The association between central ambulatory blood pressure and end-organ damage

Background/Introduction

Central blood pressure (BP) measured in the clinic relates more strongly to end-organ damage and may be superior to brachial BP in predicting cardiovascular events. Measurement of central ambulatory BP (ABP) is now possible and emerging data suggest that central ABP is better correlated with left ventricular mass index (LVMI) than brachial ABP.1,2 However, the association between central ABP and other measures of end-organ damage remains unclear.

Purpose

We investigated the association between brachial or central ABP and end-organ damage, in a large community-based population of untreated individuals.

Method

1091 participants (mean age 45±18 years; 589 females) had simultaneous measurements of brachial and central ABP over 24 hours, using the Mobil-O-Graph device. Central ABP was derived using two waveform calibration methods (1: mean/diastolic BP; 2: systolic/diastolic BP). Participants also underwent measurement of aortic pulse wave velocity (aPWV; SphygmoCor device) in the clinic. In a subset of 675 individuals, LVMI was assessed by echocardiography and in 610 individuals, carotid intima-media thickness (CIMT) was measured, using ultrasound. 24-hour and daytime brachial and central ambulatory systolic BP (ASBP) and pulse pressure (APP) were considered.

Results

The Pearson's coefficient for each correlation is listed in Table 1. LVMI was most strongly correlated with 24-hour central ASBP, using calibration method 1 (MAP/DBP; r=0.403, P<0.001). CIMT was most strongly correlated with daytime central ASBP, again derived from calibration method 1 (r=0.341, p<0.001), whereas aPWV measured in the clinic, was most strongly correlated with 24-hour central ASBP, derived from calibration method 2 (SBP/DBP; r=0.441, P<0.001). Based on z statistics, all correlations reported above were significantly stronger than equivalent correlations using brachial ASBP (P<0.001 for all three comparisons of correlation coefficients).

Conclusion

Measurement of central ABP relates more closely to end-organ damage than equivalent measures based on brachial ABP. Central ABP may provide valuable additional information concerning cardiovascular risk above and beyond brachial ABP.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): British Heart Foundation

Low dose interleukin-2 in patients with stable ischaemic heart disease and acute coronary syndrome (LILACS)

Background

Regulatory T lymphocytes (Tregs) are critical for immune homeostasis. Pre-clinical models have demonstrated that Tregs can modulate post-ischaemic immune responses and promote myocardial healing. Patients with ischaemic heart disease (IHD) display reduced anti-inflammatory Tregs and increased pro-inflammatory effector T cells (Teffs). Low-dose interleukin-2 (ld-IL2) has been shown to increase Tregs in patients with autoimmune diseases but is currently contraindicated in patients with IHD.

Purpose

To assess the safety and pharmacodynamic effect of ld-IL-2 in patients with IHD.

Methods

LILACS was a prospective, randomised, double-blind, placebo-controlled, dose-escalation, Phase I/II clinical trial, which tested ld-IL-2 (aldesleukin) given once daily subcutaneously, for five consecutive days. In Part A, 25 patients with stable IHD were randomised (drug:placebo ratio of 3:2) in 5 dose groups (0.3, 0.6, 1.2, 2.4 and 3x106 IU/day); whilst in Part B, 16 patients with non-ST elevation myocardial infarction (NSTEMI) were randomised (drug:placebo ratio of 6:2) in two dose groups (1.5 and 2.5x106 IU/day). Follow up was performed the day after dosing and again 7 days later. Doses were determined after blinded review. An independent committee reviewed unblinded data prior to commencing Part B. The primary endpoint was safety in parts A and B. Additionally in Part B, a co-primary endpoint was to calculate the dose required to increase Tregs by 75%. [NCT03113773]

Results

Ld-IL2 was well tolerated for all dose groups with the commonest adverse events being mild injection site reactions. Two serious adverse events, not considered to be drug related, occurred in Part B – one prior to dosing and resulting in withdrawal. The other was a recurrent NSTEMI after dosing ended in a patient with severe triple vessel coronary artery disease awaiting urgent bypass surgery. In Part A, Tregs increased with dose escalation whilst no Teff increases were noted (Figure 1A). In Part B, patients treated with 1.5 and 2.5x106 IU/day doses had a median increase in Tregs of 80.5% (CI 36.2–124.7%, p=0.003) and 108.3% (CI 55.3–161.3%, p=0.002) respectively (Figure 1B). A linear regression model estimated an increase of 43.3% (CI 23.6–63.0%, p=0.0003) per unit dose. The estimated dose to achieve a 75% increase in Tregs was 1.46x106 IU/day (CI 1.06–1.87). No increase in Teffs cells were seen however, a dose-dependent decrease was measured in B cells, whilst NK cells and eosinophils increased at the top 2.5 and 3x106 IU/day dose. A panel of 29 cytokines and chemokines showed a dose-dependent type 1 and 2 cytokine response. Single-cell RNA sequencing was performed on immune cells before and after dosing.

Conclusions

Ld-IL2 was safe and well-tolerated. An induction dose of 1.5x106 IU per day for 5 days provided an effective expansion of Tregs without increasing Teffs. This work provides important data for the future therapeutic use of ld-IL-2 which is ongoing.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Medical Research Council, British Heart Foundation Cambridge Centre of Excellence

P373 Left atrial mechanics and aortic stiffness following high intensity interval training: a randomised controlled study

Background

Physical inactivity is associated with an increased risk of cardiovascular disease. High intensity interval training (HIIT) has been shown to improve important health parameters, including aerobic capacity, arterial blood pressure, cardiac autonomic modulation and left ventricular mechanics. However, adaptations in left atrial (LA) mechanics and aortic stiffness remain unclear. Therefore, the aim of the present study was to assess any left atrial and aortic adaptations to HIIT.

Methods

Forty-one physically inactive males and females (aged 23 ± 2.7 years) volunteered for the study. Participants were randomised to either a 4-week HIIT intervention (n = 21) or 4-week control period (n = 20). The HIIT protocol consisted of 3 x 30-second maximal cycle ergometer sprints with a resistance of 7.5% body weight, interspersed with 2-minutes of active unloaded recovery. Speckle tracking imaging of the left atrium and M-Mode tracing of the aorta was performed pre and post HIIT and control period using commercially available software (EchoPac; GE Medical Systems). Analysis of covariance, with baseline measures as the covariate, was used to explore any differences in left atrial mechanics and aortic stiffness between the intervention and control groups. Stepwise linear regression analysis using LA stiffness as the dependent variable was conducted.

Results

Following 4-weeks of HIIT, there was significant improvement in LA mechanics, including LA reservoir (13.9 ± 13.4%, p = 0.033) and LA stiffness (-0.05 ± 0.04%-1, p = 0.032) compared to the control condition. In addition, improvements were observed in aortic distensibility (2.1 ± 2.7 cm2 × dyn×-1 × 103, p = 0.031) and aortic stiffness index (-2.6 ± 4.6, p = 0.041) compared to the control condition. In stepwise linear regression analysis, aortic distensibility change was significantly associated with LA stiffness change (p = 0.002), with an R2 of 0.613.

Conclusion

A short-term programme of HIIT was associated with a significant improvement in LA mechanics and aortic stiffness. These adaptations may have important health implications and contribute to the improved left ventricular diastolic and systolic mechanics, aerobic capacity and reduced arterial blood pressure previously documented following HIIT.

The role of epoxyeicosatrienoic acids in the cardiovascular system

There is increasing evidence suggesting that epoxyeicosatrienoic acids (EETs) play an important role in cardioprotective mechanisms. These include regulating vascular tone, modulating inflammatory responses, improving cardiomyocyte function and reducing ischaemic damage, resulting in attenuation of animal models of cardiovascular risk factors. This review discusses the current knowledge on the role of EETs in endothelium-dependent control of vascular tone in the healthy and in subjects with cardiovascular risk factors, and considers the pharmacological potential of targeting this pathway.

Increased incidence of interatrial block in younger adults with cryptogenic stroke and patent foramen ovale

Background

Stroke is often unexplained in younger adults, although it is often associated with a patent foramen ovale (PFO). The reason for the association is not fully explained, and mechanisms other than paradoxical embolism may be involved. Young stroke patients with PFO have more atrial vulnerability than those without PFO. It is plausible that stretching of the interatrial septum may disrupt the interatrial conduction pathways causing interatrial block (IAB). IAB is associated with atrial fibrillation, dysfunctional left atria and stroke.

Methods

Electrocardiogram (ECG) characteristics of prospectively recruited young patients (≤55 years of age) with unexplained stroke (TOAST and A-S-C-O) were compared with control data. All stroke cases underwent bubble contrast transthoracic and transoesophageal echography. IAB was defined as a P-wave duration of ≥110 ms. ECG data were converted to electronic format and analysed in a blind manner.

Results

Fifty-five patients and 23 datasets were analysed. Patients with unexplained stroke had longer P-wave duration (p = 0.013) and a greater prevalence of IAB (p = 0.02) than healthy controls. Case status was an independent predictor of P-wave duration in a significant multivariate model. There was a significant increase in the proportion of cases with a PFO with IAB compared with cases without PFO and with controls (p = 0.005).

Conclusions

Young patients with unexplained stroke, particularly those with PFO, exhibit abnormal atrial electrical characteristics suggesting atrial arrhythmia or atrial dysfunction as a possible mechanism of stroke.

New acute and chronic black holes in patients with multiple sclerosis randomised to interferon beta-1b or glatiramer acetate

BACKGROUND

Hypointense lesions on T1 weighted MRI, referred to as black holes (BH), are a marker of demyelination/axonal loss in multiple sclerosis (MS). There is some evidence that glatiramer acetate (GA) may decrease the conversion of new brain lesions to BH.

METHODS

Monthly 3-Tesla brain MRI scans were used for up to 2 years to study the development and evolution of new BH in 75 patients with MS randomised to GA or Interferon beta-1b (IFNbeta1b) in the BECOME study.

FINDINGS

Of 1224 newly enhancing lesions (NEL) appearing at baseline through 24 months in 61 patients, 767 (62.7%) showed an acute BH (ABH). The majority of ABH were transient and of similar duration by treatment group. Of 571 ABH in which MRI follow-up scans were available for >or=1 year, 103 (18.8%) were still visible >or=12 months after onset and were considered chronic BH (CBH). Only 12.1% of the 849 NEL with MRI follow-up >or=1 year converted to CBH, 9.8% with IFNbeta1b and 15.2% with GA (p = 0.02). The conversion from ABH to CBH was also lower with IFNbeta1b (15.2%) than with GA (21.4%), of borderline significance (p = 0.06). The majority of patients who developed NEL did not develop CBH; however, about a quarter had conversion rates from ABH to CBH greater than 20%.

INTERPRETATION

Only a minority of new brain lesions in patients with MS treated with GA or IFNbeta1b convert to CBH.

Efficacy of treatment of MS with IFNbeta-1b or glatiramer acetate by monthly brain MRI in the BECOME study

BACKGROUND

There are no published MRI studies comparing interferon beta 1b (IFNbeta-1b) and glatiramer acetate (GA) for treatment of relapsing multiple sclerosis (MS).

OBJECTIVE

To compare the efficacy of IFNbeta-1b and GA for suppression of MS disease activity as evidenced on frequent brain MRI.

METHODS

A total of 75 patients with relapsing-remitting MS or clinically isolated syndromes were randomized to standard doses of IFNbeta-1b or GA and followed by monthly brain MRI for up to 2 years with a protocol optimized to detect enhancement. The primary outcome was the number of combined active lesions (CAL) per patient per scan during the first year, which included all enhancing lesions and nonenhancing new T2/fluid-attenuated inversion recovery (FLAIR) lesions. Secondary outcomes were the number of new lesions and clinical exacerbations over 2 years.

RESULTS

Baseline characteristics were similar between the groups. The primary outcome showed similar median (75th percentile) CAL per patient per scan for months 1-12, 0.63 (2.76) for IFNbeta-1b, and 0.58 (2.45) for GA (p = 0.58). There were no differences in new lesion or clinical relapses for 2 years. Only 4.4% of CAL on monthly MRI scans were nonenhancing new T2/FLAIR lesions.

CONCLUSION

Patients with relapsing multiple sclerosis randomized to interferon beta 1b or glatiramer acetate showed similar MRI and clinical activity.

Role of increased aortic stiffness in the pathogenesis of heart failure

Aortic stiffness is an independent predictor of cardiovascular mortality in a variety of patient groups including hypertensives and other unselected patients. Despite a sound pathophysiologic basis, termed the ventricular-vascular coupling mechanism, the relationship between aortic stiffness and heart failure has been less well studied. This review summarizes some important trials of aortic stiffness in cardiovascular disease risk prediction and progression to heart failure. Emerging targets for therapeutics and areas requiring more research are also discussed.