the neoplasm section of the ICD-9-CM manual, these two words (malignant and benign) dont refer to the presence or absence of cancer, but rather the severity of the condition as determined by blood pressure readings and other factors.

Benign hypertension. The most common type of essential hypertension, benign hypertension, develops slowly over an extended time. It is usually asymptomatic. Class I is a mild form in which the diastolic pressure is 90 to 104; class II is considered medium, with a diastolic pressure of 105 to 119.

Malignant hypertension. This form of hypertension is defined in diagnostic manuals as severe high arterial blood pressure without apparent organic cause. Medicodes ICD-9 manual further defines the condition as a severe form of hypertension, wherein the patients blood pressure reading is consistently higher than 120 diastolic and is difficult to treat. No single blood pressure level consistently produces malignant hypertension for all patients. Because a patient can have a blood pressure over 120 and not have notable organ damage, using blood pressure numbers alone to determine malignancy is inappropriate.

Note: Jo Ann Steigerwald, ART, CPC, practice Management Consultant for the State Medical Society of Wisconsin, points out that part of the coding confusion is due to the fact that the World Health Organization (WHO)the group which wrote and maintains the ICD-9 systemuses a different definition for malignant and benign hypertension than our U.S. doctors do. The definition in Medicodes coding book is pretty close to the WHO definition; the other coding books definitions are more specific to the United States, she says.

For example, Phibbs uses the following scenario to illustrate malignant hypertension:

A patient between the age of 30 and 60 presents with headache, blurred vision, shortness of breath, or chest pain. The diastolic pressure is over 110. The blood vessels of both retinas show severe disease with hemorrhages, as well as papilledema (bulging of optic nerve into the eye).

This is the picture of accelerated or malignant hypertension, he says. Its easy to recognize and its a real emergency. Patients with these findings should be hospitalized and treated vigorously.

Therefore, prognosis is another distinguishing factor between malignant and benign hypertension. Even with the best treatments, 30 percent of patients with malignant hypertension will die in one to three years and 50 percent will die in five years, Phibbs explains.

3. Hypertensive heart disease, hypertensive renal disease, and hypertensive heart and renal disease (402, 403, and 404). Essential hypertension that is not controlled can also affect the heart, kidneys, or both. So you need to code accordingly.

Phibbs explains: When the blood continues to exert too much pressure against the walls of the arteries, the blood vessels will eventually be damaged and the blood flow reduced. If this continues, not only will heart and kidney damage occur, but as the heart is forced to work harder, the left ventricle enlarges. Eventually, both the left and right ventricles may fail and fluid may build up in the lungs, causing congestive heart failure.

402: When hypertension causes heart malfunctions, such as cardiomegaly, cardiopathy, and cardiovascular disease, use a code from the 402 range (hypertensive heart disease). As with code 401, youll need a fourth digit to distinguish between malignant, benign, and unspecified, but youll also need a fifth digit to indicate whether congestive heart failure accompanies the hypertension.

403: When hypertension causes renal disease such as arteriolar nephritis, arteriosclerosis of the kidney or renal arterioles, use a code from the 403 range (hypertensive renal disease). Use a fourth digit to indicate whether the hypertension is malignant or benign. Use a fifth digit of 0 if the documentation does not mention renal failure; use 1 if it does.

404: When hypertension causes both heart and renal disease, use a code from the 404 range (hypertensive heart and renal disease). Use a fourth digit to indicate whether the hypertension is malignant or benign. Use a fifth digit of 0 if the documentation does not mention either congestive heart failure or renal failure; use 1 if it mentions congestive heart failure; use 2 if it mentions renal failure; use 3 if it mentions both congestive heart failure and renal failure.

4. Secondary hypertension (405). The codes in this range indicate high blood pressure that is caused by an underlying disease or condition. In the earlier codes
(401-403), hypertension causes the problem and affects a target organ, Reading explains. But with this category, the diseased organ is causing the problem.

Take renovascular hypertension, for example. If a patients renal artery has hardened, the kidney tissue doesnt get enough blood, then a large amount of a chemical called renin is released into the circulation, Phibbs explains. Renin breaks down into angiotensins, which causes the blood pressure to rise. A PTCA can relieve a hardened renal artery, he notes.

As with other codes in the hypertension section, youll need to indicate whether the secondary hypertension is malignant, benign or unspecified. But codes in the 405 range do not need a fifth digit (which indicates organ failure).

Note: Do not use a code from the hypertensive series if a patient with no history of hypertension exhibits an elevated blood pressure. Instead, use symptom code 796.2, (elevated high blood pressure without diagnosis of hypertension) sometimes known as the white-coat syndrome. It may be that he or she is under an extreme amount of stress, just experienced a minor accident, or has a fear of the physician.