Temporal evolution of chest radiographic appearances in COVID-19 with clinicoradiological associations: a multicentre United Kingdom resident-led study

AIM

To describe the (a) frequency of improving, static, and worsening chest radiograph (CXR) appearances; (b) differences in demographic, initial rudimentary haematological and CXR variables and these patterns; and (c) frequency of different trajectories of serial CXR evolution, in COVID-19 patients presenting consecutively.

MATERIALS AND METHODS

This multicentre retrospective study included all COVID-19 patients admitted from 1-30 April 2020, meeting the inclusion criteria across 24 (blinded) hospitals. Follow-up CXRs on admission, the subsequent (where available), and at 4-8 weeks were scored for the presence of parenchymal opacities across six zones. Three cohorts were defined: improved, static, and/or worsened. The chi-squared and Kruskal-Wallis tests were used to compare demographic, laboratory, and CXR variables. Trajectories of CXR evolution were assessed when all three CXRs were available (226 patients).

RESULTS

Of 452 included patients (median age 66 years, interquartile range 54.3-79, 262 men), 211 (46.7%) improved, 140 (31%) were static, and 101 (22.3%) worsened. Improving patients were more likely younger, with a classic COVID-19 radiograph and higher initial CXR zonal severity scores (both p<0.001), while worsening patients had lower initial lymphocyte counts (p=0.008). The most frequent trajectory was worsened then improved (n=63, 27.9%) followed by static then improved (n=46, 20.4%) and static (n=42, 18.6%).

CONCLUSION

Most patients with COVID-19 during the first wave of the pandemic demonstrated radiographic improvement; these patients were more likely younger with classic COVID-19 appearances and initially more extensive abnormality. Conversely, radiographic deterioration was associated with lower lymphocyte counts. The three most common trajectories were worsening then improvement, static then improvement, and static throughout.

COVID-19 Stroke Apical Lung Examination Study 2: a national prospective CTA biomarker study of the lung apices, in patients presenting with suspected acute stroke (COVID SALES 2)

BACKGROUND

Apical ground-glass opacification (GGO) identified on CT angiography (CTA) performed for suspected acute stroke was developed in 2020 as a coronavirus-disease-2019 (COVID-19) diagnostic and prognostic biomarker in a retrospective study during the first wave of COVID-19.

OBJECTIVE

To prospectively validate whether GGO on CTA performed for suspected acute stroke is a reliable COVID-19 diagnostic and prognostic biomarker and whether it is reliable for COVID-19 vaccinated patients.

METHODS

In this prospective, pragmatic, national, multi-center validation study performed at 13 sites, we captured study data consecutively in patients undergoing CTA for suspected acute stroke from January-March 2021. Demographic and clinical features associated with stroke and COVID-19 were incorporated. The primary outcome was the likelihood of reverse-transcriptase-polymerase-chain-reaction swab-test-confirmed COVID-19 using the GGO biomarker. Secondary outcomes investigated were functional status at discharge and survival analyses at 30 and 90 days. Univariate and multivariable statistical analyses were employed.

RESULTS

CTAs from 1,111 patients were analyzed, with apical GGO identified in 8.5 % during a period of high COVID-19 prevalence. GGO showed good inter-rater reliability (Fleiss κ = 0.77); and high COVID-19 specificity (93.7 %, 91.8-95.2) and negative predictive value (NPV; 97.8 %, 96.5-98.6). In subgroup analysis of vaccinated patients, GGO remained a good diagnostic biomarker (specificity 93.1 %, 89.8-95.5; NPV 99.7 %, 98.3-100.0). Patients with COVID-19 were more likely to have higher stroke score (NIHSS (mean +/- SD) 6.9 +/- 6.9, COVID-19 negative, 9.7 +/- 9.0, COVID-19 positive; p = 0.01), carotid occlusions (6.2 % negative, 14.9 % positive; p = 0.02), and larger infarcts on presentation CT (ASPECTS 9.4 +/- 1.5, COVID-19 negative, 8.6 +/- 2.4, COVID-19 positive; p = 0.00). After multivariable logistic regression, GGO (odds ratio 15.7, 6.2-40.1), myalgia (8.9, 2.1-38.2) and higher core body temperature (1.9, 1.1-3.2) were independent COVID-19 predictors. GGO was associated with worse functional outcome on discharge and worse survival after univariate analysis. However, after adjustment for factors including stroke severity, GGO was not independently predictive of functional outcome or mortality.

CONCLUSION

Apical GGO on CTA performed for patients with suspected acute stroke is a reliable diagnostic biomarker for COVID-19, which in combination with clinical features may be useful in COVID-19 triage.

Large-scale validation study of an improved semiautonomous urine cytology assessment tool: AutoParis-X

BACKGROUND

Adopting a computational approach for the assessment of urine cytology specimens has the potential to improve the efficiency, accuracy, and reliability of bladder cancer screening, which has heretofore relied on semisubjective manual assessment methods. As rigorous, quantitative criteria and guidelines have been introduced for improving screening practices (e.g., The Paris System for Reporting Urinary Cytology), algorithms to emulate semiautonomous diagnostic decision-making have lagged behind, in part because of the complex and nuanced nature of urine cytology reporting.

METHODS

In this study, the authors report on the development and large-scale validation of a deep-learning tool, AutoParis-X, which can facilitate rapid, semiautonomous examination of urine cytology specimens.

RESULTS

The results of this large-scale, retrospective validation study indicate that AutoParis-X can accurately determine urothelial cell atypia and aggregate a wide variety of cell-related and cluster-related information across a slide to yield an atypia burden score, which correlates closely with overall specimen atypia and is predictive of Paris system diagnostic categories. Importantly, this approach accounts for challenges associated with the assessment of overlapping cell cluster borders, which improve the ability to predict specimen atypia and accurately estimate the nuclear-to-cytoplasm ratio for cells in these clusters.

CONCLUSIONS

The authors developed a publicly available, open-source, interactive web application that features a simple, easy-to-use display for examining urine cytology whole-slide images and determining the level of atypia in specific cells, flagging the most abnormal cells for pathologist review. The accuracy of AutoParis-X (and other semiautomated digital pathology systems) indicates that these technologies are approaching clinical readiness and necessitates full evaluation of these algorithms in head-to-head clinical trials.

Examining longitudinal markers of bladder cancer recurrence through a semiautonomous machine learning system for quantifying specimen atypia from urine cytology

BACKGROUND

Urine cytology is generally considered the primary approach for screening for recurrence of bladder cancer. However, it is currently unclear how best to use cytological examinations for assessment and early detection of recurrence, beyond identifying a positive finding that requires more invasive methods to confirm recurrence and decide on therapeutic options. Because screening programs are frequent, and can be burdensome, finding quantitative means to reduce this burden for patients, cytopathologists, and urologists is an important endeavor and can improve both the efficiency and reliability of findings. Additionally, identifying ways to risk-stratify patients is crucial for improving quality of life while reducing the risk of future recurrence or progression of the cancer.

METHODS

In this study, a computational machine learning tool, AutoParis-X, was leveraged to extract imaging features from urine cytology examinations longitudinally to study the predictive potential of urine cytology for assessing recurrence risk. This study examined how the significance of imaging predictors changes over time before and after surgery to determine which predictors and time periods are most relevant for assessing recurrence risk.

RESULTS

Results indicate that imaging predictors extracted using AutoParis-X can predict recurrence as well or better than traditional cytological/histological assessments alone and that the predictiveness of these features is variable across time, with key differences in overall specimen atypia identified immediately before tumor recurrence.

CONCLUSIONS

Further research will clarify how computational methods can be effectively used in high-volume screening programs to improve recurrence detection and complement traditional modes of assessment.

Artificial intelligence in radiology: trainees want more

AIM

To understand the attitudes of UK radiology trainees towards artificial intelligence (AI) in Radiology, in particular, assessing the demand for AI education.

MATERIALS AND METHODS

A survey, which ran over a period of 2 months, was created using the Google Forms platform and distributed via email to all UK training programmes.

RESULTS

The survey was completed by 149 trainee radiologists with at least one response from all UK training programmes. Of the responses, 83.7% were interested in AI use in radiology but 71.4% had no experience of working with AI and 79.9% would like to be involved in AI-based projects. Almost all (98.7%) felt that AI should be taught during their training, yet only one respondent stated that their training programme had implemented AI teaching. Respondents indicated that basic understanding, implementation, and critical appraisal of AI software should be prioritized in teaching. Of the trainees, 74.2% agreed that AI would enhance the job of diagnostic radiologists over the next 20 years. The main concerns raised were information technology/implementation and ethical/regulatory issues.

CONCLUSION

Despite the current limited availability of AI-based activities and teaching within UK training programmes, UK trainees' attitudes towards AI are mostly positive with many showing interest in being involved with AI-based projects, activities, and teaching.

Machine-learning algorithm in acute stroke: real-world experience

AIM

To assess the clinical performance of a commercially available machine learning (ML) algorithm in acute stroke.

MATERIALS AND METHODS

CT and CT angiography (CTA) studies of 104 consecutive patients (43 females, age range 19-93, median age 62) performed for suspected acute stroke at a single tertiary institution with real-time ML software analysis (RAPID™ ASPECTS and CTA) were included. Studies were retrospectively reviewed independently by two neuroradiologists in a blinded manner.

RESULTS

The cohort included 24 acute infarcts and 16 large vessel occlusions (LVO). RAPID™ ASPECTS interpretation demonstrated high sensitivity (87.5%) and NPV (87.5%) but very poor specificity (30.9%) and PPV (30.9%) for detection of acute ischaemic parenchymal changes. There was a high percentage of false positives (51.1%). In cases of proven LVO, RAPID™ ASPECTS showed good correlation with neuroradiologists' blinded independent interpretation, Pearson correlation coefficient = 0.96 (both readers), 0.63 (RAPID™ vs reader 1), 0.69 (RAPID™ vs reader 2). RAPID™ CTA interpretation demonstrated high sensitivity (92.3%), specificity (85.3%), and negative predictive (NPV) (98.5%) with moderate positive predictive value (PPV) (52.2%) for detection of LVO (N=13). False positives accounted for 12.5% of cases, of which 27.3% were attributed to arterial stenosis.

CONCLUSION

RAPID™ CTA was robust and reliable in detection of LVO. Although demonstrating high sensitivity and NPV, RAPID™ ASPECTS interpretation was associated with a high number of false positives, which decreased clinicians' confidence in the algorithm. However, in cases of proven LVO, RAPID™ ASPECTS performed well and had good correlation with neuroradiologists' blinded interpretation.

Positron emission tomography/computed tomography perfusion imaging with myocardial blood flow has diagnostic and prognostic value for cardiac allograft vasculopathy

Background

Cardiac allograft vasculopathy (CAV) is a leading cause of morbidity and mortality in patients with orthotopic heart transplantation (OHT). Invasive coronary angiography is the traditional method of screening for and diagnosing CAV. Alternative non-invasive modalities have been sought to screen for CAV. A small, single-center study utilizing Positron Emission Tomography/Computed Tomography Perfusion Imaging (PET/CT) with stress myocardial blood flow (MBF) demonstrated good diagnostic and prognostic value for CAV.

Purpose

The purpose of this study was to validate the proposed algorithm for diagnosing and prognosticating CAV by PET/CT with stress MBF in a large and contemporary series.

Methods

Patients with a history of OHT with no prior revascularization in the transplanted heart who underwent PET/CT with MBF were included in the prognostic portion of the study. For the diagnostic value of PET/CT with MBF, only patients who had a PET/CT within 12 months of coronary angiography were included. The diagnostic accuracy of PET/CT was compared to the most recent coronary angiogram. A composite outcome of death, heart failure hospitalization, acute coronary syndrome, revascularization, and re-transplantation was used to validate the prognostic ability of PET/CT with MBF.

Results

450 PET/CT scans with MBF were performed and included in the prognostic portion of the study. 78 patients had PET/CT within 12 months of coronary angiography and were included in the diagnostic portion. Normal perfusion with normal myocardial blood flow had a 100% negative predictive value for moderate-severe CAV by angiography. PET/CT CAV 2/3 had a positive predictive value of 69% for moderate-severe CAV. Over 24 months, there were 20 events in the 39 patients with a PET CAV grade of 2/3 versus 21 events in the 411 patients with a PET CAV grade of 0/1 with a hazard ratio 13.3 (p&lt;0.001).

Conclusions

The current proposed algorithm for diagnosing CAV by PET/CT with stress MBF has excellent negative predictive value along with good positive predictive value for detecting moderate-severe CAV by coronary angiography. A PET/CT with stress MBF with CAV classification of 2/3 is associated with a poor prognosis.

Funding Acknowledgement

Type of funding sources: None.

Impact of weight loss on cardiac function: improvement in left ventricular global longitudinal strain following metabolic surgery

Introduction

Obesity leads to an increased risk of cardiovascular disease (CVD) morbidity and mortality and is associated with the metabolic risk factors such as hypertension, diabetes mellitus, hyperlipidemia [1]. Metabolic surgery has been proven to be the most effective long term weight management tool and has known benefits in CVD prevention [2]. Global longitudinal strain (GLS) is an effective quantitative measurement of left ventricular (LV) function that is also a powerful predictor of future CVD events and mortality [3]. The impact of metabolic surgery on LV structure and function is unknown.

Purpose

This study investigated the changes in cardiac structure and function after metabolic surgery, including GLS. To our knowledge there has not been a study investigating this relationship previously reported.

Methods

Consecutive patients undergoing metabolic surgery at our center between March 2005 and February 2019 were recruited. Patients with transthoracic echocardiographic imaging (TTE) pre and post metabolic surgery (May 2005 to January 2019) were included. Electronic medical records were searched to obtain demographic, surgical and clinical data. GLS was calculated with Velocity Vector Imaging (VVI, Siemens, v2.0, Pennsylvania, USA). Averaged GLS values were derived from 4 chamber, 2 chamber and 3 chamber calculations.

Results

398 patients with pre- and post-operative cardiac imaging were included. Please see Table 1 for the baseline demographics of our study population. The mean age was 60.0 years with 70% being female. There were significant rates of CVD risk factors such as: hypertension (76.4%), diabetes mellitus (58.8%) and hyperlipidemia (76.4%).

The clinical and echocardiographic changes noted post metabolic surgery are detailed in Table 2. Along with decreases in weight post operatively, there were significant improvements in the markers of CVD risk factors such as mean blood pressure (134/75 to 129/72 mmHg, p value &lt;0.001), mean gylcated hemoglobin levels (7.0 to 6.1%, p value &lt;0.001) and mean low density lipoprotein (LDL) levels (97.7 to 88.2 mg/dl, p value &lt;0.001).

There were a number of statistically significant positive changes in the left ventricular structure and function. The mean LV ejection fraction increased from 56.3% to 57.4% (p=0.008); left ventricular mass decreased from 238.2 g to 179.3 g (p value &lt;0.001), and both septal and posterior wall thicknesses decreased significantly (p value &lt;0.001). The LV mass indexed to body surface area (BSA) also decreased from 93.5 g/m2 to 83.1 g/m2.

The average global LV GLS was −15.7% pre-operatively, improving significantly to −17.9% post-operatively (p&lt;0.001).

Conclusion

Our study has shown for the first time the impact of metabolic surgery on ventricular structure and function, with reduction in LV mass and improvement in LV GLS. These novel findings lends further support to the cardiovascular benefits of metabolic surgery.

Funding Acknowledgement

Type of funding sources: None.

Post-systolic shortening index by echocardiography evaluation of dyssynchrony in the non-dilated and hypertrophied left ventricle

Background

Post-systolic shortening index (PSI) is defined as myocardial shortening that occurs after aortic valve closure, and is an emerging measure of regional LV contractile dysfunction. PSI measurement variability amongst software vendor and its relationship with mechanical dyssynchrony and mechanical dispersion index (MDI) remains unknown. We evaluated PSI by speckle-tracking echocardiography from several vendors in patients with increased left ventricular wall thickness, and associations with MDI.

Methods

This is a prospective cross-sectional study of 70 patients (36 hypertrophic cardiomyopathy [HCM], 18 cardiac amyloidosis and 16 healthy controls) undergoing clinically indicated echocardiography. PSI was measured using QLAB/aCMQ (Philips), QLAB/LV auto-trace (Philips), EchoPAC (GE), Velocity Vector Imaging (Siemens), and EchoInsight (EPSILON) software packages, and calculated as 100% × (post systolic strain − end-systole strain)/post systolic strain.

Results

There was a significant difference in mean PSI among controls 2.1±0.6%, HCM 6.1±2.6% and cardiac amyloidosis 6.8±2.7% (p&lt;0.001). Variations between software vendors were significant in patients with pathologic increases in LV wall thickness (for HCM p=0.03, for amyloidosis p=0.008), but not in controls (p=0.11), as seen in Figure 1. Furthermore, there were moderate correlations between PSI and both MDI (r=0.77) and left ventricular global longitudinal strain (r=0.69), as seen in Figure 2.

Conclusion

PSI was greater in HCM and cardiac amyloidosis patients than controls, and a valuable tool for dyssynchrony evaluation, with moderate correlations to MDI and strain. However, there were significant variations in PSI measurements by software vendor especially in patients with pathological increase in LV wall thickness, suggesting that separate vendor-specific thresholds for abnormal PSI are required.

Funding Acknowledgement

Type of funding sources: None.

Real-world application of tumor mutational burden-high (TMB-high) and microsatellite instability (MSI) confirms their utility as immunotherapy biomarkers

Introduction

Microsatellite instability (MSI) testing and tumor mutational burden (TMB) are genomic biomarkers used to identify patients who are likely to benefit from immune checkpoint inhibitors. Pembrolizumab was recently approved by the Food and Drug Administration for use in TMB-high (TMB-H) tumors, regardless of histology, based on KEYNOTE-158. The primary objective of this retrospective study was real-world applicability and use of immunotherapy in TMB/MSI-high patients to lend credence to and refine this biomarker.

Methods

Charts of patients with advanced solid tumors who had MSI/TMB status determined by next generation sequencing (NGS) (FoundationOne CDx) were reviewed. Demographics, diagnosis, treatment history, and overall response rate (ORR) were abstracted. Progression-free survival (PFS) was determined from Kaplan–Meier curves. PFS1 (chemotherapy PFS) and PFS2 (immunotherapy PFS) were determined for patients who received immunotherapy after progressing on chemotherapy. The median PFS2/PFS1 ratio was recorded.

Results

MSI-high or TMB-H [≥20 mutations per megabase (mut/MB)] was detected in 157 adults with a total of 27 distinct tumor histologies. Median turnaround time for NGS was 73 days. ORR for most recent chemotherapy was 34.4%. ORR for immunotherapy was 55.9%. Median PFS for patients who received chemotherapy versus immunotherapy was 6.75 months (95% confidence interval, 3.9-10.9 months) and 24.2 months (95% confidence interval, 9.6 months to not reached), respectively (P = 0.042). Median PFS2/PFS1 ratio was 4.7 in favor of immunotherapy.

Conclusion

This real-world study reinforces the use of TMB as a predictive biomarker. Barriers exist to the timely implementation of NGS-based biomarkers and more data are needed to raise awareness about the clinical utility of TMB. Clinicians should consider treating TMB-H patients with immunotherapy regardless of their histology.

•

This retrospective study examined the real-world use of immune checkpoint inhibitors (ICIs) in TMB/MSI-high patients with a diverse set of cancer types.

•

TMB is an emerging tumor-agnostic biomarker for response to treatment with ICIs that may expand personalized cancer care.

•

ICIs remain underutilized as a first-line therapy for TMB/MSI-H patients without specific histologic approval for ICIs.

•

The PFS2 to PFS1 ratio was 4.7, favoring immunotherapy over chemotherapy even as a second-line therapy.

•

Our study reinforces the real-world evidence that TMB is a valid surrogate marker for MSI and can predict response to ICIs.

Left atrial strain evaluation and prognostic value in constrictive pericarditis patients undergoing pericardiectomy

Background

Left Atrial (LA) phasic volumes analyses is flawed with geometrical assumption requiring high endocardial border definition. LA strain analysis is an emergent technique that overcome some of these technical limitations. Prior studies of LA mechanics in pericardiectomy patients found improvement in LA strain at follow-up and manifested as symptomatic improvement, however their relationships with survival have not been investigated.

Purpose

We assessed LA strain before and after pericardiectomy and its association with all- cause mortality.

Methods

Consecutive patients with constrictive pericarditis who underwent pericardiectomy from 2000–2017 were retrospectively analyzed, analyzing pre-operative and post-operative (at 12 months) echocardiography. Exclusion criteria included atrial fibrillation, previous left sided valve surgery, concomitant valvular surgery at the index pericardiectomy, more than mild left sided valvulopathy and poor echocardiographic windows. Strain analyses was performed with Vector velocity imaging independent software. Univariate and multivariable analyses were utilized to identify factors associated with reduced survival.

Results

Amongst 190 patients included in the analyses, mean age was 58.5±12.7 years and 37 (19.5%) were female. The etiology of constriction was deemed idiopathic in 61.6% of the cases, median time interval surgery-postoperative echo was 67 days (IQR 6, 312 days). During median follow up of 3.3 years (IQR 0.73, 5.9 years) there were 37 deaths. After surgery, there was a significant decrease in LA reservoir, conduit and regional wall strains. (Table 1). Multivariable analysis demonstrated that postoperative 4C AL strain reservoir was independently associated with all-cause mortality (Table 2).

Conclusions

In pericardiectomy patients, postoperative 4C LA strain reservoir is independently associated with all-cause mortality. Perhaps, compensatory changes of septal and antero-posterior walls during constriction explain why after surgery these walls become less dynamic, negatively impacting the overall function. Overall, LA quantification and strains may become a useful clinical tool for risk stratification in pericardiectomy patients

Funding Acknowledgement

Type of funding sources: None. Table 1. Left atrial variables.Table 2. All-cause mortality predictors

Associations and outcomes of cardiovascular calcifications by computed tomography in atrial fibrillation patients

Background

Coronary (CAC), mitral annular (MAC), aortic valve (AVC) and thoracic aortic (TAC) calcifications are known imaging biomarkers for cardiovascular risk in the general population. Despite this, their prognostic value are not well established in atrial fibrillation (AF) patients who have elevated risk for cardiovascular events.

Purpose

We assessed the associated factors and outcomes of cardiovascular calcifications detected by computed tomography (CT) in AF patients undergoing pulmonary vein isolation (PVI).

Methods

Consecutive AF patients enrolled in a prospective PVI registry during 2014–2018 with CT performed within 1-year of their procedure were reviewed for the presence of cardiovascular calcifications on CT. Risk factors and outcomes for each type of cardiovascular calcifications were analyzed in univariable and multivariable regression models.

Results

Amongst 3604 AF patients, there were 2238 (62.1%), 308 (8.6%), 572 (15.9%) and 1048 (29.1%) patients with CAC, MAC, AVC and TAC respectively. Factors independently associated with these cardiovascular calcifications are listed in Table 1. During mean follow-up of 2.8±1.6 years, there were 97 (2.7%) all-cause deaths, and 158 (4.4%) major adverse cardiovascular events (MACE). Forest plots of unadjusted and adjusted hazards ratios of cardiovascular calcifications at predicting these outcomes are shown in Figure 1.

Conclusion

Cardiovascular calcifications especially CAC are prevalent in AF patients, and share common risk factors with cardiovascular events, except for female being protective for CAC and AVC but having higher risk of MAC and TAC. Although all cardiovascular calcifications were associated with death and MACE in unadjusted analyses, only CAC remained so for both outcomes in adjusted analyses.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): National Heart Foundation of New Zealand Table 1Figure 1

Evaluating direct oral anticoagulants versus vitamin K antagonists for treatment of left ventricular thrombus: a systematic review and meta-analysis

Background/Introduction

Left ventricular thrombi are associated with high rates of stroke and systemic embolism (1). While vitamin K antagonists (VKAs) have historically been the anticoagulant of choice, they have a narrow therapeutic window and require frequent monitoring. Direct oral anticoagulants (DOACs) offer more predictable anticoagulation but the use of DOACs to treat left ventricular thrombus has not been well studied (1,2). Guideline recommendations around the topic are based on expert consensus and very low-quality evidence.

Purpose

This systematic review and meta-analysis compares DOACs or VKAs in the treatment of left ventricular thrombus. Outcomes of interest were stroke and systemic embolism, thrombus resolution, any bleeding, major bleeding, and mortality.

Methods

We searched CENTRAL, MEDLINE, EMBASE, CINAHL, ACPJC, and Web of Science for studies comparing DOACs and VKAs in the treatment of left ventricular thrombus. We also searched reference lists from included studies and relevant conferences' proceedings. Two reviewers independently screened titles and abstracts and then the full-text of potentially relevant citations in duplicate. They then extracted data and evaluated risk of bias in duplicate. The data was analyzed using Revman 5.3. We used the DerSimonian and Laird random-effects model to pool the weighted effect of estimates across all studies. The pooled relative risks (RRs) were calculated with corresponding 95% confidence intervals (CIs). We assessed the quality of evidence for each outcome using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

Results

Of 443 citations screened, 12 observational studies (n=2,225) were included. We found no randomized controlled trial addressing the question. Most included studies were at high risk of bias due to unmatched baseline variables. We found no significant difference in any of our outcomes with DOACs versus VKAs: stroke and systemic embolism (RR 1.14, 95% CI [0.82, 1.58], p=0.43), thrombus resolution (RR 1.02, 95% CI [0.91, 1.15], p=0.69), any bleeding (RR 1.47, 95% CI [0.65, 3.33], p=0.36), major bleeding (RR 0.22, 95% CI [0.01, 4.21], p=0.32), and mortality (RR 0.99, 95% CI [0.67, 1.45], p=0.95). Evidence for each of these outcomes was of very low-quality due to risk of bias, inconsistency, and imprecision of the studies.

Conclusions

Very low quality evidence suggests no difference in outcomes with DOACs versus VKAs in the treatment of left ventricular thrombus. More robust data are needed to guide clinicians.

Funding Acknowledgement

Type of funding sources: None.

Survey of research participation amongst UK radiology trainees: aspirations, barriers, solutions and the Radiology Academic Network for Trainees (RADIANT)

AIM

To inform the activity of the newly formed Radiology Academic Network for Trainees (RADIANT) regarding the current level of interest, engagement, and barriers experienced by UK radiology trainees to undertake research.

MATERIALS AND METHODS

A web-based survey containing nine questions was sent to the UK radiology training programme directors for distribution to trainees. The survey was also distributed to all trainee members of the RADIANT network. This led to 224 responses over a period of 2 months.

RESULTS

A large proportion of respondents indicated a desire to participate in research in the next 12 months 72.3% (n=162). The most frequently reported barriers to research were lack of time (60.7%, n=136), lack of awareness of local/departmental opportunities (53.6%, n=120), and limited experience in research statistics (46%, n=103). The most favoured factor that would improve access to research was structured research training opportunities, qualified as a project with clear goals and timeline (71%, n=159), protected time for research (68.8%, n=154), and local or national trainee research networks (40.2%, n=90 and 37.1%, n=83, respectively).

CONCLUSION

Many radiology trainees would like to participate in research, but multiple barriers exist. The formation of RADIANT is seen as a key part of a multifaceted approach to improving access to quality research activity alongside support from local and regional training bodies.

PEAR1 rs12041331 polymorphisms and the risk of adverse cardiovascular outcomes in patients with acute coronary syndrome and/or percutaneous coronary intervention: a systematic review and meta-analysis

Background

Platelet endothelial aggregation receptor-1 (PEAR1), expressed in endothelium, platelets, and other tissues, is a platelet transmembrane tyrosine kinase receptor involved in platelet aggregation and platelet-platelet contact. The minor allele (A) in intron 1 of the PEAR1 gene (rs12041331, G&gt;A) is associated with an reduced PEAR1 protein expression and suppressed platelet aggregation response toward multiple agonists. But current evidences on the association between PEAR1 rs12041331 polymorphisms and cardiovascular outcomes in patients with acute coronary syndrome (ACS) and/or percutaneous coronary intervention (PCI) are discordant.

Purpose

To characterize and quantify the association between PEAR1 rs12041331 polymorphisms and cardiovascular outcomes in patients with ACS and/or PCI.

Methods

We conducted a systematic review and meta-analysis by searching MEDLINE via PubMed, EMBASE, Cochrane Central Register of Controlled Trials, SinoMed, CNKI, and Wanfang Data before Dec 7, 2019 to identify studies evaluating the association between PEAR1 rs12041331 polymorphisms and cardiovascular outcomes in patients with ACS and/or PCI. The primary outcome was the major adverse cardiovascular outcomes (MACEs) defined by each study. We adopted the Mantel-Haenszel method to calculate the relative risks (RRs) with 95% confidence intervals (CIs) and the corresponding P values using the random effect model. To assess the effect of ethnicity, we performed the subgroup analyses per ethnic population using the fix effect model.

Results

Among 542 citations identified along with 1 from additional sources, we included 4 studies, which documented 218 MACEs in 8180 patients. The A allele frequency in each study was comparable with that reported in the 1000 Genome Project, but varied among ethnic populations, that is 45.8% in East Asians, 46.5% in American Africans, and 9.2% in Caucasians, adopted from the 1000 Genome Project. A-allele carriers are associated with a 54% increase in MACEs than non-A-carriers (RR, 1.54; 95% CI, 1.10–2.16; P=0.01) with a low but non-significant heterogeneity. Subgroup analyses showed that A-allele carriers tend to have more MACEs than non-A-allele carriers despite of ethnicity, that is 1.32-fold increase in East Asians (RR, 1.32; 95% CI, 0.99–1.77; P=0.06), 2.43-fold in Caucasians (RR, 2.43; 95% CI, 0.99–5.98; P=0.05), and 3.56-fold (RR, 3.56; 95% CI, 1.08–11.70; P=0.04) in American Africans.

Conclusions

Our study indicates that the PEAR1 rs12041331 is prognostic in patients with ACS and/or PCI and treated with DAPT, which might be not caused by the associations with pharmacological response to antiplatelet agents. Further investigations are thus required to address the unrevealing mechanisms of PEAR1, especially on the development of atherosclerosis and the occurrence of acute adverse ischemic events.

Figure 1

Funding Acknowledgement

Type of funding source: None

Genetic polymorphisms and cardiovascular outcomes in Chinese patients undergoing PCI and treated with clopidogrel and aspirin

Background

Genetic polymorphisms of key proteins involved in clopidogrel absorption, metabolism, and action may contribute to variability in platelet inhibition in patients undergoing percutaneous coronary intervention (PCI), but their impacts on cardiovascular outcomes remain unclear.

Purpose

To examine the associations between genetic polymorphisms and cardiovascular outcomes in Chinese patients undergoing PCI and treated with clopidogrel and aspirin.

Methods

This prospective cohort study consecutively enrolled 2,453 post-PCI patients treated with clopidogrel and aspirin. Adenosine diphosphate-induced platelet aggregation was measured by light transmission aggregometry. A total of 40 single nucleotide polymorphisms (SNPs) of 18 genes selected according to published studies were investigated using an improved multiplex ligation detection reaction technique. The primary outcome was major adverse cardiovascular event (MACE), the composite of cardiovascular death, non-fatal myocardial infarction (MI), and ischemic stroke within one year after PCI.

Results

We restricted the analyses to the first 1,452 patients who had finished one-year follow-up and complete data on genotyping and platelet aggregation. 44 (3.03%) patients suffered MACE. Among the 40 SNPs, only the A-allele carriers of CYP2C19*2 had a significant higher risk of MACE (adjusted HR 2.05; 95% CI, 1.01–4.19; p=0.048) and platelet aggregation than non-A-carriers after adjusting age, sex, MI presentation, and left ventricular ejection fraction. CYP2C19*3, CYP2B6 rs3745274, and PEAR1 rs12041331 variants were also significantly associated with platelet aggregation (all p&lt;0.05) but not with MACE at 1 year.

Conclusion

About 54.2% of Chinese patients with PCI were A-allele carriers of CYP2C19*2, who face a two-fold higher risk of MACE than non-A-allele carriers in Chinese patients after PCI. It would help identify low clopidogrel responders and optimize antiplatelet therapy before drug administration.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Natural Science Funding of China

Improved tolerability of neratinib in patients with HER2-positive early-stage breast cancer: the CONTROL trial

BACKGROUND

Neratinib is an irreversible pan-HER tyrosine kinase inhibitor approved for extended adjuvant treatment in early-stage HER2-positive breast cancer based on the phase III ExteNET study. In that trial, in which no antidiarrheal prophylaxis was mandated, grade 3 diarrhea was observed in 40% of patients and 17% discontinued due to diarrhea. The international, open-label, sequential-cohort, phase II CONTROL study is investigating several strategies to improve tolerability.

PATIENTS AND METHODS

Patients who completed trastuzumab-based adjuvant therapy received neratinib 240 mg/day for 1 year plus loperamide prophylaxis (days 1-28 or 1-56). Sequential cohorts evaluated additional budesonide or colestipol prophylaxis (days 1-28) and neratinib dose escalation (DE; ongoing). The primary end point was the incidence of grade ≥3 diarrhea.

RESULTS

Final data for loperamide (L; n = 137), budesonide + loperamide (BL; n = 64), colestipol + loperamide (CL; n = 136), and colestipol + as-needed loperamide (CL-PRN; n = 104) cohorts, and interim data for DE (n = 60; completed ≥six cycles or discontinued; median duration 11 months) are available. No grade 4 diarrhea was observed. Grade 3 diarrhea rates were lower than ExteNET in all cohorts and lowest in DE (L 31%, BL 28%, CL 21%, CL-PRN 32%, DE 15%). Median number of grade 3 diarrhea episodes was one; median duration per grade 3 episode was 1.0-2.0 days across cohorts. Most grade 3 diarrhea and diarrhea-related discontinuations occurred in month 1. Diarrhea-related discontinuations were lowest in DE (L 20%, BL 8%, CL 4%, CL-PRN 8%, DE 3%). Decreases in health-related quality of life did not cross the clinically important threshold.

CONCLUSIONS

Neratinib tolerability was improved with preemptive prophylaxis or DE, which reduced the rate, severity, and duration of neratinib-associated grade ≥3 diarrhea compared with ExteNET. Lower diarrhea-related treatment discontinuations in multiple cohorts indicate that proactive management can allow patients to stay on neratinib for the recommended time period. CLINICALTRIALS.GOV: NCT02400476.

Transradial Woven EndoBridge device to treat a ruptured basilar tip aneurysm under conscious sedation

We present a patient with a ruptured basilar tip aneurysm treated under conscious sedation via a right radial approach using the Woven EndoBridge device. We discuss the technical aspects of the case as the well as the available literature on the treatment of ruptured aneurysms treated without general anaesthesia. We discuss the potential benefits of the Woven EndoBridge device in such situations.

Abstract P2-13-03: The impact of neratinib with or without anti-diarrheal prophylaxis on health-related quality of life in HER2+ early-stage breast cancer: Analyses from the ExteNET and CONTROL trials

Background: Neratinib is an irreversible pan-HER tyrosine kinase inhibitor. ExteNET, a randomized placebo-controlled phase III study, showed that neratinib given for 12 months after trastuzumab-based adjuvant therapy significantly improved 2-year (HR 0.67; 95% CI 0.50–0.91; p=0.0091) and 5-year (HR 0.73; 95% CI 0.57-0.92; p=0.008) iDFS in pts with early-stage HER2+ breast cancer. Anti-diarrheal prophylaxis was not mandated by protocol; grade 3/4 diarrhea occurred in 40% of pts with a median cumulative duration of 5 days. The phase II CONTROL study was initiated to investigate the effectiveness of various prophylactic regimens in the prevention of neratinib-associated diarrhea. Loperamide (L) alone or in combination with add-on agents targeting underlying inflammation [i.e. budesonide (BUD)] or bile acid malabsorption [i.e. colestipol (COL)] were tested. We report longitudinal HRQoL findings from both ExteNET and CONTROL.

Methods: Pts with early-stage HER2+ breast cancer who had received trastuzumab-based adjuvant therapy were eligible for both studies. In ExteNET, pts received neratinib or placebo for 12 months. In CONTROL, pts received neratinib for 13 x 28-day cycles combined with L, L + BUD or L + COL for 1 or 2 cycles (see table for schedules). HRQoL was assessed using Functional Assessment of Cancer Therapy–Breast (FACT-B), v4.0, at baseline, months 1, 3, 6, 9, 12 (ExteNET) or baseline, cycles 2, 4, 7, 10, 13 (CONTROL). Changes in scores from baseline were considered to be clinically meaningful if greater than the lowest estimate for an 'important difference' (ID) reported in the literature. Evaluable pts were required to have HRQoL assessments at baseline and at least 1 post-baseline. ClinicalTrials.gov: NCT00878709 (ExteNET); NCT02400476 (CONTROL).

Results: HRQoL findings are summarized in the table. Hospitalization rates due to diarrhea: 1.5% (neratinib + L), 0% (other cohorts) in CONTROL; and 1.4% (neratinib), 0.1% (placebo) in ExteNET.

  Mean change from baselineStudyCohort/GroupM1M3M6M9M12 FACT-B TOTAL (ID range: 7–8 points)CONTROLN + La,b (N=40)–3.8–4.5–1.5–2.5–3.3 N + L + BUDa,b,c (N=62)–6.0–4.9–1.6–3.6–4.5 N + L + COLa,b,d (N=125)–3.8–2.0–4.0–4.6–3.6 N + L prn + COLa,d (N=85)–1.8–1.54.0e––ExteNETN + L prna (N=1124)–4.6–3.4–3.5–3.3–3.7 P (N=1188)–1.7–3.5–2.9–2.9–2.8 FACT-B PWB (ID range: 2–3 points)CONTROLN + La,b (N=40)–4.0–2.3–1.9–2.4–2.3 N + L + BUDa,b,c (N=62)–3.2–2.1–1.4–1.7–1.7 N + L + COLa,b,d (N=125)–2.8–2.0–2.4–2.5–2.4 N + L prn + COLa,d (N=85)–2.8–1.80.0e––ExteNETN + L prna (N=1124)–2.9–1.9–1.7–1.6–1.5 P (N=1188)–0.6–0.8–0.7–0.6–0.4C, cycle; L, loperamide; M, month; N, neratinib; prn, as needed; PWB, physical well-being. CONTROL cut-off: 1 May 2018. aN 240 mg qd for 13 x 28d cycles or 12 months; bL 4 mg, then 4 mg tid d1-14, then 4 mg bid d15-28 or d15-56, then prn; cBUD 9 mg qd d1-28; dCOL 2 g qd d1-28; en=1.

Conclusions: Adjuvant neratinib with or without anti-diarrheal prophylaxis was associated with small decreases in HRQoL. With the exception of the FACT-B PWB subscale, HRQoL changes did not reach clinically meaningful thresholds. Follow-up in CONTROL is ongoing.

Citation Format: Delaloge S, Hurvitz S, Chan N, Bose R, Jankowitz RC, Thirlwell M, Láng I, ten Tije A, Trudeau M, Osborne CR, Shen Z-Z, Lalla D, Xu F, Hunt D, Olek E, Tripathy D, Rugo HS, Chien J, Chan A, Barcenas CH. The impact of neratinib with or without anti-diarrheal prophylaxis on health-related quality of life in HER2+ early-stage breast cancer: Analyses from the ExteNET and CONTROL trials [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-13-03.

Abstract P1-15-14: Neoadjuvant liposomal doxorubicin and carboplatin is effective and tolerable for the treatment of triple negative breast cancer

Background: The use of neoadjuvant platinum with taxane for triple negative breast cancer (TNBC) has gained increased attention for improving rates of pathologic complete response (pCR). Our prior trial combining carboplatin (CAR) with liposomal doxorubicin (DOX) for metastatic TNBC showed good response rates with minimal side effects while allowing for greater platinum dosing compared to a taxane combination. We hypothesized that the doublet of DOX+CAR is effective and tolerable in the neoadjuvant setting for TNBC and that tumor genomics may aid in determining those patients most likely to benefit.

Methods: A phase II single arm trial was conducted for patients (pts) diagnosed with stage II-III TNBC. Patients received 4 cycles of neoadjuvant carboplatin (AUC 5) and liposomal doxorubicin (30mg/m2) administered every 28 days, then underwent definitive breast surgery followed by 12 weeks of adjuvant paclitaxel 80 mg/m2 administered weekly. Primary and secondary clinical endpoints were rate of pCR and two year recurrence free survival (RFS) and overall survival (OS), respectively. Cardiac safety of the combination was assessed. Fresh residual tumor samples were obtained at time of surgery for generation of patient derived xenografts (PDX). Tumor genomic profiling was done to determine the mutational spectrum, association of this spectrum in primary tumors with achieving pCR, and identifying alternative treatment strategies for PDX evaluation for patients with resistant disease.

Results: From 2/2015 to 5/2018, 36 pts were enrolled and 32 completed treatment; 4 pts await definitive surgery; 12 (33%) are two years from diagnosis. Median age of the cohort was 53 years. There was high participation by under-represented groups: 23% African American, 20% Asian, 14% Hispanic. Most histologies were invasive ductal but included apocrine, pleomorphic lobular, and metaplastic subtypes. Of the 32 pts who completed surgery, 34% (11) achieved pCR and 64% (23) had clinical response on serial physical exam. At 2 years, there were 2 distant and 1 local recurrence. The most common toxicities during DOX+CAR were grade 1 nausea in 19 pts (53%), grade 3/4 neutropenia occurred in 10 pts (28%); these pts received GCSF support with subsequent cycles; febrile neutropenia occurred in 1 pt (3%) in this group. Grade 3 thrombocytopenia (2 pts), pruritis (1 pt), and mucositis (1 pt) were observed. Only 6 pts (17%) had grade 1 alopecia. There were no delays in treatment due to cardiotoxicity or complications from surgical healing. TP53 (93%), PI3K/PTEN (26.6%), and NOTCH (20%) were the most commonly altered pathways. Structural variants, such as amplifications, rearrangements, and frameshifts were the most frequent alterations detected. Of the 25 pts who had residual disease, PDX was attempted from 14 pts, and 10 (71%) PDX were established, including those for all 3 patients experiencing recurrence.

Conclusion: Neoadjuvant DOX+CAR demonstrated good efficacy and tolerability. Post-chemotherapy PDX is feasible and may help identify targeted approaches for patients with resistant disease. These results warrant further evaluation of this combination for early stage TNBC.

Citation Format: Chan N, Riedlinger GM, Lu S-e, Pham KT, Kirstein LJ, Eladoumikdachi FG, George MA, Potdevin LB, Kowzun MJ, Desai SA, Tang DM, Omene CO, Wong ST, Rodriguez-Rust L, Kumar S, Kearney TJ, Liu C, Ganesan S, Toppmeyer DL, Hirshfield KM. Neoadjuvant liposomal doxorubicin and carboplatin is effective and tolerable for the treatment of triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-14.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Comparison of the ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations

Essentials Routine monitoring is unnecessary but measuring dabigatran levels is helpful in certain situations. We compared ecarin chromogenic assay (STA-ECA-II) and dilute thrombin time (dTT) in patient samples. Both tests provided accurate measurements over a wide range of dabigatran concentrations. Adoption of STA-ECA-II and dTT into routine clinical practice will improve patient care.

SUMMARY

Background Although routine coagulation monitoring is unnecessary, measuring plasma dabigatran concentrations can be useful for detecting drug accumulation in renal failure or overdose, assessing the contribution of dabigatran to serious bleeding, planning the timing of urgent surgery or intervention, or determining the suitability for thrombolytic therapy for acute ischemic stroke. Dabigatran concentrations can be quantified using chromogenic or clot-based tests, such as the ecarin chromogenic assay (ECA) and the diluted thrombin time (dTT), respectively. Objective The purpose of this study was to compare the results of these assays with dabigatran concentrations measured by the reference standard of mass spectrometry in samples from 50 dabigatran-treated patients collected at peak and trough after at least 4 months of drug intake. Methods Drug levels measured with either the STA Ecarin Chromogenic Assay-II (STA-ECA-II) or dTT were linearly correlated with those determined by mass spectrometry over a wide range of concentrations. Results and Conclusions For detection of levels below 50 ng mL-1 both tests have specificities of at least 96%, suggesting that they accurately detect even low levels of drug. Therefore, regardless of whether a chromogenic or clot-based platform is preferred, the STA-ECA-II and dTT are useful tests for measuring dabigatran concentrations. Unfortunately, neither test is licensed by the United States Food and Drug Administration. Although approved in other jurisdictions, the dTT and STA-ECA-II are not widely or rapidly available in most hospitals. Therefore, cooperation between regulators and hospitals is urgently needed to render these tests readily available to inform patient care.

Abstract P4-22-21: NCI9782: A phase 1 study of talazoparib in combination with carboplatin and paclitaxel in patients with advanced solid tumors

Background: Poly(ADP-ribose) polymerase (PARP) enzymes are involved in DNA repair and activated by DNA strand breaks. DNA damage from carboplatin is associated with activation of PARP. Preclinical data indicate that PARP inhibition potentiates the anti-tumor effect of platinum chemotherapy. Talazoparib (T) is an oral, selective PARP inhibitor with a single agent maximum tolerated dose (MTD) of 1mg orally qd. Primary dose-limiting toxicity (DLT) was thrombocytopenia. This phase I study combines T with the commonly used chemotherapy regimen of carboplatin (C) and paclitaxel (P).

Methods: Two dosing schedules are being investigated. In both schedules, C is administered on day 1 and P on days 1, 8, and 15 of a 21-day cycle. T (100-1000mcg) is dosed once daily for days 1-7 (schedule A) or days 1-3 (schedule B) starting on day 1. A 3+3 design is used for dose escalation. Key eligibility criteria include age 318 with a measurable or evaluable solid incurable malignancy. Patients (pts) must have tumor type that is expected to respond to C + P or have BRCA germline or somatic mutation. Stable, treated brain metastases are allowed. No prior C for metastatic disease is allowed. Pts must have platelets&gt;150 and no need for anticoagulation. After 4-6 cycles of combination therapy, pts may continue the combination, change to C and intermittent T without P or change to T alone with continuous daily dosing. Each schedule will have a 6 subject dose expansion at the MTD. The starting dose level for schedule B will be the MTD from schedule A.

Results: Schedule A cohort results are reported: 11 pts (median age 59 [range 39-68]; 8 female; 3 male) have been enrolled. Pts had breast (6), ovarian (2), pancreatic (1), and SCC of oropharynx (1) and concurrent ovarian and pancreatic (1). Five pts are BRCA2+ and 3 pts are BRCA1+. Dose level 3 on schedule A (T 350mcg with C AUC 6 and P 80mg/m2) exceeded the MTD with 2 of 3 pts experiencing hematologic dose limiting toxicities (DLTs) including 1 pt with grade (gr) 3 neutropenic fever and gr 4 thrombocytopenia and another pt with grade 3/4 neutropenia lasting &gt; 7 days. Most common AEs include neutropenia (grade 3-4: 7), anemia (grade 3-4: 3), and thrombocytopenia (grade 3-4: 4). Results from expansion of dose level 2 (T 250mcg with C AUC 6 and T 80mg/m2) will be presented. The 11 pts were on study a median of 9 weeks (range 9-36+). Four pts have discontinued study therapy: 1 due to need for anticoagulation for PE, 1 for prolonged cytopenias, and 2 for disease progression. Of the 8 pts with measurable disease evaluated for response to date, 4 had SD, 1 had a cPR, 1 had radiographic CR, and 2 with PD. A pt with BRCA 1+ triple negative breast cancer has maintained a prolonged PR (36+ weeks) even after dose reductions to T 100mcg with C AUC 3. One pt with ovarian cancer (BRCA WT) has radiographic CR (CA 125 remains mildly elevated) after 15+ weeks of therapy.

Conclusion: PARP inhibition with talazoparib days 1-7 in combination with carboplatin and paclitaxel leads to DLT of myelosuppression. However, clinical responses are seen even with lower dose combinations.

Citation Format: Turk A, Chan N, Leal T, O'Regan R, Tevaarwerk A, Rice L, Campbell T, Barroilhet L, Mehnert J, Eickhoff J, Kolesar J, Liu G, Wisinski K. NCI9782: A phase 1 study of talazoparib in combination with carboplatin and paclitaxel in patients with advanced solid tumors [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-21.

The Mechanical Properties of Conventional and Auxetic Foams. Part II: Shear

Auxetic materials with a negative Poisson's ratio have the fascinating property of expanding laterally when stretched longitudinally. This property is fundamentally important to the properties of a material, and significant changes in the value of the ratio have important effects on mechanical performance. This paper examines the variation in static and dynamic shear moduli on a range of auxetic foams and also examines variation in loss tangent. It is shown that both the static, elastic shear modulus and the dynamic loss tangent may increase with a negative Poisson's ratio. Such changes are attributed to modifications of the cell structure of the foam, not to changes in the material of the foam, during conversion to an auxetic foam. Such changes may have important applications in cushioning, packaging, sound absorption and protection.

The Mechanical Properties of Conventional and Auxetic Foams. Part I: Compression and Tension

Auxetic foams exhibit the unusual property of a negative Poisson's ratio and hence expand laterally when stretched. In this, the first of two papers, a systematic study is made of the mechanical properties of a range of foams fabricated to have different negative Poisson's ratios. The stress-strain behaviour, in both tension and compression, is compared with conventional foams. Values for the Young's moduli and Poisson's ratios in the three principal directions, in both tension and compression, are obtained. Negative Poisson's ratios ranging between -0.2 and -0.9 in tension, and between -0.1 and -0.8 in compression have been obtained. The effect of densification, during loading is significantly enhanced in auxetic foams, and this significantly affects the stress-strain curves. The creep resistance of the foams is also examined.

Indentation Resilience of Conventional and Auxetic Foams

Materials with a negative Poisson's ratio (auxetic materials) demonstrate the fascinating property of becoming fatter when stretched. This phenomenon is fundamentally important to the properties of a material and a significant change in the value of the ratio has significant effects on the material's mechanical performance. This article describes foams with a negative Poisson's ratio that show better indentation resilience than conventional foams with a positive Poisson's ratio. The unusual mechanical properties of auxetic foams are attributed to the deformation characteristics of re-entrant (concave polyhedral) cell structures.

Abstract P3-03-02: Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice

Background and Purpose: Despite recent progress in our endocrine therapy of hormone receptor positive (HR+) breast cancers, a significant number of patients with primary breast cancer continue to relapse, and those with stage IV disease face a median overall survival of ∼ 3.5 years. Primary or acquired resistance to anti-estrogen-based therapies is an overarching challenge. To guide our treatment selection, there is an essential need to improve our understanding of the biology of HR+ breast tumors responsive to and those resist to anti-estrogens or aromatase inhibitors (AIs). The application of patient-derived xenografts (PDXs) in preclinical studies has begun to open the door to mimicking human disease on the research bench. However, HR+ breast cancer PDXs are difficult to establish. Although preclinical data from DeRose et al [Nat. Med. 2011: 17:1514-1520] indicate that the rate of engraftment serves as an independent predictor for poor outcome, the question which has not yet been adequately addressed is: "why some tumors can grow in mice, and some don't, even when their clinical, pathological stage and subtype (i.e. ER positivity) are same?" Here, we hypothesize that the molecular characteristics of patient HR+ tumors are key determinants to the tumor intake rate in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. Hence, reverse phase protein array (RPPA) analysis has be performed using human patient tumors to identify driver-pathways that impact tumor intake in NSG mice.

Results and Discussion: We compared the protein expression profile of six HR+ patient tumors (four HR+ and two HR+ HER2+), which were successfully engrafted into NSG mice and established as PDX models, with the patient tumors which we were unable to establish as PDX. Of 90 patient HR+ tumors which failed to transplant, 21 tumors were picked to match the tumor type (all of them were invasive ductal carcinoma or its metastases), clinical stage and pathological grade of engrafted tumors [Table 1]. In addition to patient tumors, six established HR+ PDXs were also submitted for analysis. Quantified expressions of 272 cancer-related proteins and phospho-proteins by RPPA have been performed on these specimens. Pathways identified as predictors of intake rate of PDXs in NSG mice, and tissues from paired PDX from mice with different passages, will be evaluated for the protein expression changes to elucidate the passage effects and generate therapeutic models based on protein expression and tumor growth.

Table 1. Characteristics of the patient tumors which were successfully established as PDX modelsERPgRHER2AgePatient ethnicityClinical stageNottingham histologic scoreSource++-63Hispanic3IIIBreast tumor+--71Hispanic2IIIBreast tumor+--52African-american4N/ABrain mets+--63Caucasian4N/AChest wall mets+-+34Caucasian2IIBreast tumor+++72Caucasian4IIIChest wall metsmets: metastases

Citation Format: Kanaya N, Somlo G, Wu J, Frankel P, Wu SV, Nguyen D, Kai M, Chan N, Meng-Yin H, Kirschenbaum M, Kruper L, Vito C, Yuan Y, Hurria A, Mortimer J, Chen S. Identification of molecular pathways to define the intake rate of patient-derived hormone receptor positive (HR+) breast cancer xenografts (PDXs) in NOD/SCID/interleukin-2 receptor gamma chain null (NSG) mice. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-03-02.

Effect of standardized perioperative dabigatran interruption on the residual anticoagulation effect at the time of surgery or procedure

ESSENTIALS: Anticoagulants need to be stopped preprocedure so there is little or no remaining anticoagulant effect. We assessed the residual anticoagulant effect with standardized interruption for patients on dabigatran. With this protocol, 80-86% of patients had no residual anticoagulant effect at the time of a procedure. A standardized perioperative dabigatran protocol appears to be safe, but requires further study.

BACKGROUND

In patients taking dabigatran who require treatment interruption for a surgery/procedure, a sufficient interruption interval is needed so that there is little or no residual anticoagulant effect at the time of the surgery/procedure.

METHODS

A prospective cohort study of patients receiving dabigatran (110 mg or 150 mg twice daily) who required an elective surgery/procedure and received a standardized dabigatran interruption protocol based on surgery/procedure bleeding risk and renal function was performed. Before the surgery/procedure, a blood sample was taken for measurement of the prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and dilute thrombin time (dTT). We determined the proportion of all patients and those having a high bleeding risk surgery/procedure with normal coagulation test results at the time of the surgery/procedure. The APTT and dTT were considered to be most likely to reflect a dabigatran anticoagulant effect. Patients were followed up for 30 days postprocedure to assess for bleeding and thromboembolism.

RESULTS

One hundred and eighty-one patients were studied: 118 with low bleeding risk, and 63 with high bleeding risk. For all patients, the proportions with normal PT, APTT, TT dTT levels were 92.8%, 79.6%, 33.1%, and 80.7%, respectively. In patients with high bleeding risk, the proportions with normal PT, APTT, TT dTT levels were 93.7%, 85.7%, 57.1%, and 87.3%, respectively. During follow-up, there was one (0.6%) major bleed, there were nine (5.0%) minor bleeds, and there was one (0.6%) transient ischemic attack.

CONCLUSIONS

In patients receiving dabigatran who require an elective surgery/procedure, a standardized interruption protocol yielded 80-86% of patients with no residual anticoagulant effect at the time of surgery/procedure, and with a low incidence of bleeding.

How do we manage venous thromboembolism in pregnancy? A retrospective review of the practice of diagnosing and managing pregnancy-related venous thromboembolism at two major hospitals in Australia and New Zealand

BACKGROUND

North American and European literature suggest that the incidence rate for pregnancy-related thromboembolism (VTE) ranges from 0.5 to 2 per 1000 pregnancies. However, there is a paucity of data regarding pregnancy-related VTE in Australia and New Zealand.

AIMS

To define the epidemiology, management and adverse effects of pregnancy-related VTE in Australia and New Zealand.

METHOD

Retrospective chart review of pregnant patients with objectively diagnosed pregnancy-related VTE at Monash Medical Centre and the North Shore Hospital from January 2007 to March 2011.

RESULTS

Sixty women with VTE were identified, 31 and 29 in the antepartum and post-partum period respectively. VTE occurred as early as 8 weeks of gestation. There was a trend towards higher proportion of PE in the postpartum period. Most antenatal patients were started on enoxaparin and dosed according to weight at diagnosis. A wide variability in maintenance dosing strategies was observed. Three (5%, 95% CI: 1% to 14%) patients suffered major bleeds, all occurring post-partum. Recurrences occurred in two post-partum patients who received a truncated course of enoxaparin for distal deep-vein thrombosis. Although more women had an induction of labour, this did not translate into an increased Caesarean section rate.

CONCLUSION

The epidemiology of pregnancy-related VTE is similar to that of other developed countries. All three bleeding events occurred in the immediate post-partum setting, highlighting the need for caution at this critical time. VTE recurrences occurred in those women with post-partum distal deep-vein thrombosis treated with an abbreviated course of enoxaparin.