First-passage time of a Brownian searcher with stochastic resetting to random positions

We study the effect of a resetting point randomly distributed around the origin on the mean first-passage time of a Brownian searcher moving in one dimension. We compare the search efficiency with that corresponding to reset to the origin and find that the mean first-passage time of the latter can be larger or smaller than the distributed case, depending on whether the resetting points are symmetrically or asymmetrically distributed. In particular, we prove the existence of an optimal reset rate that minimizes the mean first-passage time for distributed resetting to a finite interval if the target is located outside this interval. When the target position belongs to the resetting interval or it is infinite then no optimal reset rate exists, but there is an optimal resetting interval width or resetting characteristic scale which minimizes the mean first-passage time. We also show that the first-passage density averaged over the resetting points depends on its first moment only. As a consequence, there is an equivalent point such that the first-passage problem with resetting to that point is statistically equivalent to the case of distributed resetting. We end our study by analyzing the fluctuations of the first-passage times for these cases. All our analytical results are verified through numerical simulations.

Implications of starting antiepileptic treatment prior to electroencephalography in first epileptic seizures

INTRODUCTION

This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure.

METHODS

We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72 hours after the seizure, and the factors related with seizure recurrence.

RESULTS

We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P = .25) or with the risk of recurrence within 6 months (P = .63).

CONCLUSIONS

Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

Acute coronary syndromes in the elderly: prognostic impact of anaemia

Introduction

The increase in life expectancy is a reality and cardiovascular disease incidence rises with it. The elderly are fragile patients with high prevalence of multiple comorbidities. Anaemia is one of them and, in most cases, has multifactorial causes. After an acute coronary syndrome (ACS), the thrombotic versus haemorrhagic risks in these patients are hard to balance.

Aim

The aim of this study is to evaluate prognostic impact of anaemia in the elderly after an ACS.

Methods

Retrospective analysis of consecutive patients admitted to a single Intensive Coronary Unit between 2009 and 2016 with the diagnosis of ACS. Patients younger than 80 years old were excluded. A complete blood count was collected upon admission and anaemia was defined for haemoglobin values below 12.5mg/dL. Cox regression analysis and Kaplan-Meyer curves were conducted to determine prognostic value of anaemia in this specific population. Multivariate analysis with other comorbidities and antithrombotic therapy was also performed.

Results

A total of 353 patients (median age of 84.0±6.0 years old; 52.1% males; 51.3% with anaemia) were enrolled. In cox regression analysis, anaemia predicted mortality (HR 1.614; 95% CI 1.199–2.172; P=0.002). In multivariate analysis – including gender, presence of hypertension, diabetes, chronic kidney disease and atrial fibrillation (AF) at admission, anaemia proved to be an independent predictor of mortality (HR 1.521, 95% CI 1.119–2.069, P=0.007). Adding all previous and discharge antithrombotic therapy – antiplatelet inhibition and oral anticoagulants – to the equation, anaemia maintained its prognostic value (HR 2.157; 95% CI 1.130–4.116; P=0.020). Both AF and being discharged from the hospital with ticagrelor also increased mortality risk in these patients (HR 2.188, 95% CI 1.177–4.070, P=0.13 for AF; HR 1.906, 05% CI 1.011–3.594, P=0.046 for ticagrelor at discharge).

Conclusions

After an ACS, anaemia proved to be an independent predictor of mortality in the elderly. This emphasizes the importance of its adequate aetiology investigation and treatment and careful selection of antithrombotic therapy following an ACS.

Funding Acknowledgement

Type of funding sources: None.

Inflammation in acute coronary syndrome: prognostic significance

Funding Acknowledgements

Type of funding sources: None.

Background

In patients with acute coronary syndrome (ACS) the acute phase reactant, C-reactive protein (CRP), might be significantly elevated. Several reports suggest that CRP may play a direct pathophysiological role on the development and progression of atherosclerosis, and CRP values correlate with infarct size when measured by magnetic resonance imaging.

Purpose

The aim of the present study was to evaluate the prognostic value of CRP in patients presenting with an ACS.

Methods

Retrospective analysis of 635 consecutively admitted patients due to ACS in a single coronary intensive care unit. CRP levels were measured at admission. Clinical variables and therapeutic strategies were examined. The primary endpoint analysed during follow-up was all-cause mortality. Possible predictors for all-cause mortality were assessed by Cox regression models. When statistically significant values were found in univariate analysis, multivariate analysis was used to determine whether CRP was an independent predictor of outcome.

Results

In the studied sample, 75% were male. Median age was 69 [interquartile range (IQR) 57–78]. ST-elevation myocardial infarction (STEMI) occurred in 39.6%, non-ST segment elevation myocardial infarction in 44.9% and unstable angina in 15.5% of the patients. Median left ventricular ejection fraction (LVEF) was 48% (IQR 40–55%) and median CRP level at admission 0.7 mg/dL (IQR 0.5–1.9 mg/dL). Regarding important comorbidities and past medical history, 75.9% had hypertension (HTN), 34.0% diabetes, 20.3% chronic kidney disease (CKD), 68.6% dyslipidaemia and 17.3% heart failure (HF). The median follow-up was 34 months (IQR 22–72). In univariate analysis, CRP was significantly associated with all-cause mortality (HR 1.06 per 1 mg/dL increase, 95% CI 1.04–1.08, p<0.001), as was gender, age, LVEF, STEMI and previous history of diabetes, HTN, CKD or HF. In multivariate analysis, CRP remained significantly associated with the primary endpoint (HR 1.02, 95% CI 1.00–1.05, p=0.033), as did age, LVEF and previous history of HF.

Conclusions

In our study, CRP at admission was an independent risk factor for all-cause mortality following an ACS. This finding indicates that inflammation associated with the acute event has a significant impact in the long-term prognosis. More evidence is needed to determine if treating inflammation (and when, in the course of the disease) could result in better outcomes.

Prognostic significance of percutaneous coronary intervention associated blood loss in acute coronary syndrome

Background

Antiplatelet and anticoagulants are one of the mainstay treatment of acute coronary syndrome (ACS), however they are associated with a significant increase of bleeding risk. While anaemia is a recognized predictor of adverse outcomes, it is unknown if a variation of haemoglobin (HB) levels, even without associated anaemia, has the same impact.

Purpose

The aim of this study was to determine the prognostic impact of HB variation after percutaneous coronary intervention (PCI) in ACS patients.

Methods

Retrospective analysis of 822 consecutive patients admitted due to ACS and treated with PCI, in a single coronary intensive care unit. Delta HB – ΔHB – (HB at admission – HB 24 hours after PCI) was calculated. Clinical variables and therapeutic strategies were examined. The primary endpoint analysed during follow-up was all-cause mortality. Possible predictors for all-cause mortality were assessed by Cox regression models. When statistically significant values were found in univariate analysis, multivariate analysis was used to determine whether ΔHB was independent from other known factors in predicting the outcome.

Results

In the studied sample, 75.4% were male. Mean age was 66.4±13.1. ST-elevation myocardial infarction (STEMI) occurred in 45.5%, non-ST segment elevation myocardial infarction in 42.6% and unstable angina in 11 9% of the studied population. Moderate to severe systolic dysfunction was present in 23.5% of the cases. Regarding comorbidities and past medical history, 76% had hypertension (HTN), 30.3% diabetes, 16.4% chronic kidney disease (CKD), 62.2% dyslipidaemia and 10.5% heart failure (HF). Mean HB at admission was 13.8±1.8 g/dL, mean HB after PCI was 12.9±1.9 g/dL and mean ΔHB was 0.9±1.1 g/dL. The mean follow-up was 51.6±30.6 months. In univariate analysis, ΔHB was significantly associated with all-cause mortality (HR 1.15 per 1 g/dL loss, 95% CI 1.01–1.30, p=0.04), as was HB at admission, HB after PCI, age, sex, diabetes, HTN, dyslipidaemia, CKD and moderate to severe systolic dysfunction. In multivariate analysis, ΔHB remained significantly associated with the endpoint and gained even more statistical power (HR 1.25, 95% CI 1.10–1.43, p<0.01). HB at admission and after PCI, age, CKD and moderate to severe systolic dysfunction were also independent predictors of this outcome.

Conclusions

In our study, irrespective of the admission and discharge HB, ΔHB was associated with more adverse outcomes in patients submitted to PCI. Hence, even patients with a normal HB after PCI have a worse long-term prognosis if a negative variation of HB occurs. This highlights the importance of identifying and optimising all the correctable factors that might lead to an increased bleeding risk.

Funding Acknowledgement

Type of funding sources: None.

Implications of initiating antiseizure drugs prior to the performance of EEG in first epileptic seizures

INTRODUCTION

This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure.

METHOD

We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72hours after the seizure, and the factors related with seizure recurrence.

RESULTS

We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P=.25) or with the risk of recurrence within 6 months (P=.63).

CONCLUSIONS

Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

Direct oral anticoagulants versus vitamin-K antagonists for left ventricular thrombus - a systemic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular (LV) thrombus is a current clinical problem. The incidence of systemic embolism (SE) is up to 16% in these patients and international guidelines recommend anticoagulation with vitamin-K antagonists (VKAs). Data on direct oral anticoagulants (DOACs) for LV thrombus is increasing but still with conflicting results.

Methods

We performed a systematic review and meta-analysis of studies assessing the efficacy of DOACs versus VKAs in LV thrombus resolution, SE events and/or stroke and bleedings events. We systematically searched PubMed and Cochrane database for studies comparing DOACs versus VKAs as anticoagulant strategy for LV thrombus. Random-effects meta-analysis was performed.

Results

Four studies were included: n= 727 patients (DOACs group – 243 patients vs VKAs group – 484 patients).  There is a 40% reduction in the odds for achieving thrombus resolution in the group of patients treated with DOACs (pooled OR 0.60; 95% CI 0.43-0.85; I2 =0%; P = 0.003) - Figure 1A. No difference between groups for the odds of SE and/or stroke was observed during follow-up (pooled OR 1.75; 95% CI 0.92-3.35; I2 =0%; P = 0.09) - Figure 1B. Bleedings events were not different between both anticoagulant strategies (pooled OR 0.65; 95% CI 0.30-1.39; I2= 0%, P = 0.26) - Figure 1C.

Conclusion

Although probably with less efficacy for thrombus resolution, the use of DOAC for LV thrombus does not seem to increase the risk of SE and/or stroke or bleedings events compared to VKAs.

Abstract Figure 1 - Pooled analysis (DOAC vs VKA)

Landscape-scaled strategies can outperform Lévy random searches

Information on the relevant global scales of the search space, even if partial, should conceivably enhance the performance of random searches. Here we show numerically and analytically that the paradigmatic uninformed optimal Lévy searches can be outperformed by informed multiple-scale random searches in one (1D) and two (2D) dimensions, even when the knowledge about the relevant landscape scales is incomplete. We show in the low-density nondestructive regime that the optimal efficiency of biexponential searches that incorporate all key scales of the 1D landscape of size L decays asymptotically as η_{opt}∼1/sqrt[L], overcoming the result η_{opt}∼1/(sqrt[L]lnL) of optimal Lévy searches. We further characterize the level of limited information the searcher can have on these scales. We obtain the phase diagram of bi- and triexponential searches in 1D and 2D. Remarkably, even for a certain degree of lack of information, partially informed searches can still outperform optimal Lévy searches. We discuss our results in connection with the foraging problem.

Statins for venous thromboembolism prevention: old dog, new tricks

Background

Statins are highly effective in preventing major acute cardiovascular events in the setting of atherosclerotic arterial disease. On the other hand, given their antithrombotic and anti-inflammatory properties, statins may also attenuate patients' odds of developing venous thromboembolism (VTE). However, clinical studies have yielded variable estimates of this effect.

Purpose

To perform a meta-analysis designed to evaluate the extent to which statin use influences the rate of subsequent VTE events.

Methods

We systematically searched MEDLINE, Embase, Web of Science, Cochrane Library and Google Scholar for both randomized controlled trials (RCTs) and observational studies addressing the association between statins and VTE risk, published up until December 1, 2019. Manually reviewed references and key investigators interaction via e-mail correspondence were also data sources. RCTs comparing the effects of statin therapy with those of a placebo or no treatment were included, while interventional studies appraising different lipid-lowering pharmacological strategies were not. Observational studies encompassed both cohort and case-control designs. The primary endpoints were general VTE, deep vein thrombosis or pulmonary embolism. Patients with cancer, heart failure and chronic kidney disease (CKD) were further investigated separately. Study-specific relative risks (RRs) were pooled using generic inverse variance outcome meta-analytic technique with a random-effects model.

Results

23 RCTs comprising 118.464 participants, 12 cohort studies encompassing 2.881.184 patients and 9 case-control studies including 354.367 patients were regarded as eligible for quantitative evaluation. Specifically, 5 observational studies comprising 9.656 cancer patients, 3 studies encompassing 9.693 heart failure patients and 4 studies including 4.353 CKD patients were gathered. In RCTs, statin therapy was proven slightly superior to placebo or no treatment in lowering VTE incidence (RR 0.85, 95% CI 0.73–0.99, p=0.04, i2=14%). Observational studies were found to corroborate this effect, with statin treatment resulting in VTE risk reduction overall (RR 0.72, 95% CI 0.64–0.81, p<0.001, i2=84%) and in both cohort (RR 0.86, 95% CI 0.83–0.90, p<0.001, i2=85%) and case-control (RR 0.68, 95% CI 0.57–0.82, p<0.001, i2=80%) designs. This positive effect held true in cancer patients (RR 0.56, 95% CI 0.33–0.95, p=0.03, i2=78%), but not in those with heart failure (RR 0.7, 95% CI 0.42–1.16, p=0.17, i2=2%) and CKD (RR 1.04, 95% CI 0.67–1.60, p=0.87, i2=0%).

Conclusion

Currently available evidence suggests that statins significantly reduce patients' odds of developing VTE. Given their favorable safety profile and low cost, statin treatment should now be considered in high-risk individuals, particularly in those with cancer.

Funding Acknowledgement

Type of funding source: None

Provisional versus 2-stent strategies for coronary bifurcations: is a bird in the hand worth two in the bush?

Background

Among all subsets of coronary artery lesions, bifurcations stand out due to high incidence, demanding percutaneous interventions (PCIs) and poor outcomes. Amid the different PCI strategies, the provisional (PS) approach is generally recommended over 2-stent (TS) techniques, but this paradigm has been challenged.

Purpose

To compare PS with TS for PCI of coronary bifurcation lesions, concerning procedural aspects and both immediate and long-term patient outcomes.

Methods

Retrospective study encompassing patients consecutively referred to a tertiary interventional cardiology unit for coronary angiography, who were found to have at least 1 native bifurcation lesion. According to operator experience and angiographic features, patients were managed with PS or/(and) TS. Procedural aspects regarding radiological variables, angiographic success and immediate complications were reviewed, as were in-hospital outcomes. Besides, clinical follow-up, by clinic appointment or telephone calling, was performed targeting stent failure, target vessel revascularization (TVR), acute coronary syndromes (ACS), heart failure and mortality.

Results

From January 2010 to June 2017, 404 patients with 433 bifurcation lesions were included. Median age was 70 (62–77) years and 25.3% were female. Median follow-up was 2 (1–3) years. Chronic angina was the dominant PCI context (61.3%) with 9.7% presenting with ST-segment elevation myocardial infarction (MI). Medina class 1,1,1 was documented in 54.1% and 64.9% of lesions were hailed as true bifurcations. 303 patients underwent PS, whereas 67 were managed with TS, with TAP (43.3%) and mini-crush (34.3%) as the leading techniques. True bifurcations were more frequently approached with TS (p<0.001), whereas PCI context did not influence procedure selection. Fluoroscopy time (p<0.001), radiation dose (p=0.003) and contrast volume (p=0.009) were higher in the TS subgroup. OCT guidance (p=0.039) was also more common with TS. Angiographic success was uniformly high (95.1% for PS and 97% for TS), while procedural complications, including iatrogenic coronary dissections (7.4%, mostly minor) and slow-reflow (3.5%), were homogenously low. Acute kidney injury and type 4a MI occurred in 14.5% and 32.3%, respectively, also with no difference between groups. As for long-term outcomes, stent failure, encompassing both stent thrombosis (1 event) and restenosis (4.2%), occurred more often with TS (p=0.046), with ACS events (9.5%) following the same trend (p=0.08). In turn, rates of TVR (12.5%), heart failure hospitalization (6.2%) and mortality, regardless of its cardiovascular nature, were similar.

Conclusion

PS outperforms TS during follow-up, particularly due to lower stent failure odds. Thus, this study further supports the concept of PS as the standard approach for coronary bifurcation lesions.

Funding Acknowledgement

Type of funding source: None

Gender in non- ST elevation myocardial infarction and unstable angina: is there any equality?

Background

Historically, women (W) with acute coronary syndrome (ACS) have worse outcomes compared with men (M). This fact may occur due to gender-specific differences in the presentation and management of patients (P), which were mainly observed in studies dealing with ST-segment elevation infarction (STEMI). There seems to be a gap of knowledge in gender-specific differences in non- ST elevation myocardial infarction (NSTEMI) and unstable angina (UA).

Purpose

Assess gender-specific differences in presentation, treatment and outcomes in NSTEMI and UA patients.

Methods

A retrospective cohort study from consecutive ACS patients enrolled in a multicentre national registry from October 2010 to December 2018 was conducted, identifying 11394 P admitted with NSTEMI or UA. Demographic, clinical and treatment variables were compared between male gender and female gender P.

A Cox multivariate regression was performed to evaluate predictor factors of stablished endpoints: mortality at 1-year (1y) and cardiovascular (CV) hospitalization at 1-year.

Results

A total 11394 P were included, 8145 M (71.5%) and 3249 W (28.5%), mean age of 68±13. W, comparing with M, had higher age (72±12 vs 66±13, p=0.001), higher prevalence of hypertension (85% vs 72%, p=0.001) and diabetes (41% vs 34%, p=0.001) and longer time from symptoms to hospital admission (360 minutes vs 297 minutes, p=0.001). Chest pain was less frequent as first symptom in W (85.6% vs 91.3%, p=0.001). In medical treatment, W had higher chance of not having administration of a loading dose of P2Y12 inhibitor (22.1% vs 18.1, p=0.001) and of being medicated with clopidogrel (85.7% vs 82.1%, p=0.002). At discharge, W were less frequently medicated with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (82.6% vs 84.4, p=0.028). Coronary angiography was less frequently performed in W (77.3% vs 85.7%, p=0.001). Coronary artery disease was less frequently found in the female gender (12.4% vs 4.8%, p=0.001).

In-hospital mortality was higher in W (2.9% vs 2.1%), but in the multivariate analysis the female gender was not an independent predictor of in-hospital mortality (OR 1.05 [0.67- 1.65], p=0.823). 1-year mortality was higher in W (9.2% vs 7.3%) and 1-year CV hospitalization was higher in M (16.8% vs 14.4%). After adjusting for covariates in Cox regression analysis, difference was still significant for mortality (HR= 1.274 [1.038 - 1.564], p=0.02) and hospitalization (HR = 0.852 [0.726- 0.998], p=0.047).

Conclusion

In this NSTEMI and UA cohort, there are important gender-specific differences in comorbidities, diagnosis, management and outcomes. Gender was an independent predictor of 1-year mortality and 1-year CV hospitalization, but not an independent predictor for in-hospital mortality.

Funding Acknowledgement

Type of funding source: None

Global longitudinal strain and chronic kidney disease prognostic impact on acute coronary syndrome

Background

Impaired left ventricular ejection fraction (LVEF) and chronic kidney disease (CKD) have been associated with poorer outcomes in acute coronary syndrome (ACS). Increasing evidence on global left ventricular longitudinal strain (GLS) suggests superiority over left ventricular ejection fraction (LVEF) in risk stratification.

Methods

This study was based on a retrospective analysis of consecutive patients admitted to a Coronary Care Unit between 2009 and 2016. Baseline characteristics and echocardiographic parameters, including LVEF, were assessed. For each patient, a two-dimensional speckle tracking of the left ventricle was assessed and average GLS was calculated using 2, 3 and 4-chamber views. Blood creatinine was measured during hospital stay and used to estimate glomerular filtration rate (GFR) with Modification of Diet in Renal Disease (MDRD) equation. A cox regression analysis was performed to determine mortality prediction value of average GLS, LVEF and GFR in this population. Receiver operating characteristic (ROC) curve analysis was conducted and area under the curve (AUC) was estimated.

Results

A total of 85 patients (66.7±12.7 years old; 78.8% males) were enrolled. LVEF mean was 49.4±9.8% and average GLS was −16.0±4.0%. GFR median was 80.0±48.9 ml/min/1.73m2. In cox regression analysis, worse average GLS was associated with greater mortality (HR 0.721; 95% CI 0.599–0.867; P=0.001). GFR was inversely related to death (HR 0.967; 95% CI 0.944–0.991, P=0.008). In cox regression analysis using average GLS and GFR as covariates, both proved to be independent predictors of mortality (for average GLS, HR 0.748; 95% CI 0.610–0.918, P=0.005; for GFR, HR 0.974; 95% CI 0.949–0.999; P=0.044). The AUC of average GLS to predict mortality was 0.78 (P<0.001, sensitivity 50.7% and specificity 100%) and for average GLS and GFR combined was 0.85 (P<0.001, sensitivity 84.0% and specificity 77.8%). Although LVEF proved to be a mortality predictor, the AUC obtained by ROC curve analysis was inferior to average GLS, with statistical significance (P=0.043).

Conclusions

GLS and CKD proved to be independent predictors of mortality in ACS patients. GLS showed superiority when compared to LVEF in risk stratification and in the future it might replace LVEF. The model combining GLS and GFR emphasized the increased risk of CKD patients and how they should be seen as high-risk patients.

ROC curve analysis

Funding Acknowledgement

Type of funding source: None

Isolated apical perfusion defect in SPECT-CT scans, is there any prognostic value?

Background

Myocardial perfusion imaging (MPI) plays a significant role in diagnostic and therapeutic decision making in coronary artery disease (CAD). An isolated apical defect in the 17th segment in SPECT/CT scans is a common finding, sometimes attributed to the apical thinning phenomenon. However, the clinical significance of apical thinning or other isolated apical defects is unknown.

Purpose

The purpose of this study is to assess the prognostic impact of an isolated apical perfusion defect (17th segment) in patients (P) with suspicion of significant CAD.

Methods

A cohort of 612 consecutive P that underwent a MPI test with a SPECT/CT scanner, between January 2017 and December 2017, in a single nuclear medicine centre, was included in this retrospective study.

The inclusion criteria for this study were either a normal perfusion exam (group 1 – G1) or only an isolated apical defect in the 17th segment, either reversible suggesting ischemia (group 2 – G2) or fixed suggesting necrosis (group 3 – G3). Images with and without attenuation correction were analysed. Mean follow-up was 29±4 months.

The chi square test was used for categorical variables, and analysis of variance for continuous variables. Binary logistic regression was used to control for confounding.

Results

A total of 612 P were included (57% male sex, mean age of 69±10) and divided in G1 (n=494, 80.7%), G2 (n=62, 10%) and G3 (n=56, 9.2%). P in G3 had higher body mass index (31±7, p=0.028) and higher prevalence of dyslipidemia (84%, p=0.001), while P in G1 had lower ejection fraction at rest (54±15, p=0.001). There was no association between the presence of isolated apical defect and all- cause mortality (G1 = 7.3% vs G2 = 6.5% vs G3 = 5.4%, p=0.851). There was a statistically significant difference between groups in the referral for coronary angiography in the bivariate analysis (G1 = 7.9% vs G2 = 35.5% vs G3 = 10.7%, p=0.001), but this association did not remain when accounted for potential confounders (angina, ejection fraction, previous CAD and diabetes) – OR=3.94, 95% CI: [0.968–16.093], p=0.056.

In those P that underwent coronary angiography, there was no statistically significant difference between the 3 groups in revascularization of significant CAD (G1 = 38.5% vs G2 = 36.4% vs G3 = 50%, p=0.830). During the follow-up time, 11 P of group 1 suffered an acute coronary syndrome (ACS), but there were no events in group 2 or 3.

Conclusion

Isolated apical myocardial defect on a SPECT/CT exam has no association with all-cause mortality in this patients. There is no significant difference in referral for coronary angiography or need for coronary revascularization between P with normal exams and P with isolated apical defects.

Funding Acknowledgement

Type of funding source: None

Ranolazine as you have never seen it before: an antiarrhythmic for atrial fibrillation

Background

Currently available pharmacological options for rhythm control in atrial fibrillation (AF) are overshadowed by suboptimal efficacy and both frequent and potentially severe adverse events. Recent studies have added evidence to the hypothesis that ranolazine might exert antiarrhythmic effects, particularly in atrial tachyarrhythmias.

Purpose

To perform a systematic review with meta-analysis in order to ascertain the potential role of ranolazine in the management of AF.

Methods

We systematically searched MEDLINE, Embase and Scopus for randomized controlled trials (RCTs) and cohort studies addressing the association between ranolazine and AF outcomes, published up until December 1, 2019. The primary endpoint was incidence of AF, which was evaluated under a ranolazine versus placebo design. In this regard, patients in the setting of postcardiac surgery were further investigated separately. Secondary endpoints included AF cardioversion outcomes, which were addressed through comparison between ranolazine plus amiodarone and amiodarone alone for proportional efficacy and temporal requirements (time-to-cardioversion). The latter analysis was also undertaken in a dose-sensitive fashion (≤1000mg vs. 1500mg of ranolazine). Tertiary endpoints covered AF burden and episodes, in paroxysmal AF patients, and safety outcomes, namely death, QTc interval prolongation and hypotension. Study-specific odds ratios (ORs) were pooled using meta-analytic techniques with a random-effects model.

Results

A total of 10 RCTs comprising 8.109 participants and 3 cohort studies encompassing 37.112 patients were regarded as eligible for evaluation. Ranolazine was found to attenuate patients' odds of developing AF (OR 0.53, 95% CI: 0.41–0.69, p<0.001, i2=58%). This effect held true, with an even larger effect size, in the context of post-cardiac surgery (OR 0.34, 95% CI: 0.16–0.72, p=0.005, i2=64%). Ranolazine increased the chances of successful AF cardioversion when added to amiodarone over amiodarone alone (OR 6.67, 95% CI: 1.49–29.89, p=0.01, i2=76%), while significantly reducing time-to-cardioversion [SMD 9.54h, 95% CI: −13.3–5.75, p<0.001, i2=99%]. Interestingly, cardioversion was faster with ≤1000mg of ranolazine (SMD −13.16h, 95% CI: −15.07–11.25, p<0.001, i2=95%) than with 1500mg (SMD −3.57h, 95% CI: −5.06–2.08, p<0.001, i2=23%). In paroxysmal AF, ranolazine was also proved to significantly reduce both AF burden and episodes. There were no safety signals regarding mortality odds, QTc interval prolongation (mostly clinically insignificant) and hypotension (mostly transitory).

Conclusion

Current evidence suggests that ranolazine provides an effective and safe option for a chemical rhythm control strategy in AF management, a field in which medical breakthroughs are desperately needed.

Funding Acknowledgement

Type of funding source: None

How soon should urgent EEG be performed following a first epileptic seizure?

PURPOSE

Patients with a first unprovoked epileptic seizure are often seen in emergency services. Electroencephalography (EEG) is indicated for diagnosing epilepsy, but the optimal time to perform this test has not been defined. This study aimed to determine the time interval following a seizure within which EEG has the greatest diagnostic yield.

METHODS

We conducted a retrospective study of all adult patients with a first unprovoked seizure who had undergone emergency EEG (July 2014-December 2019). Data collection included demographics, seizure type, time interval to EEG study, EEG pattern identified, and the prescription after emergency assessment. An optimal cut-off point for time to EEG was obtained, and an adjusted regression model was performed to establish associations with the presence of epileptiform abnormalities.

RESULTS

A total of 170 patients were included (mean age: 50.7 years, 40.6% women). Epileptiform discharges were identified in 34.1% of recordings, nonepileptiform abnormalities in 46.5%, and normal findings in 19.4%. A lower latency from seizure to EEG was associated with a higher probability of finding epileptiform discharges (median: 12.7 in the epileptiform EEGs vs. 20 h in the nonepileptiform EEGs, p < 0.001). The time interval associated with the highest probability of detecting an epileptiform EEG pattern was within the first 16 h after seizure onset: 52.1% of recordings performed before the 16-h cut-off showed these abnormal patterns compared with 20.2% performed after (p < 0.001). These findings were not related to the presence of an epileptogenic lesion in neuroimaging or to other clinical variables. The finding of epileptiform abnormalities was followed by a greater prescription of antiseizure drugs (96.4% vs. 66% in nonepileptiform patterns, p < 0.001).

CONCLUSION

The diagnostic yield of EEG following a first unprovoked epileptic seizure is highest when this test is performed within the first 16 h after onset of the event.

Monitoring of the oxidation of the oil from sacha inchi (

This work focuses on the characterization of the oxidation of the oil from sacha inchi seeds (Plukenetia volubilis) under accelerated conditions at 60 ºC for 15 days. Five samples were monitored: three supplemented with 200 ppm of non-hydrolyzed or partially hydrolyzed (for 4 and 9 hours) extracts from tara (Caesalpinia spinosa) pods, one without antioxidant and one with 200 ppm of BHT. Several conventional tech­niques (induction time, peroxide value, conjugated dienoic acid, p-anisidine value, total unsaturated fatty acids and α-linolenic acid contents) and the MIR spectroscopy coupled with chemometric tools were used and com­pared. The results revealed that whatever the antioxidant added, the oil from sacha inchi is fairly stable over time. The results also pointed out that extracts from tara pods, mainly those partially hydrolyzed, were more efficient than BHT against oil oxidation for up to 7 days. Finally, this paper shows that MIR spectroscopy pres­ents an interesting alternative technique for the monitoring of the oxidation of the oil from sacha inchi.

P1092Syncope in the emergency department: can 24-hour holter monitoring be of any help?

Background 

Syncope is a very common reason for presenting to the emergency department (ED). The existence of a telemetry unit is crucial but it is not the reality in some hospitals. In order to avoid unnecessary ward admission, 24-hour Holter (24HH) monitoring could be useful to help with the diagnosis (when the arrhythmic etiology is suspected and the symptoms are frequent enough) and also be important to safely discharge a patient. 

Purpose 

The purpose of this study is to evaluate the diagnostic performance of 24HH monitoring, during a syncope episode in the ER, and to compare the readmission rates between patients with normal and abnormal not diagnostic 24HH monitoring. 

Methods 

A cohort study of consecutive patients (P) who were monitored with 24HH in one hospital in the ED, between January 2015 and December 2017, were included. All the 24HH results were seen by a senior cardiologist and divided in three groups: A - normal, B - abnormal Holter study unlikely to explain syncope and C- Holter study considered to be diagnostic. 

Groups A and B were compared using chi-square independence test to evaluate association between the result of the 24HH and readmission rates at 30 days and 1 year, as well as mortality and device implantation at 1 year. Multivariate logistic regression was used to look for other confounders. 

Results 

A total of 111 P were included in this study. Mean age was 75 ± 14 years old, with 55.6% male patients. 

A previous emergency episode with syncope was present in 56.9% of P. The mortality at one-year follow-up was 11.9%. The 24HH was considered diagnostic in 25.2% of P (28 P), with 18.9% of all the P with necessity of pacemaker (PM) implantation. In the patients with a non-diagnostic 24HH, 6,4% implanted a loop recorder before discharge. 

Group B patients had a higher 30-day readmission rate to the ED when compared with group A (OR = 4.050 CI 95 [1.13 – 14.497], p = 0.033), but no difference in one-year readmission rate (p= 0.065). There was no difference in one-year mortality between the two groups (p= 0.731) or in one-year implantation of pacemaker (p= 0.431). 

Conclusion 

The use of 24HH in the ED could be a valuable tool in the diagnosis of rhythm disorders that cause syncope.  An abnormal non diagnostic result can still be a predictor of 30-day readmission to the ED with similar complaints.

P1433Prevalence and location of residual leaks following percutaneous left atrial appendage occlusion: the importance of 3D transesophageal echocardiography

Background

The left atrial appendage (LAA) shape and size are very variable, and incomplete appendage closure or persistent leaks around the device are common following device placement. Limited studies reported the rate of peri-device leaks (PDL) after percutaneous left atrial appendage closure, and the impact of 3D transesophageal echocardiography (3D-TEE) on the detection of those leaks.

Aim

To describe the rate and location of leaks 1 month after percutaneous closure of the LAA, with and without the use of 3D-TEE.

Methods

A cohort study of consecutive patients (P) who were submitted to a percutaneous LAA closure with success in one interventional cardiology centre, between May 2010 and October 2018, were included. Clinical and echocardiography data were recorded and analysed. Two groups were created: Group A (GA) included patients until August 2015 submitted to 2D TEE on follow up (N= 48) versus Group B (GB), which was composed of patients submitted to 3D-TEE after August 2015 (N= 76).

Results

A total of 124 P had an in-hospital admission for LAA closure, with control TEE 1 month after the procedure. Mean age was 73 ± 7 years old, with 62.9% male patients. The procedure was guided by TEE (52%) or intra cardiac echocardiography (ICE) (48%).Transeptal puncture was preferred (95% of the procedures). The most used device was Amulet (62%) vs ACP (23%) and Watchman (15%).

In the follow up TEE, 20% of patients had only 1 leak and 2% had 2 leaks. Of the detected leaks,31% were considered minor (&lt; 1 mm), 35% moderate (1-3 mm) and 34% major (&gt; 3 mm). Patients with leaks had a larger LAA diameter (22 ± 4 mm vs. 17 ± 3 mm, P = 0.01).

Of the detected leaks, 50% were located in the superior portion of the device, 23% were located in the inferior portion, 8% in the posterior portion and 8% in the lateral portion.

In GA the rate of leaks was 14% vs 24.5% in GB, with differences also when specified the size of the leak –  minor (GA 2% vs GB 8.8%), moderate (GA 8% vs GB 8.1%) and major (GA 4% vs GB 7.6%).

Conclusion

The use of 3D echocardiography, 1 month after successful percutaneous LAA closure, augmented the rate of detection of device leaks. It remains to be studied the clinical impact of this finding.

Do microplastics affect the zoanthid Zoanthus sociatus?

Microplastics (1 μm-5 mm), a ubiquitous and persistent marine pollutant, pose a severe threat to coral reefs when recently associated with physiological distress and increased diseases on corals. Studies conducted so far have only reported effects on scleractinian species. Knowledge about its effects on other corals (e.g. Order Zoantharia) remains uncovered, and responses at biochemical levels remain poorly documented. This study aimed to assess the potential effects induced by the presence of microplastics (1 and 10 mg L^-1 low-density polyethylene, LDPE MP, or polyvinyl chloride, PVC MP) in the tropical and subtropical cosmopolitan species Zoanthus sociatus (order Zoantharia. Anthozoa: Hexacorallia), at organism level (survival and behaviour), endosymbionts (photosynthetic efficiency) and the cellular level (oxidative stress, detoxification capacity and energy metabolism). In a short-term exposure (96 h), this species was more sensitive to PVC MP. The presence of this polymer at a concentration of 10 mg L^-1 caused a ten-fold higher adhesion to the coral epidermis, increased photosynthetic efficiency, lipid peroxidation, and antioxidant defences; without, however, inducing energetic costs. Although the observed physiological and biochemical effects did not compromise Z. sociatus survival in the short term, it does not rule out potential long-term (cumulative) effects that could endanger this and other physiologically similar species that underlie coral reefs.

A description of the growth and moulting of feathers in commercial broilers

1. Changes in feather length and weight and daily losses of down, contour feathers, remiges and retrices were studied in two commercial broiler strains to determine feather growth and moult in broilers up to 112 d of age. 2. Ten pens of 20 chicks for each sex x strain were fed adequate amounts of dietary protein in a four-phase feeding programme. Ten birds were sampled per genotype at 14, 28, 42, 56, 70, 84, 98 and 112 d. Feather loss was determined for individual birds caged within a nylon net. 3. All feathers were dry-plucked from each of seven tracts, with representative feathers from the capital-cervical, dorsopelvic and interscapular, pectoral and femoral tracts being randomly selected. Three rectrices of the dorsocaudal tract and three primaries and secondaries of the humeral-alar tract of the right wing were evaluated. 4. The length of the selected feathers was measured, and the feathers from each tract and from the whole bird were weighed. 5. A wide range of rates of maturing (0.0250-0.0907/d) and mature weights (9.62-52.9 g) were evident between sampled tracts. 6. Feather weight failed to predict some moults which were detected by the measurement of feather losses. From the weight data, moulting was evident only in the humeral-alar and dorsocaudal tracts, whereas, when daily losses were measured, contour feathers accounted for over 0.7 proportion of feather losses. Logistic equations adequately described the cumulative losses of down, contour feathers and remiges. 7. Feather loss needs to be considered when feather growth is determined from feather weight at different ages. 8. The rate of maturing (B) of feathers was numerically higher in Ross males and females than in the Cobb strain. In females, B was higher than in males (0.0483 vs. 0335/d) but the mature weight was lower (162 vs. 230 g).

Lethal and sublethal toxicity assessment of Bacillus thuringiensis var. israelensis and Beauveria bassiana based bioinsecticides to the aquatic insect Chironomus riparius

Despite being considered environmentally safe, a deeper environmental risk assessment is needed for microbial insecticides; special attention should be devoted to their sublethal toxicity to non-target species. This study evaluated effects of VectoBac® 12AS - VB (based on the bacterium Bacillus thurigiensis var. israelensis) and Naturalis®-L - NL (based on the fungus Beauveria bassiana) on the aquatic insect Chironomus riparius life-history and biochemical responses. Acute tests estimated a 48 h-LC₅₀ (median lethal concentration) of 1.85 μg/L (VB) and 34.7 mg/L (NL). Under sublethal exposure, VB decreased adults' emergence (LOEC - lowest observed effect concentration of 80 ng/L) while NL impaired larval growth (LOEC of 0.32 mg/L) and delayed emergence (LOEC of 2 mg/L for males and 0.8 mg/L for females). Despite not being monotonic, phenoloxidase activity increased (LOEC of 20 ng/L (VB) and 2 mg/L (NL)), suggesting activation of the immune system. There were no indications of oxidative damage nor neurotoxicity. Catalase activity was stimulated with all VB treatments, possibly associated with detoxification of immune response products. Under NL exposure, glutathione-S-transferase activity increased but did not show a dose-dependent response and, total glutathione decreased in the highest concentration. Exposure to both formulations caused the increase in protein content, while carbohydrate and lipids were not altered. This study revealed the susceptibility of C. riparius to VB and NL at concentrations below the ones recommended for field application, with potential population-level effects. These results add important information for the risk assessment of these microbial insecticides in aquatic ecosystems, considering relevant sublethal endpoints and raising concern about the adverse effects on non-target aquatic organisms.

P621Variation of global longitudinal strain (2D STE) with passive leg lifting maneuver: a marker of myocardial functional reserve?

Introduction

In a normal heart, the passive leg lifting maneuver (LLM) will result in an increase in myocardial contractility, according to the mechanistic concept of the Frank-Starling law. With the progression of myocardial disease this ability is impaired and the myocardial functional reserve (mFR) is reduced (Figure1 – Panel A). The variation of left ventricular global longitudinal strain (as an index of contractile function) with LLM may thus represent a marker of left ventricular mFR.

Purpose

To assess the variation of left ventricular global longitudinal strain (LV GLS) with LLM as a marker of mFR in a healthy population and in patients with myocardial disease (hypertrophic myocardiopathy - HCM and systolic dysfunction patients – SystDysf.

Methods and results

We evaluated the variation of LV GLS by 2-dimensional Speckle Tracking Echocardiography (2D-STE), in response to passive LLM, in a population of 103 individuals (54 healthy individuals, 28 HCM patients and 21 left ventricular SystDysf patients). Clinical, demographic and echocardiographic parameters (including LV longitudinal mechanics obtained with 2D-STE before and after LLM) were described. The population had a mean age of 46±18 years and 55% were women. Increased venous return to the heart during LLM was confirmed by an increase in the maximal diameter of the inferior vena cava (15,1±3,6 vs 20,6±3,8 mm, p<0.001).

There was a significant variation of LV GLS in healthy individuals submitted to LLM (−20,58±3,0 vs −21,5±2,6%, p=0,02, Δ 0,6%, 95% CI 0,1–1,1%). Regarding the HCM and SystDysf groups, no significant change in LV GLS was observed with LLM (−13,2±2,8 vs −12,3±2,9%, p=0,12, Δ +0,6%, 95% CI −1,4 to 0,18% and −10,2±2,5 vs 10,2±2,7%, p=0,79, Δ 0,08%, 95% CI −0,7 to 0,5%, respectively). Figure 1 (Panel B)

Conclusion

To our knowledge, this is the first report describing the use of LV GLS and LLM to assess mFR in this clinical setting. The absolute increase of LV GLS in the healthy population suggests that this may be a reliable method and a sensitive marker to assess the mFR. Conversely, patients with HCM and with SystDysf show poor or no response to the LLM, suggesting, as expected, a low myocardial functional reserve. Given the non-invasiveness and cost-effectiveness nature of this technique, we suggest that this maneuver could pose a feasible way to assess mFR. Further studies are needed to validate this technique and to assess the role of mFR by 2D-STE as a prognostic marker.

P6447Prediabetes versus diabetes mellitus in acute coronary syndrome patients: two sides of the same coin

Background

Prediabetic patients are at increased risk of composite cardiovascular (CV) events and all-cause mortality. The impact of prediabetes diagnosis in the context of an acute coronary syndrome (ACS) remains to be determined.

Purpose

To assess the differences on long-term mortality between well controlled diabetic and prediabetic patients admitted with non-ST elevation ACS.

Methods

352 non-ST elevation ACS patients admitted to a single coronary care unit between 2009 and 2016 were included. Clinical, laboratorial and echocardiographic data were evaluated. Two groups were created based on the diabetic status and HBA1c level: Group A (prediabetic patients, HBA1c between 5.7–6.4%) N=229; Group B (diabetic patients, HBA1c ≤7%) N=123. The primary endpoint was long-term all-cause mortality. Kaplan-Meyer survival curves and Cox regression were done. The mean time of follow up was 48±30 months.

Results

The groups were similar regarding demographics, CV risk factors, ACS type, heart failure diagnosis, peak troponin I, left ventricular (LV) systolic function, multivessel disease and treatment option (PCI, CABG or OMT). On the contrary, well controlled diabetic patients had a higher prevalence of chronic kidney disease (CKD) (27.9% vs 39.0%, P<0.05), hypertension (82.5% vs 91.9%, P<0.05), higher body mass index (BMI) (23±4 vs 24±4 kg/m2, P<0.05) and previous coronary artery disease (37.1% vs 51.2%, P<0.05). 95 patients met the primary outcome. Kaplan-Meyer curves showed a tendency to decreased survival in the diabetic group (72.8% vs 66.4%, Log Rank P=0.09 – Figure 1). After adjustment for age, CKD, BMI (6 categories), heart failure diagnosis, peak troponin I and LV systolic function, controlled diabetes was not associated with increased death (HR 1.40, 95% CI 0.87–2.26). In this model, only age (HR 1.05, 95% CI 1.02–1.08), peak troponin (HR 1.01, 95% CI 1.00–1.01) and moderate to severely impaired LV function (HR 2.00, 95% CI 1.12–3.56) remained associated with the outcome.

Conclusion

In the context of an ACS, prediabetics should be regarded as a high-risk group. This study raises the provocative question that prediabetics and diabetics patients should be approached in similar ways in terms of risk stratification and therapeutic options after an ACS. In these patients, age, peak troponin and impaired LV function appear to be the main contributors to decreased survival.

P5499Coronary angioplasty for octogenarian acute coronary syndrome patients? Is it worth it?

Background

As the population ages, doctors are being challenged by the decision to offer intervention treatment in increasingly older and fragile patients. The comorbidity burden and performance status should be considered when making the decision.

Purpose

To assess the impact of optimal medical therapy (OMT) versus percutaneous coronary intervention (PCI) in non-ST elevation acute coronary syndrome (ACS) patients older than 80 years.

Methods

182 patients older than 80 years old admitted to a single coronary care unit with a diagnosis of non-ST elevation ACS, who survived hospital stay were included. Clinical, laboratorial and echocardiographic data were evaluated. Two groups were created: Group A (OMT group) N=83; Group B (PCI group) N=99. The primary endpoint was long-term all-cause mortality. Kaplan-Meyer curves and Cox regression were conducted to evaluate the impact of OMT versus PCI on the primary endpoint. The mean time of follow-up was 37±29 months.

Results

Groups were homogenous regarding gender, cardiovascular risk factors, heart failure diagnosis, left ventricular (LV) systolic function and peak troponin I. OMT group patients were older (85.1±3.7 vs 82.7±3.2 years old, P<0.01), had a higher prevalence of chronic kidney disease (CKD) (61.4% vs 46.5%, P<0.05), a lower haemoglobin (Hb) level (12.0±1.9 vs 12.6±1.7 g/dL, P<0.05) and were less likely to receive double antiplatelet therapy at discharge (80.8% vs 100%, P<0.001). 84 patients met the primary outcome. Kaplan-Meyer curves showed increased survival in the PCI group (36.5% vs 59.3%, Log Rank P<0.001 – Figure 1). Nevertheless, PCI was not associated with long-term mortality (HR 1.05, 95% CI 0.98–1.12) in a model adjusted for age, CKD, peak troponin, LV systolic function and Hb level. Only Hb (HR 0.81, 95% CI 0.73–0.93), peak troponin (HR 1.01, 95% CI 1.00–1.01) and LV function (slightly impaired [HR 1.89, 95% CI 1.03–3,48] and moderate/severely impaired [HR 1.96, 95% CI 1.14–3.36]) remained associated with the outcome.

Conclusion

Increased survival in older patients receiving PCI after a non-ST elevation ACS may be ascribed to the selection of patients with less comorbidities. This reinforces the idea it may be applied in well-fit patients regardless of age. In our elderly population, lower Hb level, peak troponin and impaired LV systolic function appear to be the main contributors to decreased survival, irrespective of intervention.

Self-crosslinked fibrous collagen/chitosan blends: Processing, properties evaluation and monitoring of degradation by bi-fluorescence imaging

Porous collagen/chitosan scaffolds with different Collagen:Chitosan (Coll:Ch) ratios were prepared by freeze-drying followed by self-crosslinking via dehydrothermal treatment (DHT) and characterized as biomaterials for tissue engineering. Cy7 and Cy5.5 fluorochromes were covalently grafted to collagen and chitosan, respectively. Thus, it was possible, using optical fluorescence imaging of the two fluorochromes, to simultaneously track their in vivo biodegradation, in a blend scaffold form. The fluorescence signal evolution, due to the bioresorption, corroborated with histological analysis. In vitro cytocompatibility of Coll:Ch blend scaffolds were evaluated with standardized tests. In addition, the scaffolds showed a highly interconnected porous structure. Extent of crosslinking was analyzed by convergent analysis using thermogravimetry, Fourier Transform Infrared Spectroscopy and PBS uptake. The variations observed with these techniques indicate strong interactions between collagen and chitosan (covalent and hydrogen bonds) promoted by the DHT. The mechanical properties were characterized to elucidate the impact of the different processing steps in the sample preparation (DHT, neutralization and sterilization by β-irradiation) and showed a robust processing scheme with low impact of Coll:Ch composition ratio.

Protein synthesis is lowered by 4EBP1 and eIF2-α signaling while protein degradation may be maintained in fasting, hypoxic Amazonian cichlids Astronotus ocellatus

The Amazonian cichlid Astronotus ocellatus is highly tolerant to hypoxia, and is known to reduce its metabolic rate by reducing the activity of energetically expensive metabolic processes when oxygen is lacking in its environment. Our objectives were to determine how protein metabolism is regulated in A. ocellatus during hypoxia. Fish were exposed to a stepwise decrease in air saturation (100%, 20%, 10% and 5%) for 2 h at each level, and sampled throughout the experiment. A flooding dose technique using a stable isotope allowed us to observe an overall decrease in protein synthesis during hypoxia in liver, muscle, gill and heart. We estimate that this decrease in rates of protein synthesis accounts for a 20 to 36% decrease in metabolic rate, which would enable oscars to maintain stable levels of ATP and prolong survival. It was also determined for the first time in fish that a decrease in protein synthesis during hypoxia is likely controlled by signaling molecules (4EBP1 and eIF2-α), and not simply due to a lack of ATP. We could not detect any effects of hypoxia on protein degradation as the levels of NH₄ excretion, indicators of the ubiquitin proteasome pathway, and enzymatic activities of lysosomal and non-lysosomal proteolytic enzymes were maintained throughout the experiment.

EARLY-ESLI study: Long-term experience with eslicarbazepine acetate after first monotherapy failure

PURPOSE

Evaluate real-life experience with eslicarbazepine acetate (ESL) after first monotherapy failure in a large series of patients with focal epilepsy.

METHOD

Multicentre, retrospective, 1-year, observational study in patients older than 18 years, with focal epilepsy, who had failed first antiepileptic drug monotherapy and who received ESL. Data from clinical records were analysed at baseline, 3, 6 and 12 months to assess effectiveness and tolerability.

RESULTS

Eslicarbazepine acetate was initiated in 253 patients. The 1-year retention rate was 92.9%, and the final median dose of ESL was 800 mg. At 12 months, 62.3% of patients had been seizure free for 6 months; 37.3% had been seizure free for 1 year. During follow-up, 31.6% of the patients reported ESL-related adverse events (AEs), most commonly somnolence (8.7%) and dizziness (5.1%), and 3.6% discontinued due to AEs. Hyponatraemia was observed in seven patients (2.8%). After starting ESL, 137 patients (54.2%) withdrew the prior monotherapy and converted to ESL monotherapy; 75.9% were seizure free, 87.6% were responders, 4.4% worsened, and 23.4% reported ESL-related AEs.

CONCLUSION

Use of ESL after first monotherapy failure was associated with an optimal seizure control and tolerability profile. Over half of patients were converted to ESL monotherapy during follow-up.

Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study

BACKGROUND

Prebiotics have been shown to reduce abdominal symptoms in patients with functional gut disorders, despite that they are fermented by colonic bacteria and may induce gas-related symptoms.

AIM

To investigate changes in the metabolic activity of gut microbiota induced by a recognised prebiotic.

METHODS

Healthy subjects (n = 20) were given a prebiotic (2.8 g/day HOST-G904, HOST Therabiomics, Jersey, Channel Islands) for 3 weeks. During 3-day periods immediately before, at the beginning and at the end of the administration subjects were put on a standard diet (low fibre diet supplemented with one portion of high fibre foods) and the following outcomes were measured: (i) number of daytime gas evacuations for 2 days by means of an event marker; (ii) volume of gas evacuated via a rectal tube during 4 h after a test meal; and (iii) microbiota composition by faecal Illumina MiSeq sequencing.

RESULTS

At the beginning of administration, HOST-G904 significantly increased the number of daily anal gas evacuations (18 ± 2 vs. 12 ± 1 pre-administration; P < 0.001) and the volume of gas evacuated after the test meal (236 ± 23 mL vs. 160 ± 17 mL pre-administration; P = 0.006). However, after 3 weeks of administration, these effects diminished (11 ± 2 daily evacuations, 169 ± 23 mL gas evacuation). At day 21, relative abundance of butyrate producers (Lachnospiraceae) correlated inversely with the volume of gas evacuated (r = -0.52; P = 0.02).

CONCLUSION

The availability of substrates induces an adaptation of the colonic microbiota activity in bacterial metabolism, which produces less gas and associated issues. Clinical trials.gov NCT02618239.

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

BACKGROUND

Biomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration.

RESULTS

We evaluated a commercially available PV system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C₂C₁Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that >99.9 wt% [C₂C₁Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses.

CONCLUSIONS

These findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.

Optimal search strategies of space-time coupled random walkers with finite lifetimes

We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ω(m). While still alive, the creeper has a finite mean frequency ω of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ω(m)-dependent optimal frequency ω=ω(opt) that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d=1) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d=2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d=1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

Abstract P4-16-09: Phase 1b/2 trial of the HER3 inhibitor patritumab (U3-1287) in combination with trastuzumab plus paclitaxel in newly-diagnosed patients with HER2+ metastatic breast cancer (MBC)

Background: Patritumab is a fully human anti-HER3 monoclonal antibody that has shown potent antitumor activity in vivo. HER3 is a key dimerization partner for other HER family members, and studies suggest that the HER3:HER2 heterodimer is the most potent signaling pair. Therefore, combined inhibition of HER3 and HER2 may synergistically inhibit breast cancer tumor growth. In the CLEOPATRA trial, pertuzumab combined with trastuzumab and docetaxel prolonged progression-free survival compared to trastuzumab and docetaxel alone, demonstrating the benefit of comprehensive blockade of HER2 dimer signaling. Trastuzumab is approved in combination with paclitaxel for first-line treatment of HER2+ MBC. This phase 1b/2 study is investigating patritumab in combination with trastuzumab and paclitaxel in patients (pts) with newly-diagnosed MBC. Results of the phase 1b portion are reported here.

Methods: Eligible pts had HER2+ newly-diagnosed MBC. In the open-label, phase 1b portion of this trial, pts received intravenous (IV) patritumab 18 mg/kg in combination with trastuzumab (8 mg/kg IV loading dose; 6 mg/kg IV maintenance dose) and paclitaxel (175 mg/m2 IV) every 3 weeks (Q3W). In the event that 18 mg/kg was not tolerated based on dose-limiting toxicity (DLT) assessment, sequential cohorts were to receive de-escalating doses of patritumab. Phase 1b study end points included adverse event (AE) incidence, human antihuman antibody (HAHA) formation, pharmacokinetics (PK), and tumor response.

Results: Six pts were enrolled in the phase 1b portion of the trial, with a median age of 61 years (range, 51-78). There were no reported DLTs. Grade ≥3 treatment-related AEs occurred in 3 pts: 1 pt had a serious AE of grade 3 pneumonia; 1 pt had grade 3 worsening of arm pain; 1 pt had grade 3 oral mucositis, prolonged QTc, flu-like syndrome, and increased transaminases. In this limited pt population, most ECG changes were within or slightly above normal limits of the QTc interval. Only 2 pts had increased values close to 50 msec compared with baseline. It should be noted that baseline QTc values for 3 pts (including the pt that experienced grade 3 prolonged QTc) were close to the upper limit of normal. There were no grade 4 AEs, and no other serious AEs. All other treatment-related AEs were grades 1 or 2. All 6 pts tested negative for HAHA formation after drug administration. PK data are consistent with previous studies with patritumab. Two pts had complete response (CR) as their best overall response, 2 pts had partial response (PR), 1 pt had stable disease, and 1 pt was not evaluated for tumor response. All 6 pts have discontinued treatment; 2 due to progressive disease, 3 due to pt decision (2 with CR and 1 with PR), and 1 at the investigator's discretion.

Conclusions: Results to date indicate that the combination of patritumab with trastuzumab and paclitaxel is generally well tolerated, with a promising response rate. As no DLTs were reported, the recommended phase 2 dose is patritumab 18 mg/kg with trastuzumab (8 mg/kg loading; 6 mg/kg maintenance) and paclitaxel 175 mg/m2 Q3W.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-09.