Atherosclerotic Peripheral Occlusive Artery Disease

It is a generic term used to describe different pathological processes of the peripheral arterial tree.

Summary

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• 1 Peripheral Arterial Disease
  • 1 Arteriosclerosis.
  • 2 The gangrene.
• 2 Pathological Processes
• 3 Concept
• 4 Pathogenesis
• 5 risk factors
• 6 Non-modifiable risk factors
• 7 Clinical Picture
  • 1 Subjective symptoms
  • 2 Physical signs caused by ischemia
    • 2.1 1. Inspection:
    • 2.2 2. Palpation:
    • 2.3 3. Auscultation:
  • 8 Differential diagnosis
  • 9 Treatment
  • 10 Sources

Peripheral arterial disease

Peripheral Arterial Disease occurs when there is a narrowing of the blood vessels outside the heart.

This happens when plaque, a substance made up of fat and cholesterol , builds up on the walls of the arteries that supply blood to the arms and legs. The plaque causes the arteries to narrow or become blocked. This can decrease or interrupt blood flow, generally to the legs , causing pain or numbness.

When the obstruction of blood flow is severe enough it can cause tissue death. If these pictures are not treated, it may be necessary to amputate the foot or leg.

A person with PAD also has an increased risk of heart attack , stroke, and transient ischemic attack. Plaque buildup in the arteries can often be stopped or reversed with changes in diet, exercise, and efforts to decrease high cholesterol levels and high blood pressure.

Arteriosclerosis.

Arteriosclerosis is a condition in which plaque is deposited along the walls of the arteries. Plaque is a sticky substance made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, this plaque hardens and narrows the arteries. This limits blood flow and can lead to serious problems such as: Coronary artery disease. These arteries carry blood to your heart. When blocked, you can experience angina or a heart attack.

Carotid artery diseases. These arteries carry blood to your brain. When blocked, you can have a stroke.

Peripheral arterial disease. There are arteries in your arms, legs, and pelvis. When blocked, you may experience numbness, pain, and sometimes infections.

Arteriosclerosis usually has no symptoms until the artery narrows too much or completely. Many people do not know that they suffer from this condition until they have a medical emergency.

A medical exam or other tests can reveal if you have arteriosclerosis. Treatments include medications, medical procedures, and surgery. A change in lifestyle. A healthy diet, healthy exercise, quitting smoking and managing stress can help a lot.

The gangrene.

Gangrene is the death of tissues in your body. This occurs when a part of your body loses its blood supply. Gangrene can occur on the surface of the body, such as on the skin, or inside the body, such as in muscles or organs. Causes include: Serious injury.

Problems with blood circulation, such as arteriosclerosis and peripheral arterial disease.

Diabetes.

Symptoms on the skin may include blue-black spots, numbness, ulcers that produce a foul-smelling discharge. If gangrene is internal, you may have a fever, discomfort, and the area may be swollen and painful. Treatment includes surgery, antibiotics, and oxygen therapy. In severe cases an amputation may be necessary.

Pathological processes

1. Peripheral occlusive arterial disease:
2. a) Atherosclerotic.
3. b) Not atherosclerotic.
4. Ectasiant peripheral arterial disease ( aneurysms ).
5. Inflammatory peripheral arterial disease ( arteritis ).
6. Functional peripheral arterial disease:
7. a) By vasoconstriction.
8. b) By vasodilation.
9. c) Due to exposure to cold.
10. d) Neurovascular syndromes.
11. Traumatic peripheral arterial disease.

In daily medical practice, the most common disorder is atherosclerotic occlusive peripheral arterial disease of the lower limbs; and, due to its high morbidity in the elderly, it is the one of most interest to the family doctor.

Concept

Obliterative arteriosclerosis is the segmental atherosclerotic narrowing or obstruction of the vascular lumen of the arteries supplying the extremities, most commonly affecting the lower limbs.

Pathogeny

Its epidemiology is that of atherosclerosis, a generalized process to all vascular beds; therefore, in the case of a patient with atherosclerotic manifestations at a given site, it can be thought that he has various degrees of damage at other sites, even when the process is clinically silent in the latter.

The maximum incidence occurs between 60 and 70 years of age, with a predominance of males. There is an increase in its prevalence in patients with arterial hypertension , hypercholesterolemia, diabetes and cigarette smokers.

Risk factor’s

Modifiable risk factors for atherosclerosis are as follows:

1. Smoking habit.
2. High blood pressure.
3. Hyperlipidemia.
4. Obesity .

In smokers there is an increase in incidence, and, in addition, the condition usually begins 10 years earlier. Good control of blood pressure and hyperlipidemia can reduce the incidence and degree of progression of atherosclerotic occlusive disease.

Non-modifiable risk factors

1. Age. The prevalence increases in both sexes after 50 years. The onset of symptoms occurs later in women, but the prevalence by gender is equal to around 70 years.
2. Male sex.
3. Diabetes mellitus . The association between diabetes and atherosclerosis is well established; There is evidence that strict control of hyperglycemia delays the clinical onset and progression of atherosclerosis, but it cannot be completely denied as a risk factor for diabetes, as the disorder in diabetics is ultimately more progressive. and encompassing – participation of distal vessels, generally below the knee.

The lower extremities are more frequently involved than the upper extremities. The commonly affected vessel is the superficial femoral artery, followed by the distal aorta, its bifurcation in the two iliac and popliteal arteries.

On its pathophysiology, arterial obstruction and narrowing are known to reduce blood flow to the limb during exercise, and in more severe cases also at rest. Symptoms and signs of the process are a consequence of ischemia.

The cross-sectional area of ​​the stenotic arterial segment is the most important factor in determining ischemia, because the vascular bed of the extremities has a high resting vascular tone and, therefore, great capacity for vasodilation, a moderate degree of stenosis. it is fully compensated by dilation of distal sites. Thus, when the affected vascular section area does not exceed 75%, the flow at rest is not affected. When the flow is permanently elevated, as occurs during exercise, a reduction of 60% of the vascular section area or more will imply a significant decrease in it. Vasodilation in response to ischemia depends on: local myogenic mechanisms, related to the reduction of intravascular pressure secondary to ischemia, and metabolic,

These local mechanisms compete with other neurogenic vasoconstrictors. Increased sympathetic activity from exposure to cold can induce ischemia in the presence of atherosclerotic obstructive arterial lesions.

Another determining factor of the presence or absence of ischemia is the development of collateral circulation. There are collateral vessels in the normal limb, but they are not used until there is obstruction of blood flow. Its opening is immediate after an acute arterial obstruction; but in chronic forms they require weeks and even months for their full development. This collateral circulation is controlled by adrenergic nerves.

Clinical Picture

Subjective symptoms

They appear with the significant reduction of the vascular section area greater than 60% of the lumen of the vessel. The most important symptom is pain, which will manifest itself according to the magnitude and severity of the underlying atherosclerotic process.

Intermittent claudication is usually the mode of onset of occlusive atherosclerotic disease of the lower limbs. Ischemia preferably affects the muscles; for this reason the pain appears during exercise and while walking, with the character of fatigue, cramps or tension and, sometimes, real pain that forces the patient to stop or slow down. Relieves with rest, to reappear once the patient has reached the distance at which he initially presented; This is called the walking perimeter and it is always the same for each patient. It is located in the calf, because the femoral is the most frequently compromised vessel, it can also be located in the thighs, hips and buttocks.

Rest pain occurs when there is a more pronounced decrease in blood flow and is a more severe form of the disease. In addition to muscles, nerve endings are affected. This pain is located in the forefoot or it can be of a sock-like distribution, usually it is burning and worsens at night, so that the patient cannot sleep and is only relieved when he leaves his feet hanging out of the bed; this appears to moderately increase flow due to the effect of gravity.

Other painful manifestations appear in the more advanced stages such as: pretrophic pain, ulceration and gangrene; the condition spreads to the subcutaneous cellular tissue; This pain is constant and localized in the damaged areas.

Other symptoms of the disease are: the feeling of coldness and paresthesias in the lower limbs.

Physical signs caused by ischemia

The most objective sign is the decrease or absence of arterial pulses, distal to the obstruction. In advanced cases, other signs can be evidenced through the different phases of the physical examination:

1. Inspection:

1. a) Paleness.
2. b) Cyanosis.
3. c) Permanent reddish or blue-reddish coloration: the so-called crustacean foot, which in cases with permanent severe ischemia is due to the persistent vasodilation of small capillaries, in response to sustained ischemia and the secondary accumulation of toxic metabolites.
4. d) Trophic changes: dry and shiny skin, disappearance of hair, brittle and thickened nails, and atrophy of muscle masses.
5. e) Ulceration and gangrene , in very severe cases.

2. Palpation:

1. a) Very low skin temperature (local coldness).
2. b) Decrease or absence of pulses: it is the most clinically important sign.

3. Auscultation:

1. a) Audible murmurs on the affected vessels, of a continuous systolic type.

For the clinical diagnosis in the family doctor’s office, first of all a patient with risk factors for atherosclerosis and evidence of it at different levels of their economy, who consults for pain, tension or cramp in muscle groups and who disappear or relieve with rest or momentary cessation of activity, the following aspects must be defined:

1. Establish the site of arterial obstruction.
2. Determine severity of ischemia.
3. Establish the appropriateness of the collateral circulation.

Palpation of arterial pulses and auscultation of murmurs are usually sufficient to determine the presence and site of arterial occlusion. Changes in skin color and temperature, as well as trophic changes, indicate the presence of ischemia and its severity. The Prats flush-pallor maneuver, which consists of raising the patient’s foot lying in the supine position, between 45 and 60 ° above the horizontal, and the results are evaluated as follows:

To assess the adequacy of the collateral circulation, the Samuels tests are performed -plantar ischemia when the foot is raised-, followed by the measurement of the color return time to the limb and the venous filling time, after placing it in a horizontal position -Surface venous filling time of Collens-Willensky-. A delay of more than 30 s in the return of color to the limb and venous filling indicates inadequate collateral circulation.

To confirm the presence of ischemia, the systolic blood pressure (SBP) is measured in the arteries of the lower extremity and also in the brachial artery, using a Doppler speedometer, so that when comparing the pressures thus obtained, its results in lower limbs never they should be less than 90% of the SBP in the brachial artery.

Currently, the measurement test for transcutaneous oxygen tension is used using special sensors for superficial dermal application; but they are not useful in case of cells and / or edema.

Another method of confirming arterial obstruction is arteriography, which allows the exact location of the occlusion to be determined.

Differential diagnosis

1. Arterial embolism. Its onset is sudden, the pain is very intense from the beginning, it does not alleviate at rest, it requires analgesics, even opiates, and measures that help restore flow to the limb; Furthermore, the limb is pale, waxy and extremely cold. Then it will become cyanotic and eventually gangrene will ensue. There are paresthesias followed by motor paralysis of the affected limb.
2. Intermittent claudication. It can also occur in cases with severe anemia, with venous disease and muscle phosphorylase deficiency; but, in all of them, the pulse is normal.
3. Other causes. Arthritis and herniated discs can cause pain in the lower limbs, but the pulse remains.

Treatment

1. Preventive. Prevention of this condition is modification of risk factors for atherosclerosis, and includes:
2. a) Stop smoking.
3. b) Decreased LDL-cholesterol, in hypercholesterolemic patients, through diet, exercise and lipid lowering drugs.
4. c) Maintenance of euglycemia in diabetics.
5. Non-pharmacological. The most important measure is a regular exercise program that allows these patients to develop adequate collateral circulation. In a period of 3 to 6 months, the patient must double his walking perimeter.
6. Pharmacological. Aspirin and other drugs with an anticoagulant effect have not been fully effective. Pentoxifylline, a hemorrheological agent that allows greater deformability of the red blood cell, has behaved with moderate efficacy, 400 mg every 8 hours is recommended via vo
7. Surgical. The following are indications to operate:
8. a) Pain at rest.
9. b) Non-healing ulcer.
10. c) Gangrene.