Clinical Practice Variations in the Management of Ischemia With No Obstructive Coronary Artery Disease.

Background Ischemia with no obstructive coronary artery disease is a condition associated with major adverse cardiovascular outcomes. To date, there are no specific American Heart Association or American College of Cardiology guidelines. The objective of this survey is to better understand the clinical practice and knowledge gaps that exist nationally. Methods and Results Participant-specific links for a survey with 11 questions and 3 reminders were sent between September and October 2020 to the American College of Cardiology CardioSurve Panel. The panel consist of randomly selected cardiologists (n=437) who represent the current profile of the American College of Cardiology US membership. The survey received a 30% response rate. Of the 172 respondents, 130 (76%) indicated that they have treated patients with ischemia with no obstructive coronary artery disease. Although the majority (69%) are generally confident in their ability to manage this condition, 1 of 3 report lack of confidence or are neutral. The American College of Cardiology/American Heart Association Chronic Stable Angina Guidelines are the most commonly used reference for treating ischemia with no obstructive coronary artery disease (81%), with most cardiologists wanting additional clinical guidance, such as randomized controlled trials (61%). More than 4 of 5 cardiologists rarely or never order advanced imaging modalities to assess coronary flow reserve. Approximately 2 of 3 of respondents frequently prescribe statins (68%), aspirin (66%), calcium channel blockers (63%), and ß blockers or α/ß blockers (55%). However, nearly 70% never prescribe angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Conclusions This survey demonstrates heterogeneity in the management of ischemia with no obstructive coronary artery disease among US cardiologists, identifies support for guideline development, and outlines knowledge gaps for research and education in the therapeutic management of this condition.

Normal sex and age-specific parameters in a multi-ethnic population: a cardiovascular magnetic resonance study of the Canadian Alliance for Healthy Hearts and Minds cohort.

BACKGROUND: Despite the growing utility of cardiovascular magnetic resonance (CMR) for cardiac morphology and function, sex and age-specific normal reference values derived from large, multi-ethnic data sets are lacking. Furthermore, most available studies use a simplified tracing methodology. Using a large cohort of participants without history of cardiovascular disease (CVD) or risk factors from the Canadian Alliance for Healthy Heart and Minds, we sought to establish a robust set of reference values for ventricular and atrial parameters using an anatomically correct contouring method, and to determine the influence of age and sex on ventricular parameters. METHODS AND RESULTS: Participants (n = 3206, 65% females; age 55.2 ± 8.4 years for females and 55.1 ± 8.8 years for men) underwent CMR using standard methods for quantitative measurements of cardiac parameters. Normal ventricular and atrial reference values are provided: (1) for males and females, (2) stratified by four age categories, and (3) for different races/ethnicities. Values are reported as absolute, indexed to body surface area, or height. Ventricular volumes and mass were significantly larger for males than females (p < 0.001). Ventricular ejection fraction was significantly diminished in males as compared to females (p < 0.001). Indexed left ventricular (LV) end-systolic, end-diastolic volumes, mass and right ventricular (RV) parameters significantly decreased as age increased for both sexes (p < 0.001). For females, but not men, mean LV and RVEF significantly increased with age (p < 0.001). CONCLUSION: Using anatomically correct contouring methodology, we provide accurate sex and age-specific normal reference values for CMR parameters derived from the largest, multi-ethnic population free of CVD to date. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02220582. Registered 20 August 2014-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02220582 .

The impact of reporting magnetic resonance imaging incidental findings in the Canadian alliance for healthy hearts and minds cohort.

BACKGROUND: In the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort, participants underwent magnetic resonance imaging (MRI) of the brain, heart, and abdomen, that generated incidental findings (IFs). The approach to managing these unexpected results remain a complex issue. Our objectives were to describe the CAHHM policy for the management of IFs, to understand the impact of disclosing IFs to healthy research participants, and to reflect on the ethical obligations of researchers in future MRI studies. METHODS: Between 2013 and 2019, 8252 participants (mean age 58 ± 9 years, 54% women) were recruited with a follow-up questionnaire administered to 909 participants (40% response rate) at 1-year. The CAHHM policy followed a restricted approach, whereby routine feedback on IFs was not provided. Only IFs of severe structural abnormalities were reported. RESULTS: Severe structural abnormalities occurred in 8.3% (95% confidence interval 7.7-8.9%) of participants, with the highest proportions found in the brain (4.2%) and abdomen (3.1%). The majority of participants (97%) informed of an IF reported no change in quality of life, with 3% of participants reporting that the knowledge of an IF negatively impacted their quality of life. Furthermore, 50% reported increased stress in learning about an IF, and in 95%, the discovery of an IF did not adversely impact his/her life insurance policy. Most participants (90%) would enrol in the study again and perceived the MRI scan to be beneficial, regardless of whether they were informed of IFs. While the implications of a restricted approach to IF management was perceived to be mostly positive, a degree of diagnostic misconception was present amongst participants, indicating the importance of a more thorough consent process to support participant autonomy. CONCLUSION: The management of IFs from research MRI scans remain a challenging issue, as participants may experience stress and a reduced quality of life when IFs are disclosed. The restricted approach to IF management in CAHHM demonstrated a fair fulfillment of the overarching ethical principles of respect for autonomy, concern for wellbeing, and justice. The approach outlined in the CAHHM policy may serve as a framework for future research studies. Clinical trial registration https://clinicaltrials.gov/ct2/show/NCT02220582 .

Clinical Practice Variations in the Management of Stress-Induced Cardiomyopathy: A Canadian Perspective.

Despite increased recognition of stress-induced cardiomyopathy (SIC), there are no randomized controlled trials or established guidelines to direct therapeutic strategies and little is known about the local experience in Canada. The objective of this study was to better understand the clinical practice variations in the management of SIC across Canada. By using an online platform, a series of questions were distributed to practicing cardiologists between October and November 2018. In total, 172 cardiologists completed the survey. Although many cardiologists have managed patients with SIC, more than two-thirds do not adhere to any guidelines or references. Of those who do, the top referenced resources included expert consensus statements from the American College of Cardiology, the European Society of Cardiology, general heart failure guidelines, and UpToDate. Regarding investigations, most participants routinely order TTEs and coronary angiograms, and a minority would order pheochromocytoma workup. Common medications prescribed for hemodynamically stable patients include ß-blockers, angiotensin-converting enzyme inhibitors, antiplatelet agents, and anticoagulation. Some 3% of participants reported not prescribing any cardiac medications. Most respondents follow up with patients with SIC within a 3-month period. The risk factors most believed to be associated with SIC included female gender, anxiety, older age, ethnicity, and diabetes. No participants believed that male gender was a risk factor. Many participants believed there needs to be improvements made, such as a Canadian guideline, a Canadian registry, or dedicated workshops at the national cardiology conference. This study demonstrates ongoing variability in the clinical management of SIC across Canada and illustrates a potential area for further research.

Cardiovascular risk is associated with a transmural gradient of myocardial oxygenation during adenosine infusion.

AIMS: In patients with coronary artery disease (CAD), a transmural gradient of myocardial perfusion has been repeatedly observed, with the subendocardial layer showing more pronounced perfusion deficits. Oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) allows for monitoring transmural changes of myocardial oxygenation in vivo. We hypothesized that OS-CMR could help identify a transmural oxygenation gradient as a disease marker in patients at risk for CAD. METHODS AND RESULTS: We assessed 34 patients with known CAD and 28 subjects with coronary risk factors but no evidence of significant CAD. Results were compared with 11 healthy volunteers. OS-CMR was performed at 1.5 T, applying a T2*-weighted cine steady state free precession sequence at baseline and during infusion of adenosine. A reader blinded to patient data quantified the relative change of myocardial oxygenation in OS-CMR, defined by the change of signal intensity (ΔSI%) between baseline and during adenosine infusion in the entire myocardium, the subepicardial layer, and the subendocardial layer. SI changes were homogenous throughout the myocardium in healthy subjects, whereas both, patients with risk factors only and patients with CAD, had a significantly smaller ΔSI% in the subendocardial layer than in the subendocardial layer. Both patient groups had an overall decreased ΔSI% across all layers when compared with healthy subjects (P < 0.05). CONCLUSION: Even in the absence of overt CAD, cardiovascular risk factors are associated with a transmural gradient of the myocardial oxygenation response to adenosine as assessed by OS-CMR. An inducible transmural oxygenation gradient may serve as a non-invasive marker for cardiovascular risk.

Relationship of vasodilator-induced changes in myocardial oxygenation with the severity of coronary artery stenosis: a study using oxygenation-sensitive cardiovascular magnetic resonance.

AIMS: To explore the impact of the functional severity of coronary artery stenosis on changes in myocardial oxygenation during pharmacological vasodilation, using oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) imaging and invasive fractional flow reserve (FFR). An FFR is considered a standard of reference for assessing haemodynamic relevance of coronary artery stenosis; yet, the relationship of FFR to changes in myocardial oxygenation during vasodilator stress and thus to an objective marker for ischaemia on the tissue level is not well understood. METHODS AND RESULTS: We prospectively recruited 64 patients with suspected/known coronary artery disease undergoing invasive angiography. The FFR was performed in intermediate coronary artery stenosis. OS-CMR images were acquired using a T2*-sensitive sequence before and after adenosine-induced vasodilation, with myocardial segments matched to angiography. Very strict image quality criteria were defined to ensure the validity of results. The FFR was performed in 37 patients. Because of the strict image quality criteria, 41% of segments had to be excluded, leaving 29/64 patients for the blinded OS-CMR analysis. Coronary territories with an associated FFR of <0.80 showed a lack of increase in myocardial oxygenation [mean signal intensity (ΔSI) -0.49%; 95% confidence interval (CI) -3.78 to 2.78 vs. +7.30%; 95% CI 4.08 to 10.64; P < 0.001]. An FFR of <0.54 best predicted a complete lack of a vasodilator-induced oxygenation increase (sensitivity 71% and specificity 75%). An OS-CMR ΔSI <4.78% identified an FFR of <0.8 with a sensitivity of 86% and specificity of 92%. CONCLUSION: An FFR of <0.80 is associated with a lack of an adenosine-inducible increase in oxygenation of the dependent coronary territory, while a complete lack of such an increase was best predicted by an FFR of <0.54. Further studies are warranted to identify clinically meaningful cut-off values for FFR measurements and to assess the utility of OS-CMR as an alternative clinical tool for assessing the functional relevance of coronary artery stenosis.

Indications, safety and image quality of cardiovascular magnetic resonance: experience in >5,000 North American patients.

BACKGROUND: CMR offers accurate assessment of structure and function with high resolution. Although the use of CMR has been well established in Europe, information is lacking for the extent of this emerging modality in North America. OBJECTIVES: This study aimed to summarize indications, safety, image quality, extent of contrast use and extent of stress tests performed in a high-volume CMR centre. METHODS: Consecutive patients scanned from July 2005 to November 2010 were included, with duplicates and research subjects removed. Original clinical referrals were categorized into 10 main indications. RESULTS: Retrospective analysis was performed on 6463 patients (mean±SD age=50±17). The most common clinical indications were non-ischemic cardiomyopathies (28%), including myocarditis (18%), coronary artery disease (17%), ARVD and/or other RV disease (12%), and congenital heart disease (11%). Gadolinium-based contrast was given to 89.5% of patients as part of their CMR protocol. Of 10.9% (703/6463) of patients that underwent stress CMR, adenosine was administered most commonly. Of 703 patients, 1 (0.14%) suffered ventricular tachycardia during adenosine stress, and transient, asymptomatic AV block was occasionally observed. Moderate to severe complications after contrast agent administration occurred in 9 (0.16%) of 5782 contrast-enhanced studies, characterized by nausea and vomiting in 6 (0.12%) and by symptoms of acute systemic allergic reaction in 2 (0.04%). Image quality was good (82.0%), moderate but diagnostic (16.6%) and poor in 1.4% of cases. CONCLUSION: In the high-volume CMR centre, main clinical indications were for myocarditis/cardiomyopathies, coronary artery disease and RV-related queries. CMR showed an excellent safety profile and high image quality in 99% of cases.