Shahriar Moossavi

Re-evaluating the Fistula First Initiative in Octogenarians on Hemodialysis.

BACKGROUND AND OBJECTIVES Octogenarians frequently require maintenance hemodialysis (HD) for treatment of stage renal disease ESRD. Although the Fistula First Initiative recommends creating an arteriovenous fistula as the preferred dialysis access method, vascular access selection should be based on life expectancy and functional status at treatment initiation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This is a retrospective analysis of 4-year outpatient data (January 1, 2004 through December 31, 2007) of incident octogenarian dialysis population in an academic institution. Thirty-nine of 268 patients were octogenarians with a mean (± SD) age of 83.4 ± 3.4 years, and 25 were men. Kaplan-Meier survival and Fishers post hoc statistical analyses were performed. RESULTS Thirty-seven octogenarian patients selected HD and two selected peritoneal dialysis. Among the 37 HD patients, 29 initiated dialysis with a tunneled cuffed catheter, 6 with an arteriovenous fistula, and 2 with an arteriovenous graft. Three patients regained renal function after an average 112 days and one was lost to follow-up. Of the 33 remaining on HD, 8 required nursing home admission and 25 were discharged home after initiating HD. Among these 33, 19 died and 14 remained on HD at the end of study period. Days on dialysis (mean ± SEM) before death in those discharged to a nursing facility versus home were 52.6 ± 14.7 versus 386.1 ± 90.7 (P < 0.05), respectively. CONCLUSIONS Vascular access planning should include assessment of functional status and life expectancy in octogenarian HD patients.

Race-Specific Relationships Between Coronary and Carotid Artery Calcification and Carotid Intimal Medial Thickness

Background and Purpose— Calcified arterial plaque has been proposed as a subclinical marker of atherosclerosis. We compared it to a well-validated surrogate—carotid intimal medial thickness (IMT). Methods— Calcified arterial plaque was measured in 2 vascular beds (coronary and carotid) by computed tomography, and common carotid artery IMT was measured by B-mode ultrasonography, in 438 participants. Results— Calcium was positively associated with IMT (r = 0.36 for coronary and r = 0.45 for carotid, both P < 0.0001). Correlations were attenuated with adjustment for age, sex, and diabetes. Conclusions— Calcified plaque in the coronary and carotid arteries is moderately associated with subclinical atherosclerosis.

Non-surgical salvage of thrombosed arterio-venous fistulae: a case series and review of the literature.

Attempts to salvage thrombosed hemodialysis arterio‐venous fistulae (AVF) using interventional techniques are not universally performed. Patients often require temporary dialysis catheters pending creation of a new vascular access. We determined the long‐term outcome of interventional (non‐surgical) repair of completely thrombosed AVF in 49 consecutive accesses (22 radio‐cephalic, 1 radio‐basilic, 19 brachio‐cephalic, and 7 brachio‐basilic) referred for an intervention within 48 hours of thrombosis. Subjects were 65% male (32), with mean ± SD age 63.7 ± 13.5 years (range 33–91), 51% African‐American (25), 47% Caucasian (23) and 65% had diabetes (32). Overall, 96% (47/49) of thrombosed AVF were salvaged with complications observed in four cases (two extravasations of contrast; two radial artery emboli), with no serious long‐term sequelae. Interventional procedures included 34 venous angioplasties, 11 venous angioplasties with stenting and two combined venous and arterial angioplasties. The primary and secondary patency rates for all salvaged AVF were 50.5 ± 8.7%, 72.5 ± 7.8% at 1 year, and 43.3 ± 10%, 55.4 ± 12.7% at 2 years, respectively. The median estimate to first intervention after the declot procedure was 14.7 months. The median estimate for continued function exceeded 23.1 months. There was no significant statistical difference in the primary (p = 0.73) and secondary patency rates (p = 0.057) for forearm vs. upper arm AVF. We conclude that interventional repairs should routinely be employed to salvage newly thrombosed AVF. The vast majority of these individuals can avoid receiving dialysis catheters or placement of a new dialysis vascular access.

Successful Models of Interventional Nephrology at Academic Medical Centers

The foundation of endovascular procedures by nephrologists was laid in the private practice arena. Because of political issues such as training, credentialing, space and equipment expenses, and co-management concerns surrounding the performance of dialysis-access procedures, the majority of these programs provided care in an outpatient vascular access center. On the basis of the improvement of patient care demonstrated by these centers, several nephrology programs at academic medical centers have also embraced this approach. In addition to providing interventional care on an outpatient basis, academic medical centers have taken a step further to expand collaboration with other specialties with similar expertise (such as with interventional radiologists and cardiologists) to enhance patient care and research. The enthusiastic initiative, cooperative, and mutually collaborative efforts used by academic medical centers have resulted in the successful establishment of interventional nephrology programs. This article describes various models of interventional nephrology programs at academic medical centers across the United States.

Dialysis Vascular Access Management by Interventional Nephrology Programs at University Medical Centers in the United States

The development of interventional nephrology has undoubtedly led to an improvement in patient care at many facilities across the United States. However, these services have traditionally been offered by interventional nephrologists in the private practice arena. While interventional nephrology was born in the private practice setting, several academic medical centers across the United States have now developed interventional nephrology programs. University Medical Centers (UMCs) that offer interventional nephrology face challenges, such as smaller dialysis populations, limited financial resources, and real or perceived political “turf” issues.” Despite these hurdles, several UMCs have successfully established interventional nephrology as an intricate part of a larger nephrology program. This has largely been accomplished by consolidating available resources and collaborating with other specialties irrespective of the size of the dialysis population. The collaboration with other specialties also offers an opportunity to perform advanced procedures, such as application of excimer laser and endovascular ultrasound. As more UMCs establish interventional nephrology programs, opportunities for developing standardized training centers will improve, resulting in better quality and availability of nephrology‐related procedures, and providing an impetus for research activities.

Cannulating the hemodialysis access through a stent graft - is it advisable?

Pseudoaneurysms frequently develop at cannulation sites in arteriovenous grafts. The current treatment options are either open surgical revision or endovascular placement of stents to cover the pseudoaneurysm. The ideal treatment option needs to be individualized based on the clinical assessment and the involved risks with the procedure. The safety of cannulating the dialysis access through a stent graft for hemodialysis has not been conclusively established and needs to be avoided when possible. This case report emphasizes the hazards associated with cannulation of stent grafts, including stent fracture and leakage of blood into the surrounding tissue with recurrence of pseudoaneurysm.

Retrospective analysis of catheter recirculation in prevalent dialysis patients.

Catheter recirculation (CR) occurs when blood returning from the venous limb of the catheter re‐enters the arterial limb of the catheter without passage through the circulation. Adequacy of dialysis is influenced by the degree of access recirculation. In this study we evaluate factors influencing the degree of dialysis central venous catheter (CVC) recirculation in prevalent hemodialysis patients. This is a retrospective study of all patients undergoing hemodialysis via a catheter at the Wake Forest University Outpatient Dialysis Facilities from September 1, 2006 to May 15, 2007. CR was correlated to catheter type, catheter brand, site of placement, catheter length, time on dialysis, time on the current catheter, and was measured via ultrasound dilution technique. A total of 165 catheters were identified. Seventy‐one catheters were in the right internal jugular position, 43 in the left internal jugular position, 13 in the right subclavian, one in the left subclavian, eight in the right femoral, two in the left femoral, and four in the trans‐lumber position. CR was 6.3 ± 7.5% in symmetric tip catheters (n = 14), 6.0 ± 8.3% in split‐tip catheters (n = 102), 8.4 ± 11.7% in step‐tip catheters (n = 10), and 23.0 ± 8.2% in temporary catheters (n = 3), respectively. These results are borderline significant if temporary catheters are included (p = 0.052); however, the overall p‐value is only 0.80 for tunneled dialysis catheters. There was no correlation between CR and time on dialysis (p = 0.66) or time on the current catheter (p = 0.48). The current study suggests that the CVC recirculation is independent of catheter brand, type, time on dialysis, or time on current catheter.

Long‐term outcomes of transposed basilic vein arteriovenous fistulae

The need for reliable, long‐term hemodialysis vascular access remains critical. To determine the long‐term outcomes of transposed basilic vein arteriovenous fistulae (BVT) and their comparability with other vascular accesses, we determined retrospectively the primary and secondary patency rates in 58 BVT and in a total of 58 arteriovenous fistulae (AVF) and arteriovenous grafts (AVG) at a single center. Fifty‐eight BVT were placed in 57 individuals, 69% after prior vascular access failure. Ten BVT failed before initial use and 2 patients expired with functioning accesses before dialysis initiation. In all 58 BVT, 46.8±10.8% functioned at 3 years, with median survival 30.8 months. Limiting analyses to the 46 BVT that were ultimately accessed, 3‐year primary and secondary patency rates were 38.3±7.7% and 56.5±12.6%, respectively. Lower ejection fraction (p=0.054) and greater numbers of prior permanent dialysis catheters (p=0.005) were present in those with failed BVT. Compared with AVF, BVT had similar 3‐year primary and secondary patency rates. The secondary patency rate was significantly better for BVT vs. AVG over the observation period; at 3 years, the rates were 56.5±12.6% vs. 9.1±6.0% (p=0.002), respectively. Basilic vein arteriovenous fistulae are valuable hemodialysis accesses. Although nearly 20% of newly placed BVT will not function before first use, those that are functional have median survivals exceeding 6 years, and 38% will not require intervention within 3 years of initial use.

Broken Clamp on a Cuffed Tunneled Catheter—Are All Catheters Equal?

The use of a cuffed tunneled catheter (CTC) as an initial access in the incident hemodialysis population in the United States remains high. Several different brands of catheters are available for clinical use. Their mechanical problems (such as broken clamps, hubs or leaking and cracked extension tubes) are seldom reported in the literature, even though they add to morbidity and higher health care expense. This study highlights issues related to commonly used catheters and suggests, in the interest of patient safety, a need for improved regulatory oversight in the manufacturing of CTCs.

Hemodialysis Grafts: On the Controversial Decision to Stent Venous Anastomotic Stenoses

To the Editor We read with great interest the article by Vesley et al. (1). We agree that there is no definitive answer to the controversial therapy of stenting a venous anastomotic stenosis in hemodialysis graft. The primary patency rate of 54% at 6 months with stent placement is enviable, as it certainly extends the ‘‘life-line’’ for these dialysis patients. But the question we have is: How does one deal with lesions that reappear after stenting? As discussed in this article, the endpoint of primary patency generally was a development of a significant stenosis at a new location in the circuit. How does one treat these new lesions? Should we treat forearm loop grafts and upper arm straight grafts differently? Especially, with forearm loop grafts, should these new lesions be treated with additional stents, if they fail angioplasty? Should we be stacking up stents in the proximal vein with each new lesion? Or should we try to identify patients with grafts that would be candidates for proximal fistulas. The identification of candidates for secondary fistulas could easily be accomplished during percutaneous interventions or by performing simple physical examination (2).Asif et al. recently reported the validity and success of creating secondary fistulas (3). This approach can also increase the prevalence of fistulas and is supported by the Fistula First Initiative (4). We have recently started a vascular access center and have come across patients who have multiple stents placed in the proximal vein in an attempt to maintain assisted or secondary patency. The end result is shown in Figures 1 and 2, virtually converting the entire proximal vein into a ‘‘stent-track.’’ Such a scenario has been recently reported (5). Eventually, when these grafts are abandoned, the patient loses both the proximal and distal segment of the upper extremity for future access placement. Finally, even though rare, the situation could turn into a catastrophic event if the patient were to develop stent-related infection (6). A multi-center prospective trial comparing stent versus surgical revision (at least when lesions recur after initial stent deployment) may possibly give us a better insight into this very crucial issue.