Publications (20)77.65 Total impact
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Article: Associations between Hemodialysis Access Type and Clinical Outcomes: A Systematic Review.
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ABSTRACT: Clinical practice guidelines recommend an arteriovenous fistula as the preferred vascular access for hemodialysis, but quantitative associations between vascular access type and various clinical outcomes remain controversial. We performed a systematic review of cohort studies to evaluate the associations between type of vascular access (arteriovenous fistula, arteriovenous graft, and central venous catheter) and risk for death, infection, and major cardiovascular events. We searched MEDLINE, EMBASE, and article reference lists and extracted data describing study design, participants, vascular access type, clinical outcomes, and risk for bias. We identified 3965 citations, of which 67 (62 cohort studies comprising 586,337 participants) met our inclusion criteria. In a random effects meta-analysis, compared with persons with fistulas, those individuals using catheters had higher risks for all-cause mortality (risk ratio=1.53, 95% CI=1.41-1.67), fatal infections (2.12, 1.79-2.52), and cardiovascular events (1.38, 1.24-1.54). Similarly, compared with persons with grafts, those individuals using catheters had higher risks for mortality (1.38, 1.25-1.52), fatal infections (1.49, 1.15-1.93), and cardiovascular events (1.26, 1.11-1.43). Compared with persons with fistulas, those individuals with grafts had increased all-cause mortality (1.18, 1.09-1.27) and fatal infection (1.36, 1.17-1.58), but we did not detect a difference in the risk for cardiovascular events (1.07, 0.95-1.21). The risk for bias, especially selection bias, was high. In conclusion, persons using catheters for hemodialysis seem to have the highest risks for death, infections, and cardiovascular events compared with other vascular access types, and patients with usable fistulas have the lowest risk.Journal of the American Society of Nephrology 02/2013; 24(3):465-73. · 9.66 Impact Factor -
Article: Pneumatic compression devices during hemodialysis: a randomized crossover trial.
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ABSTRACT: Background Maintenance of central blood volume (CBV) is essential for hemodynamic stability during hemodialysis (HD), though preservation of CBV is poorly understood. Pneumatic compression devices (PCDs) during HD may help maintain CBV.Methods We performed a randomized, crossover trial to determine the effect of PCDs on CBV during HD. Patients underwent two consecutive mid-week HD sessions, randomized to begin the first session either with or without PCDs [stratified by intradialytic hypotension (IDH)-prone status]. The primary outcome was change in CBV during HD. The secondary outcomes were change in other hemodynamic and volume status parameters.ResultsFifty-one patients (median age 65 years, 75% male, 22% IDH-prone) were randomized; forty-six completed the study. During HD, the median change in CBV for PCD and control sessions was -0.08 versus -0.05 L (P = 0.62). There was no difference in the change in cardiac output (CO) (-0.63 versus -0.49 L/min, P = 0.78) or systemic vascular resistance (SVR) (+1.30 versus +1.55mmHg/L/min, P = 0.67) for PCDs versus control. Based on the bioimpedance measurements, patients were not volume overloaded pre-dialysis. There was a greater reduction in total body water (TBW) (-2.6 versus -2.3 L, P = 0.05) and intracellular fluid (ICF) volume (-1.3 versus -1.1 L, P = 0.03), and no difference in change in the extracellular fluid (ECF) volume (1.3 versus 1.2 L, P = 0.09) with PCDs versus control. Similar results were observed in IDH-prone patients.Conclusions Compared with standard of care, PCDs have no effect on intradialytic hemodynamic parameters, including CBV, although they may allow greater capacity for fluid removal. Further studies are required to better understand physiological and hemodynamic changes in patients during HD.Nephrology Dialysis Transplantation 11/2012; · 3.40 Impact Factor -
Article: A randomized trial comparing buttonhole with rope ladder needling in conventional hemodialysis patients.
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ABSTRACT: Buttonhole needling is reported to be associated with less pain than standard needling. The purpose of this study was to compare patient perceived pain and fistula complications in buttonhole and standard needling. In this study, 140 conventional hemodialysis patients were randomly assigned to buttonhole or standard needling. The primary outcome was patient perceived pain with needling at 8 weeks. Fistula complications of hematoma, bleeding postdialysis, and infection were tracked. Median pain score at 8 weeks using a visual analog scale from 0 to 10 cm was similar for standard and buttonhole needling (1.2 [0.4-2.4] versus 1.5 [0.5-3.4]; P=0.57). Rate of hematoma formation in standard needling was higher (436 versus 295 of 1000 hemodialysis sessions; P=0.03). Rate of no bleeding postdialysis was 23.6 and 28.3 per 1000 in standard and buttonhole needling, respectively (P=0.40). Rate of localized signs of infection in standard versus buttonhole needling was 22.4 versus 50 per 1000 (P=0.003). There was one episode of Staphylococcal aureus bacteremia during the 8 weeks with buttonhole needling and no episodes with standard needling (P=1.00). Within 12 months of follow-up, another two buttonhole needling episodes developed S. aureus bacteremia, and nine buttonhole needling episodes had needling site abscesses requiring intravenous antibiotics versus zero standard needling episodes (P=0.003). Patients had no difference in pain between buttonhole and standard needling. Although fewer buttonhole needling patients developed a hematoma, there was an increased risk of bacteremia and localized signs of infection. Routine use of buttonhole needling is associated with increased infection risk.Clinical Journal of the American Society of Nephrology 07/2012; 7(10):1632-8. · 5.23 Impact Factor -
Article: Hemodialysis prescription education decreases intradialytic hypotension.
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ABSTRACT: Background: Intradialytic hypotension (IDH) is associated with increased morbidity and mortality. We studied the impact of an education program and hemodialysis (HD) prescription optimization on the frequency of IDH. Methods: We compared chronic HD patients during 2 retrospective time periods: a control period and the study period which occurred after 2 months of physician education and HD prescription optimization. Primary study outcomes were the frequency of HD sessions complicated by IDH, and the prevalence of IDH-prone patients. Results: There were 91 and 82 patients in the control and study periods, respectively. In the study period, 11% (115/1107) of HD sessions were complicated by IDH vs. 17% (189/1103) in the control period (p = 0.0002). There was a decreased odds ratio for IDH in the study period compared with control (odds ratio [OR] = 0.59; 95% confidence interval [95% CI], 0.40-0.86; p = 0.007). Compared with control, more patients in the study period were prescribed at least 2 preventative strategies (42% vs. 61%, p = 0.02), including increased use of cool dialysate (55% vs. 89%, p<0.001). Cool dialysate reduced the odds of IDH by 50% (OR = 0.50; 95% CI, 0.30-0.86; p = 0.012). Conclusion: HD prescription education with concurrent use of multiple preventative strategies is associated with a significant decrease in IDH.Journal of nephrology 06/2012; · 1.65 Impact Factor -
Article: Increased urinary protein excretion in the "normal" range is associated with increased renin-angiotensin system activity.
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ABSTRACT: Increased levels of albuminuria and proteinuria, both linked to augmented renin-angiotensin system (RAS) activity, are associated with adverse kidney and cardiovascular events. However, the relationship between variations in urinary albumin excretion (UAE) and total protein excretion (UTPE) in the normal range and RAS activity is unclear. We examined the association between UAE and UTPE and the hemodynamic response to angiotensin II (ANG II) challenge, a well-accepted indirect measure of RAS activity, in healthy individuals with normal UAE and UTPE. Forty subjects (15 men, 25 women; age 38 ± 2 yr; UAE, 3.32 ± 0.55 mg/day; UTPE, 56.8 ± 3.6 mg/day) were studied in high-salt balance. Blood pressure (BP), arterial stiffness determined by applanation tonometry, and circulating RAS components were measured at baseline and in response to graded ANG II infusion. The primary outcome was the BP response to ANG II challenge at 30 and 60 min. UAE was associated with a blunted diastolic BP response to ANG II infusion (30 min, P = 0.005; 60 min, P = 0.17), a relationship which remained even after adjustment (30 min, P < 0.001; 60 min, P = 0.035). Similar results were observed with UTPE (30 min, P = 0.031; 60 min, P = 0.001), even after multivariate analysis (30 min, P = 0.008; 60 min, P = 0.001). Neither UAE nor UTPE was associated with systolic BP, circulating RAS components, or arterial stiffness responses to ANG II challenge. Among healthy individuals with UAE and UTPE in the normal range, increased levels of these measures were independently associated with a blunted diastolic BP response to ANG II, indicating increased vascular RAS activity, which is known to be deleterious to both renal and cardiac function.AJP Renal Physiology 11/2011; 302(5):F526-32. · 4.42 Impact Factor -
Article: Evaluation of an electronic warfarin nomogram for anticoagulation of hemodialysis patients.
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ABSTRACT: Warfarin nomograms to guide dosing have been shown to improve control of the international normalized ratio (INR) in the general outpatient setting. However, the effectiveness of these nomograms in hemodialysis patients is unknown. We evaluated the effectiveness of anticoagulation using an electronic warfarin nomogram administered by nurses in outpatient hemodialysis patients, compared to physician directed therapy. Hemodialysis patients at any of the six outpatient clinics in Calgary, Alberta, treated with warfarin anticoagulation were included. Two five-month time periods were compared: prior to and post implementation of the nomogram. The primary endpoint was adequacy of anticoagulation (proportion of INR measurements within range ± 0.5 units). Overall, 67 patients were included in the pre- and 55 in the post-period (with 40 patients in both periods). Using generalized linear mixed models, the adequacy of INR control was similar in both periods for all range INR levels: in detail, range INR 1.5 to 2.5 (pre 93.6% (95% CI: 88.6% - 96.5%); post 95.6% (95% CI: 89.4% - 98.3%); p = 0.95); INR 2.0 to 3.0 (pre 82.2% (95% CI: 77.9% - 85.8%); post 77.4% (95% CI: 72.0% - 82.0%); p = 0.20); and, INR 2.5 to 3.5 (pre 84.3% (95% CI: 59.4% - 95.1%); post 66.8% (95% CI: 39.9% - 86.0%); p = 0.29). The mean number of INR measurements per patient decreased significantly between the pre- (30.5, 95% CI: 27.0 - 34.0) and post- (22.3, 95% CI: 18.4 - 26.1) (p = 0.003) period. There were 3 bleeding events in each of the periods. An electronic warfarin anticoagulation nomogram administered by nurses achieved INR control similar to that of physician directed therapy among hemodialysis patients in an outpatient setting, with a significant reduction in frequency of testing. Future controlled trials are required to confirm the efficacy of this nomogram.BMC Nephrology 09/2011; 12:46. · 2.18 Impact Factor -
Article: Morphometric and biological characterization of biofilm in tunneled hemodialysis catheters.
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ABSTRACT: Bacterial biofilm formation on hemodialysis tunneled cuffed catheters is under-recognized. We studied biofilm characteristics in patients with and without catheter-related bloodstream infection, accounting for catheter locking solution (citrate 4% or heparin 1:1,000). Prospective observational study. 30 HD patients for whom the tunneled cuffed catheter was removed for either noninfectious reasons (n = 19) or bacteremia (n = 11). Bacteremia and catheter locking solution. Bacteria density in the biofilm, catheter luminal surface covered by biofilm, biofilm thickness, and exopolysaccharide content. Biofilm was present in all catheters. Overall, bacteria density, catheter surface coverage, biofilm thickness, and exopolysaccharide content were significantly higher in catheters from patients with bacteremia (5.3 [95% CI, 3.4-7.2] colony-forming unit [CFU]/mL; 47% [95% CI, 34%-60%]; 41 [95% CI, 26-55] μm; and 29.4% [95% CI, 20.1%-38.6%], respectively) than from patients without bacteremia (3.7 [95% CI, 3.6-3.8] CFU/mL; 17% [95% CI, 16%-19%]; 8.6 [95% CI, 7.3-9.8] μm; and 5.3% [95% CI, 3.7%-6.8%], respectively). However, all biofilm parameters were lower in catheters from patients with bacteremia when citrate was used as locking agent. Furthermore, bacteria density (0.08 [95% CI, 0.02-0.13] CFU/mL/3 cm), biofilm thickness (1.4 [95% CI, 0.8-2.1] μm/3 cm), and surface coverage (2.2% [95% CI, 1.8%-2.7%]/3 cm) decreased across the length of the catheter from tip to hub. Observational study design, small numbers of patients, use of prevalent catheters. Biofilms are present in all tunneled cuffed catheters. However, the extent of the biofilm varied by the presence of bacteremia and type of locking solution. This method could be used to explore preventative measures.American Journal of Kidney Diseases 03/2011; 57(3):449-55. · 5.43 Impact Factor -
Article: Suboptimal initiation of dialysis with and without early referral to a nephrologist.
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ABSTRACT: Our objective was to examine patients who initiate renal replacement therapy (RRT) at 10 representative Canadian centers, characterize their initiation as inpatient or outpatient and describe their initial type of dialysis access, duration of pre-dialysis care and clinical status at the time of dialysis initiation. We also examined the impact of an optimal dialysis start (i.e. initiated as an outpatient with an arteriovenous fistula, arteriovenous graft or peritoneal dialysis catheter) on subsequent health outcomes. Charts of consecutive incident RRT patients were identified from 1 July to 31 December 2006. Information was collected until 6 months after the initiation or until death, transplant or transfer. Three hundred and thirty-nine incident RRT patients were studied: 39.6% initiated as an inpatient; 54% started hemodialysis (HD) with a central venous catheter; 15.3% had <1 month predialysis care, while 64.6% had >1 year. Optimal starts occurred in 39.5% of patients. For HD patients, optimal starts occurred in 19.8%. Suboptimal starts were noted in patients referred <12 months prior to end-stage renal disease (44%) and in patients referred earlier (56%). The composite end point of death, transfusion or subsequent hospitalization was significantly reduced with an optimal start [hazard ratio 0.47 (95% confidence interval 0.32-0.68), P = 0.0001]. Suboptimal initiation of dialysis is common in patients referred early or late. The benefits of early referral are lost if dialysis is initiated suboptimally. There is a need to identify factors that lead to suboptimal initiation despite early referral.Nephrology Dialysis Transplantation 02/2011; 26(9):2959-65. · 3.40 Impact Factor -
Article: Utilization and outcome of 'out-of-center hemodialysis' in the United States: a contemporary analysis.
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ABSTRACT: There is increasing interest in the delivery of out-of-center hemodialysis (HD), particularly in the home setting, but little systematic information about its use and outcome in contemporary incident patients is available. Out-of-center HD was defined as HD delivered in a residential setting, mainly at home or in a long-term care facility (such as a nursing home) irrespective of the length and frequency of therapy. All-cause mortality was determined in an observational cohort study of 458,329 adult patients initiating dialysis in the United States with Medicare as a primary payer. Between 1995 and 2004, out-of-center HD was the initial modality in 1,641 (0.4%) of eligible participants, although there was significant geographic variation. Patients initiating out-of-center HD were younger, more likely to be nonwhite, had fewer comorbidities, a higher median income, and were more likely to be employed than patients initiating in-center HD or peritoneal dialysis (PD). In multivariate analysis, out-of-center HD patients had a higher overall risk of death compared to in-center HD or PD patients (HR = 1.10, 95% CI 1.04, 1.17), although the relative risk of death was lower in younger and healthier patients (HR = 0.78; 95% CI 0.61, 1.00). Out-of-center HD is not associated with a survival advantage among unselected patients initiating dialysis in the United States. These results call for better characterization of out-of-center HD in national registries, primarily to effectively compare the use, outcomes and potential benefits of home HD to standard therapies.Nephron Clinical Practice 01/2010; 116(1):c53-9. · 2.04 Impact Factor -
Article: Hemoglobin variability in nondialysis chronic kidney disease: examining the association with mortality.
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ABSTRACT: Anemia and hemoglobin (Hb) variability are associated with mortality in hemodialysis patients who are on erythropoiesis-stimulating agents (ESA). Our aim was to describe the degree of Hb variability present in nondialysis patients with chronic kidney disease (CKD), including those who were not receiving ESA, and to investigate the association between Hb variability and mortality. Hb variability was determined using 6 mo of "baseline" data between January 1, 2003, and October 31, 2005. A variety of definitions for Hb variability were examined to ensure consistency and robustness. A total of 6165 patients from 22 centers in seven countries were followed for a mean of 34.0 +/- 15.8 mo; 49% were prescribed an ESA. There was increased Hb variability with ESA use; the residual SD of Hb was 4.9 +/- 4.4 g/L in patients who were not receiving an ESA, compared with 6.8 +/- 4.8 g/L. Hb variability was associated with a small but significantly increased risk for death per g/L residual SD, irrespective of ESA use. Multivariate linear regression model explained only 11% of the total variance of Hb variability. Hb variability is increased in patients who have CKD and are receiving ESA and is associated with an increased risk for death (even in those who are not receiving ESAs). This analysis cannot determine whether Hb variability causally affects mortality. Thus, the concept of targeting Hb variability with specific agents needs to be examined within the context of factors that affect both Hb variability and mortality.Clinical Journal of the American Society of Nephrology 05/2009; 4(7):1176-82. · 5.23 Impact Factor -
Article: Oral estrogen therapy in postmenopausal women is associated with loss of kidney function.
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ABSTRACT: Women are generally protected against progressive loss of kidney function; however, this advantage seems to diminish with menopause. Because of conflicting reports on the association between use of hormone therapy and kidney function we studied 5845 women (1459 on hormone therapy and 4386 non-users) who were over 66 years of age and had at least 2 serum creatinine measurements during the 2 year study period. After adjustment for covariates, hormone use (estrogen-only, progestin-only, or both) was associated with a significant loss of estimated GFR as the primary outcome along with an increased risk of rapid loss of kidney function as the secondary outcome compared to non-users. This increased rate of loss was associated with oral but not transvaginal estrogen use. An increased cumulative dose of estrogen was also associated with a greater decline in estimated GFR. Our study shows an independent association in a dose-dependent manner of estrogen use and loss of kidney function in this elderly population.Kidney International 09/2008; 74(3):370-6. · 6.61 Impact Factor -
Article: Citrate 4% versus heparin and the reduction of thrombosis study (CHARTS).
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ABSTRACT: Citrate 4% has antithrombotic and antibacterial properties, which makes it a potentially superior alternative to heparin as an indwelling intraluminal locking agent. 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). 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). 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.Clinical Journal of the American Society of Nephrology 03/2008; 3(2):369-74. · 5.23 Impact Factor -
Article: Vascular access and cardiac disease: is there a relationship?
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ABSTRACT: Despite advances in hemodialysis technology, a stable and well functioning vascular access remains the bane of every hemodialysis patient. It is recognized that vascular access contributes to cardiovascular disease mortality through a number of mechanisms. This review describes the relationship between vascular access and cardiovascular disease by reviewing the relationships between infection risk, inflammation and cardiovascular disease, and the cardiovascular changes that occur as a consequence of vascular access. Improved understanding of these mechanisms and their interrelationship is warranted. The impact of arteriovenous fistula creation on cardiac structural and hemodynamic changes is described, as is vascular remodelling, which occurs in response to alterations in blood-flow properties. The development of central and peripheral vein stenosis is also a type of vascular remodelling and consequences of such events are not yet well understood. In addition, the contribution of vascular access to increased inflammation and atherosclerotic disease is reviewed. Finally, the hypothesis that vascular access dysfunction may be a predictor of vascular disease is explored. The relationship between vascular access and cardiac disease exists at different levels, ranging from inflammation promoting atherosclerotic disease to vascular remodelling changes of stenosis formation and left ventricular hypertrophy. Countless research opportunities abound.Current Opinion in Nephrology and Hypertension 12/2006; 15(6):577-82. · 4.33 Impact Factor -
Article: Surveillance cultures of tunneled cuffed catheter exit sites in chronic hemodialysis patients are of no benefit.
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ABSTRACT: Catheter-related infections are a major cause of morbidity and mortality in hemodialysis (HD) patients. This study evaluated the utility of surveillance swab cultures (Ssc) of tunneled cuffed catheter (TCC) exit sites as a prediction and prevention strategy for infection. A 6-month prospective-controlled trial with 94 chronic HD patients with a TCC who received monthly Ssc and were stratified by dialysis day into topical therapy based on Ssc results (Group A) or no therapy (Group B). Outcomes were exit site infection (ESI) and catheter-associated bacteremia (CAB). The overall monthly prevalence of positive Ssc was 14.9%. There was no difference in the number of positive Ssc (17.7% vs. 11.6%, p > 0.05) or ESI (19.6% vs.16.3%, p > 0.05) between Groups A and B, respectively. Catheter-associated bacteremia was higher in Group A (17.7% vs. 4.7%, p = 0.05). There were significantly more ESI in the patients treated for a positive Ssc. In Group A, the incidence of ESI was significantly higher in those treated for a positive vs. negative Ssc (55% vs. 12%, p = 0.009) and CAB rates trended higher with positive Ssc (22.2% vs. 16.7%, p > 0.05). The strategy of treating positive surveillance cultures is not beneficial. Positive Ssc do not predict the occurrence of catheter-related infection, and treatment of these cultures may lead to increased infection rates.Hemodialysis International 10/2006; 10(4):365-70. · 1.54 Impact Factor -
Article: Urea clearance in dysfunctional catheters is improved by reversing the line position despite increased access recirculation.
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ABSTRACT: Problematic or dysfunctional hemodialysis (HD) catheters are routinely reversed to achieve adequate blood flow for dialysis delivery. The purpose of the study is to determine the effect of varying blood pump speed (Qb) on access recirculation (AR), and urea clearance (K) in dysfunctional catheters in the normal and reversed positions. Nineteen HD patients with tunneled cuffed catheters (5 functional and 14 dysfunctional catheters) were included; dysfunctional catheters are defined as the inability to attain a Qb of 300 mL/min or greater on 2 consecutive HD runs. AR and K measurements were obtained systematically for each catheter in the normal and reversed positions at increasing Qbs. K was measured using the ionic dialysance technique. In functional catheters, AR in the normal position was 0% and increased to 15% +/- 13% when reversed. Dysfunctional catheters had a greater AR of 25% +/- 16% when reversed. In functional catheters, there was no evidence of an increase in AR with increasing Qb irrespective of position. Similarly, there was no relationship between increasing AR and greater Qbs (r 2 = 0.10) in dysfunctional catheters. In dysfunctional catheters, when reversed, mean K increased from 128 +/- 10 mL/min at a Qb of 200 mL/min to 157 +/- 38 mL/min at maximal Qb (P < 0.05). We show that at increasing Qbs, K is improved in both functional and dysfunctional catheters. Data from the study are used to describe a nomogram to determine minimum Qb for a dysfunctional catheter in reversed position to maximize K.American Journal of Kidney Diseases 05/2005; 45(5):883-90. · 5.43 Impact Factor -
Article: Arteriovenous fistula-associated high-output cardiac failure: a review of mechanisms.
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ABSTRACT: High-output cardiac failure can be a rare complication of high-output arteriovenous fistula. The authors present a case in which a hemodialysis patient with a high-flow arteriovenous fistula has cardiac failure that improves with fistula closure. The hemodynamic effects of a fistula are reviewed, and the hemodialysis literature regarding high-output cardiac failure is summarized. To gain insight into the problem of high-output cardiac failure, research efforts should focus on the prospective monitoring of high-access flows.American Journal of Kidney Diseases 06/2004; 43(5):e17-22. · 5.43 Impact Factor -
Article: Central vein stenosis: a common problem in patients on hemodialysis.
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ABSTRACT: 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.ASAIO Journal 51(1):77-81. · 1.39 Impact Factor -
Article: The cardiovascular effects of arteriovenous fistulas in chronic kidney disease: a cause for concern?
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ABSTRACT: Arteriovenous fistulas (AVFs) are the preferred type of vascular access, but relatively little is known regarding their effects on cardiovascular remodeling and cardiac function. The following is a review regarding the immediate and long-term complications associated with AVF creation, including the development of left ventricular hypertrophy, high-output cardiac failure, exacerbation of coronary ischemia, and the possible contribution to the development of central vein stenosis.Seminars in Dialysis 19(5):349-52. · 2.27 Impact Factor -
Article: Determining lung water volume in stable hemodialysis patients.
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ABSTRACT: Lung water (LW) reflects the water content of the lung interstitium. Because hemodialysis patients have expanded total body water (TBW) they may also have increased LW. Hypertonic saline promotes a flux of water from lung to blood, which is measured by ultrasound flow probes on hemodialysis tubing. The volume of flux is an indirect measure of LW. Our purpose was to determine the feasibility and reproducibility of LW derived with ultrasound velocity dilution, to determine the effect of ultrafiltration on LW in stable hemodialysis patients, and to compare changes in LW with fluid compartment shifts using bioimpedance. Lung water, cardiac output, total body water, and extracellular and intracellular fluid volumes were measured in 24 stable hemodialysis patients at the beginning of hemodialysis and after ultrafiltration. The LW values at the beginning of hemodialysis (298.8 +/- 90.2 ml or 3.67 +/- 1.47 ml/kg) fell during hemodialysis (250.8 +/- 55.8 ml or 3.12 +/- 0.96 ml/kg; p < 0.05), as did TBW and extracellular fluid volumes (p < 0.001). Cardiac output, cardiac index, and central blood volume also decreased significantly with ultrafiltration (p < 0.005, p < 0.005, and p < 0.01, respectively). Results showed that stable hemodialysis patients have higher specific LW values (3.67 ml/kg) than the normal population (2 ml/kg) and ultrafiltration produces a significant decline in LW values.ASAIO Journal 52(4):430-7. · 1.39 Impact Factor -
Article: Extravascular lung water and peripheral volume status in hemodialysis patients with and without a history of heart failure.
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ABSTRACT: Determining volume status in hemodialysis patients with a history of congestive heart failure (CHF) is difficult. Extravascular lung water (EVLW) may be derived from blood ultrasound velocity changes following injections of 0.9% and 5% saline. Bioimpedance spectroscopy can measure total body water (TBW) and its intracellular fluid (ICF) and extracellular fluid (ECF) compartments. We studied 29 clinically euvolemic hemodialysis patients, 12 of whom had a history of CHF. The ECF and ICF were measured before dialysis, and EVLW was measured during dialysis. Values of EVLW were similar between patients without CHF and those with CHF (3.55 ml/kg +/- 0.94 SD versus 3.88 ml/kg +/- 0.82 SD, respectively; p = NS). The ECF/ICF ratio was higher among patients with a history of CHF (1.27 +/- 0.29) than among those without such a history (1.04 +/- 0.04; p < 0.05), indicating that ECF volume overload was present in both groups, but was higher in those with a CHF history. There was a positive correlation between EVLW and ECF/ICF ratios (r = 0.54, p < 0.01). Measurements of EVLW were higher in two pulmonary edema patients ((7.95 ml/kg and 5.95 ml/kg; p < 0.05). The results of this study suggest that 1) hemodialysis patients with a history of CHF have more ECF volume overloaded than those without such a history; 2) the degree of ECF expansion is associated with increasing EVLW volume, even in patients without pulmonary edema; and 3) ECF volume expansion eventually exceeds limits and pulmonary edema occurs. These developing technologies of volume measurement may be of value in this challenging clinical area.ASAIO Journal 52(4):423-9. · 1.39 Impact Factor
Top co-authors
Top Journals
Institutions
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2012
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University of Saskatchewan
Saskatoon, Saskatchewan, Canada
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2006–2012
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The University of Calgary
- • Department of Medicine
- • Section of Nephrology
Calgary, Alberta, Canada
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2004–2006
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University of British Columbia - Vancouver
- Division of Nephrology
Vancouver, British Columbia, Canada
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2005
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The University of Western Ontario
- Division of Nephrology
London, Ontario, Canada
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