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Coding for Peripheral Artery Disease

Peripheral artery disease (PAD) is a circulatory condition that results in reduced blood flow to the extremities, most commonly the legs. The most common symptom of PAD is intermittent claudication, or pain while walking that resolves after a few minutes of rest. The location of the pain will depend 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 or PVD is due to diabetes mellitus, codes 250.7 and 443.81 should be assigned, sequencing the diabetes-related code (250.7) first. Code 250.7 requires a fifth-digit subclassification to identify whether the diabetes was type 1 or type 2 and whether it was controlled.

Another condition that may be related to PAD is atherosclerosis, a widespread accumulation of fatty deposits in the arteries that may reduce blood flow to the legs, heart, and brain. 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. In other words, if a patient has atherosclerotic peripheral artery disease (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 a patient does have 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. Since it is considered a hierarchy, 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 type and site of the skin ulcer.

For coding purposes, a physician must document that the PAD or PVD is due to atherosclerosis before a code from 440.2 may be assigned. For example, a patient is admitted to the inpatient setting with PAD or PVD and is scheduled for below-the-knee amputation. If the physician is documenting PAD or PVD 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 or PVD due to atherosclerosis. In fact, Coding Clinic advises to query the physician for further specification if the physician documents vague diagnoses such as PVD 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 a patient has atherosclerosis of bypass graft of the extremities, then a code from subcategory 440.3 is assigned. The fifth-digit subclassification will depend if the bypass graft was an autologous vein bypass graft (440.31) or a nonautologous vein bypass graft (440.32). Code 440.30 is assigned for atherosclerosis of unspecified bypass graft.

Signs and Symptoms
Besides intermittent claudication, other common signs and symptoms of PAD include muscle pain or cramping in the legs or arms; leg numbness or weakness; cold legs or feet; poor wound healing on the toes, feet, or legs; color change in the legs; slower growth of toenails; shiny skin on legs; and a weak or absent pulse in the legs or feet.

The physician may order the following studies to aid in the diagnosis of PAD:
• Ankle-brachial index compares the blood pressure in the ankle with the blood pressure in the arm.
• Doppler ultrasound evaluates blood flow through arteries to identify blocked or narrowed arteries.
• Angiography follows the blood flow through the arteries using contrast material.

The two main treatment goals are controlling the symptoms and stopping the progression of the atherosclerosis. Medications may be used to treat PAD by preventing blood clots, lowering blood pressure, decreasing cholesterol, and controlling pain and other symptoms. In other cases, surgery may be required.

Angioplasty is a common procedure used to reopen an artery. During an angioplasty, a catheter is inserted into the blood vessel and directed to the affected artery. At that point, a balloon is inflated to push the plaque to the arterial wall and increase blood flow. Occasionally, a stent is inserted at this site to help keep the artery open. Angioplasty of the noncoronary vessel is classified to code 39.50. Insertion of stents is 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 (noncoronary) vessel stent(s).
It is important to assign at least two codes if a stent is inserted: one for the angioplasty and one for the stent insertion. Other codes are necessary to identify the number of vessels on which the procedure was performed (00.40 to 00.44) and the number of stents inserted (00.45 to 00.48).

Another surgery performed for PAD is bypass surgery, which 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.