Association Between Hospital Postoperative Troponin Use and Patient Outcomes After Vascular Surgery.

Background: Acute myocardial injury after noncardiac surgery, which is most often symptomatically silent, is associated with increased mortality and morbidity. However, it is not known if routine postoperative troponin testing will affect patient outcomes.

Methods: We assembled a cohort of patients who underwent carotid endarterectomy or abdominal aortic aneurysm repair in Ontario, Canada, from 2010 to 2017.

Troponin testing after noncardiac surgery: a population-based historical cohort study on variation and factors associated with testing in Ontario.

Background: International practice guidelines make different recommendations for postoperative troponin testing to detect perioperative myocardial infarction and myocardial injury after noncardiac surgery. To gain insights into current testing patterns, we evaluated predictors of routine troponin testing after three commonly performed major noncardiac surgeries.

Methods: We conducted a population-based historical cohort study of adults having major orthopedic, colorectal, or vascular surgery in Ontario, Canada from 1 January 2010 to 31 December 2017.

Adverse Fetal Outcomes and Maternal Mortality Following Nonobstetric Abdominopelvic Surgery in Pregnancy: A Systematic Review and Meta-analysis.

Objective: To quantify the absolute risks of adverse fetal outcomes and maternal mortality following nonobstetric abdominopelvic surgery in pregnancy.

Summary Background Data: Surgery is often necessary in pregnancy, but absolute measures of risk required to guide perioperative management are lacking.

Methods: We systematically searched MEDLINE, EMBASE, and EvidenceBased Medicine Reviews from January 1, 2000, to December 9, 2020, for observational studies and randomized trials of pregnant patients undergoing nonobstetric abdominopelvic surgery.

Renin-angiotensin-aldosterone system inhibitors and major cardiovascular events and acute kidney injury in patients with coronary artery disease.

Background: Renin-angiotensin-aldosterone system inhibitors (RAASIs) are recommended for most patients with coronary artery disease (CAD). However, there is debate across guidelines as to which patients with CAD benefit the most from these agents. This study investigated the association between RAASIs and cardiovascular outcomes and acute kidney injury in a contemporary cohort of patients with CAD.

Troponin Testing After Noncardiac Surgery in Ontario: An Observational Study.

Background: In 2017, the Canadian Cardiovascular Society (CCS) published guidelines recommending postoperative troponin surveillance in higher-risk patients having major noncardiac surgery. The objective of this study was to evaluate the proportion of major noncardiac surgery patients that would meet recommendations for troponin testing and to assess the rates of troponin testing before guideline adoption.

Methods: We conducted a retrospective observational study of patients age 40 to 105 undergoing a subset of major noncardiac surgeries that included orthopedics, gynecology, general, urology, vascular, and thoracic surgeries in Ontario, Canada from January 1, 2010 to December 31, 2017.

The cost-effectiveness of transcatheter aortic valve replacement in low surgical risk patients with severe aortic stenosis.

Aims: The economic value of transcatheter aortic valve replacement (TAVR) in low surgical risk patients with severe, symptomatic aortic stenosis is not known. Our objective was to determine the cost-effectiveness of balloon-expandable TAVR and self-expandable TAVR relative to surgical aortic valve replacement (SAVR) in low-risk patients.

Methods And Results: A fully probabilistic Markov cohort model was constructed to estimate differences in costs and effectiveness [quality-adjusted life years (QALYs)] over the patient's life-time time from the third-party payer's perspective.

Clinical Outcomes With Beta-Blocker Use in Patients With Recent History of Myocardial Infarction.

Background: It is uncertain whether beta-blockers (BBs) are beneficial in contemporary stable patients with prior myocardial infarction (MI). Therefore, we sought to examine the effectiveness of BB use in this population.

Methods: We conducted a cohort study with the use of administrative databases of patients ≥ 65 years of age, alive on April 1, 2012 (index date) with a hospital discharge diagnosis of MI within the previous 3 years.

Calibration and discrimination of the Framingham Risk Score and the Pooled Cohort Equations.

Background: Although accurate risk prediction is essential in guiding treatment decisions in primary prevention of atherosclerotic cardiovascular disease, the accuracy of the Framingham Risk Score (recommended by a Canadian guideline) and the Pooled Cohort Equations (recommended by US guidelines) has not been assessed in a large contemporary Canadian population. Our primary objective was to assess the calibration and discrimination of the Framingham Risk Score and Pooled Cohort Equations in Ontario, Canada.

Methods: We conducted an observational study involving Ontario residents aged 40 to 79 years, without a history of atherosclerotic cardiovascular disease, who underwent cholesterol testing and blood pressure measurement from Jan.

Evaluation of Machine Learning Algorithms for Predicting Readmission After Acute Myocardial Infarction Using Routinely Collected Clinical Data.

Background: The ability to predict readmission accurately after hospitalization for acute myocardial infarction (AMI) is limited in current statistical models. Machine-learning (ML) methods have shown improved predictive ability in various clinical contexts, but their utility in predicting readmission after hospitalization for AMI is unknown.

Methods: Using detailed clinical information collected from patients hospitalized with AMI, we evaluated 6 ML algorithms (logistic regression, naïve Bayes, support vector machines, random forest, gradient boosting, and deep neural networks) to predict readmission within 30 days and 1 year of discharge.

Comparative effectiveness of ACE inhibitors and angiotensin receptor blockers in patients with prior myocardial infarction.

Objective: Although ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are commonly prescribed for patients with coronary artery disease, whether these medications are similarly effective is still a subject of intense debate. Our objective was to compare the clinical effectiveness of ACEIs and ARBs in patients with prior myocardial infarction (MI).

Methods: All residents older than 65 years, alive on 1 April 2012, with a prior MI were included.

Left ventricular strain analysis using cardiac magnetic resonance imaging in patients undergoing in-centre nocturnal haemodialysis.

Aim: Intensified haemodialysis is associated with regression of left ventricular (LV) mass. Compared to LV ejection fraction, LV strain allows more direct assessment of LV function. We sought to assess the impact of in-centre nocturnal haemodialysis (INHD) on global LV strain (radial, circumferential, and longitudinal) and torsion by cardiac MRI (CMR).

Prostaglandin I2 Receptor Agonism Preserves β-Cell Function and Attenuates Albuminuria Through Nephrin-Dependent Mechanisms.

Discovery of common pathways that mediate both pancreatic β-cell function and end-organ function offers the opportunity to develop therapies that modulate glucose homeostasis and separately slow the development of diabetes complications. Here, we investigated the in vitro and in vivo effects of pharmacological agonism of the prostaglandin I2 (IP) receptor in pancreatic β-cells and in glomerular podocytes. The IP receptor agonist MRE-269 increased intracellular 3',5'-cyclic adenosine monophosphate (cAMP), augmented glucose-stimulated insulin secretion (GSIS), and increased viability in MIN6 β-cells.

A novel assay uncovers an unexpected role for SR-BI in LDL transcytosis.

Aims: Retention of low-density lipoprotein (LDL) cholesterol beneath the arterial endothelium initiates an inflammatory response culminating in atherosclerosis. Since the overlying endothelium is healthy and intact early on, it is likely that LDL passes through endothelial cells by transcytosis. However, technical challenges have made confirming this notion and elucidating the mechanisms of transcytosis difficult.

Palmitate-induced inflammatory pathways in human adipose microvascular endothelial cells promote monocyte adhesion and impair insulin transcytosis.

Obesity is associated with inflammation and immune cell recruitment to adipose tissue, muscle and intima of atherosclerotic blood vessels. Obesity and hyperlipidemia are also associated with tissue insulin resistance and can compromise insulin delivery to muscle. The muscle/fat microvascular endothelium mediates insulin delivery and facilitates monocyte transmigration, yet its contribution to the consequences of hyperlipidemia is poorly understood.

Clathrin-dependent entry and vesicle-mediated exocytosis define insulin transcytosis across microvascular endothelial cells.

Transport of insulin across the microvasculature is necessary to reach its target organs (e.g., adipose and muscle tissues) and is rate limiting in insulin action.

AMPK phosphorylation of ACC2 is required for skeletal muscle fatty acid oxidation and insulin sensitivity in mice.

Aims/hypothesis: Obesity is characterised by lipid accumulation in skeletal muscle, which increases the risk of developing insulin resistance and type 2 diabetes. AMP-activated protein kinase (AMPK) is a sensor of cellular energy status and is activated in skeletal muscle by exercise, hormones (leptin, adiponectin, IL-6) and pharmacological agents (5-amino-4-imidazolecarboxamide ribonucleoside [AICAR] and metformin). Phosphorylation of acetyl-CoA carboxylase 2 (ACC2) at S221 (S212 in mice) by AMPK reduces ACC activity and malonyl-CoA content but the importance of the AMPK-ACC2-malonyl-CoA pathway in controlling fatty acid metabolism and insulin sensitivity is not understood; therefore, we characterised Acc2 S212A knock-in (ACC2 KI) mice.