One of the areas with the most promising potential in nephrology is interventional nephrology. However, paradoxically, it is possibly one of the areas most historically neglected by the specialty itself. Its resurgence in recent years, although not an easy process, reflects a history that is common to the entire nephrology community. In Spain, we have not been oblivious to this process, and now it has become one of the greatest challenges in our specialty.
Diagnostic and interventional nephrology is defined as a discipline that uses imaging and interventional procedures in the kidney patient. Although these techniques were mainly developed by visionary nephrologists to fill the gap necessary in clinical practice, they were progressively introduced into other specialities such as radiology, vascular surgery, or urology, as both demand for care increased, and nephrologists lost interest in favor of other growing areas of nephrology. This aspect was evident in the different countries where interventional nephrology was practiced, from the United States to Spain (1, 2). In this way, interventionism was not prioritized within the speciality of nephrology, unlike other areas, and therefore, no training or assessment of training was dedicated to it. That is why other specialities, such as radiology or vascular surgery, had to take it on, thereby increasing their waiting list and affecting both their organizational system and nephrology itself.
In the 1990s, nephrologists’ interest in interventional nephrology began to resurface to optimize patient care. Nephrologists started to train through informal programs, mainly in the United States, thereby giving rise to variable levels of training. Doctors tried to find a standardized model of program formation, which didn't occur until the American Society of Diagnostic and Interventional Nephrology (ASDIN) was created in 2000. As procedures were carried out, the results were shown to be equal or superior to those of other specialities (3). Once again, this demonstrated nephrologists’ ability to perform procedures in various settings (4–7). However, this phase generated debates surrounding who should perform these techniques: the professionals of the specialities who were experts in the technique or the pathology specialist. In this case, the nephrologists, through their knowledge and daily work with the pathology, could capitalize on their autonomy, patient care, and waiting times, taking into account the indispensable collaboration with the specialists who have expertise in the technique.
In fact, today, most specialities have progressively begun to carry out the procedures associated with their pathologies (8). This patient-centered approach can improve the care process, resource management, and above all, innovation. This will undoubtedly redefine the borders of biotechnology with the subsequent benefit for health systems and especially, the patient. The way to bring all of this about is by creating models of academic interventional nephrology, from basic to translational science, from research to clinical research, patient centered, and multidisciplinary (9). In this context, there is inevitably an overlap with other specialities. Therefore, interventional nephrology programs should involve sharing of expertise among disciplines, namely those with which they share knowledge of the pathology, albeit from different perspectives, skills, and training.
In Spain, as a result of recognition of the need to boost interventional nephrology, the Spanish Society of Nephrology (or Sociedad Española de Nefrología [S.E.N.]) approved the creation of the Diagnostic and Interventional Nephrology Working Group in 2014 so as to promote interventional nephrology dissemination in Spain and establish and agree on the use of techniques in the speciality (10). The fundamental objective of this working group is to incorporate diagnostic procedures based on ultrasound and to recover the specific techniques required in the speciality as well as the central role that nephrologists need to play, based mainly on kidney pathology and its complications, kidney replacement therapy, and cardiovascular risk. In this way, the number of trained nephrologists would be increased, with proven training and set standards, and certification of training centers would be established.
To find out what the starting point was, the group sent out a survey in 2015 in all of the country's nephrology departments (11). Although the participation rate was not very high (35.8%), it was similar to other surveys (12) and could be considered representative of Spain, thereby allowing us to gain an overall picture of the situation.
The survey demonstrated that 30% of non-tunneled catheters were still being placed without ultrasound, despite this being recommended by the guidelines of the working group (13); that less than 30% used ultrasound in the native or transplanted kidney; and that the placement of tunneled catheters did not reach 40%. Use of ultrasound of the arteriovenous fistula (AVF) reached 56%, and that associated with the measurement of cardiovascular risk was around 20%. Ultrasound-guided native and transplanted kidney biopsies were found in 35.8% and 46% of cases, respectively. Peritoneal catheter placement was performed in 31% of the centers (Table 1) (2, 11). Thus, the implementation of interventional nephrology was heterogeneous and relatively scarce. These results are consistent with those of other countries, in which nephrologists complain of a lack of training in diagnostic and interventional techniques (2, 11). However, it was shown that all the techniques had been successfully implemented and consolidated in the training programs of several centers.
Interventional nephrology in Spain
These previous observations confirmed the need to standardize the training and procedures associated with the use of ultrasound, which is precisely on what all diagnostic and interventional procedures are based. For this reason, the working group created a consensus document specifically for ultrasound training in nephrology (14). The indisputable usefulness of POCUS (point of care ultrasound) in the vast majority of specialities and in nephrology in particular lies in its diagnostic, monitoring, and support capacity in interventional procedures. This includes the management of vascular access for hemodialysis, peritoneal catheter, measurement of cardiovascular risk, ultrasound of the urinary tract, measurement of volume with the pulmonary and cava ultrasound, parathyroid ultrasound, basic echocardiography, or AVF ultrasound-guided cannulation. In addition, it provides support for interventional procedures such as kidney biopsy and tunneled and non-tunneled catheter placement for hemodialysis and peritoneal dialysis. The aim of this document is to lay the foundations for standardizing both this training and the procedures themselves.
S.E.N. aims to establish routine practice standards, and for this purpose, a regulatory framework for both training and continuous education is required in order to make kidney patient management diligent, efficient, and comprehensive in the long term. The training program for the speciality of nephrology already establishes kidney ultrasound, kidney biopsy, and the placement of non-tunneled catheters as basic tools (15). In the new program being developed, interventional nephrology is now included among the skills to be learned. At the same time, the S.E.N. 2016−2020 strategic program (16) highlights reassessment of the speciality of nephrology as a priority, defending its competencies and developing emerging areas such as interventional nephrology.
Although interventional nephrology is now being introduced as a part of the speciality training program, its implementation, although progressive, is still slow and scarce, thereby making it necessary to develop strategies aimed at facilitating it. This means the standardization of training programs and accreditation of centers. In Spain, training programs such as the masters in diagnostic and interventional nephrology at the University of Alcalá (17) or the Parc Taulí University Hospital Vascular Access Training Program (18) have appeared. Numerous centers are beginning to standardize this training, but the curriculum also needs to be standardized. In fact, in Europe, this recognition has been obvious, as the European Commission has awarded a large grant to finance the creation of a consortium made up of 8 reference centers; 2 scientific societies, namely the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) and the Vascular Access Society (VAS); and 2 companies involved in e-learning and simulation, respectively. The aim is to set up the foundations of a pan-European curricular model in interventional nephrology: the multidisciplinary-based Nephrology Partnership for Advancing Technology in Healthcare (N-PATH) project (19).
Once we recognize that training is the bottleneck, it is as necessary for it to be standardized as it is for trainers to have expert knowledge, and at this point, it is important to recognize that the best way to move forward, as noted above, is with multidisciplinary collaboration. The technical skills of interventional radiologists and vascular surgeons acquire a fundamental value in this multidisciplinary training. The field of knowledge that the nephrologist needs is only a small part of what these specialities require, as well as being of a low level of complexity compared to the procedures performed by surgeons and radiologists. Nevertheless, it is the basis of interventional nephrology. Turning this knowledge into greater autonomy, optimization of resources, and reduction of waiting times determines an increase in efficiency and therefore, in cost. Furthermore, what can be interpreted as overlapping skills, if properly resized, still complements task distribution and can bring about not only greater efficiency but above all, can benefit the patient's well-being.
In summary, interventional nephrology is an indispensable tool in nephrology practice that has already proven its efficiency. It is slowly but surely becoming more present in our field. It has the recognition of national scientific societies, as in our case, in Spain and in Europe, which value its need and therefore standardized training. In the future, it seems necessary to be included on the curricular fellow nephrology plan, with adequate multidisciplinary training in which training programs are agreed upon and endorsed by scientific societies. Why? Because, ultimately, the nephrologist is responsible for leading multidisciplinary teams to optimize kidney patient care and promote collaboration in training and research.
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