Biomarkers associated with vulnerable plaques

Background

Cardiovascular heart disease is the leading cause of mortality worldwide, with the rupture or thrombosis of an atherosclerotic plaque being the main reason behind an acute coronary syndrome. It has already been established that the morphology of atherosclerotic plaques determine their stability. A lipid rich lesion with a thin fibrous cap is more prone to rupture compared to solid fibrous lesions. In the PROSPECTII study we used Near infrared spectroscopy (NIRS) and Intravascular ultrasound (IVUS) to identify atherosclerotic plaques in the coronary arteries; NIRS-derived lipid core burden index (LCBI) and IVUS-derived plaque burden (PB) identified plaques that caused adverse cardiovascular events.

Purpose

Our aim is to find biomarkers associated with LCBI or PB, to understand the development of vulnerable plaques.

Methods

902 patients were enrolled in this study after successful percutaneous coronary intervention (PCI). A combined NIRS-IVUS catheter was then used to analyze approximately 200m of coronary arteries. Blood samples for biomarker analysis were taken before the PCI procedure and plasma levels of 182 proteins associated with cardiovascular disease were assessed using a novel method for measuring proximity extension assay. Adjusted linear regression models were calculated between the biomarkers and the outcomes of interest, followed by a false discovery rate (FDR) correction.

Results

We found 24 proteins associated with plaque burden and 28 proteins associated with LCBI after using a cut off of two tailed P value <0.05. An overlap of 8 biomarkers could be seen between the two groups. After adjusting the P values with FDR, Angiopoeitin like 3 (ANGPTL3) retained its association to LCBI, and Interleukin 18 receptor 1 (IL18R1) and colony stimulating factor 1 (CSF-1) to plaque burden.

Conclusion

We were able to identify different biomarker patterns associated with plaque burden compared to lipid rich vulnerable plaques. ANGPTL3 was shown to only have an association with lipid rich plaques and not with solid fibrous lesions which further supports its role in vulnerable plaques.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Abbott Vascular, Infraredx, and The Medicines Company

Interrelation between baseline plaque characteristics and changes in coronary atherosclerosis with the PCSK9-inhibitor alirocumab: insights from the PACMAN-AMI randomized trial

Background

Patients with acute myocardial infarction (AMI) frequently experience recurrent atherothrombotic events, largely attributable to non-culprit lesions with high-risk characteristics. Statins can halt the progression of coronary atherosclerosis, and addition of protein convertase subtilisin/kexin type 9-inhibitors (PCSK9i) results in incremental low-density lipoprotein cholesterol (LDL-C) lowering and atheroma regression.

Purpose

We sought to examine the interrelation between baseline imaging characteristics, on-treatment LDL-C levels, and changes in coronary atherosclerosis as assessed by serial, multi-modality intracoronary imaging in patients with AMI.

Methods

This is a post hoc analysis from the PACMAN-AMI randomized trial. Patients were randomly allocated to biweekly alirocumab 150 mg vs. placebo on top of high-intensity statin initiated within 24h of presentation with AMI, and underwent serial imaging of the two non-infarct-related arteries at baseline and after 52 weeks. The primary endpoint was percent atheroma volume (PAV) by intravascular ultrasound (IVUS). Powered secondary endpoints were maximal lipid core burden index (maxLCBI4mm) by near-infrared spectroscopy (NIRS) and minimum fibrous cap thickness (FCTmin) by optical coherence tomography (OCT).

Results

Of 300 randomized patients (mean age 58.5±9.8 years, 18.7% women, baseline LDL-C 3.94±0.87 mmol/L), IVUS was serially performed in 265 patients (537 arteries). LDL-C levels decreased to 1.92±0.79 mmol/L with placebo and 0.61±0.61 mmol/L with alirocumab (p<0.001). Compared with placebo (statin alone), alirocumab added to statin resulted in greater PAV reduction (−2.13% vs. −0.92%; p<0.001), greater maxLCBI4mm reduction (−79.42 vs. −37.60; p=0.006), and greater increase in FCTmin (62.67 vs. 33.19 μm; p=0.001). Changes in PAV and maxLCBI4mm were inversely related to on-treatment LDL-C levels, and change in FCTmin was positively related to on-treatment LDL-C levels (Figure 1). Across all patients, we found significant, inverse relationships between change in PAV and baseline PAV [slope: −0.072 (95% CI −0.101 to −0.042); p<0.001], between change in maxLCBI4mm and baseline maxLCBI4mm [slope: −0.437 (95% CI −0.505 to −0.369); p<0.001], and between change in FCTmin and baseline FCTmin [slope: −0.436 (95% CI −0.541 to −0.332); p<0.001]; these findings indicate greater PAV and maxLCBI4mm regression in lesions with greater PAV and LCBI4mm at baseline, and greater fibrous cap thickening in lesions with thinner fibrous caps at baseline.

Conclusion

In this study of intensive LDL-C lowering treatment initiated in the acute AMI setting, more favorable plaque changes were observed in patients with lower on-treatment LDL-C levels and in lesions with more adverse baseline plaque characteristics. Whether AMI patients with high-risk plaque features might derive greater clinical benefit from early initiation of intensive LDL-C-lowering therapies requires further investigation.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Sanofi, Regeneron

Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving a ventricular fibrillation out of hospital cardiac arrest

Introduction

Prediction of ventricular arrhythmia recurrence in survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring and dedicated late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) software allows for characterization of left ventricular scarring, including differentiation between core, border zone (BZ) and BZ channels that represent potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events.

Purpose

Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VF-OCHA and investigate its potential role for the risk of new ventricular arrhythmia.

Methods

Between 2018 and 2021, a total of 130 VF-OHCA patients had CMR, of which we included 28 patients with LGE-CMR before ICD implantation for secondary prevention. A total of 15 (54%) patients had signs of acute or chronic ischemic heart disease (IHD); and 13 (46%) patients had arrhythmogenic cardiomyopathy (ACM). Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software. To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1A+B).

Results

The median age was 56 years; 86% were men and the median left ventricular ejection fraction was 50±11%. A total of 16 (57%) patients had an inferior scar on LGE-CMR, and 8 (29%) patients with IHD were incompletely revascularized. After a median follow-up of 98 days, 9 (32%) patients (6/9 with IHD, including 5/6 incompletely revascularized; 3/9 with ACM) had recurrence of ventricular arrhythmia (6/9 monomorphic ventricular tachycardia (VT)). A significantly higher number of patients with BZ channels had recurrence of ventricular arrhythmia compared with patients without BZ channels (7/11 vs. 2/17; P=0.01) (Figure 2). The number of BZ channels (3±1 vs. 2±1; P=0.13); scar mass (21±8g vs. 14±11g; P=0.21); core mass (7±4g vs. 4±5g; P=0.14); and BZ mass (11±5g vs. 9±7g; P=0.42) were insignificantly higher in patients with recurrent ventricular arrhythmia compared with patients without.

Conclusion

Borderzone channels analyzed by LGE-CMR were associated with subsequent recurrence of ventricular arrhythmia in patients with out of hospital cardiac arrest caused by ventricular fibrillation.

Funding Acknowledgement

Type of funding sources: None.

Clinical risk factors associated with ventricular fibrillation during first ST-elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union’s Horizon 2020 research and innovation programme under acronym ESCAPE-NET, registered under grant agreement No 733381

Introduction

Sudden cardiac death (SCD) remains a major public health issue. Most cases in the general population are caused by ischemic heart disease, and often occur in patients without known ischemic heart disease. The assessment of risk factors may point to novel causal pathways or new targets for intervention and risk prediction of SCD.

Objective

The aim of this study was to evaluate the effect of family history of sudden death, prior history of atrial fibrillation (AF), and anterior infarct location on ECG on the development of ventricular fibrillation (VF) during first ST-elevation myocardial infarction (STEMI).

Methods

We performed individual participant data meta-analyses of three European case-control studies including first STEMI patients (aged 18-80 years) with VF (cases) and without VF (controls) before revascularization (GEVAMI, AGNES, and PREDESTINATION). Analyses were done using fixed-effect, inverse variance weighted meta-analysis and multivariable logistic regression. Potential confounding variables were identified using causal diagrams and missing data were handled with multiple imputation for each cohort separately.

Results

We included 1664 cases and 2497 controls (median age (IQR) = 59 (51-67) years, 20% females) in the analyses. After adjusting for potential confounding, we found an independent and additive association between the three exposures and VF (see picture): for family history of sudden death odds ratio (OR) 1.59 (95% confidence interval: 1.37-1.85), for AF OR 2.41 (1.49-3.89), and for anterior myocardial infarction OR 1.50 (1.32-1.71). Further investigation indicated increased effect of family history with multiple sudden deaths in the family, a stronger effect of AF on VF developing within the first minutes of symptoms, and the effect of anterior infarctions being modified by enzymatically determined infarct size. The three risk factors showed an additive effect: with one factor present OR 1.59 (1.38-1.84), two factors OR 2.41 (1.95-2.99), and all three factors OR 5.49 (1.43-21.1). Complete case analysis gave similar results for all analyses.

Conclusions

Family history of sudden death, history of AF, and anterior infarct location with significant interaction with enzymatic infarct size were all independently and additively associated with an increased risk of VF in patients with a first STEMI.

Scar related border zone channels assessed with cardiac MRI are associated with ventricular arrhythmia in patients with ST-segment elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Introduction

Prediction of scar-related ventricular arrhythmia in ST-Segment Elevation Myocardial Infarction (STEMI) is important, but currently difficult. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits characterization of left ventricular (LV) ischemic scars, including differentiation between core, border zone (BZ) and BZ channels. The latter represents potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events. We hypothesized that detailed BZ channel characterization potentially serves as a risk marker for ventricular arrhythmia, therefore contributing to risk stratification following STEMI.

Purpose

The aim of this study was to assess scar-related arrhythmic BZ channels with advanced CMR in STEMI patients developing subsequent ventricular arrhythmia compared with controls.

Methods

This is a CMR sub-study of the DANAMI-3 STEMI multicenter trial (year 2011, n=1234) and Danegaptide phase II proof-of-concept clinical trial (year 2013, n=591). All patients were admitted for primary PCI in all primary PCI centers in Denmark. A total of 779 patients had a 3-month follow-up CMR. Of these, 21 patients subsequently experienced ventricular arrhythmia during 68 months of follow-up and were randomly matched 1:2 with 42 controls, who constituted the study population. Matching were based on left ventricular ejection fraction (LVEF), infarct location, culprit vessel, and revascularization status in patients with multivessel disease. Ischemic scar tissue including core, BZ and BZ channels were automatically detected by a specialized investigational software (1). To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1).

Results

We included 63 patients (median age: 58.0 years; 84% men; median LVEF: 45 ± 10%), of whom 30 (48%) patients had an anterior located infarction, and 45 (71%) patients were completely revascularized. The median time from STEMI to a ventricular arrhythmic event was 3 ± 2 years. A significantly higher number of patients with ventricular arrhythmia had BZ channels (n=16 (76%) vs. n=18 (43%), P=0.02) including an increased number of BZ channels (2 ± 2 vs. 1 ± 1, P=0.02) compared with controls. Patients with subsequent ventricular arrhythmia had a larger scar mass (core mass + BZ mass) (27 ± 17g vs. 19 ± 11g; P=0.03), core mass (9 ± 8g vs. 6 ± 5g; P=0.06) and BZ mass (18 ± 10g vs. 13 ± 7g; P=0.01).

Conclusion(s)

Border zone channels visualized by LGE-CMR were associated with subsequent development of ventricular arrhythmia in patients with STEMI and may serve as risk stratification following STEMI.

Outcomes of rapid digital transformation of large-scale communications during the COVID-19 pandemic

Objective This study examined the content and impact of a new digital communication medium, called a VIDCAST, implemented at a large hospital and health service when the COVID-19 pandemic was announced, and the key concerns held by staff at the time when the health service was preparing for the COVID-19 pandemic to arrive in this health service. Methods A mixed-methods approach was used. Thematic analysis of 20 transcripts of daily VIDCASTS broadcast between 30 March and 24 April 2020 was undertaken, in addition to descriptive analysis of feedback from an anonymous online survey. Results Survey feedback from 322 staff indicated almost universal satisfaction with this new communication method. The VIDCASTS provided a new COVID-safe method for the Executive to connect to staff at a time of uncertainty. Thematic analysis of the content of the VIDCASTS revealed three themes: 'Accurate Information', 'Reassurance and Support' and 'Innovation'. The Executive was able to reassure staff about what the organisation was doing to safeguard the health and wellbeing of all, and enabled an effective response to the pandemic. Conclusions The digital communication channel of VIDCASTS, rapidly operationalised at a major Australian hospital and health service in March 2020, provided important information and support for staff as it prepared for the anticipated COVID-19 surge. What is known about the topic? When the COVID-19 pandemic began, traditional face-to-face staff meetings were disrupted and many hospitals and their staff were left scrambling for information, and for reassurance about their safety, as they prepared to receive increasing numbers of COVID-19 patients. What does this paper add? The implementation of a digital communication tool was able to address many of the concerns raised by hospital staff in other geographic locations dealing with surging COVID-19 cases and underpinned a globally leading COVID-19 response. What are the implications for practitioners? New digitised communication methods provided an effective vehicle to inform and support staff in the early stages of pandemic preparation.

Quantitative flow ratio to predict non-target-vessel-related events at 5 years in STEMI patients undergoing angiography-guided revascularization

Background

In patients with ST-segment-elevation myocardial infarction (STEMI), angiography-based complete revascularization is associated with superior outcomes compared with culprit-lesion-only percutaneous coronary intervention (PCI). Quantitative Flow Ratio (QFR) is a novel, non-invasive, vasodilator-free method to assess the hemodynamic significance of coronary stenoses.

Purpose

To investigate the incremental value of QFR over angiography alone in the assessment of non-culprit lesions (NCL) in STEMI patients undergoing primary PCI.

Methods

In the randomized, multicenter COMFORTABLE AMI trial, STEMI patients underwent angiography-guided complete revascularization. QFR was determined in untreated non-target vessels by assessors blinded for clinical outcomes.

Results

Out of 1161 STEMI patients, 946 vessels in 617 patients could be analyzed by QFR. At 5-year follow-up, the rate of the primary endpoint cardiac death, non-target vessel myocardial infarction (non-TV-MI) and clinically indicated, non-target vessel revascularization (non-TVR) was significantly higher in patients with QFR ≤0.80 compared with QFR >0.80 (62.9% vs. 12.7%, HR 7.20, 95% CI 4.46–11.62, p<0.001), driven by higher rates of non-TV-MI (15.4% vs. 3.6%, HR 4.59, 95% CI 1.72–12.23, p=0.002) and non-TVR (58.6% vs. 7.7%, HR 10.99, 95% CI 6.39–18.91, p<0.001). No significant differences for cardiac death were observed. Multivariate analysis identified QFR ≤0.80, MI SYNTAX score and left ventricular function as independent predictors of the primary endpoint. QFR ≤0.80 showed an accuracy of 86.1%, sensitivity of 23.2%, specificity of 97.5%, positive predictive value of 62.9% and negative predictive value of 87.5% for the prediction of the primary endpoint.

Conclusions

Our study results suggest incremental value of QFR over angiography-guided PCI for NCL among STEMI patients undergoing primary PCI.

Kaplan-Meier curves of primary endpoint

Funding Acknowledgement

Type of funding source: None

Up-regulation of oxytocin receptors in non-pregnant rat myometrium by isoproterenol: effects of steroids

The objective of the present study was to further elucidate our previous observation that beta2-adrenoceptor activation induces oxytocin receptor (OTR) expression in rat myometrium. We wanted to investigate whether the mechanism behind this effect was under the influence of gonadal steroids. Ovariectomized non-pregnant rats were treated with estrogen, progesterone or a combination of both for 3 days. Some rats were concomitantly treated with isoproterenol. Estrogen treatment increased both OTR mRNA production and maximal binding of [3H]-oxytocin to isolated myometrial plasma membranes, but it did not affect contractility of isolated uterine strips challenged with oxytocin. When the estrogen regimen was combined with isoproterenol treatment, an augmented maximal contractile response (Emax) to oxytocin was observed although no further increase in OTR mRNA and binding was seen. Progesterone treatment did not in itself alter OTR mRNA, OTR binding or Emax. However, OTRs were induced at the level of gene expression when progesterone was supplemented with isoproterenol infusion. Finally, progesterone suppressed the effect of estrogen on OTR mRNA production and binding when the two compounds were administered together. However, when isoproterenol treatment was added this effect was abolished and Emax was enhanced more than that seen following treatment with estrogen alone. These data suggest that beta2-adrenoceptor activation represents an important regulator of OTR expression/function in estrogen- and progesterone-dominated rat myometrium.

Osmoregulatory control of renal sodium excretion after sodium loading in humans

The hypothesis that renal sodium handling is controlled by changes in plasma sodium concentration was tested in seated volunteers. A standard salt load (3.08 mmol/kg body wt over 120 min) was administered as 0.9% saline (Isot) or as 5% saline (Hypr) after 4 days of constant sodium intake of 75 (LoNa+) or 300 mmol/day (HiNa+). Hypr increased plasma sodium by approximately 4 mmol/l but increased plasma volume and central venous pressure significantly less than Isot irrespective of diet. After LoNa+, Hypr induced a smaller increase in sodium excretion than Isot (48 +/- 8 vs. 110 +/- 17 micromol/min). However, after HiNa+ the corresponding natriureses were identical (135 +/- 33 vs. 139 +/- 39 micromol/min), despite significant difference between the increases in central venous pressure. Decreases in plasma ANG II concentrations of 23-52% were inversely related to sodium excretion. Mean arterial pressure, plasma oxytocin and atrial natriuretic peptide concentrations, and urinary excretion rates of endothelin-1 and urodilatin remained unchanged. The results indicate that an increase in plasma sodium may contribute to the natriuresis of salt loading when salt intake is high, supporting the hypothesis that osmostimulated natriuresis is dependent on sodium balance in normal seated humans.