Troponin concentrations for stratification of patients with acute coronary syndromes in relation to therapeutic efficacy of tirofiban. PRISM Study Investigators. Platelet Receptor Inhibition in Ischemic Syndrome Management

Type 2 Myocardial Infarction and Long-Term Mortality Risk Factors: A Retrospective Cohort Study

INTRODUCTION

In-hospital risk factors for type 1 myocardial infarction (MI) have been extensively investigated, but risk factors for type 2 MI are still emerging. Moreover, type 2 MI remains an underdiagnosed and under-researched condition. Our aim was to assess survival rates after type 2 MI and to analyze the risk factors for patient prognosis after hospitalization.

METHODS

We conducted a retrospective database analysis of patients with MI diagnosis who were treated in Vilnius University Hospital Santaros Klinikos. A total of 6495 patients with the diagnosis of MI were screened. The primary study endpoint was long-term all-cause mortality. The predictive value of laboratory tests was estimated including blood hemoglobin, D dimer, creatinine, brain natriuretic peptide (BNP), C-reactive protein (CRP), and troponin levels.

RESULTS

Out of all the patients diagnosed with MI there were 129 cases of type 2 MI (1.98%). Death rate almost doubled from 19.4% at 6 months to 36.4% after 2 years of follow-up. Higher age and impaired kidney function were risk factors for death both during hospitalization and after 2 years of follow-up. Lower hemoglobin (116.6 vs. 98.9 g/L), higher creatinine (90 vs. 161.9 μmol/L), higher CRP (31.4 vs. 63.3 mg/l), BNP (707.9 vs. 2999.3 ng/L), and lower left ventricle ejection fraction were all predictors of worse survival after 2 years of follow-up. Preventive medication during hospitalization can decrease the mortality risk: angiotensin-converting enzyme inhibitor (ACEi) (HR 0.485, 95% CI 0.286-0.820) and statins (HR 0.549, 95% CI 0.335-0.900). No significant influence was found for beta blockers (HR 0.662, 95% CI 0.371-1.181) or aspirin (HR 0.901, 95% CI 0.527-1.539).

CONCLUSIONS

There is significant underdiagnosis of type 2 MI (1.98% out of all MIs). If the patient is prescribed a preventive medication like ACEi or statins, the mortality risk is lower. Increased awareness of elevation of laboratory results could help to improve the treatment of these patients and identify the most vulnerable groups.

High-Sensitivity Cardiac Troponin and the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guidelines for the Evaluation and Diagnosis of Acute Chest Pain

The 2021 American Heart Association/American College of Cardiology/American Society of Echocardiography/American College of Chest Physicians/Society for Academic Emergency Medicine/Society of Cardiovascular Computed Tomography/Society for Cardiovascular Magnetic Resonance guidelines for the evaluation and diagnosis of acute chest pain make important recommendations that include the recognition of high-sensitivity cardiac troponin (hs-cTn) as the preferred biomarker, endorsement of 99th percentile upper reference limits to define myocardial injury, and the use of clinical decision pathways, as well as acknowledgment of the uniqueness of women and other patient subsets. Details on how to integrate hs-cTn into clinical practice are less extensively addressed. Clinicians should be aware of some of the analytical aspects related to hs-cTn assays regarding the limit of detection and the limit of quantitation and how they are used clinically, especially for the single sample strategy to rule out acute myocardial infarction. Likewise, it is important for clinicians to understand issues related to the derivation of the 99th percentile upper reference limit; the value of sex-specific 99th percentile upper reference limits; how to use changing concentrations (deltas) to facilitate diagnosis and risk stratification of patients with suspected acute coronary syndrome, including the differentiation of acute from chronic myocardial injury; and how to best integrate the use of hs-cTn with clinical decision pathways. With the use of hs-cTn, conditions such as type 2 myocardial infarction become more common, whereas others such as unstable angina become less frequent but still occur. Sections relating to these issues are included.

Development, validation, and implementation of biomarker testing in cardiovascular medicine state-of-the-art: proceedings of the European Society of Cardiology-Cardiovascular Round Table

Many biomarkers that could be used to assess ejection fraction, heart failure, or myocardial infarction fail to translate into clinical practice because they lack essential performance characteristics or fail to meet regulatory standards for approval. Despite their potential, new technologies have added to the complexities of successful translation into clinical practice. Biomarker discovery and implementation require a standardized approach that includes: identification of a clinical need; identification of a valid surrogate biomarker; stepwise assay refinement, demonstration of superiority over current standard-of-care; development and understanding of a clinical pathway; and demonstration of real-world performance. Successful biomarkers should improve efficacy or safety of treatment, while being practical at a realistic cost. Everyone involved in cardiovascular healthcare, including researchers, clinicians, and industry partners, are important stakeholders in facilitating the development and implementation of biomarkers. This article provides suggestions for a development pathway for new biomarkers, discusses regulatory issues and challenges, and suggestions for accelerating the pathway to improve patient outcomes. Real-life examples of successful biomarkers-high-sensitivity cardiac troponin, T2* cardiovascular magnetic resonance imaging, and echocardiography-are used to illustrate the value of a standardized development pathway in the translation of concepts into routine clinical practice.

Clinical Presentation and Outcome of Patients With Spontaneous Coronary Artery Dissection Versus Atherosclerotic Coronary Plaque Dissection

BACKGROUND

Atherosclerotic coronary plaque dissection (ACPD) is one cause of acute coronary syndrome (ACS) caused by underlying atherosclerosis. Spontaneous coronary artery dissection (SCAD) occurs outside the setting of atherosclerosis among young women and individuals with few or no conventional atherosclerotic risk factors, and has emerged as an important cause of ACS, and sudden death. A comparison between ACPD and SCAD has not been previously addressed in the literature. Our study will compare ACPD and SCAD.

METHODS

Patients with confirmed diagnosis of SCAD and ACPD were retrospectively identified from 30 centers in 4 Arab Gulf countries between January 2011 and December 2017. In-hospital (ventricular tachycardia/ventricular fibrillation, myocardial infarction (MI), percutaneous coronary intervention, dissection extension, cardiogenic shock, death, implantable cardioverter-defibrillator placement) and follow-up (MI, de novo SCAD, spontaneous superior mesenteric artery dissection, death) events were compared between them.

RESULTS

Eighty-three cases of SCAD and 48 ACPD were compared. ACPD patients were more frequently male (91.67% vs. 49.40%, P < 0.001) and older (58.5 vs. 44, P < 0.001). Cardiovascular risk factors were more prevalent in patients with ACPD, including diabetes mellitus (60.4% vs. 25.3%), dyslipidemia (62.5% vs. 38.5%), and hypertension (62.5% vs. 31.3%), P < 0.001. Hospital presentation of ST-elevation MI was diagnosed in 48% of SCAD versus 27% of ACPD patients (P = 0.012). SCAD patients received medical-only treatment in 40% of cases and ACPD in 21% (P = 0.042). In-hospital and follow-up events were comparable in both groups (P = 0.25).

CONCLUSIONS

Despite a completely different pathophysiology of ACS between SCAD and ACPD, in-hospital and follow-up events were comparable.

Safety and efficacy of bivalirudin monotherapy in patients with non-ST-segment elevation acute coronary syndromes with positive biomarkers undergoing percutaneous coronary intervention: a report from the Acute Catheterization and Urgent Intervention Triage Strategy trial

OBJECTIVES

There are limited data on bivalirudin monotherapy in patients with non-ST-segment elevation acute coronary syndromes (NSTE-ACS) with positive biomarkers of myocardial necrosis (troponin and/or creatine kinase-myocardial band isoenzyme). We sought to evaluate the safety and efficacy of bivalirudin monotherapy in patients with positive biomarkers from the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial.

PATIENTS AND METHODS

We compared the net adverse clinical events [composite ischemia - (death, myocardial infarction, or unplanned ischemic revascularization) - or noncoronary artery bypass graft surgery (CABG)-related major bleeding] among patients with biomarker-positive NSTE-ACS in the ACUITY trial overall and by antithrombotic strategy.

RESULTS

Among 13 819 patients with NSTE-ACS enrolled in ACUITY, 4728 patients presented with positive biomarkers and underwent an early invasive strategy. Of those, 1547 were randomized to heparin plus a glycoprotein IIb/IIIa inhibitor (GPI), 1555 to bivalirudin plus GPI, and 1626 to bivalirudin monotherapy. Compared with biomarker-negative patients, biomarker-positive patients had higher 30-day rates of net adverse clinical events (14.0 vs. 12.4%; P = 0.04), all-cause death (1.3 vs. 0.5%; P = 0.001), cardiac death (1.1 vs. 0.5%; P = 0.005), and non-CABG-related major bleeding (6.5 vs. 5.2%, P = 0.03). At 30 days, bivalirudin monotherapy was associated with significantly less non-CABG-related major bleeding (bivalirudin monotherapy 4.1% vs. bivalirudin plus GPI 8.4% vs. heparin plus GPI 7.1%) with comparable rates of composite ischemia (bivalirudin monotherapy 9.2% vs. bivalirudin plus GPI 9.9% vs. heparin plus GPI 8.4%). In a multivariable model, bivalirudin monotherapy was associated with a significant reduction in non-CABG-related major bleeding but was not associated with an increased risk of death, myocardial infarction, unplanned revascularization or stent thrombosis.

CONCLUSION

Compared with heparin plus GPI or bivalirudin plus GPI, bivalirudin monotherapy provides similar protection from ischemic events with less major bleeding at 30 days among patients with NSTE-ACS and positive biomarkers.

Troponin Testing for Clinicians

The analytical performance of troponin assays has improved markedly in the last 2 decades. The variety of assays, their evolution over time, and their critical importance in influencing care, mandates the need for skills in their use. There are 3 critical elements necessary for optimal use of troponin testing in clinical care, as follows: 1) the analytical performance of the assay; 2) the clinical sensitivity and specificity of the test result; and 3) the clinical reasoning for ordering and the proper clinical context for interpreting the test result. This paper provides further explanation that will assist clinicians in their clinical decision making and interpretation of troponin test results. Schematic visual explanations are provided to help clinicians develop a more intuitive understanding of troponin testing.

Relationship Between Peak Troponin Values and Long-Term Ischemic Events Among Medically Managed Patients With Acute Coronary Syndromes

BACKGROUND

The relationship between troponin level and outcomes among patients with non-ST-segment elevation ACS is established, but the relationship of troponin level with long-term outcomes among medically managed non-ST-segment elevation ACS patients receiving contemporary antiplatelet therapy is inadequately defined.

METHODS AND RESULTS

In 6763 medically managed non-ST-segment elevation ACS patients randomized in TRILOGY ACS (Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes) (prasugrel versus clopidogrel), we examined relationships between categories of peak troponin/upper limit of normal (ULN) ratio within 48 hours of the index ACS event (≈4.5 days before randomization) and 30-month outcomes (cardiovascular death, myocardial infarction, or stroke; cardiovascular death or myocardial infarction; and all-cause death). Patients with peak troponin levels <1×ULN were younger, were more often women, and had lower GRACE risk scores than those in other troponin groups. Those with ratios ≥5×ULN were more frequently smokers but less often had prior myocardial infarction or percutaneous coronary intervention. Diabetes mellitus prevalence, body mass index, serum creatinine, and hemoglobin were similar across groups. For all end points, statistically significant differences in 30-month event rates were observed between peak troponin categories. The relationship was linear for 30-month mortality (<1×ULN, n=1849 [6.2%]; 1 to <3×ULN, n=1203 [9.6%]; 3 to <5×ULN, n=581 [10.8%]; and ≥5×ULN, n=3405 [12.8%]) but plateaued for composite end points beyond peak troponin values ≥3×ULN. There was no statistically significant heterogeneity in treatment effect by peak troponin ratio for any end point.

CONCLUSIONS

Among medically managed non-ST-segment elevation ACS patients selected for medical management, there was a graded relationship between increasing peak troponin and long-term ischemic events but no heterogeneity of treatment effect for prasugrel versus clopidogrel according to peak troponin.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00699998.

Cost effectiveness of high-sensitivity troponin compared to conventional troponin among patients presenting with undifferentiated chest pain: A trial based analysis

BACKGROUND

Patients with low and intermediate risk chest pain features comprise the greatest proportion presenting to emergency services for evaluation of suspected acute coronary syndromes (ACS). The efficient and timely identification of patients with these features remains a major challenge within clinical practice. Troponin assays are increasingly being used for the determination of risk among patients presenting with chest pain potentially facilitating more appropriate care. To date, no economic evaluation comparing high-sensitivity troponin T (hs-TnT) reporting to standard troponin T (c-TnT) reporting in the routine management of suspected ACS and based on longer-term clinical outcomes has been conducted.

METHODS AND RESULTS

An economic evaluation was conducted with 1937 participants randomized to either hs-TnT (n=973) or c-TnT (n=964) with 12month follow-up. The primary outcome measure was the number of cumulative combined outcomes of all-cause mortality and new or recurrent ACS avoided. Mean per participant Australian Medicare costs were higher in the hs-TnT arm compared to the c-TnT arm (by $1285/patient). Mean total adverse clinical outcomes avoided were higher in the hs-TnT arm (by 0.0120/patient) resulting in an incremental cost-effectiveness ratio (ICER) of $108,552/adverse clinical outcome avoided. An ICER of $49,030/adverse clinical outcome avoided was obtained when the analysis was restricted to patients below the threshold of normal Troponin testing (actual c-TnT levels <30ng/L).

CONCLUSIONS

hs-TnT reporting leads to fewer adverse clinical events but at a high ICER. For the routine implementation of hs-TnT to be more cost-effective, substantial changes in clinical practice will be required.

CLINICAL TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12614000189628). https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=365726.

Randomized Comparison of High-Sensitivity Troponin Reporting in Undifferentiated Chest Pain Assessment

Background—

High-sensitivity troponin T (hs-TnT) assays promise greater discrimination of evolving myocardial infarction, but the impact of unguided implementation on the effectiveness of care is uncertain.

Methods and Results—

We evaluated the impact of hs-TnT reporting on care and outcome among chest pain patients presenting to 5 emergency departments within a multicenter randomized trial. Patients were allocated to hs-TnT reporting (hs-report) or standard reporting (std-report; Roche Elecys). The primary end point was death and new or recurrent acute coronary syndrome by 12 months. A total of 1937 patients without ST-segment elevation were enrolled between July 2011 and March 2013. The median age was 61 (interquartile range, 48–74) years, and 46.3% were women. During the index hospitalization, 1466 patients (75.7%) had maximal troponin <30 ng/L within 24 hours. Randomization to hs-report format did not alter the admission rate (hs-report: 57.7% versus std-report: 58.0%; P =0.069). There was no difference in angiography (hs-report: 11.9% versus std-report: 10.9%; P =0.479). The hs-reporting did not reduce 12-month death or new/recurrent acute coronary syndrome in the overall population (hs-report: 9.7% versus std-report: 7.2% [hazard ratio, 0.83 (0.57–1.22); P =0.362]). However, among those with troponin levels <30 ng/L, a modest reduction in the primary end point was observed (hs-report: 2.6% versus std-report: 4.4%, [hazard ratio, 0.58; 95% confidence interval, 0.34–0.1.00; P =0.050).

Conclusions—

High-sensitivity troponin reporting alone is associated with only modest changes in practice. Clinical effectiveness in the adoption of high-sensitivity troponin may require close coupling with protocols that guide interpretation and care.

Clinical Trial Registration—

URL: http://www.ANZCTR.org.au . Unique identifier: ACTRN12611000879965.

Routine invasive strategies versus selective invasive strategies for unstable angina and non-ST elevation myocardial infarction in the stent era

BACKGROUND

People with unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI) are managed with a combination of medical therapy, invasive angiography and revascularisation. Specifically, two approaches have evolved: either a 'routine invasive' strategy whereby all patients undergo coronary angiography shortly after admission and, if indicated, coronary revascularisation; or a 'selective invasive' (also referred to as 'conservative') strategy in which medical therapy alone is used initially, with a selection of patients for angiography based upon evidence of persistent myocardial ischaemia. Uncertainty exists as to which strategy provides the best outcomes for these patients. This Cochrane review is an update of a Cochrane review originally published in 2006, to provide a robust comparison of these two strategies in the early management of patients with UA/NSTEMI.

OBJECTIVES

To determine the benefits and harms associated with the following.1. A routine invasive versus a conservative or 'selective invasive' strategy for the management of UA/NSTEMI in the stent era.2. A routine invasive strategy with and without glycoprotein IIb/IIIa receptor antagonists versus a conservative strategy for the management of UA/NSTEMI in the stent era.

SEARCH METHODS

We searched the following databases and additional resources up to 25 August 2015: the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library, MEDLINE and EMBASE, with no language restrictions.

SELECTION CRITERIA

We included prospective randomised controlled trials (RCTs) that compared invasive with conservative or 'selective invasive' strategies in participants with acute UA/NSTEMI.

DATA COLLECTION AND ANALYSIS

Two review authors screened the records and extracted data in duplicate. Using intention-to-treat analysis with random-effects models, we calculated summary estimates of the risk ratio (RR) with 95% confidence intervals (CIs) for the primary endpoints of all-cause death, fatal and non-fatal myocardial infarction (MI), combined all-cause death or non-fatal MI, refractory angina and re-hospitalisation. We performed further analysis of included studies based on whether glycoprotein IIb/IIIa receptor antagonists were used routinely. We assessed the heterogeneity of included trials using Pearson χ² (Chi² test) and variance (I² statistic) analysis. Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, we assessed the quality of the evidence and the GRADE profiler (GRADEPRO) was used to import data from Review Manager 5.3 (Review Manager) to create Summary of findings (SoF) tables.

MAIN RESULTS

Eight RCTs with a total of 8915 participants (4545 invasive strategies, 4370 conservative strategies) were eligible for inclusion. We included three new studies and 1099 additional participants in this review update. In the all-study analysis, evidence did not show appreciable risk reductions in all-cause mortality (RR 0.87, 95% CI 0.64 to 1.18; eight studies, 8915 participants; low quality evidence) and death or non-fatal MI (RR 0.93, 95% CI 0.71 to 1.2; seven studies, 7715 participants; low quality evidence) with invasive strategies compared to conservative (selective invasive) strategies at six to 12 months follow-up. There was appreciable risk reduction in MI (RR 0.79, 95% CI 0.63 to 1.00; eight studies, 8915 participants; moderate quality evidence), refractory angina (RR 0.64, 95% CI 0.52 to 0.79; five studies, 8287 participants; moderate quality evidence) and re-hospitalisation (RR 0.77, 95% CI 0.63 to 0.94; six studies, 6921 participants; moderate quality evidence) with routine invasive strategies compared to conservative (selective invasive) strategies also at six to 12 months follow-up.Evidence also showed increased risks in bleeding (RR 1.73, 95% CI 1.30 to 2.31; six studies, 7584 participants; moderate quality evidence) and procedure-related MI (RR 1.87, 95% CI 1.47 to 2.37; five studies, 6380 participants; moderate quality evidence) with routine invasive strategies compared to conservative (selective invasive) strategies.The low quality evidence were as a result of serious risk of bias and imprecision in the estimate of effect while moderate quality evidence was only due to serious risk of bias.

AUTHORS' CONCLUSIONS

In the all-study analysis, the evidence failed to show appreciable benefit with routine invasive strategies for unstable angina and non-ST elevation MI compared to conservative strategies in all-cause mortality and death or non-fatal MI at six to 12 months. There was evidence of risk reduction in MI, refractory angina and re-hospitalisation with routine invasive strategies compared to conservative (selective invasive) strategies at six to 12 months follow-up. However, routine invasive strategies were associated with a relatively high risk (almost double the risk) of procedure-related MI, and increased risk of bleeding complications. This systematic analysis of published RCTs supports the conclusion that, in patients with UA/NSTEMI, a selectively invasive (conservative) strategy based on clinical risk for recurrent events is the preferred management strategy.

Pharmacological and non pharmacological strategies in the management of coronary artery disease and chronic kidney disease

Patients with advanced chronic kidney disease (CKD), including those treated with dialysis, are at high risk for the development of cardiovascular disease (CVD). CVD accounts for 45-50% of deaths among dialysis patients. Therapy of acute and chronic coronary heart disease (CHD) that is effective in the general population is frequently less effective in patients with advanced CKD. Drug therapy in such patients may require dose modification in some cases. Oral anti-platelet drugs are less effective in those with advanced CKD than in persons with normal or near normal renal function. The intravenous antiplatelet drugs eptifibatide and tirofiban both require dose reductions in patients with advanced CKD. Enoxaparin requires dose reduction in early stage CKD and is contraindicated in hemodialysis patients. Unfractionated heparin and warfarin maybe used without dose adjustment in CKD patients. Atenolol, acetbutolol and nadolol may require dose adjustments in CKD. Metoprolol and carvedilol do not. Calcium channel blockers and nitrates do not require dose adjustment, whereas ranolazine does. Angiotensin converting enzyme inhibitors and angiotensin receptor blockers may safely be used in CKD patients with close observation for hyperkalemia. The safety of spironolactone in such patients is questionable. Statins are less effective in reducing cardiovascular complication in CKD patients and their initiation is not recommended in dialysis patients. Coronary artery bypass grafting is associated with higher short-term mortality, but better long-term morbidity and mortality than percutaneous coronary interventions in patients with advanced CKD with non-ST segment ACS and chronic CHD.

Magnitude of Troponin Elevation and Long-Term Clinical Outcomes in Acute Coronary Syndrome Patients Treated With and Without Revascularization

Background—

In patients with non–ST-segment–elevation acute coronary syndrome (NSTE ACS), elevated troponin levels identify patients at high risk for adverse outcomes; however, it is unknown whether the magnitude of troponin elevation during hospitalization remains predictive of subsequent events in patients undergoing coronary revascularization.

Methods and Results—

We studied 12 635 patients with NSTE ACS in the Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) study with at least 1 troponin measurement during index hospitalization. Cox proportional hazards regression was used to examine the relationship between peak troponin level (standardized as the ratio of peak troponin value measured during hospitalization and local laboratory upper reference limit [URL]) and revascularization on all-cause mortality at 2 years. Revascularization (percutaneous coronary intervention or coronary artery bypass graft) was performed during index hospitalization in 8586 patients (68.0%); revascularized patients had higher peak troponin ratios (median, 23 versus 9.5× URL). Among patients that did not undergo revascularization, the mortality rate at 2 years increased in a curvilinear fashion with increasing levels of peak troponin. In contrast, the mortality rate at 2 years remained constant irrespective of peak troponin levels among revascularized patients ( P for interaction=0.004). This relationship was unchanged after multivariable adjustment.

Conclusions—

There is a differential relationship between the magnitude of troponin elevation and long-term mortality in ACS patients treated with and without revascularization. Although prognostically important in patients treated without revascularization, the prognostic implications of peak troponin level seem to be minimal in revascularized patients.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT00527943.

Troponin elevation in patients without acute coronary syndrome

INTRODUCTION AND OBJECTIVES

Troponins are specific biomarkers of myocardial injury and are implicated in the diagnosis and prognosis of patients with acute coronary syndrome. Our purpose was to determine the clinical characteristics and prognosis of patients with troponin elevation who are not diagnosed with acute coronary syndrome.

METHODS

A total of 1032 patients with an emergency room troponin measurement were studied retrospectively, dividing them into 3 groups: 681 patients with no troponin elevation and without acute coronary syndrome, 139 with acute coronary syndrome, and 212 with troponin elevation and not diagnosed with acute coronary syndrome. The clinical characteristics and in-hospital and 12-month mortality of these 3 groups were compared.

RESULTS

Patients with troponin elevation not diagnosed with acute coronary syndrome were older and had greater comorbidity than patients with acute coronary syndrome or no troponin elevation. The 12-month mortality was 30.2%, compared with 15.1% and 4.7% in the other groups (log rank test, P<.001). In the Cox logistic regression model adjusted for confounding variables, patients with troponin elevation and no diagnosis of acute coronary syndrome had higher mortality compared with patients with negative troponin without acute coronary syndrome (hazard ratio=3.99; 95% confidence interval, 2.36-6.75; P<.001) and similar prognosis as patients with acute coronary syndrome.

CONCLUSIONS

Troponin elevation is an important predictor of mortality, regardless of the patient's final diagnosis.

Decision limits and the reporting of cardiac troponin: Meeting the needs of both the cardiologist and the ED physician

Cardiac troponin is the preferred biomarker for defining the acute coronary syndrome and acute myocardial infarction. Currently, the only decision limit formally endorsed with regard to the cardiac troponins is the 99th percentile. This is a "rule-in" criterion, intended to ensure that only persons with the acute coronary syndrome are reviewed. The 99th percentile is an arbitrary cut point and there are many problems associated with its application, including defining a truly healthy population, the difficulty of standardisation of cardiac troponin assays, especially but not only cardiac troponin I, and the effects of age and sex on this parameter. The Emergency Department (ED) screens many more persons for possible acute coronary syndromes than actually have the condition and their needs are best met by a "rule-out" test that enables them to clear their busy departments of the many persons who do not actually have the condition. The needs of the ED are not optimally met using the 99th percentile. The index of individuality for the cardiac troponins is small and significant changes consistent with an acute coronary syndrome can occur without the 99th percentile being exceeded. It appears that the ED may be better served by use of delta troponin changes rather than the 99th percentile, but there are problems with this approach, particularly in persons who present late when troponin release has plateaued. In addition, there are many non-acute coronary syndrome causes for cardiac troponin release. The needs of the cardiologist and the ED physician are so different that it may be inappropriate for both groups to use the same diagnostic criteria for cardiac troponin, and it is of great importance that cardiac troponin measurement be used as only one part of the assessment of the person presenting with possible acute coronary syndrome.

Tirofiban in acute coronary syndromes

Acute coronary syndromes represent a major health problem in terms of incidence and mortality. Intracoronary platelet-rich thrombi may develop in response to plaque rupture, and are involved in the pathogenesis of all acute coronary syndromes. The glycoprotein IIb/IIIa receptor, a platelet surface integrin, plays a key role in platelet aggregation once it has been activated by specific ligands. The development of glycoprotein IIb/IIIa inhibitors has revolutionized the management of acute coronary syndromes. Tirofiban is one of three parenteral glycoprotein IIb/IIIa inhibitors in clinical use, and many trials have demonstrated its clinical efficacy and low rate of adverse effects in patients with non-ST-segment elevation acute coronary syndrome. This article reviews the data concerning its use in the clinical settings of acute coronary syndromes and percutaneous coronary angioplasty, and discusses its benefits in different treatment strategies and in association with other drugs. In particular, the role of early, upstream tirofiban coupled with early aggressive revascularization in the management of high-risk non-ST-segment elevation acute coronary syndromes is emphasized.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. Glycoprotein IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction. This is an update of a Cochrane review first published in 2001, and previously updated in 2007 and 2010.

OBJECTIVES

To assess the efficacy and safety effects of glycoprotein IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 12, 2012), MEDLINE (OVID, 1946 to January Week 1 2013) and EMBASE (OVID, 1947 to Week 1 2013) on 11 January 2013.

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. We used odds ratios (OR) and 95% confidence intervals (CI) for effect measures.

MAIN RESULTS

Sixty trials involving 66,689 patients were included. During PCI (48 trials with 33,513 participants) glycoprotein IIb/IIIa blockers decreased all-cause mortality at 30 days (OR 0.79, 95% CI 0.64 to 0.97) but not at six months (OR 0.90, 95% CI 0.77 to 1.05). All-cause death or myocardial infarction was decreased both at 30 days (OR 0.66, 95% CI 0.60 to 0.72) and at six months (OR 0.75, 95% CI 0.64 to 0.86), although severe bleeding was increased (OR 1.39, 95% CI 1.21 to 1.61; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without acute coronary syndromes.As initial medical treatment of NSTEACS (12 trials with 33,176 participants), IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.90, 95% CI 0.79 to 1.02) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or myocardial infarction at 30 days (OR 0.91, 95% CI 0.85 to 0.98) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.29, 95% CI 1.14 to 1.45; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous glycoprotein IIb/IIIa blockers reduce the risk of all-cause death at 30 days but not at six months, and reduce the risk of death or myocardial infarction at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with acute coronary syndromes. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or myocardial infarction.

Platelet glycoprotein IIb/IIIa blockers during percutaneous coronary intervention and as the initial medical treatment of non-ST segment elevation acute coronary syndromes

BACKGROUND

During percutaneous coronary intervention (PCI), and in non-ST segment elevation acute coronary syndromes (NSTEACS), the risk of acute vessel occlusion by thrombosis is high. Glycoprotein IIb/IIIa blockers strongly inhibit platelet aggregation and may prevent mortality and myocardial infarction. This is an update of a Cochrane review first published in 2001, and previously updated in 2007 and 2010.

OBJECTIVES

To assess the efficacy and safety effects of glycoprotein IIb/IIIa blockers when administered during PCI, and as initial medical treatment in patients with NSTEACS.

SEARCH METHODS

We updated the searches of the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 12, 2012), MEDLINE (OVID, 1946 to January Week 1 2013) and EMBASE (OVID, 1947 to Week 1 2013) on 11 January 2013.

SELECTION CRITERIA

Randomised controlled trials comparing intravenous IIb/IIIa blockers with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion, assessed trial quality and extracted data. We collected major bleeding as adverse effect information from the trials. We used odds ratios (OR) and 95% confidence intervals (CI) for effect measures.

MAIN RESULTS

Sixty trials involving 66,689 patients were included. During PCI (48 trials with 33,513 participants) glycoprotein IIb/IIIa blockers decreased all-cause mortality at 30 days (OR 0.79, 95% CI 0.64 to 0.97) but not at six months (OR 0.90, 95% CI 0.77 to 1.05). All-cause death or myocardial infarction was decreased both at 30 days (OR 0.66, 95% CI 0.60 to 0.72) and at six months (OR 0.75, 95% CI 0.64 to 0.86), although severe bleeding was increased (OR 1.39, 95% CI 1.21 to 1.61; absolute risk increase (ARI) 8.0 per 1000). The efficacy results were homogeneous for every endpoint according to the clinical condition of the patients, but were less marked for patients pre-treated with clopidogrel, especially in patients without acute coronary syndromes.As initial medical treatment of NSTEACS (12 trials with 33,176 participants), IIb/IIIa blockers did not decrease mortality at 30 days (OR 0.90, 95% CI 0.79 to 1.02) or at six months (OR 1.00, 95% CI 0.87 to 1.15), but slightly decreased death or myocardial infarction at 30 days (OR 0.91, 95% CI 0.85 to 0.98) and at six months (OR 0.88, 95% CI 0.81 to 0.96), although severe bleeding was increased (OR 1.29, 95% CI 1.14 to 1.45; ARI 1.4 per 1000).

AUTHORS' CONCLUSIONS

When administered during PCI, intravenous glycoprotein IIb/IIIa blockers reduce the risk of all-cause death at 30 days but not at six months, and reduce the risk of death or myocardial infarction at 30 days and at six months, at a price of an increase in the risk of severe bleeding. The efficacy effects are homogeneous but are less marked in patients pre-treated with clopidogrel where they seem to be effective only in patients with acute coronary syndromes. When administered as initial medical treatment in patients with NSTEACS, these agents do not reduce mortality although they slightly reduce the risk of death or myocardial infarction.

Management of coronary atherosclerosis and acute coronary syndromes in patients with chronic kidney disease

Atherosclerosis of the coronary arteries is common, extensive, and more unstable among patients with chronic renal impairment or chronic kidney disease (CKD). The initial presentation of coronary disease is often acute coronary syndrome (ACS) that tends to be more complicated and has a higher risk of death in this population. Medical treatment of ACS includes antianginal agents, antiplatelet therapy, anticoagulants, and pharmacotherapies that modify the natural history of ventricular remodeling after injury. Revascularization, primarily with percutaneous coronary intervention and stenting, is critical for optimal outcomes in those at moderate and high risk for reinfarction, the development of heart failure, and death in predialysis patients with CKD. The benefit of revascularization in ACS may not extend to those with end-stage renal disease because of competing sources of all-cause mortality. In stable patients with CKD and multivessel coronary artery disease, observational studies have found that bypass surgery is associated with a reduced mortality as compared with percutaneous coronary intervention when patients are followed for several years. This article will review the guidelines-recommended therapeutic armamentarium for the treatment of stable coronary atherosclerosis and ACS and give specific guidance on benefits, hazards, dose adjustments, and caveats concerning patients with baseline CKD.

Use of high-sensitivity troponin assays predicts mortality in patients with normal conventional troponin assays on admission-insights from a meta-analysis

BACKGROUND

Use of high-sensitivity troponin (hs-Tn) assays can detect small levels of myocardial damage previously undetectable with conventional troponin (c-Tn) assays. However, prognostic utility of these hs-Tn assays in prediction of mortality remains unclear in the presence of nonelevated c-Tn levels on admission. A systematic review and meta-analysis was performed to assess mortality risk of patients with hs-Tn elevations in the setting of normal c-Tn levels.

HYPOTHESIS

Patients with hs-Tn elevations with normal c-Tn levels on admission blood samples, drawn to rule out acute coronary syndrome (ACS), have a higher mortality risk than those without hs-Tn or c-Tn elevations.

METHODS

A search was made of the PubMed, CENTRAL, EMBASE, CINAHL, EBSCO, and Web of Science databases. Studies evaluating patients with suspected ACS that reported mortality rates for those with elevated hs-Tn levels but normal c-Tn levels on admission were included. A random-effects model was used to pool event rates, and data were reported in odds ratios (95% confidence interval).

RESULTS

Four studies (N = 2033, mean age 64-75 years, 49%-70% male) revealed that nearly 32% of suspected ACS patients with normal c-Tn levels on admission had elevated hs-Tn levels. Elevated hs-Tn levels conferred a significantly higher risk of all-cause mortality vs normal hs-Tn levels (odds ratio: 4.35, 95% confidence interval: 2.81-6.73, P < 0.01), with negligible heterogeneity (I(2) = 0%).

CONCLUSIONS

Elevation of hs-Tn levels predicted a higher risk of mortality in patients with suspected ACS and may aid in the early identification of higher-risk patients in this setting. Future studies are needed to investigate further optimal management strategies.

Update on platelet glycoprotein IIb/IIIa inhibitors: recommendations for clinical practice

Antiplatelet therapy is the cornerstone of treatment for patients with acute coronary syndrome (ACS) and undergoing percutaneous coronary intervention (PCI). Glycoprotein IIb/IIIa receptors mediate platelet aggregation, representing the final common pathway of platelet-mediated thrombosis. Therefore, agents blocking this pathway may be desirable for the treatment of patients with ACS and PCI. Glycoprotein IIb/IIIa receptor inhibitors have been widely investigated and have been key to the pharmacological advancements in the field. However, although GPIs have been important to reduce ischemic complications, their elevated risk of bleeding complications remains a major limitation. The poor prognostic implications, including increased mortality, associated with bleeding complication underscores the need for alternative treatment options. Over the past years there have been several advancements in antithrombotic pharmacology which have led to changes in recommendations for GPI usage in clinical practice. This is an overview of the most recent clinical trial data on GPIs, and provides practical insight on their modern day use in ACS therapy.

Intracoronary abciximab in STEMI using local drug delivery catheter - single center experience

BACKGROUND

Despite restoration of epicardial flow during primary PCI in STEMI, microvascular obstruction may persist as a result of both atheromatous and thrombotic embolization and vasospasm. Compared with the systemic administration of IV pharmaco-therapies, highly localized administration of intracoronary pharmacotherapy may be associated with a several-hundred-fold increase in the local concentration of an agent in the epicardial artery and microcirculation. Despite restoration of epicardial flow during primary PCI in STEMI, microvascular obstruction may persist as a result of both atheromatous and thrombotic embolization and vasospasm. We are presenting our experience with use of intracoronary abciximab using local drug delivery catheter in STEMI patients.

METHODS

We retrospectively evaluated 15 patients presented to us with STEMI undergoing primary PCI between March 2011 and September 2012 who had super selective intracoronary abciximab using local drug delivery catheter. With standard antiplatelet therapy, both Pre and Post TIMI flow, TMP grading were assessed.

RESULTS

Mean age was 55 years. The TIMI flow increased by 3 grades in thirteen patients, TMP grading increased by 2 grades in five patients and by 3 grades in nine patients. Thus TIMI flow and TMP grading improved after super selective intracoronary abciximab.

CONCLUSION

Super selective intracoronary abciximab using local drug delivery catheter during primary PCI in STEMI patients significantly improves TMP grading without increased risk of bleeding. This benefit is achieved even in patients without thrombus aspiration. We need to assess the long-term outcomes in the form of reduction in infarct size using this strategy in large group of patients.

Circulating miRNAs: novel biomarkers of acute coronary syndrome?

Acute coronary syndrome refers to any group of clinical symptoms compatible with acute myocardial infarction (AMI). AMI is a major cause of death and disability worldwide with the greatest risk of death within the first hours of AMI onset. Therefore, delays in ‘ruling in’ AMI may increase morbidity and mortality due to the time lag in initiating therapy. Likewise, since the majority of patients presenting with acute chest pain do not have AMI, the rapid ‘ruling out’ of AMI in those patients would increase emergency department triage efficiency, decrease medical costs, and reduce morbidity and mortality. Thus, the identification of novel biomarkers that improve current strategies and/or accurately identify subjects who are at risk of developing acute and chronic manifestations of cardiovascular disease are desperately needed. This article discusses the potential of peripheral blood microRNAs as clinical biomarkers for the diagnosis and prognosis of cardiovascular diseases such as AMI.

A review of troponins in ischemic heart disease and other conditions

Measuring cardiac troponin (cTn) I and T levels is currently considered to be a cornerstone for making the diagnosis of acute coronary syndrome (ACS).Based on current literature, cTnI and cTnT are known to be very sensitive and specific for myocardial damage, regardless of the underlying cause. Lately, it has been found that cTns can be elevated and reflect worse prognoses in many situations where ACS is excluded. Such information can affect the validity of cTns as markers for ACS without classic symptoms. This may call for a revision of the troponin cutoff values to make a diagnosis of ACS. Furthermore, it opens a new field of study to determine appropriate management of patients with elevated cTn levels in whom ACS has been excluded.

The platelet fibrinogen receptor: from megakaryocyte to the mortuary

Platelets are integral to normal haemostatic function and act to control vascular haemorrhage with the formation of a stable clot. The fibrinogen receptor (glycoprotein IIb/IIIa [GPIIb/IIIa]) is the most abundant platelet integrin and, by binding fibrinogen, facilitates irreversible binding of platelets to the exposed extracellular matrix and enables the cross-linking of adjacent platelets. The vital role of GPIIb/IIIa requires tight control of both its synthesis and function. After transcription from distinct domains on chromosome 17, the two subunits of the heterodimer are carefully directed through organelles with intricate regulatory steps designed to prevent the cellular expression of a dysfunctional receptor. Similarly, exquisite control of platelet activation via bidirectional signalling acts to limit the inappropriate and excessive formation of platelet-mediated thrombus. However, the enormous diversity of genetic mutations in the fibrinogen receptor has resulted in a number of allelic variants becoming established. The Pro³³ polymorphism in GPIIIa is associated with increased cardiovascular risk due to a pathological persistence of outside-in signalling once fibrinogen has dissociated from the receptor. The polymorphism has also been associated with the phenomenon of aspirin resistance, although larger epidemiological studies are required to establish this conclusively. A failure of appropriate receptor function due to a diverse range of mutations in both structural and signalling domains, results in the bleeding diathesis Glanzmann's thrombasthaenia. GPIIb/IIIa inhibitors were the first rationally designed anti-platelet drugs and have proven to be a successful therapeutic option in high-risk primary coronary intervention. As our understanding of bidirectional signalling improves, more subtle and directed therapeutic strategies may be developed.

Biomarkers in cardiovascular clinical trials: past, present, future

BACKGROUND

Cardiovascular (CV) clinical trials are instrumental in understanding treatment effects and offer insights into the natural progression of CV disease. Biomarkers are a critical component of patient selection, end point definition, and safety monitoring, and clinical trials provide a platform for the discovery and validation of new biomarkers that may augment the understanding of disease mechanisms, risk stratification, and/or clinical decision-making.

CONTENT

We review the roles that biomarkers have played in CV clinical trials and roles that CV clinical trials have played and will continue to play in the discovery and validation of biomarkers and their implementation in clinical practice. Large biobanks containing multiple specimen types are increasingly being created from patients enrolled in clinical trials, and such biobanks, when coupled with advances in molecular techniques and bioinformatics, promise to accelerate our understanding of CV disease mechanisms and to help fuel the discovery and development of novel therapeutic targets and biomarkers of risk and treatment response.

SUMMARY

The past, present, and future of biomarkers and clinical trials have been and will remain intertwined. Biomarkers were once the workhorses of patient selection and end point definition in clinical trials; more recently, clinical trials have been the proving ground for individual biomarkers. Attention to biobanking and the application of modern informatics and molecular techniques to samples collected within clinical trials will usher in the era of stratified and personalized medicine.

Improved diagnostic and prognostic performance of a new high-sensitive troponin T assay in patients with acute coronary syndrome

BACKGROUND

In the present study, we aimed to analyze the diagnostic and prognostic potential of a newly developed high-sensitive troponin T assay and compared these results with those of a contemporary troponin T assay in 2 distinct patient cohorts, one including patients with evident ACS and the other one including patients with general chest pain.

METHODS AND RESULTS

For this study, we analyzed data from 2 independent patient cohorts, the Bad Nauheim ACS registry and the Prognosis in Acute Coronary Syndromes registry, with a total of 2,506 patients. On admission, clinical data have been recorded, and a single measurement of troponin T has been performed with a contemporary assay (TnT) and a new high-sensitive troponin T assay (hsTnT). Clinical follow-up has been obtained after 6 months. The diagnostic value of hsTnT was superior to TnT (area under the receiver operating characteristic curve 0.949 vs 0.929, P = .016). Specifically, in TnT-negative patients, hsTnT provided strong diagnostic information (area under the receiver operating characteristic curve of 0.81, P < .001). Furthermore, hsTnT provided independent prognostic power for mortality within 6 months in both cohorts, which was superior to that of the contemporary TnT assay.

CONCLUSION

Troponin T measured with a newly developed hsTnT provides better diagnostic and prognostic information and, therefore, should be implemented as a standard test in clinical routine.

Integrated SPECT/CT for assessment of haemodynamically significant coronary artery lesions in patients with acute coronary syndrome

PURPOSE

Early risk stratification in patients with non-ST elevation acute coronary syndromes (NSTE-ACS) is important since the benefit from more aggressive and costly treatment strategies is proportional to the risk of adverse clinical events. In the present study we assessed whether hybrid single photon emission computed tomography (SPECT)/coronary computed tomography angiography (CCTA) technology could be an appropriate tool in stratifying patients with NSTE-ACS.

METHODS

SPECT/CCTA was performed in 90 consecutive patients with NSTE-ACS. The Thrombolysis in Myocardial Infarction risk score (TIMI-RS) was used to classify patients as low- or high-risk. Imaging was performed using SPECT/CCTA to identify haemodynamically significant lesions defined as >50% stenosis on CCTA with a reversible perfusion defect on SPECT in the corresponding territory.

RESULTS

CCTA demonstrated at least one lesion with >50% stenosis in 35 of 40 high-risk patients (87%) as compared to 14 of 50 low-risk patients (35%; TIMI-RS<3; p<.0001). Of the 40 high-risk and 50 (16%) low-risk TIMI-RS patients, 16 (40%) and 8 (16%), respectively, had haemodynamically significant lesions (p=0.01). Patients defined as high-risk by a high TIMI-RS, a positive CCTA scan or both (n=45) resulted in a sensitivity of 95%, specificity of 49%, PPV of 35% and NPV of 97% for having haemodynamically significant coronary lesions. Those with normal perfusion were spared revascularization procedures, regardless of their TIMI-RS.

CONCLUSION

Noninvasive assessment of coronary artery disease by SPECT/CCTA may play an important role in risk stratification of patients with NSTE-ACS by better identifying the subgroup requiring intervention.

Anticoagulation in the management of non-ST-segment elevation acute coronary syndrome

There are currently over 1 million patients admitted to hospitals in the United States with the diagnosis of non-ST-segment elevation acute coronary syndrome (NSTE ACS). Due to the significant morbidity and mortality associated with NSTE ACS, appropriate use of the numerous medications employed is critical in ensuring optimal outcomes. Because atherosclerotic plaque rupture and thrombus formation are the central pathophysiologic process in patients with NSTE ACS, it is important to utilize effective and safe combinations of antiplatelet and anticoagulant drug therapy. There are a number of different anticoagulant agents available for use in patients with NSTE ACS, but it is essential to have an in-depth knowledge of the setting in which these agents have been investigated, what current consensus guidelines recommend, as well as an appreciation for the treatment approach and philosophy of the institution for management of patients with NSTE ACS. In this review manuscript, the reader will find an evaluation of the current guidelines concerning the use of anticoagulant therapy in patients with NSTE ACS, as well as a detailed examination of the literature with critical analysis on issues that should be considered when deciding on the appropriate implementation of anticoagulant therapy in protocols for NSTE ACS patients.

[Acute coronary syndrome. A diffuse diagnosis]

Acute coronary syndrome is one of the most common reasons for a presentation in an emergency room. The biggest component of the overall mortality in adults is acute coronary syndrome or in this context its complications. The term "acute coronary syndrome" comprises on one hand 3 entities--unstable angina pectoris, Non-ST-elevation myocardial infarction and ST-elevation myocardial infarction. On the other hand particularly in emergency medicine the term is used as a working diagnosis for patients with unclear, acute chest pain. Although the underlying disease has not changed, especially with the introduction of troponins and the changes of their reference values the concept and importance of acute myocardial infarction has changed. This article emphasises on the current nomenclature and its importance for the adequate diagnosis and treatment are explained.