Postthrombotic disease



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THE KURSK STATE MEDICAL UNIVERSITY

Department of surgical diseases № 1

POSTTHROMBOTIC DISEASE

Information for self-training of English-speaking students

The chair of surgical diseases N 1 (Chair-head - prof. S.V.Ivanov)


By professor O.I. Ochotnickov

KURSK-2010

Postthrombotic disease is the most severe clinical form of chronic venous insufficiency. The disease is wide-spread and leads to stable invalidism.

The term “postthrombotic disease” was proposed by Saveliev, and it’s determining pathological condition, which has developed after acute thrombophlebitis or phlebothrombosis in vein cava inferior system, including its subkidney part, iliac veins and main deep veins of lower extremities.

Acute deep venous thrombosis in limbs leads to postthrombotic disease in 90-96%. The syndrome caused by acute iliac venous thrombosis first of all, then by leg deep venous thrombosis. Independently from initial point of venous thrombosis it develops in both - ascending and descending directions. Due to venous occlusion severe blood hypertension appears lower it. It leads not only to main deep vein dilation, but to muscular once too. Due to venous hypertension collateral blood out flow ways are opening.

Acute venous thrombosis transforms into stable occlusion or changed by recanalization of the vein.

Prevalence of stable occlusion or recanalization depends on local circulative peculiarities in veins. In vein cava inferior system there are some zones, where recanalization is more frequent final of acute venous thrombosis, and there are another once with high frequency of stable postthrombotic occlusion. For example, venous segment between deep femoral vein opening and long scaphen vein once is characterized by very intensive blood outflow, so occlusive venous thrombosis in the zone has been being met too rare and it leads usually to reconalization. Stable occlusion appears more often in the general iliac vein and the superficial femoral vein due to rich rate presence for collateral blood outflow in this areas.

In cases of muscular venous thrombosis there are no severe blood outflow damages due to it realizes, first of all, through deep and superficial veins. Besides, high functional activity of leg muscles leads to increase of blood flow through them. So, usual exit of acute muscular venous thrombosis reconalization is. Thrombosis and recanalization lead to venous valves destroying and retrograde blood flow appears.

In development of postthrombotic disease venous hypertension is the most important lesion factor, but not so due to veins obstruction as retrograde blood flow appearance. It leads to decrease of venous blood outflow velocity and ,so, according Bernuli law, to intravenous blood pressure increase. Retrograde blood flow promotes pathological changes in leg soft tissues, microcirculative bad and veins dilation. Destroying role of retrograde blood flow occurs after venous thromb reconalization immediately. Valves destroying is realized due to two mechanisms - direct damage during thromb reconalization and indirect - due to vein dilation. It leads to relative valve insufficiency, thromb recanalization to absolute once.

So, at walking time, due to influence of muscular contraction centropital and retrograde blood flow appears and it’s presented in muscular relaxation too.

Besides, retrograde blood flow occurs to lower extremities from the vena cava inferior due to intraabdominal pressure changes. This pathological blood flow is meeting even in cases of partial iliac veins obstruction through collateral pelvic veins. They haven’t any valves and transform to great dilated veins.

Thromb recanalization is the most often result of acute venous thrombosis. Thromb retraction, organization and thrombolisis begin together with its appearance and its recanalization has being finished from some months to 3 years.

In cases of primary iliac vein occlusion, blood hypertension and dilation occur in lower limbs veins in accompany with additional descending thromb formation.

In cases of ascending thromb growing from leg deep veins into femoral once, they become empty due to venous blood outflow decrease. There isn’t their dilation, spasm may be more frequent. So, thrombing femoral vein can be narrowed.

Postthrombotic disease can develop on background of varicose disease or its predisposition. Peculiarities of this disease include more severe deep vein dilation and more often thrombreconalization. Initial deep veins condition is proved to influence to acute venous thrombosis future. Initial spasm condition leads to thromb organization with vein sclerosis, in another once - to recanalization. So, usually, segmental postthrombotic occlusions are more characterized for initial normal veins, thrombrecanalization - for background varicose disease predisposition.

On background of acute venose occlusion some ways for collateral blood outflow are appearing. Centropital outflow direction is meeting only. On that time intravenous blood pressure is very high. When same thromb recanalization occurs, vein blood outflow is changing. And if in muscular contraction phase blood outflow direction has been being kept, in relaxation once blood pressure decrease in accompany with valves absence in venous collaterals lead to retrograde blood flow appearance. And if in initial stage on background of acute venous occlusion vascular collaterals are dilating due to high intravenous hypertension only, in postthrombotic disease development their dilations are connected with retrograde blood flow appearance. During recanalization the dempfer function of venous collateral is decreasing and has been being transformed into ways for pathological retrograde blood flow.

Besides intravenous changes some fibrose once take place in near vein tissues, and sclerotic paraphlebitis occurs.

It’s important to distinguish two sorts of pathomorphological changes in postthrombotic disease development. In first case postthrombotic changes are limited by main deep veins only. And simultaneous muscular veins changes are functional. But if thrombosis comes intomuscular veins too, their changes will be organic.

In postthrombotic disease transcapillary metabolism is changed in muscular and fat tissues.

Capillary permeability increases for blood proteins and decrease for oxygen supply. Arterial-venous shunts become active. Colloid-osmotic intertissue pressure is increased, due to proteins and electrolytes coming out with tissue oedema appearance.

There are no any strict border between acute venous thrombosis finishing and postthrombotic disease beginning, but they are, of cause, different pathological conditions.

First of all, acute deep venous thrombosis haven’t leaded to postthrombotic disease always. At second, pathogenesis of postthrombotic disease and acute venous thrombosis are different.

So, postthrombotic disease is chronic venous disease of limbs, developing due to acute deep venous thrombosis in vein cava inferior system. It’s conditioned by severe venous outflow lesions, simultaneous damages of lymph outflow and microcirculatory changes.

Clinical picture includes in itself increase of fatiguability, leg pain, oedema, subskinal veins dilations, recurrence of acute thrombosis. Later, skin hyperpigmentation, fat tissue induration and trophic ulcers appear.
In postthrombotic disease development very important significance belongs to initial condition of lower limbs venous system. In one half of patients with acute venous thrombosis have varicose disease or predisposition for it. And severe dilation of subskinal veins gives possibility for creation of varicose form of postthrombotic disease diagnosis.

Usually, sclerotic form is arriving against a background of primary normal veins. So, there are two clinical forms of postthrombotic disease - varicose and sclerotic once.

Besides two clinical forms of the disease, there are 3 stages.

Clinical form can be determined by general examination. In 1 stage of sclerotic form of postthrombotic disease there are no pathological superficial veins dilations. In 2 and 3 stages varicous changes appear, but they aren’t so severe and localize in region of incompetent communicating veins. Main subskinal veins haven’t varicies. But indurative process in fat tissue and skin hyperpigmentation on leg are more severe, then in cases of varicose form.

In sclerotic form testaceous fibrose may be in lower one third of leg. There are no oedema here due to severe tissue induration, but it localizes some upper.

In cases of varicose form of postthrombotic disease varicous transformation of subskinal veins are expressed. There are all signs of varicous disease, but they are redouble by severe blood outflow lesions in deep veins.

In first stage oedema of fat tissue puts on a mask of varicose dilation. But in second stage this dilation is more severe.

It’s very important, that limb oedema after acute deep venous thrombosis is the most important sign of postthrombotic disease.

Morphologicaly 1 stage of postthrombotic disease conforms to stage of deep veins occlusion. And recanalization finishing means transformation of 1 stage into 2 once. Clinically, beginning of the 2 stage is conformed to presence of trophic changes - tissues hyperpigmentation and induration in leg lower one third. This changes are conditioned by retrograde blood flow in deep veins.

In 3 stage trophic ulcers appear. Peculiarities of venous blood outflow are the same, as in 2 stage. But spreading of indurative cellulitis areas are accompanied with lymph insufficiency. So, 3-d stage of postthrombotic disease is named chronic lympho-venous insufficiency.

Besides clinical forms and stages of postthrombotic disease venous outflow condition determination is very important. They are subcompensation and decompensation.

Obviously there are no direct accordance between disease stages and venous outflow condition. First stage of the disease conforms to deep veins occlusion, so venous outflow lesions are the most severe. But in 2 and 3 stages after reconalization of deep veins blood outflow improves. Clinically it’s manefistated by oedema decrease. And trophic changes in it are connected not so with venous congestition, but with retrograde blood flow.

Usually, in 1 stage patients fell themself badly, disease manifestations are more painful, then in 2 stage, when trophic changes appear. Postthrombotic disease heaviness is characterized by venous outflow condition.

Besides clinical forms, disease stages and venous outflow condition, sort and localization of venous lesions are distinguished. The lesions includes occlusion, total and partial reconalization. According using classification diagnosis can be following, for example, “postthrombotic disease of right lower extremity, sclerotic form, 2 stage, partial reconalization of left iliac vein, occlusion of left femoral vein, reconalization of leg deep veins, decompensative condition of venous blood outflow.

Diagnose

Subjective signs are following: pain, increased fatiguability of lower extremity, gastrocnemius muscle cramps, skinal pruritus.

Objective clinical sings include oedema, varicies transformation of subskinal veins, hyperpigmentation, fat tissue induration, trophic ulcers.

Lower leg one half is the zone of the most severe local manifestation of the disease.

Ultrasound examination and phlebography are the most valuable instrumental methods. Ascendency phlebography gives information about permeability of deep lower limbs veins, gives possibility to find occlusive zones and some collateral vessels, presence of incompetent communicating veins. Descendance retrograde phlebography gives information about venous valves localization and their condition. Valves destroying isn’t total in postthrombotic disease. So, information about valves localization and their functional condition gives possibility for choice of rational correction mode. Besides, retrograde phlebography exposes ways of collateral outflow too. But their number is smaller, then that is gave by ascendency once.

Obviously, the results comparison of those methods has complete information about veins blood outflow.

Surgical treatment of postthrombotic disease includes conservative therapy and surgical once. Presence of contraindications for surgical management is the base for conservative therapy only. There are no general surgical procedures according clinical forms or degrees only. Only individual examination of lower extremity venous system condition due to phlebography and US-scanning give real possibility for correct choice of treating mode.

In 1 stage of postthrombotic disease surgical treatment is contraindicated. subskinal and perforating veins are natural ways for collateral blood outflow rounding deep veins in occlusion.

Some indications for surgical correction appear after reconalization finishing in deep veins, when pathological retrograde blood flow occurs. So, the 2-d stage of the disease is the indication for surgical procedures.

In patients with sclerotic form of the disease in 2-d stage there are some indications for local ligation of incompetent communicating veins only. Of cause, in cases of long scaphen vein complete value.

Usually, in 2-d stage of postthrombotic disease there are indications for wide-spread use of some plastic and reconstructive surgical procedures.

In 3-d stage indications for surgical correction appear more often, but their results become more bad. Surgical correction in patients with 3-d stage expediency to use after therapeutical treatment of trophic ulcers.

The main principle of surgical management of postthrombotic disease includes venous outflow correction by restorative and reconstructive procedures. And, at last place - the use of subskinal veins ablations and ligations of perforating veins.

Among reconstructive surgical procedures Palm-Esperon and Thayer-Warren procedures are the most wide-spread. Palm-Esperon procedure includes creation of venous bypass between iliac veins due to the long scaphen vein. Venous blood from ill extremity is shunting into iliac vein of another side.

Thayer-Warren procedure includes artificial anastomosis creation between long scaphen vein and femoral or popliteal veins on the same side. The purpose of the procedure is bypassing occlusive zones in femoral or leg deep veins.

Communicative insufficiency is very severe in cases of Postthrombotic disease. It leads to trophic lesions. So it’s necessary to ligate them. More often it’s realizing due to Linton procedure. It includes subfascial ligation of communicating veins through posterior longitudinal incision on leg back side.



Valves correction can be reached by free valves transplantation, exstravessel correction with the use of special devices /spirals/ or by different modes of extra-intravenous valves corrections.


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