Alberto J. Muniagurria
Peripheral arterial disease consists of the alteration of the arterial, venous and lymphatic systems.
Chronic peripheral arterial occlusive disease
Chronic peripheral arterial occlusive disease is a common clinical problem characterized by decreased supply of oxygenated blood to the tissues of the limbs. Its symptoms are characterized by a pain picture that is magnified with exertion, a circumstance in which there is a greater requirement for blood flow, and by progressive trophic changes linked to the lack of oxygen.
The most frequent cause is atherosclerosis, which mainly affects the lower limbs. When the disease occurs in young people, usually male, smokers and with upper limbs involvement, the most likely cause is obliterative thromboangiitis or Leo Buerger's disease. In this process, acute peripheral ischemia can develop without a prior history of arterial disease (Table 9-1).
Pathophysiology . Atherosclerosis is a disease of the large and medium-caliber arteries.
It begins when an injury to the arterial intima occurs through a loss of lining endothelial cells with exposure of smooth muscle cells to ceric lipids and circulating platelets, which causes lipid deposition, proliferation of smooth muscle cells, and formation of fatty streaks. Cell proliferation, which is the key event in atherogenesis, is stimulated by various mitogens, including low-density lipoproteins (LDL), and growth factors. derived from platelets, which act at the level of cell receptors. Thrombus formation and arterial vasoconstriction then occur in the area of endothelial injury, on the surface of the fibrous plaques, and mainly in the exposed necrotic areas of the ulcerated plaque. These mechanisms carry,
Flow can be suddenly reduced when plaque hemorrhage or detachment of a plaque fragment occurs with embolization in a distal territory
Regarding the risk factors for the development of atherosclerosis, the following can be said:
cholesterol. Levels above 200 mg / dl identify. people with potential risk; from 240 up the risk is high, and increases. with increasing values. High-density lipoproteins (HDL), in turn, mobilize cholesterol from peripheral tissues to the liver for excretion, and represent a protective factor against the development of vascular disease.
Cigarette . There is a direct dose-response relationship between the number of cigarettes smoked and chronic arterial occlusive disease.
Hypertension . It has a strong genetic component, also being linked to obesity and diet: high Na intake, low K and Ca intake.
The three mentioned constitute the main risk factors according to the latest population studies.
Age . In recent years it has become clear that the process of atherogenesis begins in adolescence, with an incidence of abrupt growth after 30-35 years.
Sex . The incidence is higher in males.
Family history . It is a risk factor when there is a history of vascular disease in youth.
Race . The black race is affected more frequently.
Diabetes . It is an especially important risk factor for the development of this condition. Sedentary life, stress, and the use of estrogens and progestogens induce a tendency to thrombosis.
|Table 9.1 Chronic peripheral arterial occlusive disease|
|3||Arteritis (collagen diseases, temporal arteritis, idiopathic medial aortopathy, or Takayasu disease)|
|4||Trauma (chronic occupational arterial occlusive disease of the hand and arterial entrapment|
Thromboangiitis obliterans is a non-atheromatous lesion of arteries, veins, and nerves. It characteristically affects the small arteries: of the hands and feet, with an intense inflammatory component that in the final stages leads to obstruction. arterial and venous. The pathogenesis is obscure, although the association with tobacco is clearly defined. Recently, alterations in humoral and cellular immune responses have been described.
Arteriovenous fistulas can be congenital or acquired. These; The latter are the consequence of trauma from penetrating wounds, malignant diseases, infections, or arterial aneurysms. Surgical arteriovenous fistulas are used for dialysis in chronic kidney failure.
In thoracic vascular compression syndromes, the neurovascular structures are compressed on their way out of the thorax and at the level of the neck due to the existence of cervical ribs that are attached to the first rib by means of bands of fibrous tissue.
Symptoms . The symptoms of circulatory insufficiency in the lower limbs are directly related to the lack of oxygen supply. Intermittent claudication, characterized by the appearance of pain with exertion, is related to its magnitude and the degree of arterial obstruction .. The location is in the gluteal area and the thigh in aortoiliac lesions, in the calf in the femoropopliteal injuries, and in the ankle and foot in the popliteal and tibiofibular trunk injuries. It is known as the sign of the stained glass window; the patient knows the distance he can travel and stops periodically to avoid or ease the pain, which disappears within a minute or two after stopping. It must be differentiated from pseudoclaudication due to herniated disc compression of the.
lumbar spine; the latter is relieved only by sitting and not by stopping. When it is associated with impotence in middle-aged men, it involves involvement of the terminal aorta and iliac arteries and is known as Leriche syndrome.
The other group of symptoms that acquires importance is constituted by those that appear at rest, and is characterized by pain, sometimes accompanied by paresthesia and tingling. This occurs when there are multiple levels of circulatory obstruction or due to the obstruction of a critical segment where the collaterals are also occluded. Rest pain appears in a horizontal position and tends to be relieved when the legs hang over the edge of the bed, which promotes blood flow. Ulceration and gangrene of the distal areas is the corollary of the evolution of this process. In patients with diabetes mellitus, the existence of peripheral neuropathy is added, with loss of tactile, thermoalgesic and deep sensitivity and sympathetic tone.
The ulcers accompanying neuropathy are painless and settle at pressure sites, eg, at level. of the head. of the metatarsals.
Obliterative thromboangiitis, more common in young male smokers, is characterized by a history of superficial phlebitis, Raynaud's phenomenon, and intermittent claudication in the upper and lower limbs.
Symptoms of tingling, paresthesia and pain in the upper limbs that appear in certain positions that compress the brachial plexus, suggest thoracic neurovascular compression syndromes; which are generally due to the presence of a cervical rib attached by fibrous bands to the first rib.
Signs. In chronic ischemic conditions, pallor and trophic lesions are observed in the lower limbs. The skin is atrophic, shiny and thin with. absence of hair, thickened nails with transverse and incised longitudinal bridges and accumulation of cornified material underneath, disappearance of subcutaneous cellular tissue, and muscle atrophy. On palpation the skin is cold, and it is confirmed. decrease or disappearance of one or more pulses.
A thrill may be palpated in the presence of an arteriovenous fistula. Murmurs are heard in the area of obstruction, which may become apparent after exercise. A continuous murmur points to the presence of an arteriovenous fistula, in which case the compression of the afferent artery makes it disappear. In the case of a large fistula, compression of the afferent artery causes reflex bradycardia (Branham's sign). Elevation of the affected lower limbs to 45º produces pale skin and venous emptying within 30 seconds (Table 9-2).
When lowering the legs the paleness takes more than 10 seconds to disappear, appearing a blush whose maximum intensity can be appreciated after 4 minutes. Likewise, there is a delay in venous filling, which, if it does not exist; Varicose veins should normally occur in a period of less than 15 seconds.
Allen test . It is used to determine the patency of the circulation at the level of the radial and ulnar arteries in the hand. With the patient's hand at rest, resting on the thigh, the physician's thumb compresses the radial artery until it collapses, and then the patient must alternately open and close the hand. If rapid arterial filling does not occur on opening of the hand, there is probable ulnar flow obstruction. Something similar occurs with the radial artery when compressing the ulnar.
Study methodology. It is based on records of hemodynamic activity and is completed with anatomical evaluation.
Hemodynamic evaluation consists of recording the pulse volume (plethysmography) and using the ultrasound Doppler technique.
The anatomical evaluation is carried out by means of two-dimensional ultrasound studies, which usefully and safely measure the configuration of the vessels from the abdominal to the popliteal aorta.
Arteriography is the most accurate procedure to determine the anatomical state of the arterial tree and is generally performed prior to surgery.
Acute arterial occlusive disease
Sudden blood flow occlusion produces a set of symptoms and signs that vary with the location and extent of the injury and with the presence or absence of collateral circulation.
Pathophysiology . The most common causes of acute arterial occlusion are embolism and thrombosis. Embolism originates in the vast majority of cases in clots detached from the heart by arrhythmias such as atrial fibrillation, or by myocardial infarctions, rheumatic valve disease and endocarditis. bacterial; it rarely comes from a left atrial myxoma.
Arterial thrombosis occludes vessels previously injured by atherosclerosis.
Symptoms and signs . The onset of acute arterial occlusion occurs rapidly in one to two hours, and is preceded or not by symptoms and signs of chronic arterial insufficiency according to the existence or not of previous obstructive disease. The predominant symptom is pain, which begins in the form of tingling and paresthesia, to transform in a short time into very severe pain. It is accompanied by coldness, numbness, paleness, and weakness.
The signs are characterized by a distal decrease in temperature, which is determined with the back of the hand, and comparing it with that of the other limb. Pulse asymmetry is an important sign.
Sometimes the pulse width near the occlusion may be greater than in the unaffected limb. The affected limb has a paler color, mainly when it is in a pending position.
There is a loss of tactile and painful sensitivity as the condition progresses. Subcutaneous hemorrhages, muscle contractures, and focal areas of gangrene occur within a six-hour period.
Arrhythmias and murmurs may be found as an expression of the origin of the embolus.
Study methodology . The history and physical examination establish the diagnosis. It is important to assess the extent of the occlusion and the anatomical state of the collateral circulation using the
Doppler and arteriography, which can provide important information.
|Table 9-2. Duration of paleness with elevation of the limbs|
|Degree of paleness||Lifting duration|
|0||No paleness in 60 seconds|
|1||Defined paleness in 60 seconds|
|2||Frank pallor in 60 seconds|
|3||Defined paleness in 30 seconds|
|4||Horizontal level paleness|
Varicose veins generally affect the greater and lesser saphenous venous systems. They are dilated, tortuous, valved, incompetent veins. A real hereditary link has not been demonstrated and the etiology remains obscure; in women it is aggravated by hormonal factors in the course of puberty and menopause, or with increased intra-abdominal pressure as occurs in pregnancy.
They can be primary or secondary. The primary ones are due to the lesion of the vessel wall or alteration of the venous valves; those secondary to obstructive processes of the iliofemoral vein or the cava.
Successive episodes of venous thrombosis produce irreversible changes in the venous wall and valves that cause chronic residual symptoms.
During the muscular activity of the gait, the veins are squeezed, producing centripetal and centrifugal circulation, as well as towards the perforators and therefore towards the superficial venous system.
This play of pressures, over the years, leads to the characteristic symptoms and signs of post-thrombotic syndromes.
Symptoms and signs . They produce aesthetic alterations followed by manifestations caused by complaints of heaviness and fatigue that are accentuated with the passing of the hours. Elevation of the lower limbs improves symptoms. Edema that increases throughout the day, pain, skin pigmentation and supramaleolar ulcers may occur successively. internal secondary to minor trauma. Subcutaneous fibrosis is added.
Study methodology . History and physical examination define the syndrome. The Doppler study and venography in doubtful cases complete the evaluation.
Acute venous occlusion or thrombophlebitis
It can occur in the superficial veins or in the deep venous system.
Superficial thrombophlebitis . It is of chemical cause or of unclear origin. The venous path is exquisitely painful, both spontaneously and on palpation. There is erythema and edema.
It is accompanied by a fever.
The study methodology includes questioning, physical examination and a Doppler to detect thrombosis of the affected segment.
Deep thrombophlebitis . It is one of the most common hospital vascular disorders. It is due to bed rest for prolonged illnesses, malignancies of the lung, pancreas and gastrointestinal tract, contraceptives, disseminated intravascular coagulation, postpartum complications.
The picture is characterized by the sudden onset of edema, mainly in the lower limbs, pain not related to exercise, which improves by raising the limb, dilation of the superficial veins, positive Homans sign, local temperature increase. Lung embolism may be the presentation of the picture.
Regarding the study methodology, the administration of fibrinogen labeled with 125I should be done before the initiation of thrombosis. The Doppler study and plethysmography help define the picture.
Lymphedema is the abnormal accumulation of lymph in the extremities, secondary to infectious processes with lymphatic thrombosis, parasites (filariasis) that obstruct the ducts, congenital due to lack of formation of the ducts, traumatic due to injuries, operations, burns, irradiations, allergic by exposure to drugs, associated with obstructions, venous, malignant due to obstruction and invasion by neoplastic cells; and idiopathic or essential (Milroy's disease).
It is characterized by a cold and painless edema; progressive, which improves little with rest, accompanied by secondary fibrosis and without godet. Color changes occur in late stages. They do not respond to diuretics. To study it, lymphography is used in selected cases.