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(1) To provide commentary on the 2017 update to the Kidney Disease Improving Global Outcomes (KDIGO) 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD); (2) to apply the evidence-based guideline update for implementation within the Canadian health care system; (3) to provide comment on the care of children with chronic kidney disease (CKD); and (4) to identify research priorities for Canadian patients.The KDIGO 2017 Clinical Practice Guideline Update for the Diagnosis, Evaluation, Prevention, and Treatment of CKD-MBD.The commentary committee co-chairs selected potential members based on their knowledge of the Canadian kidney community, aiming for wide representation from relevant disciplines, academic and community centers, and different geographical regions.We agreed with many of the recommendations in the clinical practice guideline on the diagnosis, evaluation, prevention, and treatment of CKD-MBD. However, based on the uncommon occurrence of abnormalities in calcium and phosphate and the low likelihood of severe abnormalities in parathyroid hormone (PTH), we recommend against screening and monitoring levels of calcium, phosphate, PTH, and alkaline phosphatase in adults with CKD G3. We suggest and recommend monitoring these parameters in adults with CKD G4 and G5, respectively. In children, we agree that monitoring for CKD-MBD should begin in CKD G2, but we suggest measuring ionized calcium, rather than total calcium or calcium adjusted for albumin. With regard to vitamin D, we suggest against routine screening for vitamin D deficiency in adults with CKD G3-G5 and G1T-G5T and suggest following population health recommendations for adequate vitamin D intake. We recommend that the measurement and management of bone mineral density (BMD) be according to general population guidelines in CKD G3 and G3T, but we suggest against routine BMD testing in CKD G4-G5, CKD G4T-5T, and in children with CKD. Based on insufficient data, we also recommend against routine bone biopsy in clinical practice for adults with CKD or CKD-T, or in children with CKD, although we consider it an important research tool.The committee relied on the evidence summaries produced by KDIGO. The CSN committee did not replicate or update the systematic reviews.(1) Commenter les recommandations du KDIGO 2017 (Kidney Disease Improving Global Outcomes) sur les bonnes pratiques cliniques pour le diagnostic, l’évaluation et le traitement des troubles du métabolisme minéral osseux associés aux maladies rénales chroniques (TMO-MRC); (2) appliquer les lignes directrices actualisées et fondées sur les données probantes en vue de leur mise en œuvre dans le système de soins de santé canadien; (3) commenter les soins prodigués aux enfants atteints d’insuffisance rénale chronique (IRC) et (4) définir les priorités de recherche des patients Canadiens.Les recommandations du KDIGO 2017 (Kidney Disease Improving Global Outcomes) sur les bonnes pratiques cliniques pour le diagnostic, l’évaluation et le traitement des troubles du métabolisme minéral osseux associés aux maladies rénales chroniques (TMO-MRC).Les coprésidents du comité ont sélectionné les membres potentiels sur la base de leur connaissance du secteur de la santé rénale au Canada, tout en visant une bonne représentation de toutes les disciplines concernées, des centres universitaires et communautaires et des différentes régions géographiques.Nous approuvons un grand nombre des recommandations du KDIGO. Cependant, compte tenu de la rareté des anomalies du calcium et du phosphate et de la faible probabilité d’anomalies graves de la PTH (hormone parathyroïde), nous déconseillons le dépistage et la surveillance des taux de calcium, de phosphate, de PTH et de phosphatase alcaline chez les adultes atteints d’IRC de stade G3. Nous suggérons de mesurer ces paramètres chez les adultes de stade G4 et nous le recommandons pour les patients de stade G5. Chez les enfants, nous appuyons la recommandation de commencer la surveillance des TMO-MRC dès le stade G2, mais nous suggérons de mesurer le calcium ionisé plutôt que les taux de calcium total ou de calcium corrigé en fonction de l’albumine. En ce qui concerne la vitamine D, nous déconseillons le dépistage de routine des carences chez les adultes atteints d’IRC de stade G3 à G5 et G1T à G5T; nous suggérons plutôt de suivre les recommandations visant la population générale pour un apport adéquat en vitamine D. Nous recommandons que la mesure et la prise en charge de la densité minérale osseuse (DMO) se fassent en suivant les recommandations pour la population générale chez les adultes atteints d’IRC de stade G3 et G3T, mais nous déconseillons les tests de DMO de routine chez les adultes de stades G4-G5 et G4T-G5T, de même que chez les enfants atteints d’IRC. En raison de données insuffisantes, nous déconseillons également la pratique systématique d’une biopsie osseuse chez les adultes atteints d’IRC ou d’IRC-TMO, ainsi que chez les enfants atteints d’IRC, bien que nous la considérions comme un important outil de recherche.Le comité s’est appuyé sur le résumé des preuves rédigé par le KDIGO. Le comité de la SCN n’a pas reproduit ou mis à jour les revues systématiques.

Background Peritoneal dialysis (PD) for long-term management of diuretic resistant volume overload in heart failure (HF) may provide potential benefit with few adverse consequences. We examined the impact of PD on clinical status hospitalizations, and complications of therapy in severe end-stage HF. Methods A consecutive case series of 10 transplant ineligible patients receiving PD solely for HF volume management between 2007 and 2011 was evaluated with clinical data reviewed pre- and post-PD initiation. Results The mean ejection fraction (EF) pre-PD was 24.5 ± 6.0% with the majority of patients having NYHA class IIIB symptoms and moderate-severe right ventricular dysfunction. 9/10 patients were Stage 3 chronic kidney disease (CKD) or worse. After PD initiation, average weight loss was almost 7 kg (p = 0.016) with improvement in diuretic response, peripheral edema, and functional class. There was a significant decrease in re-hospitalization from an average of 3.2 ± 2.5 to 0.1 ± 0.3 admissions per patient (p = 0.007) and reduced average length of stay from 37 ± 36.7 to 0.78 ± 2.3 days (p = 0.019). Summary Objective criteriabased institution of PD for the treatment of diuretic refractory severe-end-stage HF was well tolerated and demonstrated favorable outcomes; these included improved clinical status, reduced hospitalizations and length of stay, with very few and easily treatable PDrelated complications. PD appears to be a viable option in refractory, end-stage congestive heart failure (CHF).

After heart surgery, acute kidney injury (AKI) confers substantial long-term risk of death and chronic kidney disease. We hypothesized that small changes in serum creatinine (SCr) levels measured within a few hours of exit from the operating room could help discriminate those at low versus high risk of AKI.Prospective cohort of 350 elective cardiac surgery patients (valve or coronary artery bypass grafting) recruited in Winnipeg, Canada. Baseline SCr level was obtained at the preoperative visit 2 weeks before surgery. The postoperative SCr level was drawn within 6 hours of completion of surgery and then daily while the patient was in the hospital.Immediate (ie,6 hours) postoperative SCr level change (ΔSCr), categorized as within 10% (reference), decrease10%, or increase10% relative to baseline.AKI, defined according to the new KDIGO (Kidney Disease: Improving Global Outcomes) consensus definition as an increase in SCr level0.3 mg/dL within 48 hours or1.5 times baseline within 1 week.We compared the C statistic of logistic models with and without inclusion of immediate postoperative ΔSCr.After surgery, 176 patients (52%) experienced a decrease10% in SCr level, 26 (7.4%) experienced an increase10%, and 143 had ΔSCr within ±10% of baseline. During hospitalization, 53 (14%) developed AKI. Bypass pump time, baseline estimated glomerular filtration rate, and European System for Cardiac Operative Risk Evaluation (euroSCORE) were associated with AKI in a parsimonious base logistic model. Added to the base model, immediate postoperative ΔSCr was associated strongly with subsequent AKI and significantly improved model discrimination over the base model (C statistic, 0.78 [95% CI, 0.71-0.85] vs 0.69 [95% CI, 0.62-0.77]; P0.001). A ≥10% SCr level decrease predicted significantly lower AKI risk (OR, 0.37; 95% CI, 0.18-0.76), whereas a ≥10% SCr level increase predicted significantly higher (OR, 6.38; 95% CI, 2.37-17.2) AKI risk compared with the reference category.We used a surrogate marker of AKI. External validation of our results is warranted.In elective cardiac surgery patients, measurement of immediate postoperative ΔSCr improves prediction of AKI.

Cardiovascular disease (CVD) is the leading cause of mortality in end-stage renal disease (ESRD), approximating a 10- to 20-fold higher risk of death in dialysis patients than in the general population. Despite this, dialysis patients often undergo fewer investigations, receive less invasive procedures, and are prescribed fewer medications compared with age-matched non-ESRD patients. A lack of randomized control trials for evidence-based treatment strategies in this population may explain some of these discrepancies, but there is concern that an attitude of "therapeutic nihilism" may be impacting on the medical care of these patients. In this review, we will explore CVD in the ESRD population. Specifically, we will try to address the following issues in patients with ESRD: (1) mechanisms of CVD, (2) cardiac evaluation and the role of coronary revascularization with percutaneous or coronary artery bypass procedures, and (3) cardiac pharmacotherapy use.

Background 2009 pandemic influenza A(H1N1) has led to a global increase in severe respiratory illness. Little is known about kidney outcomes and dialytic requirements in critically ill patients infected with pandemic H1N1. Study Design Prospective observational study. Setting & Participants 50 patients with pandemic H1N1 admitted to any of 7 intensive care units in Manitoba, Canada, were prospectively followed. Outcome & Measurements Outcomes were kidney injury and kidney failure defined using RIFLE (risk, injury, failure, loss, end-stage disease) criteria or need for dialysis therapy. Results The pandemic H1N1 group was composed of 50 critically ill patients with pandemic H1N1 with severe respiratory syndrome (47 confirmed cases, 3 probable). Kidney injury, kidney failure, and need for dialysis occurred in 66.7%, 66%, and 11% of patients, respectively. Mortality was 16%. Kidney failure was associated with increased death (OR, 11.29; 95% CI, 1.29-98.9), whereas the need for dialysis was associated with an increase in length of stay (RR, 2.38; 95% CI, 2.13-25.75). Limitations Small population studied from single Canadian province; thus, limited generalizability. Conclusions In critically ill patients with pandemic H1N1, kidney injury, kidney failure, and the need for dialysis are common and associated with an increase in mortality and length of intensive care unit stay.

Admission rates and outcomes of patients who have ESRD and are admitted to an intensive care unit (ICU) are not well defined. We conducted a historical cohort study using a prospective regional ICU database that captured all 11 adult ICUs in Winnipeg, Canada. Between 2000 and 2006, there were 34,965 total admissions to the ICU, 1173 (3.4%) of which were patients with ESRD. The main admission diagnoses among patients with ESRD were cardiac disease (31%), sepsis (15%), and arrest (10%). Compared with other patients in the ICU, those with ESRD were significantly younger but had more diabetes, peripheral arterial disease, and higher APACHE II (Acute Physiology and Chronic Health Evaluation II) scores; mean length of stay in the ICU was similar, however, between these two groups. Restricting the analysis to first admissions to the ICU, unadjusted in-hospital mortality was higher for patients with ESRD (16 versus 11%; P < 0.0001), but this difference did not persist after adjustment for baseline illness severity. In conclusion, although ESRD associates with increased mortality among patients who are admitted to the ICU, this effect is mostly a result of comorbidity.

New guidelines for the management of chronic kidney disease have been developed by the Canadian Society of Nephrology (Appendix 1 contains the full-text guidelines; available at [www.cmaj.ca/cgi/content/full/179/11/1154/DC1][1]). These guidelines describe key aspects of the management of chronic

cute kidney injury (AKI) is a serious andpotentially devastating complication inhospitalized patients. In the setting of cardiacsurgery with cardiopulmonary bypass (CPB),acute kidney failure requiring dialysis occurs inapproximately 1%-2% of patients and is associ-ated with a mortality in excess of 60%.

A young female with sickle cell disease was treated for biopsy-proven IgA nephropathy. Serum creatinine levels resolved to normal range, but a year later, she presented with oedema, hypertension and acute renal failure. A repeat renal biopsy showed acute-on-chronic thrombotic microangiopathy (TMA). We suggest that circulating microparticles could be a pathophysiological link between sickle cell disease and the development of renal TMA. This case emphasizes the importance of a further biopsy for acutely declining renal function, even when a definite diagnosis has been made from a previous biopsy.

Acute kidney injury (AKI) complicating cardiopulmonary bypass (CPB) results in increased morbidity and mortality. Urinary hepcidin-25 has been shown to be elevated in patients who do not develop AKI after CPB using semiquantitative mass spectrometry (SELDI TOF-MS). The goals of this study were to quantitatively validate these findings with ELISA and evaluate the diagnostic performance of hepcidin-25 for AKI.A nested, case-control analysis of urinary hepcidin-25 in AKI (n = 22) and non-AKI (n = 22) patients was conducted to validate the SELDI TOF-MS data at the following times: preoperatively; the start of CPB; 1 hour on CPB; on arrival to the intensive care unit; and postoperative days (POD) 1 and 3 to 5. The diagnostic performance of hepcidin-25 was then evaluated in the entire prospective observational cohort (n = 338) at POD 1. AKI was defined as Cr50% from baseline, within 72 hours postoperatively.Urinary hepcidin-25/Cr ratio was significantly elevated in all patients at POD 1 compared with baseline (P0.0005) and was also significantly elevated in non-AKI versus AKI patients at POD 1 (P0.0005). Increased log(10) hepcidin-25/Cr ratio was strongly associated with avoidance of AKI on univariate analysis. On multivariate analysis, the log(10) hepcidin-25/Cr ratio (P0.0001) was associated with avoidance of AKI with an area under the curve of 0.80, sensitivity 0.68, specificity 0.68, and negative predictive value 0.96.Elevated urinary hepcidin-25 on POD 1 is a strong predictor of avoidance of AKI beyond postoperative day 1.

End-stage renal disease (ESRD) patients admitted to the intensive care unit (ICU) have poor survival and high rates of readmission; however, little evidence exists on long-term outcomes. We set out to investigate the long-term (6 and 12 months) survival of ESRD patients admitted to the ICU and whether differential survival could be explained by dialysis modality and vascular access.We compared the admission characteristics, outcomes and readmission rates of 619 ESRD [95 peritoneal dialysis (PD), 334 hemodialysis with a catheter (HD CVC), 190 hemodialysis with an AV fistula (HD AVF)] patients admitted to 11 ICU's in Winnipeg, Manitoba, Canada. Parametric and nonparametric tests were used as appropriate to determine differences in baseline characteristics. Multivariable Cox and logistic regression was used to assess outcomes between the groups.The 6- and 12-month crude survival was 62 and 52%, respectively. In a univariate model, modality and vascular access were associated with an increased hazard ratio (HR) of death [PD HR 1.60 95% confidence interval (CI) 1.20-2.13, HD CVC HR 1.55 95% CI 1.25-1.93] compared to patients on HD with an AVF. In three different multivariate adjusted models, this association persisted with HRs for death of 1.63-1.75 for PD and 1.50-1.58 for HD CVC.Overall long-term survival of ESRD patients after admission to the ICU is poor. Being on PD or being dialyzed with a catheter was independently associated with an increased mortality.

Summary Background and objectives Elderly patients (>65 years old) are a rapidly growing demographic in the ESRD and intensive care unit (ICU) populations, yet the effect of ESRD status on critical illness in elderly patients remains unknown. Reliable estimates of prognosis would help to inform care and management of this frail and vulnerable population. Design, setting, participants, & measurements The effect of ESRD status on survival and readmission rates was examined in a retrospective cohort of 14,650 elderly patients (>65 years old) admitted to 11 ICUs in Winnipeg, Manitoba, Canada between 2000 and 2006. Logistic regression models were used to adjust odds of mortality and readmission to ICU for baseline case mix and illness severity. Results Elderly ESRD patients had twofold higher crude in-hospital mortality (22% versus 13%, P versus 2.7%, P = 0.001). After adjustment for illness severity alone or illness severity and case mix, the odds ratio for mortality decreased to 0.85 (95% CI: 0.57 to 1.25) and 0.82 (95% CI: 0.55 to 1.23), respectively. In contrast, ESRD status remained significantly associated with readmission to ICU after adjustment for other risk factors (OR 2.06 [95% CI: 1.32, 3.22]). Conclusions Illness severity on admission, rather than ESRD status per se , appears to be the main driver of in-hospital mortality in elderly patients. However, ESRD status is an independent risk factor for early and late readmission, suggesting that this population might benefit from alternative strategies for ICU discharge.

First Nations (FN) patients on peritoneal dialysis experience poor outcomes. Whether discrepancies exist regarding the microbiology, rate of infections, and outcomes between FN and non-FN peoples remains unknown. Design, setting, participants,measures: All adult peritoneal dialysis patients (n = 727) from 1997 to 2007 residing in Manitoba, Canada, were included. Parametric and nonparametric tests were used as necessary. Negative binomial regression was used to determine the relationship of rates of exit site infections (ESIs) and peritonitis between FN and non-FN peoples.A total of 161 FN and 566 non-FN subjects were included in the analyses. The unadjusted relative rates of peritonitis and ESIs in FN subjects were 132.7 and 86.0/100 patient-years compared with 87.8 and 78.2/100 patient-years in non-FN populations, respectively. FN subjects were more likely to have culture-negative peritonitis (36.5 versus 20.8%, P0.0001) and Staphylococcus ESIs (54.1 versus 32.9%, P0.0001). The crude and adjusted rates of peritonitis were higher in FN subjects for total episodes and culture-negative and gram-negative peritonitis. Catheter removal because of peritonitis was similar in both groups (42.9 versus 38.1% for FN and non-FN subjects, respectively; P = 0.261).FN patients experience higher rates of peritonitis and similar rates of ESIs compared with non-FN patients. Interventions to improve outcomes and prevent infections should specifically be targeted to the FN population.

Background. Observational and randomized controlled studies suggest that patients with stage 4 and 5 chronic kidney disease (CKD) derive morbidity and mortality benefit from being followed up in multidisciplinary, allied health clinics. It remains unclear how these clinics should be structured in order to optimize an efficient use of resources. The objectives of this study are (i) to describe ‘human’ resource utilization in an established ‘traditional’ multidisciplinary CKD clinic and (ii) to optimize efficiency and accountability of this multidisciplinary CKD clinic while maintaining or improving delivered quality of care. Methods. We conducted a prospective, cohort, intervention study in the multidisciplinary CKD clinics at a university-affiliated hospital in Winnipeg, Canada. There were 480 patients identified as requiring multidisciplinary care (68% male; 32% female; 64% Caucasian, 25% First Nations, 7% Asian; mean age 61), and the majority of these were in stages 4 and 5 CKD (80%). The aetiologies of CKD included diabetes (53%), hypertension (10%) and glomerulonephritis (GN) (19%). At baseline, process engineering analyses were conducted on resource use and workflows within the clinics. The intervention entailed clinic restructuring including changes to scheduling templates and documentation format as well as standardization of practitioner roles. Cross-sectional data to serve as surrogates for quality of care and efficiency were collected 1 year pre- and post-intervention. Results. Optimization of clinic structure did not significantly change the cycle times among nurses, dieticians and pharmacists, but nephrologists’ cycle time decreased from 13.8 min [interquartile range (IQR) 8–17] to 10.0 min (IQR 10–15) with P < 0.001. Patient throughput time decreased from 73 min (IQR 51–95) to 68.5 min (IQR 55–80). Compliance with established practice guidelines prior to clinic restructuring was 61% for BP (

A grid was developed to evaluate control of serum calcium, phosphate, and parathyroid hormone levels in hemodialysis patients, based on guideline recommendations (National Kidney Foundation Kidney Disease Outcomes Quality Initiative and Canadian Society of Nephrology), and its face validity was examined in a representative sample of Canadian patients. A retrospective chart review was undertaken in hemodialysis patients from 7 Canadian units. Patients >18 years, on hemodialysis for > or =12 months, and > or =3 parathyroid hormone levels measured > or =1 month apart were included. The grid classified mineral metabolism control as optimal, suboptimal, or poor (mean of 3 measurements). Medication use, hospitalization, and Emergency Department visits were evaluated in relation to grid occupancy. A second comparative analysis of grid occupancy was undertaken on prevalent hemodialysis cases in British Columbia in 2008. Data from 268 patients (mean age 62.3 years) were analyzed. Using National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines, 17.5%, 28.8%, and 53.7% of patients had optimal, suboptimal, and poor control, respectively, of all 3 parameters (calcium, phosphate, and parathyroid hormone). Using Canadian Society of Nephrology criteria, optimal, suboptimal, and poor control rates were 6.3%, 4.2%, and 89.5%, respectively. Poor control was a possible or a probable cause of hospitalization or Emergency Department attendance in 8 patients. Data from British Columbia in 2008 (n=1858) show optimal, suboptimal, and poor control rates of 15.8%, 24.5%, and 59.7%, respectively. Poor mineral metabolism control among Canadian hemodialysis patients is not showing improvement. The therapeutic grid is a valid tool and may help guide therapeutic decisions, quality control initiatives, and patient counseling. http://www.ukidney.com/bone-and-mineral-metabolism-resource.

Background Medication adherence in haemodialysis patients is often challenging due to a high pill burden, complex and dynamic medication regimens and limited patient self-interest in care. The purpose of this study was to investigate the time within target INR and safety profile of thrice weekly warfarin administration in haemodialysis patients with a clinical indication for anticoagulation and documented nonadherence to medications. Methods Thirty-seven patients from two haemodialysis units in Winnipeg, Manitoba, Canada, were recruited, and 17 patients were treated with thrice weekly warfarin and compared to 20 patients treated with daily warfarin therapy. The patients were followed for 1 year with weekly international normalized ratio (INR), dosage and adverse events recorded. The primary outcome was percentage of time with INR in target and sub ( 4)-therapeutic INR. Adverse events were recorded in the two groups. Results The thrice weekly group had a higher burden of comorbidity (Charlson comorbidity index of 6.35 +/- 1.77 versus 4.55 +/- 1.64, P = 0.003) compared to the daily dosage group. In the thrice weekly dosage group, time within target INR was higher (56.9 versus 49.3%, P = 0.008), and time with supra-therapeutic INR > 4 lower (2.7 versus 4.3%, P = 0.03). Total bleeding events (7 versus 6) and major bleeding events (3 versus 2 events) were similar between the two groups. Conclusion In this pilot study, thrice weekly warfarin appears to be a safe and feasible dosing strategy in a select patient population. A randomized controlled trial of thrice weekly warfarin is warranted.

Background The early evolution of acute kidney injury (AKI) in humans is difficult to study noninvasively. We hypothesized that urine proteomics could provide insight into the early pathophysiology of human AKI. Study Design A prospective nested case-control study (n = 250) compared serial urinary proteomes of 22 patients with AKI and 22 patients without AKI before, during, and after cardiopulmonary bypass surgery. Outcomes AKI was defined as a greater than 50% increase in serum creatinine level, and non-AKI, as less than 10% increase from baseline. Measurements Serum creatinine, urine protein-creatinine ratio, neutrophil gelatinase-associated lipocalin (NGAL), α 1 -microglobulin, interferon-inducible protein-10 (IP-10), monokine induced by interferon gamma (Mig), interferon-inducible T cell alpha chemoatractant (I-TAC), interleukin 6 (IL-6), IL-1β, and IL-10. Urine protein profiling by means of surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Results SELDI-TOF-MS showed intraoperative tubular stress in both groups on arrival to the intensive care unit, evidenced by β 2 -microglobulinuria. Non-AKI proteomes returned toward baseline postoperatively. In contrast, AKI proteomes showed a second phase of tubular injury/stress with the reappearance of β 2 -microglobulin and multiple unidentified peaks (3 to 5 and 6 to 8 kDa) and the appearance of established tubular injury markers: urinary protein, α 1 -microglobulin, and NGAL. Furthermore, 2 novel peaks (2.43 and 2.78 kDa) were found to be dominant in postoperative non-AKI urine samples. The 2.78-kDa protein was identified as the active 25–amino acid form of hepcidin (hepcidin-25), a key regulator of iron homeostasis. Finally, an inflammatory component of reperfusion injury was evaluated by means of enzyme-linked immunosorbent assay analysis of candidate chemokines (IP-10, I-TAC, and Mig) and cytokines (IL-6, IL-1β, and IL-10). Of these, IP-10 was upregulated in patients with versus without AKI postoperatively. Limitations This is an observational study. SELDI-TOF-MS is a semiquantitative technique. Conclusions Evaluation of human AKI revealed early intraoperative tubular stress in all patients. A second phase of injury observed in patients with AKI may involve IP-10 recruitment of inflammatory cells. The enhancement of hepcidin-25 in patients without AKI may suggest a novel role for iron sequestration in modulating AKI.

Background: Vascular calcification is believed to have a crucial role in the excess cardiovascular mortality and morbidity in patients with end-stage renal disease (ESRD). Methods and Results: Recent evidence suggests that uremic vascular calcification is an active cell-mediated process resembling osteogenesis in bone, rather than passive precipitation of calcium and phosphorus in the setting of deranged mineral metabolism. To date, several bone-associated proteins (osteopontin, bone sialoprotein, alkaline phosphatase, and type I collagen) have been shown in histological sections of vessels obtained from patients with ESRD or calcific uremic arteriolopathy. In in vitro experiments, the addition of uremic serum upregulates osteopontin expression by cultured vascular smooth muscle cells (VSMCs). Conclusion: We are only beginning to understand the process by which VSMCs transform into osteoblast-like cells, although phosphorus may have a key role. Additional factors mediating or modulating the development of vascular calcification in patients with ESRD remain to be identified. Further understanding of the pathophysiological state of uremic vascular calcification is needed to design effective therapeutic strategies to intervene with this devastating condition in the ESRD population. Am J Kidney Dis 41(S1):S96-S99. © 2003 by the National Kidney Foundation, Inc.

Background. The purpose of the present study was to determine the natural history of coronary artery and aorta calcification by spiral computed tomography (CT) in patients who undergo a renal transplant and patients on haemodialysis. Methods. Two cohorts were evaluated for the natural history of vascular calcification: (i) 23 patients who underwent a baseline CT scan at the time of renal transplant and a repeat evaluation 15–20 months later; and (ii) 33 chronic kidney disease, stage 5 haemodialysis subjects who underwent a baseline CT scan, all followed for a minimum of 15 months, and 17 of whom underwent a second CT scan. Results. In the patients undergoing a renal transplant, there was no net change in CAC with time, suggesting stabilization of calcification. In the haemodialysis patients, the median CAC increased by 1.27±1.88 score/days, P ¼ 0.013. There was a trend towards increasing AoC score in both groups. All patients without calcification at baseline remained calcification free at follow-up. In the 15 months following baseline, the six dialysis patients who died had a significantly greater CAC score at baseline compared with the 24 patients who remained alive. Similarly, those patients who were hospitalized had a greater baseline CAC than patients who were not hospitalized. Conclusion. In this preliminary study, renal transplantation appears to slow down or arrest CAC, whereas CAC progresses in haemodialysis patients. In haemodialysis patients, CAC was greater in patients who died or were hospitalized compared with those who remained alive or were not hospitalized.