Cardiac biomarkers for infarct diagnosis and early exclusion of acute coronary syndrome

The acute coronary syndrome (ACS) represents a diagnostic challenge: on the one hand patients need to be quickly identified to initiate treatment and on the other hand early exclusion of patients without ACS is important to relieve patient stress as well as overcrowded emergency departments. A growing number of biomarkers are becoming available to aid physicians with this task. This review gives an overview of the current research concerning early exclusion with an emphasis on the clinically most important biomarker: cardiac troponin

Tissue engineering of functional articular cartilage: the current status

Osteoarthritis is a degenerative joint disease characterized by pain and disability. It involves all ages and 70% of people aged >65 have some degree of osteoarthritis. Natural cartilage repair is limited because chondrocyte density and metabolism are low and cartilage has no blood supply. The results of joint-preserving treatment protocols such as debridement, mosaicplasty, perichondrium transplantation and autologous chondrocyte implantation vary largely and the average long-term result is unsatisfactory. One reason for limited clinical success is that most treatments require new cartilage to be formed at the site of a defect. However, the mechanical conditions at such sites are unfavorable for repair of the original damaged cartilage. Therefore, it is unlikely that healthy cartilage would form at these locations. The most promising method to circumvent this problem is to engineer mechanically stable cartilage ex vivo and to implant that into the damaged tissue area. This review outlines the issues related to the composition and functionality of tissue-engineered cartilage. In particular, the focus will be on the parameters cell source, signaling molecules, scaffolds and mechanical stimulation. In addition, the current status of tissue engineering of cartilage will be discussed, with the focus on extracellular matrix content, structure and its functionality

Circadian rhythm of cardiac troponin I and its clinical impact on the diagnostic accuracy for acute myocardial infarction

High-sensitivity cardiac troponin T (hs-cTnT) blood concentrations were shown to exhibit a diurnal rhythm, characterized by gradually decreasing concentrations throughout daytime, rising concentrations during nighttime and peak concentrations in the morning. We aimed to investigate whether this also applies to (h)s-cTnI assays and whether it would affect diagnostic accuracy for acute myocardial infarction (AMI).; Blood concentrations of cTnI were measured at presentation and after 1 h using four different cTnI assays: three commonly used sensitive (s-cTnI Architect, Ultra and Accu) and one experimental high-sensitivity assay (hs-cTnI Accu) in a prospective multicenter diagnostic study of patients presenting to the emergency department with suspected AMI. These concentrations and their diagnostic accuracy for AMI (quantified by the area under the curve (AUC)) were compared between morning (11 p.m. to 2 p.m.) and evening (2 p.m. to 11 p.m.) presenters.; Among 2601 patients, AMI was the final diagnosis in 17.6% of patients. Concentrations of (h)s-cTnI as measured using all four assays were comparable in patients presenting in the morning versus patients presenting in the evening. Diagnostic accuracy for AMI of all four (h)s-cTnI assays were high and comparable between patients presenting in the morning versus presenting in the evening (AUC at presentation: 0.90 vs 0.93 for s-cTnI Architect; 0.91 vs 0.94 for s-cTnI Ultra; 0.89 vs 0.94 for s-cTnI Accu; 0.91 vs 0.94 for hs-cTnI Accu).; Cardiac TnI does not seem to express a diurnal rhythm. Diagnostic accuracy for AMI is very high and does not differ with time of presentation.; NCT00470587, http://clinicaltrials.gov/show/NCT00470587

Droplet digital PCR of serum miR-499, miR-21 and miR-208a for the detection of functionally relevant coronary artery disease

Background: microRNAs (miRNAs) have shown promise as potential new biomarkers for myocardial injury and myocardial ischemia. New digital polymerase chain reaction (PCR) techniques allow for highly precise and reliable absolute direct quantification. Methods: In this pilot study we used droplet digital PCR (ddPCR) to assess if miRNAs might be released into circulation in patients with functionally relevant coronary artery disease (CAD). Blood samples for measurement of high-sensitivity cardiac troponin I (hs-cTnI) and miRNAs were obtained before, immediately after peak stress, and 2 h after stress testing in a blinded manner in consecutive patients referred for rest/stress myocardial perfusion single-photon emission tomography/computer tomography (MPI-SPECT/CT). ddPCR was used to directly quantify the serum concentrations of miR-21, miR-208a, and miR-499 as potential markers of myocardial injury/ischemia. Functionally relevant CAD was determined by expert interpretation of MPI-SPECT/CT, coronary angiography and fractional flow reserve, if performed. Results: Overall, 200 patients were included and functionally relevant CAD was detected in 85 of them (42%). NeithermiR-21, miR-208a, nor miR-499 concentrations differed at rest, stress, or 2-h after stress when comparing patients with versus without functionally relevant CAD, while hs-cTnI concentrations were significantly higher in patients with functionally relevant CAD (P < 0.001). Exercise-induced changes in miRNA or hs-cTnI concentrations did not have diagnostic utility and were similar in patients with versus without functionally relevant CAD. Conclusion: miR-208a, miR-21 and miR-499 concentrations at rest, after exercise and exercise-induced changes do not provide additional clinical value regarding the detection of functionally relevant CAD. (c) 2018 Elsevier B.V. All rights reserved

Accelerated diagnostic protocol using high-sensitivity cardiac troponin T in acute chest pain patients

Background: We aimed to evaluate the efficacy and safety of using high-sensitivity cardiac troponin T (hs-cTnT) within an accelerated diagnostic protocol (ADP) in patients presenting with symptoms suggestive of acute myocardial infarction (AMI) for rapid rule-out of AMI. Methods: In two independent large multicenter studies, levels of hs-cTnT at presentation and at 2 h were combined with the Thrombolysis In Myocardial Infarction (TIMI) risk score and ECG findings. The ADP defined patients with normal levels of hs-cTnT at presentation and 2 h, a TIMI score ≤ 1, and normal ECG findings as candidates for rapid rule-out of AMI and rapid discharge. Major adverse cardiac events (MACEs) occurring within 30-days were centrally adjudicated by two independent cardiologists. Results: In the derivation cohort, among 1085 consecutive patients 198 patients (18.2%) had a MACE. The ADP classified 374 patients (34.5%) as low-risk. None of these patients had a MACE at 30 days, resulting in a negative predictive value (NPV) of 100% (95% CI, 99.0–100%) and a sensitivity of 100% (95% CI, 98.2%–100%). In the validation cohort, among 1590 consecutive patients 231 patients (14.5%) had a MACE. The ADP classified 641 patients (40.3%) as low-risk. 6 of these patients had a MACE at 30 days, resulting in a NPV of 99.1% (95% CI, 98.0–99.6%) and a sensitivity of 97.4% (95% CI, 94.5–98.8%). Conclusions: The ADP including hs-cTnT allows early identification 35 to 40% of patients to be at extremely low risk of MACE and therefore ideal candidates for outpatient management

ESAIC focused guideline for the use of cardiac biomarkers in perioperative risk evaluation.

BACKGROUND: In recent years, there has been increasing focus on the use of cardiac biomarkers in patients undergoing noncardiac surgery. AIMS: The aim of this focused guideline was to provide updated guidance regarding the pre-, post- and combined pre-and postoperative use of cardiac troponin and B-type natriuretic peptides in adult patients undergoing noncardiac surgery. METHODS: The guidelines were prepared using Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology. This included the definition of critical outcomes, a systematic literature search, appraisal of certainty of evidence, evaluation of biomarker measurement in terms of the balance of desirable and undesirable effects including clinical outcomes, resource use, health inequality, stakeholder acceptance, and implementation. The panel differentiated between three different scopes of applications: cardiac biomarkers as prognostic factors, as tools for risk prediction, and for biomarker-enhanced management strategies. RESULTS: In a modified Delphi process, the task force defined 12 critical outcomes. The systematic literature search resulted in over 25,000 hits, of which 115 full-text articles formed the body of evidence for recommendations. The evidence appraisal indicated heterogeneity in the certainty of evidence across critical outcomes. Further, there was relevant gradient in the certainty of evidence across the three scopes of application. Recommendations were issued and if this was not possible due to limited evidence, clinical practice statements were produced. CONCLUSION: The ESAIC focused guidelines provide guidance on the perioperative use of cardiac troponin and B-type natriuretic peptides in patients undergoing noncardiac surgery, for three different scopes of application