Abstract Spontaneously beating engineered heart tissue (EHT) represents an advanced in vitro model for drug testing and disease modeling, but cardiomyocytes in EHTs are less mature and generate lower ...forces than in the adult heart. We devised a novel pacing system integrated in a setup for videooptical recording of EHT contractile function over time and investigated whether sustained electrical field stimulation improved EHT properties. EHTs were generated from neonatal rat heart cells (rEHT, n = 96) or human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hEHT, n = 19). Pacing with biphasic pulses was initiated on day 4 of culture. REHT continuously paced for 16–18 days at 0.5 Hz developed 2.2 × higher forces than nonstimulated rEHT. This was reflected by higher cardiomyocyte density in the center of EHTs, increased connexin-43 abundance as investigated by two-photon microscopy and remarkably improved sarcomere ultrastructure including regular M-bands. Further signs of tissue maturation include a rightward shift (to more physiological values) of the Ca 2 + -response curve, increased force response to isoprenaline and decreased spontaneous beating activity. Human EHTs stimulated at 2 Hz in the first week and 1.5 Hz thereafter developed 1.5 × higher forces than nonstimulated hEHT on day 14, an ameliorated muscular network of longitudinally oriented cardiomyocytes and a higher cytoplasm-to-nucleus ratio. Taken together, continuous pacing improved structural and functional properties of rEHTs and hEHTs to an unprecedented level. Electrical stimulation appears to be an important step toward the generation of fully mature EHT.
The safety of the European Society of Cardiology (ESC) 0/1-h algorithm for rapid rule-out and rule-in of non–ST-segment elevation myocardial infarction (NSTEMI) using high-sensitivity cardiac ...troponin (hs-cTn) has been questioned.
This study aimed to validate the diagnostic performance of the 0/1-h algorithm in a large multicenter study.
The authors prospectively enrolled unselected patients in 6 countries presenting to the emergency department with symptoms suggestive of NSTEMI. Final diagnosis was centrally adjudicated by 2 independent cardiologists. Hs-cTnT and hs-cTnI blood concentrations were measured at presentation and after 1 h. Safety of rule-out was quantified by the negative predictive value (NPV) for NSTEMI, accuracy of rule-in by the positive predictive value (PPV), and overall efficacy by the proportion of patients triaged towards rule-out or rule-in within 1 h.
Prevalence of NSTEMI was 17%. Among 4,368 patients with serial hs-cTnT measurements available, safety of rule-out (NPV 99.8%, 2,488 of 2,493), accuracy of rule-in (PPV 74.5%, 572 of 768), and overall efficacy were high by assigning three-fourths of patients either to rule-out (57%, 2,493 to 4,368) or rule-in (18%, 768 to 4,368). Similarly, among 3,500 patients with serial hs-cTnI measurements, safety of rule-out (NPV 99.7%, 1,528 of 1,533), accuracy of rule-in (PPV 62.3%, 498 of 800), and overall efficacy were high by assigning more than two-thirds of patients either to rule-out (44%, 1,533 of 3,500) or rule-in (23%, 800 of 3,500). Excellent safety was confirmed in multiple subgroup analyses including patients presenting early (≤3 h) after chest pain onset.
The ESC 0/1-h algorithm using hs-cTnT and hs-cTnI is very safe and effective in triaging patients with suspected NSTEMI. (Advantageous Predictors of Acute Coronary Syndromes Evaluation APACE; NCT00470587; and Biomarkers in Acute Cardiac Care BACC; NCT02355457)
Display omitted
High-sensitivity cardiac troponin (hs-cTn) assays provide higher diagnostic accuracy for acute myocardial infarction (AMI) when compared with conventional assays, but may result in increased use of ...unnecessary coronary angiographies due to their increased detection of cardiomyocyte injury in conditions other than AMI.
We evaluated the impact of the clinical introduction of high-sensitivity cardiac troponin T (hs-cTnT) on the use of coronary angiography, stress testing, and time to discharge in 2544 patients presenting with symptoms suggestive of AMI to the emergency department (ED) within a multicentre study either before (1455 patients) or after (1089 patients) hs-cTnT introduction. Acute myocardial infarction was more often the clinical discharge diagnosis after hs-cTnT introduction (10 vs. 14%, P < 0.001), while unstable angina less often the clinical discharge diagnosis (14 vs. 9%, P = 0.007). The rate of coronary angiography was similar before and after the introduction of hs-cTnT (23 vs. 23%, P = 0.092), as was the percentage of coronary angiographies showing no stenosis (11 vs. 7%, P = 0.361). In contrast, the use of stress testing was substantially reduced from 29 to 19% (P < 0.001). In outpatients, median time to discharge from the ED decreased by 79 min (P < 0.001). Mean total costs decreased by 20% in outpatients after the introduction of hs-cTnT (P = 0.002).
The clinical introduction of hs-cTn does not lead to an increased or inappropriate use of coronary angiography. Introduction of hs-cTn is associated with an improved rule-out process and thereby reduces the need for stress testing and time to discharge.
www.clinicaltrials.gov. Identifier, NCT00470587.
High-sensitivity cardiac troponin assays enable myocardial infarction to be ruled out earlier, but the optimal approach is uncertain. We compared the European Society of Cardiology rule-out pathway ...with a pathway that incorporates lower cardiac troponin concentrations to risk stratify patients.
Patients with suspected acute coronary syndrome (n=1218) underwent high-sensitivity cardiac troponin I measurement at presentation and 3 and 6 or 12 hours. We compared the European Society of Cardiology pathway (<99th centile at presentation or at 3 hours if symptoms <6 hours) with a pathway developed in the High-STEACS study (High-Sensitivity Troponin in the Evaluation of Patients With Acute Coronary
yndrome) population (<5 ng/L at presentation or change <3 ng/L and <99th centile at 3 hours). The primary outcome was a comparison of the negative predictive value of both pathways for index type 1 myocardial infarction or type 1 myocardial infarction or cardiac death at 30 days. We evaluated the primary outcome in prespecified subgroups stratified by age, sex, time of symptom onset, and known ischemic heart disease.
The primary outcome occurred in 15.7% (191 of 1218) patients. In those less than the 99th centile at presentation, the European Society of Cardiology pathway ruled out myocardial infarction in 28.1% (342 of 1218) and 78.9% (961 of 1218) at presentation and 3 hours, respectively, missing 18 index and two 30-day events (negative predictive value, 97.9%; 95% confidence interval, 96.9-98.7). The High-STEACS pathway ruled out 40.7% (496 of 1218) and 74.2% (904 of 1218) at presentation and 3 hours, missing 2 index and two 30-day events (negative predictive value, 99.5%; 95% confidence interval, 99.0-99.9;
<0.001 for comparison). The negative predictive value of the High-STEACS pathway was greater than the European Society of Cardiology pathway overall (
<0.001) and in all subgroups, including those presenting early or known to have ischemic heart disease.
Use of the High-STEACS pathway incorporating low high-sensitivity cardiac troponin concentrations rules out myocardial infarction in more patients at presentation and misses 5-fold fewer index myocardial infarctions than guideline-approved pathways based exclusively on the 99th centile.
URL: http://clinicaltrials.gov. Unique identifier: NCT01852123.
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.
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.
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
=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 (
<0.01 for LOD versus each of the other strategies).
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.
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00470587.
Uncertainties regarding the most appropriate definition and treatment of type 2 myocardial infarction (T2MI) due to supply-demand mismatch have contributed to inconsistent adoption in clinical ...practice.
This study sought a better understanding of the effect of the definition of T2MI on its incidence, treatment, and event-related mortality, thereby addressing an important unmet clinical need.
The final diagnosis was adjudicated in patients presenting with symptoms suggestive of myocardial infarction by 2 independent cardiologists by 2 methods: 1 method required the presence of coronary artery disease, a common interpretation of the 2007 universal definition (T2MI2007); and 1 method did not require coronary artery disease, the 2012 universal definition (T2MI2012).
Overall, 4,015 consecutive patients were adjudicated. The incidence of T2MI based on the T2MI2007 definition was 2.8% (n = 112). The application of the more liberal T2MI2012 definition resulted in an increase of T2MI incidence of 6% (n = 240), a relative increase of 114% (128 reclassified patients, defined as T2MI2012reclassified). Among T2MI2007, 6.3% of patients received coronary revascularization, 22% dual-antiplatelet therapy, and 71% high-dose statin therapy versus 0.8%, 1.6%, and 31% among T2MI2012reclassified patients, respectively (all p < 0.01). Cardiovascular mortality at 90 days was 0% among T2MI2012reclassified, which was similar to patients with noncardiac causes of chest discomfort (0.2%), and lower than T2MI2007 (3.6%) and type 1 myocardial infarction (T1MI) (4.8%) (T2MI2012reclassified vs. T2MI2007 and T1MI: p = 0.03 and 0.01, respectively).
T2MI2012reclassified has a substantially lower event-related mortality rate compared with T2MI2007 and T1MI. (Advantageous Predictors of Acute Coronary Syndromes Evaluation APACE Study; NCT00470587)
Display omitted
The early triage of patients toward rule-out and rule-in of acute myocardial infarction (AMI) is challenging. Therefore, we aimed to develop a 2-h algorithm that uses high-sensitivity cardiac ...troponin I (hs-cTnI).
We prospectively enrolled 1435 (derivation cohort) and 1194 (external validation cohort) patients presenting with suspected AMI to the emergency department. The final diagnosis was adjudicated by 2 independent cardiologists. hs-cTnI was measured at presentation and after 2 h in a blinded fashion. We derived and validated a diagnostic algorithm incorporating hs-cTnI values at presentation and absolute changes within the first 2 h.
AMI was the final diagnosis in 17% of patients in the derivation and 13% in the validation cohort. The 2-h algorithm developed in the derivation cohort classified 56% of patients as rule-out, 17% as rule-in, and 27% as observation. Resulting diagnostic sensitivity and negative predictive value (NPV) were 99.2% and 99.8% for rule-out; specificity and positive predictive value (PPV) were 95.2% and 75.8% for rule-in. Applying the 2-h algorithm in the external validation cohort, 60% of patients were classified as rule-out, 13% as rule-in, and 27% as observation. Diagnostic sensitivity and NPV were 98.7% and 99.7% for rule-out; specificity and PPV were 97.4% and 82.2% for rule-in. Thirty-day survival was 100% for rule-out patients in both cohorts.
A simple algorithm incorporating hs-cTnI baseline values and absolute 2-h changes allowed a triage toward safe rule-out or accurate rule-in of AMI in the majority of patients.
Abstract Objective The novel high-sensitivity cardiac troponin (hs-cTn) 0 h/1 h-algorithm substantially improves the early triage of patient's assigned “rule-out” or “rule-in” of acute myocardial ...infarction (AMI), while diagnostic uncertainty remains in that 25–30% of patients assigned to “observe”. We aimed to better characterize these patients. Methods In a prospective multicenter diagnostic study, we applied the hs-cTnT 0 h/1 h-algorithm in 2213 unselected patients presenting with symptoms suggestive of AMI to the emergency department. The final diagnosis was adjudicated by two independent cardiologists using all available information. Survival at 720-days was the prognostic endpoint. Findings were validated using a hs-cTnI 0 h/1 h-algorithm. Results Twenty-four percent (n = 523) of patients were assigned to “observe” by the hs-cTnT 0 h/1 h-algorithm. These patients differed significantly in multiple characteristics from “rule-out” and “rule-in” patients: they were older, in 75% male, and very often (57%) had pre-existing coronary artery disease (CAD). Diagnostic uncertainty for the presence of an AMI/UA was high. Only 39% of patients were suitable for coronary computed tomography angiography (CCTA). The most common final adjudicated diagnoses were non-cardiac disease (38%), non-coronary cardiac disease (24%), unstable angina (UA, 21%), and AMI (15%). Absolute hs-cTnT-changes within 3 h had the highest diagnostic accuracy for AMI (AUC 0.86). Cumulative 720-day survival rate was 86%, which was significantly lower as compared to “rule-out” (p < 0.001) and comparable to “rule-in” (p = ns). Findings were similar for the hs-cTnI “observe” zone. Conclusion “Observe” patients are typically elderly men with pre-existing CAD and high long-term mortality. Absolute hs-cTn-changes within 3 h, functional stress imaging and coronary angiography are the key diagnostic modalities.
PDF
