Jennifer M MacRae

The University of Calgary, Calgary, Alberta, Canada

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Publications (41)185.33 Total impact

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    ABSTRACT: Uric acid is associated with hypertension and increased renin–angiotensin system activity, although this relationship diminishes after chronic exposure to high levels. Uric acid is more strongly associated with poor outcomes in women compared to men, although whether this is due to a sex-specific uric acid-mediated pathophysiology or reflects sex differences in baseline uric acid levels remains unknown. We examined the association between uric acid and vascular measures at baseline and in response to angiotensin-II challenge in young healthy humans. Fifty-two subjects (17 men, 35 premenopausal women) were studied in high-salt balance. Serum uric acid levels were significantly higher in men compared to women (328 ± 14 μmol/L vs. 248 ± 10 μmol/L, P < 0.001), although all values were within normal sex-specific range. Men demonstrated no association between uric acid and blood pressure, either at baseline or in response to angiotensin-II. In stark contrast, a significant association was observed between uric acid and blood pressure at baseline (systolic blood pressure, P = 0.005; diastolic blood pressure, P = 0.02) and in response to angiotensin-II (systolic blood pressure, P = 0.035; diastolic blood pressure, P = 0.056) in women. However, this sex difference lost significance after adjustment for baseline uric acid. When all subjects were stratified according to high (>300 μmol/L) or low (≤300 μmol/L) uric acid levels, only the low uric acid group showed a positive association between uric acid and measures of vascular tone at baseline and in response to angiotensin-II. Differences in uric acid-mediated outcomes between men and women likely reflect differences in exposure to increased uric acid levels, rather than a sex-specific uric acid-mediated pathophysiology.
    Physiological Reports. 12/2014; 2(12).
  • Jennifer M MacRae
    American journal of kidney diseases : the official journal of the National Kidney Foundation. 10/2014; 64(4):658.
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    ABSTRACT: Patients with end-stage kidney disease (ESKD) have a high rate of mortality and specifically an increased risk of sudden cardiac death (SCD). Impaired cardiac autonomic tone is associated with elevated risk of SCD. Moreover, patients with ESKD are often vitamin D deficient, which we have shown may be linked to autonomic dysfunction in humans. To date, it is not known whether vitamin D supplementation normalizes cardiac autonomic function in the high-risk ESKD population. The VITamin D supplementation and cardiac Autonomic tone in Hemodialysis (VITAH) randomized trial will determine whether intensive vitamin D supplementation therapies improve cardiac autonomic tone to a greater extent than conventional vitamin D supplementation regimens in ESKD patients requiring chronic hemodialysis.
    BMC Nephrology 08/2014; 15(1):129. · 1.64 Impact Factor
  • Jennifer M Macrae, Michael Copland, Mercedeh Kiaii
    Seminars in Dialysis 03/2014; 27(2):85-6. · 2.25 Impact Factor
  • Jennifer M Macrae, Sofia B Ahmed, Brenda R Hemmelgarn
    American Journal of Kidney Diseases 01/2014; 63(1):165. · 5.29 Impact Factor
  • Jennifer M. MacRae, Sofia B. Ahmed, Brenda R. Hemmelgarn
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    ABSTRACT: Background We previously have shown that buttonhole needling is associated with a reduction in hematoma and postulated that buttonhole needling may increase long-term survival of an arteriovenous fistula (AVF). The purpose of this study was to evaluate AVF survival and complications in buttonhole versus standard needling. Study Design Long-term follow up of a randomized controlled trial in which participants were randomly assigned to standard or buttonhole needling and followed up until the AVF was abandoned or the study end date. Setting & Participants 140 long-term hemodialysis patients in Calgary, Alberta. Intervention Buttonhole needling with median time of exposure to the intervention of 13.2 (IQR, 7.8-19.4) months. Outcomes & Measurements Patients were prospectively followed up for study outcomes. Median follow-up times were 17.2 (IQR, 11.9-37.8) and 19.2 (IQR, 12.5-41.0) months for standard and buttonhole needling, respectively (P = 0.2). The primary outcome was median access survival in months. Other outcomes included assisted and unassisted patency rates, rates of surgical and radiologic interventions, and time to abandonment (months) of buttonhole. Results Baseline characteristics were similar. The primary outcome, median access survival, was similar in both groups: 16.0 (IQR, 10.6-29.3) and 18.4 (IQR, 10.9-32.7) months for standard and buttonhole needling, respectively (P = 0.2). There were 7 (10.1%) and 6 (8.6%) thromboses with standard and buttonhole needling, respectively (P = 0.6). Median fistulogram rates were similar between techniques (P = 0.2 with intention-to-treat analysis). Most patients (46 of 70) abandoned buttonhole needling by a median of 11.3 (IQR, 4.8-18.2) months. Median time to first infection for buttonhole needling was 11.1 (IQR, 4.9-30.0) months. There were no infections in standard needling of AVFs. Limitations Findings are limited to patients needled by multiple hemodialysis nurses and not applicable to self-needlers. Conclusions AVFs with buttonhole needling did not have improved survival. The lack of survival benefit and higher risk of infection should be noted when promoting buttonhole needling.
    American Journal of Kidney Diseases 01/2014; 63(4):636–642. · 5.29 Impact Factor
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    ABSTRACT: Abstract Vitamin D deficiency is associated with increased arterial stiffness. We sought to clarify the influence of vitamin D in modulating angiotensin II-dependent arterial stiffness. Thirty-six healthy subjects (33 ± 2 years, 67% female, mean 25-hydroxyvitamin D 69 ± 4 nmol/L) were studied in high salt balance. Arterial stiffness, expressed as brachial pulse wave velocity (bPWV) and aortic augmentation index (AIx), was measured by tonometry at baseline and in response to angiotensin II infusion (3 ng/kg/min × 30 min then 6 ng/kg/min × 30 min). The primary outcome was change in bPWV after an angiotensin II challenge. Results were analyzed according to plasma 25-hydroxyvitamin D status: deficient (<50 nmol/L) and sufficient (≥50 nmol/L). There were no differences in baseline arterial stiffness between vitamin D deficient (25-hydroxyvitamin D 40 ± 2 nmol/L) and sufficient (25-hydroxyvitamin D 80 ± 4 nmol/L) groups. Compared with sufficient vitamin D status, vitamin D deficiency was associated with a decreased arterial response to angiotensin II challenge (Δbrachial pulse wave velocity: 0.48 ± 0.44 m/s versus 1.95 ± 0.22 m/s, p = 0.004; Δaortic augmentation index: 9.4 ± 3.4% versus 14.2 ± 2.7%, p = 0.3), which persisted for brachial pulse wave velocity response after adjustment for covariates (p = 0.03). Vitamin D deficiency is associated with increased arterial stiffness in healthy humans, possibly through an angiotensin II-dependent mechanism.
    Clinical and Experimental Hypertension 10/2013; · 1.28 Impact Factor
  • Rajneet K Atkar, Jennifer M Macrae
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    ABSTRACT: There has been increased interest in buttonhole cannulation, particularly in the last 5 years, because of the perceived benefit of improved fistula outcomes. The recent randomized trials provide for a timely review regarding the potential benefit and possible harms of the buttonhole technique. The majority of observational studies report a reduction in pain with buttonhole; however, after reviewing the results from five randomized trials, buttonhole cannulation, when delivered by a nurse, does not appear to be less painful than rope ladder cannulation. Studies consistently report fewer infiltrations, reduced hematoma and a reduction of aneurysm formation with buttonhole. These benefits must be balanced against the increased risk of infection and septic complications seen with buttonhole cannulation. On the basis of the current studies, buttonhole, when done in an in-center environment with many rotating staff nurses, is a complex and challenging technique. Buttonhole technique might be best utilized for difficult or limited fistula needling sites. An infection prevention education campaign along with regular audits regarding localized infections and bacteremias should be a critical part of any program which uses buttonhole cannulation. A randomized trial comparing buttonhole to rope ladder needling among home hemodialysis or self-needled patients should be the focus for future research.
    Current Opinion in Nephrology and Hypertension 09/2013; · 3.96 Impact Factor
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    ABSTRACT: Objective: Sex influences the cardiorenal risk associated with body mass index (BMI). We sought to investigate the role of the renin-angiotensin-aldosterone system in adiposity-mediated cardiorenal risk profiles in healthy, non-obese men and women. Design and Methods: Systemic and renal hemodynamic responses to angiotensin-II (AngII) as a function of BMI, waist and hip circumference, waist-hip ratio, as well as fat and lean mass were measured in 18 men and 25 women in high-salt balance, stratified by BMI (<25kg/m(2) (ideal body weight (IBW)) vs. ≥25kg/m(2) (overweight)). Results: In men (n=7) and women (n=14) of IBW, BMI was not associated with the systolic blood pressure (SBP) response to AngII. In contrast, overweight men (29±2kg/m(2) ) demonstrated a progressively more blunted vasoconstrictor SBP response to AngII challenge as BMI increased (p=0.007), even after adjustment for covariates. Women maintained the same relationship between BMI and the SBP response to AngII irrespective of weight status (p=0.2, IBW vs. overweight women). Compared to BMI, other adiposity measures showed similar associations to systemic AngII responsiveness in men but not in women. Increasing BMI was associated with a blunted renovasoconstrictor response to AngII in all subjects, but was more pronounced in men. Conclusion: Sex influences the effect of adiposity on vascular angiotensin-responsiveness.
    Obesity 08/2013; · 3.92 Impact Factor
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    ABSTRACT: Vascular access complications are a major cause of morbidity in patients undergoing hemodialysis, and determining how the risks of different complications vary over the life of an access may benefit the design of prevention strategies. We used data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) to assess the temporal profiles of risks for infectious and noninfectious complications of fistulas, grafts, and tunneled catheters in incident hemodialysis patients. We used longitudinal data to model time from access placement or successful treatment of a previous complication to subsequent complication and considered multiple accesses per patient and repeated access complications using baseline and time-varying covariates to obtain adjusted estimates. Of the 7769 incident patients identified, 7140 received at least one permanent access. During a median follow-up of 14 months (interquartile range, 7-22 months), 10,452 noninfectious and 1131 infectious events (including 551 hospitalizations for sepsis) occurred in 112,085 patient-months. The hazards for both complication types declined over time in all access types: They were 5-10 times greater in the first 3-6 months than in later periods after access placement or a remedial access-related procedure. The hazards declined more quickly with fistulas than with grafts and catheters (P<0.001; Weibull regression). These data indicate that risks for noninfectious and infectious complications of the hemodialysis access decline over time with all access types and suggest that prevention strategies should target the first 6 months after access placement or a remedial access-related procedure.
    Journal of the American Society of Nephrology 07/2013; · 8.99 Impact Factor
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    ABSTRACT: Practices in vascular access management with intensive hemodialysis may differ from those used in conventional hemodialysis. We conducted a systematic review to inform clinical practice guidelines for the provision of intensive hemodialysis. Adult patients receiving maintenance (>3 months) intensive hemodialysis (frequent [≥5 hemodialysis treatments per week] and/or long [>5.5 hours per hemodialysis treatment]). We searched EMBASE and MEDLINE (1990-2011) for randomized and observational studies. We also searched conference proceedings (2007-2011). (1) Central venous catheter (CVC) versus arteriovenous (AV) access, (2) buttonhole versus rope-ladder cannulation, (3) topical antimicrobial cream versus none in buttonhole cannulation, and (4) closed connector devices among CVC users. Access-related infection, survival, hospitalization, patency, access survival, intervention rates, and quality of life. We included 23, 7, and 5 reports describing effectiveness by access type, buttonhole cannulation, and closed connector device, respectively. No study directly compared CVC with AV access. On average, bacteremia and local infection rates were higher with CVC compared with AV access. Access intervention rates were higher with more frequent hemodialysis, but access survival did not differ. Buttonhole cannulation was associated with bacteremia rates similar to those seen with CVCs in some series. Topical mupirocin seemed to attenuate this effect. No direct comparisons of closed connector devices versus standard luer-locking devices were found. Low rates of actual or averted (near misses) air embolism and bleeding were reported with closed connector devices. Overall, evidence quality was very low. Limited direct comparisons addressing main review questions, small sample sizes, selective outcome reporting, publication bias, and residual confounding were major factors. This review highlights several differences in the management of vascular access in conventional and intensive hemodialysis populations. We identify a need for standardization of vascular access outcome reporting and a number of priorities for future research.
    American Journal of Kidney Diseases 07/2013; 62(1):112-31. · 5.29 Impact Factor
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    ABSTRACT: BACKGROUND: Patients treated with conventional hemodialysis (HD) develop disorders of mineral metabolism that are associated with increased morbidity and mortality. More frequent and longer HD has been associated with improvement in hyperphosphatemia that may improve outcomes. STUDY DESIGN: Systematic review and meta-analysis to inform the clinical practice guideline on intensive dialysis for the Canadian Society of Nephrology. SETTING & POPULATION: Adult patients receiving outpatient long (≥5.5 hours/session; 3-4 times per week) or long-frequent (≥5.5 hours/session, ≥5 sessions per week) HD. SELECTION CRITERIA FOR STUDIES: We included clinical trials, cohort studies, case series, case reports, and systematic reviews. INTERVENTIONS: Dialysate calcium concentration ≥1.5 mmol/L and/or phosphate additive. OUTCOMES: Fragility fracture, peripheral arterial and coronary artery disease, calcific uremic arteriolopathy, mortality, intradialytic hypotension, parathyroidectomy, extraosseous calcification, markers of mineral metabolism, diet liberalization, phosphate-binder use, and muscle mass. RESULTS: 21 studies were identified: 2 randomized controlled trials, 2 reanalyses of data from the randomized controlled trials, and 17 observational studies. Dialysate calcium concentration ≥1.5 mmol/L for patients treated with long and long-frequent HD prevents an increase in parathyroid hormone levels and a decline in bone mineral density without causing harm. Both long and long-frequent HD were associated with a reduction in serum phosphate level of 0.42-0.45 mmol/L and a reduction in phosphate-binder use. There was no direct evidence to support the use of a dialysate phosphate additive. LIMITATIONS: Almost all the available information is related to changes in laboratory values and surrogate outcomes. CONCLUSIONS: Dialysate calcium concentration ≥1.5 mmol/L for most patients treated with long and long-frequent dialysis prevents an increase in parathyroid hormone levels and decline in bone mineral density without increased risk of calcification. It seems prudent to add phosphate to the dialysate for patients with a low predialysis phosphate level or very low postdialysis phosphate level until more evidence becomes available.
    American Journal of Kidney Diseases 04/2013; · 5.29 Impact Factor
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    ABSTRACT: Intensive (longer and more frequent) hemodialysis has emerged as an alternative to conventional hemodialysis for the treatment of patients with end-stage renal disease. However, given the differences in dialysis delivery and models of care associated with intensive dialysis, alternative approaches to patient management may be required. The purpose of this work was to develop a clinical practice guideline for the Canadian Society of Nephrology. We applied the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach for guideline development and performed targeted systematic reviews and meta-analysis (when appropriate) to address prioritized clinical management questions. We included studies addressing the treatment of patients with end-stage renal disease with short daily (≥5 days per week, <3 hours per session), long (3-4 days per week, ≥5.5 hours per session), or long-frequent (≥5 days per week, ≥5.5 hours per session) hemodialysis. We included clinical trials and observational studies with or without a control arm (1990 and later). Based on a prioritization exercise, 6 interventions of interest included optimal vascular access type, buttonhole cannulation, antimicrobial prophylaxis for buttonhole cannulation, closed connector devices, and dialysate calcium and dialysate phosphate additives for patients receiving intensive hemodialysis. We developed 6 recommendations addressing the interventions of interest. Overall quality of the evidence was very low and all recommendations were conditional. We provide detailed commentaries to guide in shared decision making. The main limitation was the very low overall quality of evidence that precluded strong recommendations. Most included studies were small single-arm observational studies. Three randomized controlled trials were applicable, but provided only indirect evidence. Published information for patient values and preference was lacking. In conclusion, we provide 6 recommendations for the practice of intensive hemodialysis. However, due to very low-quality evidence, all recommendations were conditional. We therefore also highlight priorities for future research.
    American Journal of Kidney Diseases 04/2013; · 5.29 Impact Factor
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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. · 8.99 Impact Factor
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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; · 3.37 Impact Factor
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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. · 5.07 Impact Factor
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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; · 2.02 Impact Factor
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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
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    ABSTRACT: 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. To determine the prevalence and etiology of thrombocytopenia in hemodialysis populations of 2 Canadian provinces (British Columbia and Alberta). 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. 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%. 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). 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.
    JAMA The Journal of the American Medical Association 10/2011; 306(15):1679-87. · 29.98 Impact Factor
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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. · 1.64 Impact Factor

Publication Stats

493 Citations
185.33 Total Impact Points

Institutions

  • 2006–2014
    • The University of Calgary
      • • Department of Medicine
      • • Section of Nephrology
      Calgary, Alberta, Canada
    • London Health Sciences Centre
      • Division of Nephrology
      London, Ontario, Canada
  • 2012
    • University of Saskatchewan
      Saskatoon, Saskatchewan, Canada
  • 2004–2011
    • University of British Columbia - Vancouver
      • Division of Nephrology
      Vancouver, British Columbia, Canada
  • 2005
    • The University of Western Ontario
      • Division of Nephrology
      London, Ontario, Canada