Browsing by Author "Anderson, Todd J."

Now showing 1 - 8 of 8
  • Thumbnail Image
    ItemOpen Access
    Cardiovascular Consequences of Hypertensive Disorders of Pregnancy
    (2020-01) Wen, Chuan; Anderson, Todd J.; Nerenberg, Kara A.; Metcalfe, Amy; Johnson, Jo-Ann M.; Signal, Ronald J.; Tomfohr-Madsen, Lianne M.; McDonald, Sarah
    Hypertensive disorders of pregnancy (HDP), including preeclampsia and gestational hypertension (GHTN), are independently associated with increased maternal cardiovascular risk. Endothelial dysfunction is one of the crucial pathophysiology of preeclampsia and might be the connection between preeclampsia and future cardiovascular risk. The postpartum period offers a time window to identify and begin to manage modifiable cardiovascular risk factors. However, limited studies have focused on the first years postpartum and the opportunity for early cardiovascular prevention may be lost. Few studies have longitudinally observed the changes of vascular function by different measures. The aims of this study were to detect: Subsequent hypertension, diabetes and dyslipidemia in women with/without HDP over the first years postpartum by linking three administrative databases. The alterations of vascular function during pregnancy by using flow-mediated vasodilation (FMD), hyperemic velocity-time integral (VTI) and peripheral artery tonometry (PAT), and the relationship between vascular function indices and utero-placental ultrasonographic and biochemical markers. Our results highlighted women with HDP had higher odds of hypertension (GHTN adjusted OR [aOR]: 5.82[4.96-6.83]; preeclampsia: aOR: 4.97[3.63-6.81]), dyslipidemia (GHTN: aOR: 2.22[1.47-3.35]; preeclampsia: aOR: 1.41[1.10-1.80]), and diabetes (GHTN: aOR: 2.26[1.50, 13.4]; PE: 2.02[0.91, 4.46]) during 4 years postpartum than the normotensive pregnancy. Half of the women with HDP had no lipid testing. They were not more likely to be tested than normotensive women after adjusting for confounders. Women with GHTN and preeclampsia had less favorable and more atherogenic lab results than the normal controls. Non-significant changes of FMD and hyperemic VTI over pregnancy were detected. The PAT index declined consistently during pregnancy and this may have been related to vasodilator changes of baseline pulse wave amplitude. The uterine artery pulsatility index (UtA-PI) was not correlated with the standard measures of endothelial function. There were mild correlations between UtA-PI and baseline flow, sFlT-1 and ln(sFlt-1/PlGF ratio) with baseline flow and baseline VTI in the first trimester. Our study implies the needs of early postpartum screening for hypertension, dyslipidemia and dysglycemia in women with HDP. FMD, hyperemic VTI and PAT index might not be directly used as markers to represent the macrovascular and microvascular function during pregnancy.
  • Thumbnail Image
    ItemOpen Access
    Correction to: Guideline LDL-C Threshold Achievement in Acute Myocardial Infarction Patients: A Real-World Evidence Study Demonstrating the Impact of Treatment Intensification with PCSK9i
    (2023-03-15) Mackinnon, Erin S.; Har, Bryan; Champsi, Salimah; Wani, Rajvi J.; Geyer, Lee; Shaw, Eileen; Farris, Megan S.; Anderson, Todd J.
  • Thumbnail Image
    ItemOpen Access
    Electrocardiographic Parameters in the Assessment of Myocardial Fibrosis and Left Ventricular Systolic Function
    (2016) Narous, Mariam; Exner, Derek V.; Anderson, Todd J.; Fine, Nowell M.; White, James A.
    Assessment of cardiac structure and function is central to the care of patients with heart disease. Cardiac magnetic resonance (CMR) is the gold standard for such assessment, however it is expensive and oftentimes not readily accessible. We sought to evaluate the utility of electrocardiographic (ECG) and impedance-based parameters in estimating the amount of myocardial scar, left ventricular (LV) systolic function and myocardial deformation. Consecutive patients (n = 241; 42% female; mean age 55 years) undergoing clinical CMR and ECG assessments were recruited. ECG analysis was performed manually, using both the Modified Selvester Score (MSS) and the presence of fractionated QRS (fQRS) signals, and impedance testing using the Non-Invasive Cardiac System (NICaS). While MCS was of value, neither fQRS nor NICaS meaningfully predicted scar extent, LV systolic function. Or the amount of myocardial deformation. These results support additional investigation of the utility of the MSS in estimating cardiac structure and function among patients in whom cardiac imaging is clinically indicated.
  • Thumbnail Image
    ItemOpen Access
    Guideline LDL-C Threshold Achievement in Acute Myocardial Infarction Patients: A Real-World Evidence Study Demonstrating the Impact of Treatment Intensification with PCSK9i
    (2023-01-19) Mackinnon, Erin S.; Har, Bryan; Champsi, Salimah; Wani, Rajvi J.; Geyer, Lee; Shaw, Eileen; Farris, Megan S.; Anderson, Todd J.
    Abstract Introduction A high proportion of Canadian patients with acute myocardial infarction (AMI) do not achieve the threshold low-density lipoprotein cholesterol (LDL-C) levels recommended by the Canadian Cardiovascular Society in 2021. This increases the risk of subsequent atherosclerotic cardiovascular disease (ASCVD) events. Here, we assess LDL-C levels and threshold achievement among patients by lipid-lowering therapies (LLT) received post-AMI. Methods A retrospective cohort study of patients identified with AMI between 2015 and 2019 was conducted using administrative health databases in Alberta, Canada. Patients were grouped by their highest-intensity LLT post-AMI (proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) + another LLT; PCSK9i alone; ezetimibe + statin; statins (high, moderate, low intensity); or ezetimibe alone), and available LDL-C levels were examined in the year before and after LLT dispense date. Results The cohort included 15,283 patients. In patients on PCSK9i + LLT, the median [95% confidence interval (CI)] LDL-C levels decreased from 2.7 (2.3–3.4) before to 0.9 (0.5–1.2) mmol/l after treatment, the largest decrease among treatment groups. In the ezetimibe + statin and high-intensity statin groups, median (95% CI) values after treatment were 1.5 (1.5–1.6) and 1.4 (1.4–1.4) mmol/l, respectively. The proportion of patients below the 1.8 mmol/l threshold increased by 77.7% in the PSCK9i + LLT group after treatment, compared to 45.4 and 32.4% in the ezetimibe + statin and high-intensity statin groups, respectively. Conclusions Intensification with PCSK9i in AMI patients results in a greater proportion of patients achieving below the recommended LDL-C threshold versus statins and or ezetimibe alone. Increased focus on achieving below the LDL-C thresholds with additional LLT as required may benefit patient cardiovascular outcomes.
  • Thumbnail Image
    ItemOpen Access
    Impact of Intermittent Hypoxia on Human Cardiorespiratory and Cerebrovascular Function
    (2016) Beaudin, Andrew Edward; Poulin, Marc J.; Hanly, Patrick J.; Wilson, Richard J. A.; Anderson, Todd J.; Thompson, Roger J.; Horner, Richard L.
    Obstructive sleep apnoea (OSA) is a chronic sleep disorder characterized by intermittent hypoxia (IH) exposure during sleep and is an independent risk factor for cardiovascular and cerebrovascular disease. IH in untreated OSA is advanced as the principal pathway leading to the greater risk of vascular disease associated with OSA. Additionally, IH is implicated in the propagation of OSA severity by increasing ventilatory instability, in part, by enhancing ventilatory chemosensitivity. Therefore, the focus of this thesis was to investigate the mechanisms through which IH functions and the role of IH in disrupting vascular and ventilatory regulation in OSA. The molecular pathways through which IH disrupts vascular and ventilatory regulation are poorly understood, but IH-induced inflammation is believed to be a primary contributor. Using a human experimental model of IH during wakefulness and a clinical population of untreated OSA patients, Study 1 investigated the role of cyclooxygenase (COX)-1 and COX-2 derived prostanoids (mediators of the inflammatory response and vascular regulation) in IH-induced alterations in cardiovascular and cerebrovascular regulation. Additionally, Study 2 examined the role of inflammation in IH-induced respiratory plasticity. Study 3 investigated the effects of nocturnal oxygen therapy (to remove IH) and continuous positive airway pressure (CPAP; gold standard OSA treatment) on cardiorespiratory and cerebrovascular responses to hypoxia in newly diagnosed OSA patients. Finally, Study 4 assessed the feasibility of adapting our human IH model to sleep while incorporating the ability to assess cardiovascular and cerebrovascular responses to hypoxia and hypercapnia during sleep. Studies 1-3 add substantial knowledge to this important area of research. Specifically, they reveal that 1) cyclooxygenase (COX)-1 and COX-2 differentially regulate blood pressure and cerebrovascular responses to acute and chronic IH; 2) inflammation does not contribute to IH-induced respiratory plasticity following an acute (6h) IH exposure; and 3) both nocturnal oxygen and CPAP treatment of OSA may lower blood pressure during isocapnic-euoxia and the hypoxic ventilatory response, but neither modality effects vascular responses to hypoxia. Lastly, Study 4 showed it is feasible to apply our human IH model to sleep and to concurrently assess vascular responses to hypoxia and hypercapnia during sleep.
  • Thumbnail Image
    ItemOpen Access
  • Thumbnail Image
    ItemOpen Access
    Obesity and cardiovascular disease: a multi-modality approach
    (2012) Martin, Billie-Jean; Anderson, Todd J.; Ghali, William
  • Thumbnail Image
    ItemOpen Access
    The Brain in Motion II Study: study protocol for a randomized controlled trial of an aerobic exercise intervention for older adults at increased risk of dementia
    (2021-06-14) Krüger, Renata L.; Clark, Cameron M.; Dyck, Adrienna M.; Anderson, Todd J.; Clement, Fiona; Hanly, Patrick J.; Hanson, Heather M.; Hill, Michael D.; Hogan, David B.; Holroyd-Leduc, Jayna; Longman, R. S.; McDonough, Meghan; Pike, G. B.; Rawling, Jean M.; Sajobi, Tolulope; Poulin, Marc J.
    Abstract Background There remains no effective intervention capable of reversing most cases of dementia. Current research is focused on prevention by addressing risk factors that are shared between cardiovascular disease and dementia (e.g., hypertension) before the cognitive, functional, and behavioural symptoms of dementia manifest. A promising preventive treatment is exercise. This study describes the methods of a randomized controlled trial (RCT) that assesses the effects of aerobic exercise and behavioural support interventions in older adults at increased risk of dementia due to genetic and/or cardiovascular risk factors. The specific aims are to determine the effect of aerobic exercise on cognitive performance, explore the biological mechanisms that influence cognitive performance after exercise training, and determine if changes in cerebrovascular physiology and function persist 1 year after a 6-month aerobic exercise intervention followed by a 1-year behavioural support programme (at 18 months). Methods We will recruit 264 participants (aged 50–80 years) at elevated risk of dementia. Participants will be randomly allocated into one of four treatment arms: (1) aerobic exercise and health behaviour support, (2) aerobic exercise and no health behaviour support, (3) stretching-toning and health behaviour support, and (4) stretching-toning and no health behaviour support. The aerobic exercise intervention will consist of three supervised walking/jogging sessions per week for 6 months, whereas the stretching-toning control intervention will consist of three supervised stretching-toning sessions per week also for 6 months. Following the exercise interventions, participants will receive either 1 year of ongoing telephone behavioural support or no telephone support. The primary aim is to determine the independent effect of aerobic exercise on a cognitive composite score in participants allocated to this intervention compared to participants allocated to the stretching-toning group. The secondary aims are to examine the effects of aerobic exercise on a number of secondary outcomes and determine whether aerobic exercise-related changes persist after a 1-year behavioural support programme (at 18 months). Discussion This study will address knowledge gaps regarding the underlying mechanisms of the pro-cognitive effects of exercise by examining the potential mediating factors, including cerebrovascular/physiological, neuroimaging, sleep, and genetic factors that will provide novel biologic evidence on how aerobic exercise can prevent declines in cognition with ageing. Trial registration ClinicalTrials.gov NCT03035851 . Registered on 30 January 2017