Apheresis and dialysis are two advanced medical procedures that serve unique purposes. Apheresis focuses on removing specific components from the blood, such as plasma or white blood cells. In contrast, dialysis works to filter out waste products, toxins, and excess fluids, primarily in patients with kidney failure. Both procedures rely on specialized equipment to process blood outside the body before returning it. Comparing apheresis vs dialysis reveals their distinct roles in addressing different health conditions, showcasing their importance in modern medicine.
Key Takeaways
- Apheresis takes out parts of blood, like plasma or white cells, to help treat diseases.
- Dialysis works like kidneys by cleaning waste and extra fluids from blood. It is important for people with kidney problems.
- Apheresis is often used for diseases where the immune system attacks the body. Dialysis is needed for serious kidney damage or failure.
- Both treatments work well. Apheresis helps over 80% of patients with some illnesses.
- Knowing how apheresis and dialysis are different helps people choose the right treatment.
Apheresis: Definition, Purpose, and Process
What Is Apheresis?
Apheresis is a medical procedure that removes a specific component from the blood while returning the remaining components to the body. It serves both therapeutic and donor-related purposes. Therapeutic apheresis applications include treating diseases by removing harmful substances or cells from the bloodstream. Additionally, it plays a vital role in collecting blood components like plasma, platelets, and red blood cells for transfusions. In the United States, apheresis collected approximately 2.2 million units of platelets and 350,000 units of plasma in 2017. This process is also essential for producing plasma-derived medicinal products, such as intravenous immunoglobulin (IVIg) and albumin.
How Apheresis Works?
The apheresis process involves drawing blood from the patient or donor, separating it into its components using a specialized machine, and removing the targeted component. The remaining blood is then returned to the individual. Multifunctional devices like Octo Nova® and Immunosorba® are commonly used for this purpose. The procedure can be tailored to address specific needs, such as plasma exchange or cell removal. For example, therapeutic apheresis can mobilize plasma components from tissue depots, which is beneficial for conditions like familial hypercholesterolemia. The volume of plasma exchanged or treated is carefully calculated based on the patient’s plasma volume to ensure safety and effectiveness.
Common Conditions Treated with Apheresis
Therapeutic apheresis applications address a wide range of medical conditions. It is frequently used to treat immune-mediated neurological disorders, such as chronic inflammatory demyelinating polyneuropathy (CIDP) and myasthenia gravis. In a clinical study involving 3,425 patients, 82% responded positively to apheresis treatments. Other conditions include hematologic disorders, chronic lymphocytic leukemia, and familial hypercholesterolemia. Practice guidelines from expert committees support its use in these cases.
Therapeutic plasma exchange is another common application, particularly for managing immunologic disorders. This technique removes harmful antibodies or proteins from the blood, providing relief for patients with severe autoimmune diseases.
Dialysis: Definition, Purpose, and Process
What Is Dialysis?
Dialysis is a medical procedure that replaces the kidney’s function when it can no longer filter waste, toxins, and excess fluids from the blood. It is a life-saving treatment for individuals with kidney failure. This process also helps regulate blood pressure and maintain the balance of electrolytes in the body. Dialysis is commonly used in cases of acute kidney injury (AKI) and end-stage kidney disease (ESKD), where kidney function is severely impaired.
How Dialysis Works?
Dialysis removes waste and excess fluids from the blood using specialized techniques. Two primary types of dialysis exist: hemodialysis and peritoneal dialysis.
| Type of Dialysis | Mechanism Description |
|---|---|
| Hemodialysis | Blood is circulated outside the body through a dialyzer, which acts as an artificial kidney. A semipermeable membrane separates waste and toxins from the blood. The cleansed blood is then returned to the body. |
| Peritoneal Dialysis | The peritoneum, a natural membrane in the abdomen, serves as a filter. A sterile glucose solution (dialysate) is introduced into the peritoneal cavity. Waste and water move from the blood into the dialysate, which is later drained. |
In hemodialysis, blood flows through synthetic fibers in the dialyzer, where waste and water move into the dialysis solution. Ultrafiltration occurs by applying negative pressure to the dialysate compartment. Peritoneal dialysis involves multiple exchanges of dialysate daily to ensure effective waste removal.
Common Conditions Treated with Dialysis
Dialysis is essential for managing several kidney-related conditions. It is primarily used for:
- Acute kidney injury, which occurs suddenly and may require temporary dialysis until the kidneys recover.
- End-stage kidney disease, where only 10-15% of kidney function remains, making dialysis necessary for survival.
Globally, over 2 million people require dialysis for end-stage renal disease. In 2009, more than 1 million patients in the USA and Europe received renal replacement therapy. These statistics highlight the critical role of dialysis in modern medicine.
Apheresis vs Dialysis: Key Differences
Differences in Purpose
Apheresis and dialysis serve distinct purposes in medical treatment. Apheresis focuses on removing specific components from the blood, such as plasma, white blood cells, or harmful antibodies. It is often used to treat autoimmune diseases, blood disorders, and conditions requiring targeted removal of substances. Dialysis, on the other hand, primarily replaces kidney function. It removes waste products, toxins, and excess fluids from the blood in patients with kidney failure. While apheresis addresses specific blood-related issues, dialysis ensures the overall balance of the body’s internal environment.
Differences in Procedure
The procedures for apheresis and dialysis differ significantly. Apheresis involves drawing blood, separating it into components using a machine, and removing the targeted component. The remaining blood is then returned to the body. This process can be customized based on the patient’s condition, such as plasma exchange or cell removal. Dialysis, however, uses two main techniques: hemodialysis and peritoneal dialysis. Hemodialysis circulates blood through a dialyzer, which acts as an artificial kidney. Peritoneal dialysis uses the peritoneum in the abdomen as a natural filter. Both methods aim to cleanse the blood but differ in their mechanisms and equipment.
Differences in Medical Applications
The medical applications of apheresis and dialysis highlight their unique roles in healthcare. Apheresis is versatile, addressing conditions like myasthenia gravis, thrombotic thrombocytopenic purpura (TTP), and familial hypercholesterolemia. It also supports transfusion medicine by collecting blood components. Dialysis, however, is essential for managing acute kidney injury and end-stage kidney disease. Clinical studies provide further insights into these applications:
| Application Type | Description | Clinical Evidence |
|---|---|---|
| Therapeutic Plasma Exchange | Used to remove antibodies, immune complexes, and toxins. | Efficacy demonstrated in diseases like TTP, myasthenia gravis, and CNS demyelination. |
| Centrifugation-based (cTPE) | Preferred by transfusion medicine; higher extraction efficiency (86%). | Randomized controlled trials support its use in various clinical settings. |
| Filtration-based (mTPE) | Preferred by nephrologists; lower extraction efficiency (27%-53%). | Less effective for higher-molecular weight proteins; requires larger veins and higher flow rates. |
This table underscores the specialized nature of apheresis vs dialysis, emphasizing their distinct medical applications.
When to Use Apheresis or Dialysis?
Situations Where Apheresis Is Recommended
Apheresis is often recommended for conditions requiring the removal of specific blood components. It is particularly effective in treating autoimmune diseases and blood disorders. For example, therapeutic plasma exchange can remove harmful antibodies in patients with myasthenia gravis or thrombotic thrombocytopenic purpura (TTP). In some cases, apheresis has shown promise in managing chronic conditions. A case study highlighted its success in treating a patient with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), leading to full clinical remission. Additionally, a cohort study involving 27 patients with Long-Covid and chronic fatigue syndrome demonstrated a significant reduction in autoantibodies after therapeutic apheresis. These findings suggest its potential as a targeted treatment for similar conditions.
Situations Where Dialysis Is Recommended
Dialysis becomes essential when kidney function declines significantly. It is the primary treatment for acute kidney injury (AKI) and end-stage kidney disease (ESKD). Patients with AKI may require temporary dialysis to remove waste and toxins until their kidneys recover. For those with ESKD, dialysis serves as a long-term solution to maintain the body’s internal balance. Hemodialysis and peritoneal dialysis are the two main methods used, depending on the patient’s medical needs and lifestyle. Dialysis also helps regulate blood pressure and electrolyte levels, ensuring the body functions properly despite kidney failure.
Overlapping Scenarios and Combined Use
In rare cases, apheresis and dialysis may be used together. This combined approach is often necessary for patients with complex medical conditions. For instance, individuals with both kidney failure and autoimmune diseases might benefit from dialysis to manage waste removal and apheresis to target harmful antibodies. The integration of these treatments requires careful planning by medical professionals to ensure safety and effectiveness. While their purposes differ, the complementary nature of these procedures highlights their importance in modern medicine.
Conclusion
Apheresis and dialysis play vital roles in modern medicine, addressing distinct medical needs. Apheresis removes specific blood components, while dialysis replaces kidney function. Both procedures demonstrate high effectiveness in their respective applications. For example, more than 80% of patients treated with therapeutic apheresis (TA) alongside other therapies showed improvement. The complementary nature of these treatments enhances patient outcomes.
| Evidence Summary | Outcome |
|---|---|
| More than 80% of treated patients improved with TA, IVIG, immunosuppressive drugs, and/or HMAs. | Indicates high effectiveness of TA in renal diseases. |
| TA is primarily used as an adjunct to conventional immunosuppressive therapy. | Suggests complementary role of TA in treatment. |
| Various TA methods are technically complicated and expensive. | Highlights the need for cost-effectiveness studies. |
Understanding these differences empowers patients and caregivers to make informed decisions about treatment options.