Association of ST-elevation and non-ST-elevation presentation on ECG with transmurality and size of myocardial infarction as assessed by contrast-enhanced magnetic resonance imaging

Atherosclerotic Plaque Erosion: Mechanisms, Clinical Implications, and Potential Therapeutic Strategies-A Review

ABSTRACT

Atherosclerosis is an insidious and progressive inflammatory disease characterized by the formation of lipid-laden plaques within the intima of arterial walls with potentially devastating consequences. While rupture of vulnerable plaques has been extensively studied, a distinct mechanism known as plaque erosion (PE) has gained recognition and attention in recent years. PE, characterized by the loss of endothelial cell lining in the presence of intact fibrous cap, contributes to a significant and growing proportion of acute coronary events. However, despite a heterogeneous substrate underlying coronary thrombosis, treatment remains identical. This article provides an overview of atherosclerotic PE characteristics and its underlying mechanisms, highlights its clinical implications, and discusses potential therapeutic strategies.

Acute Coronary Syndrome Subphenotypes Based on Repeated Biomarker Measurements in Relation to Long-Term Mortality Risk

BACKGROUND

We aimed to identify patients with subphenotypes of postacute coronary syndrome (ACS) using repeated measurements of high-sensitivity cardiac troponin T, N-terminal pro-B-type natriuretic peptide, high-sensitivity C-reactive protein, and growth differentiation factor 15 in the year after the index admission, and to investigate their association with long-term mortality risk.

METHODS AND RESULTS

BIOMArCS (BIOMarker Study to Identify the Acute Risk of a Coronary Syndrome) was an observational study of patients with ACS, who underwent high-frequency blood sampling for 1 year. Biomarkers were measured in a median of 16 repeated samples per individual. Cluster analysis was performed to identify biomarker-based subphenotypes in 723 patients without a repeat ACS in the first year. Patients with a repeat ACS (N=36) were considered a separate cluster. Differences in all-cause death were evaluated using accelerated failure time models (median follow-up, 9.1 years; 141 deaths). Three biomarker-based clusters were identified: cluster 1 showed low and stable biomarker concentrations, cluster 2 had elevated concentrations that subsequently decreased, and cluster 3 showed persistently elevated concentrations. The temporal biomarker patterns of patients in cluster 3 were similar to those with a repeat ACS during the first year. Clusters 1 and 2 had a similar and favorable long-term mortality risk. Cluster 3 had the highest mortality risk. The adjusted survival time ratio was 0.64 (95% CI, 0.44-0.93; P=0.018) compared with cluster 1, and 0.71 (95% CI, 0.39-1.32; P=0.281) compared with patients with a repeat ACS.

CONCLUSIONS

Patients with subphenotypes of post-ACS with different all-cause mortality risks during long-term follow-up can be identified on the basis of repeatedly measured cardiovascular biomarkers. Patients with persistently elevated biomarkers have the worst outcomes, regardless of whether they experienced a repeat ACS in the first year.

Myocardial infarction and physical function: the REasons for Geographic And Racial Differences in Stroke prospective cohort study

Objective

To examine associations between myocardial infarction (MI) and multiple physical function metrics.

Methods

Among participants aged ≥45 years in the REasons for Geographic And Racial Differences in Stroke prospective cohort study, instrumental activities of daily living (IADL), activities of daily living (ADL), gait speed, chair stands, and Short Form-12 physical component summary (PCS) were assessed after approximately 10 years of follow-up. We examined associations between MI and physical function (no MI [n = 9,472], adjudicated MI during follow-up [n = 288, median 4.7 years prior to function assessment], history of MI at baseline [n = 745], history of MI at baseline and adjudicated MI during follow-up [n = 70, median of 6.7 years prior to function assessment]). Models were adjusted for sociodemographic characteristics, health behaviours, depressive symptoms, cognitive impairment, body mass index, diabetes, hypertension, and urinary albumin to creatinine ratio. We examined subgroups defined by age, gender, and race.

Results

The average age at baseline was 62 years old, 56% were women, and 35% Black. MI was significantly associated with worse IADL and ADL scores, IADL dependency, chair stands, and PCS, but not ADL dependency or gait speed. For example, compared to participants without MI, IADL scores (possible range 0-14, higher score represents worse function) were greater for participants with MI during follow-up (difference: 0.37 [95% CI 0.16, 0.59]), MI at baseline (0.26 [95% CI 0.12, 0.41]), and MI at baseline and follow-up (0.71 [95% CI 0.15, 1.26]), p < 0.001. Associations tended to be greater in magnitude among participants who were women and particularly Black women.

Conclusion

MI was associated with various measures of physical function. These decrements in function associated with MI may be preventable or treatable.

Biomarker Concentrations and Their Temporal Changes in Patients With Myocardial Infarction and Nonobstructive Compared With Obstructive Coronary Arteries: Results From the PLATO Trial

Background The pathobiology of myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) is often uncertain. Investigating biomarker concentrations and their changes may offer novel pathophysiological insights. Methods and Results In this post hoc study of the PLATO (Platelet Inhibition and Patient Outcomes) trial, concentrations of hs-cTnT (high-sensitivity cardiac troponin T), NT-proBNP (N-terminal pro-B-type natriuretic peptide), hs-CRP (high-sensitivity C-reactive protein), and GDF-15 (growth differentiation factor 15) were measured in patients with MINOCA at baseline (n=554) and at 1-month follow-up (n=107). For comparisons, biomarkers were also measured in patients with MI with obstructive (stenosis ≥50%) coronary artery disease (baseline: n=11 106; follow-up: n=2755]). Adjusted linear regression models were used to compare concentrations and their short- and long-term changes. The adjusted geometric mean ratios (GMRs) in patients with MINOCA (median age, 61 years; 50.4% women) indicated lower hs-cTnT (GMR, 0.77 [95% CI, 0.68-0.88]) but higher hs-CRP (GMR, 1.21 [95% CI, 1.08-1.37]) and GDF-15 concentrations (GMR, 1.06 [95% CI, 1.02-1.11]) at baseline compared with patients with MI with obstructive coronary artery disease, whereas NT-proBNP concentrations were similar. Temporal decreases in hs-cTnT, NT-proBNP, and hs-CRP concentrations until 1-month follow-up were more pronounced in patients with MINOCA. At follow-up, patients with MINOCA had lower concentrations of hs-cTnT (GMR, 0.71 [95% CI, 0.60-0.84]), NT-proBNP (GMR, 0.45 [95% CI, 0.36-0.56]), and hs-CRP (GMR, 0.68 [95% CI, 0.53-0.86]). One-month GDF-15 concentrations were similar between both groups with MI. Conclusions Biomarker concentrations suggest greater initial inflammatory activity, similar degree of myocardial dysfunction, and less pronounced myocardial injury during the acute phase of MINOCA compared with MI with obstructive coronary artery disease but also faster myocardial recovery. Registration URL: http://www.clinicaltrials.gov; Unique identifier: NCT00391872.

A case report of rescue of a patient with a left ventricular free wall rupture associated with a small subtle ST-elevation myocardial infarction

Background

Left ventricular (LV) free wall ruptures (LVFWRs) of myocardial infarctions (MIs) are still one of the most fatal mechanical complications after an acute MI (AMI). LVFWRs are estimated to occur in 0.01% to 0.52% of patients following an ST-elevation MI (STEMI) and are rarely reported in the setting of a non- or subtle-ST-elevation MI.

Case summary

We herein present a report of a 92-year-old male rescue case with an LVFWR following a small subtle-STEMI. Contrast cardiac computed tomography was useful to diagnose the LVFWR. An emergent cardiac surgery was performed. Finally, the patient’s life was saved.

Discussion

This case demonstrates that even without clinical evidence of transmural infarction such as non- or subtle-STEMI, those patients may carry a risk of fatal complications including LVFWR, especially in older age and a first lateral wall AMI without collateral flow, as in this present case. Thus, the physicians should be aware of the possibility of LVFWRs even in the setting of an AMI without or with subtle-ST-elevation. High clinical suspicion and vigilance are the cornerstones of a timely and accurate diagnosis of LVFWR. This is the first report of a rescue case of a patient with an LVFWR associated with a subtle-STEMI.

Differences in biomarker concentrations and predictions of long-term outcome in patients with ST-elevation and non-ST-elevation myocardial infarction

BACKGROUND

Differences in biomarkers reflective of pathobiology and prognosis between ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) are incompletely understood and may offer insights for tailoring of treatment.

METHODS

This registry-based study included 538 STEMI and 544 NSTEMI patients admitted 2008-2014. Blood samples were collected day 1-3 after admission and 175 biomarkers were analyzed using Proximity Extension Assay and Multiple Reaction Monitoring mass spectrometry. Adjusted Lasso analysis (penalized logistic regression model) was used to select biomarkers that discriminated STEMI from NSTEMI patients. Biomarkers identified by the Lasso analysis were then evaluated in adjusted Cox regressions for associations with death or major adverse cardiovascular events.

RESULTS

Biomarkers strongly discriminated STEMI and NSTEMI when considered simultaneously in adjusted Lasso analysis (c-statistic 0.764). Eleven biomarkers independently discriminated STEMI and NSTEMI; seven showing higher concentrations in STEMI: myoglobin, N-terminal pro-B-type natriuretic peptide, serum amyloid A-1 and A-2 protein, ST2 protein, interleukin-6 and chitinase-3-like protein 1; and four showing higher concentrations in NSTEMI: fibroblast growth factor 23, membrane-bound aminopeptidase P, tumor necrosis factor-related activation-induced cytokine and apolipoprotein C-I. During up to 6.6 years of prognostic follow-up, none of these biomarkers exhibited different associations with adverse outcome between STEMI and NSTEMI.

CONCLUSIONS

In the acute setting, biomarkers indicated greater myocardial dysfunction and inflammation in STEMI, whereas they displayed a more diverse pathophysiologic pattern in NSTEMI patients. These biomarkers were similarly prognostic in STEMI and NSTEMI patients. The results do not support treating STEMI and NSTEMI patients differently based on the concentrations of these biomarkers.

Non-ST-segment elevation myocardial infarction with evidence of transmural infarction complicated by left ventricular rupture during percutaneous coronary intervention

We report a case of a 68-year-old man presenting with a non-ST-segment elevation myocardial infarction, complicated by fatal left ventricular free wall rupture with electromechanical disassociation and cardiac tamponade during percutaneous coronary intervention. The aetiology for the sudden haemodynamic collapse was initially unclear; however, transthoracic echocardiography confirmed pericardial tamponade and postmortem revealed complete transmural myocardial infarction with left ventricular free wall rupture. This serves as an important lesson that transmural infarction and subsequent mechanical complications, including ventricular rupture, can occur in non-ST-segment myocardial infarction and not just ST-segment myocardial infarction.

Transmural Extent in Relation to Clinical Scoring in Non-ST Elevation Myocardial Infarction Patients: Speckle-Tracking Echocardiographic Study

Background:

To assess the extent of transmurality in non-ST elevation myocardial infarction (NSTEMI) patients using speckle-tracking echocardiography (STE) in relation to their risk categorization to improve the risk stratification of NSTEMI patients through detecting the presence of transmural infarction.

Patients and Methods:

It included 96 patients with NSTEMI. All patients were subjected to GRACE score (GS) calculation, transthoracic and speckle-tracking echocardiography (STE): To detect left ventricular ejection fraction and myocardial global longitudinal strain [GLS] and circumferential strain [CS].

Results:

As compared to low-GS group; high-risk group was older with the increased prevalence of hypertension (HTN), diabetes, and smoking. There was no significant difference between both groups regarding LS and CS of all 17 segments except for apex where longitudinal strain (LS) was significantly decreased in low-risk group (−17.2 ± 1.1) as compared to high-risk group (−18.6 ± 1.4). GLS was significantly decreased in high-risk group (15.4 ± 0.6) as compared to low-risk group (16 ± 0.8), P = 0.02 with no significant difference in the global CS (P = 0.8). Transmural infarction constitutes 37.5% of all patients. The prevalence of transmural infarction was increased in the low-risk group without significant difference. GS showed a positive correlation with age, male, HTN, diabetes, and smoking and negative correlation with GLS. There was no significant correlation between GS and global CS. Age, GS, and LS were significantly related to transmural infarction. None was found to predict the occurrence of transmural infarction.

Conclusion:

Transmural extent as detected by STE had been found in a relatively substantial number of patients with NSTEMI, and it may serve as a tool in conjunction with risk stratification scores for the selection of high-risk patients.

Different Statin Effects of ST-elevation Versus Non-ST-Elevation Acute Myocardial Infarction After Stent Implantation

BACKGROUND

Intensive statin therapy reduces cardiovascular events in acute coronary syndrome. The data concerning the long-term clinical impacts of statin therapy between ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) after drug-eluting stent implantation are limited. We compared the 2-year clinical outcomes between these 2 groups after statin therapy.

MATERIALS AND METHODS

A total of 30,616 Korean patients with acute myocardial infarction (AMI) were enrolled. Among them, 13,686 patients were classified as group A (STEMI statin user), 3,824 patients were as group B (STEMI statin nonuser), 10,398 patients were as group C (NSTEMI statin user), and 2,708 patients were as group D (NSTEMI statin nonuser). The major clinical endpoint was the occurrence of major adverse cardiac events (MACE) defined as all-cause death, recurrent myocardial infarction (re-MI), and any repeat revascularization during a 2-year follow-up period.

RESULTS

After adjustment, the cumulative risks of MACE (adjusted hazard ratio [aHR] = 1.112 [1.002-1.235]; P = 0.047), all-cause death (aHR = 1.271 [1.054-1.532]; P = 0.012), and target vessel revascularization (TVR, aHR = 1.262 [1.049-1.518]; P = 0.014) in group C were significantly higher than group A. The cumulative risks of MACE, all-cause death, and cardiac death of the statin nonuser group (groups B and D) were significantly higher compared with statin user group (groups A and C).

CONCLUSIONS

Statin therapy was more effective in reducing the cumulative risks of MACE, all-cause death, and TVR in the STEMI group than NSTEMI group in Korean patients with AMI after successful drug-eluting stent implantation.

Cardiac MR Imaging in Acute Coronary Syndrome: Application and Image Interpretation

Acute coronary syndrome (ACS) is a frequent cause of hospitalization and coronary interventions. Cardiac magnetic resonance (MR) imaging is an increasingly used technique for initial work-up of chest pain and early post-reperfusion and follow-up evaluation of ACS to identify patients at high risk of further cardiac events. Cardiac MR imaging can evaluate with accuracy a variety of prognostic indicators of myocardial damage, including regional myocardial dysfunction, infarct distribution, infarct size, myocardium at risk, microvascular obstruction, and intramyocardial hemorrhage in both acute setting and later follow-up examinations. In addition, MR imaging is useful to rule out other causes of acute chest pain in patients admitted to the emergency department. In this article, a brief explanation of the pathophysiology, classification, and treatment options for patients with ACS will be introduced. Indications of cardiac MR imaging in ACS patients will be reviewed and specific cardiac MR protocol, image interpretation, and potential diagnostic pitfalls will be discussed. ^© RSNA, 2017 Online supplemental material is available for this article.

Genetic Variants on Chromosome 1p13.3 Are Associated with Non-ST Elevation Myocardial Infarction and the Expression of DRAM2 in the Finnish Population

Myocardial infarction (MI) is divided into either ST elevation MI (STEMI) or non-ST elevation MI (NSTEMI), differing in a number of clinical characteristics. We sought to identify genetic variants conferring risk to NSTEMI or STEMI by conducting a genome-wide association study (GWAS) of MI stratified into NSTEMI and STEMI in a consecutive sample of 1,579 acute MI cases with 1,576 controls. Subsequently, we followed the results in an independent population-based sample of 562 cases and 566 controls, a partially independent prospective cohort (N = 16,627 with 163 incident NSTEMI cases), and examined the effect of disease-associated variants on gene expression in 513 healthy participants. Genetic variants on chromosome 1p13.3 near the damage-regulated autophagy modulator 2 gene DRAM2 associated with NSTEMI (rs656843; odds ratio 1.57, P = 3.11 × 10⁻¹⁰) in the case-control analysis with a consistent but not statistically significant effect in the prospective cohort (rs656843; hazard ratio 1.13, P = 0.43). These variants were not associated with STEMI (rs656843; odds ratio, 1.11, P = 0.20; hazard ratio 0.97, P = 0.87), appearing to have a pronounced effect on NSTEMI risk. A majority of the variants at 1p13.3 associated with NSTEMI were also associated with the expression level of DRAM2 in blood leukocytes of healthy controls (top-ranked variant rs325927, P = 1.50 × 10⁻¹²). The results suggest that genetic factors may in part influence whether coronary artery disease results in NSTEMI rather than STEMI.

The history, hotspots, and trends of electrocardiogram

The electrocardiogram (ECG) has broad applications in clinical diagnosis and prognosis of cardiovascular disease. Many researchers have contributed to its progressive development. To commemorate those pioneers, and to better study and promote the use of ECG, we reviewed and present here a systematic introduction about the history, hotspots, and trends of ECG. In the historical part, information including the invention, improvement, and extensive applications of ECG, such as in long QT syndrome (LQTS), angina, and myocardial infarction (MI), are chronologically presented. New technologies and applications from the 1990s are also introduced. In the second part, we use the bibliometric analysis method to analyze the hotspots in the field of ECG-related research. By using total citations and year-specific total citations as our main criteria, four key hotspots in ECG-related research were identified from 11 articles, including atrial fibrillation, LQTS, angina and MI, and heart rate variability. Recent studies in those four areas are also reported. In the final part, we discuss the future trends concerning ECG-related research. The authors believe that improvement of the ECG instrumentation, big data mining for ECG, and the accuracy of diagnosis and application will be areas of continuous concern.

Process optimization in the emergency department by the use of point-of-care-testing (POCT) in life-threatening conditions: comparative best practice examples from Germany and Malta

PURPOSE

Point-of-care testing (POCT) at the Emergency Department (ED) attains better objectives in patient care while aiming to achieve early diagnosis for faster medical decision-making. This study assesses and compares the benefits of POCT in the ED in Germany and Malta, while considering differences in their health systems.

METHODOLOGY/APPROACH

This chapter utilizes multiple case study approach using Six Sigma. The German case study assesses the use of POCT in acute coronary syndrome patients, compared to the central lab setting. The Maltese case study is a pilot study of the use of medical ultrasonography as a POCT to detect abdominal free fluid in post-blunt trauma.

FINDINGS

This study provides clear examples of the effectiveness of POCT in life-threatening conditions, as compared to the use of traditional central lab or the medical imaging department. Therapeutic quality in the ED and patient outcomes directly depend upon turnaround time, particularly for life-threatening conditions. Faster turnaround time not only saves lives but reduces morbidity, which in the long-term is a critical cost driver for hospitals.

ORIGINALITY/VALUE

The application of Six Sigma and the international comparison of POCT as best practice for life-threatening conditions in the ED.

Role of the ECG in initial acute coronary syndrome triage: primary PCI regardless presence of ST elevation or of non-ST elevation

The major initial triaging decision in acute coronary syndrome (ACS) is whether or not percutaneous coronary intervention (PCI) is the primary treatment. Current guidelines recommend primary PCI in ST-elevation ACS (STEACS) and initial antithrombotic therapy in non-ST-elevation ACS (NSTEACS). This review probes the question whether this decision can indeed be based on the ECG. Genesis of STE/NSTE ECGs depends on the coronary anatomy, collateral circulation and site of the culprit lesion. Other causes than ischaemia may also result in ST-segment changes. It has been demonstrated that the area at risk cannot reliably be estimated by the magnitude of the ST change, that complete as well as incomplete occlusions can cause STE as well as NSTE ECGs, and that STE and NSTE patterns cannot differentiate between transmural and non-transmural ischaemia. Furthermore, unstable angina can occur with STE and NSTE ECGs. We conclude that the ECG can be used to assist in detecting ischaemia, but that electrocardiographic STE and NSTE patterns are not uniquely related to distinctly different pathophysiological mechanisms. Hence, in ACS, primary PCI might be considered regardless of the nature of the ST deviation, and it should be done with the shortest possible delay, because ‘time is muscle’.

ECG signs of acute myocardial ischemia in the prehospital setting of a suspected acute coronary syndrome and its association with outcomes

AIMS

The aims of this study were (a) to determine the prehospital prevalence of electrocardiographic (ECG) signs of acute myocardial ischemia in patients with suspected acute coronary syndrome and (b) to describe the relationships between the various ECG patterns and the diagnosis of acute myocardial infarction (AMI) and outcomes.

METHODS

Prospective cohort study using data from an interventional trial in acute chest pain patients transported by the emergency medical services. These patients were classified into 3 groups: patients with ECG showing signs of acute myocardial ischemia, patients with ECG showing other abnormal changes (bundle-branch block, pacemaker rhythm, Q-wave or T-wave inversion) and patients without significant pathologic findings. All P values are age-adjusted.

RESULTS

Among 1546 patients, 312 (20%) had ECG signs of acute myocardial ischemia. Of them, 57% had a final diagnosis of AMI versus 26% of those with other abnormal ECGs and 12% of those with ECG without significant pathologic findings (P<.0001). In all, 53% of all AMI cases involved patients without ECG signs of acute myocardial ischemia. Although ECG signs of acute myocardial ischemia predicted heart failure and ventricular tachyarrhythmias both prior to and after hospital admission, there was no significant difference in 30-day mortality between the 3 patient groups (4.3%, 3.7%, and 1.2%, respectively, P=.11).

CONCLUSION

Among patients with a clinical suspicion of AMI in the prehospital setting, the prevalence of ECG signs suggesting AMI was low, as was the ability to identify AMI patients using ECG findings only. We therefore need better instruments in the prehospital triage of patients with acute chest pain.