|Year : 2021 | Volume
| Issue : 1 | Page : 1-5
Interventional nephrology: A review of literature
Abdul Rashid Ahangar, Suresh Chandra Tiwari, Sanjeev Gulati
Department of Nephrology, Fortis Flt. Lt. Rajan Dhall Hospital, Vasant Kunj, New Delhi, India
|Date of Submission||01-Jun-2020|
|Date of Decision||18-Nov-2020|
|Date of Acceptance||25-Nov-2020|
|Date of Web Publication||29-May-2021|
Dr. Abdul Rashid Ahangar
Department of Nephrology, Fortis Flt. Lt. Rajan Dhall Hospital, Vasant Kunj, New Delhi 110070
Source of Support: None, Conflict of Interest: None
Interventional nephrology (IN) is one of the prominent nephrology fields that mainly copes with the diagnosis and treatment of patients with renal failure by using special techniques, such as ultrasonography of kidneys, performance of kidney biopsy, insertion of peritoneal dialysis catheters, tunneled dialysis catheters, and maintenance of vascular access for patients receiving hemodialysis. The IN also deals with performing percutaneous endovascular procedures to maintain arteriovenous fistulas or grafts that are functional in patients with renal failure. When performed by a variety of experts, all these procedures resulted in delays in diagnosis and treatment. This led to the formation of a team of nephrologists who started performing these procedures themselves. They opened training centers and provided training to other nephrologists. Excellent results were obtained when these procedures were performed by nephrologists. The IN has ensured to provide renal care with effectiveness, safety, and reduced costs. There is a need to develop awareness among the people, so that these procedures can be performed in an outpatient setting with lower costs. Nephrologists should get adequate training to develop necessary skills to provide standard renal care.
Keywords: Hemodialysis catheters, interventional nephrology, vascular access
|How to cite this article:|
Ahangar AR, Tiwari SC, Gulati S. Interventional nephrology: A review of literature. J Health Res Rev 2021;8:1-5
| Introduction|| |
Interventional nephrology (IN) is one of the prominent nephrology fields that deals with procedures in patients with renal failure. Interventional nephrology can be traced back to the mid-1980s when a nephrologist, Gerald Beathard from the United States faced challenges in providing effective care of vascular access to his patients with end-stage renal disease (ESRD), which resulted in a delay in the diagnosis, initiation, and continuation of treatment in a timely manner. Then, he himself started training people and prepared his own team to perform angiograms and all forms of endovascular procedures that were essential to deliver and maintain good care for patients with renal failure. Since then, Dr. Beathard along with other nephrologists put in all of their effort and have trained hundreds of nephrologists in academic programs and have sufficient infrastructure to provide access centers across the country. There was an apprise in IN with an objective to address discrepancies that existed in nephrology care. Although initially they faced several challenges from specialists who used to perform these procedures traditionally, at the starting of the 21st century this group of physicians remain motivated, which led to the formation of the American Society of Diagnostic and Interventional Nephrology (ASDIN). Also, this branch of nephrology known as IN has gained immense popularity and is widely accepted in the world of nephrology. The practice of IN has been monitored from time to time since the beginning to have proper training programs and for maintaining quality standards.
The ability to diagnose and treat patients with renal failure requires a comprehensive approach that necessitates the use of special techniques, such as ultrasonography, performance of kidney biopsy, placement of a peritoneal dialysis (PD) catheter, and maintenance of vascular access for hemodialysis.
| Renal Ultrasonography|| |
Renal ultrasonography plays a fundamental role in percutaneous renal biopsy, insertion of hemodialysis catheters, preoperative vein mapping, and evaluation of arteriovenous grafts and fistulas. It is a very useful technique in the evaluation of chronic renal failure, thereby avoiding further unnecessary evaluation and biopsy., However, formal training in ultrasonography is not very commonly included in nephrology training programs. Nephrologists use sonography as an effective modality to improve patient care. This further increases patient convenience, expedites patient care, and provides improved understanding and better interpretation.
Patient’s evaluation and physician’s efficiency can be enhanced by including ultrasonography into nephrology practices. In an outpatient setting, delays associated with scheduling ultrasonography and obtaining results can be avoided because the sonogram can be performed and interpreted during the patient’s visit [Figure 1]. This improves patient care and satisfaction by reducing the waiting time, multiple visits to different centers, or minimizing the need of additional testing and hospital admissions. A significant reduction in time to perform renal ultrasonography from 46.5 days to 4.7 days in an outpatient setting has been observed in the data collected from an academic center of the United States when performed by a nephrologist.
|Figure 1: (a) The technique of a real-time ultrasound kidney biopsy performed by an operator. (b) Image of kidney ultrasound with a biopsy needle located at the lower pole of the kidney.|
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Renal ultrasonography is a relatively easy skill to acquire, but very few nephrology programs provide thorough training in ultrasonography. In a survey of renal fellowship program, it was observed that only 8% of the programs included diagnostic ultrasonography and 42% included ultrasound guidance for kidney biopsies without the help of a radiologist. The skill to perform this procedure with nephrologists is limited, and there is a need to increase the number of trained physicians and include ultrasonography in nephrology training programs to make this an integral part of nephrology practice.
| Insertion of Peritoneal Dialysis Catheters|| |
Peritoneal dialysis was first introduced in 1959 by Richard Ruben when he used this technique in a patient with ESRD. Later, several other techniques such as open surgical approach, percutaneous laparoscopy also called peritoneoscopy, were introduced for the insertion of the PD catheter into the abdominal cavity [Figure 2].
|Figure 2: (a) Spot film demonstrating free flow of contrast injection into the peritoneal cavity. (b) Spot film showing a peel-away sheath in place during insertion of a Tenckhoff catheter. (c) Spot film showing appropriate placement of a Tenckhoff catheter.|
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There are several advantages of PD, including preservation of residual renal function, improved fluid and blood pressure control, reduced incidence of left ventricular hypertrophy, less chances of severe cardiac arrhythmias, and improved quality of life, as these increase patient mobility and independence. Initially, very few patients with ESRD choose to use PD. This could be due to improper insertion or delay in placing the peritoneal catheter by surgeons. The utilization of PD has increased over a period of time, and more number of patients started receiving PD over hemodialysis by using open surgery or laparoscopy because of good results and safety. The success of the PD catheter insertion depends on the proper placement of catheters. Therefore, it is important that the insertion of PD is performed by nephrologists.
Complications after PD catheter placement can occur within or after 30 days of the surgical procedure. A systematic review and meta-analysis revealed similar outcomes of open surgically and laparoscopically placed PD catheters, with no difference in the early complication rate. Higher one-year catheter survival and less migration occurred more in the laparoscopic insertion technique. Peritonitis was similar in both the groups. This suggests that laparoscopic placement of a PD catheter leads to higher patient comfort, lower hospital cost, and better functioning than the open procedure.
| Vascular Access for Hemodialysis|| |
Vascular access can be of three major types, namely arteriovenous fistula (AVF), arteriovenous graft (AVG), and tunneled dialysis catheters (TDCs). The need for vascular access in renally impaired patients can be temporary or permanent and can range between several hours for a single dialysis to months. The non-tunneled central vein catheters (CVCs) do not hold much importance because of their use as temporary access. The construction of a permanent vascular access allows repeated angio access for months to years and delivers an adequate flow for the dialysis as per the requirement.,
The AVF plays a major role in connecting an artery and a vein through surgery, usually in the non-dominant arm of the patient. The AVG is also similar to AVF, which connects an artery and a vein by using an artificial tube [Figure 3]. Vascular access using AVF is considered the preferred option for dialysis, as it has the highest long-term patency rates with lowest morbidity and mortality rates. It usually takes at least two months for AVF to mature for optimal dialysis.
|Figure 3: The two most common types of AV grafts. (a) The straight graft between the radial artery and basilic vein. (b) The loop graft between the brachial artery and basilic vein.|
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The TDC, a cuffed double-lumen silicone elastomer catheter or a pair of cuffed single-lumen catheters, is placed into an internal jugular vein for permanent access and acts as a channel to AVF dialysis [Figure 4]. It is suggested by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) that <10% of patients who are receiving chronic maintenance hemodialysis can be maintained on catheters as their permanent dialysis access.
|Figure 4: Access to the right internal jugular vein guided by real-time ultrasound. The catheter has been tunnelized from the upper part of the chest to the internal jugular site.|
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The TDC is used in certain clinical situations when there is a lack of availability of suitable vessels for AVF or there is an inability to use fistulae because of certain complications, including thrombosis and bleeding. Traditionally, TDCs were inserted by vascular surgeons and radiologists. Over a period of time, nephrologists have started performing these procedures, with a higher rate of success. Nephrologists also perform other activities such as undertaking catheter exchange, removal and repairing their function by administering thrombolytic agents at the time of catheter blockade.
Although AVF is the preferred option for access in patients initiating hemodialysis, the use of AV grafts in the United States is uneven and there is an increased dependence on central venous catheters. With the release of the KDOQI guidelines and combined efforts of interventionalists, surgeons, and general nephrologists, the prevalence of AVF has increased whereas the prevalence of AVG has declined. Guidelines developed by NKF-KDOQI promote the increased construction of AVF and the early referral of patients to nephrologists. This will provide timely construction of AVF or AVG fistula, so that the use of venous catheter access could be minimized.
| Percutaneous Endovascular Procedures|| |
Vascular stenosis is a frequent complication in vascular access. Other complications include infection and thrombosis. These complications, when put together, negatively affect patient outcomes. To prevent these outcomes, dialysis access often requires surgical or endovascular intervention to promote maturation of graft and avoid or manage occlusion. Data have shown that 10% to 25% of AVFs do not mature properly and fail to sustain dialysis therapy. This is referred to as primary failure. The reason for early failure could be the development of stenosis in a venous channel or a secondary vein taking blood out of AVF. Stenosis could be managed by using a percutaneous angioplasty balloon and it is performed by trained nephrologists. The development of catheters has allowed the use of endovascular procedures to maintain naive AVF functions. Thrombosis in majority of the cases is mainly caused due to stenosis; it is recommended to check the vascular access at defined regular intervals for the early detection of early stenosis and to prevent thrombosis by mechanical or pharmaco-mechanical procedures in an outpatient setting performed by nephrologists.,,
Interventional nephrology has several advantages, such as prompt availability of health-care facilities, especially for patients who need care for vascular access. With the traditional approach adopted in patients with vascular access care, there has been a delay in the rectification of AV access dysfunction or failure as it is important to first treat the complications that arise from the vascular access (VA) procedure., It is not easy for patients with dysfunctional VA to get an immediate intervention due to issues in appointment with their nephrologists. This can cause delay in managing complications and dialysis treatment. However, with IN services these issues can be taken care of within the same day or not more than 24h. This resulted in increased focus on patients with ESRD, increased patient satisfaction, and improvement in medical care. In patients receiving dialysis, patients have complications that are sometimes beyond the scope of other specialists who interact with them. There are certain situations when the specialist has to assess and arrange emergency dialysis, balancing the concentration of acid–base and electrolytes, dose of drug, and follow-up of access outcome after the procedure is completed. It is not expected that other specialists can take care of any such situation. However, on the other hand, for a nephrologist this is a step-by-step procedure that is easy to monitor and at the same time this also assures the patient that the operator is skilled to perform the procedure and it also brings some amount of satisfaction to the patient. In any surgical procedure, there is a chance that medical errors can occur and if IN is involved in the renal care then there is a possibility of getting the information transferred to the people who are involved in the care of the patient. The IN also helps in bridging the communication gap between patients and care providers. This results in reducing the inaccuracies and medical errors that can occur in improper handling of the procedure.
In performing a procedure such as dialysis, there are so many factors that specialists must take into account. These factors include past medical history of the patient, access history of the patient, the potential next access, and the insertion of a PD catheter. All these aspects are important to consider but are often neglected in clinical practice where patients do not get enough time to spend with the specialist. This can be overcome by using IN, as it takes everything into consideration and provides an individualized approach to VA. For example, in a patient who had an access failure or improper placement of a PD catheter given that VA is not an option and has a less success rate, the specialist should consider using secondary AVF.
Although VA has been used since the mid-1960s, this area needs further research. There are a lot of questions that still need to be answered, such as predictability and improvement in maturation of an AVF, prevention of failure of AV access, and reduction of the occurrence of complications arising due to catheters.
A recent study has shown better VA outcomes, such as shorter hospital stays and missed VA-related outpatient dialysis treatments after initiation of IN programs., These programs have also resulted in improved patient satisfaction and reduced costs of VA care., The cooperation and collaboration between nephrologists, radiologists, and vascular surgeons is needed to improve the medical treatment and patient’s adherence.
In conclusion, patients with renal failure need frequent interventional procedures. Interventional nephrology provides an excellent opportunity to nephrologists to get trained in this domain and to develop expertise that is required to perform the interventions. There is also a need to take the initiatives to promote such training programs so that more and more people can be made aware of it and patients could receive benefit from such programs.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]