International Validation of the Canadian Syncope Risk Score : A Cohort Study.

BACKGROUND: The Canadian Syncope Risk Score (CSRS) was developed to predict 30-day serious outcomes not evident during emergency department (ED) evaluation. OBJECTIVE: To externally validate the CSRS and compare it with another validated score, the Osservatorio Epidemiologico della Sincope nel Lazio (OESIL) score. DESIGN: Prospective cohort study. SETTING: Large, international, multicenter study recruiting patients in EDs in 8 countries on 3 continents. PARTICIPANTS: Patients with syncope aged 40 years or older presenting to the ED within 12 hours of syncope. MEASUREMENTS: Composite outcome of serious clinical plus procedural events (primary outcome) and the primary composite outcome excluding procedural interventions (secondary outcome). RESULTS: Among 2283 patients with a mean age of 68 years, the primary composite outcome occurred in 7.2%, and the composite outcome excluding procedural interventions occurred in 3.1% at 30 days. Prognostic performance of the CSRS was good for both 30-day composite outcomes and better compared with the OESIL score (area under the receiver-operating characteristic curve [AUC], 0.85 [95% CI, 0.83 to 0.88] vs. 0.74 [CI, 0.71 to 0.78] and 0.80 [CI, 0.75 to 0.84] vs. 0.69 [CI, 0.64 to 0.75], respectively). Safety of triage, as measured by the frequency of the primary composite outcome in the low-risk group, was higher using the CSRS (19 of 1388 [0.6%]) versus the OESIL score (17 of 1104 [1.5%]). A simplified model including only the clinician classification of syncope (cardiac syncope, vasovagal syncope, or other) variable at ED discharge-a component of the CSRS-achieved similar discrimination as the CSRS (AUC, 0.83 [CI, 0.80 to 0.87] for the primary composite outcome). LIMITATION: Unable to disentangle the influence of other CSRS components on clinician classification of syncope at ED discharge. CONCLUSION: This international external validation of the CSRS showed good performance in identifying patients at low risk for serious outcomes outside of Canada and superior performance compared with the OESIL score. However, clinician classification of syncope at ED discharge seems to explain much of the performance of the CSRS in this study. The clinical utility of the CSRS remains uncertain. PRIMARY FUNDING SOURCE: Swiss National Science Foundation & Swiss Heart Foundation.

B-Type Natriuretic Peptides and Cardiac Troponins for Diagnosis and Risk-Stratification of Syncope.

BACKGROUND: The utility of BNP (B-type natriuretic peptide), NT-proBNP (N-terminal proBNP), and hs-cTn (high-sensitivity cardiac troponin) concentrations for diagnosis and risk-stratification of syncope is incompletely understood. METHODS: We evaluated the diagnostic and prognostic accuracy of BNP, NT-proBNP, hs-cTnT, and hs-cTnI concentrations, alone and against those of clinical assessments, in patients >45-years old presenting with syncope to the emergency department in a prospective diagnostic multicenter study. BNP, NT-proBNP, hs-cTnT and hs-cTnI concentrations were measured in a blinded fashion. Cardiac syncope, as adjudicated by 2 physicians based on all information available including cardiac work-up and 1-year follow-up, was the diagnostic end point. EGSYS (Evaluation of Guidelines in Syncope Study), a syncope-specific diagnostic score, served as the diagnostic comparator. Death and major adverse cardiac events at 30 and 720 days were the prognostic end points. Major adverse cardiac events were defined as death, cardiopulmonary resuscitation, life-threatening arrhythmia, implantation of pacemaker/implantable cardioverter defibrillator, acute myocardial infarction, pulmonary embolism, stroke/transient ischemic attack, intracranial bleeding, or valvular surgery. ROSE (Risk Stratification of Syncope in the Emergency Department), OESIL (Osservatorio Epidemiologico della Sincope nel Lazio), SFSR (San Fransisco Syncope Rule), and CSRS (Canadian Syncope Risk Score) served as the prognostic comparators. RESULTS: Among 1538 patients eligible for diagnostic assessment, cardiac syncope was the adjudicated diagnosis in 234 patients (15.2%). BNP, NT-proBNP, hs-cTnT, and hs-cTnI were significantly higher in cardiac syncope versus other causes (P<0.01). The diagnostic accuracy for cardiac syncope, as quantified by the area under the curve, was 0.77 to 0.78 (95% CI, 0.74-0.81) for all 4 biomarkers, and superior to EGSYS (area under the curve, 0.68 [95%-CI 0.65-0.71], P<0.001). Combining BNP/NT-proBNP with hs-cTnT/hs-cTnI further improved diagnostic accuracy to an area under the curve of 0.81 (P<0.01). BNP, NT-proBNP, hs-cTnT, and hs-cTnI cut-offs, achieving predefined thresholds for sensitivity and specificity (95%), allowed for rule-in or rule-out of ≈30% of all patients. A total of 450 major adverse cardiac events occurred during follow-up. The prognostic accuracy of BNP, NT-proBNP, hs-cTnI, and hs-cTnT for major adverse cardiac events was moderate-to-good (area under the curve, 0.75-0.79), superior to ROSE, OESIL, and SFSR, and inferior to CSRS. CONCLUSIONS: BNP, NT-proBNP, hs-cTnT, and hs-cTnI concentrations provide useful diagnostic and prognostic information in emergency department patients with syncope. CLINICAL TRIAL REGISTRATION: URL: https://www. CLINICALTRIALS: gov. Unique identifier: NCT01548352.

Incidence, characteristics, determinants, and prognostic impact of recurrent syncope.

AIMS: The aim of this study is to characterize recurrent syncope, including sex-specific aspects, and its impact on death and major adverse cardiovascular events (MACE). METHODS AND RESULTS: We characterized recurrent syncope in a large international multicentre study, enrolling patients ≥40 years presenting to the emergency department (ED) with a syncopal event within the last 12 h. Syncope aetiology was centrally adjudicated by two independent cardiologists using all information becoming available during syncope work-up and long-term follow-up. Overall, 1790 patients were eligible for this analysis. Incidence of recurrent syncope was 20% [95% confidence interval (CI) 18-22%] within the first 24 months. Patients with an adjudicated final diagnosis of cardiac syncope (hazard ratio (HR) 1.50, 95% CI 1.11-2.01) or syncope with an unknown aetiology even after central adjudication (HR 2.11, 95% CI 1.54-2.89) had an increased risk for syncope recurrence. Least Absolute Shrinkage and Selection Operator regression fit on all patient information available early in the ED identified >3 previous episodes of syncope as the only independent predictor for recurrent syncope (HR 2.13, 95% CI 1.64-2.75). Recurrent syncope carried an increased risk for death (HR 1.87, 95% CI 1.26-2.77) and MACE (HR 2.69, 95% CI 2.02-3.59) over 24 months of follow-up, however, with a time-dependent effect. These findings were confirmed in a sensitivity analysis excluding patients with syncope recurrence or MACE before or during ED evaluation. CONCLUSION: Recurrence rates of syncope are substantial and vary depending on syncope aetiology. Importantly, recurrent syncope carries a time-dependent increased risk for death and MACE. TRIAL REGISTRATION: BAsel Syncope EvaLuation (BASEL IX, ClinicalTrials.gov registry number NCT01548352).

Combining High-Sensitivity Cardiac Troponin I and Cardiac Troponin T in the Early Diagnosis of Acute Myocardial Infarction.

BACKGROUND: Combining 2 signals of cardiomyocyte injury, cardiac troponin I (cTnI) and T (cTnT), might overcome some individual pathophysiological and analytical limitations and thereby increase diagnostic accuracy for acute myocardial infarction with a single blood draw. We aimed to evaluate the diagnostic performance of combinations of high-sensitivity (hs) cTnI and hs-cTnT for the early diagnosis of acute myocardial infarction. METHODS: The diagnostic performance of combining hs-cTnI (Architect, Abbott) and hs-cTnT (Elecsys, Roche) concentrations (sum, product, ratio, and a combination algorithm) obtained at the time of presentation was evaluated in a large multicenter diagnostic study of patients with suspected acute myocardial infarction. The optimal rule-out and rule-in thresholds were externally validated in a second large multicenter diagnostic study. The proportion of patients eligible for early rule-out was compared with the European Society of Cardiology 0/1 and 0/3 hour algorithms. RESULTS: Combining hs-cTnI and hs-cTnT concentrations did not consistently increase overall diagnostic accuracy as compared with the individual isoforms. However, the combination improved the proportion of patients meeting criteria for very early rule-out. With the European Society of Cardiology 2015 guideline recommended algorithms and cut-offs, the proportion meeting rule-out criteria after the baseline blood sampling was limited (6% to 24%) and assay dependent. Application of optimized cut-off values using the sum (9 ng/L) and product (18 ng2/L2) of hs-cTnI and hs-cTnT concentrations led to an increase in the proportion ruled-out after a single blood draw to 34% to 41% in the original (sum: negative predictive value [NPV] 100% [95% confidence interval (CI), 99.5% to 100%]; product: NPV 100% [95% CI, 99.5% to 100%]) and in the validation cohort (sum: NPV 99.6% [95% CI, 99.0-99.9%]; product: NPV 99.4% [95% CI, 98.8-99.8%]). The use of a combination algorithm (hs-cTnI <4 ng/L and hs-cTnT <9 ng/L) showed comparable results for rule-out (40% to 43% ruled out; NPV original cohort 99.9% [95% CI, 99.2-100%]; NPV validation cohort 99.5% [95% CI, 98.9-99.8%]) and rule-in (positive predictive value [PPV] original cohort 74.4% [95% Cl, 69.6-78.8%]; PPV validation cohort 84.0% [95% Cl, 79.7-87.6%]). CONCLUSIONS: New strategies combining hs-cTnI and hs-cTnT concentrations may significantly increase the number of patients eligible for very early and safe rule-out, but do not seem helpful for the rule-in of acute myocardial infarction. CLINICAL TRIAL REGISTRATION: URL (APACE): https://www.clinicaltrial.gov . Unique identifier: NCT00470587. URL (ADAPT): www.anzctr.org.au . Unique identifier: ACTRN12611001069943.

Impact of age on the performance of the ESC 0/1h-algorithms for early diagnosis of myocardial infarction.

Aims: We aimed to evaluate the impact of age on the performance of the European Society of Cardiology (ESC) 0/1h-algorithms and to derive and externally validate alternative cut-offs specific to older patients. Methods and results: We prospectively enrolled patients presenting to the emergency department (ED) with symptoms suggestive of acute myocardial infarction in three large diagnostic studies. Final diagnoses were adjudicated by two independent cardiologists. High-sensitivity cardiac troponin (hs-cTn) T and I concentrations were measured at presentation and after 1 h. Patients were stratified according to age [<55 years (young), ≥55 to <70 years (middle-age), ≥70 years (old)]. Rule-out safety of the ESC hs-cTnT 0/1h-algorithm was very high in all age-strata: sensitivity 100% [95% confidence interval (95% CI) 94.9-100] in young, 99.3% (95% CI 96.0-99.9) in middle-age, and 99.3% (95% CI 97.5-99.8) in old patients. Accuracy of rule-in decreased with age: specificity 97.0% (95% CI 95.8-97.9) in young, 96.1% (95% CI 94.5-97.2) in middle-age, and 92.7% (95% CI 90.7-94.3) in older patients. Triage efficacy decreased with increasing age (young 93%, middle-age 80%, old 55%, P < 0.001). Similar results were found for the ESC hs-cTnT 0/1h-algorithm. Alternative, slightly higher cut-off concentrations optimized for older patients maintained very high safety of rule-out, increased specificity of rule-in (P < 0.01), reduced overall efficacy for hs-cTnT (P < 0.01), while maintaining efficacy for hs-cTnI. Findings were confirmed in two validation cohorts (n = 2767). Conclusion: While safety of the ESC 0/1h-algorithms remained very high, increasing age significantly reduced overall efficacy and the accuracy of rule-in. Alternative slightly higher cut-off concentrations may be considered for older patients, particularly if using hs-cTnI. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00470587, number NCT00470587 and NCT02355457 (BACC).

Direct Comparison of Cardiac Myosin-Binding Protein C With Cardiac Troponins for the Early Diagnosis of Acute Myocardial Infarction.

BACKGROUND: Cardiac myosin-binding protein C (cMyC) is a cardiac-restricted protein that is more abundant than cardiac troponins (cTn) and is released more rapidly after acute myocardial infarction (AMI). We evaluated cMyC as an adjunct or alternative to cTn in the early diagnosis of AMI. METHODS: Unselected patients (N=1954) presenting to the emergency department with symptoms suggestive of AMI, concentrations of cMyC, and high-sensitivity (hs) and standard-sensitivity cTn were measured at presentation. The final diagnosis of AMI was independently adjudicated using all available clinical and biochemical information without knowledge of cMyC. The prognostic end point was long-term mortality. RESULTS: Final diagnosis was AMI in 340 patients (17%). Concentrations of cMyC at presentation were significantly higher in those with versus without AMI (median, 237 ng/L versus 13 ng/L, P<0.001). Discriminatory power for AMI, as quantified by the area under the receiver-operating characteristic curve (AUC), was comparable for cMyC (AUC, 0.924), hs-cTnT (AUC, 0.927), and hs-cTnI (AUC, 0.922) and superior to cTnI measured by a contemporary sensitivity assay (AUC, 0.909). The combination of cMyC with hs-cTnT or standard-sensitivity cTnI (but not hs-cTnI) led to an increase in AUC to 0.931 (P<0.0001) and 0.926 (P=0.003), respectively. Use of cMyC more accurately classified patients with a single blood test into rule-out or rule-in categories: Net Reclassification Improvement +0.149 versus hs-cTnT, +0.235 versus hs-cTnI (P<0.001). In early presenters (chest pain <3 h), the improvement in rule-in/rule-out classification with cMyC was larger compared with hs-cTnT (Net Reclassification Improvement +0.256) and hs-cTnI (Net Reclassification Improvement +0.308; both P<0.001). Comparing the C statistics, cMyC was superior to hs-cTnI and standard sensitivity cTnI (P<0.05 for both) and similar to hs-cTnT at predicting death at 3 years. CONCLUSIONS: cMyC at presentation provides discriminatory power comparable to hs-cTnT and hs-cTnI in the diagnosis of AMI and may perform favorably in patients presenting early after symptom onset. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Direct Comparison of 4 Very Early Rule-Out Strategies for Acute Myocardial Infarction Using High-Sensitivity Cardiac Troponin I.

BACKGROUND: Four strategies for very early rule-out of acute myocardial infarction using high-sensitivity cardiac troponin I (hs-cTnI) have been identified. It remains unclear which strategy is most attractive for clinical application. METHODS: We prospectively enrolled unselected patients presenting to the emergency department with symptoms suggestive of acute myocardial infarction. The final diagnosis was adjudicated by 2 independent cardiologists. Hs-cTnI levels were measured at presentation and after 1 hour in a blinded fashion. We directly compared all 4 hs-cTnI-based rule-out strategies: limit of detection (LOD, hs-cTnI<2 ng/L), single cutoff (hs-cTnI<5 ng/L), 1-hour algorithm (hs-cTnI<5 ng/L and 1-hour change<2 ng/L), and the 0/1-hour algorithm recommended in the European Society of Cardiology guideline combining LOD and 1-hour algorithm. RESULTS: Among 2828 enrolled patients, acute myocardial infarction was the final diagnosis in 451 (16%) patients. The LOD approach ruled out 453 patients (16%) with a sensitivity of 100% (95% confidence interval [CI], 99.2%-100%), the single cutoff 1516 patients (54%) with a sensitivity of 97.1% (95% CI, 95.1%-98.3%), the 1-hour algorithm 1459 patients (52%) with a sensitivity of 98.4% (95% CI, 96.8%-99.2%), and the 0/1-hour algorithm 1463 patients (52%) with a sensitivity of 98.4% (95% CI, 96.8%-99.2%). Predefined subgroup analysis in early presenters (≤2 hours) revealed significantly lower sensitivity (94.2%, interaction P=0.03) of the single cutoff, but not the other strategies. Two-year survival was 100% with LOD and 98.1% with the other strategies (P<0.01 for LOD versus each of the other strategies). CONCLUSIONS: All 4 rule-out strategies balance effectiveness and safety equally well. The single cutoff should not be applied in early presenters, whereas the 3 other strategies seem to perform well in this challenging subgroup. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00470587.

Effect of Acute Coronary Syndrome Probability on Diagnostic and Prognostic Performance of High-Sensitivity Cardiac Troponin.

BACKGROUND: There is concern that high-sensitivity cardiac troponin (hs-cTn) may have low diagnostic accuracy in patients with low acute coronary syndrome (ACS) probability. METHODS: We prospectively stratified patients presenting with acute chest discomfort to the emergency department (ED) into 3 groups according to their probability for ACS as assessed by the treating ED physician using a visual analog scale: ≤10%, 11% to 79%, and ≥80%, reviewing all information available at 90 min. hs-cTnT and hs-cTnI concentrations were determined in a blinded fashion. Two independent cardiologists adjudicated the final diagnosis. RESULTS: Among 3828 patients eligible for analysis, 1189 patients had low (≤10%) probability for ACS. The incidence of non-ST-segment elevation myocardial infarction (NSTEMI) increased from 1.3% to 12.2% and 54.8% in patients with low, intermediate, and high ACS probability, respectively. The positive predictive value of hs-cTnT and hs-cTnI was low in patients with low ACS probability and increased with the incidence of NSTEMI, whereas the diagnostic accuracy of hs-cTnT and hs-cTnI for NSTEMI as quantified by the area under the curve (AUC) was very high and comparable among all 3 strata, e.g., AUC hs-cTnI, 0.96 (95% CI, 0.94-0.97); 0.87 (95% CI, 0.85-0.89); and 0.89 (95% CI, 0.87-0.92), respectively. Findings were validated using bootstrap analysis as an alternative methodology to define ACS probability. Similarly, higher hs-cTnT/I concentrations independently predicted all-cause mortality within 2 years (e.g., hs-cTnT hazard ratio, 1.39; 95% CI, 1.27-1.52), irrespective of ACS probability. CONCLUSIONS: Diagnostic and prognostic accuracy and utility of hs-cTnT and hs-cTnI remain high in patients with acute chest discomfort and low ACS probability.ClinicalTrials.gov Identifier: NCT00470587.

Direct Comparison of 2 Rule-Out Strategies for Acute Myocardial Infarction: 2-h Accelerated Diagnostic Protocol vs 2-h Algorithm.

BACKGROUND: We compared 2 high-sensitivity cardiac troponin (hs-cTn)-based 2-h strategies in patients presenting with suspected acute myocardial infarction (AMI) to the emergency department (ED): the 2-h accelerated diagnostic protocol (2h-ADP) combining hs-cTn, electrocardiogram, and a risk score, and the 2-h algorithm exclusively based on hs-cTn concentrations and their absolute changes. METHODS: Analyses were performed in 2 independent diagnostic cohorts [European Advantageous Predictors of Acute Coronary Syndrome Evaluation (APACE) study, Australian-New Zealand 2-h Accelerated Diagnostic Protocol to Assess patients with chest Pain symptoms using contemporary Troponins as the only biomarker (ADAPT) study] employing hs-cTnT (Elecsys) and hs-cTnI (Architect). The final diagnosis was adjudicated by 2 independent cardiologists. RESULTS: AMI was the final diagnosis in 16.5% (95% CI, 14.6%-18.6%) of the 1372 patients in APACE, and 12.6% (95% CI, 10.7%-14.7%) of 1153 patients in ADAPT. The negative predictive value (NPV) and sensitivity for AMI were very high and comparable with both strategies using either hs-cTnT or hs-cTnI in both cohorts (all statistical comparisons nonsignificant). The percentage of patients triaged toward rule-out was significantly lower with the 2h-ADP (36%-43%) vs the 2-h algorithm (55%-68%) with both assays and in both cohorts (P < 0.001). The sensitivity of the 2h-ADP was higher for 30-day major adverse cardiovascular events. CONCLUSIONS: Both algorithms provided very high and comparable safety as quantified by the NPV and sensitivity for AMI and major adverse cardiac events (MACE) at 30 days in patients triaged toward rule-out, although sensitivity for MACE at 30 days was lower with both algorithms in cohort 2. Although the 2-h algorithm was more efficacious, not all patients ruled out for AMI by this algorithm were appropriate candidates for early discharge. The 2h-ADP seems superior in the selection of patients for early discharge from the ED. CLINICAL TRIAL REGISTRATION: APACE: http://clinicaltrials.gov/show/NCT00470587ADAPT: Australia-New Zealand Clinical Trials Registry ACTRN12611001069943.

Rapidly regulating platelet activity in vivo with an antidote controlled platelet inhibitor.

Millions of individuals are prescribed platelet inhibitors, such as aspirin and clopidogrel, to reduce their risk of thrombosis-related clinical events. Unfortunately many platelet inhibitors are contraindicated in surgical settings because of their inherent bleeding risk complicating the treatment of patients who require surgery. We describe the development of a potent antiplatelet agent, an RNA aptamer-termed Ch-9.14-T10 that binds von Willebrand factor (VWF) with high affinity and inhibits thrombosis in a murine carotid artery damage model. As expected, when this potent antiplatelet agent is administered, it greatly increases bleeding from animals that are surgically challenged. To improve this antiplatelet agent's safety profile, we describe the generation of antidotes that can rapidly reverse the activity of Ch-9.14-T10 and limit blood loss from surgically challenged animals. Our work represents the first antidote controllable antiplatelet agent, which could conceivably lead to improved medical management of patients requiring antiplatelet medication who also need surgery.

Performance of the American Heart Association/American College of Cardiology/Heart Rhythm Society versus European Society of Cardiology guideline criteria for hospital admission of patients with syncope.

BACKGROUND: Current American College of Cardiology/American Heart Association/Heart Rhythm Society (ACC/AHA/HRS) and European Society of Cardiology (ESC) guidelines recommend different strategies to avoid low-yield admissions in patients with syncope. OBJECTIVE: The purpose of this study was to directly compare the safety and efficacy of applying admission criteria of both guidelines to patients presenting with syncope to the emergency department in 2 multicenter studies. METHODS: The international BASEL IX (BAsel Syncope EvaLuation) study (median age 71 years) and the U.S. SRS (Improving Syncope Risk Stratification in Older Adults) study (median age 72 years) were investigated. Primary endpoints were sensitivity/specificity for the adjudicated diagnosis of cardiac syncope (BASEL IX only) and 30-day major adverse cardiovascular events (30d-MACE). RESULTS: Among 2560 patients in the BASEL IX and 2085 in SRS studies, ACC/AHA/HRS and ESC criteria recommended admission for a comparable number of patients in BASEL IX (27% vs 28%), but ACC/AHA/HRS criteria less often in SRS (19% vs 32%; P <.01). Recommendations were discordant in ∼25% of patients. In BASEL IX, sensitivity for cardiac syncope and 30d-MACE among patients without admission criteria was comparable for ACC/AHA/HRS and ESC criteria (64% vs 65%, P = .86; and 67% vs 71%, P = .15, respectively). In SRS, sensitivity for 30d-MACE was lower with ACC/AHA/HRS (54%) vs ESC criteria (88%; P <.001). Similarly, specificity for cardiac syncope and 30d-MACE in BASEL IX was comparable for both guidelines, but in SRS the ACC/AHA/HRS guidelines showed a higher specificity for 30d-MACE than the ESC guidelines. CONCLUSION: ACC/AHA/HRS and ESC guidelines showed disagreement regarding admission for 1 in 4 patients and had only modest sensitivity, all indicating possible opportunities for improvements.

Development of an electrocardiogram-based risk calculator for a cardiac cause of syncope.

OBJECTIVE: To develop an ECG-based tool for rapid risk assessment of a cardiac cause of syncope in patients ≥40 years. METHODS: In a prospective international multicentre study, 2007 patients ≥40 years presenting with syncope were recruited in the emergency department (ED) of participating centres ranging from large university hospitals to smaller rural hospitals in eight countries from May 2010 to July 2017. 12-Lead ECG recordings were obtained at ED presentation following the syncopal event. The primary diagnostic outcome, a cardiac cause of syncope, was centrally adjudicated by two independent cardiologists using all available clinical information including 12-month follow-up. ECG predictors for a cardiac cause of syncope were identified using penalised backward selection and a continuous-scale likelihood was calculated based on regression analysis coefficients. Findings were validated in an independent US multicentre cohort including 2269 patients. RESULTS: In the derivation cohort, a cardiac cause of syncope was adjudicated in 267 patients (16%). Seven ECG criteria were identified as predictors for this outcome: heart rate and QTc-interval (continuous predictors), rhythm, atrioventricular block, ST-segment depression, bundle branch block and ventricular extrasystole/non-sustained ventricular tachycardia (categorical predictors). Diagnostic accuracy of these combined predictors for a cardiac cause of syncope was high (area under the curve 0.80, 95% CI 0.77 to 0.83). Overall, 138 patients (8%) were rapidly triaged towards rule-out and 181 patients (11%) towards rule-in of a cardiac cause of syncope. External validation showed similar performance. CONCLUSION: In patients ≥40 years with a syncopal event, a combination of seven ECG criteria enabled rapid assessment of the likelihood that syncope was due to a cardiac cause. TRIAL REGISTRATION NUMBER: NCT01548352 (BASEL IX), NCT01802398 (SRS study).

Early kinetics of cardiac troponin in suspected acute myocardial infarction.

INTRODUCTION AND OBJECTIVES: Release kinetics of high-sensitivity cardiac troponin (hs-cTn) T and I in patients with acute myocardial infarction (AMI) are incompletely understood. We aimed to assess whether hs-cTnT/I release in early AMI is near linear. METHODS: In a prospective diagnostic multicenter study the acute release of hs-cTnT and hs-cTnI within 1 and 2hours from presentation to the emergency department was quantified using 3 hs-cTnT/I assays in patients with suspected AMI. The primary endpoint was correlation between hs-cTn changes from presentation to 1 hour vs changes from presentation to 2hours, among all AMI patients and different prespecified subgroups. The final diagnosis was adjudicated by 2 independent cardiologists, based on serial hs-cTnT from the serial study blood samples and additional locally measured hs-cTn values. RESULTS: Among 2437 patients with complete hs-cTnT data, AMI was the adjudicated diagnosis in 376 patients (15%). For hs-cTnT, the correlation coefficient between 0- to 1-hour change and 0- to 2 hour change was 0.931 (95%CI, 0.916-0.944), P <.001. Similar findings were obtained with hs-cTnI (Architect) with correlation coefficients between 0- to 1-hour change and 0- to 2 hour change of 0.969 and hs-cTnI (Centaur) of 0.934 (P <.001 for both). Findings were consistent among type 1 and type 2 AMI and in the subgroup of patients presenting very early after chest pain onset. CONCLUSIONS: Patients presenting with early AMI showed a near linear release of hs-cTnT and hs-cTnI. This near linearity provides the pathophysiological basis for rapid diagnostic algorithms using 0- to 1-hour changes as surrogates for 0- to 2 hour or 0- to 3 hour changes. Registered at ClinicalTrials.gov (Identifier: NCT00470587).

Prevalence of Pulmonary Embolism in Patients With Syncope.

BACKGROUND: The prevalence of pulmonary embolism (PE) in patients presenting with syncope to the emergency department (ED) is largely unknown. This information, however, is necessary to balance the potential medical benefit or harm of systematic PE screening in patients presenting with syncope to the ED. OBJECTIVES: This study sought to determine the prevalence of PE in patients with syncope. METHODS: Unselected patients presenting with syncope to the ED were prospectively enrolled in a diagnostic multicenter study. Pre-test clinical probability for PE was assessed using the 2-level Wells score and the results of D-dimer testing using age-adapted cutoffs. Presence of PE was evaluated by imaging modalities, when ordered as part of the clinical assessment by the treating ED physician or by long-term follow-up data. RESULTS: Long-term follow-up was complete in 1,380 patients (99%) at 360 days and 1,156 patients (83%) at 720 days. Among 1,397 patients presenting with syncope to the ED, PE was detected at presentation in 19 patients (1.4%; 95% confidence interval [CI]: 0.87% to 2.11%). The incidence of new PEs or cardiovascular death during 2-year follow-up was 0.9% (95% CI: 0.5% to 1.5%). In the subgroup of patients hospitalized (47%), PE was detected at presentation in 15 patients (2.3%; 95% CI: 1.4% to 3.7%). The incidence of new PEs or cardiovascular death during 2-year follow-up was 0.9% (95% CI: 0.4% to 2.0%). CONCLUSIONS: PE seems to be a rather uncommon cause of syncope among patients presenting to the ED. Therefore, systematic PE-screening in all patients with syncope does not seem warranted. (BAsel Syncope EvaLuation Study [BASEL IX]; NCT01548352).

Outcome of Applying the ESC 0/1-hour Algorithm in Patients With Suspected Myocardial Infarction.

BACKGROUND: The European Society of Cardiology (ESC) recommends the 0/1-h algorithm for rapid triage of patients with suspected non-ST-segment elevation myocardial infarction (MI). However, its impact on patient management and safety when routinely applied is unknown. OBJECTIVES: This study sought to determine these important real-world outcome data. METHODS: In a prospective international study enrolling patients presenting with acute chest discomfort to the emergency department (ED), the authors assessed the real-world performance of the ESC 0/1-h algorithm using high-sensitivity cardiac troponin T embedded in routine clinical care and its associated 30-day rates of major adverse cardiac events (MACE) (the composite of cardiovascular death and MI). RESULTS: Among 2,296 patients, non-ST-segment elevation MI prevalence was 9.8%. In median, 1-h blood samples were collected 65 min after the 0-h blood draw. Overall, 94% of patients were managed without protocol violations, and 98% of patients triaged toward rule-out did not require additional cardiac investigations including high-sensitivity cardiac troponin T measurements at later time points or coronary computed tomography angiography in the ED. Median ED stay was 2 h and 30 min. The ESC 0/1-h algorithm triaged 62% of patients toward rule-out, and 71% of all patients underwent outpatient management. Proportion of patients with 30-day MACE were 0.2% (95% confidence interval: 03% to 0.5%) in the rule-out group and 0.1% (95% confidence interval: 0% to 0.2%) in outpatients. Very low MACE rates were confirmed in multiple subgroups, including early presenters. CONCLUSIONS: These real-world data document the excellent applicability, short time to ED discharge, and low rate of 30-day MACE associated with the routine clinical use of the ESC 0/1-h algorithm for the management of patients presenting with acute chest discomfort to the ED.

Rupture of an aneurysm of the noncoronary sinus of Valsalva into the right atrium.

A 32-year-old woman presented to the emergency department after the sudden onset of palpitations, dyspnoea and left-sided tinnitus. Echocardiography revealed a ruptured aneurysm of the noncoronary sinus of Valsalva into the right atrium. Due to deterioration of right heart failure with rapidly progressive decline of systemic blood pressure, the patient underwent immediate surgery with a patch repair of the ruptured aneurysm. A few days later, the patient was discharged home in good condition.

Combination of aptamer and drug for reversible anticoagulation in cardiopulmonary bypass.

Unfractionated heparin (UFH), the standard anticoagulant for cardiopulmonary bypass (CPB) surgery, carries a risk of post-operative bleeding and is potentially harmful in patients with heparin-induced thrombocytopenia-associated antibodies. To improve the activity of an alternative anticoagulant, the RNA aptamer 11F7t, we solved X-ray crystal structures of the aptamer bound to factor Xa (FXa). The finding that 11F7t did not bind the catalytic site suggested that it could complement small-molecule FXa inhibitors. We demonstrate that combinations of 11F7t and catalytic-site FXa inhibitors enhance anticoagulation in purified reaction mixtures and plasma. Aptamer-drug combinations prevented clot formation as effectively as UFH in human blood circulated in an extracorporeal oxygenator circuit that mimicked CPB, while avoiding side effects of UFH. An antidote could promptly neutralize the anticoagulant effects of both FXa inhibitors. Our results suggest that drugs and aptamers with shared targets can be combined to exert more specific and potent effects than either agent alone.

Prospective validation of prognostic and diagnostic syncope scores in the emergency department.

BACKGROUND: Various scores have been derived for the assessment of syncope patients in the emergency department (ED) but stay inconsistently validated. We aim to compare their performance to the one of a common, easy-to-use CHADS2 score. METHODS: We prospectively enrolled patients ≥ 40 years old presenting with syncope to the ED in a multicenter study. Early clinical judgment (ECJ) of the treating ED-physician regarding the probability of cardiac syncope was quantified. Two independent physicians adjudicated the final diagnosis after 1-year follow-up. Major cardiovascular events (MACE) and death were recorded during 2 years of follow-up. Nine scores were compared by their area under the receiver-operator characteristics curve (AUC) for death, MACE or the diagnosis of cardiac syncope. RESULTS: 1490 patients were available for score validation. The CHADS2-score presented a higher or equally high accuracy for death in the long- and short-term follow-up than other syncope-specific risk scores. This score also performed well for the prediction of MACE in the long- and short-term evaluation and stratified patients with accuracy comparative to OESIL, one of the best performing syncope-specific risk score. All scores performed poorly for diagnosing cardiac syncope when compared to the ECJ. CONCLUSIONS: The CHADS2-score performed comparably to more complicated syncope-specific risk scores in the prediction of death and MACE in ED syncope patients. While better tools incorporating biochemical and electrocardiographic markers are needed, this study suggests that the CHADS2-score is currently a good option to stratify risk in syncope patients in the ED. TRIAL REGISTRATION: NCT01548352.

Blockade of interleukin-13-mediated cell activation by a novel inhibitory antibody to human IL-13 receptor alpha1.

Interleukin-13 (IL-13) is a cytokine with a crucial role in the development of allergic asthma. The IL-13 receptor shares the IL-4Ralpha subunit with the IL-4R system, but contains as a specific component the IL-13Ralpha1 chain. Blocking signal release by IL-13 without affecting IL-4 function is a potentially interesting therapeutical option for the treatment of asthma. Employing genetic immunization, we generated a set of novel monoclonal antibodies to the IL-13Ralpha1 receptor that proved very specific and efficient inhibitors of human IL-13 activity. Receptor binding antibodies were identified by their specific reactivity with both human monocytes and a murine pro-B cell line overexpressing human IL-13Ralpha1 by flow cytometry and cell ELISA. A luciferase reporter cell system based on STAT6-mediated promoter activation in murine Ba/F3 cells was employed to screen the antibodies for IL-13 antagonistic properties. Inhibitory antibody effects were quantified by interference with IL-13-dependent proliferation of TF-1 cells. The capability of blocking IL-13-driven responses of primary, inflammation-relevant cells was tested by Western blot analysis of STAT6 tyrosine phosphorylation and expression of 15-lipoxygenase in monocytes from fresh blood. The most potent inhibitory antibody identified, GM1E7, inhibited IL-13-driven gene activation and cell proliferation in immune cell lines with IC(50) values in the low nanomolar range. Both short-term (STAT6 activation) and long-term (15-LO induction) responses of primary human blood cells to IL-13 were almost entirely blocked, whereas IL-4 effects remained virtually unaffected. GM1E7 is superior to available agents interfering with IL-13 activity in terms of specificity and efficiency and offers potential novel therapeutic perspectives for the treatment of allergic asthma.