P1756The protein APRIL predicts adverse outcomes in DAPT patients better than NT-proBNP and troponin

Aim

Dual antiplatelet therapy (DAPT) is a mainstay of post-ACS treatment. However, prediction of adverse events in these patients needs improving. We show here that the TNFα-related protein APRIL (which is produced in platelets and atherosclerotic plaque) is a superior predictor of MACE and new MI in DAPT recipients post-ACS.

Methods

We prospectively recruited 518 patients presenting with the primary complaint of acute chest pain to our hospital ED. Patients were adjudicated to have ACS by 2 independent cardiologists in accordance with ESC guidelines with hsTnI as biomarker. Plasma EDTA samples taken at presentation and 2 hours after were interrogated for APRIL measurements using a two site ELISA. Clinical data/variables, standard biochemistry analytes, hsTnT and NT-proBNP were also measured. Statistical assessments were made using SPSS v23 (IBM). Data for all biomarkers were treated as continuous variables and are presented as median (interquartile range, (IQR)). Statistical assessment of the comparative diagnostic abilities of APRIL, hsTnT, NT-proBNP and hsTnI were assessed using receiver operator curve (ROC) area under the curve (AUC) analysis. The comparative power of each biomarker (log values) to predict new MACE, MI, bleeding and mortality in 1) the whole group and in 2) DAPT recipients alone, within 2 yrs of index presentation was undertaken using a logistic regression base model (95% CI) that included all clinical variables and hsTnI and hsTnT, with APRIL and NT-proBNP each included in additional multivariate analyses.

Results

Of the 518 recruited patients (median age 63 (IQR: 54–73, 35% female), 152 were adjudicated to have ACS (29%, 115 MI, 37 UAP). Presentation APRIL levels were higher in those with a cardiac versus non-cardiac cause for presentation (3.0, (2.0–4.7) vs. 2.4, (1.6–3.8) ng/mL, P=0.001) and positively correlated with hsTnT and NT-proBNP (all P<0.001), but it did not add to the hsTnI (ROC = 0.96) or hsTnT (ROC =0.92) assisted diagnosis of ACS. In all 518 patients, in the multivariate regression model, APRIL was a significant independent predictor of mortality (n=54, P=0.032), new MI (n=43, P=0.006), new ADHF (n=24, P=0.016) and MACE (n=71, P=0.005) that was additive to NT-proBNP and troponin. In DAPT recipients alone (n=156), APRIL was the only biomarker to independently predict new MI (n=27, 95% CI: 1.125–3.982, P=0.020) and MACE (n=37, 95% CI: 1.058–3.389, P=0.031). None of the markers, only age, predicted bleeding episodes.

Conclusion

APRIL is an platelet/plaque derived marker that provides independent risk assessment in ACS patients. In DAPT recipients, the ability of APRIL to predict new MI and MACE is superior to that of cardiac troponins and NT-proBNP and could be used to identify high risk individuals.

Acknowledgement/Funding

Health Research Council of New Zealand; Heart Foundation of New Zealand

P2674Rapid rule-out of myocardial infarction with a novel high precision point-of-care troponin assay appears safe and effective

Background

High sensitivity troponin assays were developed to improve analytical sensitivity and precision at the decision cut-points for the diagnosis and rule out of acute myocardial infarction (AMI). Central laboratory assays have achieved this but point of care assays, which have the ability to accelerate decision making due to much shorter turnaround times, have remained lacking.

Purpose

To ascertain the threshold for decision making and subsequent clinical utility for ruling out AMI on presentation in patients attending the emergency department acutely with chest pain, using a high precision point of care troponin assay (TnI Nx), (i-STAT, Abbott).

Methods

We measured arrival TnI-Nx concentrations in stored plasma samples in adults presenting acutely to the emergency department with chest pain. The primary outcome was an AMI or cardiac death on index admission or within 30 days. We used 2000 bootstrapped data sets to derive and validate a suitable threshold for TnI-Nx before calculating diagnostic test performance. We pre-specified this threshold must have a <1% false negative rate for the primary outcome. We compared this with a core laboratory high sensitivity troponin I (hs-TnI) (Abbott Architect) using the early rule-out cut-point (European Society of Cardiology) at the limit of detection (2 ng/L).

Results

We recruited 1320 patients of whom 192 (14.1%) had the primary outcome. The TnI-Nx threshold was determined to be 8 ng/L with subsequent sensitivity of 99.0% (95% confidence interval: 97.3% to 100%), negative predictive value of 99.7% (99.2% to 100%) and specificity of 59.0% (56.0% to 62.0%). The hs-TnI had a sensitivity of 99.5% (98.2% to 100%), negative predictive value of 99.7% (99.0% to 100%), and specificity of 28.4% (25.8% to 31.2%) at 2ng/L.

Conclusion

A high precision point of care assay, TnI-Nx, with a decision threshold of 8ng/L, has comparable rule out performance compared with a core laboratory high sensitivity assay and therefore could potentially be used for early decision making in the assessment of acute chest pain.

Acknowledgement/Funding

Research grant from Abbott Point of Care. Senior Research Fellowship from ECF, CMRF and CDHB. Clinical Research Fellowship from NZ HRC

P3408The signal peptide of CNP is a novel predictor of MI, MACE and bleeding risk in chest pain patients

Aim

CNP is an important vascular and cardiac derived member of the natriuretic peptide family. We have previously provided the first reports that the signal peptide of CNP (CNPsp) is present in the human circulation and is elevated in those with chest pain suspicious of ACS. Here, show that CNPsp levels are highly predictive of new MI, MACE and post-index bleeding in patients presenting with potential ACS.

Methods

We prospectively recruited 493 patients presenting with the primary complaint of acute chest pain to our hospital ED. Patients were adjudicated as ACS by 2 independent cardiologists in accordance with ESC guidelines with hsTnI as biomarker. Plasma EDTA samples taken at presentation and 2 hours after were interrogated for CNPsp measurements using our validated, specific assay. Clinical data/variables, standard biochemistry analytes, hsTnT and NT-proBNP (both Roche Cobas e411) were also measured. Statistical assessments were made using SPSS v23. Data for all biomarkers were treated as continuous variables and are presented as median (interquartile range, (IQR)). Statistical assessment of the comparative abilities of CNPsp, hsTnT, NT-proBNP and hsTnI (log values) to predict new MACE, MI, bleeding and mortality within 2 yrs of index presentation was undertaken using a logistic regression base model (95% CI) that included all clinical variables and hsTnI and hsTnT and NT-proBNP, with CNPsp added to into the multivariate analyses.

Results

Of the 493 recruited patients (median age 63 (IQR: 54–73, 35% female), 148 were adjudicated to have ACS (30%, 109 MI, 39 UAP). Presentation CNPsp levels were not higher in those with adjudicated ACS versus non-ACS (51, (45–65) vs. 50, (42–63) pmol/L, P=0.412), did not correlate with hsTnI, hsTnT or NT-proBNP, but were significantly lower in those with a history of MI (49, (42–59) vs. 51, (43–64) pmol/L, P=0.044). In contrast, they were significantly higher in those with ECG ST-depression (56, (47–85) vs. 50 (42–62) pmol/L, P=0.038). In the multivariate regression model of all 493 patients, lower values of CNPsp were a significant multivariate predictor of new MI (n=37, 95% CI: 0.06–0.89, P=0.038), MACE (n=64, 95% CI: 0.08–0.81, P=0.020) and new bleeding (n=40, 95% CI: 0.05–0.63, P=0.005) within 2 years of presentation. This predictive ability was additive and independent from NT-proBNP and troponin.

Conclusion

This is the first report that CNPsp measurement provides meaningful and independent risk assessment of important outcomes in ACS patients. In particular, the fact that lower levels of CNPsp are predictive of negative MI, MACE and bleeding outcomes suggests that CNPsp may have an unappreciated protective role in the cardiovascular system.

Acknowledgement/Funding

Health Research Council of New Zealand; Heart Foundation of New Zealand

Validation of NICE diagnostic guidance for rule out of myocardial infarction using high-sensitivity troponin tests

OBJECTIVE

To validate the National Institute for Health and Care Excellence (NICE) recommended algorithms for high-sensitivity troponin (hsTn) assays in adults presenting with chest pain.

METHODS

International post hoc analysis of three prospective, observational studies from tertiary hospital emergency departments. The primary endpoint was cardiac death or acute myocardial infarction (AMI) within 24 hours of presentation, and the secondary endpoint was major adverse cardiac events (MACE) at 30 days.

RESULTS

15% of patients were diagnosed with non-ST elevation myocardial infarction (MI) on admission. The hsTnI algorithm classified 2506/3128 (80.1%) of patients as 'ruled out' with 50 (2.0%) missed MI. 943/3128 (30.1%) of patients had a troponin I level below the limit of detection on admission with 2 (0.2%) missed MI. For the hsTnT algorithm, 1794/3374 (53.1%) of patients were 'ruled out' with 7 (0.4%) missed MI. 490/3374 (14.5%) of patients had a troponin T below the limit of blank on admission with no MI. MACE at 30 days occurred in 10.7% and 8.5% of patients 'ruled out' defined by the hsTnI and hsTnT algorithms, respectively.

CONCLUSIONS

The NICE algorithms could identify patients with low probability of AMI within 2 hours; however, neither strategy performed as predicted by the NICE diagnostic guidance model. Additionally, the rate of MACE at 30 days was sufficiently high that the algorithms should only be used as one component of a more extensive model of risk stratification.

TRIAL REGISTRATION NUMBER

ACTRN12611001069943, NCT00470587; post-results.

Soft tissue injuries: 7 Shoulder and elbow

A description of soft tissue injuries to the shoulder and elbow, together with assessment, imaging and treatment considerations.

Synthesis and antitumor activity of 4-aminomethylthioxanthenone and 5-aminomethylbenzothiopyranoindazole derivatives

Two new series of antitumor agents, 4-aminomethylthioxanthenones (6-50) and 5-aminomethylbenzothiopyranoindazoles (51-61), are described and compared. Nearly all members of both series display excellent in vivo activity versus murine pancreatic adenocarcinoma 03 (Panc03) although there is little to distinguish the two series from each other. In both series there is no discernible relationship between structure and in vivo efficacy. Selected analogues were evaluated in vitro; all were observed to have moderate to strong DNA binding via intercalation. However, varying degrees of in vitro P388 cytotoxicity and topoisomerase II inhibition were seen. In general, those molecules which exhibited strong topoisomerase II inhibition were significantly more cytotoxic than those which did not. In both series, those derivatives (48-50, 60, and 61) having a phenolic hydroxy substitution exhibited the most potent P388 cytotoxicity and topoisomerase II inhibition.

Oxadiazoles as ester bioisosteric replacements in compounds related to disoxaril. Antirhinovirus activity

A series of 1,2,4-oxadiazoles has been prepared as ester bioisosteres and tested against 15 human rhinovirus serotypes, and the MIC80, the concentration which inhibits 80% or 12 of the serotypes tested, was determined. Homologation of the alkyl group attached to the oxadiazole ring resulted in a reduction in activity with increased chain length. Introduction of hydrophilic groups in this position rendered the compounds inactive. Increasing the length of the side chain attached to the isoxazole ring resulted in an increase in activity. Replacement of the methyl with alkoxyalkyl substituents retained activity; however, introduction of a hydroxyl group on to the side chain reduced activity. Compound 8a, where both the isoxazole and oxadiazole rings were substituted with methyl groups, was one of the most active compounds in the series. A comparison was made between 8a and the two isomeric oxadiazoles 41 and 46, and an attempt was made to explain the difference in activity by examining electrostatic potential maps and by an energy profiling study. No conclusive results were obtained from these studies.

Stability of miconazole in peritoneal dialysis fluid

The stability of miconazole when mixed with peritoneal dialysis (PD) fluid and stored in plastic bags or glass ampuls was determined. Admixtures of miconazole and PD fluid were prepared in 2-L polyvinyl chloride (PVC) bags and in 1-mL glass ampuls to give a nominal initial concentration of 20 mg/mL. Duplicate samples of each solution were assayed in duplicate by high-performance liquid chromatography immediately after preparation and at various intervals up to nine days. All admixtures were stored in ambient light at 20 +/- 2 degrees C. A substantial loss of miconazole (greater than 10% of the initial concentration) occurred within four hours for admixtures stored in PVC bags, whereas similar solutions retained more than 90% of their initial miconazole concentration for at least three days when stored in glass ampuls under the same conditions. This suggests that the observed loss of miconazole from the PVC bags was largely due to an interaction with the container, rather than to chemical degradation in solution. About 28% of the miconazole lost from the solution during storage in PVC bags was recovered from the plastic by methanolic extraction. The rapid loss of miconazole when the drug was mixed with PD fluid and stored in PVC bags indicates that such admixtures should be prepared immediately before administration.

Distribution and metabolism of 1,2,4-trimethylbenzene (pseudocumene) in the rat

1. Single doses of 1,2,4-trimethylbenzene (124TMB) or 14C-124TMB were administered orally to rats for metabolism and distribution studies. 2. 14C-124TMB was rapidly and widely distributed throughout the body with the highest levels in adipose tissue. No other preferential uptake of 14C-124TMB by any of the organs or tissues examined was evident. 3. Tissue levels declined rapidly within 24 h after dosage, with more than 99% of the administered radioactivity recovered in the urine during this period. 4. A complex mixture of isomeric trimethylphenols, dimethylbenzyl alcohols, dimethylbenzoic acids and dimethylhippuric acids excreted in the urine accounted for more than 81% of the administered dose. The major metabolites were 3,4-dimethylhippuric acid (30.2% dose), 2,4-dimethylbenzyl alcohol (12.7% dose, primarily as sulphate and glucuronide conjugates) and 2,5-dimethylbenzyl alcohol (11.7% dose, primarily as sulphate and glucuronide conjugates).

Plasma protein binding of phenytoin in 100 epileptic patients

The plasma protein binding of phenytoin was investigated in 100 epileptic patients, using equilibrium dialysis at 37 degrees C. The unbound fractions of phenytoin in plasma formed a skewed distribution, with a range of 9.7 to 24.7% and a median value of 12.3%. Most (80%) patients appeared to form one group with free phenytoin fractions from 9.7 to 14.5%, while the remainder formed a group with elevated free fractions (greater than 14.5%). Total and unbound plasma concentrations of phenytoin were strongly correlated (r=0.95, P less than 0.0001). There was a weak correlation between increasing age and the unbound phenytoin fraction (r=0.28, P less than 0.01). The results indicate that measurement of the total phenytoin concentration in plasma should usually provide a reliable index of anticonvulsant effect. However, determination of the unbound phenytoin fraction would be beneficial in the management of those patients in whom this fraction may be elevated, due to interacting drugs or biochemical abnormalities.

Absorption and metabolism of lanatoside C. II. Fate after oral administration

The absorption, metabolism, and excretion of lanatoside C were studied in hospitalized subjects following oral administration of the tritiated drug. Previous reports of an unusual double peak in plasma levels of radioactivity were confirmed. Fifty plasma samples taken from 31 patients showed that an average of 74% of the radioactive material was digoxin and its metabolites. There was little or no lanatoside C in 36 of the 50 samples of plasma. Similar results were obtained for urine radioactivity. The results confirm that lanatoside C is converted to "digoxin" in the gut prior to absorption as previously proposed by us. "Digoxin" refers to digoxin and its breakdown products, namely, digoxigenin and its mono- and didigitoxosides. According to these proposals, the conversion to "digoxin" takes place partly as a result of acid hydrolysis in the gut and partly by the action of bacteria in the intestine. The effects of concurrent administration of antacid therapy, anticholinergic therapy, and food on the fate of oral lanatoside C were separately studied. There were no significant differences between groups with respect to the amount of radioactive material absorbed or excreted, but there were marked qualitative differences in the plasma profiles. There was a statistically significant increase in the time to the first peak in plasma radioactivity in patients concurrently receiving either food or anticholinergic therapy and there was a significant decrease in the relative height of the first peak in patients treated concurrently with antacid.