Outcomes of cephalic arch stenosis with and without stent placement after percutaneous balloon angioplasty in hemodialysis patients.

Cephalic arch stenosis is a common complication in maintenance hemodialysis (MHD) patients with brachial artery-cephalic vein fistulas and frequently leads to loss of the functioning brachial artery-cephalic vein fistula. There is paucity of conclusive data to guide appropriate management. We examined the risk of recurrence of cephalic arch stenosis after angioplasty compared to angioplasty after stent placement determined by angiography of the involved upper extremity over time in a contemporary cohort of MHD patients treated in two interventional nephrology practices from March 2008 through May 2011. We retrospectively identified 45 MHD patients with evidence of cephalic arch stenosis (age 60 ± 30 years, 45% men) on elective angiograms. The median number of days until another angioplasty was required decreased, starting with a median of 91.5 days after the first, 70.5 days after the second, 85 days after the third, and 56 days after the fourth. Angioplasty is associated with a faster rate of recurrence of cephalic arch stenosis. The placement of intravascular stent seems to prolong the patency compared to angioplasty alone. Clinical trials with a larger sample size will better elucidate the value and timing of angioplasty versus stent placement in cephalic arch stenosis.

Timing of secondary arteriovenous fistula creation avoids tunneled catheter placement.

The concept of secondary arteriovenous fistula, though not novel, is seldom practiced for lack of initiative or hesitancy in deciding the appropriate timing to abandon the existing access. We report a case illustrating the benefits of implementing the strategy in an elderly diabetic dialysis patient, successfully avoiding a tunneled cuffed catheter placement.

New tunneled hemodialysis catheter placement through the old exit site.

Accidental loss of tunneled hemodialysis catheters has been observed in chronic hemodialysis patients. Although a new catheter could be inserted using a fresh site, catheter insertion can also be accomplished by utilizing the existing exit site. In this analysis, we report 10 cases of an extruded tunneled hemodialysis catheter. The catheters had been in place for 2-6 months. The time elapsed after catheter extrusion ranged from 6 to 72 hours. None of the patients demonstrated any evidence of exit site or tunnel infection. Patient age ranged from 45 to 77 years. Diabetes mellitus was the cause of renal failure in 40% of the cases. Catheter insertion was accomplished by inserting a guidewire into the exit site and navigating it through the tunnel to the central venous system and into the right atrium. A diagnostic catheter was then navigated over the wire and contrast study performed to confirm the position. The wire was reinserted and a new tunneled hemodialysis catheter fed over the wire and into the atrium. Nine catheters were successfully placed using this technique. One patient had nausea and hiccups upon wire insertion into the atrium. There were no hemodynamic consequences. The wire was removed and a new catheter inserted on the other side using the left internal jugular vein. All of the catheters inserted using this technique functioned appropriately. There were no exit site or tunnel infections for up to 4 weeks' follow-up. We conclude that patients with catheter extrusion can receive a new catheter through the existing exit site, tunnel, and venotomy.

Aging veterans and the end-stage renal disease management dilemma in the millennium.

The population of aging veterans with complex multiple medical problems is increasing steadily in developed nations. The life expectancy in an aging population with end-stage renal disease (ESRD) is often compared with terminal malignancy. Renal failure in elderly patients often generates a myriad of complicated issues and the nephrologists are faced with the dilemma of conveying the prognosis of renal failure in elderly patients and also explain the pros and cons of offering a renal replacement therapy. Our objectives were to assess the cumulative survival in veterans with ESRD over 70 years of age and to evaluate the factors considered for either not initiating or withdrawing from dialysis. All veterans above age 70 years, who were being evaluated for possible dialysis therapy over a 5-year period, were included in the study. The cumulative survival rates at 1 year, 3 years and 5 years were 60%, 37%, and 20%, respectively. Tunneled cuffed catheter was the dialysis access in a third of these patients on dialysis adding to the morbidity. Twenty-four patients considered either not initiating or withdrawing from dialysis therapy after consensus agreement from either the patient or the power of attorney. The decision to initiate dialysis therapy should be made considering the social, ethical, and associated comorbid conditions. A decision to not initiate or withdraw dialysis is possible in critically ill elderly patients and if taken judiciously can reduce physical and mental stress of both the patient and their family members.

Interventional nephrology in a federal hospital: economics of health care.

Interventional nephrology is now an accepted subspecialty of nephrology that is revolutionizing the standard of care for renal failure patients. Interventional nephrology deals with the placement of tunneled cuffed catheters (TCCs) and maintenance of permanent vascular accesses, thus assisting in timely care. Prior to 2000 most end-stage renal disease (ESRD) patients from the Overton Brooks Veterans Affairs Medical Center (OBVAMC) were referred to an outlying hospital for TCC placement and endovascular procedures (EVPs) of permanent dialysis access. The referral process was cumbersome for the patients and expensive to the Medicine Service. OBVAMC started an interventional nephrology service in 2000. The current study reports the financial benefits of starting an interventional nephrology service at our institution. All procedures performed during the period from April 2000 to April 2004 were analyzed. The procedures were performed in the cardiac catheterization laboratory. The total payment (physician's and hospital fees) to the referral hospital for procedures prior to April 2000 was used to estimate the average savings to the Medicine Service over the last 4 years. A total of 129 TCCs and 43 EVPs were performed during this period. The estimated expense to OBVAMC would have been US dollars 603,978 for TCCs and US dollars 288,100 for EVPs based on charges prior to April 2000. The actual expense to the hospital, including facility fees and disposables, was US dollars 156,013. The net savings to OBVAMC over the last 4 years was US dollars 736,065. Interventional nephrology provided to a small population of renal failure patients in a tertiary federal health care facility has resulted in huge savings for the hospital. Increasing awareness of this procedural aspect of nephrology benefits not only the patients, but also helps ease the financial burden of ever-escalating health care costs.

Invasive and innovative nephrology.

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.

Does treating obesity stabilize chronic kidney disease?

BACKGROUND: Obesity is a growing health issue in the Western world. Obesity, as part of the metabolic syndrome adds to the morbidity and mortality. The incidence of diabetes and hypertension, two primary etiological factors for chronic renal failure, is significantly higher with obesity. We report a case with morbid obesity whose renal function was stabilized with aggressive management of his obesity. CASE REPORT: A 43-year old morbidly obese Caucasian male was referred for evaluation of his chronic renal failure. He had been hypertensive with well controlled blood pressure with a body mass index of 46 and a baseline serum creatinine of 4.3 mg/dl (estimated glomerular filtration rate of 16 ml/min). He had failed all conservative attempts at weight reduction and hence was referred for a gastric by-pass surgery. Following the bariatric surgery he had approximately 90 lbs. weight loss over 8-months and his serum creatinine stabilized to 4.0 mg/dl. CONCLUSION: Obesity appears to be an independent risk factor for renal failure. Targeting obesity is beneficial not only for better control of hypertension and diabetes, but also possibly helps stabilization of chronic kidney failure.

Fluoroscopy-assisted placement of peritoneal dialysis catheters by nephrologists.

In the early 1950s and 1960s, peritoneal dialysis (PD) was used primarily to treat patients with acute renal failure. Continuous ambulatory peritoneal dialysis (CAPD) was introduced in 1976 and continues to gain popularity as an effective method of renal replacement therapy for patients with end-stage renal disease (ESRD). The PD catheter is inserted into the abdominal cavity either by a surgeon, interventional radiologist, or nephrologist. We have adopted a percutaneous approach with fluoroscopic guidance for PD catheter insertion that is easy, safe, and provides good patency and infection rate results. In this article we describe the technique and our results. From August 2000 to May 2003, 34 PD catheters out of 36 were successfully inserted using the percutaneous fluoroscopic technique in selected patients referred from the nephrology clinic. All the PD catheters were placed in our Interventional Nephrology Vascular Suite by nephrologists.

Post transplant lymphocele: a single centre experience.

The occurrence of post renal transplant lymphocele is variable and the best approach to treatment is not well defined. The purpose of this study was to find out the incidence of post transplant lymphocele at our centre, identify demographic or surgical factors that may have influenced lymphocele formation, and distinguish the best approach to treatment. The charts of 138 consecutive renal transplant recipients from 1996 to 2001 were retrospectively reviewed. The demographic characteristics, comorbid illnesses, occurrence of lymphocele and its treatment modality were recorded. A total of 36 (26%) patients developed lymphoceles. There was a significant relationship between an increased body mass index (BMI) and lymphocele occurrence (P > 0.01). The recurrence rate with drainage alone was 33%, which decreased to 25% with sclerotherapy. In comparison, both laparoscopic and open surgical marsupialization had a much lower but similar recurrence rate of 12%. The laparoscopic method had less morbidity, a shortened hospital stay, and less infection than open surgery.

Support vector machine for determining dose of dialysis.

Calculation of dose of haemodialysis using blood-based modelling is subject to controversies as it is based on unrealistic assumptions. This paper proposes the use of dialysate-based modelling by SVMs to calculate the delivered dose of dialysis. The authors use the solute removal index (SRI), which is correlated to the amount of urea removed, for calculating the dose. The SVM model was trained to recognise the evolution of weight, blood urea nitrogen concentration and solute removal index with respect to time and then used to predict the solute removal index. When the estimated SRI values were compared to the actual SRI values determined by the standard method, the prediction errors were small. This paper is the first demonstration that SVM regression can predict delivered dose of haemodialysis with a clinically acceptable accuracy. The result is an effective technique that will offer the physician a better guide to the monitoring and prescription of haemodialysis therapy thereby reducing the mortality rate among patients.

Blood flow surveillance of hemodialysis grafts: insights from two case reports.

It is widely recommended that all hemodialysis grafts undergo blood flow (Qa) surveillance, and that stenosis be corrected when accompanied by a low Qa or decrease in Qa (deltaQa). This recommendation has, however, become increasingly controversial. Studies have shown that although there is an association between Qa and thrombosis, the accuracy of Qa in predicting thrombosis within individual patients is poor. We describe two cases that demonstrate common causes of poor predictive accuracy. These cases also show that application of Qa surveillance algorithms is often complex and ambiguous. Most studies reporting that surveillance with intervention reduces thrombosis or prolongs graft life have used historical or sequential control groups, or have been retrospective. Accurate assessment of the benefit of graft surveillance must await studies that are fully prospective and randomized with concurrent control groups. Until such studies have demonstrated sufficient benefit, we do not recommend periodic Qa surveillance with intervention of all hemodialysis grafts.

Association between blood pressure, ultrafiltration, and hemodialysis graft thrombosis: a multivariable logistic regression analysis.

Although a low blood flow (Q(a)) is the most important cause of graft thrombosis, several studies have shown that Q(a) measurements do not accurately predict thrombosis. This suggests that additional variables may influence thrombosis. Identification of such variables may be essential to designing surveillance protocols that accurately predict thrombosis. In this nested case-control study, we prospectively followed 105 patients for up to 2.5 years in order to test the association of a number of variables with thrombosis. These included Q(a) (monthly by ultrasound dilution), percentage stenosis (quarterly by duplex ultrasound), mean arterial pressure (MAP), percentage ultrafiltration (%UF) during dialysis (%UF = 100[liters]/[kilogram of weight]), and other variables that defined patient and graft characteristics. Patients were divided into patent (n = 53) and thrombosed groups (n = 52), and MAP and %UF from seven consecutive dialysis sessions were analyzed. In the thrombosed group, the last session was the final session before thrombosis. A multivariable logistic regression model showed that Q(a), MAP (the predialysis average of seven sessions), and %UF (from the last session) were independently associated with thrombosis, whereas all other variables were not. The model yielded the following odds ratios for thrombosis: for a single Q(a) value (reduction of 1,000 mL/min), 12.0 (P < 0.01); for %UF (increase of 4%), 5.3 (P < 0.01); for MAP (reduction of 30 mm Hg), 4.1 (P = 0.02); and for percentage decrease in Q(a) (> or =20% versus <20%), 2.4 (P = 0.12). We conclude that in addition to Q(a), both %UF at the last session before thrombosis and average predialysis MAP from seven sessions are independently associated with thrombosis. These results help explain why Q(a) alone does not accurately predict thrombosis. A prospective study is needed to determine whether %UF at each session and a moving average MAP from seven sessions improve the prediction of thrombosis. However, it should be recognized that a large %UF is a preterminal event that likely provides too short a warning for intervention before thrombosis.