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Christopher T. Chan

Bio: Christopher T. Chan is an academic researcher from Toronto General Hospital. The author has contributed to research in topics: Hemodialysis & Home hemodialysis. The author has an hindex of 29, co-authored 49 publications receiving 4571 citations. Previous affiliations of Christopher T. Chan include University of Toronto & University Health Network.

Papers
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Journal ArticleDOI
25 Apr 2007-JAMA
TL;DR: RRT after cardiac surgery is predicted by readily available preoperative information and discriminated well between low- and high-risk patients in derivation and validation cohorts, and the index had improved generalizability when used to predict likelihood ratios for RRT.
Abstract: ContextA predictive index for renal replacement therapy (RRT; hemodialysis or continuous venovenous hemodiafiltration) after cardiac surgery may improve clinical decision making and research design.ObjectivesTo develop a predictive index for RRT using preoperative information.Design, Setting, and ParticipantsRetrospective cohort of 20 131 cardiac surgery patients at 2 hospitals in Ontario, Canada. The derivation cohort consisted of 10 751 patients at Toronto General Hospital (1999-2004). The validation cohorts consisted of 2566 patients at Toronto General Hospital (2004-2005) and 6814 patients at Ottawa Heart Institute (1999-2003).Main Outcome MeasurePostoperative RRT.ResultsRRT rates in the derivation, Toronto validation, and Ottawa validation cohorts were 1.3%, 1.8%, and 2.2%, respectively. Multivariable predictors of RRT were preoperative estimated glomerular filtration rate, diabetes mellitus requiring medication, left ventricular ejection fraction, previous cardiac surgery, procedure, urgency of surgery, and preoperative intra-aortic balloon pump. The predictive index was scored from 0 to 8 points. An estimated glomerular filtration rate less than or equal to 30 mL/min was assigned 2 points; other components were assigned 1 point each: estimated glomerular filtration rate 31 to 60 mL/min, diabetes mellitus, ejection fraction less than or equal to 40%, previous cardiac surgery, procedure other than coronary artery bypass grafting, intra-aortic balloon pump, and nonelective case. Among the 53% of patients with low risk scores (≤1), the risk of RRT was 0.4%; by comparison, this risk was 10% among the 6% of patients with high-risk scores (≥4). The predictive index had areas under the receiver operating characteristic curve in the derivation, Toronto validation, and Ottawa validation cohorts of 0.81, 0.78, and 0.78, respectively. When these cohorts were stratified based on index scores, likelihood ratios for RRT were more concordant than observed RRT rates.ConclusionsRRT after cardiac surgery is predicted by readily available preoperative information. A simple predictive index based on this information discriminated well between low- and high-risk patients in derivation and validation cohorts. The index had improved generalizability when used to predict likelihood ratios for RRT.

372 citations

Journal ArticleDOI
TL;DR: Reductions in BP with NHD are accompanied by regression of LVH, and there was no relationship between changes in LVMI and changes in BP or Hb in the CHD cohort.

360 citations

Journal ArticleDOI
TL;DR: It is concluded that pregnancy may be safe and feasible in women with ESRD receiving intensive hemodialysis.
Abstract: Pregnancy is rare in women with ESRD and when it occurs, it is often accompanied by significant maternal and fetal morbidity and even mortality. Preliminary data from the Toronto Nocturnal Hemodialysis Program suggested that increased clearance of uremic toxins by intensified hemodialysis improves pregnancy outcomes, but small numbers and the absence of a comparator group limited widespread applicability of these findings. We compared pregnancy outcomes from 22 pregnancies in the Toronto Pregnancy and Kidney Disease Clinic and Registry (2000–2013) with outcomes from 70 pregnancies in the American Registry for Pregnancy in Dialysis Patients (1990–2011). The primary outcome was the live birth rateandsecondaryoutcomesincludedgestationalageandbirthweight.ThelivebirthrateintheCanadian cohort (86.4%) was significantly higher than the rate in the American cohort (61.4%; P=0.03). Among patients with established ESRD, the median duration of pregnancy in the more intensively dialyzed Toronto cohort was 36 weeks (interquartile range, 32–37) compared with 27 weeks (interquartile range, 21–35) in the American cohort (P=0.002). Furthermore, a dose response between dialysis intensity and pregnancy outcomes emerged, with live birth rates of 48% in women dialyzed #20 hours per week and 85%inwomendialyzed.36hoursperweek(P=0.02),withalongergestationalageandgreaterinfantbirth weight for women dialyzed more intensively. Pregnancy complications were few and manageable. We conclude that pregnancy may be safe and feasible in women with ESRD receiving intensive hemodialysis.

225 citations


Cited by
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TL;DR: The guidelines focused on 4 key domains: (1) AKI definition, (2) prevention and treatment of AKI, (3) contrastinduced AKI (CI-AKI) and (4) dialysis interventions for the treatment ofAKI.
Abstract: tion’, implying that most patients ‘should’ receive a particular action. In contrast, level 2 guidelines are essentially ‘suggestions’ and are deemed to be ‘weak’ or discretionary, recognising that management decisions may vary in different clinical contexts. Each recommendation was further graded from A to D by the quality of evidence underpinning them, with grade A referring to a high quality of evidence whilst grade D recognised a ‘very low’ evidence base. The overall strength and quality of the supporting evidence is summarised in table 1 . The guidelines focused on 4 key domains: (1) AKI definition, (2) prevention and treatment of AKI, (3) contrastinduced AKI (CI-AKI) and (4) dialysis interventions for the treatment of AKI. The full summary of clinical practice statements is available at www.kdigo.org, but a few key recommendation statements will be highlighted here.

6,247 citations

Journal ArticleDOI
TL;DR: It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how (poly)phenol molecules interact with human physiological and pathological processes.
Abstract: Human intervention trials have provided evidence for protective effects of various (poly)phenol-rich foods against chronic disease, including cardiovascular disease, neurodegeneration, and cancer. While there are considerable data suggesting benefits of (poly)phenol intake, conclusions regarding their preventive potential remain unresolved due to several limitations in existing studies. Bioactivity investigations using cell lines have made an extensive use of both (poly)phenolic aglycones and sugar conjugates, these being the typical forms that exist in planta, at concentrations in the low-μM-to-mM range. However, after ingestion, dietary (poly)phenolics appear in the circulatory system not as the parent compounds, but as phase II metabolites, and their presence in plasma after dietary intake rarely exceeds nM concentrations. Substantial quantities of both the parent compounds and their metabolites pass to the colon where they are degraded by the action of the local microbiota, giving rise principally to small phenolic acid and aromatic catabolites that are absorbed into the circulatory system. This comprehensive review describes the different groups of compounds that have been reported to be involved in human nutrition, their fate in the body as they pass through the gastrointestinal tract and are absorbed into the circulatory system, the evidence of their impact on human chronic diseases, and the possible mechanisms of action through which (poly)phenol metabolites and catabolites may exert these protective actions. It is concluded that better performed in vivo intervention and in vitro mechanistic studies are needed to fully understand how these molecules interact with human physiological and pathological processes.

1,968 citations

Journal ArticleDOI
TL;DR: This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.
Abstract: Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

1,712 citations

Journal ArticleDOI
TL;DR: This work reviews three types of major long-term sequelae to severe OSA and discusses future research into understanding the pathophysiology of sleep apnea as a basis for uncovering newer forms of treatment of both the ventilatory disorder and its multiple sequelae.
Abstract: Sleep-induced apnea and disordered breathing refers to intermittent, cyclical cessations or reductions of airflow, with or without obstructions of the upper airway (OSA). In the presence of an anat...

1,608 citations