Acceptability and feasibility of magnetic femoral nerve stimulation in older, functionally impaired patients

Objective

Magnetic femoral nerve stimulation to test muscle function has been largely unexplored in older people. We assessed acceptability, feasibility, along with reproducibility and correlation with other physical function measures.

Results

Study 1 recruited older people with sarcopenia. Stimulation was performed at baseline and 2 weeks along with six minute walk (6MW), maximum voluntary quadriceps contraction, short physical performance battery and grip strength. Acceptability was measured using visual analog scales. Study 2 used baseline data from a trial of older people. We correlated stimulation results with 6MW, maximal voluntary contraction and muscle mass. Maximum quadriceps twitch tension was measured in both studies, evoked using biphasic magnetic stimulation of the femoral nerve. In study 1 (n = 12), magnetic stimulation was well tolerated with mean discomfort rating of 9% (range 0–40%) on a visual analog scale. Reproducibility was poor (intraclass correlation coefficient 0.06; p = 0.44). Study 2 (n = 64) showed only weak to moderate correlations for maximum quadriceps twitch tension with other measures of physical function (6 minute walk test r = 0.24, p = 0.06; maximal voluntary contraction r = 0.26; p = 0.04). We conclude that magnetic femoral nerve stimulation is acceptable and feasible but poorly reproducible in older, functionally impaired people.

Prevalence and Distribution of Atherosclerosis in a Low- to Intermediate-Risk Population: Assessment with Whole-Body MR Angiography

Purpose To quantify the burden and distribution of asymptomatic atherosclerosis in a population with a low to intermediate risk of cardiovascular disease. Materials and Methods Between June 2008 and February 2013, 1528 participants with 10-year risk of cardiovascular disease less than 20% were prospectively enrolled. They underwent whole-body magnetic resonance (MR) angiography at 3.0 T by using a two-injection, four-station acquisition technique. Thirty-one arterial segments were scored according to maximum stenosis. Scores were summed and normalized for the number of assessable arterial segments to provide a standardized atheroma score (SAS). Multiple linear regression was performed to assess effects of risk factors on atheroma burden. Results A total of 1513 participants (577 [37.9%] men; median age, 53.5 years; range, 40-83 years) completed the study protocol. Among 46 903 potentially analyzable segments, 46 601 (99.4%) were interpretable. Among these, 2468 segments (5%) demonstrated stenoses, of which 1649 (3.5%) showed stenosis less than 50% and 484 (1.0%) showed stenosis greater than or equal to 50%. Vascular stenoses were distributed throughout the body with no localized distribution. Seven hundred forty-seven (49.4%) participants had at least one stenotic vessel, and 408 (27.0%) participants had multiple stenotic vessels. At multivariable linear regression, SAS correlated with age (B = 3.4; 95% confidence interval: 2.61, 4.20), heart rate (B = 1.23; 95% confidence interval: 0.51, 1.95), systolic blood pressure (B = 0.02; 95% confidence interval: 0.01, 0.03), smoking status (B = 0.79; 95% confidence interval: 0.44, 1.15), and socioeconomic status (B = -0.06; 95% confidence interval: -0.10, -0.02) (P < .01 for all). Conclusion Whole-body MR angiography identifies early vascular disease at a population level. Although disease prevalence is low on a per-vessel level, vascular disease is common on a per-participant level, even in this low- to intermediate-risk cohort. © RSNA, 2018 Online supplemental material is available for this article.

Effect of Vitamin D Supplementation on Markers of Vascular Function: A Systematic Review and Individual Participant Meta-Analysis

Background

Low 25‐hydroxyvitamin D levels are associated with an increased risk of cardiovascular events, but the effect of vitamin D supplementation on markers of vascular function associated with major adverse cardiovascular events is unclear.

Methods and Results

We conducted a systematic review and individual participant meta‐analysis to examine the effect of vitamin D supplementation on flow‐mediated dilatation of the brachial artery, pulse wave velocity, augmentation index, central blood pressure, microvascular function, and reactive hyperemia index. MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and http://www.ClinicalTrials.gov were searched until the end of 2016 without language restrictions. Placebo‐controlled randomized trials of at least 4 weeks duration were included. Individual participant data were sought from investigators on included trials. Trial‐level meta‐analysis was performed using random‐effects models; individual participant meta‐analyses used a 2‐stage analytic strategy, examining effects in prespecified subgroups. 31 trials (2751 participants) were included; 29 trials (2641 participants) contributed data to trial‐level meta‐analysis, and 24 trials (2051 participants) contributed to individual‐participant analyses. Vitamin D3 daily dose equivalents ranged from 900 to 5000 IU; duration was 4 weeks to 12 months. Trial‐level meta‐analysis showed no significant effect of supplementation on macrovascular measures (flow‐mediated dilatation, 0.37% [95% confidence interval, −0.23 to 0.97]; carotid‐femoral pulse wave velocity, 0.00 m/s [95% confidence interval, −0.36 to 0.37]); similar results were obtained from individual participant data. Microvascular function showed a modest improvement in trial‐level data only. No consistent benefit was observed in subgroup analyses or between different vitamin D analogues.

Conclusions

Vitamin D supplementation had no significant effect on most markers of vascular function in this analysis.

Disconnection of pulmonary and systemic arterial stiffness in COPD

Background

Both pulmonary arterial stiffening and systemic arterial stiffening have been described in COPD. The aim of the current study was to assess pulse wave velocity (PWV) within these two arterial beds to determine whether they are separate or linked processes.

Materials and methods

In total, 58 participants with COPD and 21 healthy volunteers (HVs) underwent cardiac magnetic resonance imaging (MRI) and were tested with a panel of relevant biomarkers. Cardiac MRI was used to quantify ventricular mass, volumes, and pulmonary (pulse wave velocity [pPWV] and systemic pulse wave velocity [sPWV]).

Results

Those with COPD had higher pPWV (COPD: 2.62 vs HV: 1.78 ms⁻¹, p=0.006), higher right ventricular mass/volume ratio (RVMVR; COPD: 0.29 vs HV: 0.25 g/mL, p=0.012), higher left ventricular mass/volume ratio (LVMVR; COPD: 0.78 vs HV: 0.70 g/mL, p=0.009), and a trend toward a higher sPWV (COPD: 8.7 vs HV: 7.4 ms⁻¹, p=0.06). Multiple biomarkers were elevated: interleukin-6 (COPD: 1.38 vs HV: 0.58 pg/mL, p=0.02), high-sensitivity C-reactive protein (COPD: 6.42 vs HV: 2.49 mg/L, p=0.002), surfactant protein D (COPD: 16.9 vs HV: 9.13 ng/mL, p=0.001), N-terminal pro-brain natriuretic peptide (COPD: 603 vs HV: 198 pg/mL, p=0.001), and high-sensitivity troponin I (COPD: 2.27 vs HV: 0.92 pg/mL, p<0.001). There was a significant relationship between sPWV and LVMVR (p=0.01) but not pPWV (p=0.97) nor between pPWV and RVMVR (p=0.27).

Conclusion

Pulmonary arterial stiffening and systemic arterial stiffening appear to be disconnected and should therefore be considered independent processes in COPD. Further work is warranted to determine whether both these cause an increased morbidity and mortality and whether both can be targeted by similar pharmacological therapy or whether different strategies are required for each.

Development and Validation of a Path Length Calculation for Carotid-Femoral Pulse Wave Velocity Measurement: A TASCFORCE, SUMMIT, and Caerphilly Collaborative Venture

Supplemental Digital Content is available in the text.

Current distance measurement techniques for pulse wave velocity (PWV) calculation are susceptible to intercenter variability. The aim of this study was to derive and validate a formula for this distance measurement. Based on carotid femoral distance in 1183 whole-body magnetic resonance angiograms, a formula was derived for calculating distance. This was compared with distance measurements in 128 whole-body magnetic resonance angiograms from a second study. The effects of recalculation of PWV using the new formula on association with risk factors, disease discrimination, and prediction of major adverse cardiovascular events were examined within 1242 participants from the multicenter SUMMIT study (Surrogate Markers of Micro- and Macrovascular Hard End-Points for Innovative Diabetes Tools) and 825 participants from the Caerphilly Prospective Study. The distance formula yielded a mean error of 7.8 mm (limits of agreement =−41.1 to 56.7 mm; P<0.001) compared with the second whole-body magnetic resonance angiogram group. Compared with an external distance measurement, the distance formula did not change associations between PWV and age, blood pressure, or creatinine (P<0.01) but did remove significant associations between PWV and body mass index (BMI). After accounting for differences in age, sex, and mean arterial pressure, intercenter differences in PWV persisted using the external distance measurement (F=4.6; P=0.004), whereas there was a loss of between center difference using the distance formula (F=1.4; P=0.24). PWV odds ratios for cardiovascular mortality remained the same using both the external distance measurement (1.14; 95% confidence interval, 1.06–1.24; P=0.001) and the distance formula (1.17; 95% confidence interval, 1.08–1.28; P<0.001). A population-derived automatic distance calculation for PWV obtained from routinely collected clinical information is accurate and removes intercenter measurement variability without impacting the diagnostic utility of carotid–femoral PWV.

Pulmonary arterial stiffening in COPD and its implications for right ventricular remodelling

Background

Pulmonary pulse wave velocity (PWV) allows the non-invasive measurement of pulmonary arterial stiffening, but has not previously been assessed in COPD. The aim of the current study was to assess PWV in COPD and its association with right ventricular (RV) remodelling.

Methods

Fifty-eight participants with COPD underwent pulmonary function tests, 6-min walk test and cardiac MRI, while 21 healthy controls (HCs) underwent cardiac MRI. Thirty-two COPD patients underwent a follow-up MRI to assess for longitudinal changes in RV metrics. Cardiac MRI was used to quantify RV mass, volumes and PWV. Differences in continuous variables between the COPD and HC groups was tested using an independent t-test, and associations between PWV and right ventricular parameters was examined using Pearson’s correlation coefficient.

Results

Those with COPD had reduced pulsatility (COPD (mean±SD):24.88±8.84% vs. HC:30.55±11.28%, p=0.021), pulmonary acceleration time (COPD:104.0±22.9ms vs. HC: 128.1±32.2ms, p<0.001), higher PWV (COPD:2.62±1.29ms^-1 vs. HC:1.78±0.72ms^-1, p=0.001), lower RV end diastolic volume (COPD:53.6±11.1ml vs. HC:59.9±13.0ml, p=0.037) and RV stroke volume (COPD:31.9±6.9ml/m² vs. HC:37.1±6.2ml/m², p=0.003) with no difference in mass (p=0.53). PWV was not associated with right ventricular parameters.

Conclusions

While pulmonary vascular remodelling is present in COPD, cardiac remodelling favours reduced filling rather than increased afterload. Treatment of obstructive lung disease may have greater effect on cardiac function than treatment of pulmonary vascular disease in most COPD patients

Key Points

• Pulmonary pulse wave velocity (PWV) is elevated in COPD.

• Pulmonary PWV is not associated with right ventricular remodelling.

• Right ventricular remodelling is more in keeping with that of reduced filling.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5346-x) contains supplementary material, which is available to authorized users.

Systemic arteriosclerosis is associated with left ventricular remodeling but not atherosclerosis: a TASCFORCE study

BACKGROUND

Arteriosclerosis (arterial stiffening) is associated with future cardiovascular events, with this effect postulated to be due to its effect on cardiac afterload, atherosclerosis (plaque formation) progression or both, but with limited evidence examining these early in disease formation. The aim of the current study is to examine the association between arteriosclerosis, atherosclerosis and ventricular remodelling in a population at low-intermediate cardiovascular risk.

METHODS

One thousand six hundred fifty-one subjects free of clinical cardiovascular disease and with a < 20% 10 year cardiovascular risk score underwent a cardiovascular magnetic resonance (CMR) study and whole body CMR angiogram. Arteriosclerosis was measured using total arterial compliance (TAC) - calculated as the indexed stroke volume divided by the pulse pressure. Atherosclerosis was quantified using a standardised atheroma score (SAS) which was calculated by scoring 30 arterial segments within the body based on the degree of stenosis, summating these scores and normalising it to the number of assessable segments. Left ventricular remodelling was measured using left ventricular mass to volume ratio (LVMVR).

RESULTS

One thousand five hundred fifteen (38% male, 53.8 ± 8.2 years old) completed the study. On univariate analysis TAC was associated with SAS but this was lost after accounting for cardiovascular risk factors in both males (B = - 0.001 (- 0.004-0.002),p = 0.62) and females (B = 0.000(95%CI -0.002--0.002),p = 0.78). In contrast compliance correlated with LVMVR after accounting for cardiovascular risk factors (B = - 0.12(95%CI -0.16--0.091),p < 0.001 in males; B = - 0.12(95%CI -0.15--0.086),p < 0.001 in females).

CONCLUSION

Systemic arteriosclerosis is associated with left ventricular remodelling but not atherosclerosis. Future efforts in cardiovascular risk prevention should thus seek to address both arteriosclerosis and atherosclerosis individually.

Effects of contrast administration on cardiac MRI volumetric, flow and pulse wave velocity quantification using manual and software-based analysis

Objective:

The aim of the current study was to determine the effects of gadolinium contrast agent on right (RV) and left ventricular (LV) volumetric, aortic flow and pulse wave velocity (PWV) quantification using manual, semi-automatic and fully automatic analysis techniques.

Methods:

61 participants free from known cardiovascular disease were recruited. Cardiac MR was performed on a 3 T scanner. A balanced steady-state free precession stack was acquired of the ventricles with phase contrast imaging of the aorta performed pre- and post-administration of 10 ml 0.5 mmol ml⁻¹ gadoterate meglumine. The images were analysed manually, and using a semi-automated and a fully automated technique.

Results:

54 completed the study. Gadolinium-based contrast administration significantly increase the signal-to-noise ratio (pre: 830 ± 398 vs post: 1028 ± 540, p = 0.003) with no significant change in contrast-to-noise ratio (pre: 583 ± 302 vs post: 559 ± 346, p = 0.54). On LV analysis, post-contrast analysis yielded significantly higher end systolic volume (54 ± 20 vs 57 ± 18 ml, p = 0.04), and lower ejection fraction (59 ± 9 vs 57 ± 8%, p = 0.023). On RV analysis, gadolinium contrast resulted in no significant differences. Similar results were seen using the semi-automated and fully-automated techniques but with a larger magnitude of difference. Conversely, using both manual and software analysis aortic flow and PWV quantification proved robust to the effects of contrast agent producing only small non-significant differences.

Conclusion:

Gadolinium contrast administration significantly alters LV endocardial contour detection with this effect amplified when using semi-automated analysis techniques. In comparison, RV and PWV analysis is robust to these effects.

Advances in knowledge:

Contrast administration alters LV quantification but not flow analysis. However, these differences are small.

Leucine and ACE inhibitors as therapies for sarcopenia (LACE trial): study protocol for a randomised controlled trial

BACKGROUND

Sarcopenia (the age-related loss of muscle mass and function) is a major contributor to loss of mobility, falls, loss of independence, morbidity and mortality in older people. Although resistance training is effective in preventing and reversing sarcopenia, many older people are sedentary and either cannot or do not want to exercise. This trial examines the efficacy of supplementation with the amino acid leucine and/or angiotensin converting enzyme inhibition to potentially improve muscle mass and function in people with sarcopenia. Promising preliminary data exist from small studies for both interventions, but neither has yet been tested in adequately powered randomised trials in patients with sarcopenia.

METHODS

Leucine and ACE inhibitors in sarcopenia (LACE) is a multicentre, masked, placebo-controlled, 2 × 2 factorial randomised trial evaluating the efficacy of leucine and perindopril (angiotensin converting enzyme inhibitor (ACEi)) in patients with sarcopenia. The trial will recruit 440 patients from primary and secondary care services across the UK. Male and female patients aged 70 years and over with sarcopenia as defined by the European Working Group on Sarcopenia (based on low total skeletal muscle mass on bioimpedance analysis and either low gait speed or low handgrip strength) will be eligible for participation. Participants will be excluded if they have a contraindication to, or are already taking, an ACEi, angiotensin receptor blocker or leucine. The primary clinical outcome for the trial is the between-group difference in the Short Physical Performance Battery score at all points between baseline and 12 months. Secondary outcomes include appendicular muscle mass measured using dual-energy X-ray absorptiometry, muscle strength, activities of daily living, quality of life, activity using pedometer step counts and falls. Participants, clinical teams, outcomes assessors and trial analysts are masked to treatment allocation. A panel of biomarkers including microRNAs, neurohormones, genetic polymorphisms and markers of inflammation relevant to muscle pathophysiology will be measured to explore predictors of response and further elucidate mechanisms underlying sarcopenia. Participants will receive a total of 12 months of either perindopril or placebo and either leucine or placebo.

DISCUSSION

The results will provide the first robust test of the overall clinical and cost-effectiveness of these novel therapies for older patients with sarcopenia.

TRIAL REGISTRATION

ISRCTN, ISRCTN90094835 . Registered on 18 February 2015.

Renal and Cardiovascular Effects of sodium-glucose cotransporter 2 (SGLT2) inhibition in combination with loop Diuretics in diabetic patients with Chronic Heart Failure (RECEDE-CHF): protocol for a randomised controlled double-blind cross-over trial

INTRODUCTION

Type 2 diabetes (T2D) and heart failure (HF) are a frequent combination, where treatment options remain limited. There has been increasing interest around the sodium-glucose cotransporter 2 (SGLT2) inhibitors and their use in patients with HF. Data on the effect of SGLT2 inhibitor use with diuretics are limited. We hypothesise that SGLT2 inhibition may augment the effects of loop diuretics and the benefits of SGLT2 inhibitors may extend beyond those of their metabolic (glycaemic parameters and weight loss) and haemodynamic parameters. The effects of SGLT2 inhibitors as an osmotic diuretic and on natriuresis may underlie the cardiovascular and renal benefits demonstrated in the recent EMPA-REG study.

METHODS AND ANALYSIS

To assess the effect of SGLT2 inhibitors when used in combination with a loop diuretic, the RECEDE-CHF (Renal and Cardiovascular Effects of SGLT2 inhibition in combination with loop Diuretics in diabetic patients with Chronic Heart Failure) trial is a single-centre, randomised, double-blind, placebo-controlled, cross-over trial conducted in a secondary care setting within NHS Tayside, Scotland. 34 eligible participants, aged between 18 and 80 years, with stable T2D and CHF will be recruited. Renal physiological testing will be performed at two points (week 1 and week 6) on each arm to assess the effect of 25 mg empagliflozin, on the primary and secondary outcomes. Participants will be enrolled in the trial for a total period between 14 and 16 weeks. The primary outcome will assess the effect of empagliflozin versus placebo on urine output. The secondary outcomes are to assess the effect of empagliflozin on glomerular filtration rate, cystatin C, urinary sodium excretion, urinary protein/creatinine ratio and urinary albumin/creatinine ratio when compared with placebo.

ETHICS AND DISSEMINATION

Ethics approval was obtained by the East of Scotland Research Ethics Service. Results of the trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT03226457; Pre-results.

Association between GDF-15 levels and changes in vascular and physical function in older patients with hypertension

BACKGROUND

Growth differentiation factor-15 (GDF-15) may be a biomarker of disease, protective response and/or prognosis, in older people with hypertension.

AIMS

To correlate baseline GDF-15 levels with physical and vascular health data in this population.

METHODS

Baseline blood samples were analysed using a GDF-15 ELISA assay kit. Correlations with baseline and 12-month outcome data, including measures of physical and vascular function, were performed.

RESULTS

A total of 147 individuals, mean age 76.8 ± 4.7 years, were included. 77 (52 %) were male. Baseline log₁₀GDF-15 showed significant correlations with age (r = 0.37, p < 0.001), total cholesterol (r = -0.33, p < 0.001) and 6-min walking distance (r = -0.37, p < 0.001). Age remained significantly associated with log₁₀GDF-15 in multivariable analysis (beta = -0.29, p = 0.001). Baseline log₁₀GDF-15 was significantly associated with decline in 6-min walk distance over 12 months (beta = -0.27, p = 0.01) in multivariable models. No significant correlations were seen with changes in vascular function over 12 months.

CONCLUSION

Baseline GDF-15 predicts declining physical, but not vascular, function in our population.

Twenty-Year Predictors of Peripheral Arterial Disease Compared With Coronary Heart Disease in the Scottish Heart Health Extended Cohort (SHHEC)

BACKGROUND

Coronary heart disease and peripheral arterial disease (PAD) affect different vascular territories. Supplementing baseline findings with assays from stored serum, we compared their 20-year predictors.

METHODS AND RESULTS

We randomly recruited 15 737 disease-free men and women aged 30 to 75 years across Scotland between 1984 and 1995 and followed them through 2009 for death and hospital diagnoses. Of these, 3098 developed coronary heart disease (19.7%), and 499 PAD (3.2%). Hazard ratios for 45 variables in the Cox model were adjusted for age and sex and for factors in the 2007 ASSIGN cardiovascular risk score. Forty-four of them were entered into parsimonious predictive models, tested by c-statistics and net reclassification improvements. Many hazard ratios diminished with adjustment and parsimonious modeling, leaving significant survivors. The hazard ratios were mostly higher in PAD. New parsimonious models increased the c-statistic and net reclassification improvements over ASSIGN variables alone but varied in their components and ranking. Coronary heart disease and PAD shared 7 of the 9 factors from ASSIGN: age, sex, family history, socioeconomic status, diabetes mellitus, tobacco smoking, and systolic blood pressure (but neither total nor high-density lipoprotein cholesterol); plus 4 new ones: NT-pro-BNP, cotinine, high-sensitivity C-reactive protein, and cystatin-C. The highest ranked hazard ratios for continuous factors in coronary heart disease were those for age, total cholesterol, high-sensitivity troponin, NT-pro-BNP, cotinine, apolipoprotein A, and waist circumference (plus 10 more); in PAD they were age, high-sensitivity C-reactive protein, systolic blood pressure, expired carbon monoxide, cotinine, socioeconomic status, and lipoprotein (a) (plus 5 more).

CONCLUSIONS

The mixture of shared with disparate determinants for arterial disease in the heart and the legs implies nonidentical pathogenesis: cholesterol dominant in the former, and inflammation (high-sensitivity C-reactive protein, diabetes mellitus, smoking) in the latter.

Prevalence of unrecognized myocardial infarction in a low-intermediate risk asymptomatic cohort and its relation to systemic atherosclerosis

Aims

Unrecognized myocardial infarctions (UMIs) have been described in 19–30% of the general population using late gadolinium enhancement (LGE) on cardiac magnetic resonance. However, these studies have focused on an unselected cohort including those with known cardiovascular disease (CVD). The aim of the current study was to ascertain the prevalence of UMIs in a non-high-risk population using magnetic resonance imaging (MRI).

Methods and results

A total of 5000 volunteers aged >40 years with no history of CVD and a 10-year risk of CVD of <20%, as assessed by the ATP-III risk score, were recruited to the Tayside Screening for Cardiac Events study. Those with a B-type natriuretic peptide (BNP) level greater than their gender-specific median were invited for a whole-body MR angiogram and cardiac MR including LGE assessment. LGE was classed as absent, UMI, or non-specific. A total of 1529 volunteers completed the imaging study; of these, 53 (3.6%) were excluded because of either missing data or inadequate LGE image quality. Ten of the remaining 1476 (0.67%) displayed LGE. Of these, three (0.2%) were consistent with UMI, whereas seven were non-specific occurring in the mid-myocardium (n = 4), epicardium (n = 1), or right ventricular insertion points (n = 2). Those with UMI had a significantly higher BNP [median 116 (range 31–133) vs. 22.6 (5–175) pg/mL, P = 0.015], lower ejection fraction [54.6 (36–62) vs. 68.9 (38–89)%, P = 0.007], and larger end-systolic volume [36.3 (27–61) vs. 21.7 (5–65) mL/m², P = 0.014]. Those with non-specific LGE had lower diastolic blood pressure [68 (54–70) vs. 72 (46–98) mmHg, P = 0.013] but no differences in their cardiac function.

Conclusion

Despite previous reports describing high prevalence of UMI in older populations, in a predominantly middle-aged cohort, those who are of intermediate or low cardiovascular risk have a very low risk of having an unrecognized myocardial infarct.

MRI of the left atrium at 3T: evaluation of measurement reproducibility in healthy volunteers and patients with cardiovascular disease

Background Left ventricular (LV) function has traditionally been the focus for cardiac magnetic resonance imaging (MRI) investigations, but similar methods can also be applied to the left atrium (LA). Previous studies elsewhere have almost entirely involved the use of 1.5T systems, but 3T MRI can provide faster data acquisition with thinner image slices, and may be more suitable for quantifying the structure and function of the LA. Purpose To evaluate 3T-MRI for LA volume assessments in: (i) healthy volunteers (HV); (ii) patients with LV-hypertrophy and ischemia (LVHI); and (iii) patients with LV-hypertrophy and diabetes (LVHD). Material and Methods Participants were imaged using a balanced steady-state free precession sequence. Healthy volunteers were scanned twice and patients were scanned on one occasion. Volumes were segmented by two observers, and coefficients of repeatability (CoR) were derived. Results For LA volumes (indexed to body surface area), CoRs were in the range of 1.3-4.6 mL/m². The LVHI patients had enlarged LA volumes (diastolic, 46.4 mL/m²; systolic, 25.9 mL/m²) and reduced ejection fraction (EF) (44.9%) relative to the HV (diastolic, 39.0 mL/m²; systolic, 17.8 mL/m²; EF, 54.5%) and LVHD groups (diastolic, 41.4 mL/m²; systolic, 20.2 mL/m²; EF, 50.7%). LA volumes were moderately correlated with LV mass in the HV group (R²= 0.59 for LA end-systolic volume), but became weaker (R²≤ 0.17) for patient groups. Conclusion 3T-MRI derived LA volume measurements are simple and repeatable, and can elicit clear differences between LVHI patients and HVs. These MRI endpoints provide scope for improved radiological interpretation of LA structure and function, and the high degree of repeatability validates their use for longitudinal investigations where precision work is essential.

Assessment of proximal pulmonary arterial stiffness using magnetic resonance imaging: effects of technique, age and exercise

Introduction

To compare the reproducibility of pulmonary pulse wave velocity (PWV) techniques, and the effects of age and exercise on these.

Methods

10 young healthy volunteers (YHV) and 20 older healthy volunteers (OHV) with no cardiac or lung condition were recruited. High temporal resolution phase contrast sequences were performed through the main pulmonary arteries (MPAs), right pulmonary arteries (RPAs) and left pulmonary arteries (LPAs), while high spatial resolution sequences were obtained through the MPA. YHV underwent 2 MRIs 6 months apart with the sequences repeated during exercise. OHV underwent an MRI scan with on-table repetition. PWV was calculated using the transit time (TT) and flow area techniques (QA). 3 methods for calculating QA PWV were compared.

Results

PWV did not differ between the two age groups (YHV 2.4±0.3/ms, OHV 2.9±0.2/ms, p=0.1). Using a high temporal resolution sequence through the RPA using the QA accounting for wave reflections yielded consistently better within-scan, interscan, intraobserver and interobserver reproducibility. Exercise did not result in a change in either TT PWV (mean (95% CI) of the differences: −0.42 (−1.2 to 0.4), p=0.24) or QA PWV (mean (95% CI) of the differences: 0.10 (−0.5 to 0.9), p=0.49) despite a significant rise in heart rate (65±2 to 87±3, p<0.0001), blood pressure (113/68 to 130/84, p<0.0001) and cardiac output (5.4±0.4 to 6.7±0.6 L/min, p=0.004).

Conclusions

QA PWV performed through the RPA using a high temporal resolution sequence accounting for wave reflections yields the most reproducible measurements of pulmonary PWV.

Multicentre, prospective, randomised, open-label, blinded end point trial of the efficacy of allopurinol therapy in improving cardiovascular outcomes in patients with ischaemic heart disease: protocol of the ALL-HEART study

INTRODUCTION

Ischaemic heart disease (IHD) is one of the most common causes of death in the UK and treatment of patients with IHD costs the National Health System (NHS) billions of pounds each year. Allopurinol is a xanthine oxidase inhibitor used to prevent gout that also has several positive effects on the cardiovascular system. The ALL-HEART study aims to determine whether allopurinol improves cardiovascular outcomes in patients with IHD.

METHODS AND ANALYSIS

The ALL-HEART study is a multicentre, controlled, prospective, randomised, open-label blinded end point (PROBE) trial of allopurinol (up to 600 mg daily) versus no treatment in a 1:1 ratio, added to usual care, in 5215 patients aged 60 years and over with IHD. Patients are followed up by electronic record linkage and annual questionnaires for an average of 4 years. The primary outcome is the composite of non-fatal myocardial infarction, non-fatal stroke or cardiovascular death. Secondary outcomes include all-cause mortality, quality of life and cost-effectiveness of allopurinol. The study will end when 631 adjudicated primary outcomes have occurred. The study is powered at 80% to detect a 20% reduction in the primary end point for the intervention. Patient recruitment to the ALL-HEART study started in February 2014.

ETHICS AND DISSEMINATION

The study received ethical approval from the East of Scotland Research Ethics Service (EoSRES) REC 2 (13/ES/0104). The study is event-driven and results are expected after 2019. Results will be reported in peer-reviewed journals and at scientific meetings. Results will also be disseminated to guideline committees, NHS organisations and patient groups.

TRIAL REGISTRATION NUMBER

32017426, pre-results.

Defining myocardial tissue abnormalities in end-stage renal failure with cardiac magnetic resonance imaging using native T1 mapping

Noninvasive quantification of myocardial fibrosis in end-stage renal disease is challenging. Gadolinium contrast agents previously used for cardiac magnetic resonance imaging (MRI) are contraindicated because of an association with nephrogenic systemic fibrosis. In other populations, increased myocardial native T1 times on cardiac MRI have been shown to be a surrogate marker of myocardial fibrosis. We applied this method to 33 incident hemodialysis patients and 28 age- and sex-matched healthy volunteers who underwent MRI at 3.0T. Native T1 relaxation times and feature tracking–derived global longitudinal strain as potential markers of fibrosis were compared and associated with cardiac biomarkers. Left ventricular mass indices were higher in the hemodialysis than the control group. Global, Septal and midseptal T1 times were all significantly higher in the hemodialysis group (global T1 hemodialysis 1171 ± 27 ms vs. 1154 ± 32 ms; septal T1 hemodialysis 1184 ± 29 ms vs. 1163 ± 30 ms; and midseptal T1 hemodialysis 1184 ± 34 ms vs. 1161 ± 29 ms). In the hemodialysis group, T1 times correlated with left ventricular mass indices. Septal T1 times correlated with troponin and electrocardiogram-corrected QT interval. The peak global longitudinal strain was significantly reduced in the hemodialysis group (hemodialysis -17.7±5.3% vs. -21.8±6.2%). For hemodialysis patients, the peak global longitudinal strain significantly correlated with left ventricular mass indices (R = 0.426), and a trend was seen for correlation with galectin-3, a biomarker of cardiac fibrosis. Thus, cardiac tissue properties of hemodialysis patients consistent with myocardial fibrosis can be determined noninvasively and associated with multiple structural and functional abnormalities.

Statin therapy increases vascular sensitivity to angiotensin II in hypercholesterolaemic patients

Introduction Cross-talk between various cardiovascular risk factors has been suggested by a number of studies. This study examines the interaction between hypercholesterolaemia and the renin-angiotensin system in vivo in man.

Methods We performed a randomised, placebo-controlled, double-blind crossover study on 40 hypercholesterolaemic patients, comparing cholesterol-lowering therapy with a statin for six months versus placebo. Brachial artery function was assessed by bilateral venous occlusion plethysmography using intra-arterial infusions of the endothelial-dependent vasoconstrictors, angiotensin I (Ang I) and angiotensin II (Ang II), to measure vascular angiotensin-converting enzyme (ACE) and Ang II receptor response respectively. The endothelial-independent vasoconstrictor, noradrenaline, was used as a control vasoconstrictor. Results were analysed by multiple analysis of variance and statistical significance

Cholesterol-lowering treatment with a statin was taken as a p value <0.05. Results Cholesterol-lowering treatment with alstatin significantly reduced the mean total cholesterol level to 5.71 mmol/L vs. 7.57 mmol/L on placebo (p<0.0001). Hypercholesterolaemia significantly increased the vasoconstriction response to noradrenaline (placebo versus statin treatment; p=0.046). In hypercholesterolaemia, there was a strong trend towards a reduction in the vasoconstriction response to Ang I (placebo versus statin treatment; p=0.089). In hypercholesterolaemia, the vasoconstriction response to Ang II was significantly reduced (placebo versus statin treatment; p=0.01).

Conclusions Our in vivo results show that, unlike some other previous work, hypercholesterolaemia is associated with down-regulation of the vasoconstrictor response to Ang II and that statin therapy up-regulates the local vasoconstrictor response to Ang II. The possibility now arises that, in man, statins alter the balance between AT1-receptors and AT2-receptors.

Tonic levels of angiotensin II reduce tonic levels of vascular nitric oxide even in salt-replete man

Introduction

Losartan improves stimulated endothelial function in patients with cardiovascular disease, but there are no data to establish whether losartan has this effect in normal man. Furthermore, whether losartan improves basal nitric oxide (NO) activity is controversial. We therefore examined whether treatment with losartan improved basal NO activity in normal, salt-replete man. If so, this would imply that tonic levels of angiotensin II (Ang II) reduce tonic basal levels of NO, even in salt-replete normal man.

Methods

We performed a randomised, placebo-controlled, double-blind crossover study in 24 healthy volunteers, comparing losartan 50 mg daily for one month versus placebo. Brachial artery endothelial function was assessed by bilateral venous occlusion plethysmography, measuring the response to intra-arterial infusions of the endothelial-dependent and endothelial-independent vasodilators, acetylcholine and sodium nitroprusside respectively and the endothelial-dependent vasoconstrictor NG-monomethyl-L-arginine. Results were analysed by multiple analysis of variance and statistical significance was taken as a p value of ≤ 0.05.

Results

Losartan significantly increased the vasoconstriction in response to N G-monomethyl-L-arginine (-37 2% vs. -32+2%, losartan vs. placebo; p=0.05). Losartan improved the vasodilatation response to acetylcholine; however, this result did not reach significance (214+2 0% vs. 174+20%, losartan vs. placebo; p=0.15). Losartan did not affect the response to nitroprusside (172+15% vs. 176+16%, losartan vs. placebo; p=0.84). There was no significant difference in blood pressure between the two study days.

Conclusions

Losartan improves basal NO bioactivity in healthy salt-replete volunteers. Even in salt-replete man, basal Ang II levels exert a tonic effect, which reduces basal NO.