Does stenting prolong the patency of arteriovenous grafts after thrombectomy and angioplasty?
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Biomedical subjects
Publications and source records attributed to Gerald A Beathard.
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BACKGROUND: The purpose of this report was to analyze the results obtained from a group of interventional nephrologists working in multiple centers performing basic procedures that are used routinely in the management of vascular access problems, with an effort toward establishing standards for evaluating success, complication rates, and acceptable times for procedure duration and fluoroscopy. METHODS: Data on six basic procedures were analyzed-angioplasty of arteriovenous fistulas (AVF-PTA), angioplasty of synthetic grafts (graft-PTA), thrombectomy of arteriovenous fistulas (AVF declot), thrombectomy of synthetic grafts (graft declot), placement of tunneled dialysis catheters (TDC placement), and tunneled dialysis catheter exchange (TDC exchange). These data were examined both as a group and by individual physician operator. RESULTS. A total of 14,067 cases were performed under the six categories of procedure that were the subject of this report; 13,503 cases (96.18%) were successful. The overall complication rate for the combined group of procedures was 3.54%, with 3.26% falling within the minor category and 0.28% within the major. The number of cases performed in each individual category with success rates for each were as follows: TDC placement-1765 cases, 98.24% successful; TDC exchange-2262 cases, 98.36% successful, AVF-PTA-1561 cases, 96.58% successful; graft-PTA-3560 cases, 98.06% successful; AVF declot-228 cases, 78.10% successful; graft declot-4671 cases, 93.08% successful. CONCLUSION: This study demonstrates that appropriately trained interventional nephrologists can perform these basic procedures in both a safe and effective manner.
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BACKGROUND: Fistula failure has been classified as early and late. Early failure refers to those cases in which the arteriovenous (AV) fistula never develops to the point that it can be used or fails within the first 3 months of usage. It has been common practice to abandon these early failures; however, aggressive evaluation and treatment of early fistula failures has been shown to result in the salvage of a large percentage. The two most common causes of the failure seen at this time are juxta-anastomotic stenosis (JAS) and the presence of accessory veins. Both of these can be easily diagnosed by physical examination. This study reports the results of early fistula failure managed aggressively in an attempt at salvage. METHODS: These studies were conducted in six freestanding outpatient interventional facilities in different regions of the United States. Interventional nephrologists are employed at all of these facilities except one that is operated by an interventional radiologist. Each patient was first evaluated angiographically to identify the anatomy of their AV fistula and detect abnormalities that might be present. Stenotic lesions were then treated with angioplasty and accessory veins thought to be significant were obliterated. All patients were then followed to determine if the fistula was usable for dialysis. RESULTS: One hundred patients were identified that met the definition of early failure. Venous stenosis was present in 78% of these cases. In 43% of the cases, the lesion was in the JAS location. In 15%, this was the only lesion present. In 24%, it was associated with an accessory vein, in 6% with a proximal stenosis, and in 4% with both. A proximal stenosis lesion was present in the fistula in 36%. In 6%, it was associated with an accessory vein, in 6% with a JAS, and in 4% with both. The definition of arterial anastomosis stenosis was met in 38% of the cases. This was always in association with JAS. In four cases, a stenotic lesion was present in the artery above the anastomosis. An accessory vein was present in 46% of the cases. In 12% of the cases, this was the only lesion present. In 24% of the cases, this anomaly was associated with JAS, in 6% with proximal stenosis, and in 4% with both. Angioplasty was performed to treat venous stenosis in 72% of the cases with a 98% success rate. Angioplasty of the arterial anastomosis was performed in 38 cases with a 100% success rate. Accessory vein obliteration was performed in 46% of the patients with a 100% success rate. The overall complication rate in this series was 4%, of these 3% were minor and 1% were major. It was possible to initiate dialysis using the fistula in 92% of the cases. Actuarial life-table analysis showed that 84% were functional at 3 months, 72% at 6 months, and 68% at 12 months. CONCLUSION: If correctable pathology is detected in patients with early fistula failure, the incidence of correctable lesions is relatively high and an aggressive therapeutic approach can be expected to have a high yield.
Nephrologists need to deal with the problem of vascular access management in the same manner as the other major problems that affect our dialysis patients. We need to become experts in vascular access and we need to occupy a pivotal position in directing the decisions that are made that affect dialysis patient welfare. An integrated vascular access management strategy is required. Optimally, there should be four components to this strategy - evidence-based policies and procedures, a dedicated vascular access facility, committed vascular access surgeons and the availability of committed vascular access interventionalists. In many respects this is the approach that offers the best in quality of patient care and is also the most economic to deliver.
The technique of percutaneous transluminal angioplasty (PTA) has become routinely used in the management of hemodialysis access dysfunction. It is used for the management of problems that affect both AVF and grafts. In the case of fistulae, it is used for treatment of early failure caused by juxta-anastomotic stenosis and late failure related to venous stenosis. In the case of AVGs, it is used primarily for the management of venous stenosis secondary to neointimal hyperplasia. The technique has been shown to be safe, easily performed, and effective. Details of the procedure, supplies used, complications and their management, and results are reviewed in detail.
Endovascular procedures are becoming the standard of care for the management of hemodialysis (HD) vascular access dysfunction. As with any type of medical procedure, these techniques result in procedure-related complications. The expected frequencies are low. The most frequent procedure-related complication seen in association with angioplasty that dictates the need for intervention is tearing of the vein or vein rupture. The clinical significance of this complication is variable, ranging from none to disaster for the access. The difference lies in the severity of the tear. Management depends on the clinical presentation, ranging from symptomatic measures alone to the need to occlude the graft. Since endovascular thrombectomy is a combined procedure including angioplasty, all of the complications of that procedure can occur with this procedure as well. The major unique procedure-related complication requiring interventional therapy is the occurrence of a symptomatic peripheral artery embolus. This complication can generally be managed successfully by mechanical endovascular means. It is essential that the interventionalist be prepared to manage these complications appropriately when they are encountered.
This study reports a prospective observational study in which an infection prophylaxis protocol based on the National Kidney Foundation's Kidney Disease Outcomes and Quality Initiative (NKF-K/DOQI) guideline 15 describing guidelines for the care of the tunneled dialysis catheter at the time of catheter hook-up for dialysis was used. Catheter-related bacteremia (CRB) incidence data were collected for a 24-month study period and compared to retrospectively collected control data for the immediately preceding 9 months in the same patient population under the same conditions except for the prophylaxis protocol. The incidence of CRB fell from an average level of 6.97 per 1,000 catheter-days during the control period to an average of 1.68 during the study period. This change was statistically significant. Although the lowered incidence required 6 months to reach its maximum, the decreased infection rate was sustained. The average incidence during the last 18 months of the study period was 1.28 per 1,000 catheter-days. Staff compliance with the protocol did require repetitive education and assessment.
One hundred consecutive patients with upper extremity prosthetic grafts referred for either an angioplasty or treatment of a thrombosed graft were included in the study. After the patient's treatment was concluded, the angiographic images that had been created during the case were evaluated to determine if an upper arm vein was evident that would be suitable for the construction of an arteriovenous fistula (AVF). Criteria used to determine suitability included vein size measured at the level of the elbow, feeding artery size at the level of the elbow, absence of stenosis within the vein, and continuity with downstream unobstructed veins. Thirty-eight percent of patients had an upper arm graft and 62% had a lower arm graft. Since it was not possible to adequately evaluate patients with an upper arm graft, these patients were not included in any further evaluations. A total of 46 patients (74%) with a forearm loop graft had one or both of the upper arm veins that appeared to be optimum for the creation of an AVF. If the percentage of graft patients with venous anatomy conducive to the creation of a fistula revealed in this study is representative, then the percentage of fistulas in use could be very quickly increased to more than 50% by simply seizing the opportunity. This effort directed toward prevalent patients could yield results much more rapidly than limiting one's focus to incident patients.
Treatment of early fistula failure can present a challenge as it relates to the evaluation and treatments required for successful management. It can also present a challenge related to accurate and correct coding of the procedures performed. A clinical case is presented in order to discuss the coding of a case with early fistula failure. The procedure is analyzed in detail in order to determine the appropriate codes to apply to the case. The coding is done in accordance with the principles adopted by the American Society of Diagnostic and Interventional Nephrology (ASDIN).
Traditionally hemodialysis vascular access-related procedures have been almost exclusively performed by surgeons and interventional radiologists. In recent years, nephrologists have taken the initiative of performing these procedures themselves. 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. This approach has minimized delays, decreased hospitalizations, and decreased the use of temporary catheters, thereby improving medical care, decreasing costs, and increasing patient convenience. Vascular access-related procedures commonly performed by nephrologists include percutaneous balloon angioplasty, thrombectomy, and tunneled hemodialysis catheter-related procedures. In addition, using vein obliteration and percutaneous balloon angioplasty techniques, nephrologists have recently documented successful salvage of arteriovenous fistulas that had failed to mature, whereas traditionally these fistulas have frequently been abandoned. 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 the safety and success of interventional nephrology. This review focuses on hemodialysis access-related procedures performed by nephrologists and calls for a proactive approach in optimizing this aspect of patient care.
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Evaluation of a newly created fistula 4-6 weeks after surgery should be considered mandatory. If the fistula is going to become adequate for dialysis, it will be apparent at this time. This evaluation can be accomplished by physical examination. However, it must be performed by someone who is knowledgeable. Using a systematic approach facilitates the evaluation and ensures that a problem is not overlooked. Once it is determined that the fistula is dysfunctional, the case should be immediately referred for management to an interventionalist who is experienced in dealing with early fistula failure. The majority of these cases can be salvaged.
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The most common contributing cause of thrombosis of an arteriovenous graft (AVG) in the hemodialysis patient is the presence of venous stenosis. In the face of a recovery of renal function either spontaneously or as a result of renal transplantation, an AVG commonly thromboses. In cases in which the AVG was recently placed, it is unlikely to have had a significant anatomic lesion at the time function was lost. Even though the access that has been left untreated has become a "dead" AVG, it offers an opportunity for "resuscitation." Thirteen cases that met the specific criteria of being placed only a short period of time prior to thrombosis (3 weeks to 6 months), thrombosing after a return of renal function and having been left untreated (3 months to 8 years) were attempted over a 12 year period. The technique applied was modified from the one routinely used based on the presumption that very little or no thrombus was present. The effort was met with success in 8 of the 13 patients. After being opened, the AVG appeared to follow the same patency pattern as other AVGs. It appears that attempting restoration of function of an AVG meeting these criteria may be indicated. Limited experience using this approach in AVGs that do not meet these specific criteria has uniformly met with failure.
As with any type of medical procedure, endovascular procedures result in procedure-related complications (PRCs). A PRC system as part of an outcome-based practice monitoring strategy is essential. Such a program should have several features. It should be realistic, it should be standardized, it should have credibility, it must allow for comparisons with other physicians who are performing the same procedure, and it should be easily accomplished. Currently the only system in popular use is the system designed by the Society of Interventional Radiology (SIR). Definitions within this system are excessively broad and somewhat difficult to apply. This leads to inconsistencies. SIR indicates that their system is intended for use in publications of clinical research and may not be appropriate for use in routine clinical practice. There is a need for a system specifically aimed at and designed for day to day use by the practicing interventionalist whose work is not necessarily directed toward publication. We have described a system from the clinical applications viewpoint.