Cardiology Coding Alert

If your cardiologist sees a patient with coronary artery disease (CAD) but doesn't identify the location of the disease, you should report 414.00 as the diagnosis, right? Wrong.

Overuse of 414.00 is among the most common coding errors, according to the American Health Information Management Association (AHIMA). Avoid making this mistake by learning the difference between 414.00 and 414.01.

The most prevalent type of heart disease, CAD, occurs when the coronary arteries become narrowed or blocked, says Jerome Williams Jr., MD, FACC, a cardiologist with Mid Carolina Cardiology in Charlotte, N.C. The most common cause is atherosclerosis, a progressive buildup of plaque that allows less blood flow to the heart muscle, resulting in angina pectoris. Some of the many complications of obstructive CAD include angina pectoris, cardiomyopathy or weakened heart muscle, and possibly sudden death.

Guideline: "The rule I have always been told on any type of atherosclerosis is you can only use the code (such as one for CAD) if you have documented a minimum of 30 percent stenosis," says Sandy Fuller, CPC, MCS-P, HIS supervisor and compliance officer at Cardiovascular Associates of East Texas. "If you give a patient with less than 30 percent stenosis the CAD diagnosis, you may cause problems when the patient tries to acquire insurance in the future."

When you code for CAD, you'll look at the subcategory 414.0x. Determine the fifth-digit classification by:

• the location of the disease (for instance, native vessel, bypass graft, etc.)

• whether or not the CAD has occurred in a transplanted heart.

Keep in mind: You may assign more than one code from the subcategory 414.0x. For instance, you might use more than one 414.0x code if the physician indicates that the patient has CAD involving more than one type of coronary artery and specifies which types. In addition, make sure you specify which coronary artery is diseased.

You should only use 414.00 (Coronary atherosclerosis; of unspecified type of vessel, native or graft) if your documentation shows that the patient has obstructive CAD involving coronary artery bypass conduits but the cardiologist didn't specify the location of the obstruction.

Example 1: A patient presents to your cardiologist having had a CABG. The cardiologist documents the patient as having CAD but does not specify if the CAD is of a native vessel or bypass graft.
In this instance, the physician really did fail to specify which type of artery has the CAD when he probably should have. Therefore, if you have documentation that the patient has more than just native arteries, you should use 414.00.

Tactic: To prevent problems like this, you should "try to educate the cardiologist on what the CAD codes mean, as opposed to what the physician documents," Fuller says.

Example 2:- Your cardiologist documents "Patient admitted with CAD and unstable angina" but does not include information about the location. In this situation, you should also code CAD first using 414.00, because this is the reason for the unstable angina (411.1), which you could report as a secondary diagnosis.-

If the cardiologist's documentation tells you that the CAD is of a native coronary artery and the patient is not a heart-transplant patient, you should choose 414.01 (Coronary atherosclerosis; of native coronary artery). You should also report this code in two other circumstances:

• if the patient has CAD and the cardiologist documents that she has no history of a prior CABG, and

• if the patient had a prior percutaneous transluminal coronary angioplasty (PTCA) of a native artery and the cardiologist admits her with reocclusion of this lesion.

Example 1: A CAD patient's medical record clearly indicates that she has had no previous bypass surgery. You should code 414.01.

Example 2: The medical record specifies that the CAD exists in one of the named coronary arteries, such as the left anterior descending, and the patient is not a heart-transplant patient. In this case, you are also safe to use 414.01.

Important: If the documentation is unclear concerning prior bypass surgery and the location of the CAD, you should check with your cardiologist. After you confront him enough times and explain that this information is necessary for billing purposes, your cardiologist will probably start documenting the location of the CAD.

Example 3: Your cardiologist admits a CAD patient with angina. On a previous admission, the patient underwent PTCA to a branch of the right coronary artery. During this admission, the cardiologist performs a cardiac catheterization, which identifies that the same vessel has reoccluded.

In this situation, you should report 414.01 for the atherosclerosis of the coronary artery. You would also include the secondary diagnosis 413.9 (Angina pectoris; other and unspecified angina pectoris).

Remember: As of Oct. 1, you should be using 414.2 (Chronic total occlusion of coronary artery) when the patient has a coronary artery 100 percent occluded for several months. Similarly, you'll use 440.4 (Chronic total occlusion of artery of the extremities) when a patient has 100 percent occlusion of an artery that supplies the arms or legs, Williams says.

Example: Suppose your cardiologist sees a patient with symptoms of angina and does a cardiac catheterization. From the results of the catheterization, he diagnoses 414.2. This code provides medical necessity for the physician to perform a CABG (33510, Coronary artery bypass, vein only; single coronary venous graft).

If you think 414.xx and 411.81 (Acute coronary occlusion without myocardial infarction) are synonymous diagnosis codes, think again.

You should use 411.81 if your documentation shows that some debris causes an acute blockage of a coronary artery. However, if your documentation shows that calcium and plaque have built up over time in the coronary artery (in other words, atherosclerosis), you can choose an appropriate code from the 414.xx series.

If you look at the notes under 411.81, you will see that this code excludes "obstruction without infarction due to atherosclerosis (414.00-414.07)," according to ICD-9. Therefore, 414.xx and 411.81 are not interchangeable.