Alexander K.C. Leung

Prof. Alexander K.C. Leung

University of Calgary, Cumming School of Medicine, MD program
orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2020 in Canadian Journal of Cardiology
Verified
Journal Article
Closed access
DRDoreen M. Rabi
Doreen M. Rabi
KMKerry A. McBrien
Kerry A. McBrien
RSRuth Sapir-Pichhadze
Ruth Sapir-Pichhadze
MNMeranda Nakhla
Meranda Nakhla
SASofia B. Ahmed
Sofia B. Ahmed
SDStella S. Daskalopoulou
Stella S. Daskalopoulou

1 May 2018 in Canadian Journal of Cardiology
Verified
Journal Article
Open access
KNKara A. Nerenberg
Kara A. Nerenberg
KZKelly B. Zarnke
Kelly B. Zarnke
Alexander K.C. LeungAlexander K.C. Leung
Alexander K.C. Leung
KDKaberi Dasgupta
Kaberi Dasgupta
SBSonia Butalia
Sonia Butalia
SDStella S. Daskalopoulou
Stella S. Daskalopoulou
Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension in adults and children. This year, the adult and pediatric guidelines are combined in one document. The new 2018 pregnancy-specific hypertension guidelines are published separately. For 2018, 5 new guidelines are introduced, and 1 existing guideline on the blood pressure thresholds and targets in the setting of thrombolysis for acute ischemic stroke is revised. The use of validated wrist devices for the estimation of blood pressure in individuals with large arm circumference is now included. Guidance is provided for the follow-up measurements of blood pressure, with the use of standardized methods and electronic (oscillometric) upper arm devices in individuals with hypertension, and either ambulatory blood pressure monitoring or home blood pressure monitoring in individuals with white coat effect. We specify that all individuals with hypertension should have an assessment of global cardiovascular risk to promote health behaviours that lower blood pressure. Finally, an angiotensin receptor-neprilysin inhibitor combination should be used in place of either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in individuals with heart failure (with ejection fraction < 40%) who are symptomatic despite appropriate doses of guideline-directed heart failure therapies. The specific evidence and rationale underlying each of these guidelines are discussed.

2 June 2009 in Annals of Internal Medicine
Verified
Journal Article
Closed access
PDF file
FMFinlay McAlister
Finlay McAlister
NWNatasha Wiebe
Natasha Wiebe
JEJustin A. Ezekowitz
Justin A. Ezekowitz
Alexander K.C. LeungAlexander K.C. Leung
Alexander K.C. Leung
PAPaul W. Armstrong
Paul W. Armstrong
Guidelines recommend that patients with heart failure receive beta-blockers in doses used in the trials that have proven their efficacy. Although the adverse effects of beta-blockade are dose-related, it is unclear whether the benefits are. To determine whether the survival benefits of beta-blockade in heart failure are associated with the magnitude of heart rate reduction or the beta-blocker dose. MEDLINE, EMBASE, CINAHL, SIGLE, Web of Science, and the Cochrane Central Register of Controlled Trials, supplemented by hand-searches of bibliographies. Randomized, placebo-controlled heart failure trials that reported all-cause mortality. Two reviewers independently extracted data on study characteristics, beta-blocker dosing and heart rate reduction, and death. The mean left ventricular ejection fraction in the 23 beta-blocker trials ranged from 0.17 to 0.36, and more than 95% of the 19 209 patients had systolic dysfunction. The overall risk ratio for death was 0.76 (95% CI, 0.68 to 0.84); however, heterogeneity testing revealed moderate heterogeneity among trials (I (2) = 30%), which was associated with the magnitude of heart rate reduction achieved within each trial (P for meta-regression = 0.006). For every heart rate reduction of 5 beats/min with beta-blocker treatment, a commensurate 18% reduction (CI, 6% to 29%) in the risk for death occurred. No significant relationship between all-cause mortality and beta-blocker dosing was observed (risk ratio for death, 0.74 [CI, 0.64 to 0.86]) in high-dose beta-blocker trials vs. 0.78 [CI, 0.63 to 0.96] in low-dose beta-blocker trials; P for meta-regression = 0.69). The analysis is based on aggregate data and resting heart rates. Few patients in these trials had bradycardia or diastolic dysfunction at baseline. The magnitude of heart rate reduction is statistically significantly associated with the survival benefit of beta-blockers in heart failure, whereas the dose of beta-blocker is not.

25 February 2011 in Critical Care
Verified
Journal Article
Open access
PDF file
CKConstantine J Karvellas
Constantine J Karvellas
MFMaha R Farhat
Maha R Farhat
ISImran Sajjad
Imran Sajjad
SMSimon S Mogensen
Simon S Mogensen
Alexander K.C. LeungAlexander K.C. Leung
Alexander K.C. Leung
SBSean M Bagshaw
Sean M Bagshaw
Introduction: Our aim was to investigate the impact of early versus late initiation of renal replacement therapy (RRT) on clinical outcomes in critically ill patients with acute kidney injury (AKI). Methods: Systematic review and meta-analysis were used in this study. PUBMED, EMBASE, SCOPUS, Web of Science and Cochrane Central Registry of Controlled Clinical Trials, and other sources were searched in July 2010. Eligible studies selected were cohort and randomised trials that assessed timing of initiation of RRT in critically ill adults with AKI. Results: We identified 15 unique studies (2 randomised, 4 prospective cohort, 9 retrospective cohort) out of 1,494 citations. The overall methodological quality was low. Early, compared with late therapy, was associated with a significant improvement in 28-day mortality (odds ratio (OR) 0.45; 95% confidence interval (CI), 0.28 to 0.72). There was significant heterogeneity among the 15 pooled studies (I2 = 78%). In subgroup analyses, stratifying by patient population (surgical, n = 8 vs. mixed, n = 7) or study design (prospective, n = 10 vs. retrospective, n = 5), there was no impact on the overall summary estimate for mortality. Meta-regression controlling for illness severity (Acute Physiology And Chronic Health Evaluation II (APACHE II)), baseline creatinine and urea did not impact the overall summary estimate for mortality. Of studies reporting secondary outcomes, five studies (out of seven) reported greater renal recovery, seven (out of eight) studies showed decreased duration of RRT and five (out of six) studies showed decreased ICU length of stay in the early, compared with late, RRT group. Early RRT did not; however, significantly affect the odds of dialysis dependence beyond hospitalization (OR 0.62 0.34 to 1.13, I2 = 69.6%). Conclusions: Earlier institution of RRT in critically ill patients with AKI may have a beneficial impact on survival. However, this conclusion is based on heterogeneous studies of variable quality and only two randomised trials. In the absence of new evidence from suitably-designed randomised trials, a definitive treatment recommendation cannot be made.

1 May 2016 in Canadian Journal of Cardiology
Verified
Journal Article
Closed access
Alexander K.C. LeungAlexander K.C. Leung
Alexander K.C. Leung
KNKara Nerenberg
Kara Nerenberg
SDStella S. Daskalopoulou
Stella S. Daskalopoulou
KMKerry McBrien
Kerry McBrien
KZKelly B. Zarnke
Kelly B. Zarnke
DRDoreen M. Rabi
Doreen M. Rabi

24 February 2020 in BMJ
Verified
Journal Article
Open access
PDF file
LHLiping Huang
Liping Huang
KTKathy Trieu
Kathy Trieu
SYSohei Yoshimura
Sohei Yoshimura
BNBruce Neal
Bruce Neal
MWMark Woodward
Mark Woodward
FHFeng He
Feng He
Objective: To examine the dose-response relation between reduction in dietary sodium and blood pressure change and to explore the impact of intervention duration.Design: Systematic review and meta-analysis following PRISMA guidelines.Data sources: Ovid MEDLINE(R), EMBASE, and Cochrane Central Register of Controlled Trials (Wiley) and reference lists of relevant articles up to 21 January 2019.Inclusion criteria: Randomised trials comparing different levels of sodium intake undertaken among adult populations with estimates of intake made using 24 hour urinary sodium excretion.Data extraction and analysis: Two of three reviewers screened the records independently for eligibility. One reviewer extracted all data and the other two reviewed the data for accuracy. Reviewers performed random effects meta-analyses, subgroup analyses, and meta-regression.Results: 133 studies with 12 197 participants were included. The mean reductions (reduced sodiumvusual sodium) of 24 hour urinary sodium, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were 130 mmol (95% confidence interval 115 to 145, P<0.001), 4.26 mm Hg (3.62 to 4.89, P<0.001), and 2.07 mm Hg (1.67 to 2.48, P<0.001), respectively. Each 50 mmol reduction in 24 hour sodium excretion was associated with a 1.10 mm Hg (0.66 to 1.54; P<0.001) reduction in SBP and a 0.33 mm Hg (0.04 to 0.63; P=0.03) reduction in DBP. Reductions in blood pressure were observed in diverse population subsets examined, including hypertensive and non-hypertensive individuals. For the same reduction in 24 hour urinary sodium there was greater SBP reduction in older people, non-white populations, and those with higher baseline SBP levels. In trials of less than 15 days’ duration, each 50 mmol reduction in 24 hour urinary sodium excretion was associated with a 1.05 mm Hg (0.40 to 1.70; P=0.002) SBP fall, less than half the effect observed in studies of longer duration (2.13 mm Hg; 0.85 to 3.40; P=0.002). Otherwise, there was no association between trial duration and SBP reduction.Conclusions: The magnitude of blood pressure lowering achieved with sodium reduction showed a dose-response relation and was greater for older populations, non-white populations, and those with higher blood pressure. Short term studies underestimate the effect of sodium reduction on blood pressure.Systematic review registration: PROSPERO CRD42019140812.