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Myocardial infarction (MI) remains a leading cause of morbidity and mortality. In atherothrombotic MI (ST-elevation MI and type 1 non-ST-elevation MI), coronary artery occlusion leads to ischemia. Subsequent cardiomyocyte necrosis evolves over time as a wavefront within the territory at risk. The spectrum of ischemia and reperfusion injury is wide: it can be minimal in aborted MI or myocardial necrosis can be large and complicated by microvascular obstruction and reperfusion hemorrhage. Established risk scores and infarct classifications help with patient management but do not consider tissue injury characteristics. This document outlines the Canadian Cardiovascular Society classification of acute MI. It is an expert consensus formed on the basis of decades of data on atherothrombotic MI with reperfusion therapy. Four stages of progressively worsening myocardial tissue injury are identified: (1) aborted MI (no/minimal myocardial necrosis); (2) MI with significant cardiomyocyte necrosis, but without microvascular injury; (3) cardiomyocyte necrosis and microvascular dysfunction leading to microvascular obstruction (ie, "no-reflow"); and (4) cardiomyocyte and microvascular necrosis leading to reperfusion hemorrhage. Each stage reflects progression of tissue pathology of myocardial ischemia and reperfusion injury from the previous stage. Clinical studies have shown worse remodeling and increase in adverse clinical outcomes with progressive injury. Notably, microvascular injury is of particular importance, with the most severe form (hemorrhagic MI) leading to infarct expansion and risk of mechanical complications. This classification has the potential to stratify risk in MI patients and lay the groundwork for development of new, injury stage-specific and tissue pathology-based therapies for MI., (Copyright © 2023 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Magnetic resonance imaging (MRI) is often considered the gold-standard test for characterizing cardiac as well as noncardiac structure and function. However, many patients with cardiac implantable electronic devices (CIEDs) and/or severe renal dysfunction are unable to undergo this test because of safety concerns. In the past 10 years, newer-generation CIEDs and gadolinium-based contrast agents (GBCAs) as well as coordinated care between imaging and heart rhythm device teams have mitigated risk to patients and improved access to MRI at many hospitals. The purpose of this statement is to review published data on safety of MRI in patients with conditional and nonconditional CIEDs in addition to patient risks from older and newer GBCAs. This statement was developed through multidisciplinary collaboration of pan-Canadian experts after a relevant and independent literature search by the Canadian Agency for Drugs and Technologies in Health. All recommendations align with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Key recommendations include: (1) the development of standardized protocols for patients with a CIED undergoing MRI; (2) patients with MRI nonconditional pacemakers and pacemaker dependency should be programmed to asynchronous mode and those with MRI nonconditional transvenous defibrillators should have tachycardia therapies turned off during the scan; and (3) macrocyclic or newer linear GBCAs should be used in preference to older GBCAs because of their better safety profile in patients at higher risk of nephrogenic systemic fibrosis., (Copyright © 2021 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The impact of Fontan circuit thrombus is poorly understood. The objectives of this study were to determine (1) the incidence of Fontan circuit thrombus and proportion of silent thrombus; (2) any association between Fontan circuit thrombus and markers of Fontan circulatory dysfunction; and (3) the association of Fontan circuit thrombus with adverse cardiac outcomes., Methods: We conducted a retrospective review of adult patients who underwent the Fontan procedure (aged > 18 years) followed at St. Paul's Hospital who underwent cardiac computed tomography or magnetic resonance imaging assessment (n = 67). Fontan circulatory dysfunction markers included clinical heart failure, N-terminal pro-brain natriuretic peptide, ventricular dysfunction, atrioventricular valvular regurgitation, refractory arrhythmias, declining exercise capacity, and hepatic/renal dysfunction. Adverse cardiac outcomes were death, heart transplantation, or surgery for Fontan revision or atrioventricular valve replacement., Results: Fontan circuit thrombus was present in 15 of 67 patients (22%): 41% (7/17) classic/modified Fontan and 16% (8/50) total cavopulmonary connection. Incidence was 36% among those suspected to have Fontan circuit thrombus; 14% in those with no clinical/echocardiographic suspicion; and clinically silent in 40% diagnosed with Fontan thrombus. The time from Fontan surgery to Fontan circuit thrombus diagnosis was 22 ± 6 years in the classic/modified group vs 14 ± 8 years in the total cavopulmonary connection group (P = 0.03. Fontan circuit thrombus was associated with adverse cardiac outcomes (27% [4/15] vs 8% [4/52], P = 0.02), but there was no difference in Fontan circulatory dysfunction markers., Conclusion: Given the incidence of Fontan circuit thrombus and association with adverse cardiac outcomes, routine surveillance of the Fontan circuit should strongly be considered. The identification of thrombus should lead to anticoagulation implementation/optimization, along with screening/intervention for reversible Fontan circulatory issues in an attempt to prevent adverse cardiac outcomes., (Copyright © 2019 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Transcatheter aortic valve implantation (TAVI) or replacement has rapidly changed the treatment of patients with severe symptomatic aortic stenosis. It is now the standard of care for patients believed to be inoperable or at high surgical risk, and a reasonable alternative to surgical aortic valve replacement for those at intermediate surgical risk. Recent clinical trial data have shown the benefits of this technology in patients at low surgical risk as well. This update of the 2012 Canadian Cardiovascular Society TAVI position statement incorporates clinical evidence to provide a practical framework for patient selection that does not rely on surgical risk scores but rather on individual patient evaluation of risk and benefit from either TAVI or surgical aortic valve replacement. In addition, this statement features new wait time categories and treatment time goals for patients accepted for TAVI. Institutional requirements and recommendations for operator training and maintenance of competency have also been revised to reflect current standards. Procedural considerations such as decision-making for concomitant coronary intervention, antiplatelet therapy after intervention, and follow-up guidelines are also discussed. Finally, we suggest that all patients with aortic stenosis might benefit from evaluation by the heart team to determine the optimal individualized treatment decision., (Copyright © 2019 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

The complementary modalities of Doppler echocardiography and multidetector computed tomography are most frequently used for the planning and follow-up of transcatheter aortic valve replacement (TAVR). TAVR is now a well-established modality in the treatment of high-risk and inoperable patients with symptomatic severe aortic stenosis. Furthermore, recent studies have shown that TAVR is equivalent or superior to surgical aortic valve replacement in patients at intermediate surgical risk. We review the most commonly used imaging modalities and discuss their respective strengths and contributions to optimal patient selection, procedure planning, implementation, and follow-up in TAVR., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: We sought to assess the relationships between left ventricular (LV) remodelling and the mechanical and uremic stressors in hemodialysis patients., Methods: In this prospective 2-centre cohort study, 67 prevalent hemodialysis patients were followed for 1 year. Data on routine bloodwork and predialysis blood pressure (BP) measurements were collected over a 12-week period. LV end-diastolic volume (LVEDV) and LV mass (LVM) were measured using cardiac magnetic resonance imaging and indexed. High-sensitivity troponin-I (hsTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), fibroblast growth factor 23 (FGF-23), and high-sensitivity C-reactive protein (hsCRP) were also measured. All study procedures were performed at baseline and at 1 year. We examined the relationships between LV remodelling and (1) NT-proBNP and hsTnI (LV stretch and injury); (2) ultrafiltration volume (UFV) and interdialytic weight gain (IDWT; volume overload); (3) predialysis BP measurements (pressure overload); and (4) biomarkers of inflammation (hsCRP) and fibrosis (FGF-23)., Results: LVEDV was significantly associated with UFV and with IDWT, at baseline as well as at 1 year. NT-proBNP was significantly and negatively correlated with UFV and IDWT, respectively, at 1 year. There were significant correlations between systolic BP and LVM index, at baseline and at 1 year as well as longitudinally. Systolic BP was the only parameter longitudinally correlated with LVM/LVEDV. hsTnI was not associated with urea, parathyroid hormone, calcium, phosphorus, FGF-23, hsCRP, or hemoglobin., Conclusions: We did not observe significant relationships between myocardial injury and markers of fibrosis, inflammation, and LV remodelling. Elevated predialysis systolic BP, which might represent a common mediator of pressure and volume overload, appears to be a dominant stimulus for LV remodelling., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

In the treatment of stable coronary artery disease (CAD), the determination of stenosis severity by invasive coronary angiography (ICA) is a critical procedure, and for borderline lesions, the detection of ischemia through invasive fractional flow reserve (FFR) is the gold standard. With advances in computational fluid dynamics, FFR can now be calculated noninvasively using anatomic data from coronary computed tomographic angiography (CCTA). This technique is known as FFR CT . The purpose of this review is to summarize the science of FFR CT , describe its diagnostic accuracy, discuss its clinical and economic impact, and elucidate factors beyond stenosis severity that may mechanistically relate to lesion-specific ischemia. These factors include adverse atherosclerotic plaque characteristics such as positive remodelling, low-attenuation plaque, and spotty calcification, as well as aggregate plaque volume. These factors can be appreciated noninvasively by CCTA but not by ICA. The diagnostic accuracy of FFR CT , compared with the gold standard of FFR, has been validated in 3 prospective multicentre blinded core laboratory-controlled trials, and as a result FFR CT has been approved by the US Food and Drug Administration for clinical use. FFR CT has also been shown in a clinical utility trial to better identify patients without obstructive CAD when compared with standard noninvasive assessment of stable CAD, thereby avoiding unnecessary angiograms. In addition, the use of FFR CT has been shown to allow for a significant cost savings compared with traditional care. It is therefore important for cardiologists to appreciate the value of this important new methodology., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: In-centre nocturnal hemodialysis (INHD, 7-8 hours/session, 3 times/week) is an increasingly utilized form of dialysis intensification, though data on the cardiovascular benefits of this modality are limited., Methods: In this prospective cohort study, we enrolled 67 prevalent conventional hemodialysis (CHD, 4 hours/session, 3 times/week) recipients at 2 medical centres in Canada, of whom 37 converted to INHD and 30 remained on CHD. The primary outcome was the change in left ventricular mass (LVM) after 1 year as assessed by cardiac magnetic resonance imaging. Secondary outcomes included changes in serum phosphate concentration, phosphate binder burden, haemoglobin, erythropoiesis stimulating agent usage, and blood pressure., Results: Conversion to INHD was associated with a 14.2 (95% confidence interval [CI] 1.2-27.2) g reduction in LVM as compared with continuation on CHD. This result was maintained after adjustment for baseline imbalances between the groups and in ancillary analyses. There was a trend toward a larger drop in systolic blood pressure (9.8 [95% CI, -1.4-20.9] mm Hg) among INHD recipients with a significant reduction in the number of prescribed antihypertensive agents (0.7 [95% CI, 0.3-1.1] agents). Serum phosphate declined by 0.40 (95% CI, 0.16-0.63) mmol/L among INHD recipients without any difference in calcium-based phosphate binder requirements, as compared with those who remained on CHD., Conclusions: Compared with continuation of CHD, conversion to INHD was associated with significant LVM regression and reduction in serum phosphate concentration at 1 year., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Magnetic resonance imaging (MRI) has historically been considered contraindicated for individuals with cardiac implantable electronic devices (CIEDs) such as pacemakers and implantable defibrillators. Magnetic resonance scanners produce magnetic fields that can interact negatively with the metallic components of CIEDs. However, as CIED technology has advanced, newer MRI conditional devices have been developed that are now in clinical use and these systems have had demonstrated safety in the MRI environment. Despite the supportive data of such CIED systems, physicians remain reluctant to perform MRI scanning of conditional devices. This joint statement by the Canadian Heart Rhythm Society and the Canadian Association of Radiologists describes a collaborative process by which CIED specialists and clinics can work with radiology departments and specialists to safely perform MRI in patients with MRI conditional CIED systems. The steps required for patient and scanning preparation and the roles and responsibilities of the CIED and radiology departments are outlined. We also briefly outline the risks and a process by which patients with nonconditional CIEDs might also receive MRI in highly specialized centres. This document supports MRI in patients with MRI conditional CIEDs and offers recommendations on how this can be implemented safely and effectively., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

This Canadian Cardiovascular Society position statement aims to provide succinct perspectives on key issues in the management of thoracic aortic disease (TAD). This document is not a comprehensive overview of TAD and important elements of the epidemiology, presentation, diagnosis, and management of acute aortic syndromes are deliberately not discussed; readers are referred to the 2010 guidelines published by the American Heart Association, American College of Cardiology, American Association for Thoracic Surgery, and other stakeholders. Rather, this document is a practical guide for clinicians managing adult patients with TAD. Topics covered include size thresholds for surgical intervention, emerging therapies, imaging modalities, medical and lifestyle management, and genetics of TAD. The primary panel consisted of experts from a variety of disciplines that are essential for comprehensive management of TAD patients. The methodology involved a focused literature review with an emphasis on updates since 2010 and the use of Grading of Recommendations Assessment, Development, and Evaluation methodology to arrive at specific recommendations. The final document then underwent review by a secondary panel. This document aims to provide recommendations for most patients and situations. However, the ultimate judgement regarding the management of any individual patients should be made by their health care team., (Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Detailed multimodality assessment of subclinical atherosclerosis in asymptomatic subjects referred for risk stratification has not been performed. We analyzed the detection of early atherosclerosis using 3 imaging modalities: coronary artery calcium (CAC) scoring, carotid ultrasound (US), and coronary computed tomography angiography (CCTA)., Methods: Asymptomatic subjects free of known vascular disease scheduled to undergo a carotid US for risk stratification were invited to undergo CCTA/CAC. Subjects taking lipid-lowering medication were excluded. All images were assessed by experienced core laboratory personnel. Carotid intima media thickness ≥ 75th percentile for age and sex, CAC > 0, and detection of either carotid or coronary artery plaque were indicators of atherosclerosis., Results: Fifty patients were included with a median age of 53 years. Atherosclerosis was observed in 28%, 78%, and 90% of subjects using CAC, CCTA, and carotid US, respectively. All subjects showed atherosclerosis on at least 1 modality. In 36 patients with a CAC score = 0, 69% and 86% had atherosclerosis on CCTA and carotid US, respectively., Conclusions: In this detailed analysis, all subjects identified to warrant further risk stratification had subclinical atherosclerosis on at least 1 imaging modality. Concordance between modalities was highly variable, dependent on the specific definition of atherosclerosis used. Carotid US and CCTA detection of plaque were significantly more sensitive than CAC > 0 in this middle-aged population. Considering the prevalence of subclinical disease on carotid US and CCTA, the threshold at which to treat warrants further research., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Exposure to ionizing radiation is a consequence of many diagnostic and interventional cardiac procedures. Radiation exposure can result in detrimental health effects because of deterministic (eg, skin reaction) and stochastic effects (eg, cancer). However, with the levels experienced during cardiac procedures these risks can be difficult to quantify. Healthcare providers and patients might not fully appreciate radiation-related risks. Though in many cases radiation exposure cannot be avoided, a practice of minimizing exposures to levels "as low as reasonably achievable" (ALARA principle) without compromising the utility of the procedure is encouraged. The purpose of this document is to inform health care providers on the key concepts related to radiation risk from common cardiac procedures and provide specific recommendations on ensuring quality of care., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Although the clinical use of computed tomography in cardiac imaging had slow beginnings, it has seen rapid development over the past decade. This review aims to discuss the state of the technology and to help clarify its role in the diagnosis and management of coronary artery disease. This article highlights major historic perspectives, the accuracy of coronary computed tomography angiography in evaluating obstructive coronary artery disease, associated radiation exposure issues, considerations in patient selection, and ongoing clinical and technologic advancements., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Computed tomography perfusion (CTP) is an emerging method which, coupled with the anatomical detail afforded by cardiac computed tomographic angiography (CCTA), may allow for determination of both structural and physiologic significance of coronary stenoses with a single imaging modality. This study was designed to execute a systematic review/meta-analysis to determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTP as compared with reference standards for detection of significant coronary artery stenoses and impaired perfusion., Methods: A systematic review identified 13 out of 4368 studies allowing a calculation of sensitivity, specificity, PPV, and NPV on a per patient or per vessel or per segment basis using radionuclide myocardial perfusion imaging (MPI), conventional coronary angiography (CCA), magnetic resonance perfusion imaging (MRPI), or fractional flow reserve (FFR) as the reference standard. Meta-analyses of results were carried out using random effects modelling., Results: Most studies used a maximal vasodilator stress protocol with adenosine, provided information mainly on a per vessel basis, and used myocardial perfusion imaging or CCA as the reference standard. Of the studies comparing combinations of both anatomical and functional imaging, the most rigourous standard was CCA/FFR. Compared with the latter, CCTA/CTP had sensitivity, specificity, PPV, and NPV of 81%, 93%, 87%, and 88%, respectively., Conclusions: CTP shows promise as an adjunct to CCTA, potentially allowing determination of both structural and physiologic significance with a single imaging modality., (Copyright © 2012 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The volume of cardiac diagnostic tests that are performed has increased significantly in recent years. The benefits of these tests should be weighed against the risks, including exposure to ionizing radiation. We sought to determine the effective radiation doses associated with common cardiac imaging studies performed at a provincial referral heart centre in Vancouver, Canada, between January 1, 2009 and December 31, 2009., Methods: Effective radiation dose was calculated for all patients who underwent clinically indicated cardiac computed tomography angiography (CCTA), myocardial perfusion imaging (MPI), and diagnostic catheter coronary angiography (CCA) in 2009. The dose from CCTA and CCA studies was estimated from dose-length product and dose area product values, respectively. A conversion factor of 0.014 mSv/(mGy × cm) was used for CCTA and MPI CT attenuation correction. The conversion factor for CCA was 0.22 mSv/(Gy × cm(2)). The effective radiation dose for MPI was calculated using: E = (E/A) × A(o) where E = effective dose, E/A is an effective dose coefficient, and A(o) is the radiotracer activity., Results: There were 673 CCTA studies and 2306 MPI studies performed with average effective doses of 3.7 mSv and 16.8 mSv, respectively. There were 2628 diagnostic CCA studies performed with an average effective dose of 11.4 mSv., Conclusions: There was a wide range of effective radiation doses between imaging modalities. These tests provide different clinical information and the appropriate test must be chosen with radiation dose in mind. The implementation of dose reduction strategies has the potential to significantly reduce these doses., (Copyright © 2011 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Numerous radiation dose reduction measures have been proposed for coronary computed tomographic angiography (CCTA). Although these techniques allow for imaging with reduced radiation, it is unknown whether diagnostic performance is maintained. A new high-definition CCTA (HD-CCTA) allows higher spatial resolution, reduced image noise, and lower radiation doses., Objectives: The aim of this study was to determine the diagnostic performance of HD-CCTA, in combination with multiple radiation dose reduction strategies, for the detection of obstructive coronary artery disease., Methods: Consecutive patients (N = 43, aged 60 ± 10 years, 83% male) with chest pain and referred for quantitative coronary angiography (QCA) underwent HD-CCTA with radiation dose reduction measures, including prospective electrocardiographic triggering, reduction of additional tube on-time, and minimization of tube voltage and current. Intraluminal diameter stenosis ≥ 50% was considered significant. QCA served as the reference standard. The area under the receiver-operating-characteristic curve (AUC) was used to evaluate diagnostic accuracy., Results: All scans demonstrated diagnostic image quality, with 99% (543/548) of included coronary segments interpretable by HD-CCTA. Median effective radiation dose was 2.8 mSv (interquartile range, 1.3-3.9). The AUC for the per-patient assessment for stenosis ≥ 50% was 0.90 (95% confidence interval [CI], 0.77-0.96), with sensitivity of 95% (95% CI, 85%-100%), specificity of 79% (95% CI, 63%-95%), positive predictive value of 78% (95% CI, 61%-95%), and negative predictive value of 95% (95% CI, 85%-100%)., Conclusions: Compared with QCA, HD-CCTA with multiple dose reduction measures resulted in low radiation doses and high diagnostic accuracy to detect and exclude obstructive coronary artery disease., (Copyright © 2011 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)