Therapeutic apheresis is a medical procedure that involves removing whole blood from a patient, separating it into components, and then returning certain parts while removing others. This process eliminates harmful substances or abnormal cells circulating within the bloodstream. By precisely targeting and removing specific elements, therapeutic apheresis helps to mitigate disease progression and alleviate symptoms. This intervention can manage conditions that might not respond adequately to conventional therapies.
What is Therapeutic Apheresis?
Therapeutic apheresis separates blood into its constituent parts outside the body. During the procedure, a patient’s blood is drawn and channeled through an apheresis machine, which uses either centrifugation or membrane filtration to divide the blood. The remaining healthy blood components are then returned to the patient, often with a replacement fluid like saline or albumin if a significant volume of plasma is removed.
Two primary categories of therapeutic apheresis are employed. Plasmapheresis, also known as plasma exchange, targets the plasma component of blood, which contains antibodies, toxins, or abnormal proteins. This method removes the plasma and replaces it with a substitute, reducing the concentration of harmful substances. Cytapheresis focuses on removing specific types of blood cells, such as white blood cells, red blood cells, or platelets, when their numbers are excessively high or they are dysfunctional.
Medical Conditions Treated
Therapeutic apheresis treats a wide range of medical conditions, particularly those involving autoimmune processes or abnormal blood cell counts. In autoimmune diseases like Myasthenia Gravis, apheresis removes autoantibodies that disrupt nerve-muscle communication. For Guillain-Barré Syndrome, plasma exchange removes circulating antibodies that attack the peripheral nervous system, reducing the severity and duration of neurological deficits.
Hematological conditions also benefit from apheresis. For instance, in Thrombotic Thrombocytopenic Purpura (TTP), plasma exchange removes harmful autoantibodies that inhibit the ADAMTS13 enzyme and supplies the functional enzyme through replacement plasma. Certain types of leukemia, such as acute myeloid leukemia (AML) with hyperleukocytosis, may require leukapheresis to rapidly reduce dangerously high white blood cell counts. This reduction helps prevent complications like organ damage caused by blood vessel obstruction. Apheresis addresses the underlying pathological components in these diverse conditions, often stabilizing patients during acute phases of their illness.
The Apheresis Process
The therapeutic apheresis procedure involves preparation to ensure patient comfort and safety. Before the session, medical staff establish intravenous access, often in a large arm vein, similar to donating blood. If suitable veins are unavailable or long-term treatment is anticipated, a central venous catheter may be inserted into a larger vein in the neck or chest. This access point allows for efficient withdrawal and return of blood.
During the session, blood is continuously drawn from one line, processed by the apheresis machine to separate and remove targeted components, and then returned to the patient through another line. Patients are seated comfortably, and medical staff closely monitor vital signs like blood pressure and heart rate. A single session can last two to four hours, depending on the apheresis type and blood volume. Treatment frequency varies based on the medical condition and patient response, ranging from daily sessions during acute phases to weekly or monthly treatments for chronic conditions.
Managing Potential Side Effects
While generally safe, therapeutic apheresis can lead to side effects, which healthcare professionals manage. A common side effect is a temporary drop in blood pressure, causing dizziness or lightheadedness, often managed by adjusting the flow rate or administering intravenous fluids. A tingling sensation around the lips or fingertips, along with numbness, is caused by citrate. Citrate is an anticoagulant added to the blood to prevent clotting within the apheresis machine, and it can temporarily lower calcium levels.
This citrate-related discomfort is alleviated by slowing the procedure or administering calcium supplements, orally or intravenously. Some patients may experience fatigue during or after the procedure, which resolves within a few hours. Issues related to vein access, such as bruising, discomfort at the insertion site, or, rarely, infection, are also possible. Medical staff continuously monitor patients for these reactions, ensuring prompt intervention.