Jennifer Bryant

Higher Oily Fish Consumption in Late Pregnancy is Associated With Reduced Aortic Stiffness in the Child at Age 9 Years

RATIONALE Higher pulse wave velocity (PWV) reflects increased arterial stiffness and is an established cardiovascular risk marker associated with lower long-chain n-3 polyunsaturated fatty acid intake in adults. Experimentally, maternal fatty acid intake in pregnancy has lasting effects on offspring arterial stiffness. OBJECTIVE To examine the association between maternal consumption of oily fish, a source of long-chain n-3 polyunsaturated fatty acids, in pregnancy and childs aortic stiffness age 9 years. METHODS AND RESULTS In a mother-offspring study (Southampton Womens Survey), the childs descending aorta PWV was measured at the age of 9 years using velocity-encoded phase-contrast MRI and related to maternal oily fish consumption assessed prospectively during pregnancy. Higher oily fish consumption in late pregnancy was associated with lower childhood aortic PWV (sex-adjusted β=-0.084 m/s per portion per week; 95% confidence interval, -0.137 to -0.031; P=0.002; n=226). Mothers educational attainment was independently associated with childs PWV. PWV was not associated with the childs current oily fish consumption. CONCLUSIONS Level of maternal oily fish consumption in pregnancy may influence childs large artery development, with potential long-term consequences for later cardiovascular risk.

Assessing exercise cardiac reserve using real-time cardiovascular magnetic resonance

BackgroundExercise cardiovascular magnetic resonance (ExCMR) has great potential for clinical use but its development has been limited by a lack of compatible equipment and robust real-time imaging techniques. We developed an exCMR protocol using an in-scanner cycle ergometer and assessed its performance in differentiating athletes from non-athletes.MethodsFree-breathing real-time CMR (1.5T Aera, Siemens) was performed in 11 athletes (5 males; median age 29 [IQR: 28–39] years) and 16 age- and sex-matched healthy volunteers (7 males; median age 26 [interquartile range (IQR): 25–33] years). All participants underwent an in-scanner exercise protocol on a CMR compatible cycle ergometer (Lode BV, the Netherlands), with an initial workload of 25W followed by 25W-increment every minute. In 20 individuals, exercise capacity was also evaluated by cardiopulmonary exercise test (CPET). Scan-rescan reproducibility was assessed in 10 individuals, at least 7 days apart.ResultsThe exCMR protocol demonstrated excellent scan-rescan (cardiac index (CI): 0.2 ± 0.5L/min/m2) and inter-observer (ventricular volumes: 1.2 ± 5.3mL) reproducibility. CI derived from exCMR and CPET had excellent correlation (r = 0.83, p < 0.001) and agreement (1.7 ± 1.8L/min/m2). Despite similar values at rest (P = 0.87), athletes had increased exercise CI compared to healthy individuals (at peak exercise: 12.2 [IQR: 10.2–13.5] L/min/m2 versus 8.9 [IQR: 7.5–10.1] L/min/m2, respectively; P < 0.001). Peak exercise CI, where image acquisition lasted 13–17 s, outperformed that at rest (c-statistics = 0.95 [95% confidence interval: 0.87–1.00] versus 0.48 [95% confidence interval: 0.23–0.72], respectively; P < 0.0001 for comparison) in differentiating athletes from healthy volunteers; and had similar performance as VO2max (c-statistics = 0.84 [95% confidence interval = 0.62–1.00]; P = 0.29 for comparison).ConclusionsWe have developed a novel in-scanner exCMR protocol using real-time CMR that is highly reproducible. It may now be developed for clinical use for physiological studies of the heart and circulation.

Novel Index of Maladaptive Myocardial Remodeling in HypertensionCLINICAL PERSPECTIVE

Background— Hypertensive left ventricular hypertrophy (HTN-LVH) is a leading cause of heart failure. Conventional patterns of cardiac geometry do not adequately risk-stratify patients with HTN-LVH. Using cardiovascular magnetic resonance, we developed a novel Remodeling Index (RI) that was designed to detect an exaggerated hypertrophic response to hypertension and tested its potential to risk-stratify hypertensive patients. Methods and Results— The RI was derived using LaPlace’s Law ( ), and normal RI ranges were established in 180 healthy volunteers. The utility of the RI was examined in 256 asymptomatic hypertensive patients and 10 patients with heart failure with preserved ejection fraction. Hypertensive patients underwent multimodal cardiac assessment: contrast-enhanced cardiovascular magnetic resonance, echocardiograms, 24-hour blood pressure monitoring, and cardiac biomarkers (high-sensitivity cardiac troponins, NT-proBNP [N-terminal pro-B-type natriuretic peptide], and galectin-3). Blood pressure accounted for only 20% of the variance observed in LV mass. Although there was no association between blood pressure and myocardial fibrosis, LV mass was independently associated with fibrosis. Compared with hypertensive patients without LVH (n=191; 74.6%) and those with HTN-LVH and normal RI (n=50; 19.5%), patients with HTN-LVH and low RI (HTN-LVH/low RI; n=15, 5.9%) had an amplified myocardial response: elevated indexed LV masses (83±24 g/m2), more fibrosis (73%), and higher biomarkers of myocardial injury and dysfunction (P<0.05 for all). RI was similar in HTN-LVH/low RI and heart failure with preserved ejection fraction (4.1 [3.4–4.5] versus 3.7 [3.4–4.0], respectively; P=0.15). Conclusions— We suggest that RI provides an approach for stratifying hypertensive patients and is suitable for testing in other disease cohorts to assess its clinical utility. Clinical Trial Registration— URL: https://clinicaltrials.gov. Unique identifier: NCT02670031.

Stress cardiovascular magnetic resonance imaging: current and future perspectives

ABSTRACT Introduction: Vasodilator and dobutamine are the main pharmacological agents used in current stress cardiovascular magnetic resonance (CMR). Exercise stress has well-established advantages and it is commonly used in other stress imaging, but the technical considerations have limited its use in stress CMR. In this review, we will describe the diagnostic performance, prognostic value, strengths and challenges of current stress CMR techniques. We will also discuss future perspectives of exercise stress CMR. Areas covered: Despite notable mechanistic differences, vasodilator and dobutamine stress CMR offer similar diagnostic and prognostic value in coronary artery disease. Combined perfusion and wall motion assessment has been explored with dobutamine stress CMR: diagnostic sensitivity improved at the expense of reduced specificity. However, a combined assessment may provide additional prognostic value in selected patients. There is emerging interest and promising data in exercise stress CMR because of the availability of CMR-compatible stress equipment and development of novel real-time sequences that allow imaging during exercise with adequate spatiotemporal resolution. Expert commentary: Exercise stress CMR is able to assess wall motion abnormalities, perfusion defects, exercise capacity and viability in a single examination. This holds important clinical potential in a variety of cardiovascular conditions.

Early clinical experience with ‘splenic switch-off' in adenosine stress CMR

Background MRI Adenosine stress perfusion is a well-established method of evaluating myocardial ischaemia but we know from a number of studies that false negatives are a potential weakness of this modality. Assessment of splenic perfusion at stress and rest (splenic switch-off) has recently been suggested as a means of identifying true pharmacological stress response to adenosine [1]. This is a promising technique but can only be assessed after the stress procedure. The aim of this study was to compare symptomatic and haemodynamic response with visual assessment of splenic perfusion during stress and rest perfusion imaging to see if we could accurately predict those who would have absent splenic switch-off.

Turning up the adenosine turns off the spleen

Background Adenosine as a stress agent is well tolerated and has a good safety profile but occasionally when administered at 140mg/kg/min it fails to produce a haemodynamic or symptomatic response. Studies have reported that between 4 18% patients do not respond to the standard dose . Splenic switch-off is a novel way of assessing adequacy of hyperaemic response, to adenosine. The aim of this study was to assess the number of patients that required an increase in dose to either 175 mg/kg/min or 210 mg/kg/min over a 12-month period and the adequacy of this response using splenic switch-off.

Magnetic resonance imaging of pulse wave velocity in children aged 9 years to assess maternal influences on aortic stiffness in the offspring

Background Pulse wave velocity (PWV) is an indirect measure of vascular stiffness. Higher PWV is a recognised cardiovascular risk marker. Magnetic resonance imaging (MRI) is a non-invasive method of assessing PWV. Assessing maternal influences on offspring PWV is important as reduced fetal nutrient supply and impaired early development are linked with an increased risk of cardiovascular disease in adulthood. In multiparous women, changes in the uterine spiral arteries arising during previous pregnancies result in increased fetal nutrient supply. Rat studies have shown that changes in maternal fatty acid intake in pregnancy are associated with increased offspring arterial stiffness. Some studies of human adults suggest omega-3 fish oils reduce arterial stiffness. The objective of the study was to measure vascular stiffness using MRI, and examine maternal influences on vascular structure in children aged 9 years.

Cardiovascular magnetic resonance: interstudy reproducibility of measurements of left ventricular function in children.

In adults CMR is the gold standard technique for evaluation of LV function, with reportedly excellent interstudy reproducibility. In children compliance with breath-hold instructions and motion control can be significantly reduced and there is limited data on CMR reproducibility.

T1 mapping across the ejection fraction spectrum

Methods 242 consecutive consenting patients referred for CMR between December 2014 and June 2015 were scanned on a 1.5T Magnetom Avanto (Siemens Healthcare, Erlangen) using a MOLLI (WIP#448, 5:3:3 acquisition scheme, motion correction and automatically generated T1 map). In all cases on the basal short axis slice, a single, slender ROI was placed in the mid wall of the septum with meticulous attention to avoid partial volume of blood/and or scar areas to derive the native T1 in msec. The patients were grouped by ejection fraction: 55%. 15 healthy volunteers were also used as a control group. Ejection fraction (EF), LV volumes, LV mass and BSA indexed left atrial area (LAAi) were also acquired. Comparison was performed using ANOVA and linear regression with adjustment for demographic variables that were found to vary between groups (age and BSAi LV mass).

Insights from T1 mapping in heart failure

Methods Sixteen healthy subjects and 35 patients with heart failure awaiting guideline indicated CRT or primary prevention ICD (16 non ischemic cardiomyopathy (NICM), 19 ischemic cardiomyopathy (ICM)) were scanned on a 1.5T Magnetom Avanto (Siemens Healthcare, Erlangen) using a MOLLI (investigational WIP#448, 5:3:3 acquisition scheme, motion correction and automatically generated T1 map). In all cases on the basal short axis slice, a single, slender ROI was placed in the mid wall of the septum with meticulous attention to avoid partial volume of blood. In addition, the T1 was measured within scar when present on the T1 map (confirmed on the corresponding basal LGE image). When a contemporaneous haematocrit was available (n=24), the extracellular volume (ECV) was calculated using standard bolus acquisition methods.