Mercedeh Kiaii

Central vein stenosis: a common problem in patients on hemodialysis.

Central vein stenosis (CVS) has been associated with subclavian (SCV) catheter insertions. The prevalence of CVS in the current era with minimal use of SCV catheters is unknown. Furthermore, the prevalence of CVS in patients with access problems has not been previously described to our knowledge. We evaluated 235 prevalent patients on hemodialysis (HD), and, of these, 133 underwent venography for access related concerns over a 14 month period. Of these 133 patients, 55 (41%) had evidence of significant CVS on venogram. Patients with CVS had a longer duration on HD (43 ± 12 months vs. 34 ± 15 months, p = 0.018) and a history of a previous HD catheter insertion (52/55 patients vs. 59/78 patients, p = 0.0039). There were only 18 patients with a subclavian catheter insertion. In those with any history of previous HD catheter insertion, multivariate analysis demonstrated that number of catheters remains a significant factor (OR 2.69, p = 0.0004) even after excluding those subclavian insertions. This study demonstrates that CVS occurs in almost half of the patients with access problems undergoing venography. We confirm the important contribution of central vein cannulation to CVS and show that, despite minimizing subclavian catheter insertion, CVS remains a relatively common occurrence. Thus further studies should attempt to determine the true incidence of this problem and ultimately address the optimal treatment strategies.

Citrate 4% versus Heparin and the Reduction of Thrombosis Study (CHARTS)

BACKGROUND AND OBJECTIVES Citrate 4% has antithrombotic and antibacterial properties, which makes it a potentially superior alternative to heparin as an indwelling intraluminal locking agent. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS Sixty-one prevalent hemodialysis (HD) patients dialyzing with a tunneled cuffed HD catheter were randomized in a pilot study to receive either heparin 5000 U/ml or citrate 4% as a locking agent after HD. The primary outcomes were the development of catheter dysfunction (defined as a blood pump speed <250 ml/min or the use of tissue plasminogen activator) and catheter-associated bacteremia. The secondary outcomes were the development of an exit-site infection or bleeding complications (either local or systemic). RESULTS Citrate had comparable catheter dysfunction episodes to heparin (13/32 [41%] cases versus 12/29 [41%] cases, respectively). There were no differences in the development of catheter-associated bacteremia (2.2/1000 catheter days citrate versus 3.3/1000 catheter days heparin group; P = 0.607) or exit-site infection (2.2/1000 catheter days for both groups). CONCLUSIONS The preliminary findings from our pilot study demonstrate that 4% citrate is effective in maintaining catheter patency and does not appear to have any increased incidence of infections. Because citrate is significantly cheaper and has a more favorable side effect profile than heparin, it can be considered a potentially better locking agent in HD catheters.

Short and long alteplase dwells in dysfunctional hemodialysis catheters.

Background:  Hemodialysis catheter dysfunction (CD) is the inability to attain adequate blood pump speeds (BPS) and is attributed to thrombus or catheter malposition; alteplase (TPA) is often given in a variety of dwell times to treat CD. The purpose of this study was to determine if TPA dwell time affects short‐ or long‐term catheter patency rates.

Use of Electron-Beam Sterilized Hemodialysis Membranes and Risk of Thrombocytopenia

CONTEXT Thrombocytopenia is not widely recognized as a potential dialyzer-related complication. Following the observation of significant thrombocytopenia among 20 patients undergoing hemodialysis in a single dialysis unit after the introduction of dialyzers sterilized by electron beam (e-beam), a larger investigation was undertaken. OBJECTIVE To determine the prevalence and etiology of thrombocytopenia in hemodialysis populations of 2 Canadian provinces (British Columbia and Alberta). DESIGN, SETTING, AND PARTICIPANTS A cohort study of patients undergoing hemodialysis in British Columbia (n = 1706) and southern Alberta (n = 425) between April 1, 2009, and November 30, 2010. Retrospective analyses of historical patient, laboratory, and dialyzer data predating conversion to e-beam dialyzers were undertaken, with prospective collection of predialysis and postdialysis platelet counts before and after the change from e-beam to non-e-beam sterilized dialyzers in September 2009. MAIN OUTCOME MEASURE Significant thrombocytopenia, defined a priori as postdialysis treatment platelet count of less than 100 × 10(3)/μL and a postdialysis decrease in platelet count of more than 15%. RESULTS Among 1706 patients undergoing hemodialysis in British Columbia, 1411 (83%) were undergoing hemodialysis with e-beam sterilized dialyzers. Of 1706 patients, 194 (11.4%; 95% CI, 9.9%-12.9%) had postdialysis platelet counts of less than 100 × 10(3)/μL; 400 (23.4%; 95% CI, 21.5%-25.5%) had postdialysis decreases in platelet counts of more than 15%; and 123 (7.2%; 95% CI, 6.0%-8.6%) met both criteria. Among 425 patients in Alberta undergoing dialysis with polysulfone, e-beam sterilized dialyzers made by a different manufacturer, 46 (10.8%; 95% CI, 8.1%-14.3%) had platelet counts of less than 100 × 10(3)/μL; 156 (32.0%; 95% CI, 27.6%-36.7%) had decreases in platelet counts of more than 15%; and 31 (7.3%; 95% CI, 5.1%-10.3%) met both criteria. In multivariable analysis adjusting for patient and dialysis history characteristics, a significant association was observed between using an e-beam sterilized dialyzer and risk of significant thrombocytopenia (odds ratio [OR], 2.52; 95% CI, 1.20-5.29; P = .02). Compared with use of e-beam sterilized dialyzers, following the change to use of non-e-beam sterilized dialyzers, among 1784 patients, significant reductions were observed in postdialysis thrombocytopenia (120 patients [6.7%; 95% CI, 5.6%-8.0%; P < .001] had platelet counts of <100 × 10(3)/μL; 167 patients [9.4%; 95% CI, 8.1%-10.8%; P < .001] had decreases in platelet counts of >15%; and 38 patients [2.1%; 95% CI, 1.5%-2.9%; P < .001] met both criteria). Using generalized estimating equation modeling for repeated data with binary outcome, after adjusting for patient characteristics, the odds of significant thrombocytopenia were higher during the use of e-beam sterilized dialyzers than with use of non-e-beam sterilized dialyzers (OR, 3.57; 95% CI, 2.54-5.04; P < .001). CONCLUSION In this cohort of patients undergoing hemodialysis in 2 Canadian provinces in 2009-2010, the use of e-beam sterilized dialyzers was associated with significant thrombocytopenia following dialysis.

Outcomes of vascular access creation prior to dialysis: building the case for early referral.

A 2-year single institution experience of the successes and complications of arteriovenous fistula (AVF) creation before dialysis initiation is reported. Study cohort: all patients who underwent AVF creation before need for dialysis (AVF group, n = 125). “Control” group: all patients with a sustained glomerular filtration rate (GFR) ≤25 ml/min and eligible for AVF creation during the same time period, but did not have an access placed before dialysis (no AVF group, n = 198). Median nephrology contact time was >12 months in both groups and mean eGFR at creation (AVF group) was 12 ml/min. In the AVF group, 72% underwent a successful first AVF creation, 11% suffered AVF thrombosis, and 17% had a nonmaturing AVF before need for dialysis. Sixty-six percent (n = 23) of these latter patients underwent a second AVF creation and 48% were mature at dialysis initiation. During the study period, 70% (n = 88, AVF group) and 61% (n = 121, no AVF group) commenced dialysis. Impressively, 72% (n = 66) of the AVF group used a mature fistula as their first dialysis access. A snapshot of “access in use” at the 6-month mark of dialysis revealed the AVF group had a higher number of patients using an AVF (81% vs. 44%) and a lower number with catheters (19% vs. 56%, respectively, p = 0.001). In conclusion, the success rate of early AVF creation is reasonable and complications when identified can be remedied without the need for a catheter, thus ultimately maximizing the use of AVF in dialysis patients.

Hemodynamic and Volume Changes during Hemodialysis

Background: Volume overload is a factor in the hypertension of hemodialysis (HD) patients. Fluid removal is therefore integral to the hemodialysis treatment. Fluid removal by hemodialysis ultrafiltration (UF) may cause intradialytic hypotension and leg cramps. Understanding blood pressure (BP) and volume changes during UF may eliminate intradialytic hypotension and cramps. Studies (S1, S2, and S3) were carried out to determine the amount and direction of changes in body fluid compartments following UF and to determine the relationships between BP, changes in blood volume (ΔBV), central blood volume (CBV), cardiac output (CO), peripheral vascular resistance (PVR) plus total body water (TBW), and intra‐ and extracellular fluid volumes (ICF, ECF) in both the whole body and body segments (arms, legs, trunk).