Peripheral Artery Disease – Symptoms, Treatment, ICD 9, Causes

What is Peripheral Artery Disease?

Peripheral artery disease (PAD) is a condition arising from the obstruction of the large arteries in the peripheral areas of the body such as the hands and legs. Peripheral artery disease is otherwise known as peripheral vascular disease (PVD) or peripheral artery occlusive disease (PAOD).

Obstruction in the arterial wall may result from inflammatory processes and atherosclerosis on the arteries causing thrombus, embolus or stenosis formation. The obstruction in the arteries often leads to ischemia.

Peripheral artery disease also includes micro vascular disorders involving constriction of the arteries such as Reynaud’s syndrome or dilation of the arteries such as erythromelalgia.

PAD affects up to 14% of the general population mainly affecting those ages 70 years old and above. Most of the cases are also asymptomatic and do not require extensive treatment and amputation. In fact, only 25% of the patients undergo treatment. Three out of 10 diabetics also suffer from PAD.

The obstruction associated with PAD also increases the risk of developing heart attack and stroke.

Peripheral artery disease is divided into four stages as introduced by Rene Fontaine last 1954:

1. Incomplete blood vessel obstruction, mild pain during walking (claudication).
2. Severe pain during ambulation involving only short gaps or distances (referred to as intermittent claudication)
3. Stage IIa- after walking a gap of greater than 150 meters
4. Stage IIb- after walking a gap of less than 150 meters
5. Pain during resting, aggravated by raising the limbs (rest pain)
6. Tissue loss and difficulty in ambulation (gangrene)

Rutherford introduced a more advanced categories including six types:

1. Mild pain
2. Moderate pain
3. Severe pain
4. Ischemic pain even when not involved in any activities
5. Slight tissue damage
6. Gangrene

Pathogenesis of Peripheral Artery Disease

Presence of any injury to the lining of the arteries causes inflammation to the area. This process results to clot formation and platelet aggregation forming a thrombus or plaque to heal the damaged area. Once this thrombus increases in size, it significantly reduces blood flow to the proximal areas of the clot. Stenosis also results, which is the narrowing of the lumen of the arteries as a result of atherosclerosis (build-up of fats). Reduction in blood flow causes reduced oxygenation leading to ischemia. The tissues undergo anaerobic metabolism releasing lactic acid from fats and proteins. The build-up of lactic acid causes pain and claudication. Chronic ischemia leads to death of the tissue or gangrene that needs amputation.

Furthermore, a thrombus can be dislodged and become an embolus. When this happens, the clot formation can lodge to small arteries in the heart or brain, leading to heart attack and stroke.

Causes and Risk factors

Risk factors of peripheral artery disease include:

Old age

The incidence of PAD increases as the age increases. People aged 70 years old and above are of greater risk for PAD because of reduced elasticity of the blood vessels.

Gender

Men are more prone to developing PAD because of certain habits such as smoking.

Smoking

Smoking is one of the major causes of PAD and increases the risk by tenfold. Nicotine in cigarettes is a potential vasoconstrictor which reduces the lumen of the arteries.

Hypertension

High blood pressure creates injury to the arterial walls leading to platelet aggregation and clot formation. Hypertension is also directly associated with cardiovascular and cerebrovascular accidents.

Hyperlipidemia

High levels of low-density lipoproteins (“bad cholesterol”) speeds up atherosclerosis which significantly blocks the arteries.

Diabetes Mellitus

Patients with diabetes also have increased risk for atherosclerosis formation due to sluggish blood flow brought about by high blood glucose levels. Most cases of leg amputations are associated with patients who are diabetic.

Signs and Symptoms of Peripheral Artery Disease

Most of the patients with PAD are asymptomatic. Other symptoms include:

Caludication

Claudication refers to pain, numbness, cramping and weakness of the extremities because of poor blood flow.

Wounds that heal slowly

Poor blood circulation to the injured area reduces the transport of white blood cells, platelets and clotting factors that help heal the injured part.

1. Cold, clammy skin on the affected part
2. Paleness or cyanosis of the extremities
3. Diminished nail and hair growth over the affected extremity
4. Weak and thready pulse in the affected limb, some serious obstructions may lead to absent peripheral pulse
5. Erectile dysfunction

Patients with PAD and diabetes may experience the symptom.

Diagnosis

Diagnostic test aims on determining any obstruction of blood flow in the peripheral areas of the body. Certain blood tests are also used to confirm presence of underlying factors such as hyperlipidemia. The tests include:

Ankle brachial pressure index

This test involves measuring the blood pressure in the arms and legs (particularly in the ankles). When the pressure of blood in the legs is lower than the pressure in the arms, PAD is suspected. Arterial brachial index ratio is also computed. ABI ratio of less than 0.9 is definitive with PAD. An ABI less than 0.8 indicate average disease and an ABI ratio of 0.4 is used as a baseline.

Doppler Ultrasound

Doppler ultrasound examines the blood flow to the limbs through the use of sound waves. A handheld device is placed over the affected areas. Sound waves are then converted to pictures of blood flow to determine any obstruction.

Treadmill test

ABI tests are done before and after the patient use treadmill. Significant changes in the ABI ratio during these times indicate severity of symptoms during a particular level of activity or exercise.

Arteriogram

Arteriogram involves the injection of a dye in the arteries and x-ray imagings are taken. This test determines any obstruction and the location as the dye passes through the arteries. Patients should be assessed for presence of allergies to seafood because the dye is composed of iodine based material.

MRI

Magnetic resonance imaging is one of the most accurate tests for PAD to locate the obstruction and describe the severity.

Blood tests

Cholesterol levels, triglycerides and blood glucose levels are determined to rule out any underlying conditions such as diabetes and hyperlipidemia.

Treatment of Peripheral Artery Disease

Treatment of PAD involves certain medication and lifestyle modification

Medications

Anti-platelet aggregate medications

Aspirin and clopidogrel are antiplatelet medications that reduce platelet aggregation to reduce thrombus formation. Ensure safety to prevent bleeding episodes and watch out for signs of bleeding in the body.

Antihyperlipidemics

Statin drugs such as simvastatin and atorvastatin inhibits the synthesis of lipid in the body.

Lifestyle Modification

Exercise

Exercise improves circulation and significantly reduces claudication. Treadmill or brisk walking is beneficial for PAD involving the lower extremities.

Smoking cessation

Cessation of smoking reduces the incidence of PAD and relieves symptoms

Lower blood pressure by means of diet and compliance to antihypertensive medications.

Surgery

Angioplasty

This involves the insertion of catheter balloon into the sclerotic artery to widen the lumen of the area.

Plaque excision or Arthrectomy

Plaque excision involves the scraping off of plaque inside the large arteries.

Bypass grafting

Grafting is done in areas of severe stenosis. The saphenous vein in the thighs is usually used to replace the stenosed artery. Artificial materials such as the Gore-Tez may also be used.

Sympathectomy

Sympathectomy is rarely done and involves removal of the nerves that innervate the area that cause vasoconstriction.

Amputation

Removal of the gangrenous area is the last resort to prevent further complications such as renal disease.

Complications

Conditions may arise as a result of continuous impairment in the circulation and embolus formation. Complications of PAD include:

1. Heart attacks and stoke
2. Severe ischemia leading to gangrene
3. Amputations of the gangrenous area

Complications may be prevented by instituting appropriate management and adhering with the suggestions and treatment.

Prevention

Prevention of PAD involves avoiding the modifiable risk factors such as:

1. Quit Smoking.
2. Avoid high fat content foods.
3. Ensure adequate daily exercise.

ICD 9 Code of Peripheral Artery Disease

The ICD or International Classification of Diseases is used to classify and code mortality data from a specific disease. The ICD code for PAD is 443. Specific codes for specific types of PAD include:

443 Other peripheral vascular disease
443.0 Raynaud’s syndrome
443.1 Thromboangiitis obliterans
443.9 Peripheral vascular disease, unspecified