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Thromboangiitis Obliterans (TAO)

Last updated Sept. 13, 2019

Approved by: Maulik P. Purohit MD, MPH

Thromboangiitis Obliterans (TAO) is non-atheromatous (not related to cholesterol deposition) inflammation and occlusion of the small and medium sized arteries and veins of the lower and upper extremities.


What are the other Names for this Condition? (Also known as/Synonyms)

  • Buerger Disease
  • Presenile Gangrene
  • TAO (Thromboangiitis Obliterans)

What are Thromboangiitis Obliterans? (Definition/Background Information)

  • Thromboangiitis Obliterans (TAO) is non-atheromatous (not related to cholesterol deposition) inflammation and occlusion of the small and medium sized arteries and veins of the lower and upper extremities
  • It is thought to be caused by an auto-immune reaction against a type of connective tissue (collagen type I and III), which forms the walls of the blood vessels
  • There is a very strong correlation between tobacco use and this disorder. Almost all the affected patients have a strong history of tobacco smoking or chewing. Young and middle-aged male adults are affected the most by TAO
  • The most important symptom of Thromboangiitis Obliterans is severe pain in the legs on walking that is relieved with rest. In case of complications, there may be ulceration of the part of the foot, infection, and gangrene formation that may require amputation of the limb
  • Absolute stoppage of tobacco use is the most important treatment consideration. It is also the only preventive measure of Thromboangiitis Obliterans
  • The rate of limb amputation in smokers with TAO is very high. However, if smoking is quit, then the condition has an improved prognosis

Who gets Thromboangiitis Obliterans? (Age and Sex Distribution)

  • Thromboangiitis Obliterans is more commonly seen in the Indian subcontinent. Natives of India, Korea, Japan, and Israeli Jews of Ashkenazi descent, have a high incidence of the condition
  • TAO generally affects male adults between 20-45 years of age. It is 3 times more common in males than females, due to increased incidence of smoking

What are the Risk Factors for Thromboangiitis Obliterans? (Predisposing Factors)

Risk factors associated with Thromboangiitis Obliterans include:

  • Smoking is the key risk factor
  • High serum titer of endothelial antibodies: Individuals who have increased number of a specific type of antibodies in their blood, called endothelial antibodies, have an increased risk. Such antibodies attack the lining of the blood vessels resulting in significant inflammation, which in turn narrows the lumen of the blood vessels
  • Individuals with a certain genetic make-up have an increased risk of TAO. Those having specific gene types namely HLA-A9, HLA-A54, and HLA-B5 genes have an elevated risk

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Thromboangiitis Obliterans? (Etiology)

  • The cause of Thromboangiitis Obliterans is the inflammation of the inner layer of the blood vessel (endothelium) associated with chronic smoking, in the small and medium-sized vessels of the upper and lower limbs
  • This kind of inflammation attracts the platelets (a blood cell type that helps in clotting) to the site of inflammation and form clots. When the clots obstruct the blood flow, it causes ischemic damage to the part of limb distal to the clot

What are the Signs and Symptoms of Thromboangiitis Obliterans?

Signs and symptoms associated with Thromboangiitis Obliterans include:

  • Severe pain in the legs after walking a short distance that is relieved with resting (claudication pain)
  • With severe condition pain is observed also at rest
  • Paleness of the distal limb
  • Absence of hair and nails in the affected part of the limb
  • Ulcer on the toes or fingers
  • The above symptoms may be present in the absence of any clotting issues (hypercoagulability) and absence of any other source of emboli, such as atrial fibrillation and infective endocarditis.

How are Thromboangiitis Obliterans Diagnosed?

A diagnosis of Thromboangiitis Obliterans may include:

  • Complete evaluation of medical history along with a thorough physical exam
  • Blood test for detecting the presence of endothelial antibodies
  • Ankle brachial pressure index to compare blood pressure between lower limbs and upper limbs
  • Vascular doppler study of all four limbs to compare the blood flow
  • Angiogram to locate the exact site of the clot

Laboratory investigations are required only to rule-out other possibilities of clot formation such as:

  • Systemic Lupus Erythematosus
  • Nephrotic syndrome
  • Anti-phospholipid syndrome
  • Raynaud's phenomenon, due to Scleroderma or CREST syndrome
  • ECHO (echocardiography) to rule-out cardiac source of blood clot

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Thromboangiitis Obliterans?

The complications associated with Thromboangiitis Obliterans include:

  • Ulceration of the distal part of the limbs
  • Infection of the ulcer that may cause infection spread in blood, leading to sepsis
  • Gangrene formation on the distal limb necessitating amputations

How are Thromboangiitis Obliterans Treated?

Absolute cessation of tobacco use is the only definitive treatment currently available. Some of the treatment support measures for Thromboangiitis Obliterans may include:

  • Iloprost (prostaglandin analogue): It is thought to reduce the progression of gangrene formation associated with TAO
  • Use of well-fitting protective footwear to prevent foot trauma, and thermal or chemical injury
  • Early and aggressive treatment of any injury to the extremities, to prevent progression of the infection
  • Avoidance of cold environment
  • Avoidance of drugs that lead to vasoconstriction (narrowing of the blood vessels)

How can Thromboangiitis Obliterans be Prevented?

The only preventive measure of Thromboangiitis Obliterans is a complete abstinence from smoking.

What is the Prognosis of Thromboangiitis Obliterans? (Outcomes/Resolutions)

  • The prognosis of Thromboangiitis Obliterans is good for most individuals, if smoking is quit during early disease stage itself
  • The rate of amputation in smokers with TAO remains high; among those who continue to smoke

Additional and Relevant Useful Information for Thromboangiitis Obliterans:

Thromboangiitis Obliterans is not known to cause any fatalities.

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: May 26, 2015
Last updated: Sept. 13, 2019