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Coding Peripheral Vascular Disease With Rutherford’s

Use this classification to improve the specificity of acute or chronic ischemia.

Any time spent coding vascular surgery will eventually lead to learning about peripheral vascular disease (PVD). Though possible throughout any extremity, treatment for PVD is usually conducted in the legs, where a narrowing of vessels has caused lessened blood flow (stenosis) or outright occlusion.

Complete blockages range from deep vein thrombi (DVT) that began as free-floating emboli, to the gradual collection of plaques along vessel walls or in more complicated areas like bifurcations or other multiple branched splits within the arterial vascular system. This latter condition of thickening or hardening of arteries, known as atherosclerosis, is a common point of treatment before an artery becomes fully blocked, requiring invasive surgery to remove large clots or the need for bypasses around occluded vessels.

The rudimentary coding needed to classify this diagnosis is ICD-10-CM code I73.9 (Peripheral vascular disease, unspecified). Simple and vague, it covers the easiest and worst of PVD — intermittent claudication, peripheral arterial occlusive disease (PAOD), and the like.

In my experience, that’s about all a surgeon will offer as diagnosis. However, a tried-and-true vascular surgeon may offer something more definite as a patient’s condition worsens. Instead of PVD or peripheral arterial disease (PAD) scrawled on an office ticket, the surgeon might document “Rutherford,” followed by a number between 1 and 6.

Peripheral vascular disease (PVD) medical term

In 1986, Robert B. Rutherford, MD, along with others in the field of vascular surgery, brought forth a new classification system that set the stages of diagnosis in the progression of ischemia throughout PAD. Since then, Rutherford’s Recommended Standards for Reports Dealing with Lower Extremity Ischemia was revised in 1997 and remains a standard in vascular surgery diagnosing.

Rutherford Classification

Initially, it’s important to gauge if the ischemia is acute or chronic: Chronic limb ischemia equals critical limb ischemia.

Acute Lower Limb Ischemia

  • Category I – Viable
  • Not immediately threatened
  • No sensory loss, no motor deficit
  • Category IIa - Marginally threatened
  • Salvageable with prompt treatment
  • Minimal sensory loss (toes only), no motor deficit
  • Category IIb - Immediately threatened
  • Salvageable with immediate revascularization
  • Sensory loss greater than toes; resting pain. Mild to moderate weakness
  • Category III - Irreversible
  • Major tissue loss inevitable
  • Profound sensory loss, anesthetic, profound paralysis (rigor)

Chronic Limb Ischemia

0  Clinical Stage: Asymptomatic

     No symptoms of claudication, ischemia

1   Clinical Stage: Mild claudication

      Mild pain, fatigue, or discomfort in muscle groups during exertion

2   Clinical Stage: Moderate claudication

      Moderate discomfort that limits but does not prevent ordinary physical activity

3   Clinical Stage: Severe claudication

     Severe pain with minimal activity (walking less than one block)

4   Clinical Stage: Resting pain

      Ischemic pain at rest, typically in the forefoot and toes

5  Clinical Stage: Minor tissue loss

     Ischemic ulceration (non-healing wounds, localized gangrene)
     Limited to digits or the forefoot

6  Clinical Stage: Major tissue loss

    Forefoot and beyond, frank gangrene

Coding Chronic Atherosclerosis

After a patient is observed and treated for acute PAD symptoms, their continued treatment begins. It’s at this point that medical coding is integral to following the progression of the patient’s chronic symptoms. The unspecified I73.9 doesn’t cover it anymore, and it’s up to the coder and the surgeon’s notes to keep a correct record of the continued diagnosis of ischemia.

Much like Dr. Rutherford offered a numbered list of ischemic examples, ICD-10-CM lists, numerically, the needed diagnosis codes for reporting lower extremity ischemia:

  • I70.20x (Unspecified atherosclerosis of native arteries of extremities)
  • I70.21x (Atherosclerosis of native arteries of extremities with intermittent claudication)
  • I70.22x (Atherosclerosis of native arteries of extremities with rest pain)
  • I70.23x (Atherosclerosis of native arteries of right leg with ulceration)
  • I70.24x (Atherosclerosis of native arteries of left leg with ulceration)
  • I70.25x (Atherosclerosis of native arteries of other extremities with ulceration)
  • I70.26x (Atherosclerosis of native arteries of extremities with gangrene)

(Variable x is placeholder for 6th character coding, usually denoting laterality or body part.)

Progressive Coding

From minor claudication to the ischemic death of tissue, this handful of codes allows vascular coders to better diagnose the progression of PVD, with the 5th character almost matching the numbered stage of Dr. Rutherford’s list. For nearly 30 years, Dr. Rutherford’s classification has stood the test of time, helping vascular surgeons to better document and follow the progression of disease that allows for smoother reporting by vascular coders. 

Jason M. Watson, BA, CPC
(A version of this article first appeared in the June 2026 issue of AAPC the Magazine)