Invasive and Innovative Nephrology

Abstract

Background: A nephrologist in the millennium offers comprehensive care to renal failure patients. Interventional nephrology plays a major role in this new approach. Overton Brooks Veterans Affairs Medical Center (OBVAMC) is the first federal health care provider in the nation offering such services. Lack of interventional radiologists and a busy surgical service has catalyzed the existence of interventional nephrology at this center. We report our early experience in successfully providing complete care to veterans with renal failure, despite multiple logistical obstacles. Method: The OBVAMC is an acute care facility providing nephrology support to hospitalized veterans and also handles access-related issues for eligible chronic dialysis patients. All procedures performed from June 2000 to September 2003 were analyzed. The procedures were performed in the cardiac catheterization laboratory or in the surgical operating rooms. Results: A total of 366 procedures were performed, which included: 110 tunneled cuffed catheter (TCC) placements, 157 temporary dual lumen catheters, 36 TCC removals, 30 fistulograms, 24 thrombectomy-/angioplasty, 1 stent placement, 3 Tenckhoff catheter placements, 3 central venograms, and 2 accessory vein ligations. Bleeding from the exit site of a TCC in one patient was the only complication encountered. Conclusion: Interventional nephrology experience at OBVAMC has been very encouraging and has succeeded in providing optimal care to the veterans. Interventional nephrology programs can be developed in any tertiary care hospital.

• interventional nephrology
• cuffed tunneled catheter
• dialysis access

INTRODUCTION

Interventional nephrology is an emerging subspecialty of nephrology. It encompasses procedures involving placement and maintenance of dialysis access. The nephrologist of the last century was dependent on specialists from various other fields to assist in the optimal care of renal failure patients, which often lead to delays. The nephrologist of the present era not only has to be efficient in diagnosing and treating the patient with kidney disease, but also has to provide prompt and effective therapy to maintain a proper standard of care and keep the financial burden low. In 2000, in the United States, the American Society of Diagnostic and Interventional Nephrology[1] was formed precisely to impress upon nephrologists the need to change their view about the practice of nephrology. The society promotes the procedural aspect of nephrology. The modern nephrologist is trained to provide a unique “one-stop, one-shop” service with expertise in maintaining the “life-line,” i.e., the arteriovenous access for hemodialysis. Nephrologists in selected centers in the United States are now safely performing various endovascular procedures.[2-5]

The Overton Brooks Veterans Affairs Medical Center (OBVAMC) in Shreveport, Louisiana, is the first federal health facility, as far as we know, in the entire nation to start this trend. The interventional nephrology service was established here in late 2000. This article reports our 3-year experience in starting such a service and the obstacles we faced along the way. We have succeeded in providing a complete care package to the veterans in and around Shreveport, Louisiana.

METHOD

The OBVAMC serves a population of over 131,000 veterans residing within its primary service area, whichencompasses 15 northeast Texas counties, five southwestern Arkansas counties, and 12 northwest Louisiana parishes. The nephrology service is responsible for providing both acute and chronic renal replacement programs. The dialysis unit was established in 1987 and has since grown to a five-bed unit, providing dialysis service only to the hospitalized veterans. The chronic maintenance dialysis is contracted out to various agencies in the community. The chronic renal failure patients receive their dialysis access related care at our hospital. We follow 60 chronic hemodialysis and four peritoneal dialysis patients. All procedures performed from June 2000 to September 2003 were analyzed. The procedures were performed in the cardiac catheterization laboratory or in the surgical operating rooms.

VASCULAR ACCESS

Maintenance hemodialysis is performed using reliable vascular access, which is achieved via a cuffed or noncuffed catheter placed in the central vein, arteriovenous fistula (AVF), or an arteriovenous graft (AVG).[5&6] A noncuffed catheter is generally used in an emergency situation.

A tunneled cuffed catheter (TCC) is the bridging device placed in the central vein before a surgeon creates a permanent arteriovenous (AV) access using either native vessels or an artificial polytetrafluoroethylene (PTFE) graft. Commonly encountered complications with TCC are poor blood flows and infection, and, hence, it is not a preferred dialysis access for long-term use. But timely placement of TCC is important to initiate dialysis therapy in renal failure patients without a permanent AV access.

A properly functioning vascular access is vital for providing adequate hemodialysis. The placement of a permanent vascular access does not resolve all the problems since complications like stenosis and thrombosis leading to access failure are frequently encountered. Timely monitoring and intervention by an interventional nephrologist can frequently salvage these accesses.[7&8]

A minimum of 2–3 weeks for PTFE graft and 6–12 weeks for a native AV fistula is necessary for dialysis access maturation. The TCC functions as an alternate dialysis access during the interim period. Common problems associated with the permanent AV access include clotting of the dialysis access, stenosis at the anastomotic sites, poor maturation of the native AV access, and central venous stenosis. Thromboangioplasty is the procedure involving declotting of a thrombosed AV access and subsequent angioplasty of any stenotic segment to prevent recurrence.

INTERVENTIONAL NEPHROLOGY TRAINING

The authors underwent formal 6-month fellowship training in interventional nephrology at the affiliated University Hospital after they had completed their regular nephrology training. Interventional nephrology training included hands-on experience with trained nephrologists on all the procedures along with didactic lectures and close interactions with surgeons to better understand the surgical techniques involved in AV graft/fistula placement. The training concluded in achieving an accreditation certificate as per guidelines from the American Society of Diagnostic and Interventional Nephrology.

PROCEDURES

A tunneled cuffed catheter (TCC) preferably is placed in the right internal jugular vein for the flow dynamic suitability for adequate dialysis. The internal jugular vein is accessed with ultrasound guidance and a micropuncture needle (21 gauge). The guide wire is then introduced through this needle and the tract is serially dilated with fluoroscopic guidance. The TCC is tunneled under the skin and over the clavicle to an exit site in the pectoral region. The TCC is then introduced over the guide wire to position its tip in the right atrium.

Endovascular procedures include: fistulograms to evaluate poorly maturing fistulas by injecting radio-contrast material; thrombo-angioplasty, which involves establishing an access into a thrombosed dialysis access followed by removal of the clot using either a MTI™ pulse-spray catheter or sophisticated devices like Angiojet™ catheters. Then by using radiocontrast material, the stenotic lesions are identified and dilated with a balloon to prevent recurrence. Occasionally a stent is deployed for elastic stenotic lesions. The central veins are then visualized with additional radiocontrast material for a possible subclinical central occlusion.

OUR EXPERIENCE

At OBVAMC we do not have the support of interventional radiology and the surgical service has other major procedures to prioritize over dialysis access problems. Most end stage renal failure patients were referred to the affiliated University Hospital for both cuffed tunnel catheter placement and declotting of permanent dialysis access, causing inconvenience to the veterans and adding significantly to the budget of the OBVAMC. We have successfully developed aninterventional nephrology program for placement of cuffed tunneled hemodialysis catheters, declotting, angiography, and angioplasty of arteriovenous dialysis accesses and placement of Tenckhoff peritoneal dialysis catheters. The unique situation of OBVAMC, the understaffed and overworked surgical service, lack of interventional radiology services, and the costly referral process worked to our advantage in establishing interventional nephrology service. A total of 366 procedures were performed (Table 1). There were no selection criteria for performing these procedures. All procedures were performed for standard indications as practiced in nephrology. The noncuffed catheters were placed mainly in the dialysis unit without sedating the patients.

Table 1 List of procedures

TCC–placement	110
TCC–removal	36
Thromboangioplasty	24
Fistulograms	30
Stent placement	1
Central venograms	3
Tenckhoff catheter	3
Noncuffed catheters	157
TOTAL	366

The endovascular procedures are performed in the cardiac catheterization laboratory (CCL). The peritoneal dialysis catheters are placed using the surgical operating room. The biggest issue is scheduling procedures in the CCL considering the constantly increasing incidence of acute coronary events. The CCL was shut down in the later half of 2002 for upgrading the equipment and major renovations creating a crunch for providing these services. The hospital administration provided adequate time in the surgical operating rooms to help us with the program. The problems encountered in the surgical operating room were unique and unexpected. Firstly, the lack of proper fluoroscopy beds posed problems of poor visualization on the monitor and at times even near-blind conditions. Secondly, lack of proper digital subtraction imaging forced us to withhold our complex cases. The advantage of the operating room was that we had trained certified registered nurse-anesthesiologist to provide and monitor conscious sedation during the procedure.

The Tenckhoff catheter placement is dictated by the dialysis modality selected by the patient. Hemodialysis remains a preferred modality in the United States and our center is no different. The ASDIN guideline specifies a minimum number of Tenckhoff catheter placements per year to maintain the skill and certainly would be a limiting factor if less than five catheters are placed per year.[9]

COMPLICATIONS

The complications reported in literature are very low when an interventional nephrologist performs these procedures as compared to radiologists or surgeons. The complications included minor oozing from the exit site (0.36%) and a very low incidence of pneumothorax (0.06%) with TCC placement. Similarly, the incidence of hematomas and ruptures of dialysis access during endovascular procedures has been significantly lower with interventional nephrologists.[10] Hence, not surprisingly, the only complication encountered during this period was bleeding from an exit site 12 hours postplacement of TCC, which was managed conservatively with local compression, intravenous desmopressin acetate, and a transfusion of 2 units of packed red blood cells. Infection related to the procedure per se (within the first week after placement) was not seen in any of the procedures performed. Eight TCC were removed at varying intervals of 8 weeks to 1 year, for either bacteremia or persistent exit site infection. There were no life threatening complications like rupture of major vessels or pneumothorax encountered during this period.

Despite these difficult issues we have continued to pursue our goal and managed to provide the required services as a challenge. Our experience in interventional nephrology at OBVAMC has been very encouraging and we have succeeded in providing near-optimal care if not complete care to the veterans. As a result of this program the hospital has saved close to $500,000 over a short period of time.[11&12] Interventional nephrology programs can be developed in any tertiary care hospital and with experience they are bound to improve the quality of care further.