Acute venous and arterial occlusion – Treatment

Arterial occlusion

Sudden occlusion of an artery (carrying oxygen-rich blood from the heart to the periphery) gives rise to an acute arterial occlusion. This is most commonly due to thrombi (blood clots), carried by the blood stream either from the heart or another part of the body as a so-called embolus, or local thrombus formation following injury to the vessel wall, by underlying calcified plaques, for instance. Rarer causes include so-called paradoxical emboli (passage of a blood clot from the venous to the arterial system through a congenital defect in the cardiac septum), congenital coagulation disorders, cancer, etc.

An embolus arises in the heart mostly in cases with underlying atrial fibrillation. This may then occlude any peripheral vessel, from cerebral arteries (with risk of stroke) to intestinal arteries (with risk of reduced supply to the intestine and tissue death of parts of the intestine) and the arm or leg arteries (with risk of amputation). Local thrombi may also develop in all these arteries.

Time is a critical factor in acute vascular occlusion, since the longer the absence of adequate blood supply to dependent tissue , the higher the risk of irreversible damage.

Therapeutic options

These include open surgery and percutaneous interventional therapy:

Open surgical procedures include the so-called Fogarty’s thrombectomy, especially used for occlusion of arm and leg arteries. The procedure is performed under general anesthesia with exposure of an easily accessible vessel (usually an artery in the groin). The vessel is then opened by an incision and a Fogarty catheter (named after the person who first described it) introduced into the vessel and negotiated across the occluded segment. This catheter is provided with a balloon at its front end which may be filled by a syringe at its rear end. Once the catheter negotiates the thrombus, the balloon is filled and is withdrawn together with the blood clot. Contrast medium and x-rays are then used to check for the presence of any residual thrombus in the blood vessel.

Various interventional techniques may be alternatively employed. An easily accessible vessel is thereby punctured through the skin with a needle, over which wires or a catheter are introduced. Local anesthesia usually suffices for the procedure. The blood clot can then be suctioned out (aspiration thrombectomy) or dissolved by medication allowed to run into the vessel for several hours (lysis).

The treatment strategy best suited for your condition will be decided by your treating physician,  and will depend on your general health and the site of occlusion, amongst others.

Preparation and aftercare

You  cannot usually be prepared for this as a patient since the disease is sudden in onset.

You will be administered blood thinners in hospital after being treated for a vascular occlusion. The source of the embolus ( in case this was not a local event) will also be searched for; investigations such as an ultrasound of the heart, blood tests or computer tomography and other tests may be necessary. Further therapy will be discussed with you depending on the situation. If you are found to be have atrial fibrillation (the most common cause), continuing therapy with blood thinners is necessary in most cases. Evaluating the cause is important in order to prevent recurrence of acute vascular occlusion.

Venous occlusions

Venous occlusion  (veins transport oxygen-poor blood from the periphery to the heart) is usually less dramatic than an acute arterial occlusion. One or a combination of the factors mentioned below may give rise to  venous occlusion: increased viscosity of blood, reduced blood flow velocity, damage to the vessel wall.

Leg veins are the most common site of a venous occlusion, but any vein in the body may be affected. Involvement of a superficial vein (occasionally associated with an inflammatory reaction) is known as thrombophleblitis, while involvement of deep or the so-called truncal veins is known as deep vein thrombosis (DVT).

Occlusion of leg veins causes destruction of venous valves, which are important for continuity of blood flow back to the heart. Prolonged venous occlusion may therefore give rise to stasis of venous blood in leg veins and in turn lead to development of varicose veins, also known as chronic venous insufficiency.

An ultrasound examination is important for the diagnosis of venous occlusions in addition to other usual investigations.

Modes of therapy

Treatment of thrombophlebitis is conservative in most cases and includes local therapy with heparin ointment or heparin injections into the subcutaneous fat, elevation of the arm/leg and compression therapy with wrapping depending on the site of involvement. Compression stockings are also provided for leg veins. Cold compresses, antibiotic therapy if necessary, and analgesics may help in case an inflammatory reaction is associated.

Most cases of DVT are treated with blood thinners, with tablets being given for several months; the duration of treatment depends on the site of involvement. Compression bandages are also applied and therapy continued for several weeks to months. The venous system is re-examined  by ultrasound a few days later in order to assess the size of the blood clot. You may move about normally while undergoing this treatment.

An alternative to the conservative approach is open surgery or percutaneous interventional restoration of vascular patency. However, this is usually only recommended for pelvic veins in patients with severe symptoms due to stasis of blood in the leg.

Open surgery involves exposure of the femoral vein and removal of the clot using the Fogarty catheter under general anesthesia, as described above. An artificial cross-connection between the femoral artery and vein (arterio-venous fistula) is usually created for a period of three months to increase the pressure in the venous system and thereby prevent immediate re-occlusion. This is then closed operatively after a period of three months.

Percutaneous interventions are mostly performed under local anesthesia and, as with arterial occlusions, usually involve suctioning of the clot. A stent is usually also inserted in order to keep the vessel open.

Precautionary measures

To reduce the risk of venous occlusion, drink plenty of fluids, especially at high temperatures, and move your legs regularly by muscle exercises during prolonged periods of sitting or standing.