The clinical approach to diagnosing peri-procedural myocardial infarction after percutaneous coronary interventions according to the fourth universal definition of myocardial infarction - from the study group on biomarkers of the European Society of Cardiology (ESC) Association for Acute CardioVascular Care (ACVC)

PURPOSE

This review intends to illustrate basic principles on how to apply the Fourth Universal Definition of Myocardial Infarction (UDMI) for the diagnosis of peri-procedural myocardial infarction (MI) after percutaneous coronary interventions (PCI) in clinical practice.

METHODS AND RESULTS

Review of routine case-based events. Increases in cardiac troponin (cTn) concentrations are common after elective PCI in patients with chronic coronary syndrome (CCS). Peri-procedural PCI-related MI (type 4a MI) in CCS patients should be diagnosed in cases of major peri-procedural acute myocardial injury indicated by an increase in cTn concentrations of >5-times the 99th percentile upper reference limit (URL) together with evidence of new peri-procedural myocardial ischaemia as demonstrated by electrocardiography (ECG), imaging, or flow-limiting peri-procedural complications in coronary angiography. Measurement of cTn baseline concentrations before elective PCI is useful. In patients presenting with acute MI undergoing PCI, peri-procedural increases in cTn concentrations are usually due to their index presentation and not PCI-related, apart from obvious major peri-procedural complications, such as persistent occlusion of a large side branch or no-reflow after stent implantation.

CONCLUSION

The distinction between type 4a MI, PCI-related acute myocardial injury, and chronic myocardial injury can be challenging in individuals undergoing PCI. Careful integration of all available clinical data is essential for correct classification.

Prognostically relevant periprocedural myocardial injury and infarction associated with percutaneous coronary interventions: a Consensus Document of the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

A substantial number of chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI) experience periprocedural myocardial injury or infarction. Accurate diagnosis of these PCI-related complications is required to guide further management given that their occurrence may be associated with increased risk of major adverse cardiac events (MACE). Due to lack of scientific data, the cut-off thresholds of post-PCI cardiac troponin (cTn) elevation used for defining periprocedural myocardial injury and infarction, have been selected based on expert consensus opinions, and their prognostic relevance remains unclear. In this Consensus Document from the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI), we recommend, whenever possible, the measurement of baseline (pre-PCI) cTn and post-PCI cTn values in all CCS patients undergoing PCI. We confirm the prognostic relevance of the post-PCI cTn elevation >5× 99th percentile URL threshold used to define type 4a myocardial infarction (MI). In the absence of periprocedural angiographic flow-limiting complications or electrocardiogram (ECG) and imaging evidence of new myocardial ischaemia, we propose the same post-PCI cTn cut-off threshold (>5× 99th percentile URL) be used to define prognostically relevant ‘major’ periprocedural myocardial injury. As both type 4a MI and major periprocedural myocardial injury are strong independent predictors of all-cause mortality at 1 year post-PCI, they may be used as quality metrics and surrogate endpoints for clinical trials. Further research is needed to evaluate treatment strategies for reducing the risk of major periprocedural myocardial injury, type 4a MI, and MACE in CCS patients undergoing PCI.

Cardiovascular biomarkers in patients with COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has increased awareness that severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2) may have profound effects on the cardiovascular system. COVID-19 often affects patients with pre-existing cardiac disease, and may trigger acute respiratory distress syndrome (ARDS), venous thromboembolism (VTE), acute myocardial infarction (AMI), and acute heart failure (AHF). However, as COVID-19 is primarily a respiratory infectious disease, there remain substantial uncertainty and controversy whether and how cardiovascular biomarkers should be used in patients with suspected COVID-19. To help clinicians understand the possible value as well as the most appropriate interpretation of cardiovascular biomarkers in COVID-19, it is important to highlight that recent findings regarding the prognostic role of cardiovascular biomarkers in patients hospitalized with COVID-19 are similar to those obtained in studies for pneumonia and ARDS in general. Cardiovascular biomarkers reflecting pathophysiological processes involved in COVID-19/pneumonia and its complications have a role evaluating disease severity, cardiac involvement, and risk of death in COVID-19 as well as in pneumonias caused by other pathogens. First, cardiomyocyte injury, as quantified by cardiac troponin concentrations, and haemodynamic cardiac stress, as quantified by natriuretic peptide concentrations, may occur in COVID-19 as in other pneumonias. The level of those biomarkers correlates with disease severity and mortality. Interpretation of cardiac troponin and natriuretic peptide concentrations as quantitative variables may aid in risk stratification in COVID-19/pneumonia and also will ensure that these biomarkers maintain high diagnostic accuracy for AMI and AHF. Second, activated coagulation as quantified by D-dimers seems more prominent in COVID-19 as in other pneumonias. Due to the central role of endothelitis and VTE in COVID-19, serial measurements of D-dimers may help physicians in the selection of patients for VTE imaging and the intensification of the level of anticoagulation from prophylactic to slightly higher or even therapeutic doses.

Procedural myocardial injury, infarction and mortality in patients undergoing elective PCI: a pooled analysis of patient-level data

AIMS

The prognostic importance of cardiac procedural myocardial injury and myocardial infarction (MI) in chronic coronary syndrome (CCS) patients undergoing elective percutaneous coronary intervention (PCI) is still debated.

METHODS AND RESULTS

We analysed individual data of 9081 patients undergoing elective PCI with normal pre-PCI baseline cardiac troponin (cTn) levels. Multivariate models evaluated the association between post-PCI elevations in cTn and 1-year mortality, while an interval analysis evaluated the impact of the size of the myocardial injury on mortality. Our analysis was performed in the overall population and also according to the type of cTn used [52.0% had high-sensitivity cTn (hs-cTn)]. Procedural myocardial injury, as defined by the Fourth Universal Definition of MI (UDMI) [post-PCI cTn elevation ≥1 × 99th percentile upper reference limit (URL)], occurred in 52.8% of patients and was not associated with 1-year mortality [adj odds ratio (OR), 1.35, 95% confidence interval (CI) (0.84-1.77), P = 0.21]. The association between post-PCI cTn elevation and 1-year mortality was significant starting ≥3 × 99th percentile URL. Major myocardial injury defined by post-PCI ≥5 × 99th percentile URL occurred in 18.2% of patients and was associated with a two-fold increase in the adjusted odds of 1-year mortality [2.29, 95% CI (1.32-3.97), P = 0.004]. In the subset of patients for whom periprocedural evidence of ischaemia was collected (n = 2316), Type 4a MI defined by the Fourth UDMI occurred in 12.7% of patients and was strongly associated with 1-year mortality [adj OR 3.21, 95% CI (1.42-7.27), P = 0.005]. We also present our results according to the type of troponin used (hs-cTn or conventional troponin).

CONCLUSION

Our analysis has demonstrated that in CCS patients with normal baseline cTn levels, the post-PCI cTn elevation of ≥5 × 99th percentile URL used to define Type 4a MI is associated with 1-year mortality and could be used to detect 'major' procedural myocardial injury in the absence of procedural complications or evidence of new myocardial ischaemia.

Cardiac procedural myocardial injury, infarction and mortality in patients undergoing elective PCI: a pooled analysis of patient-level data

Background

The prognostic implications of cardiac procedural myocardial injury and infarction (MI) in chronic coronary syndrome patients undergoing elective percutaneous coronary intervention (PCI) is still debated.

Objective

To determine the optimal cardiac troponin threshold for identifying prognostically important events.

Methods

Using a pooled dataset of nine registries and one randomized trial, we analysed individual data of 14,433 patients undergoing elective PCI with a normal or moderately elevated baseline pre-PCI cardiac troponin (cTn). A multivariate model was performed to evaluate the associations between post-PCI cTn elevation and 1-year mortality after PCI, including thresholds used by existing procedural myocardial injury definitions (Fourth Universal Definition of MI [UDMI] and Academic Research Consortium 2 [ARC-2] / Society for Cardiovascular Angiography and Interventions (SCAI)). The association between type 4a MI and 1-year mortality was also evaluated.

Results

Procedural myocardial injury defined by the Fourth UDMI occurred in 52.5% of patients and was not associated with 1-year mortality (adjOR 1.27, 95% CI [0.90–1.81] p=0.18). The association between post-PCI cTn elevation and 1-year mortality was significant above a 3-fold increase above the upper reference limit, and was optimal for a 5.2-fold increase which corresponded to an 18.3% rate of event, and an adjOR of 2.03 (95% CI [1.31–3.14], p=0.002) (figure). Procedural myocardial injury defined by the ARC-2/SCAI definition occurred in 1.3% of the patients, had a strong association with 1-year mortality (adjOR 4.15, 95% CI [1.62–10.64], p<0.01) but lacked sensitivity (5.2% sensitivity). Type 4a MI occurred in 12.7% of patients, was strongly associated with 1-year mortality (adjOR 3.18, 95% CI [1.47–6.90], p=0.002), but could only be evaluated in a subset of patients (n=3 084) with available data on new myocardial ischaemia post-PCI.

Conclusions

We have demonstrated that a post-PCI cTn elevation ≥5x the 99th percentile URL in CCS patients with normal baseline cTn, represents the optimal threshold for defining prognostically important or “Major” procedural myocardial injury in the absence of evidence for new myocardial ischaemia. Major procedure related myocardial injury and type 4a MI should be considered as a quality metric and endpoints in clinical trials.

Adjusted OR of mortality at 1 year

Funding Acknowledgement

Type of funding source: None

Biomarkers of coagulation and fibrinolysis in acute myocardial infarction: a joint position paper of the Association for Acute CardioVascular Care and the European Society of Cardiology Working Group on Thrombosis

The formation of a thrombus in an epicardial artery may result in an acute myocardial infarction (AMI). Despite major advances in acute treatment using network approaches to allocate patients to timely reperfusion and optimal antithrombotic treatment, patients remain at high risk for thrombotic complications. Ongoing activation of the coagulation system as well as thrombin-mediated platelet activation may both play a crucial role in this context. Whether measurement of circulating biomarkers of coagulation and fibrinolysis could be useful for risk stratification in secondary prevention is currently not fully understood. In addition, measurement of such biomarkers could be helpful to identify thrombus formation as the leading mechanism for AMI. The introduction of biomarkers of myocardial injury such as high-sensitivity cardiac troponins made rule-out of AMI even more precise. However, elevated markers of myocardial injury cannot provide proof of a type 1 AMI, let alone thrombus formation. The combined measurement of markers of myocardial injury with biomarkers reflecting ongoing thrombus formation might be helpful for the fast and correct diagnosis of an atherothrombotic type 1 AMI. This position paper gives an overview of the current knowledge and possible role of biomarkers of coagulation and fibrinolysis for the diagnosis of AMI, risk stratification, and individualized treatment strategies in patients with AMI.

Cardiovascular outcome trials in patients with chronic kidney disease: challenges associated with selection of patients and endpoints

Although cardiovascular disease is a major health burden for patients with chronic kidney disease, most cardiovascular outcome trials have excluded patients with advanced chronic kidney disease. Moreover, the major cardiovascular outcome trials that have been conducted in patients with end-stage renal disease have not demonstrated a treatment benefit. Thus, clinicians have limited evidence to guide the management of cardiovascular disease in patients with chronic kidney disease, particularly those on dialysis. Several factors contribute to both the paucity of trials and the apparent lack of observed treatment effect in completed studies. Challenges associated with conducting trials in this population include patient heterogeneity, complexity of renal pathophysiology and its interaction with cardiovascular disease, and competing risks for death. The Investigator Network Initiative Cardiovascular and Renal Clinical Trialists (INI-CRCT), an international organization of academic cardiovascular and renal clinical trialists, held a meeting of regulators and experts in nephrology, cardiology, and clinical trial methodology. The group identified several research priorities, summarized in this paper, that should be pursued to advance the field towards achieving improved cardiovascular outcomes for these patients. Cardiovascular and renal clinical trialists must partner to address the uncertainties in the field through collaborative research and design clinical trials that reflect the specific needs of the chronic and end-stage kidney disease populations, with the shared goal of generating robust evidence to guide the management of cardiovascular disease in patients with kidney disease.

Randomized Comparison of the Polymer-Free Biolimus-Coated BioFreedom Stent With the Ultrathin Strut Biodegradable Polymer Sirolimus-Eluting Orsiro Stent in an All-Comers Population Treated With Percutaneous Coronary Intervention

Background:

In patients with increased bleeding risk, the biolimus A9-coated BioFreedom stent, a stainless steel drug-coated stent free from polymer, has shown superiority compared with a bare-metal stent. The aim of this study was to investigate whether the BioFreedom stent is noninferior to a modern ultrathin strut biodegradable polymer cobalt-chromium sirolimus-eluting Orsiro stent in an all-comers patient population treated with percutaneous coronary intervention.

Methods:

The SORT OUT IX trial (Scandinavian Organization for Randomized Trials With Clinical Outcome IX), was a large-scale, registry-based, randomized, multicenter, single-blind, 2-arm, noninferiority trial. The primary end point, major adverse cardiovascular events, was defined as the composite of cardiac death, myocardial infarction not related to any segment other than the target lesion, or target lesion revascularization within 1 year, analyzed by intention-to-treat. The trial was powered to assess noninferiority for major adverse cardiovascular events of the BioFreedom stent compared with the Orsiro stent with a predetermined noninferiority margin of 0.021.

Results:

Between December 14, 2015 and April 21, 2017, 3151 patients were assigned to treatment with the BioFreedom stent (1572 patients, 1966 lesions) or to the Orsiro stent (1579 patients, 1985 lesions). Five patients were lost to follow-up because of emigration (99.9% follow-up rate). Mean age was 66.3±10.9, diabetes mellitus was seen in 19.3% of patients, and 53% of the patients had acute coronary syndromes. At 1 year, intention-to-treat analysis showed that 79 (5.0%) patients, who were assigned the BioFreedom stent, and 59 (3.7%), who were assigned the Orsiro stent, met the primary end point (absolute risk difference 1.29% [upper limit of one-sided 95% CI 2.50%]; P noni nferiority =0.14). Significantly more patients in the BioFreedom stent group had target lesion revascularization than those in the Orsiro stent group (55 [3.5%] vs 20 [1.3%], rate ratio 2.77 [95% CI, 1.66–4.62]; P <0.0001).

Conclusions:

The biolimus A9-coated BioFreedom polymer-free stent did not meet criteria for noninferiority for major adverse cardiovascular events at 12 months when compared with the ultrathin strut biodegradable polymer sirolimus-eluting Orsiro stent in an all-comers population

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02623140.

Application of the fourth universal definition of myocardial infarction in clinical practice

Purpose: The Fourth Universal Definition of Myocardial Infarction (MI) has highlighted the different pathophysiological mechanisms that may lead to ischaemic and non-ischaemic myocardial injury and has emphasised that the diagnosis of myocardial infarction requires the presence of acute myocardial ischaemia in the setting of acute myocardial injury. This case based review intends to illustrate basic principles on how to apply this new, revised definition in clinical practice.Methods and Results: The distinction between different types of MIs (type 1 or type 2) and the delineation of MI from acute non-ischaemic myocardial injury may be challenging in individual patients, which is illustrated by presenting and discussing real-life routine cases.Conclusions: Type 1 MI is a consequence of coronary plaque rupture or erosion with intracoronary thrombus formation that is usually apparent on coronary angiography. Plausible triggering mechanisms causing myocardial oxygen supply/demand mismatch must be identified for the diagnosis of type 2 MI and its treatment should focus initially on management of the underlying disease attributable to acute myocardial ischaemia.

Our nearly complete diagnostic trip of thousands of steps begets a new trip therapeutically

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Cardiac Myosin-Binding Protein C to Diagnose Acute Myocardial Infarction in the Pre-Hospital Setting

Background Early triage is essential to improve outcomes in patients with suspected acute myocardial infarction (AMI). This study investigated whether cMyC (cardiac myosin-binding protein), a novel biomarker of myocardial necrosis, can aid early diagnosis of AMI and risk stratification. Methods and Results cMyC and high-sensitivity cardiac troponin T were retrospectively quantified in blood samples obtained by ambulance-based paramedics in a prospective, diagnostic cohort study. Patients with ongoing or prolonged periods of chest discomfort, acute dyspnoea in the absence of known pulmonary disease, or clinical suspicion of AMI were recruited. Discrimination power was evaluated by calculating the area under the receiver operating characteristics curve; diagnostic performance was assessed at predefined thresholds. Diagnostic nomograms were derived and validated using bootstrap resampling in logistic regression models. Seven hundred seventy-six patients with median age 68 [58;78] were recruited. AMI was the final adjudicated diagnosis in 22%. Median symptom to sampling time was 70 minutes. cMyC concentration in patients with AMI was significantly higher than with other diagnoses: 98 [43;855] versus 17 [9;42] ng/L. Discrimination power for AMI was better with cMyC than with high-sensitivity cardiac troponin T (area under the curve, 0.839 versus 0.813; P=0.005). At a previously published rule-out threshold (10 ng/L), cMyC reaches 100% sensitivity and negative predictive value in patients after 2 hours of symptoms. In logistic regression analysis, cMyC is superior to high-sensitivity cardiac troponin T and was used to derive diagnostic and prognostic nomograms to evaluate risk of AMI and death. Conclusions In patients undergoing blood draws very early after symptom onset, cMyC demonstrates improved diagnostic discrimination of AMI and could significantly improve the early triage of patients with suspected AMI.

Should myocardial infarction type 2 be regarded as two separate entities?

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Different Causes of Death in Patients with Myocardial Infarction Type 1, Type 2, and Myocardial Injury

BACKGROUND

Data outlining the mortality and the causes of death in patients with type 1 myocardial infarction, type 2 myocardial infarction, and those with myocardial injury are limited.

METHODS

During a 1-year period from January 2010 to January 2011, all hospitalized patients who had cardiac troponin I measured on clinical indication were prospectively studied. Patients with at least one cardiac troponin I value >30 ng/L underwent case ascertainment and individual evaluation by an experienced adjudication committee. Patients were classified as having type 1 myocardial infarction, type 2 myocardial infarction, or myocardial injury according to the criteria of the universal definition of myocardial infarction. Follow-up was ensured until December 31, 2014. Data on mortality and causes of death were obtained from the Danish Civil Registration System and the Danish Register of Causes of Death.

RESULTS

Overall, 3762 consecutive patients were followed for a mean of 3.2 years (interquartile range 1.3-3.6 years). All-cause mortality differed significantly among categories: Type 1 myocardial infarction 31.7%, type 2 myocardial infarction 62.2%, myocardial injury 58.7%, and 22.2% in patients with nonelevated troponin values (log-rank test; P < .0001). In patients with type 1 myocardial infarction, 61.3% died from cardiovascular causes, vs 42.6% in patients with type 2 myocardial infarction (P = .015) and 41.2% in those with myocardial injury (P < .0001). The overall mortality and the causes of death did not differ substantially between patients with type 2 myocardial infarction and those with myocardial injury.

CONCLUSIONS

Patients with type 2 myocardial infarction and myocardial injury exhibit a significantly higher long-term mortality compared with patients with type 1 myocardial infarction . However, most patients with type 1 myocardial infarction die from cardiovascular causes in contrast to patients with type 2 myocardial infarction and myocardial injury, in whom noncardiovascular causes of death predominate.

How is cardiac troponin released from injured myocardium?

Cardiac troponin I and cardiac troponin T are nowadays the criterion biomarkers for the laboratory diagnosis of acute myocardial infarction due to their very high sensitivities and specificities for myocardial injury. However, still many aspects of their degradation, tissue release and elimination from the human circulation are incompletely understood. Myocardial injury may be caused by a variety of different mechanisms, for example, myocardial ischaemia, inflammatory and immunological processes, trauma, drugs and toxins, and myocardial necrosis is preceded by a substantial reversible prelethal phase. Recent experimental data in a pig model of myocardial ischaemia demonstrated cardiac troponin release into the circulation from apoptotic cardiomyocytes as an alternative explanation for clinical situations with increased cardiac troponin without any other evidence for myocardial necrosis. However, the comparably lower sensitivities of all currently available imaging modalities, including cardiac magnetic resonance imaging for the detection of particularly non-focal myocardial necrosis in patients, has to be considered for cardiac troponin test result interpretation in clinical settings without any other evidence for myocardial necrosis apart from increased cardiac troponin concentrations as well.

Myocardial damage, coagulation activity and the response to thrombin inhibition in unstable coronary artery disease

Unstable coronary artery disease is in most cases associated with plaque rupture, activation of the coagulation system and subsequent intracoronary thrombus formation which may cause myocardial cell damage. The aim of the present analysis was to assess the relation between troponin T, markers of coagulation activity, i.e. prothrombin fragment 1+2, thrombin-antithrombin complex, soluble fibrin and D-dimer, and ischemic events, i.e. death, myocardial (re-)infarction or refractory angina. 320 patients with unstable coronary artery disease were randomized to 72 hours infusion with inogatran, a low molecular weight direct thrombin inhibitor, or unfractionated heparin. Patients with elevated troponin levels had higher levels of prothrombin fragment 1+2, soluble fibrin and D-dimer before, during, and at 24 hours after cessation of anticoagulant treatment. These troponin-positive patients tended to have worse short-term clinical outcome, without relation to markers of coagulation activity. Troponin-negative patients with unchanged or early increased thrombin generation during treatment had a cluster of ischemic events within 24 hours after cessation of the study drug. The 30-day ischemic event rate was 19 % in troponin-negative patients with unchanged or early increased prothrombin fragment 1+2, and 5.7 % in patients with decreased prothrombin fragment 1+2, p=0.006, and similarly 15 % in troponin-negative patients with unchanged or early increased thrombin-antithrombin complex and 4.5 % in patients with decreased thrombin-antithrombin complex, p=0.02. In conclusion, in unstable coronary artery disease a troponin elevation indicates higher risk and higher coagulation activity. However, among the troponin negative patients, with a lower risk and lower coagulation activity, a part of the patients seem to be non-responders to treatment with a thrombin inhibitor expressed as unchanged or raised coagulation activity and a raised risk of ischemic events early after cessation of treatment.

Platelet function testing in acute cardiac care – is there a role for prediction or prevention of stent thrombosis and bleeding?

The role of platelet function testing in acute coronary syndrome patients undergoing percutaneous coronary intervention remains controversial despite the fact that high platelet reactivity is an independent predictor of stent thrombosis and emerging evidence suggests also a link between low platelet reactivity and bleeding. In this expert opinion paper, the Study Group on Biomarkers in Cardiology of the Acute Cardiovascular Care Association and the Working Group on Thrombosis of the European Society of Cardiology aim to provide an overview of current evidence in this area and recommendations for practicing clinicians.

Incidence, Frequency, and Clinical Characteristics of Type 3 Myocardial Infarction in Clinical Practice

OBJECTIVES

Cardiac death in a patient with symptoms and electrocardiographic changes indicative of myocardial ischemia but without available measurements of cardiac biomarkers is designated a type 3 myocardial infarction. We wanted to investigate the incidence, the frequency, and the characteristics of patients diagnosed as type 3 myocardial infarction.

METHODS

The occurrence of deaths in a well-defined geographic region was retrieved from the Danish Civil Registration System during a 1-year period from 2010 to 2011. Complementary data concerning causes of deaths were obtained from the Danish Register of Causes of Death, and ambulance and hospital patient files. Adjudication of the diagnosis was done by 2 local experts and one external senior cardiologist.

RESULTS

A total of 2766 of the 246,723 adult residents in the region had died. A type 3 myocardial infarction was diagnosed in 18 individuals, corresponding to an annual incidence of 7.3/100,000 person-years. During the same 1-year period, 488 patients had other types of myocardial infarction implying a 3.6% frequency of type 3 myocardial infarction (18 of 506) among all myocardial infarctions.

CONCLUSION

Type 3 myocardial infarction is a rare observation in clinical practice with an annual incidence below 10/100,000 person-years and a frequency of 3%-4% among all types of myocardial infarction. If autopsy data are included, the number of type 3 myocardial infarctions will increase.

Use of copeptin for rapid rule-out of acute myocardial infarction

Copeptin is currently understood as a quantitative marker of endogenous stress. It rises rapidly in multiple acute disorders including acute myocardial infarction. As a single variable, it has only modest diagnostic accuracy for acute myocardial infarction. However, the use of copeptin within a dual-marker strategy together with conventional cardiac troponin increases the diagnostic accuracy and particularly the negative predictive value of cardiac troponin alone for acute myocardial infarction. The rapid rule-out of acute myocardial infarction is the only application in acute cardiac care mature enough to merit consideration for routine clinical care. However, the dual-marker approach seems to provide only very small incremental value when used in combination with sensitive or high-sensitivity cardiac troponin assays. This review aims to update and educate regarding the potential and the procedural details, as well as the caveats and challenges of using copeptin in clinical practice.

What to do when you question cardiac troponin values

High-sensitivity cardiac troponin assays enable cardiac troponin measurement with a high degree of analytical sensitivity and a low level of analytical imprecision at the low measuring range. One of the most important advantages of these new assays is that they allow novel, more rapid approaches for ruling in or ruling out acute myocardial infarctions. The increase in the early diagnostic sensitivity of high-sensitivity cardiac troponin assays comes at the cost of a reduced acute myocardial infarction specificity of the biomarker, because more patients with other causes of acute or chronic myocardial injury without overt myocardial ischaemia are detected than with previous cardiac troponin assays. Increased troponin concentrations that do not fit with the clinical presentation are seen in the daily routine, mainly as a result of a variety of pathologies, and if tested in the same sample, even discrepancies between high-sensitivity cardiac troponin I and troponin T test results may sometimes be found as well. In addition, analytically false-positive test results occasionally may occur since no assay is perfect. In this review, we summarise the biochemical, pathophysiological and analytical background of the work-up for such a clinical setting.

Myocardial Infarction Type 2 and Myocardial Injury

BACKGROUND

The development and implementation of sensitive and high-sensitivity cardiac troponin assays has not only expedited the early ruling in and ruling out of acute myocardial infarction, but has also contributed to the identification of patients at risk for myocardial injury with necrosis, as confirmed by the presence of cardiac troponin concentrations above the 99th percentile. Myocardial injury with necrosis may occur either in the presence of overt ischemia from myocardial infarction, or in the absence of overt ischemia from myocardial injury accompanying other conditions. Myocardial infarction type 2 (T2MI) has been a focus of attention; conceptually T2MI occurs in a clinical setting with overt myocardial ischemia where a condition other than an acute atherothrombotic event is the major contributor to a significant imbalance between myocardial oxygen supply and/or demand. Much debate has surrounded T2MI and its interrelationship with myocardial injury.

CONTENT

We provide a detailed overview of the current concepts and challenges regarding the definition, diagnosis, management, and outcomes of T2MI, as well as the interrelationship to myocardial injury, and emphasize several critical clinical concepts for both clinicians and researchers moving forward.

SUMMARY

T2MI and myocardial injury are frequently encountered in clinical practice and are associated with poor outcomes in both the short term and long term. Diagnostic strategies to facilitate the clinical distinction between ischemic myocardial injury with or without an acute atheroma-thrombotic event vs non–ischemic-mediated myocardial injury conditions are urgently needed, as well as evidence-based therapies tailored toward improving outcomes for patients with T2MI.

The Extent of Myocardial Injury During Prolonged Targeted Temperature Management After Out-of-Hospital Cardiac Arrest

AIM

The aim of this study is to evaluate the extent of myocardial injury by cardiac biomarkers during prolonged targeted temperature management of 24 hours vs 48 hours after out-of-hospital cardiac arrest.

METHODS

This randomized Scandinavian multicenter study compares the extent of myocardial injury quantified by area under the curve (AUC) of cardiac biomarkers during prolonged targeted temperature management at 33°C ± 1°C of 24 hours and 48 hours, respectively. Through a period of 2.5 years, 161 comatose out-of-hospital cardiac arrest patients were randomized to targeted temperature management for 24 hours (n = 77) or 48 hours (n = 84). The AUC was calculated using both high-sensitivity cardiac troponin T (hs-cTnT_AUC) and creatine kinase-myocardial band (CK-MB_AUC) that were based upon measurements of these biomarkers every 6 hours upon admission until 96 hours after reaching target temperature.

RESULTS

The median hs-cTnT_AUC of 33,827 ng/L/h (interquartile range [IQR] 11,366-117,690) of targeted temperature management at 24 hours did not differ significantly from that of 28,973 ng/L/h (IQR 10,656-163,655) at 48 hours. In contrast, the median CK-MB_AUC of 1829 μg/L/h (IQR 800-6799) during targeted temperature management at 24 hours was significantly lower than that of 2428 μg/L/h (IQR 1163-10,906) within targeted temperature management at 48 hours, P <.05.

CONCLUSION

This study of comatose out-of-hospital cardiac arrest survivors showed no difference between the extents of myocardial injury estimated by hs-cTnT_AUC of prolonged targeted temperature management of 48 hours vs 24 hours, although the CK-MB_AUC was significantly higher during 48 hours vs 24 hours. Hence, it seems unlikely that the duration of targeted temperature management has a beneficial effect on the extent of myocardial injury after out-of-hospital cardiac arrest, and may even have a worsening effect.

How to use D-dimer in acute cardiovascular care

D-dimer testing is important to aid in the exclusion of venous thromboembolic events (VTEs), including deep venous thrombosis and pulmonary embolism, and it may be used to evaluate suspected aortic dissection. D-dimer is produced upon activation of the coagulation system with the generation and subsequent degradation of cross-linked fibrin by plasmin. Many different assays for D-dimer testing are currently used in routine care. However, these tests are neither standardized nor harmonized. Consequently, only clinically validated assays and assay specific decision limits should be used for routine testing. For the exclusion of pulmonary embolism/deep vein thrombosis, age-adjusted cut-offs are recommend. Clinicians must be aware of the validated use of their hospital's D-dimer assay to avoid inappropriate use of this biomarker in routine care.