Third universal definition of myocardial infarction

The diagnostic challenge of myocardial infarction in critically ill patients: do high-sensitivity troponin measurements add more clarity or more confusion?

In ICU settings, the diagnosis and treatment of acute myocardial infarction (AMI) are challenging, partly because cardiac troponin increase occurs frequently. In the previous issue of Critical Care, Ostermann and colleagues reported that myocardial infarction (MI), screened by plasma troponin and electrocardiography changes, is common and often clinically unrecognized in the ICU. Although the clinical significance of underdiagnosed MIs remains unclear, this approach may help to target and further investigate the at-risk population for appropriate therapy.

Use of Observed Within-Person Variation of Cardiac Troponin in Emergency Department Patients for Determination of Biological Variation and Percentage and Absolute Reference Change Values

BACKGROUND

Many patients presenting to the emergency department (ED) for assessment of possible acute coronary syndrome (ACS) have low cardiac troponin concentrations that change very little on repeat blood draw. It is unclear if a lack of change in cardiac troponin concentration can be used to identify acutely presenting patients at low risk of ACS.

METHODS

We used the hs-cTnI assay from Abbott Diagnostics, which can detect cTnI in the blood of nearly all people. We identified a population of ED patients being assessed for ACS with repeat cTnI measurement who ultimately were proven to have no acute cardiac disease at the time of presentation. We used data from the repeat sampling to calculate total within-person CV (CVT) and, knowing the assay analytical CV (CVA), we could calculate within-person biological variation (CVi), reference change values (RCVs), and absolute RCV delta cTnI concentrations.

RESULTS

We had data sets on 283 patients. Men and women had similar CVi values of approximately 14%, which was similar at all concentrations <40 ng/L. The biological variation was not dependent on the time interval between sample collections (t = 1.5–17 h). The absolute delta critical reference change value was similar no matter what the initial cTnI concentration was. More than 90% of subjects had a critical reference change value <5 ng/L, and 97% had values of <10 ng/L.

CONCLUSIONS

With this hs-cTnI assay, delta cTnI seems to be a useful tool for rapidly identifying ED patients at low risk for possible ACS.

Diagnosis and outcome in a prehospital cohort of patients with bundle branch block and suspected acute myocardial infarction

BACKGROUND

Immediate revascularization is beneficial in patients with presumed new-onset bundle branch block myocardial infarction (BBBMI). In the prehospital setting, it is a challenge to diagnose new-onset BBBMI and triage accordingly.

METHODS

ECG, final diagnosis, and mortality were assessed in a prehospital cohort of 4905 consecutive patients with suspected acute myocardial infarction (AMI). Bundle branch block (BBB) was defined as QRS duration ≥120 ms caused by delayed intraventricular conduction. Mortality and angiography data were obtained from the Central Office of Civil Registration and the Western Denmark Heart Registry. Definite diagnosis of AMI and the onset of BBB were determined by expert consensus. Patients were divided into four groups: with or without AMI and with or without BBB. Mortality was evaluated by Kaplan-Meier plots and compared using log-rank statistics.

RESULTS

AMI was diagnosed in 954 patients, of whom 118 had BBB. In 3951 patients without AMI, 436 had BBB. Patients with BBBMI were less often revascularized than patients with AMI without BBB (24 vs. 54%, p<0.001). BBBMI was categorized as new onset in 43 patients of whom two were triaged for acute angioplasty. One-year mortality was 47.2, 17.5, 20.8, and 8.6% (log-rank <0.001) in patients with BBBMI, patients with AMI without BBB, patients with BBB without AMI, and patients without AMI or BBB, respectively.

CONCLUSIONS

Patients with BBBMI have a high mortality. Less than 25% undergo revascularization and only very few patients with new-onset BBBMI are transferred for urgent revascularization. Focus on improving triage and prehospital identification of high-risk patients with BBB and chest pain could improve outcome.

Mean platelet volume on admission improves risk prediction in patients with acute coronary syndromes

Our aim was to evaluate the incremental predictive value of adding mean platelet volume (MPV) to the Global Registry of Acute Coronary Events (GRACE) risk score. The MPV and GRACE score were determined on admission in 509 consecutive patients with acute coronary syndrome (ACS). Six-month mortality or nonfatal myocardial infarction (MI) was the study end point. Overall, 61 (12%) patients reached the combined end point. Cox multivariate analysis showed that an elevated MPV was an independent predictor of 6-month mortality or MI in patients with ACS. The addition of MPV to the GRACE model improved its global fit and discriminatory capacity. The new model including MPV allowed adequate reclassification of 16% of the patients. In conclusion, the inclusion of MPV into the GRACE risk score could allow improved risk classification, thereby refining risk stratification of patients with ACS.

Prognosis of patients with non-ST-segment-elevation myocardial infarction and nonobstructive coronary artery disease: propensity-matched analysis from the Acute Catheterization and Urgent Intervention Triage Strategy trial

BACKGROUND

Troponin elevation is a risk factor for mortality in patients with non-ST-segment-elevation acute coronary syndromes. However, the prognosis of patients with troponin elevation and nonobstructive coronary artery disease (CAD) is unknown. Our objective was therefore to evaluate the impact of nonobstructive CAD in patients with non-ST-segment-elevation acute coronary syndromes and troponin elevation enrolled in the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial.

METHODS AND RESULTS

In the ACUITY trial, 3-vessel quantitative coronary angiography was performed in a formal substudy of 6921 patients presenting with non-ST-segment-elevation acute coronary syndromes. Patients with elevated admission troponin levels were stratified by the presence or absence of obstructive CAD (any lesion with quantitative diameter stenosis >50%). Propensity score matching was performed to adjust for baseline characteristics. Of 2442 patients with elevated troponin, 197 (8.8%) had nonobstructive CAD. Maximum diameter stenosis was 87.4 (73.2, 100.0) versus 22.6 (19.2, 25.7; P<0.0001) in patients with versus without obstructive CAD, respectively. Propensity matching yielded 117 patients with nonobstructive CAD and 331 patients with obstructive CAD, with no significant baseline differences between groups. In the matched cohort, overall 1-year mortality was significantly higher in patients with nonobstructive CAD (5.2% versus 1.6%; hazard ratio [95% confidence interval]=3.44 [1.05, 11.28]; P=0.04), driven by greater noncardiac mortality. Conversely, recurrent myocardial infarction and unplanned revascularization rates were significantly higher in patients with obstructive CAD.

CONCLUSIONS

Patients with non-ST-segment-elevation acute coronary syndromes and elevated troponin levels but without obstructive CAD, while having low rates of subsequent myocardial infarction and unplanned revascularization, are still at considerable risk for 1-year mortality from noncardiac causes.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00093158.

Predictive value of circulating miR-328 and miR-134 for acute myocardial infarction

MicroRNA (miRNAs) is demonstrated to be present in the blood of humans and has been increasingly suggested as a novel biomarker for various pathological processes in the heart, including myocardial infarction, myocardial remodeling and progression to heart failure. In this study, we aim to evaluate the diagnostic and prognostic value of circulating miR-328 and miR-134 in patients with acute myocardial infarction (AMI). Circulating levels of miR-328 and miR-134 were detected by quantitative real-time PCR in plasma samples from 359 AMI patients and 30 healthy volunteers. Concentrations of high-sensitivity cardiac troponin T (hs-cTnT) were measured using electrochemiluminescence-based methods. MiRNAs were assessed for discrimination of a clinical diagnosis of AMI and for association with primary clinical endpoint defined as a composite of cardiogenic death and development of heart failure within 6 months after infarction. Results showed that levels of plasma miR-328 and miR-134 were significantly higher in AMI patients than in healthy controls. Receiver operating characteristic curve analyses showed significant diagnostic value of miR-328 and miR-134 for AMI. However, neither of them was superior to hs-cTnT for the diagnosis. Additionally, increased miRNA levels were strongly associated with increased risk of mortality or heart failure within 6 months for miR-328 (OR 7.35, 95 % confidence interval 1.07-17.83, P < 0.001) and miR-134 (OR 2.28, 95 % confidence interval 1.03-11.32 P < 0.001). In conclusion, circulating miR-328 and miR-134 could be potential indicators for AMI, and the miRNA levels are associated with increased risk of mortality or development of heart failure.

Decade-long trends in the magnitude, treatment, and outcomes of patients aged 30 to 54 years hospitalized with ST-segment elevation and non-ST-segment elevation myocardial infarction

Although acute myocardial infarction (AMI) occurs primarily in the elderly, this disease also affects young adults. Few studies have, however, presented data on relatively young patients hospitalized with AMI. The objectives of this population-based study were to examine recent trends in the magnitude, clinical characteristics, management, and in-hospital and long-term outcomes associated with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) in patients aged 30 to 54 years. We reviewed the medical records of 955 residents of the Worcester (Massachusetts) metropolitan area aged 30 to 54 years who were hospitalized for an initial STEMI or NSTEMI in 6 biennial periods from 1999 to 2009 at 11 greater Worcester medical centers. From 1999 to 2009, the proportion of young adults hospitalized with an STEMI decreased from approximately 2/3 to 2/5 of all patients with an initial AMI. Patients with STEMI were less likely to have a history of heart failure, hypertension, hyperlipidemia, and kidney disease than those with NSTEMI. Both groups received similar effective medical therapies during their acute hospitalization. In-hospital clinical complications and mortality were low and no significant differences in these end points were observed between patients with STEMI and NSTEMI or with regard to 1-year postdischarge death rates (1.9% vs 2.8%). The present results demonstrate recent decreases in the proportion of relatively young patients diagnosed with an initial STEMI. Patients with STEMI and NSTEMI had similar in-hospital outcomes and long-term survival. Trends in these and other important outcomes warrant continued monitoring.

Prognostic utility of serum vitronectin levels in acute myocardial infarction

BACKGROUND

Vitronectin (VN) functions as a regulator of platelet adhesion and aggregation, coagulation, and fibrinolysis. The aim of this study was to assess the prognostic significance of serum VN levels in patients with acute myocardial infarction (MI).

METHODS

In this study 62 patients admitted with ST-elevation myocardial infarction (STEMI), or non-ST-elevation myocardial infarction (NSTEMI) were enrolled. Serum VN levels were measured within 6 h after onset of chest pains.

RESULTS

The VN serum levels were higher in MI patients with a mean of 2.257 µg/ml (range 1.541-4.493 µg/ml) in the STEMI group, 1.785 µg/ml (range 1.372-4.113 µg/ml) in the NSTEMI group, and 1.222 µg/ml (range 1.033-1.466 µg/ml) in the controls (p = 0.012). Major adverse cardiovascular events could be predicted at 6 months using VN levels independently of other variables [odds ratio (OR) 9.87, 95 % confidence interval (CI) 2.54-47.37, p = 0.001]. There was a significant positive correlation between VN levels and the Gensini score in NSTEMI patients (r = 0.436, p = 0.013).

CONCLUSION

The VN level may be relevant as a clinical biomarker for adverse cardiovascular outcomes not only in patients with ischemic heart disease undergoing coronary interventions, as previously reported, but also in coronary artery disease patients presenting with acute MI.

Determinants of high sensitivity cardiac troponin T elevation in acute ischemic stroke

BACKGROUND

A proportion of patients with acute ischemic stroke have elevated cardiac troponin levels and ECG changes suggestive of cardiac injury, but the etiology is unclear. The aims of this study were to assess the frequency of high sensitivity cardiac troponin T (hs-cTnT) elevation, to identify determinants and ECG changes associated with hs-cTnT elevation, to identify patients with myocardial ischemia and to assess the impact of hs-cTnT elevation on in-hospital mortality.

METHODS

Patients discharged with a diagnosis of acute ischemic stroke during a 1-year period, were included. Patients diagnosed with acute myocardial infarction (MI) within the last 7 days before admission or during hospitalization were excluded.

RESULTS

In all, 156 (54.4%) of 287 patients had elevated hs-cTnT. The factors independently associated with hs-cTnT elevation were age ≥ 76 years (OR 3.71 [95% CI 2.04-6.75]), previous coronary heart disease (CHD) (OR 2.61 [1.23-5.53]), congestive heart failure (OR 4.26 [1.15-15.82]), diabetes mellitus (OR 4.02 [1.50-10.76]) and lower eGFR (OR 0.97 [0.95-0.98]). Of the 182 patients who had two hs-cTnT measurements, 12 (6.6%) had both a rise or fall of hs-cTnT with at least one elevated value, and ECG manifestations of myocardial ischemia, e.g. meeting the criteria of acute MI. Both dynamic relative change (p = 0.026) and absolute change (p = 0.032) in hs-cTnT were significantly associated with higher in-hospital mortality.

CONCLUSIONS

Established CHD and cardiovascular risk factors are associated with hs-cTnT elevation. Acute MI is likely underdiagnosed in acute ischemic stroke patients. Dynamic changes in troponin levels seem to be related to poor short-term prognosis.

Update on cardiac imaging techniques 2012

Cardiac imaging is one of the basic pillars of modern cardiology. The potential list of scenarios where cardiac imaging techniques can provide relevant information is simply endless so it is impossible to include all relevant new features of cardiac imaging published in the literature in 2012 in the limited format of a single article. We summarize the year's most relevant news on cardiac imaging, highlighting the ongoing development of myocardial deformation and 3-dimensional echocardiography techniques and the increasing use of magnetic resonance imaging and computed tomography in daily clinical practice.

High-sensitivity cardiac troponins in everyday clinical practice

High-sensitivity cardiac troponin (hs-cTn) assays are increasingly being used in many countries worldwide, however, a generally accepted definition of high-sensitivity is still pending. These assays enable cTn measurement with a high degree of analytical sensitivity with a low analytical imprecision at the low measuring range of cTn assays (coefficient of variation of < 10% at the 99^th percentile upper reference limit). One of the most important advantages of these new assays is that they allow novel, more rapid approaches to rule in or rule out acute coronary syndromes (ACSs) than with previous cTn assay generations which are still more commonly used in practice worldwide. hs-cTn is also more sensitive for the detection of myocardial damage unrelated to acute myocardial ischemia. Therefore, the increase in early diagnostic sensitivity of hs-cTn assays for ACS comes at the cost of a reduced ACS specificity, because more patients with other causes of acute or chronic myocardial injury without overt myocardial ischemia are detected than with previous cTn assays. As hs-cTn assays are increasingly being adopted in clinical practice and more hs-cTn assays are being developed, this review attempts to synthesize the available clinical data to make recommendations for their everyday clinical routine use.

Myocardial ischemia is a key factor in the management of stable coronary artery disease

Previous studies demonstrated that coronary revascularization, especially percutaneous coronary intervention (PCI), does not significantly decrease the incidence of cardiac death or myocardial infarction in patients with stable coronary artery disease. Many studies using myocardial perfusion imaging (MPI) showed that, for patients with moderate to severe ischemia, revascularization is the preferred therapy for survival benefit, whereas for patients with no to mild ischemia, medical therapy is the main choice, and revascularization is associated with increased mortality. There is some evidence that revascularization in patients with no or mild ischemia is likely to result in worsened ischemia, which is associated with increased mortality. Studies using fractional flow reserve (FFR) demonstrate that ischemia-guided PCI is superior to angiography-guided PCI, and the presence of ischemia is the key to decision-making for PCI. Complementary use of noninvasive MPI and invasive FFR would be important to compensate for each method's limitations. Recent studies of appropriateness criteria showed that, although PCI in the acute setting and coronary bypass surgery are properly performed in most patients, PCI in the non-acute setting is often inappropriate, and stress testing to identify myocardial ischemia is performed in less than half of patients. Also, some studies suggested that revascularization in an inappropriate setting is not associated with improved prognosis. Taken together, the presence and the extent of myocardial ischemia is a key factor in the management of patients with stable coronary artery disease, and coronary revascularization in the absence of myocardial ischemia is associated with worsened prognosis.

Comparison of cardiac TnI outliers using a contemporary and a high-sensitivity assay on the Abbott Architect platform

BACKGROUND

Assays for cardiac troponin (cTn) have undergone improvements in sensitivity and precision in recent years. Increased rates of outliers, however, have been reported on various cTn platforms, typically giving irreproducible, falsely higher results. We aimed to evaluate the outlier rate occurring in patients with elevated cTnI using a contemporary and high-sensitivity assay.

METHODS

All patients with elevated cTnI (up to 300 ng/L) performed over a 21-month period were assayed in duplicate. A contemporary assay (Abbott STAT Troponin-I) was used for the first part of the study and subsequently a high-sensitivity assay (Abbott STAT High-Sensitive Troponin-I) was used. Outliers exceeded a calculated critical difference (CD) (CD = z × √2 × SDAnalytical) where z = 3.5 (for probability of 0.0005) and critical outliers also were on a different side of the decision level.

RESULTS

The respective outlier and critical outlier rates were 0.22% and 0.10% for the contemporary assay (n = 4009) and 0.18% and 0.13% for the high-sensitivity assay (n = 3878). There was no significant reduction in outlier rate between the two assays (χ(2) = 0.034, P = 0.854). Fifty-six percent of outliers occurred in samples where cTn was an 'add-on' test (and was stored and refrigerated prior to assay).

CONCLUSION

Despite recent improvements in cTn methods, outliers (including critical outliers) still occur at a low rate in both a contemporary and high-sensitivity cTnI assay. Laboratory and clinical staff should be aware of this potential analytical error, particularly in samples with suboptimal sample handling such as add-on tests.

Cardioprotective effects of single oral dose of nicorandil before selective percutaneous coronary intervention

Objective:

Nicorandil, an opener of ATP-sensitive K+ channels, was used to treat angina in patients with coronary artery disease. In this study, we aim to investigate the cardioprotective effects of single oral dose of nicorandil in patients undergoing selective percutaneous coronary intervention (PCI).

Methods:

One hundred and thirty-eight patients with acute coronary syndrome undergoing PCI from July 2011 to October 2012 were randomly divided into control group (group 1, n=47), 10 mg oral nicorandil group (group 2, n=45), and 20 mg oral nicorandil group (group 3, n=46) about 2 hours before procedure, respectively. Cardiac troponin I (cTnI) levels were determined at 20 ~ 24 hours after PCI.

Results:

There was a significant difference in the rate of any cTnI elevation among the three groups (group 1: 36.17%, group 2: 20.00%, group 3: 15.22%, p=0.0176). With respect to the frequency of cTnI elevation ≥3 and 5×the upper limit of normal (ULN), there also had statistical difference among the three groups (17.02% in group 1, 8.89% in group 2, and 4.35% in group 3, respectively for cTnI elevation ≥3× ULN, p=0.0428; 12.77% in group 1, 6.67% in group 2, and 2.17% in group 3, respectively, for cTnI elevation ≥5× ULN, p=0.0487). Logistic regression analysis showed that LVEF (OR=0.915, 95% CI=0.853-0.981) and the use of nicorandil (OR=0.516, 95% CI=0.267-0.996) before PCI were independent protective factors of myocardial injury.

Conclusion:

Single oral dose of nicorandil (10 mg, 20 mg) 2 hours before the PCI procedure could decrease the incidence of peri-procedure myocardial injury and PCI-related myocardial infarction.

Usefulness of the QRS-T angle to improve long-term risk stratification of patients with acute myocardial infarction and depressed left ventricular ejection fraction

In light of the low cost, the widespread availability of the electrocardiogram, and the increasing economic burden of the health-related problems, we aimed to analyze the prognostic value of automatic frontal QRS-T angle to predict mortality in patients with left ventricular (LV) systolic dysfunction after acute myocardial infarction (AMI). About 467 consecutive patients discharged with diagnosis of AMI and with LV ejection fraction ≤40% were followed during 3.9 years (2.1 to 5.9). From them, 217 patients (47.5%) died. The frontal QRS-T angle was higher in patients who died (116.6±52.8 vs 77.9±55.1, respectively, p<0.001). The QRS-T angle value of 90° was the most accurate to predict all-cause cardiac death. After multivariate analysis, frontal QRS-T angle remained as an excellent predictor of all-cause and cardiac deaths, increasing the mortality 6% per each 10°. For the global mortality, the hazard ratio for a QRS-T angle>90° was 2.180 (1.558 to 3.050), and for the combined end point of cardiac death and appropriate implantable cardioverter defribrillator therapy, it was 2.385 (1.570 to 3.623). This independent predictive value was maintained even after adjusting by bundle brunch block, ST-elevation AMI, and its localization. In conclusion, a wide automatic frontal QRS-T angle (>90°) is a good discriminator of long-term mortality in patients with LV systolic dysfunction after an AMI. The ability to easily measure it from a standard 12-lead electrocardiogram together with its prognostic value makes the frontal QRS-T angle an attractive tool to help clinicians to improve risk stratification of those patients.

Lessons learned from the design and implementation of myocardial infarction adjudication tailored for HIV clinical cohorts

We developed, implemented, and evaluated a myocardial infarction (MI) adjudication protocol for cohort research of human immunodeficiency virus. Potential events were identified through the centralized Centers for AIDS Research Network of Integrated Clinical Systems data repository using MI diagnoses and/or cardiac enzyme laboratory results (1995-2012). Sites assembled de-identified packets, including physician notes and results from electrocardiograms, procedures, and laboratory tests. Information pertaining to the specific antiretroviral medications used was redacted for blinded review. Two experts reviewed each packet, and a third review was conducted if discrepancies occurred. Reviewers categorized probable/definite MIs as primary or secondary and identified secondary causes of MIs. The positive predictive value and sensitivity for each identification/ascertainment method were calculated. Of the 1,119 potential events that were adjudicated, 294 (26%) were definite/probable MIs. Almost as many secondary (48%) as primary (52%) MIs occurred, often as the result of sepsis or cocaine use. Of the patients with adjudicated definite/probable MIs, 78% had elevated troponin concentrations (positive predictive value = 57%, 95% confidence interval: 52, 62); however, only 44% had clinical diagnoses of MI (positive predictive value = 45%, 95% confidence interval: 39, 51). We found that central adjudication is crucial and that clinical diagnoses alone are insufficient for ascertainment of MI. Over half of the events ultimately determined to be MIs were not identified by clinical diagnoses. Adjudication protocols used in traditional cardiovascular disease cohorts facilitate cross-cohort comparisons but do not address issues such as identifying secondary MIs that may be common in persons with human immunodeficiency virus.

Analytical performance and clinical decision limit of a new release for cardiac troponin I assay

Background

Cardiac troponins (cTns) are the ‘gold standard’ biomarker for the diagnosis and prognosis of acute coronary syndrome. Analytical performance is critical at low concentrations of cTn, and many of the current assays do not meet the guideline requirement of a 10% coefficient of variation (CV) at the 99th percentile concentrations. The aim of the study was to establish if the newly released Access® AccuTnI®+3 (AccuTnI+3) cardiac troponin I assay (Beckman Coulter Inc., Brea, CA, USA) reached this objective.

Methods

All AccuTnI+3 assays were performed on UniCel® DxI800 analyzer (Beckman Coulter Inc). Limit of Blank (LoB), Limit of Detection (LoD) and Limit of Quantitation (LoQ) were determined according to Clinical Laboratory Standard Institute EP17-A and EP5-A2 protocols. The 99th percentile upper reference limit (URL) was determined by analysing serum samples from 330 apparently healthy blood donors (260 men, 70 women, age range 18–70 years, median age 36 years).

Results

LoB and LoD values were 2.6 and 12 ng/L, respectively. The 10% CV was at 18 ng/L (95% confidence interval [CI] 8–25). The 99th percentile URL was 22 ng/L (95% CI 11–34).

Conclusions

The newly released assay has improved low-end analytical performance and reaches the goal of having a total imprecision ≤10% at 99th percentile of a healthy reference population (guideline acceptable). With this assay, it is now possible to utilize the 99th percentile as decision level for myocardial injury detection.

Improved rate control reduces cardiac troponin T levels in permanent atrial fibrillation

BACKGROUND

Detectable levels of troponins are often found in serum of patients with atrial fibrillation (AF), and recent reports suggest that Tn concentrations are independently related to patient prognosis.

HYPOTHESIS

We hypothesized that treatment with common rate-reducing drugs might lower the levels of cardiac troponin T (TnT) in patients with permanent AF. We also wanted to investigate whether the different drugs would impact the Tn levels differently.

METHODS

Sixty patients were included (mean age 71 ± 9 years, 18 women) in this randomized crossover study. All patients had stable, permanent AF without ischemic heart disease or congestive heart failure. Diltiazem 360 mg, verapamil 240 mg, metoprolol 100 mg, and carvedilol 25 mg were administered once daily for 3 weeks, in a randomized sequence. At baseline and on the last day of each treatment period, TnT concentrations were measured at rest and after a maximal exercise test.

RESULTS

TnT was detectable in all patients. In 22% of the patients, TnT concentrations were above the threshold normally used for diagnosing myocardial infarction. All drugs reduced the levels of TnT significantly compared with baseline (P < 0.001 for all), but there were no significant differences between the treatments. Levels of TnT increased significantly in response to exercise testing (P < 0.001 for all).

CONCLUSIONS

Elevated TnT was demonstrated in a large proportion of stable patients with permanent AF without ischemic heart disease. A moderate reduction of heart rate by the study drugs was associated with a significant reduction in levels of TnT.

High-sensitivity troponin as an outcome predictor in acute medical admissions

BACKGROUND

Troponin estimation is increasingly performed on emergency medical admissions. We report on a high-sensitivity troponin (hscTn) assay, introduced in January 2011, and its relevance to in-hospital mortality in such patients.

AIM

To evaluate the impact of hscTn results on in-hospital mortality and the value of incorporating troponin into a predictive score of in-hospital mortality.

METHODS

All patients admitted as general medical emergencies between January 2011 and October 2012 were studied. Patients admitted under other admitting services including cardiology were excluded. We examined outcomes using generalised estimating equations, an extension of generalised linear models that permitted adjustment for correlated observations (readmissions). Margins statistics used adjusted predictions to test for interactions of key predictors while controlling for other variables using computations of the average marginal effect.

RESULTS

A total of 11 132 admission episodes were recorded. The in-hospital mortality for patients with predefined cut-offs was 1.9% when no troponin assay was requested, 5.1% when the troponin result was below the 25 ng/L 'normal' cut-off, 9.7% for a troponin result ≥25 and <50 ng/L, 14.5% for a troponin result ≥50 and <100 ng/L, 34.4% for a troponin result ≥100 and <1000 ng/L, and 58.3% for a troponin result >1000 ng/L. The OR for an in-hospital death for troponin-positive patients was 2.02 (95% CI 1.84 to 2.21); when adjusted for other mortality predictors including illness severity, the OR remained significant at 2.83 (95% CI 2.20 to 3.64). The incorporation of troponin into a multivariate logistic predictive algorithm resulted in an area under the receiver operating characteristic curve to predict an in-hospital death of 0.87 (95% CI 0.85 to 0.88).

CONCLUSIONS

An increase in troponin carries prognostic information in acutely ill medical patients; the extent of the risk conferred justifies incorporation of this information into predictive algorithms for hospital mortality.

Mortality rate in type 2 myocardial infarction: observations from an unselected hospital cohort

BACKGROUND

The classification of myocardial infarction into 5 types was introduced in 2007. The prognostic impact of this universal definition, with particular focus on type 2 myocardial infarction, has not been studied prospectively in unselected hospital patients.

METHODS

During a 1-year period, all hospitalized patients having cardiac troponin I measured were considered. The diagnosis of a myocardial infarction was according to the universal definition, and specified criteria were used in the classification of type 2 myocardial infarction. Follow-up was at least 1 year, with mortality as the end point.

RESULTS

A total of 3762 consecutive patients were studied, of whom 488 (13%) had a myocardial infarction. In 119 patients a type 2 myocardial infarction was diagnosed. After a median of 2.1 years (interquartile range, 1.6-2.5 years), 150 patients had died, with a mortality rate of 49% (58/119) in those with type 2 myocardial infarction and 26% (92/360) in those with type 1 myocardial infarction (P < .0001). In a multivariable Cox regression analysis the following variables were independently associated with mortality: current or prior smoker, high age, prior myocardial infarction, type 2 myocardial infarction, hypercholesterolemia, high p-creatinine, and diabetes mellitus. The multivariable-adjusted hazard ratio for type 2 myocardial infarction was 2.0 (95% confidence interval, 1.3-3.0). With shock as the only exception, mortality was independent of the triggering conditions leading to type 2 myocardial infarction.

CONCLUSIONS

Mortality in patients with type 2 myocardial infarction is high, reaching approximately 50% after 2 years. Further descriptive and survival studies are needed to improve the scientific evidence on which treatment of type 2 myocardial infarction is based.

Incidence and predictors of early left ventricular thrombus after ST-elevation myocardial infarction in the contemporary era of primary percutaneous coronary intervention

The aim of this study was to define the incidence of left ventricular thrombus (LVT) and its predictors in the contemporary era of primary percutaneous intervention (pPCI) and contrast echocardiography. We retrospectively analyzed 1,059 patients presenting with ST-elevation myocardial infarction (STEMI) to our tertiary cardiac center and treated with pPCI. Preprocedural pharmacology and procedural technique (including access route, the use of drug-eluting stents, and thrombectomy) were at the operators' discretion. Transthoracic echocardiography was performed before discharge; echo contrast agent was used when appropriate. LVT was detected in 42 subjects (4%). There were no significant differences in baseline demographics or pre-PCI clinical features between the 2 groups. Post-treatment, mean ejection fraction (EF) in patients with LVT was 35±8.4% and in those without LVT was 47±10%, p<0.001. Thirty-seven patients (88%) in the LVT group presented with an anterior STEMI versus 471 patients (42%) in the without LVT group (p<0.001). Apical akinesis was noted in all patients with LVT irrespective of the principal location of the MI. Multivariate analysis predictors of LVT were reduced EF, anterior site of MI, and the use of platelet glycoprotein IIb/IIIa inhibitors. After diagnosis of LVT, patients were treated with warfarin for 3 to 6 months. No significant difference in mortality was detectable at discharge between the 2 groups. In conclusion, in the contemporary era of pPCI, the incidence of LVT in patients with STEMI is significantly lower than that of the previous (thrombolysis) literature. The early presence of LVT is more likely in patients with anterior STEMI (involving the apex) and reduced EF.

Scar tissue-guided left ventricular lead placement for cardiac resynchronization therapy in patients with ischemic cardiomyopathy: an acute pressure-volume loop study

BACKGROUND

Response to cardiac resynchronization therapy (CRT) is hampered by the extent and location of left ventricular (LV) scar tissue. It is commonly advised to avoid scar tissue while placing the LV lead. However, whether individual patients benefit from this strategy remains unclear.

METHODS

Thirty-two CRT candidates with ischemic cardiomyopathy were enrolled from 2 successive clinical trials (TBS and E-pot study). Magnetic resonance imaging with late contrast enhancement was performed to assess location, degree and transmurality of LV scar tissue. Patients underwent invasive pressure-volume loop measurements to assess acute LV pump function changes during pacing at posterolateral (PL) and anterolateral LV sites.

RESULTS

In the study population (26 [81%] men, ejection fraction [EF] 22% ± 8%, QRS 149 ± 20 milliseconds), baseline mean stroke work (SW) and dP/dtmax were 4.4 ± 2.2 L∙mmHg and 849 ± 212 mmHg/s, respectively. The extent of scar tissue was inversely related to the acute increase in SW during pacing (R = -0.53, P = .002). Stimulating PL scar tissue resulted in deterioration of pump function (∆SW -17% ± 17%, P = .018), whereas pacing PL viable tissue led to an increase in pump function (∆SW +62% ± 51%, P < .001). Switching from pacing at the location of scar tissue, irrespective of the scar location, to viable tissue showed a significant increase in SW (-8% ± 20% vs +20 ± 40, P = .004).

CONCLUSIONS

The extent of LV scar tissue is inversely related to acute pump function improvement during CRT. Pacing at the location of (transmural) scar tissue at any site of the LV will generally deteriorate LV pump function. Placing the LV lead over viable myocardium significantly improves pump function as compared with pacing at the location of scar tissue in patients with ischemic cardiomyopathy.

At-admission risk stratification for in-hospital life-threatening ventricular arrhythmias and death in non-ST elevation myocardial infarction patients

AIMS

Identification of patients with non-ST elevation acute myocardial infarction (NSTEMI) at higher risk of in-hospital life-threatening ventricular arrhythmias (LT-VA) and death is crucial for determining appropriate levels of care/monitoring during hospitalisation. We assessed predictors of in-hospital LT-VA and all-cause mortality in a consecutive series of NSTEMI patients.

METHODS AND RESULTS

We prospectively studied 1325 consecutive patients (69.7% males, median age 70 (61-79) years) presenting with NSTEMI and undergoing continuous electrocardiographic monitoring. The primary study end-point was the occurrence of spontaneous (unrelated to coronary interventions) in-hospital LT-VA, including sustained ventricular tachycardia and ventricular fibrillation; the secondary end-point was in-hospital mortality from all causes. Of 1325 patients, 21 (1.5%) experienced LT-VA and 62 (4.7%) died from either arrhythmias (n=1) or other causes (n=61). Seven of the 20 patients who survived LT-VA subsequently died of heart failure. Independent predictors of in-hospital LT-VA were the Global Registry of Acute Coronary Events (GRACE) score >140 (odds ratio (OR)=7.5; 95% confidence interval (CI) 1.7-33.3; p=0.008) and left ventricular ejection fraction (LV-EF)<35% (OR=4.1; 95% CI 1.7-10.3; p=0.002). GRACE score >140 (OR=14.6; 95% CI 3.4-62) and LV-EF <35% (OR=4.4; 95% CI 1.9-10) also predicted in-hospital all-cause death. The cumulative probability of in-hospital LT-VA and death was respectively 9.2% and 23% in the 98 (7.4%) patients with GRACE score >140 and LV-EF<35%, while it was respectively 0.2% and 0% among the 627 (47.3%) with GRACE score ≤140 and LV-EF ≥35%.

CONCLUSIONS

Simple risk stratification at admission based on GRACE score and echocardiographic LV-EF allows early identification of NSTEMI patients at higher risk of both in-hospital LT-VA and all-cause mortality.

Compliance of pharmacological treatment for non-ST-elevation acute coronary syndromes with contemporary guidelines: influence on outcomes

BACKGROUND

Although the proven efficacy of evidence-based therapy in patients with cardiovascular diseases, the recommendations are not always instituted. We aimed to analyse the compliance of non-ST-elevation acute coronary syndrome (NSTE-ACS) patients with treatment guidelines and to assess the impact of these measures in hospital death during the index hospitalization.

POPULATION AND METHODS

All consecutive patients (pts) included in the Portuguese Registry on Acute Coronary Syndromes (ProACS) between January 1, 2002 and August 31, 2011 were analysed. Compliance with Guidelines for the management of NSTE-ACS was evaluated with a 6-point therapeutic score (ThSc), comprising the treatment with: aspirin, clopidogrel, heparin, beta-blocker, angiotensin-converting enzyme inhibitor and statin. One point was assigned for each drug prescribed and zero if not given. The total therapeutic compliance was defined as ThSc =6 points.

RESULTS

The final analysis comprised 14,276 pts (67.1% male; mean age 67.6±12.3 years), most of them admitted with non-ST elevation myocardial infarction (77.4%). The mean value of ThSc was 4.9±1.1 and total compliance occurred in 36.7% pts. Centres with percutaneous coronary intervention (PCI) capacity had a statistically significant higher ThSc (5.0±1.0 vs. 4.8±1.1, P<0.001) and were associated with higher total compliance [OR 1.53, 95% confidence intervals (CI), 1.42-1.65, P<0.001]. In-hospital mortality was 2.4% (354 deaths). Compared to pts who died, the survivors had a higher ThSc (4.9±1.1 vs. 4.2±1.3, P<0.001) and this score was independently associated with lower risk of in-hospital mortality (OR 0.70, 95% CI, 0.64-0.77, P<0.001). Receiver operating characteristics curve analysis showed a good accuracy of ThSc for the occurrence of in-hospital mortality with the area under the curve (AUC) 0.82 (95% CI, 0.80-0.84, P<0.001), sensitivity 71.6% and specificity 78.0%. Age, peripheral artery disease, Killip-Kimball class >I, electrocardiogram (ECG) with ST-segment depression and positive troponin were other independent predictors of in-hospital mortality.

CONCLUSIONS

In the present study, patients with NSTE-ACS who received medications recommended by guidelines had better in-hospital outcomes. These findings highlight the need to clarify the clinical recommendations and to develop approaches for quality improvement in this subset of patients.

Current results of endovascular repair of thoraco-abdominal aneurysms†

OBJECTIVES

Fenestrated and branch endografts represent a totally endovascular solution for high-risk patients with atherosclerotic thoraco-abdominal aortic aneurysms (TAAAs). This study reports the early outcome of endovascular TAAA repair.

METHODS

Interrogation of a prospective database of consecutive patients who underwent endovascular repair (EVAR) for TAAA between June 2007 and October 2012.

RESULTS

Sixty-two high-risk patients (55 men; median age 72, range 54-84 years) underwent fenestrated (n = 39) or branch (n = 23) EVAR for non-ruptured TAAA [extent I-III (n = 26) and IV (n = 36)]. Twenty patients had undergone 22 previous aortic procedures. A total of 221 target vessels (coeliac 50, superior mesenteric 61, renal 106, left subclavian 1 and hypogastric 3) were preserved with scallops (n = 17), fenestrations (n = 140) or branches (n = 62) and 201 of these vessels were stent-grafted (coeliac 34, superior mesenteric 58, renal 105, left subclavian 1 and hypogastric 3). The 30-day mortality was 1.6% (n = 1) and one further patient died on postoperative day 62 from respiratory complications. Spinal cord injury (SCI) developed in 5 (8%) patients (3 women and 2 men). Two patients required temporary renal replacement therapy and a further two commenced planned postoperative dialysis.

CONCLUSIONS

In high-risk patients with TAAA, fenestrated and branch EVAR is associated with low early mortality and requirement for renal support, but the risk of SCI is not insignificant despite the use of cerebrospinal fluid drainage and blood pressure manipulation. Our current practice is to stage the repair of extent I-III aneurysms and this has significantly reduced the incidence of SCI.

Reprint of "Decline in platelet count and long-term post-PCI ischemic events: implication of the intra-aortic balloon pump"

AIMS

Thrombocytopenia (TC) following a percutaneous coronary intervention (PCI) has been associated not only with hemorrhagic, but also with ischemic outcomes. The purpose of this study was to re-examine the relationship of TC with ischemic events at a 1-year follow-up, and investigate the possible associations.

METHODS AND RESULTS

We studied a real-world, unselected population of ischemic patients undergoing PCI, totaling 861 patients-year, and divided into two groups: with TC (delta platelet count ≥25% from baseline to post-PCI during the hospital admission) and without TC. Compared with patients without TC, patients with TC had a higher and earlier incidence of both hemorrhagic and ischemic events. In them, the use of intra-aortic balloon pump (IABP) was ten-fold higher. In Kaplan-Meier curves assessing the contribution of both TC and IABP to outcome, IABP was a univariate detrimental factor additive to the role of TC. In a forced Cox model, the relative decline (delta) in platelet count (p=0.05) and the use of IABP (p=0.0001) were both associated with ischemic outcomes. After excluding all patients with IABP, the delta platelet count was no longer significantly associated with ischemic outcomes (p=0.66). After excluding all patients with shock and all those who undergone thrombolysis, there was still a relationship (p=0.0042) between the delta platelet count and ischemic events.

CONCLUSIONS

In this patient population the use of IABP, but not thrombocytopenia per se, is a possible primary cause of worse ischemic outcomes.

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Zwolle risk score predicts contrast-induced acute kidney injury in STEMI patients undergoing PCI

OBJECTIVE

Contrast-induced acute kidney injury (CI-AKI) is a common complication in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). The Mehran risk score was defined originally in elective PCI and may be predictive of CI-AKI. The aim of the present study was to investigate whether the Zwolle score predicts CI-AKI in patients with acute STEMI undergoing primary PCI.

PATIENTS AND METHODS

We analyzed the data of 314 consecutive patients (mean age 56.3 ± 11.4 years) with acute STEMI undergoing primary PCI. The study population was divided into two groups according to CI-AKI development. The Mehran score, Zwolle score, baseline characteristics, and in-hospital outcomes were recorded.

RESULTS

Patients with CI-AKI had higher Mehran and Zwolle scores. In a receiver operating characteristic (ROC) curve analysis, high area under the curve (AUC) values were determined for Zwolle and Mehran scores (0.85 and 0.79, respectively) for CI-AKI development. A Zwolle score greater than  2 predicted CI-AKI with a sensitivity of 76.3 % and a specificity of 75.4 %. A Mehran score greater than 5 predicted CI-AKI with a sensitivity of 71.1 % and a specificity of 73.6 %.

CONCLUSION

Zwolle score predicts CI-AKI slightly better than the Mehran score in patients with STEMI undergoing primary PCI. This simple score can be used at the catheterization laboratory for risk stratification for the development of CI-AKI.

Alterations in plasma lecithin:cholesterol acyltransferase and myeloperoxidase in acute myocardial infarction: implications for cardiac outcome

BACKGROUND

The cholesterol esterifying enzyme, lecithin:cholesterol acyltransferase (LCAT), plays a key role in HDL maturation and remodeling. Myeloperoxidase (MPO) may compromise LCAT enzymatic activity. We tested the extent to which plasma LCAT activity is altered in acute myocardial infarction (MI) in conjunction with abnormal MPO levels. We also assessed the impact of LCAT and MPO on newly developed major adverse cardiovascular events (MACE).

METHODS

Two-hundred one consecutive patients referred for acute chest pain of whom 134 had MI (95 with ST-elevation) participated. Forty-five new MACE were ascertained during 1203 (range 13-1745) days of follow-up among 185 patients. Plasma LCAT activity was measured using an exogenous substrate assay. MPO mass was assayed by chemiluminescent microparticle immunoassay.

RESULTS

Plasma LCAT activity was decreased by 15%, coinciding with 7-fold increased MPO levels in acute MI patients vs. patients with non-cardiac chest pain (p < 0.001 for both; correlation: r = -0.343, p < 0.001). MI at admission was associated independently with both lower plasma LCAT activity and higher MPO (age- and sex-adjusted odds ratio per 1 SD increment: 0.46 (95% CI, 0.31-0.68), p < 0.001 and 7.58 (95% CI, 3.34-17.11), p < 0.001, respectively). In an analysis with LCAT and MPO together these associations were modestly attenuated. MPO mass (hazard ratio: 1.59 (95% CI, 1.15-2.19), p = 0.004), but not LCAT activity (hazard ratio: 0.87 (95% CI, 0.65-1.19), p = 0.39), predicted newly manifest MACE.

CONCLUSION

In acute MI patients, plasma LCAT activity is decreased coinciding with increased MPO levels. Higher MPO but not lower LCAT activity prospectively predicts adverse cardiac outcome.

Weekly and 90-minute biological variations in cardiac troponin T and cardiac troponin I in hemodialysis patients and healthy controls

BACKGROUND

Myocardial infarction (MI) is diagnosed by the finding of a single cardiac troponin value above the 99th percentile and a significant time-dependent change in cardiac troponin concentration. The aim of this study was to determine the 90-min and weekly biological variations, the reference change value (RCV), and the index of individuality (II) of high-sensitivity cardiac troponin T (hs-cTnT) (Roche Diagnostics) and hs-cTnI (Abbott Diagnostics) in patients receiving hemodialysis (HD) and in healthy individuals.

METHOD

Blood samples were collected from 19 HD patients (on an HD-free day) and 20 healthy individuals at 90-min intervals over a 6-h period (between 08:30 and 14:30) and before the midweek HD treatment for 10 weeks. The within-person variation (CVi), between-person variation, RCV, and II were calculated.

RESULTS

During the 6-h sampling period, the concentrations of hs-cTnT (both groups) and hs-cTnI (HD patients only) decreased on average by 0.8% to 1.7% per hour, respectively. These declining trends were included in the calculation of a 90-min asymmetric RCV: -8%/+5% in HD patients (hs-cTnT), -18%/+21% in HD patients (hs-cTnI), -27%/+29% in healthy individuals (hs-cTnT), and -39%/+64% in healthy individuals (hs-cTnI). The II was low in both groups for both assays. The weekly CVi values were approximately 8% (hs-cTnT) and 15% (hs-cTnI) in both groups.

CONCLUSIONS

When using a cardiac troponin change of 20%-50% to diagnose an MI, the false-positive rate is likely to be lower for the hs-cTnT assay than for the hs-cTnI assay. The low II suggests that use of a diagnostic cutoff value can be omitted.