Coronary artery disease (CAD) develops when the arteries that supply the blood to the heart muscles become hardened and narrowed due to a buildup of cholesterol and other materials, such as plaque, on their inner wall. It's also called atherosclerosis.

CAD is the most common type of heart disease and occurs in a wide range of patients. This chronic condition is the leading cause of death in the United States for both men and women. Usually, but not always, the complications associated with CAD are what lead to death, rather than the chronic condition itself, says Cheryl Ericson, MS, RN, CCDS, CDIP, associate director of education for the Association of Clinical Documentation Improvement (CDI) Specialists in Danvers, Massachusetts.

Atherosclerosis can reduce blood flow, and as a result it can decrease oxygen to the heart muscles. If the heart muscles don't get enough oxygen for long enough, infarction can result, leading to tissue necrosis or death, Ericson says. If it's only a brief lack of oxygen, the patient might develop chest pain, more specifically angina, which is a specific type of chest pain associated with CAD. Prolonged oxygen deprivation can lead to tissue death, which is an acute myocardial infarction (AMI). In addition, CAD weakens the heart muscles, thereby contributing to heart failure and different arrhythmias.

The thing that's tricky from a CDI perspective is that CAD is not something that typically needs to be treated in the inpatient setting, Ericson says. Physicians can usually monitor and treat patients very well in the outpatient setting. As such, CDI specialists need to look for the acute reason for the admission, that is, the new symptom associated with the chronic CAD, which is often the cause of the inpatient admission.

 

• E-mail
• Print
• PDF
• RSS
• ShareThis

Coding, CDI focus on heart disease differs

Briefings on Coding Compliance Strategies, February 1, 2015

Coding, CDI focus on heart disease differs

Coronary artery disease (CAD) develops when the arteries that supply the blood to the heart muscles become hardened and narrowed due to a buildup of cholesterol and other materials, such as plaque, on their inner wall. It's also called atherosclerosis.

CAD is the most common type of heart disease and occurs in a wide range of patients. This chronic condition is the leading cause of death in the United States for both men and women. Usually, but not always, the complications associated with CAD are what lead to death, rather than the chronic condition itself, says Cheryl Ericson, MS, RN, CCDS, CDIP, associate director of education for the Association of Clinical Documentation Improvement (CDI) Specialists in Danvers, Massachusetts.

Atherosclerosis can reduce blood flow, and as a result it can decrease oxygen to the heart muscles. If the heart muscles don't get enough oxygen for long enough, infarction can result, leading to tissue necrosis or death, Ericson says. If it's only a brief lack of oxygen, the patient might develop chest pain, more specifically angina, which is a specific type of chest pain associated with CAD. Prolonged oxygen deprivation can lead to tissue death, which is an acute myocardial infarction (AMI). In addition, CAD weakens the heart muscles, thereby contributing to heart failure and different arrhythmias.

The thing that's tricky from a CDI perspective is that CAD is not something that typically needs to be treated in the inpatient setting, Ericson says. Physicians can usually monitor and treat patients very well in the outpatient setting. As such, CDI specialists need to look for the acute reason for the admission, that is, the new symptom associated with the chronic CAD, which is often the cause of the inpatient admission.

Coding CAD in ICD-9-CM

ICD-9-CM codes for coronary atherosclerosis appear in the 414 series of codes. The codes include choices that describe the affected vessel(s):

• Unspecified type of vessel (414.00)
• Native vessel (414.01)
• Autologous biological vein bypass graft (414.02)
• Nonautologous biological bypass graft (414.03)
• Artery bypass graft (414.04)
• Unspecified type of bypass graft (414.05)
• Native coronary artery of transplanted heart (414.06)
• Bypass graft (artery) (vein) of transplanted heart (414.07)

Coding Clinic provided guidance on how to select the correct fifth digit to identify a native artery or a bypass graft in ICD-9-CM, says Shannon E. McCall, RHIA, CCS, CCS-P, CPC, CPC-I, CEMC, CCDS, director of HIM and coding for HCPro, a division of BLR, in Danvers.

"If the physician just used the term 'CAD' and we know the patient had a CABG [coronary artery bypass graft] procedure in the past without further identification in the documentation, it defaulted to an unspecified vessel," McCall says.

Coding CAD in ICD-10-CM

In ICD-10-CM, the default isn't necessarily the same, McCall says. In ICD-10-CM, the default is to a native vessel (I25.10) because even if a patient had a bypass, he or she still has atherosclerosis of the native vessel.

Coders will find the code for atherosclerotic heart disease of native coronary artery in subcategory I25.1.

Another difference between coding for atherosclerosis in ICD-9-CM and ICD-10-CM is the addition of combination codes in ICD-10-CM, McCall says. When it comes to CAD or arteriosclerosis, coders often have to use two categories of codes to fully describe a patient with CAD and also angina (e.g., 411.1) in ICD-9-CM.

If the patient does have angina in the setting of CAD, coders will choose a combination code in ICD-10-CM that identifies CAD and the presence of angina pectoris as well as its type, if specified.

If the patient does not have angina pectoris, coders will report I25.10 (atherosclerotic heart disease of native coronary artery without angina pectoris).

For patients with angina pectoris, subcategory I25.11- includes the following additional choices that further clarify the patient's condition:

• I25.110, atherosclerotic heart disease of native ­coronary artery with unstable angina pectoris
• I25.111, atherosclerotic heart disease of native coronary artery with angina pectoris with documented spasm
• I25.118, atherosclerotic heart disease of native coronary artery with other forms of angina pectoris
• I25.119, atherosclerotic heart disease of native coronary artery with unspecified angina pectoris

"We can assume a causal relationship between the coronary artery disease and angina, even if the provider puts them as two separate line items in a problem list," McCall says, which is important from an inpatient standpoint.

Sequencing is a significant problem with coding currently in ICD-9-CM because unstable angina typically brings the patient into the hospital. The underlying cause, most commonly CAD would be assigned as the principal diagnosis McCall says.

"Right now we're using a Coding Clinic that says if the person has a history of coronary artery disease and they have angina, you can sequence the CAD first," Ericson says.

Sequencing CAD first groups to a different MS-DRG than sequencing angina first; however, both of these MS-DRGs are very susceptible to denial for medical necessity.

"With these combination codes, the sequencing is a non-issue because it is a single code," Ericson says.

In patients with atherosclerotic heart disease of a native coronary artery, ICD-10-CM instructs coders to use an additional code, if applicable, to identify:

• Coronary atherosclerosis due to lipid rich plaque (I25.83)
• Coronary atherosclerosis due to calcified coronary lesion (I25.84)

Several of the codes in I25.11- also feature Excludes1 notes. In ICD-10-CM, an Excludes1 note is a pure excludes note and means the two conditions are mutually exclusive. A patient cannot have both conditions at the same time.

Notes under subcategory I25.11- exclude unstable angina or angina pectoris without atherosclerotic heart disease (I20.0-).

ICD-10-CM still includes codes for patients who have undergone a CABG and have CAD. Those codes will identify whether the CAD affects a graft or a transplanted heart.

The physician must document the type of graft, whether it is venous or arterial. That information may or may not be in the physician's documentation currently, McCall says.

"From a documentation standpoint, it may be helpful to ensure the physician identifies somewhere in the record that the patient had a CABG in the past," she says. "If they have had vessels bypassed, whether it involved usinhg thesaphenous vein or if it was a radial artery or if it was some other type of grafting, then it may be helpful to know if the CAD is affecting that graft."

The physician also needs to document the type of angina, if present. As with the other native vessels, ICD-10-CM includes combination codes for:

• Atherosclerosis of coronary artery bypass graft(s), unspecified, with angina pectoris (I25.70-)
• Atherosclerosis of autologous vein coronary artery bypass graft(s) with angina pectoris (I25.71-)
• Atherosclerosis of autologous artery coronary artery bypass graft(s) with angina pectoris (I25.72-)

The combinations specify the same choices for types of angina as the native vessel codes.

CDI and CAD

CDI specialists need to remember their role really isn't to memorize the codes, Ericson says. The coders are still going to be the ones doing code assignment.

"What you want to do is make sure there is precise documentation so the most accurate code can be assigned," Ericson says. That means CDI specialists must determine a query threshold.

"What I mean by that is, if the information is not going to have a significant impact on the claim, is it the role of CDI to query for additional specificity of the affected vessel?" Ericson says.

Coders want to know which type of vessel is affected by the atherosclerosis, but CDI specialists may not query for it because it's not going to affect reimbursement or quality metrics, Ericson says.

"As such, organizations need to determine who will query in these types of situations because it really becomes a coding accuracy issue rather than a claims submission issue," she says. "Unfortunately, it isn't possible to query for every unspecified code, so CDIs often have to limit their query efforts based on the department's mission."

The type of angina is very important. "One of the things we want to work on as CDI specialists is oftentimes the physician uses the term 'chest pain,' " Ericson says. Even cardiologists sometimes use it.

"Chest pain is too vague because it doesn't necessarily reflect a cardiac issue in terms of coding, so we need them to tell us if it's angina rather than chest pain," she says. "So we're going to have to try and get them away from using that language. We really want to know is there a cardiac issue and if so, what type of angina is present in this patient with coronary artery disease."

If the provider continues to use the term "chest pain," then CDI specialists should clarify whether the patient's chest pain is ischemic or non-ischemic.

"The reason why we would want to do that is because if it's ischemic chest pain, that is one of the ICD-10-CM inclusion terms for angina," Ericson says. "That's going to allow us to then take advantage of that relationship between coronary artery disease and angina that we have in ICD-10 that we didn't have in ICD-9."

She continues, "The physician has to always be very clear in saying what is causing the chest pain. If it's cardiac, that's an important finding. They should tell you it's a cardiac type of chest pain."

CDI specialists and coders want to make sure to look for any kind of clinical indicators of angina, Ericson says. Consider these questions:

• Did the physician order nitroglycerin?
• Did the physician order aspirin?
• Did the physician order oxygen?
• What else did the physician order for the patient?

"If you want that precise coding, you're going to look at whether or not there's a history of CABG," Ericson says. "If the patient has a history of CABG, we can't assume that the coronary artery disease is of the native vessel. Then you can even look for a history of a transplant, because then we definitely can't assume it's of the native vessel. It could be of the transplanted vessel."

CDI specialists will need to determine what level of detail makes the most sense for their organization, Ericson says.

"It's really a coding precision issue, and so we don't want to antagonize our physicians by querying too much on things that aren't going to have a huge impact in regards to what we're billing on our claims," she adds.

Editor's Note: This article originally published in the HcPro newsletter Briefings on Coding Compliance Strategies' February 2015 edition.