25 results on '"Stevens KK"'
Search Results
2. A descriptive analysis of non-human leukocyte antigens present in renal transplant donor-recipient pairs.
- Author
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Sisk LJ, Patel RK, and Stevens KK
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- Graft Rejection, Graft Survival, HLA Antigens, Humans, Kidney physiology, Renal Dialysis, Transplant Recipients, Kidney Transplantation
- Abstract
Introduction: End stage renal disease (ESRD) is the irreversible deterioration of renal function requiring renal replacement therapy by dialysis or transplant. Human leucocyte antigens (HLA) have been well examined however research still is required into the non-HLA antibodies. Antibody mediated rejection (AMR) can be seen in the absence of HLA antibodies on biopsies of patients who have received identical transplants; anti-endothelial cell antibodies may explain this. Investigation into endothelial cell antigens on donor and recipient endothelium may elucidate and stratify the degree of risk of any given transplant and may guide towards the best matched donor., Methods: Protein array analysis was carried out on 8 patient pairs using nitro-cellulose membranes and biotinylated detection antibodies. The fluorescence emitted was captured by X-Ray film and results were recorded with ImageJ software. A fold increase of more than 2 was considered to be positive., Results: 11 proteins identified had a fold increase of increase ≥2 and were present in ≥2 patient pairs which may point to potential clinical utility. Nectin2/CD112 may be measured in order analyse graft survival time in transplant recipients. Prognosticating renal failure has clinical importance and potential markers that have been identified to aid which include MEPE, CRELD2, and TIMP-4. Novel pharmacological therapies for specific biomarkers identified in this study include JAM-A, E-Selectin, CD147, Galectin-3, JAM-C, PAR-1, and TNFR2., Conclusion: Protein analysis showed differences in expression of antigens between patients with and without Chronic Kidney Disease (CKD). This information could be used at the matching stage of renal transplantation and also in the treatment of rejection episodes. The results highlight biomarkers that potentially prognosticate and pharmacological therapies that may ameliorate kidney disease and rejection in ESRD and transplant recipients., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2021
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3. Ascorbic acid lowers central blood pressure and asymmetric dimethylarginine in chronic kidney disease.
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Gillis K, Stevens KK, Bell E, Patel RK, Jardine AG, Morris STW, Schneider MP, Delles C, and Mark PB
- Abstract
Background: Premature cardiovascular disease in patients with chronic kidney disease (CKD) is not explained by traditional risk factors and oxidative stress may contribute via endothelial and vascular dysfunction. We investigated the effect of ascorbic acid on oxidative stress and vascular function in CKD patients compared with controls with hypertension (HTN)., Methods: A crossover study of intravenous saline and ascorbic acid was conducted. Biomarkers of oxidative stress were measured, while pulse wave analysis and brachial flow - mediated dilatation were performed to assess large artery and endothelial function., Results: Twenty HTN and 30 CKD patients Stages 3-5 were recruited. Serum ascorbic acid was significantly lower in patients with CKD. In both groups, ascorbic acid significantly increased total antioxidant potential and superoxide. Asymmetric dimethylarginine (ADMA) was reduced significantly by ascorbic acid in the CKD group and on multivariate regression analysis, age and the presence of CKD were predictors of ADMA response to ascorbic acid. Although no effect on FMD was observed, central blood pressure and augmentation index were reduced significantly in both groups., Conclusions: Ascorbic acid has pro- and antioxidant effects, reducing central blood pressure and augmentation index in HTN and CKD. Ascorbic acid reduces serum ADMA in CKD, which may have longer-term benefits.
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- 2018
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4. Deleterious effects of phosphate on vascular and endothelial function via disruption to the nitric oxide pathway.
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Stevens KK, Denby L, Patel RK, Mark PB, Kettlewell S, Smith GL, Clancy MJ, Delles C, and Jardine AG
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- Animals, Cardiovascular Diseases blood, Cardiovascular Diseases pathology, Cells, Cultured, Cross-Over Studies, Cyclic GMP metabolism, Endothelial Cells enzymology, Endothelium, Vascular metabolism, Fibroblast Growth Factor-23, Fibroblast Growth Factors blood, Humans, Hyperphosphatemia blood, Hyperphosphatemia pathology, Male, Nitric Oxide Synthase Type III metabolism, Phosphates physiology, Phosphates toxicity, Rats, Rats, Inbred WKY, Renal Insufficiency, Chronic blood, Renal Insufficiency, Chronic pathology, Risk Factors, Signal Transduction, Single-Blind Method, Vasodilation drug effects, Cardiovascular Diseases etiology, Hyperphosphatemia complications, Nitric Oxide physiology, Renal Insufficiency, Chronic complications
- Abstract
Background: Hyperphosphataemia is an independent risk factor for accelerated cardiovascular disease in chronic kidney disease (CKD), although the mechanism for this is poorly understood. We investigated the effects of sustained exposure to a high-phosphate environment on endothelial function in cellular and preclinical models, as well as in human subjects., Methods: Resistance vessels from rats and humans (± CKD) were incubated in a normal (1.18 mM) or high (2.5 mM) phosphate concentration solution and cells were cultured in normal- (0.5 mM) or high-phosphate (3 mM) concentration media. A single-blind crossover study was performed in healthy volunteers, receiving phosphate supplements or a phosphate binder (lanthanum), and endothelial function measured was by flow-mediated dilatation., Results: Endothelium-dependent vasodilatation was impaired when resistance vessels were exposed to high phosphate; this could be reversed in the presence of a phosphodiesterase-5-inhibitor. Vessels from patients with CKD relaxed normally when incubated in normal-phosphate conditions, suggesting that the detrimental effects of phosphate may be reversible. Exposure to high-phosphate disrupted the whole nitric oxide pathway with reduced nitric oxide and cyclic guanosine monophosphate production and total and phospho endothelial nitric oxide synthase expression. In humans, endothelial function was reduced by chronic phosphate loading independent of serum phosphate, but was associated with higher urinary phosphate excretion and serum fibroblast growth factor 23., Conclusions: These directly detrimental effects of phosphate, independent of other factors in the uraemic environment, may explain the increased cardiovascular risk associated with phosphate in CKD., (© The Author 2016. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)
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- 2017
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5. Renal association clinical practice guideline in post-operative care in the kidney transplant recipient.
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Baker RJ, Mark PB, Patel RK, Stevens KK, and Palmer N
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- Graft Rejection diagnosis, Graft Rejection prevention & control, Humans, Kidney Failure, Chronic surgery, Postoperative Care methods, Immunosuppressive Agents therapeutic use, Kidney Transplantation standards, Postoperative Care standards, Practice Guidelines as Topic standards
- Abstract
These guidelines cover the care of patients from the period following kidney transplantation until the transplant is no longer working or the patient dies. During the early phase prevention of acute rejection and infection are the priority. After around 3-6 months, the priorities change to preservation of transplant function and avoiding the long-term complications of immunosuppressive medication (the medication used to suppress the immune system to prevent rejection). The topics discussed include organization of outpatient follow up, immunosuppressive medication, treatment of acute and chronic rejection, and prevention of complications. The potential complications discussed include heart disease, infection, cancer, bone disease and blood disorders. There is also a section on contraception and reproductive issues.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and AD depending on the quality of the evidence that the recommendation is based on.
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- 2017
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6. High Intrapatient Tacrolimus Variability Is Associated With Worse Outcomes in Renal Transplantation Using a Low-Dose Tacrolimus Immunosuppressive Regime.
- Author
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Whalen HR, Glen JA, Harkins V, Stevens KK, Jardine AG, Geddes CC, and Clancy MJ
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- Acute Disease, Adult, Aged, Calcineurin Inhibitors adverse effects, Calcineurin Inhibitors blood, Disease-Free Survival, Drug Monitoring, Drug Therapy, Combination, Electronic Health Records, Female, Glomerular Filtration Rate drug effects, Graft Rejection diagnosis, Graft Rejection immunology, Graft Rejection mortality, Graft Survival drug effects, Humans, Immunosuppressive Agents adverse effects, Immunosuppressive Agents blood, Kaplan-Meier Estimate, Kidney immunology, Kidney pathology, Kidney physiopathology, Kidney Diseases chemically induced, Kidney Transplantation mortality, Male, Middle Aged, Retrospective Studies, Risk Factors, Scotland, Tacrolimus adverse effects, Tacrolimus blood, Time Factors, Treatment Outcome, Calcineurin Inhibitors administration & dosage, Graft Rejection prevention & control, Immunosuppressive Agents administration & dosage, Kidney drug effects, Kidney Transplantation adverse effects, Tacrolimus administration & dosage
- Abstract
Background: High intrapatient tacrolimus variability has been associated with worse clinical outcomes postrenal transplantation. Theoretically, tacrolimus levels consistently outside the target therapeutic window may result in allograft dysfunction as subtherapeutic tacrolimus levels predispose to episodes of acute rejection, whereas supratherapeutic levels may cause nephrotoxicity., Methods: We investigated the effect of tacrolimus variability in a "Symphony" style low-dose tacrolimus based regime, by collecting data from 432 patients over a 4-year period.Three hundred seventy-six patients were included, with a mean follow-up of 1495 days. Tacrolimus variability 6 to 12 months after renal transplantation was calculated, and outcomes were compared in low (n = 186) and high variability (n = 190) groups., Results: High variability patients were found to be at increased risk of rejection during the first posttransplant year (P = 0.0054) and to have reduced rejection-free survival (hazard ratio, 1.953; 95% confidence interval, 1.234-3.093; P = 0.0054). High variability patients had significantly worse (P < 0.0001) glomerular filtration rates at 1, 2, 3, and 4 years posttransplant. High variability patients were at increased risk of allograft loss (hazard ratio, 4.928; 95% confidence interval, 2.050-11.85; P = 0.0004)., Conclusions: This suggests that highly variable tacrolimus levels predict worse outcomes postrenal transplantation, although the causal nature of this relationship remains unclear. High tacrolimus variability may identify a subset of patients who warrant increased surveillance and patient education regarding dietary and medication compliance.
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- 2017
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7. Risk factors and outcome of stroke in renal transplant recipients.
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Findlay MD, Thomson PC, MacIsaac R, Jardine AG, Patel RK, Stevens KK, Rutherford E, Clancy M, Geddes CC, Dawson J, and Mark PB
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- Adult, Female, Humans, Incidence, Male, Middle Aged, Retrospective Studies, Risk Factors, Stroke etiology, Survival Rate trends, United Kingdom epidemiology, Kidney Failure, Chronic surgery, Kidney Transplantation adverse effects, Postoperative Complications, Risk Assessment, Stroke epidemiology, Transplant Recipients statistics & numerical data
- Abstract
Stroke incidence is high in end-stage renal disease, and risk factors differ between the dialysis and general populations. However, risk factors and outcomes following renal transplantation remain unclear. We analyzed all adult patients with a functioning renal transplant from 01/01/2007 to 12/31/2012. Data were extracted from the electronic patient record. Variables associated with stroke were identified by survival analyses; demographic, clinical, and imaging and laboratory variables were assessed and case fatality determined. Follow-up was until 05/12/2013. A total of 956 patients were identified (median age 40.1 years, 59.9% male). Atrial fibrillation (AF) prevalence was 9.2%, and 38.2% received a transplant during follow-up. A total of 26 (2.7%) experienced a stroke during 4409 patient-years of follow-up (84.6% ischemic). Stroke incidence was 5.96/1000 patient-years. Factors associated with stroke on regression analysis were prior stroke, diabetes, age, systolic hypertension, and hemoglobin. Atrial fibrillation was associated with time to stroke (P<0.001). Warfarin did not associate with ischemic stroke risk in those with AF. Fatality was 19.2% at 7, 23.1% at 28, and 42.3% at 365 days after stroke. Patients with a functioning renal transplant have a high stroke incidence and case fatality. Unlike those on hemodialysis, risk factors are similar to the general population. We did not demonstrate benefit from warfarin use in those with AF., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2016
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8. Non-Contrast Renal Magnetic Resonance Imaging to Assess Perfusion and Corticomedullary Differentiation in Health and Chronic Kidney Disease.
- Author
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Gillis KA, McComb C, Patel RK, Stevens KK, Schneider MP, Radjenovic A, Morris ST, Roditi GH, Delles C, and Mark PB
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- Adult, Aged, Case-Control Studies, Female, Humans, Kidney Cortex physiology, Kidney Cortex physiopathology, Kidney Medulla physiology, Kidney Medulla physiopathology, Male, Middle Aged, Young Adult, Kidney Cortex diagnostic imaging, Kidney Failure, Chronic diagnostic imaging, Kidney Medulla diagnostic imaging, Magnetic Resonance Imaging methods
- Abstract
Aims: Arterial spin labelling (ASL) MRI measures perfusion without administration of contrast agent. While ASL has been validated in animals and healthy volunteers (HVs), application to chronic kidney disease (CKD) has been limited. We investigated the utility of ASL MRI in patients with CKD., Methods: We studied renal perfusion in 24 HVs and 17 patients with CKD (age 22-77 years, 40% male) using ASL MRI at 3.0T. Kidney function was determined using estimated glomerular filtration rate (eGFR). T1 relaxation time was measured using modified look-locker inversion and xFB02;ow-sensitive alternating inversion recovery true-fast imaging and steady precession was performed to measure cortical and whole kidney perfusion., Results: T1 was higher in CKD within cortex and whole kidney, and there was association between T1 time and eGFR. No association was seen between kidney size and volume and either T1, or ASL perfusion. Perfusion was lower in CKD in cortex (136 ± 37 vs. 279 ± 69 ml/min/100 g; p < 0.001) and whole kidney (146 ± 24 vs. 221 ± 38 ml/min/100 g; p < 0.001). There was significant, negative, association between T1 longitudinal relaxation time and ASL perfusion in both the cortex (r = -0.75, p < 0.001) and whole kidney (r = -0.50, p < 0.001). There was correlation between eGFR and both cortical (r = 0.73, p < 0.01) and whole kidney (r = 0.69, p < 0.01) perfusion., Conclusions: Significant differences in renal structure and function were demonstrated using ASL MRI. T1 may be representative of structural changes associated with CKD; however, further investigation is required into the pathological correlates of reduced ASL perfusion and increased T1 time in CKD., (© 2016 S. Karger AG, Basel.)
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- 2016
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9. Serum phosphate and social deprivation independently predict all-cause mortality in chronic kidney disease.
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Solbu MD, Thomson PC, Macpherson S, Findlay MD, Stevens KK, Patel RK, Padmanabhan S, Jardine AG, and Mark PB
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- Aged, Biomarkers blood, Cohort Studies, Comorbidity, Female, Humans, Hyperphosphatemia psychology, Incidence, Male, Middle Aged, Renal Insufficiency, Chronic blood, Reproducibility of Results, Risk Assessment methods, Scotland epidemiology, Sensitivity and Specificity, Survival Analysis, Hyperphosphatemia diagnosis, Hyperphosphatemia mortality, Phosphates blood, Renal Insufficiency, Chronic mortality, Renal Insufficiency, Chronic psychology, Social Isolation psychology
- Abstract
Background: Hyperphosphataemia is linked to cardiovascular disease and mortality in chronic kidney disease (CKD). Outcome in CKD is also affected by socioeconomic status. The objective of this study was to assess the associations between serum phosphate, multiple deprivation and outcome in CKD patients., Methods: All adult patients currently not on renal replacement therapy (RRT), with first time attendance to the renal outpatient clinics in the Glasgow area between July 2010 and June 2014, were included in this prospective study. Area socioeconomic status was assessed as quintiles of the Scottish Index of Multiple Deprivation (SIMD). Outcomes were all-cause and cardiovascular mortality and commencement of RRT., Results: The cohort included 2950 patients with a median (interquartile range) age 67.6 (53.6-76.9) years. Median (interquartile range) eGFR was 38.1 (26.3-63.5) ml/min/1.73 m(2), mean (± standard deviation) phosphate was 1.13 (± 0.24) mmol/L and 31.6 % belonged to the most deprived quintile (SIMD quintile I). During follow-up 375 patients died and 98 commenced RRT. Phosphate ≥ 1.50 mmol/L was associated with all-cause (hazard ratio (HR) 2.51; 95 % confidence interval (CI) 1.63-3.89) and cardiovascular (HR 5.05; 95 % CI 1.90-13.46) mortality when compared to phosphate 0.90-1.09 mmol/L in multivariable analyses. SIMD quintile I was independently associated with all-cause mortality. Phosphate did not weaken the association between deprivation index and mortality, and there was no interaction between phosphate and SIMD quintiles. Neither phosphate nor SIMD predicted commencement of RRT., Conclusions: Multiple deprivation and serum phosphate were strong, independent predictors of all-cause mortality in CKD and showed no interaction. Phosphate also predicted cardiovascular mortality. The results suggest that phosphate lowering should be pursued regardless of socioeconomic status.
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- 2015
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10. Association between serum phosphate and calcium, long-term blood pressure, and mortality in treated hypertensive adults.
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Patel RK, Jeemon P, Stevens KK, Mccallum L, Hastie CE, Schneider A, Jardine AG, Mark PB, and Padmanabhan S
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- Adult, Antihypertensive Agents therapeutic use, Female, Follow-Up Studies, Humans, Hypertension drug therapy, Hypertension epidemiology, Male, Blood Pressure physiology, Calcium blood, Hypertension blood, Hypertension mortality, Phosphates blood
- Abstract
Objectives: Abnormalities of bone mineral parameters are associated with cardiovascular morbidity and mortality in patients with chronic kidney disease and the general population., Methods: We assessed the impact of baseline serum phosphate and calcium on longitudinal blood pressure (BP) control and survival in hypertensive adults. We studied 9260 hypertensive adults followed for 40 years (151 789 person-years). Changes in BP over initial 5-year follow-up were analysed using generalized estimating equations. Survival analyses were performed using Cox proportional hazards model., Results: Serum phosphate levels were higher in hypertensive women (1.10 mmol/l ± 0.20) than compared to men (1.02 mmol/l ± 0.21). In treated hypertensive patients, higher baseline serum phosphate was significantly associated with poor longitudinal SBP reduction (one standard deviation increase in phosphate was associated with 0.22 and 0.59 mmHg higher SBP at 5 years in men and women, respectively). Higher serum phosphate was significantly associated with all-cause and cardiovascular mortality in men, whereas in men and women, serum calcium significantly predicted all-cause and noncardiovascular mortality. In hypertensive patients with chronic kidney disease, higher phosphate was significantly associated with poorer survival., Conclusion: In hypertensive patients, serum phosphate and calcium are significantly associated with reduced all-cause and cardiovascular survival and this appears not to be related to BP control.
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- 2015
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11. Risk Factors of Ischemic Stroke and Subsequent Outcome in Patients Receiving Hemodialysis.
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Findlay MD, Thomson PC, Fulton RL, Solbu MD, Jardine AG, Patel RK, Stevens KK, Geddes CC, Dawson J, and Mark PB
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- Aged, Aged, 80 and over, Brain Ischemia etiology, Brain Ischemia mortality, Comorbidity, Female, Follow-Up Studies, Humans, Incidence, Kidney Failure, Chronic therapy, Male, Middle Aged, Prevalence, Risk Factors, Scotland epidemiology, Stroke etiology, Stroke mortality, Brain Ischemia epidemiology, Kidney Failure, Chronic epidemiology, Renal Dialysis statistics & numerical data, Stroke epidemiology
- Abstract
Background and Purpose: End-stage renal disease (ESRD) requiring hemodialysis carries up to a 10-fold greater risk of stroke than normal renal function. Knowledge on risk factors and management strategies derived from the general population may not be applicable to those with ESRD. We studied a large ESRD population to identify risk factors and outcomes for stroke., Methods: All adult patients receiving hemodialysis for ESRD from January 1, 2007, to December 31, 2012, were extracted from the electronic patient record. Variables associated with stroke were identified by survival analysis; demographic, clinical, imaging, and dialysis-related variables were assessed, and case-fatality was determined. Follow-up was until December 31, 2013., Results: A total of 1382 patients were identified (mean age, 60.5 years; 58.5% men). The prevalence of atrial fibrillation was 21.2%, and 59.4% were incident hemodialysis patients. One hundred and sixty patients (11.6%) experienced a stroke during 3471 patient-years of follow-up (95% ischemic). Stroke incidence was 41.5/1000 patient-years in prevalent and 50.1/1000 patient-years in incident hemodialysis patients. Factors associated with stroke on regression analysis were prior stroke, diabetes mellitus, and age at starting renal replacement therapy. Atrial fibrillation was not significantly associated with stroke, and warfarin did not affect stroke risk in warfarin-treated patients. Fatality was 18.8% at 7 days, 26.9% at 28 days, and 56.3% at 365 days after stroke., Conclusions: Incidence of stroke is high in patients with ESRD on hemodialysis with high case-fatality. Incident hemodialysis patients had the highest stroke incidence. Many, but not all, important risk factors commonly associated with stroke in the general population were not associated with stroke in patients receiving hemodialysis., (© 2015 American Heart Association, Inc.)
- Published
- 2015
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12. Phosphate as a cardiovascular risk factor: effects on vascular and endothelial function.
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Stevens KK, Patel RK, Mark PB, Delles C, and Jardine AG
- Abstract
Background: Hyperphosphataemia is a risk factor for accelerated cardiovascular disease in chronic kidney disease. The mechanism is poorly understood; it is unclear whether phosphate has direct effects or effects mediated via calcification or FGF23. We investigated direct effects of phosphate on endothelial function using myography to study rat and human blood vessels. In addition we assessed the effects of phosphate loading on endothelial function in a clinical study., Methods: Resistance vessels from patients with (n=12) and without (n=13) chronic kidney disease were incubated in normal or high phosphate. Vasoconstrictor and vasorelaxation responses were measured. Concentration-response curves were constructed and comparisons made. Identical experiments were performed in rat mesenteric vessels with and without phosphodiesterase type 5 inhibitor. A cross-over study was done in 19 healthy volunteers receiving phosphate supplements or binders and endothelial function measured by flow mediated dilatation (FMD). Primary outcome was percent change in FMD from baseline., Findings: Nine to 13 vessels were used in each group. Endothelium-dependent vasodilatation was impaired in high compared with normal phosphate in rat (mean maximum vasodilatation 64% [SE 9] vs 95 [1], p<0·001) and human vessels with (25·3 [11·1] vs 75·7 [13·6], p<0·001) and without chronic kidney disease (42·9 [12] vs 79·4 [8·2], p=0·003). In rat vessels, these effects were reversed by a phosphodiesterase type 5 inhibitor. In vivo in volunteers, endothelial function was reduced by phosphate loading (median maximum vasodilatation 3·38% [IQR 2·57-5·26] vs 8·4 [6·2-11·6], p<0·001); this effect was independent of serum phosphate concentration but associated with urinary phosphate excretion and serum FGF23 concentrations., Interpretation: Prolonged exposure to phosphate is associated with endothelial dysfunction, a direct effect of phosphate, which might contribute to cardiovascular risk in chronic kidney disease. In a high phosphate environment, endothelial and vascular dysfunction is evident in blood vessels and in man exposed to prolonged oral phosphate loading. These effects might be mediated by disruption of the NO pathway., Funding: British Heart Foundation, Darlinda's Charity for Renal Research., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
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- 2015
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13. Effect of left atrial and ventricular abnormalities on renal transplant recipient outcome-a single-center study.
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Patel RK, Pennington C, Stevens KK, Taylor A, Gillis K, Rutherford E, Johnston N, Jardine AG, and Mark PB
- Abstract
Background: Premature cardiovascular (CV) death is the commonest cause of death in renal transplant recipients. Abnormalities of left ventricular (LV) structure (collectively termed uremic cardiomyopathy) and left atrial (LA) dilation, a marker of fluid status and diastolic function, are risk factors for reduced survival in patients with end stage renal disease (ESRD). In the present analysis, we studied the impact of pre-transplant LA and LV abnormalities on survival after successful renal transplantation (RT)., Methods: One hundred nineteen renal transplant recipients (first transplant, deceased donors) underwent cardiovascular MRI (CMR) as part of CV screening prior to inclusion on the waiting list. Data regarding transplant function and patient survival after transplantation were collected., Results: Median post-transplant follow-up was 4.3 years (interquartile range (IQR) 1.9, 6.2). During the post-transplant period, 13 patients returned to dialysis after graft failure and 23 patients died with a functioning graft. Survival analyses, censoring for patients returning to dialysis, showed that pre-transplant LV hypertrophy and elevated LA volume were significantly associated with reduced survival after transplantation. Multivariate Cox regression analyses demonstrated that longer waiting time, poorer transplant function, presence of LV hypertrophy and higher LA volume on screening CMR and female sex were independent predictors of death in patients with a functioning transplant., Conclusions: Presence of LVH and higher LA volume are significant, independent predictors of death in patients who are wait-listed and proceed with renal transplantation.
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- 2014
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14. Dense breast notification: anatomy, imaging, and patient awareness.
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Jones TL and Stevens KK
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- Breast Neoplasms pathology, Female, Humans, United States, Absorptiometry, Photon standards, Breast Neoplasms diagnostic imaging, Disclosure legislation & jurisprudence, Informed Consent legislation & jurisprudence, Mammography standards, Patient Participation legislation & jurisprudence, Physician's Role
- Abstract
Purpose: To review the current literature pertaining to dense breast anatomy, imaging considerations, and patient notification laws., Methods: The literature for this review was obtained by searching for peer-reviewed articles about breast density and breast density notification for the years 2009 to 2012 using Google Scholar., Results: The research regarding dense breast anatomy, imaging options related to dense breasts, and notification laws yields important considerations for patients, physicians, and imaging science professionals performing the procedures., Discussion: Dense breast anatomy can hinder the accuracy of screening mammography. Breast density notification laws inform patients about the density level of their breasts and introduce them to additional imaging options. The laws raise questions about whether notification is necessary and beneficial or whether it leads to increased radiation exposure, health care costs, and stress to the patient., Conclusion: Dense breast notification laws serve to inform patients about their anatomy and provide them with the knowledge to make informed health care decisions.
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- 2014
15. Predictors of sustained arteriovenous access use for haemodialysis.
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Stoumpos S, Stevens KK, Aitken E, Kingsmore DB, Clancy MJ, Fox JG, and Geddes CC
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- Adolescent, Adult, Age Factors, Aged, Catheterization, Central Venous, Comorbidity, Diabetes Mellitus epidemiology, Disease Progression, Female, Glomerular Filtration Rate, Humans, Kidney Failure, Chronic epidemiology, Kidney Failure, Chronic metabolism, Male, Middle Aged, Myocardial Ischemia epidemiology, Peripheral Vascular Diseases epidemiology, Practice Guidelines as Topic, Proteinuria, Renal Insufficiency, Chronic epidemiology, Renal Insufficiency, Chronic metabolism, Renal Insufficiency, Chronic therapy, Retrospective Studies, Severity of Illness Index, Sex Factors, Time Factors, Young Adult, Arteriovenous Shunt, Surgical statistics & numerical data, Kidney Failure, Chronic therapy, Kidney Transplantation, Renal Dialysis methods
- Abstract
Background: Guidelines encourage early arteriovenous (AV) fistula (AVF) planning for haemodialysis (HD). The aim of this study was to estimate the likelihood of sustained AV access use taking into account age, sex, comorbidity, anatomical site of first AVF and, for pre-dialysis patients, eGFR and proteinuria., Methods: 1,092 patients attending our centre who had AVF as their first AV access procedure between January 1, 2000 and August 23, 2012 were identified from the electronic patient record. The primary end-point was time to first sustained AV access use, defined as use of any AV access for a minimum of 30 consecutive HD sessions., Results: 52.9% (n = 578) of the patients ultimately achieved sustained AV access use. The main reasons for AV access non-use were AVF failure to mature and death. The 3-year Kaplan-Meier probability of sustained AV access use was 68.8% for those not on renal replacement therapy (RRT) (n = 688) and 74.2% for those already on RRT (n = 404) at the time of first AVF. By multivariate analysis in patients not on RRT, male sex (HR 2.22; p < 0.001), uPCR (HR 1.03; p = 0.03) and eGFR (hazard ratio, HR 0.85; p < 0.001) were independent predictors of AV access use. In patients already on RRT, age (HR 0.98; p < 0.001) and peripheral vascular disease (HR 0.48; p = 0.02) were independent predictors of AV access use., Conclusion: Our data suggest that refinement of the current guideline for timing of AV access creation in planning RRT is justified to take into account individual factors that contribute to the likelihood of technical success and clinical need.
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- 2014
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16. Proteinuria and outcome after renal transplantation: ratios or fractions?
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Stevens KK, Patel RK, Methven S, Clancy MJ, Fox JG, Jardine AG, and Geddes CC
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- Adult, Creatinine blood, Creatinine urine, Female, Follow-Up Studies, Humans, Kaplan-Meier Estimate, Kidney physiopathology, Kidney Transplantation adverse effects, Male, Middle Aged, Multivariate Analysis, Predictive Value of Tests, Proportional Hazards Models, ROC Curve, Risk Factors, Kidney Transplantation mortality, Postoperative Complications mortality, Postoperative Complications physiopathology, Proteinuria mortality, Proteinuria physiopathology
- Abstract
Background: Proteinuria is associated with poorer outcomes in renal transplant recipients. Fractional excretion of total protein (FEPR) may better reflect kidney damage than urine protein-to-creatinine ratio (PCR)., Methods: We assessed FEPR (FEPR = [serum creatinine × urine protein] / [serum protein × urine creatinine], %) and PCR ([urinary protein/urinary creatinine] × 1000, mg/mM) 1 year after first renal transplantation as predictors of transplant failure. The primary endpoints were transplant failure and death. The use of the tests was analyzed by constructing receiver operator characteristic curves and comparing the area under the curve. Using receiver operator characteristic analysis, patients were stratified into high- and low-risk groups., Results: Two hundred nineteen recipients were followed up for a median of 4.9 years. At a median of 2.7 years, 11.4% (n=25) of the transplants failed. Eight percent (n=17) of the patients died. The area under the curve was higher for FEPR than PCR (0.92 vs. 0.84). Patients with an FEPR of 0.019% or higher had a 3.4-fold (P=0.003) increased risk of transplant failure and a 2.3-fold (P=0.02) increased risk of death compared with those with an FEPR of less than 0.019%. Patients with a PCR of 97 mg/mM or greater had a 2.1-fold (P=0.04) increased risk of transplant failure and a 1.6-fold (P=0.04) increased risk of death compared with those with a PCR of less than 97 mg/mM (P=0.04). In multivariate analysis with time to transplant failure as the dependent variable, FEPR and PCR were independent predictors of transplant failure (hazards ratio, 1.07 [P=0.013] and 1.03 [P=0.03], respectively)., Conclusions: FEPR and PCR at 1 year are independent predictors of transplant failure, but FEPR may be superior.
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- 2013
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17. Sleep apnoea and the potential benefits of a good night's sleep in patients receiving maintenance dialysis.
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Patel RK, Stevens KK, and Jardine AG
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- Female, Humans, Male, Body Fluids physiology, Kidney Failure, Chronic complications, Pharynx physiopathology, Renal Dialysis adverse effects, Sleep Apnea, Obstructive etiology, Water chemistry
- Published
- 2013
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18. Altered relative concentrations of high-energy phosphates in patients with uraemic cardiomyopathy measured by magnetic resonance spectroscopy.
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Patel RK, Mark PB, Macnaught G, Stevens KK, McQuarrie EP, Steedman T, Gillis K, Dargie HJ, and Jardine AG
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- Case-Control Studies, Female, Follow-Up Studies, Humans, Hypertension complications, Hypertrophy, Left Ventricular diagnosis, Hypertrophy, Left Ventricular etiology, Male, Middle Aged, Phosphorus Isotopes metabolism, Prognosis, Cardiomyopathies diagnosis, Cardiomyopathies etiology, Kidney Failure, Chronic complications, Magnetic Resonance Spectroscopy, Phosphates analysis, Uremia complications
- Abstract
Background: Premature sudden cardiovascular death is the commonest cause of death in end-stage renal disease (ESRD) patients and is associated with uraemic cardiomyopathy [left ventricular hypertrophy (LVH), systolic dysfunction (LVSD) or LV dilation]. High-energy phosphates (HEP), quantified using phosphorus-31 magnetic resonance spectroscopy, are reduced in patients with diabetes, heart failure and uraemia. Phosphocreatine:β adenosine triphosphate (PCr:ATP) ratio is an index of metabolic activity. We compared resting HEPs in ESRD patients and hypertensive patients (with and without LVH) who had normal renal function (LVH-only or normal myocardia). We also assessed associations of HEP levels with abnormalities of uraemic cardiomyopathy., Methods: Fifty-three ESRD and 30 hypertensive patients (18 with LVH, 12 with normal myocardia) underwent phosphorus magnetic resonance spectroscopy of their left ventricle. PCr:ATP ratios were calculated from (31)P-MR spectra obtained from long-axis views of the left ventricle., Results: There were no significant differences in age, LV mass, chamber sizes and ejection fraction between patient groups. PCr:ATP was significantly lower in ESRD patients compared to hypertensive patients, irrespective of the presence or absence of LVH (P = 0.01). In the ESRD group, PCr:ATP was significantly lower in patients with LVSD (P = 0.05) and LV dilation (P = 0.01). LVH was not associated with significant difference in PCr:ATP., Conclusions: ESRD patients have lower HEP levels compared to hypertensive patients. Lower PCr:ATP ratio, indicating altered myocardial metabolic function in ESRD patients, is associated with features of uraemic cardiomyopathy.
- Published
- 2012
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19. How to identify and manage diabetes mellitus after renal transplantation.
- Author
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Stevens KK, Patel RK, and Jardine AG
- Subjects
- Glucose Intolerance diagnosis, Glucose Intolerance etiology, Glucose Intolerance therapy, Graft Survival, Humans, Postoperative Complications therapy, Risk Factors, Diabetes Mellitus diagnosis, Diabetes Mellitus etiology, Diabetes Mellitus therapy, Immunosuppressive Agents adverse effects, Kidney Transplantation, Postoperative Complications diagnosis
- Abstract
New-onset diabetes after transplantation (NODAT) has serious consequences for the patient in terms of overall survival, graft function and graft survival. The incidence of NODAT and impaired glucose tolerance has probably been underestimated previously because of lack of a universal diagnostic definition. Many risk factors have been identified, a proportion of which are modifiable. Early identification of those who are at high risk of NODAT and strategies to reduce risk will help to reduce the morbidity and mortality resulting from this condition. Where prevention is not possible, stringent management strategies are essential. Although, this article focuses on NODAT in the renal transplant recipient and considers the scale of the problem, impact on patient and transplant survival, determinants and risk factors for, and the management of, impaired glucose tolerance and NODAT, much of it will also be applicable to other types of solid organ transplantation., (© 2012 European Dialysis and Transplant Nurses Association/European Renal Care Association.)
- Published
- 2012
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20. Deceased donor transplantation in the elderly--are we creating false hope?
- Author
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Stevens KK, Woo YM, Clancy M, McClure JD, Fox JG, and Geddes CC
- Subjects
- Adolescent, Adult, Aged, Cadaver, Delayed Graft Function, Female, Follow-Up Studies, Glomerular Filtration Rate, Graft Survival, Humans, Kidney Failure, Chronic mortality, Kidney Function Tests, Male, Middle Aged, Outcome Assessment, Health Care, Prognosis, Prospective Studies, Risk Factors, Survival Rate, Tissue and Organ Procurement, Young Adult, Aging, Graft Rejection diagnosis, Kidney Failure, Chronic therapy, Kidney Transplantation, Postoperative Complications
- Abstract
Background: Increasing numbers of older patients are developing established renal failure and considering kidney transplant as a renal replacement therapy (RRT) option. The probability of older patients actually receiving a deceased donor kidney transplant is unclear, preventing informed choice about pursuing the option of transplantation. We sought to analyse our RRT population to determine the probability of receiving a deceased donor kidney transplant in patients commencing RRT categorized by age and for whom there was no suitable living kidney donor., Methods: Patients commencing dialysis in our centre between 1992 and 2009 were identified. Time to listing on the deceased donor transplant waiting list and time to first deceased donor transplant were determined by Kaplan-Meier analysis for patients, categorized by age, with censoring at the date of first living donor kidney transplant, death or last dialysis., Results: One-thousand-five-hundred-and-thirteen patients were categorized into groups by age in years [1: <35 (n = 134), 2: 35-49.9 (n = 207), 3: 50-64.9 (n = 415), 4: >65-74.9 (n = 438) and 5: ≥ 75 (n = 319)]. The probability of being listed for deceased donor transplant within 1 year of commencing RRT was 75, 54, 27, 4 and 0.8% in Groups 1-5, respectively. If listed, the probability of receiving a deceased donor transplant within 5 years of starting RRT was 81, 48, 26, 8 and 0% in Groups 1-5, respectively. In Groups 1-4, 93% (n = 63), 87% (n = 65), 76% (n = 45) and 100% (n = 7) of the patients, respectively, who received a deceased donor transplant were alive and off dialysis 1 year after transplant. The reason patients who were listed did not receive a transplant was usually death on the waiting list., Conclusions: The likelihood of being listed for transplant falls with increasing age at the time of starting RRT. Even for patients listed for transplant, the probability of older patients actually receiving a transplant is much lower than for younger patients, with only 8% of listed patients aged 65-74.9 years being transplanted within 5 years. This is partly the result of death on the waiting list but may also be related to organ allocation policies. Assessment for possible deceased donor transplantation involves a considerable investment in time and effort for the patient, as well as in health care resources, and a patient's decision whether to proceed with assessment should be informed by the kind of information we have produced. As there may be regional and national variations in practice, each centre should generate such data for use locally.
- Published
- 2011
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21. SHARP: a stab in the right direction in chronic kidney disease.
- Author
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Stevens KK and Jardine AG
- Subjects
- Azetidines therapeutic use, Cardiovascular Diseases etiology, Cardiovascular Diseases mortality, Drug Therapy, Combination, Ezetimibe, Female, Humans, Male, Prognosis, Renal Dialysis adverse effects, Renal Dialysis methods, Renal Insufficiency, Chronic complications, Renal Insufficiency, Chronic mortality, Renal Insufficiency, Chronic therapy, Simvastatin therapeutic use, Treatment Outcome, Anticholesteremic Agents administration & dosage, Cardiovascular Diseases prevention & control, Renal Insufficiency, Chronic drug therapy
- Published
- 2011
- Full Text
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22. Serum phosphate and outcome at one year after deceased donor renal transplantation.
- Author
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Stevens KK, Morgan IR, Patel RK, Geddes CC, Mark PB, Jardine AG, and Delles C
- Subjects
- Cadaver, Female, Humans, Male, Middle Aged, Risk Factors, Survival Rate, Time Factors, Tissue Donors, Treatment Outcome, Kidney Transplantation mortality, Phosphates blood
- Abstract
Traditional risk factors do not adequately explain the increased prevalence of cardiovascular disease in renal patients. This study considered a "non-traditional" risk factor, serum phosphate and outcome in renal transplant recipients. Data from 377 patients who received a first deceased donor renal transplant between January 1, 1999, and December 31, 2008, were recorded; 10% (n=38) had diabetes, 16.7% (n=63) were smokers, and 18.8% (n=71) had a history of vascular disease. Three hundred and thirty-three patients were alive at the time of the analysis. Survivors were significantly younger, less likely to be smokers or diabetic, and had a higher estimated glomerular filtration rate at one yr post-transplantation. Serum phosphate was significantly lower in these patients (0.95 ± 0.23 vs. 1.04 ± 0.26, p = 0.031). Analysis of recipient survival, stratified by serum phosphate at one yr post-transplant, revealed that serum phosphate > 1.11 mMol/L was a significant predictor of all-cause mortality (p=0.006). Serum phosphate between 0.9 and 1.11 mMol/L afforded the best outcome. In multivariate analysis, serum phosphate remained a significant predictor of mortality (p=0.016). Serum phosphate at one yr after transplant seems to have a J-shaped relationship with mortality, and this effect is independent of traditional cardiovascular risk factors., (© 2011 John Wiley & Sons A/S.)
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- 2011
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23. Fibroblast growth factor 23 predicts left ventricular mass and induces cell adhesion molecule formation.
- Author
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Stevens KK, McQuarrie EP, Sands W, Hillyard DZ, Patel RK, Mark PB, and Jardine AG
- Abstract
Elevated FGF-23 is a predictor of mortality and is associated with LVH in CKD. It may be a biomarker or a direct toxin. We assessed the relationship between FGF-23 and LVH in CKD using CMRI. In vitro we studied the effect of phosphate, FGF-23, and Klotho on E-selectin and VCAM production in HUVECs. FGF-23 concentration correlates negatively with eGFR and positively with LVMI. FGF-23 was an independent predictor of LVH in CKD. E-selectin and VCAM production was elevated in HUVECs cultured in high phosphate with FGF-23 or Klotho. This effect was attenuated in cells exposed to both FGF-23 and Klotho. FGF-23 is an independent predictor of LVH as measured by CMRI. We show preliminary data which supports that FGF-23 is toxic resulting in activation of the vascular endothelium. We do not prove causality with elevated FGF-23 and LVH. Further research should ascertain if lowering levels of FGF-23 translates to improved clinical outcomes.
- Published
- 2011
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24. Association of left atrial volume with mortality among ESRD patients with left ventricular hypertrophy referred for kidney transplantation.
- Author
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Patel RK, Jardine AG, Mark PB, Cunningham AF, Steedman T, Powell JR, McQuarrie EP, Stevens KK, Dargie HJ, and Jardine AG
- Subjects
- Adult, Cardiovascular Diseases epidemiology, Female, Follow-Up Studies, Humans, Kaplan-Meier Estimate, Magnetic Resonance Imaging, Male, Middle Aged, Multivariate Analysis, Organ Size, Predictive Value of Tests, Prospective Studies, Retrospective Studies, Risk Factors, Ventricular Dysfunction, Left physiopathology, Heart Atria pathology, Hypertrophy, Left Ventricular physiopathology, Kidney Failure, Chronic mortality, Kidney Failure, Chronic surgery, Kidney Transplantation
- Abstract
Background: Left ventricular hypertrophy (LVH) is common in patients with end-stage renal disease (ESRD) and an independent risk factor for premature cardiovascular death. Left atrial volume (LAV), measured using echocardiography, predicts death in patients with ESRD. Cardiovascular magnetic resonance (CMR) imaging is a volume-independent method of accurately assessing cardiac structure and function in patients with ESRD., Study Design: Single-center prospective observational study to assess the determinants of all-cause mortality, particularly LAV, in a cohort of ESRD patients with LVH, defined using CMR imaging., Setting & Participants: 201 consecutive ESRD patients with LVH (72.1% men; mean age, 51.6 +/- 11.7 years) who had undergone pretransplant cardiovascular assessment were identified using CMR imaging between 2002-2008. LVH was defined as left ventricular mass index >84.1 g/m(2) (men) or >74.6 g/m(2) (women) based on published normal left ventricle dimensions for CMR imaging. Maximal LAV was calculated using the biplane area-length method at the end of left ventricle systole and corrected for body surface area., Predictors: CMR abnormalities, including LAV., Outcome: All-cause mortality., Results: 54 patients died (11 after transplant) during a median follow-up of 3.62 years. Median LAV was 30.4 mL/m(2) (interquartile range, 26.2-58.1). Patients were grouped into high (median or higher) or low (less than median) LAV. There were no significant differences in heart rate and mitral valve Doppler early to late atrial peak velocity ratio. Increased LAV was associated with higher mortality. Kaplan-Meier survival analysis showed poorer survival in patients with higher LAV (log rank P = 0.01). High LAV and left ventricular systolic dysfunction conferred similar risk and were independent predictors of death using multivariate analysis., Limitations: Only patients undergoing pretransplant cardiac assessment are included. Limited assessment of left ventricular diastolic function., Conclusions: Higher LAV and left ventricular systolic dysfunction are independent predictors of death in ESRD patients with LVH., (Copyright 2010 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
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25. Angiotensin blockade is associated with early graft dysfunction after live donor renal transplantation.
- Author
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Stevens KK, Patel RK, Clancy M, and Jardine AG
- Subjects
- Adolescent, Adult, Aged, Biomarkers blood, Creatinine blood, Delayed Graft Function metabolism, Delayed Graft Function therapy, Female, Humans, Male, Middle Aged, Pilot Projects, Renal Dialysis, Risk Factors, Time Factors, Treatment Outcome, Young Adult, Angiotensin II Type 1 Receptor Blockers adverse effects, Angiotensin-Converting Enzyme Inhibitors adverse effects, Delayed Graft Function etiology, Kidney Transplantation adverse effects, Living Donors, Renin-Angiotensin System drug effects
- Abstract
Background: Activation of the renin angiotensin system may contribute to the development of delayed graft function after renal transplantation. We, therefore, examined the impact of pretransplant treatment with blockers of the renin angiotensin system on early graft function after renal transplantation., Method: The case records of all patients who received a live donor transplant between January 2001 and August 2008 were reviewed., Results: Serum creatinine measurements were recorded for the first nine posttransplant days, in 94 recipients of live donor kidneys, where there were neither surgical nor hemodynamic complications and no documented rejection or infection. Forty patients (43%) were treated with a blocker of the renin-angiotensin-aldosterone system before transplantation. Serum creatinine levels fell more slowly in these patients (P=0.02). Two patients required hemodialysis after transplantation; both were on an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker., Conclusion: Live donor renal transplant recipients who are taking a renin-angiotensin-aldosterone system blocker at the time of transplantation are more likely to have impaired graft function postoperatively in the absence of other explanations. This observation requires further exploration in live and deceased donor renal transplantation.
- Published
- 2010
- Full Text
- View/download PDF
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