Robert Shahverdyan
OVERVIEW
Chronic Kidney Disease
Understanding the Impact
Chronic kidney disease (CKD) is a serious condition that affects the kidneys' ability to function properly. It can lead to various complications and requires specialized care and treatment to manage effectively.
CKD is a progressive condition characterized by the gradual loss of kidney function, affecting the ability to filter waste and maintain fluid and electrolyte balance. It is a significant global health issue, with an estimated prevalence of 9–13% in the general population, often linked to conditions like diabetes and hypertension. If untreated, CKD can progress to end-stage kidney disease (ESKD), where the kidneys can no longer function adequately to sustain life without renal replacement therapy (RRT).
Patients with ESKD typically require either lifelong dialysis or a kidney transplant to survive, both of which carry substantial physical, emotional, and financial burdens. Dialysis, the most common treatment for ESKD, can be performed as hemodialysis in a clinical setting or peritoneal dialysis, which can be managed at home. Kidney transplantation is considered the gold standard for treating ESKD, offering better quality of life and longer survival compared to dialysis, but organ shortages remain a major challenge.
CKD significantly impacts quality of life, causing symptoms like fatigue, swelling, and anemia, and increases the risk of cardiovascular disease and infections. Early detection and management of CKD through lifestyle changes, blood pressure control, and medication can slow disease progression and reduce the risk of complications. Public health initiatives aim to raise awareness of CKD and its risk factors, as early intervention is critical to improving outcomes and reducing the economic burden. Advances in research, such as regenerative medicine and wearable dialysis devices, hold promise for improving the management of CKD and ESKD in the future.
Dialysis
Essential for ESKD patients
Dialysis is a life-saving treatment for patients with end-stage kidney disease (ESKD), serving as an artificial means to remove waste, toxins, and excess fluids from the blood when the kidneys fail. The two primary dialysis modalities are hemodialysis and peritoneal dialysis, each with distinct processes and benefits.
Hemodialysis (HD) involves using a dialysis machine and a special filter, called a dialyzer, to clean the blood. Blood is drawn from the body through a vascular access, passed through the dialyzer, and then returned to the body. This is typically performed three times a week for several hours at a clinic, but home-based options are also available. Peritoneal dialysis (PD), on the other hand, uses the body’s peritoneal membrane as a natural filter. A dialysis solution is infused into the abdominal cavity through a catheter, where it absorbs toxins and is later drained. Peritoneal dialysis can be done manually multiple times a day (Continuous Ambulatory Peritoneal Dialysis) or overnight using a machine (Automated Peritoneal Dialysis).
Each modality carries unique risks and benefits. Hemodialysis can cause complications like low blood pressure, muscle cramps, and infections at the vascular access site. Peritoneal dialysis poses risks such as peritonitis (infection of the abdominal lining), catheter-related issues, and protein loss. Hemodialysis is often recommended for patients requiring professional supervision, while peritoneal dialysis offers more flexibility and independence but demands strict adherence to hygiene.
The choice between these modalities depends on factors such as the patient’s lifestyle, health condition, and personal preferences. Both forms of dialysis significantly impact quality of life and require long-term management, but advances in technology and care are improving outcomes for patients worldwide. Ongoing research focuses on enhancing dialysis efficiency, reducing complications, and exploring alternatives like wearable artificial kidneys.
Hemodialysis
"Filtering the blood"
Hemodialysis is a common treatment for patients with end-stage kidney disease (ESKD), where a machine filters waste, toxins, and excess fluid from the blood when the kidneys can no longer function. The process involves drawing blood from the body, cleaning it through a dialyzer (artificial kidney), and returning it to the body. Typically performed three times a week at a dialysis center, each session lasts about four hours, but shorter or more frequent sessions are possible depending on individual needs. Home hemodialysis is an alternative, allowing patients to perform treatment themselves with proper training and equipment.
Hemodialysis can begin either as a planned treatment, where the patient is prepared with vascular access in advance, or acutely, often in emergency situations, for "crash-landers" who require immediate dialysis due to sudden kidney failure. In these acute cases, temporary vascular access, such as a central venous catheter, is commonly used to start treatment quickly.
Access to the bloodstream is critical for hemodialysis and is achieved through one of three main types of vascular access. An arteriovenous fistula (AVF), created surgically by connecting an artery to a vein, is the preferred option because it provides reliable blood flow, lasts longer, and has a lower risk of infection. An arteriovenous graft (AVG), which uses a synthetic tube to connect an artery and vein, is an alternative for patients whose veins are not suitable for a fistula. A central venous catheter (CVC), inserted into a large vein in the neck, chest, or groin, is typically used for short-term or emergency access but carries a higher risk of infection and clotting.
While hemodialysis is effective at sustaining life, it comes with potential risks and complications. Patients may experience low blood pressure, muscle cramps, nausea, or headaches during or after treatment. Long-term use of vascular access can lead to issues like infection, clotting, or narrowing of blood vessels. Despite these challenges, advancements in dialysis technology and individualized care have improved patient outcomes and quality of life.
The choice of where and how to perform hemodialysis, as well as the type of vascular access, depends on the patient’s overall health, lifestyle, and medical history. Ongoing research aims to enhance the efficiency and comfort of hemodialysis while minimizing risks, improving vascular access options, and exploring innovative technologies like wearable dialysis devices.
Vascular Access
Gold-standard for Dialysis
Vascular access is a critical component of hemodialysis, as it provides the pathway for blood to be drawn from the body, filtered through a dialysis machine, and returned to the bloodstream. Access types can vary based on the patient’s medical condition, treatment plan, and whether dialysis begins as a planned procedure or acutely, often referred to as "crash-landers." The three main types of vascular access are arteriovenous fistulas (AVF), arteriovenous grafts (AVG), and central venous catheters, each with unique benefits and risks.
An AV fistula is the preferred access type for long-term hemodialysis. It is created surgically by connecting an artery directly to a vein, usually in the arm. This connection strengthens the vein over time, allowing it to handle the higher blood flow needed for dialysis. AV fistulas are considered the gold standard because they provide reliable performance, have a lower risk of infection and clotting, and last longer than other access types. However, they require several weeks or months to mature before they can be used.
For patients whose veins are unsuitable for a fistula, an AV graft is a viable alternative. It involves placing a synthetic tube to connect an artery to a vein, providing a similar high blood flow for dialysis. AV grafts can be used sooner than fistulas, typically within two to three weeks after placement. However, they are more prone to complications, such as infections, clotting, or narrowing of the blood vessels.
A central venous catheter (CVC) is typically used for temporary or emergency vascular access, especially for patients who require immediate dialysis, such as those starting acutely ("crash-landers"). The catheter is inserted into a large vein, often in the neck, chest, or groin, allowing immediate access to the bloodstream. While convenient for short-term use, CVCs carry a higher risk of infection, clotting, and other complications, making them unsuitable for long-term dialysis.
The choice of vascular access depends on factors like the urgency of dialysis, the patient’s overall health, and the condition of their veins. Proper care and maintenance of the access site are essential to minimize the risks of infection and ensure long-term functionality. Complications such as infections, stenosis (narrowing of the blood vessels), or thrombosis (clotting) can compromise the access and require intervention.
Percutaneous (endovascular) arteriovenous fistula
Minimally-invasive AVF without an incision
Percutaneous (endovascular) arteriovenous fistulas (pAVF or endoAVF) are an innovative and minimally invasive approach to creating vascular access for hemodialysis. Unlike traditional surgical AV fistulas, which require open surgery to connect an artery and vein, percutaneous AV fistulas are created using endovascular techniques guided by ultrasound or X-ray imaging. This procedure is typically performed on an outpatient basis, reducing recovery time and eliminating the need for surgical incisions.
In a percutaneous AV fistula procedure, a catheter-based system is used to access the target artery and vein through small punctures in the skin. A specialized device then creates the connection between the two blood vessels using thermal energy or other advanced methods. The resulting fistula allows for increased blood flow, necessary for efficient hemodialysis, and matures over several weeks, similar to a surgically created AV fistula.
This technique offers several advantages over traditional surgery. Because it avoids incisions, there is a reduced risk of infection, less scarring, and shorter recovery times. It is particularly beneficial for patients with limited surgical options or those at high risk for surgical complications. Additionally, the procedure preserves future access sites, which is critical for patients requiring long-term dialysis.
Despite these benefits, percutaneous AV fistulas are not suitable for all patients. The success of the procedure depends on the anatomy and condition of the patient’s blood vessels, as well as the availability. Some patients may still require traditional surgical fistulas if endovascular techniques are not feasible or better kept for the future.
As a relatively new technique, percutaneous AV fistulas are supported by growing evidence of their safety, effectiveness, and long-term durability. Clinical studies suggest comparable outcomes to surgical AV fistulas in terms of patency (open and functional access) and reduced complication rates.
Advancements in catheter-based technology and imaging tools are further refining the procedure, expanding its availability and improving outcomes. As this technique becomes more widely adopted, it is expected to play an increasingly important role in providing safe, effective, and patient-centered vascular access for hemodialysis.