An assessment of the concentration-related prognostic value of cardiac troponin I following acute coronary syndrome

Cohort profile: Evaluation of the Methods and Management of Acute Coronary Events (EMMACE) Longitudinal Cohort

AIMS

The Evaluation of the Methods and Management of Acute Coronary Events (EMMACE) longitudinal cohort study aims to investigate health trajectories of individuals following hospitalization for myocardial infarction (MI).

METHODS AND RESULTS

EMMACE is a linked multicentre prospective cohort study of 14 899 patients with MI admitted to 77 hospitals in England who participated in the EMMACE-3 and -4 studies between 1st November 2011 and 24th June 2015. Long-term follow-up of the EMMACE cohorts was conducted through the EMMACE-XL (27th September 2020 to 31st March 2022) and EMMACE-XXL (1st July 2021 to 1st July 2023) studies. EMMACE collected individual participant data for health-related quality of life (HRQoL) measured by three-level EuroQol five-dimension and visual analogy scale at admission, 1 month, 6 months, 12 months, and 10 years follow-up, as well as medications, medication adherence, beliefs about medicines, Satisfaction with Information about Medicines Scale, and illness perceptions. Participant data were deterministically linked to the Myocardial Infarction National Audit Project (MINAP) for information on baseline treatments and comorbidities, Hospital Episode Statistics Admitted Patient Care (for cause-specific hospitalization data), and the Office for National Statistics (for mortality data) up to 2020.

CONCLUSION

EMMACE is a nationwide prospective cohort that will provide unique insights into fatal and non-fatal outcomes, medication adherence, and HRQoL following MI.Trial registration: ClinicalTrials.gov NCT01808027 and NCT01819103.

Targeting Ferroptosis against Ischemia/Reperfusion Cardiac Injury

Ischemic heart disease is a leading cause of death worldwide. Primarily, ischemia causes decreased oxygen supply, resulting in damage of the cardiac tissue. Naturally, reoxygenation has been recognized as the treatment of choice to recover blood flow through primary percutaneous coronary intervention. This treatment is the gold standard therapy to restore blood flow, but paradoxically it can also induce tissue injury. A number of different studies in animal models of acute myocardial infarction (AMI) suggest that ischemia-reperfusion injury (IRI) accounts for up to 50% of the final myocardial infarct size. Oxidative stress plays a critical role in the pathological process. Iron is an essential mineral required for a variety of vital biological functions but also has potentially toxic effects. A detrimental process induced by free iron is ferroptosis, a non-apoptotic type of programmed cell death. Accordingly, efforts to prevent ferroptosis in pathological settings have focused on the use of radical trapping antioxidants (RTAs), such as liproxstatin-1 (Lip-1). Hence, it is necessary to develop novel strategies to prevent cardiac IRI, thus improving the clinical outcome in patients with ischemic heart disease. The present review analyses the role of ferroptosis inhibition to prevent heart IRI, with special reference to Lip-1 as a promising drug in this clinicopathological context.

Myosin binding protein H-like (MYBPHL): a promising biomarker to predict atrial damage

Myosin binding protein H-like (MYBPHL) is a protein associated with myofilament structures in atrial tissue. The protein exists in two isoforms that share an identical amino acid sequence except for a deletion of 23 amino acids in isoform 2. In this study, MYBPHL was found to be expressed preferentially in atrial tissue. The expression of isoform 2 was almost exclusively restricted to the atria and barely detectable in the ventricle, arteria mammaria interna, and skeletal muscle. After atrial damage induced by cryo- or radiofrequency ablation, MYBPHL was rapidly and specifically released into the peripheral circulation in a time-dependent manner. The plasma MYBPHL concentration remained substantially elevated up to 24 hours after the arrival of patients at the intensive care unit. In addition, the recorded MYBPHL values were strongly correlated with those of the established biomarker CK-MB. In contrast, an increase in MYBPHL levels was not evident in patients undergoing aortic valve replacement or transcatheter aortic valve implantation. In these patients, the values remained virtually constant and never exceeded the concentration in the plasma of healthy controls. Our findings suggest that MYBPHL can be used as a precise and reliable biomarker to specifically predict atrial myocardial damage.

Cardiac troponin I exacerbates myocardial ischaemia/reperfusion injury by inducing the adhesion of monocytes to vascular endothelial cells via a TLR4/NF-κB-dependent pathway

Cardiac troponin I (cTnI), a biomarker for myocardial damage and risk stratification, may be involved in the pathogenesis of cardiovascular diseases, which was ascribed to the effect of cTnI auto-antibodies. Whether or not cTnI itself has a direct impact on acute myocardial injury is unknown. To exclude the influence of cTnI antibody on the cardiac infarct size, we studied the effect of cTnI shortly after myocardial ischaemia-reperfusion (I/R) injury when cTnI antibodies were not elevated. Pretreatment with cTnI augmented the myocardial infarct size caused by I/R, accompanied by an increase in inflammatory markers in the blood and myocardium. Additional experiments using human umbilical vein endothelial cells (HUVECs) showed that the detrimental effect of cTnI was related to cTnI-induced increase in vascular cell adhesion molecule-1 (VCAM-1) expression and VCAM-1 mediated adhesion of human monocytes (THP-1) to HUVECs, which could be neutralized by VCAM-1 antibody. Both toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) were involved in the signalling pathway, because blockade of either TLR4 or NF-κB inhibited the cTnI's effect on VCAM-1 expression and adhesion of monocytes to endothelial cells. Moreover, TLR4 inhibition reduced cTnI-augmented cardiac injury in rats with I/R injury. We conclude that cTnI exacerbates myocardial I/R injury by inducing the adhesion of monocytes to vascular endothelial cells via activation of the TLR4/NF-κB pathway. Inhibition of TLR4 may be an alternative strategy to reduce cTnI-induced myocardial I/R injury.

Impact of subclinical coronary artery disease on the clinical outcomes of carotid endarterectomy

OBJECTIVE Controversy persists regarding the optimal management of subclinical coronary artery disease (CAD) prior to carotid endarterectomy (CEA) and the impact of CAD on clinical outcomes after CEA. This study aimed to evaluate the short-term surgical risks and long-term outcomes of patients with subclinical CAD who underwent CEA. METHODS The authors performed a retrospective study of data from a prospective CEA registry. They analyzed a total of 702 cases involving patients without a history of CAD who received preoperative cardiac risk assessment by radionuclide myocardial perfusion imaging (MPI) and underwent CEA over a 10-year period. The management strategy (the necessity, sequence, and treatment modality of coronary revascularization and optimal perioperative medical treatment) was determined according to the presence, severity, and extent of CAD as determined by preoperative MPI and additional coronary computed tomography angiography and/or coronary angiography. Perioperative cardiac damage was defined on the basis of postoperative elevation of the blood level of cardiac troponin I (0.05-0.5 ng/ml) in the absence of myocardial ischemia. The primary endpoint was the composite of any stroke, myocardial infarction, or death during the perioperative period and all-cause mortality within 4 years of CEA. The associations between clinical outcomes after CEA and subclinical CAD were analyzed. RESULTS Concomitant subclinical CAD was observed in 81 patients (11.5%). These patients did have a higher incidence of perioperative cardiac damage (13.6% vs 0.5%, p < 0.01), but they had similar primary endpoint incidences during the perioperative period (2.5% vs.1.8%, p = 0.65) and similar estimated 4-year primary endpoint rates (13.6% vs 12.4%, p = 0.76) as the patients without subclinical CAD. Kaplan-Meier survival analysis showed that the 2 groups had similar rates of overall survival (p = 0.75). CONCLUSIONS Patients with subclinical CAD can undergo CEA with acceptable short- and long-term outcomes provided they receive selective coronary revascularization and optimal perioperative medical treatment.

Evaluation of the Methods and Management of Acute Coronary Events (EMMACE)-3: protocol for a longitudinal study

INTRODUCTION

Patients with cardiovascular disease are living longer and are more frequently accessing healthcare resources. The Evaluation of the Methods and Management of Acute Coronary Events (EMMACE)-3 national study is designed to improve understanding of the effect of quality of care on health-related outcomes for patients hospitalised with acute coronary syndrome (ACS).

METHODS AND ANALYSIS

EMMACE-3 is a longitudinal study of 5556 patients hospitalised with an ACS in England. The study collects repeated measures of health-related quality of life, information about medications and patient adherence profiles, a survey of hospital facilities, and morbidity and mortality data from linkages to multiple electronic health records. Together with EMMACE-3X and EMMACE-4, EMMACE-3 will assimilate detailed information for about 13 000 patients across more than 60 hospitals in England.

ETHICS AND DISSEMINATION

EMMACE-3 was given a favourable ethical opinion by Leeds (West) Research Ethics committee (REC reference: 10/H131374). On successful application, study data will be shared with academic collaborators. The findings from EMMACE-3 will be disseminated through peer-reviewed publications, at scientific conferences, the media, and through patient and public involvement.

STUDY REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT01808027. Information about the study is also available at EMMACE.org.

Molecular basis of cardioprotective effect of antioxidant vitamins in myocardial infarction

Acute myocardial infarction (AMI) is the leading cause of mortality worldwide. Major advances in the treatment of acute coronary syndromes and myocardial infarction, using cardiologic interventions, such as thrombolysis or percutaneous coronary angioplasty (PCA) have improved the clinical outcome of patients. Nevertheless, as a consequence of these procedures, the ischemic zone is reperfused, giving rise to a lethal reperfusion event accompanied by increased production of reactive oxygen species (oxidative stress). These reactive species attack biomolecules such as lipids, DNA, and proteins enhancing the previously established tissue damage, as well as triggering cell death pathways. Studies on animal models of AMI suggest that lethal reperfusion accounts for up to 50% of the final size of a myocardial infarct, a part of the damage likely to be prevented. Although a number of strategies have been aimed at to ameliorate lethal reperfusion injury, up to date the beneficial effects in clinical settings have been disappointing. The use of antioxidant vitamins could be a suitable strategy with this purpose. In this review, we propose a systematic approach to the molecular basis of the cardioprotective effect of antioxidant vitamins in myocardial ischemia-reperfusion injury that could offer a novel therapeutic opportunity against this oxidative tissue damage.

Cardioprotection against ischaemia/reperfusion by vitamins C and E plus n-3 fatty acids: molecular mechanisms and potential clinical applications

The role of oxidative stress in ischaemic heart disease has been thoroughly investigated in humans. Increased levels of ROS (reactive oxygen species) and RNS (reactive nitrogen species) have been demonstrated during ischaemia and post-ischaemic reperfusion in humans. Depending on their concentrations, these reactive species can act either as benevolent molecules that promote cell survival (at low-to-moderate concentrations) or can induce irreversible cellular damage and death (at high concentrations). Although high ROS levels can induce NF-κB (nuclear factor κB) activation, inflammation, apoptosis or necrosis, low-to-moderate levels can enhance the antioxidant response, via Nrf2 (nuclear factor-erythroid 2-related factor 2) activation. However, a clear definition of these concentration thresholds remains to be established. Although a number of experimental studies have demonstrated that oxidative stress plays a major role in heart ischaemia/reperfusion pathophysiology, controlled clinical trials have failed to prove the efficacy of antioxidants in acute or long-term treatments of ischaemic heart disease. Oral doses of vitamin C are not sufficient to promote ROS scavenging and only down-regulate their production via NADPH oxidase, a biological effect shared by vitamin E to abrogate oxidative stress. However, infusion of vitamin C at doses high enough to achieve plasma levels of 10 mmol/l should prevent superoxide production and the pathophysiological cascade of deleterious heart effects. In turn, n-3 PUFA (polyunsaturated fatty acid) exposure leads to enhanced activity of antioxidant enzymes. In the present review, we present evidence to support the molecular basis for a novel pharmacological strategy using these antioxidant vitamins plus n-3 PUFAs for cardioprotection in clinical settings, such as post-operative atrial fibrillation, percutaneous coronary intervention following acute myocardial infarction and other events that are associated with ischaemia/reperfusion.

Acute coronary syndromes: an old age problem

The increasing population in older age will lead to greater numbers of them presenting with acute coronary syndromes (ACS). This has implications on global healthcare resources and necessitates better management and selection for evidenced-based therapies. The elderly are a high risk group with more significant treatment benefits than younger ACS. Nevertheless, age related inequalities in ACS care are recognised and persist. This discrepancy in care, to some extent, is explained by the higher frequency of atypical and delayed presentations in the elderly, and less diagnostic electrocardiograms at presentation, potentiating a delay in ACS diagnosis. Under estimation of mortality risk in the elderly due to limited consideration for physiological frailty, co-morbidity, cognitive/psychological impairment and physical disability, less input by cardiology specialists and lack of randomised, controlled trials data to guide management in the elderly may further confound the inequality of care. While these inequalities exist, there remains a substantial opportunity to improve age related ACS outcomes. The selection of elderly patients for specific therapies and medication regimens are unanswered. There is a growing need for randomised, controlled trial data to be more representative of the population and enroll those of advanced age with co-morbidity. A lack of reporting of adverse events, such as renal impairment post coronary angiography, in the elderly further limit risk benefit decisions. Substantial improvements in care of elderly ACS patients are required and should be advocated. Ultimately, these improvements are likely to lead to better outcomes post ACS. However, the improvement in outcome is not infinite and will be limited by non-modifiable factors of age-related risk.

Prevention of postoperative atrial fibrillation: novel and safe strategy based on the modulation of the antioxidant system

Postoperative atrial fibrillation (AF) is the most common arrhythmia following cardiac surgery with extracorporeal circulation. The pathogenesis of postoperative AF is multifactorial. Oxidative stress, caused by the unavoidable ischemia-reperfusion event occurring in this setting, is a major contributory factor. Reactive oxygen species (ROS)-derived effects could result in lipid peroxidation, protein carbonylation, or DNA oxidation of cardiac tissue, thus leading to functional and structural myocardial remodeling. The vulnerability of myocardial tissue to the oxidative challenge is also dependent on the activity of the antioxidant system. High ROS levels, overwhelming this system, should result in deleterious cellular effects, such as the induction of necrosis, apoptosis, or autophagy. Nevertheless, tissue exposure to low to moderate ROS levels could trigger a survival response with a trend to reinforce the antioxidant defense system. Administration of n-3 polyunsaturated fatty acids (PUFA), known to involve a moderate ROS production, is consistent with a diminished vulnerability to the development of postoperative AF. Accordingly, supplementation of n-3 PUFA successfully reduced the incidence of postoperative AF after coronary bypass grafting. This response is due to an up-regulation of antioxidant enzymes, as shown in experimental models. In turn, non-enzymatic antioxidant reinforcement through vitamin C administration prior to cardiac surgery has also reduced the postoperative AF incidence. Therefore, it should be expected that a mixed therapy result in an improvement of the cardioprotective effect by modulating both components of the antioxidant system. We present novel available evidence supporting the hypothesis of an effective prevention of postoperative AF including a two-step therapeutic strategy: n-3 PUFA followed by vitamin C supplementation to patients scheduled for cardiac surgery with extracorporeal circulation. The present study should encourage the design of clinical trials aimed to test the efficacy of this strategy to offer new therapeutic opportunities to patients challenged by ischemia-reperfusion events not solely in heart, but also in other organs such as kidney or liver in transplantation surgeries.

Association of frontal QRS-T angle--age risk score on admission electrocardiogram with mortality in patients admitted with an acute coronary syndrome

Risk assessment is central to the management of acute coronary syndromes. Often, however, assessment is not complete until the troponin concentration is available. Using 2 multicenter prospective observational studies (Evaluation of Methods and Management of Acute Coronary Events [EMMACE] 2, test cohort, 1,843 patients; and EMMACE-1, validation cohort, 550 patients) of unselected patients with acute coronary syndromes, a point-of-admission risk stratification tool using frontal QRS-T angle derived from automated measurements and age for the prediction of 30-day and 2-year mortality was evaluated. Two-year mortality was lowest in patients with frontal QRS-T angles <38° and highest in patients with frontal QRS-T angles >104° (44.7% vs 14.8%, p <0.001). Increasing frontal QRS-T angle-age risk (FAAR) scores were associated with increasing 30-day and 2-year mortality (for 2-year mortality, score 0 = 3.7%, score 4 = 57%; p <0.001). The FAAR score was a good discriminator of mortality (C statistics 0.74 [95% confidence interval 0.71 to 0.78] at 30 days and 0.77 [95% confidence interval 0.75 to 0.79] at 2 years), maintained its performance in the EMMACE-1 cohort at 30 days (C statistics 0.76 (95% confidence interval 0.71 to 0.8] at 30 days and 0.79 (95% confidence interval 0.75 to 0.83] at 2 years), in men and women, in ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction, and compared favorably with the Global Registry of Acute Coronary Events (GRACE) score. The integrated discrimination improvement (age to FAAR score at 30 days and at 2 years in EMMACE-1 and EMMACE-2) was p <0.001. In conclusion, the FAAR score is a point-of-admission risk tool that predicts 30-day and 2-year mortality from 2 variables across a spectrum of patients with acute coronary syndromes. It does not require the results of biomarker assays or rely on the subjective interpretation of electrocardiograms.