Understanding the In Vitro-In Vivo Nexus: Advanced correlation models predict clinical performance of liposomal doxorubicin

In the century of precision medicine and predictive modeling, addressing quality-related issues in the medical supply chain is critical, with 62 % of the disruptions being attributable to quality challenges. This study centers on the development and safety of liposomal doxorubicin, where animal studies alone often do not adequately explain the complex interplay between critical quality attributes and in vivo performances. Anchored in our aim to elucidate this in vitro-in vivo nexus, we compared TLD-1, a novel liposomal doxorubicin delivery system, against the established formulations Doxil® and Lipodox®. Robust in vitro-in vivo correlations (IVIVCs) with excellent coefficients of determination (R2 > 0.98) were obtained in the presence of serum under dynamic high-shear conditions. They provided the foundation for an advanced characterization and benchmarking strategy. Despite the smaller vesicle size and reduced core crystallinity of TLD-1, its release behavior closely resembled that of Doxil®. Nevertheless, subtle differences between the dosage forms observed in the in vitro setting were reflected in the bioavailabilities observed in vivo. Data from a Phase-I clinical trial facilitated the development of patient-specific IVIVCs using the physiologically-based nanocarrier biopharmaceutics model, enabling a more accurate estimation of doxorubicin exposure. This advancement could impact clinical practice by allowing for more precise dose estimation and aiding in the assessment of the interchangeability of generic liposomal doxorubicin.

An extremely energetic cosmic ray observed by a surface detector array

Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting areas. In this work, we report the detection of an extremely energetic particle recorded by the surface detector array of the Telescope Array experiment. We calculate the particle's energy as [Formula: see text] (~40 joules). Its arrival direction points back to a void in the large-scale structure of the Universe. Possible explanations include a large deflection by the foreground magnetic field, an unidentified source in the local extragalactic neighborhood, or an incomplete knowledge of particle physics.

Adaptation of a Clinical Proton Pencil Beam Scanning System for FLASH Experiments

PURPOSE/OBJECTIVE(S)

To characterize a proton pencil beam scanning system for ultra-high dose rate (UHDR) irradiations and validate it with FLASH preclinical experiments.

MATERIALS/METHODS

After modifications to the beamline to maximize the beam current at isocenter in our gantry room, we characterized the UHDR beam in terms of: 1) Size and shape of the beam spot in three configurations; pristine beam, 75 mm water-equivalent-thickness (WET) range shifter (RS), and custom-built 135 mm WET RS mounted 310 mm upstream of the aperture in the snout housing. These configurations were analyzed to determine which one achieved the highest dose rate; 2) Beam transport efficiency and beam output. We compared the signal in the monitor chambers of the proton system with a Faraday cup and plane parallel ionization chamber (PPC05, IBA dosimetry) for beam current at the cyclotron from 7.5 nA to 800 nA; 3) Dose homogeneity, beam penumbra, and dose rate for the fields to be used in preclinical irradiations. All measurements were performed at isocenter, in air or at 1 cm depth in solid water, using the highest energy (about 230 MeV), which corresponded to a nominal range of 32.9 cm in water. We modeled the UHDR beam in our treatment planning system (TPS) to optimize the dose homogeneity and lateral penumbra of the irradiation fields. We performed the preclinical experiments in single fractions of 19 Gy (RBE), 21 Gy (RBE) and 23 Gy (RBE) (RBE = 1.1), targeting the pelvis of C57BL/6 mice and using survival as the endpoint. Each arm included 6-10 mice. The proton beam was used in transmission mode, positioning the center of the mouse pelvis at isocenter, and irradiating the pelvis with a 2x6 cm^2 field. Apertures were placed at 9cm from the isocenter to sharpen the lateral penumbra.

RESULTS

The range measurements with a multi-layer ionization chamber were consistent within 1 mm with the nominal range. In UHDR mode, the spot size at the isocenter varied from 4.5 mm for the pristine beam to 9.2 mm for the 135 mm RS. The spot size at isocenter remained constant when the beam intensity varied from 7.5 nA to 800 nA at the cyclotron exit. By employing the configuration with the 135 mm RS and optimizing the fields in the TPS, we achieved a dose rate of 1 Gy (RBE)/s for the conventional regime and 75(RBE) Gy/s for the UHDR regime. The monitor chambers of the proton system were affected by recombination at high dose rates: we observed about 35% higher output for the same number of monitor units delivered at 800 nA vs 7.5 nA. The delivered dose was determined with the PPC05 for each field, as this detector did not show recombination effects. When preclinical irradiations were independently monitored, the delivered dose was typically within 1% of the intended value. In three independent experiments, a dose of 21 Gy (RBE) or higher was associated with an increased survival in the UHDR arm compared to the conventional arm.

CONCLUSION

We adapted a clinical proton system for preclinical irradiations at UHDR. Our results confirm the presence of the FLASH effect.

Gadoxetic acid in hepatocellular carcinoma and liver metastases: pearls and pitfalls

Gadoxetic disodium (Primovist) is a hepatocyte-specific magnetic resonance imaging (MRI) contrast agent with increasing popularity with its unique dual dynamic and excretory properties in focal liver lesion detection and characterisation. In-depth knowledge of its diagnostic utility and pitfalls in hepatocellular carcinoma (HCC) and liver metastases is crucial in facilitating clinical management. The current article reviews the pearls and pitfalls in these aspects with highlights from the latest research evidence. Pearls for common usage of Primovist in HCC includes detection of precursor cancer lesions in cirrhotic patients. Hepatobiliary phase hypointensity precedes arterial phase hyperenhancement (APHE) in hepatocarcinogenesis. Hepatobiliary phase hypointense nodules without APHE can represent early or progressed hepatocellular carcinoma (HCC) and high-grade dysplastic nodules. In addition, Primovist is useful to differentiate HCC from pseudolesions. Pitfalls in diagnosing HCC include transient tachypnoea in the arterial phase, rare hepatobiliary phase hyperintense HCC, and decompensated liver cirrhosis compromising image quality. Primovist is currently the most sensitive technique in diagnosing liver metastases before curative hepatic resection. Other patterns of enhancement of liver metastases, "disappearing" liver metastases are important pitfalls. Radiologists should be aware of the diagnostic utility, limitations, and potential pitfalls for the common usage of hepatobiliary specific contrast agent in liver MRI.

Filtration performance of three models of N95 filtering facepiece respirators following clinical usage and vaporized hydrogen peroxide decontamination

BACKGROUND

N95 filtering facepiece respirators (FFRs) are essential personal protective equipment (PPE) for protecting healthcare workers from airborne pathogens.

AIM

To perform the first large-scale evaluation of particulate filtration efficiency (PFE) of three models of N95 FFRs following clinical usage and vaporized hydrogen peroxide (VHP) decontamination.

METHODS

Three variables were assessed for effect on PFE following VHP decontamination: VHP sterilizer model, N95 respirator model, and prior N95 clinical usage.

FINDINGS

The VHP sterilizer model and N95 FFR model impacted PFE performance. Worn N95 FFRs had a 91% lower odds of exhibiting ≥95% PFE compared with the control.

CONCLUSION

This work highlights the importance of validating any N95 FFR decontamination programme in its entirety, including prior clinical usage.

Whole genome and transcriptome analysis enhances precision cancer treatment options

BACKGROUND

Recent advances are enabling delivery of precision genomic medicine to cancer clinics. While the majority of approaches profile panels of selected genes or hotspot regions, comprehensive data provided by whole genome and transcriptome sequencing and analysis (WGTA) presents an opportunity to align a much larger proportion of patients to therapies.

PATIENTS AND METHODS

Samples from 570 patients with advanced or metastatic cancer of diverse types enrolled in the Personalized OncoGenomics (POG) program underwent WGTA. DNA-based data, including mutations, copy number, and mutation signatures, were combined with RNA-based data, including gene expression and fusions, to generate comprehensive WGTA profiles. A multidisciplinary molecular tumour board used WGTA profiles to identify and prioritize clinically actionable alterations and inform therapy. Patient responses to WGTA-informed therapies were collected.

RESULTS

Clinically actionable targets were identified for 83% of patients, 37% of whom received WGTA-informed treatments. RNA expression data were particularly informative, contributing to 67% of WGTA-informed treatments; 25% of treatments were informed by RNA expression alone. Of a total 248 WGTA-informed treatments, 46% resulted in clinical benefit. RNA expression data were comparable to DNA-based mutation and copy number data in aligning to clinically beneficial treatments. Genome signatures also guided therapeutics including platinum, PARP inhibitors, and immunotherapies. Patients accessed WGTA-informed treatments through clinical trials (19%), off-label use (35%), and as standard therapies (46%) including those which would not otherwise have been the next choice of therapy, demonstrating the utility of genomic information to direct use of chemotherapies as well as targeted therapies.

CONCLUSIONS

Integrating RNA expression and genome data illuminated treatment options that resulted in 46% of treated patients experiencing positive clinical benefit, supporting the use of comprehensive WGTA profiling in clinical cancer care.

CLINICAL TRIAL NUMBER

NCT02155621.

Novel biomarkers predict ablation outcomes in long stranding persistent atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NIHR

Background

Ablation of long-standing persistent atrial fibrillation (LSPAF) is not always successful. The arrhythmia burden was reduced by 75% by 12 months in majority (72%) of patients with LSPAF who underwent surgical or percutaneous ablation in the CASA-AF trial. We hypothesised that biomarker(s) improve prediction of clinical success and offer insights into mechanisms.

Objective

To identify biomarkers that predict success (75% arrhythmia burden reduction) after ablation for LSPAF at 12-months.

Methods

Amongst patients participating in the CASA-AF RCT (ISRCTN18250790), pre-ablation serum samples were selected for 20 patients who met criteria for ablation-success at 12 months, and 20 who did not. Olink ProteomicsTM (Sweden) provided analyses using three biomarker panels [inflammation (INFL), cardiovascular III (CVD III), and cell cytology (CELL)] each containing 92 biomarkers. Univariate and multivariable analyses were adjusted for age, sex, BMI, LA diameter and CRP. ROC analysis was undertaken to assess the diagnostic accuracy of the biomarkers. To counter the false discovery rate, Benjamini-Hochberg correction was utilised.

Results

When patients with ablation-success and -failure were compared, no differences in demographics or cardiac function were found. On univariate analysis, several biomarkers in each panel were associated with ablation-success. Multivariable analysis narrowed the range of biomarkers and identified those that were jointly predictive of outcome: INFL (MCP1 + CD8A + CD40, Figure 1), CVD III (FAS + CPB1) and CELL (GCG + ENTPD6 + IL17RB). These joint biomarkers were analysed using ROC (Figure 2), which showed that increases of biomarkers on the INFL panel (MCP1 + CD8A + CD40) were associated with a greater risk of failure and achieved the highest AUC for prediction of outcome [0.82 (0.75-0.87)].

Conclusion

The increase in the serum concentration of markers of inflammation (MCP1 + CD8A + CD40) might be used to identify patients less likely to have sustained benefit from LSPAF ablation. Further studies are required to confirm their prognostic value as pre-procedural biomarkers.

Conduction system pacing in the adult congenital population; feasibility and outcomes

Funding Acknowledgements

Type of funding sources: None.

Background

Left bundle pacing (LBP) is an evolving pacing method designed to capture the intrinsic conduction and minimise ventricular dys- synchrony. Anatomical complexity, scars of previous corrective surgeries and haemodynamic properties of adult congenital heart disease (ACHD) population could increase challenges of LBP. We describe our experience in LBP in ACHD patients and different patient groups.

Purpose

To compare the feasibility of LBP in ACHD patient population and non-ACHD patients.

Methods

We included all patients who had LBP at our institution in 2020 and 2021. Demographic data, imaging data, procedural parameters and follow up data were collected and analysed.

Results

A total of 36 patients were included and divided into two groups: ACHD (n=8, mean age, 54 years, 38% females) and non-ACHD (n=28, mean age, 74 years, 43% females). ACHD anatomy included simple lesions (4) as atrial and ventricular septal defects, partial anomalous pulmonary venous drainage, bicuspid aortic valve and Shone’s syndrome, moderate (3), as Tetralogy of Fallot with surgical repair, and complex (1), as transposition of great arteries with Mustard repair. Non-ACHD included patients with structurally normal heart, dilated cardiomyopathy, and those who underwent mitral and aortic valve interventions. Mean left ventricular ejection fraction in ACHD group was 59.5%, and 57.5% in non-ACHD. Late gadolinium enhancement in basal septal area was present in 5 patients in ACHD group. Acute success rate, defined as capture of left bundle branch, was 100% in ACHD group, and 88% in non-ACHD. No acute complications were recorded in both groups. Mean pre-procedural QRS duration was longer in ACHD group (170 ms, vs, 120, p=<0.001). Mean reduction in QRS duration in ACHD group was 27 ms, vs, 15, p= 0.856. Mean procedural and fluoroscopy times were similar in both groups (ACHD, 75.5 minutes, vs, 70, p= 0.26, and ACHD, 9 minutes, vs 7.13, respectively, p= 0.46). Pacing parameters at implantation and after 2 months were satisfactory in both groups (Fig 1).

Conclusion

Left bundle pacing is feasible in ACHD population as compared to non-ACHD patients, with low incidence of complications. Procedural and fluoroscopic times were similar in both groups. Pacing parameters were satisfactory and stable over 2 month-follow up.

The acute haemodynamic response with endocardial biventricular pacing: comparing RV paced and LBBB patients

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Boston Scientific

Background

A third of patients that receive cardiac resynchronisation (CRT) are non-responders. Predictors of positive response include broader QRS duration, non-ischaemic aetiology and sinus rhythm, but it is still unclear whether lead placement site determines a positive responder.

Purpose

We assessed the acute haemodynamic response of endocardial biventricular pacing in patients with intrinsic left bundle brunch block (LBBB) versus LBBB due to pre-existing right ventricular pacing (RVP).

Methods

Patients who fulfilled standard criteria for CRT implantation but had failed conventional (coronary sinus) left ventricular (LV) lead placement (primary or revision) or were deemed clinical ‘non-responders after > 6 months of conventional CRT were enrolled. The acute haemodynamic response during endocardial biventricular pacing was assessed with a roving LV lead at 9 different locations (basal and mid: septal, anterior, posterior and lateral walls and apex). Acute changes in beat-to-beat systolic blood pressure (SBP) in the left ventricle were recorded and analysed.

Results

We recruited 23 patients across 10 UK centres: 14 intrinsic LBBB and 9 dependent on RVP. Patient characteristics were comparable: age (mean 67 + 10.6 years vs. 62 + 15.4 years), ischaemic (63% vs 50%), QRS (160 + 18ms vs. 190 + 36ms, p =0.07). Of the RVP group 5/9 had septal RV leads (the remainder apically positioned).

There was no difference in the SBP improvement between the groups: change in SBP ranged from -5.25 – 19.91mmHg (median 3mmHg) in RVP patients vs -5.92 – 23.03mmHg (median 3mmHg) for intrinsic LBBB. However, the improvement in SBP was more consistent across the different segments in the patients with RVP (group A), as compared to intrinsic LBBB (group B), where the lateral wall and then non-septal walls provided the greatest haemodynamic improvement.

Figure 1: depicts SBP improvement (in mmHg) during endocardial biventricular pacing in different positions within the LV for patients with RVP (A) vs underlying intrinsic LBBB (B): 9 segment model of the LV: Ant (anterior wall), Lat (lateral wall), Post (posterior wall), Sept (septum). Outer ring represents the four basal LV locations, middle ring the mid LV locations and centre ring the apex. Scale depicts mmHg improvement in SBP.

Conclusion

When implanting an LV lead for patients who are RV pacing dependent any position within the LV provides an acute haemodynamic improvement, compared with those with intrinsic LBBB, where a targeted lateral wall approach is more important. This finding corroborates the key differences in LV activation patterns for induced versus intrinsic LBBB.

The ins and outs of male breast and anterior chest wall lesions from childhood to adulthood

Physiological and pathological processes arising from the breast and anterior chest wall may share similar clinical presentations because of the small volume of male breasts. Therefore, imaging is frequently required to localise and characterise the lesion and guide biopsy when radiological findings are equivocal or suspicious. Mammography or digital breast tomosynthesis (DBT) and ultrasound are the mainstays of breast imaging work-up. Other imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) and positron-emission tomography (PET) can sometimes augment the investigation and aid treatment planning. This article reviews the key imaging features of a wide spectrum of benign and malignant conditions that involve the male breast and anterior chest wall across various age groups. Familiarisation with the salient radiological findings is essential for reaching an accurate diagnosis and optimising management.

The impact of travel distance to treatment centre on oral tongue squamous cell carcinoma survival and recurrence

There have been no prior studies examining the effect of distance to the treatment centre on oral squamous cell carcinoma outcomes in Australia. The purpose of this study was to analyse the impact of travel distance on oral tongue squamous cell carcinoma (OTSCC) outcomes. This was a retrospective analysis of 243 patients who received surgical treatment ± adjuvant therapy between 2007 and 2016. The overall survival (OS), disease-specific survival (DSS), and freedom from loco-regional failure (FFLRF) survival analyses were conducted using Kaplan-Meier curves and a multivariate Cox proportional hazards model. A competing risk (CR) analysis was conducted. Patients living ≥200 km from the treatment centre, when compared with those living within 40 km, had worse OS (hazard ratio (HR) 3.11, 95% confidence interval (CI) 1.74-5.54), DSS (HR 2.58, 95% CI 1.30-5.12), and FFLRF (HR 2.47, 95% CI 1.22-5.01). These discrepancies were significant when adjusted for socioeconomic status (OS P < 0.001, DSS P  0.004, FFLRF P = 0.005) and in the presence of CR (OTSCC-specific death with CR 'non-disease-related death' P =0.030, FFLRF with CR 'any cause death' P = 0.013, FFLRF with CR 'OTSCC-specific death' P = 0.004). Patients with OTSCC living ≥200 km from the treatment centre were found to have worse outcomes than those living within 40 km.

Assessing Lung Parenchymal Enhancement on Dual-Energy CT Pulmonary Angiograms: Potential utility of dual-energy technique as an angiographic and parenchymal 'one-stop shop' in the initial workup of patients with pulmonary symptoms

OBJECTIVE

The aim of this study was to assess the enhancement of lung parenchyma on dual-energy (DE) computed tomogram (CT) by comparing attenuation between routine post-contrast and dual-energy generated virtual unenhanced (VU) images.

METHODS

Patients presenting to the Emergency Department who subsequently underwent DE-CT pulmonary angiogram from the 1st to the 30th of November were enrolled. The DE data set obtained was used to generate VU images. Attenuation in Hounsfield units (HU) was measured at two sites for each patient and compared between VU and routine post-contrast (PC) reconstructions. Statistical analysis was performed using paired-samples t-test.

RESULTS

There is a statistical difference between lung parenchymal attenuation value between the CV and PC images, denser in the PC dataset and also towards the bases, with a mean HU of -841 and -817 (difference of 24) respectively.

CONCLUSIONS

This study confirms increased lung parenchymal density when comparing PC and VU reconstructions. Based on results, the paper recommends utilising dual-energy capabilities for VU reconstructions in CTPAs to optimise assessment of lung parenchyma.

What is a prevention visit? A qualitative study of a structured approach to prevention and screening - the BETTER WISE project

BACKGROUND

This qualitative study is a sub-component of BETTER WISE, a comprehensive and structured approach that proactively addresses chronic disease prevention, screening, and cancer survivorship, including screening for poverty and addressing lifestyle risks for patients aged 40 to 65. Patients (n = 527) from 13 primary care clinics (urban, rural, and remote) in Alberta, Ontario, and Newfoundland & Labrador, Canada agreed to participate in the study and were invited to a one-hour prevention visit delivered by a Prevention Practitioner (PP) as part of BETTER WISE. We identified the key components of a BETTER WISE prevention visit based on patients' and primary care providers' perspectives.

METHODS

Primary care providers (PPs, physicians and their staff) participated in 14 focus groups and 19 key informant interviews to share their perspectives on the BETTER WISE project. Of 527 patients who agreed to participate in the study and were invited for a BETTER WISE prevention visit with a PP, we received 356 patient feedback forms. We also collected field notes and memos and employed thematic analysis using a constant comparative method focusing on the BETTER WISE prevention visit.

RESULTS

We identified four key themes related to a BETTER WISE prevention visit: 1) Creating a safe environment and building trust with patients: PPs provided sufficient time and a safe space for patients to share what was important to them, including their concerns related to poverty, alcohol consumption, and mental health, topics that were often not shared with physicians; 2) Providing personalized health education: PPs used the BETTER WISE tools to provide patients with a personalized overview of their health status and eligible screening; 3) Non-judgmental empowering of patients: Instead of directing patients on what to do, PPs evoked patients' preferences and helped them to set goals (if desired); and 4) Integrating care for patients: PPs clarified information from patients' charts and surveys with physicians and helped patients to navigate resources within and outside of the primary care team.

CONCLUSIONS

The results of this study underscore the importance of personalized, trusting, non-judgmental, and integrated relationships between primary care providers and patients to effectively address chronic disease prevention, screening, and cancer survivorship as demonstrated by the BETTER WISE prevention visits.

TRIAL REGISTRATION

This qualitative study is a sub-component of the BETTER WISE pragmatic, cRCT, trial registration ISRCTN21333761 (date of registration 19/12/2016).

Safety and acute clinical outcomes of atrial fibrillation catheter ablation in octogenarians: a multicentre evaluation with a matched younger cohort

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Sven Knecht and the International Octogenarian AF ablation group

Background

Octogenarians are a fast-growing demographic with a high burden of atrial fibrillation (AF). There are limited data on procedural safety and acute outcomes of catheter ablation (CA) for AF in this group.

Purpose

Investigation of complications & outcomes in octogenarians undergoing CA for AF.

Methods

Data on all octogenarian patients who underwent AF ablation at nine European cardiology centres between 2013 and 2019 were retrospectively analysed and matched with control patients aged &lt;80 years.  The characteristics used for matching were type of AF, type of procedure (de novo or redo), & the year of procedure.

Results

216 octogenarians (81.9 ± 1.9 years; 52.8% females) underwent an AF ablation procedure, and were matched with 216 patients aged &lt;80 years (62.4 ± 9.5 years, 34.7% females), p &lt;0.001 for both. The proportion of paroxysmal and persistent AF was 43.5% & 56.5% respectively in both groups, and 79.3% of the procedures were de novo. RF ablation made up 75.4% & 75.9% (p = 0.90) procedures in octogenarians and controls respectively.  17 complications occurred in 14 (7.9%) octogenarian patients and 11 in 11 (5.1%) patients in the younger matched cohort (p = 0.07). There were 4.2% & 1.9% major complications (p= 0.17) and 3.7% & 3.2% minor complications (p= 0.77) in the octogenarian & younger cohorts respectively. Complications in octogenarians consisted of groin complications (n = 6), pneumonia (n = 3), pericardial effusion (n = 2), phrenic nerve injury (n = 2), pulmonary oedema (n = 1), gastroparesis (n = 1), stroke (n = 1). Acute procedural success rates were 99.1% & 99.5% (p = 0.62) The complication rates were similar for RF; 6.0% vs 5.4% (p = 0.79) and Cryoballoon; 14.0% vs 4.1% (p = 0.09) in both octogenarians and younger cohort respectively.

Conclusion

In spite of significantly higher overall risk profile of octogenarians undergoing AF ablation, there is no difference in acute procedural success and complication rates as compared to younger patients Catheter ablation of AF in octogenerians Octogenarians n = 216 Matched Controls (aged &lt; 80yrs) n = 216 P value Age (yrs), mean (SD)s 81.9 (1.9) 62.4(9.5) &lt; 0.0001 Females, (%) 52.8 34.7 0.0002 CHA2DS2-VASc, mean (SD) 3.6 (1.2) 1.4 (1.3) &lt; 0.0001 Mean LA size, mm 42.8 ± 8.3mm 45.8 ± 16.2 0.062 Impaired LV function, (%) 23.7 17.9 0.206 IHD, (%) 20.7 5.9 &lt; 0.0001 Procedural time (mins), mean (sd) 150.6 (69.7) 148.9 (64.4) 0.914 All complications, n (%) 17 (7.9) 11 (5.1) 0.073

Development of Gross Motor Evaluation for Children Aged 18 to 42 Months

PURPOSE

To test the reliability and validity of the gross motor items making up a new instrument, Hong Kong Comprehensive Assessment Scales for Toddlers (HKCAS-T) for quantifying gross motor development among children aged 18 to 42 months.

METHODS

The 37 items were administered to 330 children, including 258 typically developing children and 72 children with gross motor delay.

RESULTS

Rasch analyzes indicated that the fit statistics of the 37 items were within the acceptable range. The assessment was found able to differentiate between typically developing children and those with gross motor delay and among children of different ages. The raw score reliability (KR-20) was 0.94.

CONCLUSION

The new instrument is a promising alternative for assessing young children's gross motor development.

Safety and efficacy of magnetic seed localisation of non-palpable breast lesions: pilot study in a Chinese population

INTRODUCTION

A magnetic seed marker system (Magseed, Endomagnetics, Cambridge, United Kingdom) is used as a localisation method for non-palpable breast lesions in the United States, Europe, and Hong Kong. It overcomes many limitations of conventional techniques and allows scheduling flexibility. We sought to evaluate its efficacy and safety in the Chinese population.

METHODS

We retrospectively reviewed all Chinese women who underwent magnetic seed marker-guided breast lesion excision from June 2019 to February 2020 at a single institution. Placement success (final target-to-seed distance <10 mm) was evaluated by imaging on the day of surgery. Specimen radiographs and pathology reports were reviewed for magnetic seed markers and target removal. Margin clearance and re-excision rates were analysed.

RESULTS

Twenty two magnetic seed markers were placed in 21 patients under sonographic or stereotactic guidance to localise 21 target lesions. One target lesion required two magnetic seed markers for bracketing. There was no migration of nine markers placed 6 to 56 days before the day of surgery. Placement success was achieved in 20 (90.9%) cases. Mean final target-to-seed distance was 3.1 mm. Two out of 21 (9.5%) lesions required alternative localisation due to marker migration ≥10 mm, while 19 (90.5%) lesions underwent successful magnetic seed marker-guided excision. Three of these 19 lesions (15.8%) were excised with therapeutic intent, one of which (33%) required re-excision due to a close margin. All 22 magnetic seed markers were successfully removed. No complications were reported.

CONCLUSION

Magnetic seed markers demonstrated safety and efficacy in Chinese women for breast lesion localisation and excision.

Multiplex real-time PCR assays for the prediction of cephalosporin, ciprofloxacin and azithromycin antimicrobial susceptibility of positive Neisseria gonorrhoeae nucleic acid amplification test samples

BACKGROUND

The incidence of antimicrobial-resistant Neisseria gonorrhoeae (GC) is rising in Canada; however, antimicrobial resistance (AMR) surveillance data are unavailable for infections diagnosed directly from clinical specimens by nucleic acid amplification tests (NAATs), representing over 80% of diagnoses. We developed a set of 10 improved molecular assays for surveillance of GC-AMR and prediction of susceptibilities in NAAT specimens.

METHODS

Multiplex real-time PCR (RT-PCR) assays were developed to detect SNPs associated with cephalosporin (ponA, porB, mtrR -35delA, penA A311V, penA A501, N513Y, G545S), ciprofloxacin (gyrA S91, parC D86/S87/S88) and azithromycin [23S (A2059G, C2611T), mtrR meningitidis-like promoter] resistance. The assays were validated on 127 gonococcal isolates, 51 non-gonococcal isolates and 50 NAATs with matched culture isolates. SNPs determined from the assay were compared with SNPs determined from in silico analysis of WGS data. MICs were determined for culture isolates using the agar dilution method.

RESULTS

SNP analysis of the 50 NAAT specimens had 96% agreement with the matched culture RT-PCR analysis. When compared with MICs, presence of penA A311V or penA A501 and two or more other SNPs correlated with decreased susceptibility and presence of three or more other SNPs correlated with intermediate susceptibility to cephalosporins; presence of any associated SNP correlated with ciprofloxacin or azithromycin resistance. NAAT-AMR predictions correlated with matched-culture cephalosporin, ciprofloxacin and azithromycin MICs at 94%, 100% and 98%, respectively.

CONCLUSIONS

We expanded molecular tests for N. gonorrhoeae AMR prediction by adding new loci and multiplexing reactions to improve surveillance where culture isolates are unavailable.

Evaluation of a new sink design incorporating ozonated water

BACKGROUND

Novel sink and U-trap designs have been developed to reduce contamination by users and diminish biofilm. Real-world experience with new sink designs and adjunctive measures such as ozone has been limited.

AIMS

To assess a new sink design for splashback and to evaluate the ozonated water feature for reduction of microbial bioburden.

METHODS

A portable sink unit was created that permitted the application of white absorbent paper to plexiglass shields beside and behind the sink. Participants, wearing painter coveralls and masks, spread 30 mL of tempera paint over their hands and washed for 20 s with neutral soap. Each participant repeated this five times sequentially, and cumulative results were recorded. Escherichia coli was exposed to ozonated water from the sink unit and to regular tap water and evaluated for microbial survival.

FINDINGS

Compared with a conventional sink, the SmartFLO3 sink had less environmental contamination within the sink, surrounding area and splashback on to the participant. Despite modifications to enhance ozone generation, readings of reactive oxygen species did not exceed 0.3 ppm, and no significant bactericidal effect was demonstrated.

CONCLUSIONS

The SmartFLO3 sink reduces splashback and has the potential to reduce pathogen transmission from sinks. At the low levels of ozone generated in this study, no clear bacterial killing effect was observed compared with tap water alone.

2400Early and late effects of cardiac resynchronization therapy in adult congenital heart disease

Background

There are limited data regarding cardiac resynchronization therapy (CRT) in adult congenital heart disease (ACHD).

Purpose

We aimed to assess early and late outcomes of CRT amongst patients with ACHD.

Methods

We retrospectively studied ACHD patients receiving CRT (2004–2017). Clinical and echocardiographic data were analyzed at baseline, early (1.8±0.8 years) and late (4.7±0.8 years) follow-up after CRT.

Results

Fifty-four ACHD patients (median age 46 years, range 18–73 years, 74% male) had CRT (biventricular paced >90%) and were followed for 5.7±3.0 years. Thirty-nine (72%) patients had a systemic left ventricle (LV). Underlying cardiac anatomy included left ventricular outflow tract lesions (n=17; 32%), tetralogy of Fallot (n=11; 20%), right ventricular outflow tract lesions (n=5; 9%), atrioventricular septal defects (n=5; 9%) and atrial septal defect with right aortic arch (n=1; 2%). Fifteen (28%) patients had a systemic right ventricle (RV): 13 (24%) with congenitally corrected transposition of great arteries, and 2 (4%) with transposition of the great arteries after Mustard repair.

Compared to baseline, CRT was associated with significant improvement at early follow-up in NYHA functional class, QRS duration, cardiothoracic ratio, left and right atrial volume index (P<0.05 for all) in the overall population; improvement in NYHA class was sustained at late follow-up. Amongst patients with a systemic LV, there was significant increase in LV ejection fraction and reduction in LV end-systolic volume at early and late follow up (P<0.05 for both). There is trend in improvement of RV fractional area change in the patients with a systemic RV but not met statistical significance (P=0.070). Findings were summarized in Figure 1.

Eleven patients died and 2 had heart transplantation unrelated to systemic ventricular morphology. Thirty-five (65%) patients responded positively to CRT but only baseline QRS duration was a predictor of the positive response.

Conclusion

CRT results in sustained improvement in functional class, systemic LV size and function. QRS duration but not QRS morphology was a predictor of the positive response seen at early follow-up in 2/3 of ACHD patients.

P5694Outcomes of patients with arrhythmogenic right ventricular cardiomyopathy after ventricular tachycardia ablation without an implantable cardioverter-defibrillator: a multicenter international study

Background

In arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), implantable cardioverter-defibrillators (ICD) after an episode of sustained monomorphic ventricular tachycardia (MVT) are currently recommended in most situations. However, radiofrequency catheter ablation (RCA) is effective in reducing recurrent VT and whether MVT is a surrogate of sudden cardiac death is debated when other risk factors are lacking.

Purpose

To report the outcomes of patients with ARVC/D who underwent RCA of well-tolerated MVT without a back-up ICD.

Methods

Patients with a definite ARVC/D diagnosis according to the 2010 Task Force revised criteria who underwent RCA of well-tolerated MVT at 9 tertiary centers across 5 countries, without an ICD prior to RCA and in the 3 following months were retrospectively included. Patients presenting with syncope or electrical storm, and patients with left ventricular ejection fraction <50% were excluded. Similar patients implanted with an ICD prior or without RCA in the same period served as controls.

Results

Sixty-five patients [median age 46.1 years, range (19.5–73.8), 75% males] underwent RCA of MVT between 2003 and 2016. Familial history of ARVC/D was found in 11% of patients. Epsilon-waves were present in 19% and T-waves inversion beyond V2 in 43%. A right ventricular (RV) ejection fraction ≤40% or fractional area change ≤33% was found in 14 (25%) patients. Median left ventricular ejection fraction was 61% (50–70). Clinical presentation was palpitations in 81% of patients and near-syncope in 14%. Prior to RCA, patients were on beta-blockers alone in 18%, class I drugs in 37% and amiodarone in 9%, while 15% of patients were free any antiarrhythmic medication. Only 1 patient (2%) had >1 clinical VT morphology. Median VT rate was 180 (110–270). An epicardial approach was used in 31% patients. The clinical VT was inducible in 84% of patients. The median number of targeted RV site was 1 (1–3) (RV outflow tract in 72%). Full acute success defined inability to induce any VT was achieved in 72% of patients. During a median follow-up time of 49 month (1.4–162), there was no death or aborted cardiac arrest. Survival without VT recurrence was estimated at 82%, 71% and 60%, 12-, 36- and 60-months after RCA. No VT recurrence was observed among patient who had undergone an epicardial ablation. Among patients with VT recurrence, 6 (35%) did not receive an ICD, and 14 (70%) underwent redo RCA. An ICD was implanted in 10 patients, including 5 for VT recurrence. Fifty-eight patients constituted the control group, and 64% had appropriate ICD interventions during follow-up.

Conclusions

Despite a significant rate of VT recurrence, selected patients with ARVC/D who underwent RCA for stable MVT without an ICD did not experience any arrhythmic death. Further prospective studies are mandatory to precise the respective places of ICD and RCA in the management of ARVC/D patients with well-tolerated MVT.

Acknowledgement/Funding

None

P4744Patients with atrial fibrillation exhibit a systemic prothrombotic state attributable to impaired endogenous fibrinolysis

Background

The association of atrial fibrillation (AF) with thromboembolic stroke due to stasis in the left atrium and left atrial appendage is well described. Whether AF is associated with a systemic prothrombotic state, detectable in peripheral blood, unclear. Previous studies have been inconsistent, with some very small previous studies (<30 patients each) variably indicating that patients with AF may have raised platelet reactivity and levels of antithrombin III, d-dimer, PAI-1 and t-PA-PAI complexes. These cumbersome laboratory tests of coagulation and fibrinolysis are not readily available in the clinical setting.

Purpose

It was our aim to compare, in peripheral venous blood, thrombotic and endogenous fibrinolytic profile of healthy volunteers and patients with newly diagnosed nonvalvular atrial fibrillation (NVAF), using a point-of-care technique.

Methods

In a prospective observational study, venous blood samples were taken from 98 healthy volunteers and 100 patients with newly diagnosed NVAF in the out-patient setting. Patients with newly diagnosed NVAF had venous blood tested before any treatment was initiated with aspirin or oral anticoagulation. Thrombotic status was assessed using the Global Thrombosis Test (GTT), a point-of-care test using native non-coagulated blood, assessed within 15 sec of blood withdrawal. The time to form an occlusive venous thrombus in native (non-citrated) blood, a measure of platelet reactivity (occlusion time, OT) and the time taken to spontaneous endogenous fibrinolysis to restore flow (lysis time, LT) were assessed.

Results

Basic blood tests (full blood count, renal and liver function, inflammatory markers) were normal in all subjects. The groups were matched for sex and race. Mean age of the healthy cohort was 34±8 years and patients 65±10 years.

Endogenous fibrinolysis was markedly impaired in patients with NVAF compared to healthy individuals as shown by markedly prolonged LT (median 2015s [interquartile range IQR 1555–2507] vs. 1124s [IQR 919–1554], p<0.ehz745.11201). There was no difference in platelet reactivity between patients and normal volunteers (369s [IQR 308–445]vs 368s [IQR 309–441], p=0.704). Sensitivity analysis was performed on a subgroup matched for age, sex and race. LT remained significantly longer in patients with NVAF compared to controls (1569s [IQR 1499–2244] vs. 1219s [IQR 943–1560], p=0.03), with no difference in platelet reactivity (p=NS).

Conclusion

In the largest study to date and using a clinically-friendly automated point-of-care technique, we show that patients with NVAF exhibit a systemic prothrombotic state, attributable to significantly impaired endogenous fibrinolysis compared with healthy volunteers. Further studies are needed to see if this could become a screening test for the prothrombotic state in patients with NVAF.

Acknowledgement/Funding

None

P2831Safety of atrial fibrillation catheter ablation in the elderly

Background

Catheter ablation for drug refractory, symptomatic atrial fibrillation (AF), is becoming increasingly common and can be beneficial in alleviating symptoms. However, in the elderly, there are concerns about the risks an invasive procedure poses, with limited published data available in those aged over 80 years.

Purpose

To determine the complication risk of AF catheter ablation in the elderly

Methods

Complications were identified from patient records in 3156 consecutive patients who underwent radiofrequency catheter ablation for AF, at a tertiary cardiology centre between 2013–2017. All cases were performed under general anesthesia.

Results

In this cohort of 3156 patients (mean age= 62.9±11.0 years, female = 29.9%), 90 (2.85%) (mean age= 66±10.0 years, female = 49.5%) complications were identified. In patients aged ≥80 years, complications occurred in 5 out of 99 patients (5.05%) (mean age= 82.6±1.2, female=100%), compared to 85 out of 3057 patients (2.78%) in those aged <80 years (mean age= 65±10.3, female = 49.4%). The difference was not significant p=0.18. Complications in the elderly all occurred acutely, and included groin haematoma (2.02%), pneumonia (2.02%) and pericardial effusion (1.01%).

Conclusion

Catheter ablation for AF in patients ≥80 years of age, is not associated with a significant increase in complication risk, compared to those who are younger.

P978Core to block: a new ablation strategy for treating persistent atrial fibrillation

Background

Ablation strategy targeting the core of atrial fibrillation (AF) rotors alone can lead to both stabilisation and destabilisation of rotational activity. Non-contact dipole density mapping system is designed to rapidly identify dynamic regional atrial activation patterns of interest (API) during AF.

Purpose

To assess the feasibility of an ablation strategy consisted of pulmonary vein isolation + targeting the core of APIs followed by linear ablation to the nearest non-conducting boundary to treat persistent AF.

Methods

The ablation strategy includes: 1. Antral pulmonary vein electrical isolation (APVI); 2. APIs (focal, localised rotational and localised irregular activation; Figure1) detection by dipole density mapping; 3. API core ablation followed by linear ablation to the nearest non-conduction barrier (APVI/mitral valve); 4. repeat step 2 and 3 in LA (RA, if necessary) until sinus rhythm is achieved.

Results

Consecutive 40 persistent AF patients (mean 62±12 years, 29 males, AF duration 10±4 months, LA diameter 42±9 mm) were included from 2 centres. An average of 2.0±0.7 APIs per patient were targeted post-APVI. Acute AF termination by ablation was achieved in 27/40 (68%) patients. The mean ablation time of APVI and “Core to block” was 33±12 mins and 31±22 mins, respectively. No major complication occurred. During a mean follow-up of 12±5 months, 32/40 patients (80%) maintained sinus rhythm.

Conclusion

APVI + “Core to block” guided by the dipole density mapping is feasible for treating persistent AF. A larger randomised study is needed to test the effectiveness of this ablation strategy.

Acknowledgement/Funding

None

2401Cardiac resinchronization therapy for the systemic right ventricle: a single center experience

Introduction

Cardiac resynchronization therapy (CRT) has become a treatment of choice in patients with chronic heart failure (HF). About 25% of patients with systemic right ventricle (SRV) progress to symptomatic HF, which may be refractory to drug therapy and is commonly associated with significant morbidity and mortality. For these reasons, CRT has been emerging as an effective treatment strategy for patients with SRV failure and electrocardiographic signs of ventricular dyssynchrony. Few studies have reported the acute and long - term effects of CRT in SRV subjects, with different findings. Our study aimed to describe the experience with CRT in SRV patients in a single tertiary centre.

Purpose

Assess the long term efficacy of CRT in patient with SRV

Materials and methods

All consecutive SRV patients who underwent CRT implantation and/or upgrading between 1994 and 2018 at our tertiary centre were included. Clinical and echocardiographic parameters before and after CRT implantation were collected and analyzed.

Results

A total of 21 patients (mean age 47.8±14.8 years, 13 M) were implanted with CRT-P (12, 57%) or CRT-D (9,43%) during the study period. 90% of patients showed an anatomy of congenitally corrected transposition of the great arteries (CCTGA), whereas 9.5% underwent Mustard procedure for transposition of the great arteries (TGA). Among CCTGAs, 11 (52.5%) subjects underwent previous surgical procedures, including implant of a conduit between the left ventricle (LV) and the pulmonary artery (PA) in 8 (38%) patients, tricuspid valve repair in 2 (9.5%) and surgical closure of atrial septal defect in 1 (5%). Before CRT implant/upgrading, 10 (48%) patients had a moderate to severe reduction in the SRV ejection fraction (EF) and 7 (33%) had a moderate to severe tricuspid regurgitation (TR). Overall, 15 (71%) patients referred a NYHA II or III. After a median follow up of 57 months (IQR 35–83), 43% of patients showed an improvement in their functional status, which was associated with an improvement of SRV EF and TR only in 22% and 33% of these patients. On the contrary, no patient reported a worsening in NYHA class, while SRV EF decreased in 28.5% and the grade of TR worsen in 23.8% of patients.

Conclusions

CRT is emerging as an effective treatment for SRV dysfunction. However, criteria for implantation are not well defined and the deterioration of SRV function related to subpulmonary univentricular pacing should be considered. Moreover, TR did not improve in this study, suggesting that concurrent tricuspid valve interventions may be necessary in patients with severe TR and may facilitate the improvement in RV function achieved with CRT. Proper planning, tertiary expertise and international collaborations are all paramount in this field.

P3756Diverse activation patterns during persistent atrial fibrillation characterised by dipole density non-contact mapping

Background

Global simultaneous recording of activation during atrial fibrillation (AF) can elucidate underlying mechanisms contributing to AF maintenance. A better understanding of these mechanisms may allow for a personalised ablation strategy to treat persistent AF.

Purpose

To characterise left atrial endocardial activation patterns during AF using a novel non-contact dipole density mapping.

Methods

Activation patterns were characterised into three sub-types: (i) focal with centrifugal activation (FCA); (ii) localised rotational activation (LRA); (iii) localised irregular activation (LIA). Continuous activation patterns were quantified and distributed in the left atrium.

Results

A total of 144 persistent AF segments with 1068 activation patterns from 25 patients were analysed. The most common pattern was LIA (63%), which consist of four disparate features: slow conduction (45%), pivoting (30%), collision (16%) and acceleration (7%). LRA was the second commonest pattern (20%). FCA (17%) arose frequently from the PVs/ostia. Continuous AF activations comprise multiple combinations of FCA, LRA and LIA, transitioning from one to the next without a discernible order. Preferential conduction areas were typically seen in mid-anterior (48%) and lower-posterior (40%) walls where dominant activations were made up of LRA and LIA.

Conclusion

AF is characterised by heterogenous activation patterns that vary between individuals. Clinical implications of individualised ablation strategies guided by dipole density mapping will have to be determined.

Acknowledgement/Funding

None

Efficacy and safety of 20% albumin fluid loading in healthy subjects: a comparison of four resuscitation fluids

Recently, buffered salt solutions and 20% albumin (small volume resuscitation) have been advocated as an alternative fluid for intravenous resuscitation. The relative comparative efficacy and potential adverse effects of these solutions have not been evaluated. In a randomized, double blind, cross-over study of six healthy male subjects we compared the pulmonary and hemodynamic effects of intravenous administration of 30 ml/kg of 0.9% saline, Hartmann's solution and 4% albumin, and 6 ml/kg of 20% albumin (albumin dose equivalent). Lung tests (spirometry, ultrasound, impulse oscillometry, diffusion capacity, and plethysmography), two- to three-dimensional Doppler echocardiography, carotid applanation tonometry, blood gases, serum/urine markers of endothelial, and kidney injury were measured before and after each fluid bolus. Data were analyzed with repeated measures ANOVA with effect of fluid type examined as an interaction. Crystalloids caused lung edema [increase in ultrasound B line ( P = 0.006) and airway resistance ( P = 0.009)], but evidence of lung injury [increased angiopoietin-2 ( P = 0.019)] and glycocalyx injury [increased syndecan ( P = 0.026)] was only observed with 0.9% saline. The colloids caused greater left atrial stretch, decrease in lung volumes, and increase in diffusion capacity than the crystalloids, but without pulmonary edema. Stroke work increased proportionally to increase in preload with all four fluids ( R2 = 0.71). There was a greater increase in cardiac output and stroke volume after colloid administration, associated with a reduction in afterload. Hartmann’s solution did not significantly alter ventricular performance. Markers of kidney injury were not affected by any of the fluids administrated. Bolus administration of 20% albumin is both effective and safe in healthy subjects.

NEW & NOTEWORTHY Bolus administration of 20% albumin is both effective and safe in healthy subjects when compared with other commonly available crystalloids and colloidal solution.