Medicine (Austin & Northern Health) - Research Publications
Permanent URI for this collection
Search Results
1 - 5 of 5
-
ItemTaking the challenge: A protocolized approach to optimize Pneumocystis pneumonia prophylaxis in renal transplant recipients(WILEY, 2018-02)While trimethoprim-sulfamethoxazole is considered first-line therapy for Pneumocystis pneumonia prevention in renal transplant recipients, reported adverse drug reactions may limit use and increase reliance on costly and less effective alternatives, often aerosolized pentamidine. We report our experience implementing a protocolized approach to trimethoprim-sulfamethoxazole adverse drug reaction assessment and rechallenge to optimize prophylaxis in this patient cohort. We retrospectively reviewed 119 patients receiving Pneumocystis pneumonia prophylaxis prior to and after protocol implementation. Forty-two patients (35%) had 48 trimethoprim-sulfamethoxazole adverse drug reactions documented either at baseline or during the prophylaxis period, of which 83% were non-immune-mediated and 17% were immune-mediated. Significantly more patients underwent trimethoprim-sulfamethoxazole rechallenge after protocol implementation (4/22 vs 23/27; P = .0001), with no recurrence of adverse drug reactions in 74%. In those who experienced a new or recurrent reaction (26%), all were mild and self-limiting with only 1 recurrence of an immune-mediated reaction. After protocol implementation, aerosolized pentamidine-associated costs were reduced. The introduction of a standard approach to trimethoprim-sulfamethoxazole rechallenge in the context of both prior immune and non-immune-mediated reactions was safe and successful in improving the uptake of first-line Pneumocystis pneumonia prophylaxis in renal transplant recipients.
-
ItemDiagnostic application of kidney allograft-derived absolute cell-free DNA levels during transplant dysfunction(WILEY, 2019-04)Graft-derived cell-free DNA (donor-derived cell-free DNA) is an emerging marker of kidney allograft injury. Studies examining the clinical validity of this biomarker have previously used the graft fraction, or proportion of total cell-free DNA that is graft-derived. The present study evaluated the diagnostic validity of absolute measurements of graft-derived cell-free DNA, as well as calculated graft fraction, for the diagnosis of graft dysfunction. Plasma graft-derived cell-free DNA, total cell-free DNA, and graft fraction were correlated with biopsy diagnosis as well as individual Banff scores. Sixty-one samples were included in the analysis. For the diagnosis of antibody mediated rejection, the receiver-operator characteristic area under the curves of graft-derived cell-free DNA and graft fraction were 0.91 (95% CI 0.82-0.98) and 0.89 (95% CI 0.79-0.98), respectively. Both measures did not diagnose borderline or type 1A cellular mediated rejection. Graft fraction was associated with a broader range of Banff lesions, including lesions associated with cellular mediated rejection, while graft-derived cell-free DNA appeared more specific for antibody mediated rejection. Limitations of this study include a small sample size and lack of a validation cohort. The capacity for absolute quantification, and lower barriers to implementation of this methodology recommend it for further study.
-
ItemEffect of haemodialysis and residual renal function on serum levels of galectin-3, B-type natriuretic peptides and cardiac troponin T(WILEY, 2018-12)AIM: Levels of plasma markers of myocardial fibrosis (galectin-3), stretch (B-type natriuretic peptide (BNP)) and injury (high-sensitivity troponin T (hs-TnT)) are affected by haemodialysis, residual renal function (RRF) and cardiac pathology. We aimed to determine the association of RRF, urine output and haemodialysis itself on cardiac biomarkers in haemodialysis patients. METHODS: Adult haemodialysis patients underwent venesection pre- and post-haemodialysis then echocardiography and inter-dialytic urine collection to calculate RRF (mL/min per 1.73m2 ) and urine output (mL/day). Galectin-3, BNP-32, NT-ProBNP and hs-TnT levels were compared across tertiles of echocardiographic parameters, RRF and urine output using the non-parametric test for trend across ordered groups. RESULTS: Twenty-three patients (17 male) with mean age 67.7±13.8 years and median (interquartile range) dialysis duration 13.6 (9.8-19.1) months participated. Galectin-3 was substantially lower following haemodialysis: 55 ng/mL (47-70) versus 23 ng/mL (19-27, P < 0.001), but other biomarkers changed little. By increasing RRF tertile, post-dialysis galectin-3 was 32.6 ng/mL (23.7-36.6), 21.9 ng/mL (19.0-23.2) and 19.0 ng/mL (16.9-21.0, P = 0.001); NT-ProBNP was 10 192 ng/L (2303-21 504), 2037 ng/L (1224-10 795) and 1481 ng/L (172-2890, P = 0.016). Results were similar for daily urine volume, but measured echocardiographic parameters were not associated with biomarker concentrations. CONCLUSION: Plasma concentration of galectin-3 is reduced by the haemodialysis procedure. Lower RRF and urine volume are strongly associated with higher levels of galectin-3 and NT-Pro-BNP. These associations are important to the clinical interpretation of these biomarker levels in haemodialysis patients.
-
ItemNo Preview AvailableTemporal Trajectory of B-Type Natriuretic Peptide in Patients with CKD Stages 3 and 4, Dialysis, and Kidney Transplant(AMER SOC NEPHROLOGY, 2014-06-06)BACKGROUND AND OBJECTIVES: B-type natriuretic peptide (BNP) concentration predicts outcome in patients undergoing dialysis. Because survival and cardiovascular risk change across the CKD continuum, serial changes in BNP were compared in patients at different CKD stages and after kidney transplantation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Patients with CKD stages 3 and 4 (CKD 3-4), dialysis patients, and kidney transplant recipients (KTRs) from one center had two measurements of BNP taken a median of 161 days apart in 2003-2004 and were followed until July 2012. Both BNP-32 (Triage BNP; Biosite Diagnostics) and NT-BNP-76 (proBNP; Roche Diagnostics) were assayed. The interaction between change in log-transformed BNP concentration over time and patient group was tested by fitting regression models on panel data with random effects. Survival after the second measurement was compared by tertile of change in BNP. RESULTS: Patients with CKD 3-4 (n=48), dialysis patients (n=102), and KTRs (n=73) were followed for a median of 5.7, 4.8, and 5.9 years, respectively. The interaction between patient group and BNP measurements over time was significant for NT-BNP-76 (P<0.001) and BNP-32 (P<0.01). Median NT-BNP-76 increased in dialysis patients and those with CKD 3-4 from 3850 pg/ml (interquartile range [IQR], 1776-12,323 pg/ml) to 18,830 pg/ml (IQR, 6114-61,009 pg/ml; P<0.001) and from 698 pg/ml (IQR, 283-2922 pg/ml) to 2529 pg/ml (IQR, 347-9277 pg/ml; P=0.002), respectively. Change was not significant for KTRs or comparisons made with BNP-32. Survival rate was significantly lower for patients with the highest tertile of change in NT-BNP-76 among patients with CKD 3-4 (P=0.02), but not in the dialysis or KTR groups. In 11 patients who received a kidney transplant during the study, median NT-BNP-76 decreased from 9607 pg/ml (IQR, 2292-31,282 pg/ml) to 457 pg/ml (IQR, 203-863 pg/ml) after transplant (P<0.01). CONCLUSIONS: The temporal trajectory of BNP differs between dialysis patients and those with CKD 3-4 and KTRs. This has important implications for the development of BNP-guided management strategies in CKD.
-
ItemNo Preview AvailableAngiotensin-converting enzyme 2 activity in patients with chronic kidney disease(OXFORD UNIV PRESS, 2013-09)BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) is a novel regulator of the renin-angiotensin system that counteracts the adverse effects of angiotensin II. In heart failure patients, elevated plasma ACE2 activity predicted adverse events and greater myocardial dysfunction. We aimed to describe plasma ACE2 activity and its clinical associations in patients with kidney disease. METHODS: Patients recruited from a single centre comprised of chronic kidney disease Stage III/IV (CKD), haemodialysis patients and kidney transplant recipients (KTRs). Plasma ACE2 enzyme activity was measured using a fluorescent substrate assay in plasma, collected at baseline and stored at -80°C. Linear regression was performed in both males and females separately to determine the covariates associated with log-transformed ACE2. RESULTS: The median (interquartile range) plasma ACE2 activity in pmol/mL/min was 15.9 (8.4-26.1) in CKD (n = 59), 9.2 (3.9-18.2) in haemodialysis (n = 100) and 13.1 (5.7-21.9) in KTR (n = 80; P < 0.01). In male haemodialysis patients, ACE2 activity was 12.1 (6.8-19.6) compared with 4.4 (2.5-10.3) in females (P < 0.01). Log-transformed ACE2 plasma activity was associated with post-haemodialysis systolic blood pressure in females [β-coefficient 0.04, 95% confidence interval (95% CI) 0.01-0.06, P = 0.006]. In males, log-transformed ACE2 plasma activity was associated with B-type natriuretic peptide (β-coefficient 0.39, 95% CI 0.19-0.60, P < 0.001). Plasma ACE2 activity was not associated with mortality. CONCLUSIONS: Plasma ACE2 activity is reduced in haemodialysis patients compared with CKD patients, and in female haemodialysis patients compared with male. The different associations of plasma ACE2 activity between male and female haemodialysis patients indicate that the role of ACE2 in cardiovascular disease may differ by gender.