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Arif Asif

Publications and source records attributed to Arif Asif.

At least 19 recordsLinked to original sources
PubMed2006

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.

Adult↗
PubMed2006

Strategies to minimize tunneled hemodialysis catheter use.

While the use of arteriovenous grafts has recently declined, there has been an astronomical increase in hemodialysis patients dialyzing with tunneled dialysis catheters (TDCs). Recent data have indicated that over 70% of the patients with end-stage renal disease initiate dialysis with a catheter. Additionally, up to 27% of the end-stage renal disease patients in the US are using TDCs as their permanent access, with placement rates having doubled since 1996. Although most modern catheters claim to provide adequate blood flow for dialysis, they are associated with the highest incidence of complications, morbidity and mortality when compared with other types of vascular access. It is for these reasons that the National Kidney Foundation Dialysis Outcomes Quality Initiative guideline 30 as well as the Fistula First Change Concept 7 emphasize limiting the use of catheters and fostering the creation of arteriovenous fistulae. Early referral has clearly been shown to minimize the use of TDCs and maximize fistulae. This report focuses on the role of additional measures that minimize TDC use, such as dialysis modality presentation and peritoneal dialysis, vascular access education, preoperative vascular mapping and salvage of early failure and thrombosed fistulae.

Catheters, Indwelling↗
PubMed2005

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.

Adult↗
PubMed2005

Conversion of tunneled hemodialysis catheter-consigned patients to arteriovenous fistula.

OBJECTIVE: Despite their high incidence of complications, costs, morbidity, and mortality, nearly 27% of the chronic hemodialysis (HD) patients are receiving treatment via a tunneled hemodialysis catheter (TDC). METHODS: In this prospective analysis, an interventional nephrology team employed an organized program consisting of vascular access (VA) education and vascular mapping (VM) to TDC-consigned patients. A full range of surgical approaches for arteriovenous fistula (AVF) creation, including vein transpositions, was exercised. Physical examination was performed every 1 to 2 weeks after surgery to assess the development of the AVF. Fistulas that failed to develop adequately to support HD (early failure) underwent salvage [percutaneous transluminal angioplasty (PTA), accessory vein obliteration (AVL)] procedures. RESULTS: One hundred twenty-one TDC-consigned patients received VA education. Eighty-six (71%) agreed to undergo VM. Two groups were identified. Group I (N= 66; using TDC for 7.2 +/- 1.8 SD months) had never had an arteriovenous access; group II (N= 20; using TDC for 12.3 +/- 4.0 months) had a history of one or more previously failed arteriovenous accesses. Upon VM, 64/66 (97%) in group I and 18/20 (90%) in group II were found to have adequate veins for AVF creation. Seven patients (11%) in group I and 3 (17%) in group II refused surgery. In group I, 57 (89%) received an arteriovenous access (radiocephalic AVF = 15, brachiocephalic AVF = 35, transposed brachiobasilic AVF = 3, brachiobasilic AVG = 4). In group II, 15 (83%) received a transposed AVF (radiobasilic = 2, brachiobasilic = 13). Sixteen fistulas (30%) in group I and 8 (53%) in group II had early failure. All except for one fistula in each group were salvaged using PTA and/or AVL. All 70 accesses (AVF = 66, AVG = 4) remain functional, with a mean follow-up of 8.5 +/- 3.6 months. CONCLUSION: These results demonstrate that an organized approach based upon a comprehensive program utilizing VA counseling, VM, application of full range of surgical techniques, and salvage procedures can be very successful in providing optimum vascular access to the catheter-dependent patient.

Adult↗
PubMed2005

Vascular access education, planning and percutaneous interventions by nephrologists.

To optimize vascular access care of patients with end stage renal disease, nephrologists themselves are taking a keen interest in the management of vascular access-related issues. Because of their unique clinical perspective on dialysis access and better understanding of the intricacies of renal replacement therapy, nephrologists are ideally suited for this activity. Two areas are the main focus of attention by these specialists: vascular access education and access-related percutaneous interventions. Vascular access-related procedures commonly performed by nephrologists include percutaneous balloon angioplasty for vascular access stenosis, thrombectomy procedure for a thrombosed arteriovenous access, tunneled hemodialysis catheter-related procedures and vascular mapping to determine the patient's optimal vascular access. While 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 emphasized that a nephrologist can be successfully trained to become a competent interventionalist. In addition to documenting excellent outcome data, multiple reports have demonstrated safety and success when these procedures are performed by nephrologists. This chapter focuses on vascular access education and hemodialysis access-related procedures performed by nephrologist and calls for a proactive approach in optimizing this aspect of patients care.

Angioplasty, Balloon↗
PubMed2004

Prevention of radiocontrast-induced nephropathy.

Radiocontrast administration is a common cause of hospital-acquired acute renal failure. It is associated with significant in-hospital and long-term morbidity and mortality and increases the costs of medical care by at least extending the hospital stay. Although individuals with normal renal function generally are not considered to be at particular risk, patients with preexisting renal failure are much more likely to experience this complication after radiocontrast agent administration. Typically, serum creatinine levels begin to increase at 48 to 72 hours, peak at 3 to 5 days, and return to baseline within another 3 to 5 days. A variety of therapeutic interventions, including saline hydration, diuretics, mannitol, calcium channel antagonists, theophylline, endothelin receptor antagonists, and dopamine, have been used in an attempt to prevent radiocontrast-induced nephropathy. Of these, saline hydration is the sole efficacious therapy to protect against radiocontrast-induced nephropathy. Recent advances have examined the impact of fenoldopam (dopamine-1 [DA-1] receptor; DA-1 agonist), the antioxidant N-acetylcysteine, iso-osmolar contrast agents, hemodialysis, and hemofiltration in ameliorating radiocontrast-induced nephropathy. This review focuses on current interventions to ameliorate radiocontrast-induced acute renal failure and provides an analysis of some of the recent studies conducted to halt radiocontrast-induced nephropathy.

Acetylcysteine↗
PubMed2004

Dopamine-1 receptor agonist: renal effects and its potential role in the management of radiocontrast-induced nephropathy.

Radiocontrast-induced nephropathy remains the third leading cause of hospital-acquired acute renal failure. Once established, this syndrome is associated with increased morbidity and mortality as well as increased health care costs. Recently, studies have been initiated to evaluate the potential of a selective dopamine-1 receptor agonist (fenoldopam) in ameliorating radiocontrast-induced renal failure. Selective dopamine-1 receptor agonists exhibit many desirable renal effects that support their use for the prophylaxis of radiocontrast-induced nephropathy, including decreases in renal vascular resistance and increases in renal blood flow, glomerular filtration, and sodium and water excretion. Several reports have documented a beneficial effect of fenoldopam administration in attenuating radiocontrast-induced nephropathy. In contrast, a recent multicenter, randomized study did not demonstrate a renoprotective effect of fenoldopam against radiocontrast-induced nephropathy. The presence of multiple confounders, however, precludes a definitive conclusion regarding the ability of fenoldopam to protect against radiocontrast-induced nephropathy. Additional studies are needed to properly evaluate the role of fenoldopam in radiocontrast-induced nephropathy prophylaxis.

Acute Kidney Injury↗
PubMed2003

Developing a comprehensive diagnostic and interventional nephrology program at an academic center.

Procedure-related delays in the treatment of patients with renal disease can be minimized and nephrology care can be delivered more efficiently by a nephrologist trained in nephrology-related procedures. Referrals to a radiologist for renal ultrasound and biopsy, to a surgeon for dialysis access placement, and to an interventional radiologist for dialysis catheter placement and vascular access procedures are time consuming and inconvenient to patients with renal disease. Moreover, such an approach may result in delays in the availability of critical diagnostic information and a break in the continuity of care. In an effort to optimize the care of nephrology patients, we developed a diagnostic and interventional nephrology (DIN) program that effectively deals with nephrology-related procedures in a timely manner. At present, some of the commonly performed nephrology-related procedures at our center include diagnostic ultrasonography, ultrasound-guided renal biopsy, peritoneal dialysis access procedures, permanent tunneled hemodialysis catheter placement, and endovascular procedures for arteriovenous dialysis access dysfunction. To date, we have performed 893 procedures during a period of 2 years. This article describes our approach and the tools required to develop a DIN program at an academic medical center.

Academic Medical Centers↗
PubMed2003

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.

Abdomen, Acute↗
PubMed2003

Short-term, high-dose pamidronate-induced acute tubular necrosis: the postulated mechanisms of bisphosphonate nephrotoxicity.

A 76-year-old man had biopsy-proven acute tubular necrosis (ATN) after intravenous administration of 3 doses of 60 mg of pamidronate (Aredia) over a 2-week period. Pamidronate was given to treat hypercalcemia of unknown etiology. Other potential causes of acute renal failure were excluded with appropriate investigations. The patient's preexisting renal impairment in the context of high-doses of pamidronate might have been a potentiating factor for nephrotoxicity. The ATN encountered in this patient resolved; however, short-term hemodialysis was needed. To the best of our knowledge, this is the first reported case of short-term, high-dose pamidronate-induced ATN in the absence of concomitant nephrotoxins. Although necrotic and apoptotic cell death after bisphosphonate administration has been seen in a variety of cells, the exact mechanism of nephrotoxicity is unknown. This report presents a case of pamidronate-induced ATN and discusses the potential mechanisms of bisphosphonate-induced nephrotoxicity.

Aged↗
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

Diagnostic and interventional nephrology.

The fragmented care of nephrology patients that results from referral to a radiologist for renal ultrasound (US) and biopsy, a surgeon for dialysis access placement, and an interventional radiologist for dialysis catheter placement and vascular access procedures often leads to delays in the treatment of these patients. Many specialists perform and interpret sonograms particular to their specialty rather than relying on technicians for performance and radiologists for interpretation, and nephrologists recently have begun to embrace this technology as an aid in the diagnosis and treatment of their patients. By combining an understanding of the pathophysiology of renal disease with the ability to perform clinical correlation and apply the laboratory data, the nephrologist is ideally suited to perform and interpret renal US and US guidance for percutaneous renal biopsies. Additionally, patients requiring peritoneal dialysis (PD) access have traditionally been referred to a general surgeon for catheter placement, which incurs additional delay in therapy and loss of decision-making control by the referring nephrologist. Recent data has emphasized that the peritoneal dialysis access procedure can be performed safely and effectively by a nephrologist trained in PD access procedures. Nephrologists also successfully perform tunneled hemodialysis catheter placement and vascular access procedures on an outpatient basis. The medical needs of patients with renal disease can be safely and efficiently delivered by a nephrologist trained in interventional nephrology (IN). This growing area of expertise will minimize delays, reduce cost, and allow physicians with training in the management of end-stage renal disease (ESRD) patients to be involved in the procedural aspects of their patients' care. An aggressive approach to the development of IN training programs at academic centers is warranted.

Adult↗
PubMedDate not supplied

Radiocontrast-induced nephropathy.

Radiocontrast administration remains the third leading cause of hospital-acquired acute renal failure. Clinically, radiocontrast-induced nephropathy (RIN) is defined as a sudden decline in renal function after radiocontrast administration. Typically, the serum creatinine level begins to increase at 24 to 72 hours after the administration of contrast, peaks at 3 to 5 days, and requires another 3 to 5 days to return to baseline. RIN increases the incidence of life-threatening complications such as sepsis, bleeding, and respiratory failure and increases the cost of medical care by extending the hospital stay. The increased mortality associated with acute renal failure encountered in this scenario calls for a heightened awareness of the diagnosis and prevention of RIN. Whereas individuals with healthy renal function are not generally considered to be at particular risk for RIN, patients with preexisting renal insufficiency and diabetes mellitus are much more likely to experience acute renal failure after contrast administration. In the past, a variety of therapeutic interventions have been used to prevent or attenuate RIN, including saline hydration, diuretics, mannitol, calcium channel antagonists, theophylline, endothelin receptor antagonists, hemodialysis, and dopamine. More recently, studies demonstrate a positive impact of fenoldopam (dopamine-1 receptor, dopamine-1 agonist) and the antioxidant N-acetylcysteine in ameliorating RIN. This article discusses the pathophysiology, risk factors, and prevention of RIN.

Acute Kidney Injury↗
PubMedDate not supplied

Current trials of interventions to prevent radiocontrast-induced nephropathy.

Radiocontrast administration is a common cause of hospital-acquired acute renal failure. It is associated with significant in-hospital and long-term morbidity and mortality and increases the costs of medical care by at least extending the hospital stay. A variety of therapeutic interventions, including saline hydration, diuretics, mannitol, calcium channel antagonists, theophylline, endothelin receptor antagonists, and dopamine, have been employed to prevent radiocontrast-induced acute renal failure. Recent advances have examined the impact of fenoldopam (dopamine-1 receptor agonist), N-acetylcysteine (antioxidant), iso-osmolar contrast agents, hemodialysis, and hemofiltration on ameliorating radiocontrast-induced acute renal failure. Although hydration with half-normal saline had remained the gold standard for the prevention of radiocontrast-induced nephropathy, recent data have revealed the superiority of hydration with normal saline over half-normal saline. This review focuses on the most recent studies of interventions to ameliorate radiocontrast-induced acute renal failure and provides a critical analysis of some of the recent studies conducted to prevent radiocontrast-induced nephropathy.

Acetylcysteine↗
PubMedDate not supplied

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.

Adult↗