In recent years, nephrologists have taken the initiative of performing nephrology-related procedures themselves. Because of their unique clinical perspective on renal patients and better understanding of the intricacies of renal replacement therapy, nephrologists are ideally suited for this activity. This approach has minimized delays in medical care and decreased the number of hospitalizations and their lengths of stay, thereby improving care, decreasing costs, and increasing patient convenience.
Interventions commonly used by nephrologists include renal ultrasonography and biopsy, peritoneal dialysis catheter-related procedures, vascular access education, vascular mapping, percutaneous balloon angioplasty, thrombectomy, intravascular coil and stent insertion, and tunneled hemodialysis catheter-related procedures. Although the performance of these procedures by nephrologists offers many advantages, appropriate training in order to develop the necessary procedural skills is critical. Recent data have shown that a nephrologist can be successfully trained as a competent interventionalist. In addition to their documentation of excellent outcome data, multiple reports have shown the safety and success of a nephrocentric interventional approach.
The last decade has represented a period of significant advances in this new field. This has been driven in part by the formation of the American Society of Diagnostic and Interventional Nephrology whose mission includes training, quality assurance, and certification. Recently, this body has published guidelines (http://www.asdin.org) for training in nephrology-related procedures, and it has begun certifying physicians in specific procedures related to CKD. The society anticipates that these complementary approaches will promote the skillful conduct of these procedures by nephrologists, with consequent and significant augmentation of total renal care. Accordingly, challenges for the future include an awareness of this burgeoning subspecialty and the development of larger-scale training programs within academic centers.
Although peritoneal dialysis catheter insertion and renal ultrasonography are important components of interventional nephrology, endovascular procedures for vascular access dysfunction form the backbone of this specialty. Vascular access always has been the Achilles' heel of extracorporeal dialysis. Historically, nephrologists took the lead in the development and clinical application of innovations in vascular access. However, surgeons and radiologists have become the clinicians who perform most vascular access-related procedures, perhaps by default. As a result, the vascular access options available to nephrologists who care for hemodialysis patients have typically been limited by the diagnostic and percutaneous technologies offered by their radiology colleagues and the repertoire of their surgical colleagues.
Now, the therapeutic landscape is changing in those medical communities in which interventional nephrology has emerged and broadened the diagnostic and procedural horizons available to nephrologists and thus their patients. As one might anticipate, the downstream effect of all of this is a resurgence of the assumption of nephrologic leadership and advocacy for clinical decision-making in vascular access planning, construction, and maintenance. At many academic medical centers, there is passionate enthusiasm for education in vascular access that extends from the senior to the junior faculty to nephrology fellows. This excitement has generated a commitment to access surveillance, management, and maintenance. In this context, vascular access care is moving from an episodic event to coordinated patient care.
These changes have resulted from the direct involvement of interventional nephrologists in patient care, collaborating with other physicians and other members of the health care team. De novo ESRD patients are now more expeditiously examined for purposes of access planning. Prevalent clinical problems in hemodialysis patients such as reduced access flow rates, swollen arms, and symptoms of hand ischemia are assessed on a regular basis in the dialysis clinics. Physical examination techniques are shown and, whenever possible, correlated with vascular radiographic images. Results of diagnostic and therapeutic interventions are shared with the patient's care team through reports and direct communication.
To nurture and expand the domain of interventional nephrology, this issue of Advances in Chronic Kidney Diseases is dedicated to disseminating the knowledge of this rebirthed nephrologic subspecialty to academic nephrology faculty, practicing nephrologists, and fellows-in-training. The topics have been carefully vetted to best convey the breadth and depth of interventional nephrology in succinct fashion.
Sachdeva and Abreo provide an account of the history of interventional nephrology in the United States. They emphasize that physicians who were caring for renal patients also performed many of the nephrology-related procedures in the 1960s and 1970s. Indeed, some of the fundamental elements of a hemodialysis access (ie, an arteriovenous fistula creation) were created by kidney doctors. To wit, interventional nephrology can be viewed as a resurrection and refinement of several procedures previously performed by us! These authors additionally point out that the emergence of interventional nephrology in the United States has evolved out of the need to improve patient care and reduce the pressures placed on our radiological and surgical colleagues by the increased procedural demands of patients with ESRD. Notably, interventional nephrology is not just a national phenomenon. It has successfully migrated to other countries. Herrara-Felix and Orias attest to this and relate the benefits derived therefrom.
Based on the complications, morbidity, mortality, and costs of medical care, the arteriovenous fistula remains the best available form of arteriovenous access. For this reason, the “Fistula First” initiative and NKF KDOQI vascular guidelines have stressed the increased frequency of construction of this type of hemodialysis access. One of the most important strategies to increase fistula prevalence is pre-operative vessel mapping, and, in this issue, Wasse and Niyyar highlight a variety of mapping techniques and underscore the impact of vessel mapping on arteriovenous fistula creation. Moreover, there is now multilateral fistula creation by nephrologists in the United States and other countries including Pakistan, India, Italy, Germany, Slovenia, and Poland. However, it is only recently that a nephrologist, Dr Mishler, has initiated a program of fistula creation by nephrologists, which he describes in this issue. The adoption of his success may extrapolate to a reduction in hemodialysis catheter prevalence and infections, with a consequent increase in fistula rates.
Vascular access stenosis continues to be a major cause of access dysfunction and thrombosis. Recent information has emphasized that neointimal hyperplasia is the main culprit that leads to access failure. Also, endothelial injury plays a major role in the pathogenesis of neointimal hyperplasia and balloon-induced damage during percutaneous transluminal balloon angioplasty (PTA) is undesirable. Despite this, fistula failure is a major issue that requires the application of invasive strategies such as PTA. In the current issue, Lee and Roy-Chaudhury sheds light on the pathophysiology of neointimal hyperplasia and focuses on advances in the therapeutic options to halt cellular proliferation, while Beathard provides a detailed account of invasive interventions to successfully salvage failed fistulas, thereby precluding early, traditional abandonment of the fistula, its conversion to an arteriovenous graft, or de novo fistula creation at another site.
Hand ischemia is a morbid complication of an arteriovenous access and can lead to not only hand pain but tissue necrosis, with the loss of digits and even amputation. Early diagnosis and prompt intervention play a major role in the management of patients with hand ischemia. Recently, interventional nephrologists have focused their attention on this important complication of an arteriovenous access. The report by Salman and colleagues describes the pathophysiology of hand ischemia and provides up-to-date information on the management of this complication.
In addition to PTA, endovascular stents are used as a treatment of peripheral as well as central stenotic lesions. In this issue, Yevzlin and Agarwal provide an excellent account of central venous stenosis and its treatment by stenting. Finally, the current issue provides information on a variety of additional procedures included under the domain of interventional nephrology. Renal ultrasonography is one of these, and Gosmanova emphasizes that this technique can be facilely used at the bedside to optimize diagnosis and therapy. Lastly, tunneled hemodialysis and peritoneal dialysis catheter–related procedures are also now within the jurisdictions of many interventional nephrologists, and Alvarez and Chan provide a detailed account of advances in these areas.
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