What is therapeutic apheresis?

Therapeutic apheresis consists of the separation of blood components, as occurs when plasma is donated. The difference is that its purpose is to be a treatment.

Last update: September 11, 2022

Therapeutic apheresis is a extracorporeal circulation procedure that filters the blood by means of a device for therapeutic purposes. Its objective is the extraction and elimination of the components considered responsible for a pathology, without modifying the rest of the blood substances.

It is part of the purification procedures and, in addition, there are many therapeutic apheresis procedures that can be performed. It is used as a therapeutic alternative in certain diseases in which conventional treatment fails.

It is also known as therapeutic plasma exchangebecause separates plasma from blood cells with filtration or centrifugation. The first is generally used.

It resembles the hemodialysis procedure, except that it is capable of removing toxins bound to plasma proteins.

It required?

To perform therapeutic apheresis, the following is required:

  • vascular access that provides high blood flow: Vascular accesses similar to hemodialysis, such as arteriovenous fistulas or central catheters, are generally used. Only in some cases can a peripheral route be used.
  • Anticoagulation: with heparin or citrate.
  • Continuous monitoring: When the therapeutic apheresis procedure is performed, the person’s vital signs must be constantly monitored. Requires trained personnel and the use of monitors.

How does therapeutic apheresis work?

Two vascular accesses are used in therapeutic apheresis; one input and one output. This allows to produce a sterile circuit that makes the blood circulate extracorporeally. This circuit is connected to a special device that is responsible for filtering the components.

The harmful components remain in the filter, while the rest returns to the person through the other vascular access. In this way, immune complexes, autoantibodies, proinflammatory cytokines, heavy metals, toxins, harmful proteins, excess cholesterol, among others, are retained.

The procedure is similar to dialysis, although the filtration capacity is different.

Risks associated with its implementation

The risks of therapeutic apheresis are related to vascular access, anticoagulation, and the element that replaces the extracted plasma. For venous access, the use of large caliber catheters is required, which sometimes results in complications, such as hemorrhages, infections at the puncture site, thrombosis or even pneumothorax.

Also, anticoagulation creates a propensity for bleeding and, when citrate is used, the concentration of serum ionized calcium is reduced. This leads to symptoms of hypocalcaemia, such as paresthesias, nausea, vomiting, feeling cold, and cardiac arrhythmias.

On the other hand, since the extracted plasma has to be replaced with a replacement solution, to maintain the volume and oncotic pressure, two solutions are usually used: fresh frozen plasma or 5% albumin. This does not replace immunoglobulins, which creates a propensity for infections.

Transfusion reactions with fever and allergy may also occur.

Taking into account that a significant volume of circulating plasma is removed during plasma exchange, hypotension related to hypovolemia may occur. As well as other symptoms of hypoperfusion, such as dizziness, distal coldness or tachycardia.

Indications for therapeutic apheresis

Therapeutic apheresis is used to treat those pathologies that have the following characteristics:

  • They are caused by a pathogenic component is found in the blood.
  • This pathogenic component can be eliminated efficiently.
  • Elimination of the pathogenic component is faster than the production of the same.
  • The removal or reduction of the pathogenic component in the blood resolves or improves the symptoms.

In addition, although in most cases its indications are acute, in some cases its periodic implementation is required. It is indicated in conditions such as the following:

  • Familial hypercholesterolemia.
  • Cryoglobulinemia.
  • Multiple myeloma.
  • Waldenstrom’s macroglobulinemia.
  • Guillain Barre syndrome.
  • Raynaud’s disease.
  • Poison or drug intoxication.
  • Multiple sclerosis.
  • Lyme’s desease.
  • Antibody-mediated rejection of organ transplantation.
  • Idiopathic thrombocytopenic purpura.

There are different types of therapeutic apheresis

The main therapeutic apheresis treatments are plasmapheresis and cytapheresis. However, they are not the only ones, as the following are also included:

  • Immunoadsorption: one antibody or antigen is removed from plasma by combining with another.
  • double filtration.
  • Plasmadsorption.
  • Hemoadsorption.
  • Photopheresis: immunomodulatory therapy in which mononuclear cells are treated with photoactivatable drugs and then activated with ultraviolet light.
  • Rheoapheresis.
  • LDL-apheresis: Selective removal of low-density lipoprotein.
  • DALI: selective absorption of lipoproteins from the blood through ligands.
  • MARS: removal of substances bound to albumin.
  • Prometheus: removes toxins bound to albumin.

Plasmapheresis is the most common and separates the plasma components from the blood cells. On the other hand, cytapheresis lowers the specific blood cell count by removing white blood cells (leukapheresis), platelets (thrombocytapheresis), or red blood cells (erythropheresis).

The technique can select which component of the blood to filter, according to the needs of the patient.

An excellent alternative

Therapeutic apheresis is a therapeutic alternative in various diseases in which conventional treatment has failed. It is considered suitable, as long as it is capable of eliminate the harmful component at a faster rate than that produced by the body.

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