November 8, 2010

Coding for Peripheral Artery Disease
For The Record
Vol. 22 No. 20 P. 27

Peripheral artery disease (PAD) is a circulatory condition resulting in reduced blood flow to the extremities, typically the legs. The most common symptom is intermittent claudication (pain when walking), which resolves after a few minutes of rest. The location of the pain depends on the site of the narrowed or clogged artery. PAD may also be documented as peripheral vascular disease (PVD).

PAD, PVD, and intermittent claudication not otherwise specified are classified to ICD-9-CM code 443.9, which also includes peripheral angiopathy not otherwise specified and spasm of artery. If the PAD is due to diabetes mellitus, codes 250.7 and 443.81 are assigned, sequencing the diabetic code (250.7) first. Code 250.7 requires a fifth-digit subclassification to identify whether the diabetes is type 1 or type 2 and controlled or uncontrolled.

Another condition potentially related to PAD is atherosclerosis. Atherosclerosis of the extremities is classified to code 440.2. A fifth-digit subclassification is required to differentiate the type of atherosclerosis as follows:

• 440.20, Atherosclerosis of the extremities, unspecified;

• 440.21, Atherosclerosis of the extremities with intermittent claudication;

• 440.22, Atherosclerosis of the extremities with rest pain;

• 440.23, Atherosclerosis of the extremities with ulceration;

• 440.24, Atherosclerosis of the extremities with gangrene; and

• 440.29, Other.

Codes from subcategory 440.2x are considered a hierarchy. So if patient has atherosclerotic PAD (ASPAD) with gangrene, it is assumed the patient also has an ulcer. Do not assign codes 440.23 and 440.24 on the same record. If the patient has an ulcer with the atherosclerosis, according to coding directives, it is appropriate to assign a code for any associated ulceration (707.10 to 707.9) in addition to the 440.2x code. If the patient also has gangrene, then code 440.24 is assigned, but it is still appropriate to list code 707.1x as a secondary diagnosis to identify the skin ulcer type and site.

For coding purposes, the physician must document that the PAD is due to atherosclerosis before a code from 440.2 is assigned. For example, a patient is admitted to the inpatient setting with PAD and scheduled for below-the-knee amputation surgery. If the physician documents PAD throughout the medical record and the pathology report states atherosclerosis of the leg, then the physician should be queried for clarification. Without additional physician documentation, code 443.9 would be assigned. It would be inappropriate to assign a code from subcategory 440.2 in this case without the physician documenting ASPAD due to atherosclerosis. In fact, Coding Clinic advises to query the physician for further specification if the physician documents vague diagnoses as PAD or intermittent claudication (AHA Coding Clinic for ICD-9-CM, 1992, fourth quarter, page 25).

Subcategory 440.2 is used to classify atherosclerosis of the native arteries. If the patient has atherosclerosis of bypass graft of the extremities, then a code from subcategory 440.3 is assigned. The fifth-digit subclassification will depend on whether the bypass graft was an autologous vein bypass graft (440.31) or a nonautologous biological bypass graft (440.32). Code 440.30 is assigned for atherosclerosis of unspecified bypass graft.

The two main PAD treatment goals are controlling the symptoms and stopping the progression of the atherosclerosis. Medications may be used to treat PAD to prevent blood clots, lower blood pressure, decrease cholesterol, and control pain and other symptoms. In some cases surgery may be required. Angioplasty may be used to reopen the artery or a stent may be inserted to help keep the artery open. Angioplasty of the noncoronary vessel is classified to code 39.50. Insertion of stents are assigned to the following codes:

• 00.55, Insertion of drug-eluting stent(s) of other peripheral vessel(s);

• 00.60, Insertion of drug-eluting stent(s) of superficial femoral artery; and

• 39.90, Insertion of non–drug-eluting peripheral (non-coronary) vessel stent(s).

It is important to remember to assign at least two codes if a stent was inserted—one for the angioplasty and one for the stent insertion. Other codes are also necessary to identify the number of vessels the procedure was performed on (00.40 to 00.44) and the number of stents inserted (00.45 to 00.48). Another surgery performed for PAD is bypass surgery. Bypass surgery allows blood to flow around the blocked or narrowed artery. The most common procedure code for this surgery is 39.29, Other (peripheral) vascular shunt or bypass. The physician may choose to do thrombolytic therapy (99.10) to break up the blood clot in the artery.

Coding and sequencing for peripheral artery disease are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to more than 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.