Stent graft infection and protrusion through the skin: clinical considerations and potential medico-legal ramifications.

Stent grafts have been used for a variety of arteriovenous access associated issues. This article presents three cases of stent graft infection and a case of protruded metal piece of the stent graft through the skin. All four required surgical treatment and three cases required a tunneled dialysis catheter to provide long-term dialysis therapy. This report highlights that stent graft problems can occur that may result in loss of the access. Additionally, strut protrusion can pose a medical hazard to those performing preparation and cannulation of the arteriovenous access.

Patency rates for angioplasty in the treatment of pacemaker-induced central venous stenosis in hemodialysis patients: results of a multi-center study.

While hemodialysis access ligation has been used to manage pacemaker (PM) and implantable cardioverter-defibrillator (ICD) lead-induced central venous stenosis (CVS), percutaneous transluminal balloon angioplasty (PTA) has also been employed to manage this complication. The advantages of PTA include minimal invasiveness and preservation of arteriovenous access for hemodialysis therapy. In this multi-center study we report the patency rates for PTA to manage lead-induced CVS. Consecutive PM/ICD chronic hemodialysis patients with an arteriovenous access referred for signs and symptoms of CVS due to lead-induced CVS were included in this analysis. PTA was performed using the standard technique. Technical and clinical success was examined. Technical success was defined as the ability to successfully perform the procedure. Clinical success was defined as the ability to achieve amelioration of the signs and symptoms of CVS. Both primary and secondary patency rates were also analyzed. Twenty-eight consecutive patients underwent PTA procedure. Technical success was 95%. Postprocedure clinical success was achieved in 100% of the cases where the procedure was successful. The primary patency rates were 18% and 9% at 6 and 12 months, respectively. The secondary patency rates were 95%, 86%, and 73% at 6, 12, and 24 months, respectively. On average, 2.1 procedures/year were required to maintain secondary patency. There were no procedure-related complications. This study finds PTA to be a viable option in the management of PM/ICD lead-induced CVS. Additional studies with appropriate design and sample size are required to conclusively establish the role of PTA in the management of this problem.

Arterial steal syndrome: a modest proposal for an old paradigm.

BACKGROUND: Access ligation has been considered to be the treatment for patients presenting with arterial steal syndrome by many nephrologists. We report results of a prospective study using comprehensive arteriography coupled with percutaneous transluminal balloon angioplasty (PTA) or surgical intervention to evaluate and manage steal syndrome. METHODS: Twelve consecutive patients referred for symptoms of steal syndrome were examined. Comprehensive arteriography of the extremity to diagnose arterial stenoses and delineate anatomy was performed by advancing a diagnostic catheter into the subclavian artery. Findings of arteriography and degrees of stenosis before and after PTA also were documented. Resolution of symptoms after PTA and surgical interventions, as well as complications, were recorded. RESULTS: Angiography showed arterial stenotic lesions in 10 of 12 patients (83%). The degree of stenosis was 66% +/- 14% (SD). Eight patients (80%) with stenotic lesions underwent PTA successfully. The degree of stenosis after PTA was 13% +/- 10%. The remaining 2 patients were not considered candidates for PTA and were referred to surgery with arteriography images. One patient underwent ligation and the other patient required an axillary loop fistula using the same outflow vein. The 2 patients without stenoses showed excessive steal through the anastomosis and underwent lengthening procedures by insertion of a vein segment. All 12 patients are symptom free with a mean follow-up of 8.3 +/- 4 months, and 11 of 12 patients (92%) are dialyzing using the same access. There were no procedure-related complications. CONCLUSION: We suggest that complete imaging of the arterial circulation of the extremity be considered in patients presenting with symptoms of steal syndrome to properly assess the arterial anatomy and develop a treatment strategy.

Predictors of alkalosis after liver transplantation.

BACKGROUND: Metabolic alkalosis (MA) is common after orthotopic liver transplantation (OLT). METHODS: The study was conducted to identify factors associated with MA after 285 OLTs. MA, defined as total carbon dioxide content of 30 mEq/L or greater, developed in 115 patients (40%) within the first 3 postoperative days. RESULTS: By univariate analysis, patients with MA had a greater preoperative carbon dioxide content (24.4 +/- 3 versus 22.9 +/- 2.9 mEq/L; P < 0.0001) and hematocrit (35% +/- 5% versus 33% +/- 6%; P < 0.02), but lower creatinine (0.9 +/- 0.5 versus 1.2 +/- 1.2 mg/dL; P < 0.001) and blood urea nitrogen levels (15 +/- 12 versus 19 +/- 17 mg/dL; P < 0.001) compared with controls. Patients with MA were administered more citrate intraoperatively compared with controls (6.2 +/- 5.2 versus 4.5 +/- 3.6 mEq/kg of body weight; P < 0.02). Patients with MA had a lower postoperative potassium level (3.7 +/- 0.4 versus 4 +/- 0.5 mEq/L; P < 0.0001) and cumulative fluid balance (-0.66 +/- 1.87 versus +0.003 +/- 3.9 L; P < 0.007) compared with controls. By multivariate analysis, preoperative carbon dioxide content (odds ratio, 1.19; 95% confidence interval [CI], 1.08 to 1.31 per mEq/L), creatinine level (odds ratio, 0.61; 95% CI, 0.39 to 0.96 per mg/dL), intraoperative administered citrate (odds ratio, 3.35; 95% CI, 1.71 to 6.53 per 10 mEq/kg body weight), and postoperative potassium level (odds ratio, 0.32; 95% CI, 0.18 to 0.57 per mEq/L) were independently associated with MA. MA was not associated with increased hospital mortality (7.8% versus 8.2%, MA versus controls). However, patients with MA spent more time on mechanical ventilation than controls (5 +/- 0.8 versus 3 +/- 0.6 days; P < or = 0.03). CONCLUSION: Preoperative total carbon dioxide content, renal function, intraoperative administered citrate, and postoperative potassium level are independently associated with MA after primary OLT.

Peritoneoscopic placement of peritoneal dialysis catheter and bowel perforation: experience of an interventional nephrology program.

BACKGROUND: Bowel perforation is an uncommon but serious complication of peritoneoscopic peritoneal dialysis (PD) catheter insertion. The approach to diagnosis of bowel perforation utilizing this technique has not been previously published. The authors report their experience with the diagnosis and management of bowel perforation in the context of peritoneoscopic placement of PD catheters. METHODS: The authors retrospectively reviewed the records of 750 PD catheters inserted over a 12-year period (January 1991 to May 2003) utilizing peritoneoscopic technique. RESULTS: Six (0.8%) patients experienced bowel perforation during the procedure. The diagnosis was made immediately during the procedure in 5 (83%) of the 6 patients. Of these 5, peritoneoscopy confirmed intrabowel position of the cannula by visualizing bowel mucosa (n = 3) and hard stool (n = 1). The fifth patient showed extrusion of fecal matter upon trocar withdrawal before peritoneoscopy. All 5 had emanation of foul-smelling gas through the cannula. Bowel rest and broad-spectrum intravenous antibiotics were initiated. Of the 5, 1 required surgery, whereas the others were discharged home after 3 days. The sixth patient had fever, severe peritoneal irritation, and polymicrobial peritonitis the morning after the procedure. In this patient, no evidence of bowel injury was noted during the procedure except for brief emanation of foul-smelling gas. He required surgical intervention. CONCLUSION: Bowel perforation can be diagnosed immediately in most patients undergoing peritoneoscopic PD catheter insertion. A majority of these patients can be treated medically. The surgical team should be consulted if the patient shows clinical deterioration or has signs of peritoneal irritation.

Nephrology nurses in a new role: diagnostic and interventional nephrology.

Diagnostic and interventional nephrology is a growing subspecialty of nephrology. Increasingly, procedural care of nephrology patients is being managed by nephrologists trained in this area. As a result, new opportunities have been created for nephrology nurses as they assist these interventionists in the administration of care in diagnostic and interventional nephrology. This article describes the components of a diagnostic and interventional nephrology program, the initiation of such a program at a university center, and the role of nephrology nursing personnel in this rapidly developing area.

Salvage of problematic peritoneal dialysis catheters.

Peritoneal dialysis (PD) is a markedly underutilized modality for permanent renal replacement therapy in the United States owing to a low rate of patient referral and high rate of patient dropout or transfer to hemodialysis. One cause for patient loss from PD is problematic PD catheters that often are removed rather than being subjected to simple surgical salvage procedures. We report three patients with problematic catheters and our approach to their management. The first patient developed erosion of the skin overlying the portion of the catheter between the deep and superficial cuffs after 6 months of PD. The second patient developed extrusion of the superficial cuff after 4 years of PD. The third patient demonstrated a localized abscess at the incision site for catheter insertion after 3 years of PD. Other than a mild superficial exit site infection and localized abscess in the second and third patient, respectively, there were no associated infections of the catheter tunnel and cuff or of the peritoneal cavity as determined by either clinical examination, ultrasound evidence of fluid collection, or cultures and white blood cell counts. All three cases were managed successfully by interventional nephrology on an outpatient basis and under local anesthesia without either catheter removal or placement of a new PD catheter. It was possible to continue uninterrupted PD in the first and third patients, while the second patient had temporary hemodialysis to allow for complete healing of the surgical wound. We conclude that in selected cases simple interventions can salvage problematic PD catheters and maintain patients on PD.

Utility of static pressure ratio recording during angioplasty of arteriovenous graft stenosis.

Intra-access static pressure ratio (SPR) (intra-access pressure/mean arterial pressure) can be measured during angioplasty (PTA) to assess the functional importance of an arteriovenous graft (AVG) stenosis. We used SPR in 70 patients with AVGs who underwent 98 angioplasty procedures. SPR was measured during angioplasty by placing a catheter tip at mid-access. Inflow stenosis (IF) = stenosis proximal to the tip of the catheter. Outflow stenosis (OF) = stenosis distal to the tip of the catheter up to the superior vena cava-atrial junction. Post PTA, access flow (Qa) was assessed within 2 weeks. Complete data sets for both SPR and Qa were available in 83 procedures. Using a normal SPR ratio of 0.3-0.4 at mid-graft, three patterns of SPR were noted. In 63 of 83 (76%) cases SPR was elevated prior to PTA (0.71 +/- 0.13 SD). PTA reduced SPR toward normal range (0.44 +/- 0.12) in 53 cases (84%). In the remaining 10 (16%), SPR decreased to a low value (0.22 +/- 0.03) and normalized (0.40 +/- .0.11) only after PTA of a coexisting inflow stenosis. In 12 of 83 (14%) procedures, the initial SPR was low (0.18 +/- 0.04) and increased toward normal (0.3 +/- 0.08) following IF stenosis PTA in seven (58%) cases. For the remaining five (42%) cases SPR increased to a high value (0.70 +/- 0.21) and decreased toward normal range (0.33 +/- 0.07) only after OF stenosis angioplasty. In 8 of 83 (10%) procedures, initial SPR was normal (0.33 +/- 0.02). Angiography revealed coexisting IF and OF stenoses. SPR remained within the normal range after PTA of these lesions (0.33 +/- 0.02). Qa increased significantly in 74 of 83 (89%) procedures (before = 572 +/- 201, after = 1109 +/- 368 ml/min; p < 0.001). SPR measurements can assist in hemodynamic assessment of an AVG during angioplasty procedure.

Inflow stenosis in arteriovenous fistulas and grafts: a multicenter, prospective study.

BACKGROUND: Traditionally, arteriovenous hemodialysis access inflow stenosis has been reported to occur infrequently (0% to 4%). In contrast, recent reports have suggested a significantly higher incidence (14% to 42%). Interpretation of these studies has been complicated by the presence of one or more confounding factors such as retrospective study design, small sample size, arteriovenous fistulas grouped with grafts to determine the incidence of inflow stenosis, inclusion of fistulas that had failed primarily, failure to provide adequate definition of inflow stenosis, and the technique of retrograde angiography. This is a report of a prospective, multicenter study to examine the incidence of inflow stenosis separately in arteriovenous fistulas and grafts. METHODS: Patients were referred to interventional nephrology either for percutaneous balloon angioplasty or thrombectomy procedures. Angiography to evaluate access inflow (arterial anastomosis and adjacent vascular structures) was performed in all cases. This was accomplished by retrograde angiography using either manual occlusion of the venous side and/or advancing a diagnostic catheter across the arterial anastomosis. Multiple images using digital subtraction angiography were recorded in multiple planes. An inflow stenosis was defined as stenosis within the arterial system, artery-graft anastomosis (graft cases), artery-vein anastomosis (fistula cases) and juxta-anastomotic region (the first 2 cm downstream from the arterial anastomosis). Vascular stenosis was defined as >/=50% reduction in luminal diameter judged by comparison with either the adjacent vessel or graft. A standardized definition for anastomotic stenosis was applied. RESULTS: Two hundred and twenty three consecutive procedures (grafts, 122; fistulas, 101) were performed in 158 patients. Inflow stenosis occurred in 36/122 (29%) in graft cases. All had a coexisting stenosis on the venous side. In fistula cases, 41/101 (40%) had inflow stenosis. Of these, 22 (54%) had a coexisting lesion on the venous side. Overall, inflow stenosis occurred in 77/223 procedures (35%). CONCLUSION: This prospective, multicenter study demonstrates that access inflow stenosis occurs in one third of the cases referred to interventional facilities with clinical evidence of venous stenosis or thrombosis. This is much higher than has been traditionally reported.

Peritoneal dialysis underutilization: the impact of an interventional nephrology peritoneal dialysis access program.

Peritoneal dialysis (PD) is an underutilized form of renal replacement therapy. Recent data have emphasized that only 12% of end-stage renal disease (ESRD) patients are initiated on this form of therapy in the United States. Patients requiring PD have most often been referred to general surgeons for catheter placement. This has incurred additional delays in starting treatment and loss of decision-making control by the referring nephrologist. To address this issue, we developed and incorporated our own PD access placement program into the preexisting chronic kidney disease (CKD) education program. To date, 46 patients have undergone 71 procedures. These included 51 (72%) PD catheter insertions, 14 (20%) removals, and 6 (8%) repositioning procedures for poor drainage. PD catheter insertion was performed peritoneoscopically under local anesthesia and a Fogarty catheter was used to reposition a migrated catheter. All of the procedures were performed by nephrologists in a dedicated interventional nephrology (IN) laboratory. All six repositioning procedures failed to restore optimal drainage. Five of these patients had the catheter removed and a new catheter placed during the same procedure. Of these five patients, one had recurrence of poor drainage and opted for hemodialysis (HD). The sixth patient declined reinsertion and chose HD. Of the remaining seven removal procedures, three were due to fungal peritonitis, one due to bowel perforation, one due to severe depression, one due to transplant, and one catheter was removed at the request of the primary physician in a terminally ill patient. Eight of the 51 catheter insertions were during the initial admission of a catastrophic dialysis start. Two of these patients started acute PD and avoided catheter placement for HD. Thirty-seven of 46 patients have a functional PD catheter with a follow-up of 8.6 +/- 0.8 (mean +/- SE) months. During an 18-month period our PD population has increased from 43 to 80 patients. We conclude that a dedicated PD access placement program coupled with a CKD education program can have a dramatic impact on patient choice and PD growth.

Modification of the peritoneoscopic technique of peritoneal dialysis catheter insertion: experience of an interventional nephrology program.

Bowel perforation is a well-recognized complication of peritoneal dialysis catheter insertion and is associated with increased morbidity and cost of medical care. In this article we describe our 2-year experience (August 2001-October 2003) with a modified peritoneoscopic technique of peritoneal dialysis catheter insertion to minimize the incidence of bowel perforation. Seventy patients underwent 82 consecutive peritoneal dialysis catheter insertions using the innovative technique. The modified technique is very similar to the traditional peritoneoscopic procedure except for the following differences. To gain access to the peritoneal cavity, a Veress insufflation needle (Ethicon Endo-Surgery Inc., Cincinnati, OH) is utilized instead of the trocar. In contrast to the sharp tip of the trocar, the Veress needle has a blunt, self-retracting end. In addition, the Veress needle is only 14 gauge as opposed to the 2.2 mm diameter of the trocar. Upon introduction of the Veress needle into the abdominal cavity, two "pops" are discerned similar to the trocar. After introduction, 400-500 cc of air are infused and the needle is removed. The infusion of air creates a space between the peritoneal surface of the anterior abdominal wall and the bowel loops. At this point, the cannula with trocar is inserted into the space created. The rest of the steps of the procedure are the same as the traditional peritoneoscopic technique. Utilizing the innovative technique, all 82 catheter insertions were performed successfully without a single bowel perforation. No other complications except for catheter migration (n = 2) were noted. The extra cost of the needle (35 USD) should be viewed in the context of the costs associated with management of a bowel perforation. Large-scale studies are needed to confirm the superiority of this innovative technique over the traditional peritoneoscopic insertion found in our case series. In the interim, however, the increased morbidity and cost associated with bowel perforation calls for logical measures to be taken to avoid this dreaded complication.