Long-term Cardiovascular Risks of Gonadotropin-releasing Hormone Agonists and Antagonists: a Population-based Cohort Study

AIMS

Gonadotropin-releasing hormone (GnRH) agonists and antagonists, critical medications for prostate cancer (PCa) treatment, may differ in cardiovascular safety. This prospective cohort study aimed to compare the long-term cardiovascular risks between GnRH agonists and antagonists.

MATERIALS AND METHODS

Patients with PCa receiving GnRH agonists or antagonists during 2013-2021 in Hong Kong were identified. Patients with <6 months' prescriptions, who were switching between drugs, had missing baseline prostate-specific antigen level or had a prior stroke or myocardial infarction were excluded. Patients were followed up until September 2021. The primary outcome was major adverse cardiovascular events (MACE) as in the PRONOUNCE trial (MACE_PRONOUNCE), i.e. a composite of all-cause mortality, stroke and myocardial infarction. The secondary outcome was MACE_CVM, i.e. a composite of cardiovascular mortality, stroke and myocardial infarction. Inverse probability treatment weighting was used to balance covariates between groups. The Log-rank test was used to compare the cumulative freedom from the primary outcome between groups.

RESULTS

In total, 2479 patients were analysed (162 GnRH antagonist users and 2317 agonist users; median age 75.0 years, interquartile range 68.0-81.6 years). Inverse probability treatment weighting achieved good covariate balance between groups. Over a median follow-up duration of 3.0 years (interquartile range 1.7-5.0 years), 1115 patients (45.0%) had MACE_PRONOUNCE and 344 (13.9%) had MACE_CVM. GnRH agonist users had lower risks of MACE_PRONOUNCE (Log-rank P < 0.001) and MACE_CVM (Log-rank P = 0.027). However, no differences were observed within 1 year of follow-up (MACE_PRONOUNCE: Log-rank P = 0.308; MACE_CVM: Log-rank P = 0.357). Among patients without cardiovascular risk factors at baseline, GnRH agonist users had lower risks of MACE_PRONOUNCE (Log-rank P < 0.001) and MACE_CVM (Log-rank P = 0.001), whereas no differences were observed in those with such risk factor(s) (MACE_PRONOUNCE: Log-rank P = 0.569; MACE_CVM: Log-rank P = 0.615).

CONCLUSIONS

GnRH antagonists may be associated with higher long-term, but not short-term, cardiovascular risks than agonists in Asian patients with PCa, particularly in those without known cardiovascular risk factors.

Lower risk of gout in sodium glucose cotransporter 2 (SGLT2) inhibitors versus dipeptidyl peptidase-4 (DPP4) inhibitors in type-2 diabetes patients: a propensity score-matched study

Background

The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2I) versus dipeptidyl peptidase-4 inhibitors (DPP4I) on the risk of new gout diagnosis have not been explored. This study aims to compare the effects of SGLT2I against DPP4I on gout risks in a Chinese population.

Methods

This was a retrospective population-based cohort study of patients with type-2 diabetes mellitus treated with SGLT2I or DPP4I between January 1st, 2015 and December 31st, 2020 in Hong Kong. The study outcomes are new-onset gout and all-cause mortality. Propensity score matching (1:1 ratio) between SGLT2I and DPP4I was performed. Univariable and multivariable Cox regression analysis models were conducted. Competing risks models and multiple approaches based on the propensity score were applied.

Patients

This study included 60996 patients (median age: 62.3 years old, 54.96% males; SGLTI group: n=21690; DPP4I group: n=39306).

Results

In the matched cohort, 1096 developed gout (IR: 2.52%) and 2195 died (IR: 5.05%). Univariable Cox regression showed that SGLT2I use was associated with lower risks of new diagnosis of gout (hazard ratio [HR]: 0.34; 95% confidence interval [CI]: 0.30–0.39; P-value&lt;0.0001) and all-cause mortality (HR: 0.35; 95% CI: 0.32–0.39; P-value&lt;0.0001) compared to DPP4I. The associated remained for both new diagnosis of gout (HR: 0.46; 95% CI: 0.37–0.57; P-value&lt;0.0001) and all-cause mortality (HR: 0.38; 95% CI: 0.33–0.44; P-value&lt;0.0001) after adjusting for significant demographics, past comorbidities, and non-SGLT2I/DPP4I medications. The risks of gout were lowered in each types of SGLT2I. The results were consistent on competing risk and other propensity score approaches analyses.

Conclusions

SGLT2I use was associated with lower risks of new gout diagnosis compared to DPP4I use.

Funding Acknowledgement

Type of funding sources: None.

Predictive value of neutrophil-to-lymphocyte ratio for atrial fibrillation and stroke in type 2 diabetes mellitus: a population-based cohort study

Introduction

Neutrophil-to-lymphocyte ratio (NLR) is a routinely available biomarker that reflects systemic inflammation. The study evaluated the predictive value of NLR for ischemic stroke and atrial fibrillation (AF) in patients with type 2 diabetes mellitus.

Methods

This was a population-based cohort study of patients with type 2 diabetes mellitus and complete blood count tests at baseline between January 1st, 2009 to December 31st, 2009 at government-funded hospitals/clinics in Hong Kong. Follow-up was until December 31st, 2019 or death.

Results

A total of 85351 patients (age=67.6±13.2 years old, male=48.8%, follow-up=3101±1441 days) were included. Univariable Cox regression found that increased NLR at quartiles 2, 3 and 4 was significantly associated with higher risks of new onset ischemic stroke (HR: 1.28 [1.20–1.37], P&lt;0.001, HR: 1.41 [1.32–1.51], P&lt;0.001 and HR: 1.38 [1.29–1.47], P&lt;0.001) and AF (hazard ratio [HR]: 1.09 [1.02–1.17], P&lt;0.015; HR: 1.28 [1.20–1.37], P&lt;0.001; HR: 1.39 [1.31–1.49], P&lt;0.001) compared to quartile 1. On multivariable analysis, NLR remained a significant predictor of ischemic stroke risk for quartiles 2 and 3 (quartile 2: HR: 1.14 [1.05, 1.22], p=0.001; quartile 3: HR: 1.14 [1.06, 1.23], p&lt;0.001) but not quartile 4 (HR: 1.08 [0.994, 1.17], p=0.070). By contrast, NLR was not predictive of AF after adjusting for confounders (quartile 2: HR: 0.966 [0.874, 1.07], p=0.499; quartile 3: HR: 0.978 [0.884, 1.08], p=0.661; quartile 4: HR: 1.05 [0.935, 1.16], p=0.462).

Conclusion

NLR is a significant predictor of new onset ischaemic stroke but not AF after adjusting for significant confounders.

Funding Acknowledgement

Type of funding sources: None.

Thrombocytopenia following implantation of different types of bioprosthetic aortic valves in severe aortic valve stenosis replacement

Aim

The use of bioprosthetic valves in the surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) of severe aortic stenosis has been associated with post-implantation thrombocytopenia, usually reversible and rarely combined with severe bleeding events. The purpose of this study was to compare the grade of thrombocytopenia and the presence of bleeding events following the implantation of bioprosthetic valves, where either surgery (Solo, Perceval, Trifecta) or transcatheter method (self-expandable TAVI) was followed.

Methods

89 patients with severe aortic stenosis were included in the study. All patients underwent either SAVR or TAVI. In each group 3 different types of bioprosthetic valves were used [59 patients in SAVR group: Solo (14), Perceval (27), Trifecta (18), 30 patients in TAVI group: Evolut R (10), Portico (15), Acurate (5)]. All patients had normal or slightly reduced platelet count at baseline. Patients previously receiving anticoagulants, patients with a primary blood disorder affecting the number of platelets, as well as patients with a post-surgery complication that could affect the number of platelets (e.g., HIT syndrome, etc.) were excluded from the study. Blood samples were taken in the morning before intervention and every morning during the first week of follow-up. Platelet count values before and after implantation were compared with paired t-test (SPSS V21.0, Inc., Chicago, IL, USA), while the reduction of platelets was compared between the 4 different valves with independent t-test. P-values of &lt;0.05 were considered significant.

Results

Mean age was 76.8±5.1 years. There was no statistically significant difference between the 2 groups of patients concerning the baseline characteristics and the administered anticoagulants. Statistically significant reduction of the blood count was observed in all groups [Solo: 136±80x103/μl (p=0.009), Perceval: 129±75x103/μl (p&lt;0.001), Trifecta: 74±32x103/μl (p&lt;0.001, TAVI: 60±103μl)]. There was no observed statistically significant difference between Solo and Perceval group (p=0.85) or Solo and Trifecta group (p=0.053), but in the case of Perceval and Trifecta group, a statistically significant difference was noted (p=0.047). A statistically significant difference in both SAVR and TAVI groups was demonstrated (p=0.040) regarding blood count reduction. There was no occurrence of any major bleeding events. 3 patients (3.3%) presented mild bleeding disorders (1 patient epistaxis and 2 patients mild hematuria).

Conclusion

Both methods, surgical and transcatheter severe aortic stenosis replacement and all the different bioprosthetic valves that were implanted, were associated with statistically significant reduction of platelet count post-implantation. This reduction was linked to the procedure due to endothelial damage, shear stress injury, inflammation-related platelet consumption, and was not associated with clinically significant bleeding events.

Funding Acknowledgement

Type of funding sources: None.

Heart rate variability and meditation: a meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Meditation can induce changes in autonomic balance, which can benefit cardiovascular health. The present meta-analysis evaluated changes in heart rate variability (HRV) in meditators.

Methods

PubMed and Embase were searched for primary prospective studies using the search terms ‘heart rate variability’ and ‘meditation’ until January 18th, 2019. The statistical significance of the difference between subgroups is evaluated by the standardized mean difference (SMD), 95% confidence interval (CI), and P-value. I2 value was used to assess the statistical heterogeneity between the included studies.

Results

Twenty-one studies involving 538 meditators (experienced= 209, beginners= 329) and 334 controls (mean age= 40.61, 35% male) were included. Regarding time-domain indices, no statistically significant differences were observed when assessing HRV between i) meditators versus controls (SMD= -0.17; 95% CI: [-0.50, 0.17]; p= 0.30; I2= 0%), ii) pre- versus post-meditation (SMD= -0.41; 95% CI: [-1.10, 0.28]; p= 0.25; I2= 80%) or iii) at baseline versus during meditation (SMD= -0.40; 95% CI: [-0.94, 0.14]; p= 0.14; I2= 72%). Pertaining to frequency-domain indices, analysis of low frequency (LF), normalized low frequency (LFnu) and high frequency (HF) between i) meditators versus controls, ii) at baseline versus post-meditation and iii) at baseline versus during meditation yet again did not show any variations. Seven studies assessed normalized high frequency (HFnu) at baseline versus during meditation collectively demonstrated a significantly higher HFnu during meditation in beginners with notable heterogeneity (SMD= 1.29; 95% CI: [0.09, 2.49]; p= 0.04; I2= 95). Moreover, LF/HF was evaluated by seven studies at baseline versus during meditation. Both meta-analysis (SMD= 0.76; 95% CI: [-0.17, 1.69]; p= 0.11; I2= 94%) as well as subset analysis of experienced meditators (SMD= -0.46; 95% CI: [-0.88, -0.03]; p= 0.03; I2= 0%) revealed a significantly lower LF/HF at baseline.

Conclusions

Short-term changes in HRV indices were observed during meditation, but there is limited evidence for significant long-term effects.

Ivabradine: pre-clinical and clinical evidence in the setting of ventricular arrhythmias

BACKGROUND

Ivabradine, an agent lowering the heart rate, acting as a funny current (If) specific inhibitor, is responsible for the sinoatrial node's spontaneous depolarization. According to current guidelines, it is indicated in specific heart failure populations and as a second-line treatment option to improve angina in chronic coronary syndromes.

REVIEW OF LITERATURE

The role of ivabradine in the setting of ventricular arrhythmias has been studied in both experimental and clinical studies. Specifically, experimental studies have examined the role of ivabradine in acute myocardial ischemia, reperfusion, digitalis-induced ventricular arrhythmias, and catecholaminergic polymorphic ventricular tachycardia showing promising results. In addition, clinical studies have shown a beneficial role of ivabradine in reducing ventricular arrhythmias. Ivabradine reduced premature ventricular contractions in combination with beta-blockers in dilated cardiomyopathy patients. Similarly, in catecholaminergic polymorphic ventricular tachycardia, ivabradine reduced dobutamine-induced premature ventricular complexes and improved ventricular arrhythmias burden. On the other hand, current data show no beneficial role of ivabradine in reducing ventricular arrhythmias in myocardial ischemia.

CONCLUSIONS

Randomized clinical trials are needed to elucidate the role of ivabradine in reducing the burden of ventricular arrhythmias in various clinical settings. HIPPOKRATIA 2022, 26 (2):49-54.

Programmed Cell Death 1 (PD-1) and Programmed Cell Death Ligand 1 (PD-L1) inhibitors and adverse cardiovascular events: a population-based study

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Cardiovascular Analytics Group

Background

Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) inhibitors are major classes of immune checkpoint inhibitors that are increasingly used for cancer treatment. However, they are associated with adverse cardiovascular events.

Purpose

To evaluate the cardiotoxicity of PD-1 and PD-L1 inhibitors, the present study aims to examine the incidence of new-onset cardiac complications in patients receiving PD-1 or PD-L1 inhibitors.

Methods

Patients receiving PD-1 or PD-L1 inhibitors since their launch up to December 31st, 2019 without pre-existing cardiac complications were included. Patient data were obtained using a territory-wide electronic health record database. The primary outcome was a composite of incident heart failure (HF), acute myocardial infarction (AMI), atrial fibrillation (AF) or atrial flutter followed up to August 31st, 2020. Propensity score matching between PD-L1 and PD-1 inhibitor use with a 1:1 ratio for patient demographics and comorbidities was performed.

Results

A total of 1925 patients were included. Over a median follow-up of 136 days (interquartile range [IQR]: 42-279), 318 (16.51%) patients met the primary outcome after PD-1/PD-L1 treatment: 242 (incidence rate [IR]: 12.57%) with HF, 38 (IR: 1.97%) with AMI, 53 (IR: 2.75%) with AF, 6 (IR: 0.31%) with atrial flutter. Compared with PD-1 inhibitor treatment, PD-L1 inhibitor treatment was significantly associated with a lower risk of composite outcome after matching (HR: 0.78, 95% CI: [0.62-0.99], P value = 0.0417). Patients who developed cardiovascular complications had shorter average readmission intervals and more hospitalization episodes after treatment with PD-1/PD-L1 inhibitors both before and after matching (P value &lt; 0.0001).

Conclusions

Compared with PD-1 inhibitor users, PD-L1 inhibitor users had a significantly lower risk of new-onset composite cardiovascular complications. Abstract Figure. Kaplan-Meier survival curve

Clustering analysis based on automated electrocardiographic measurements to identify prognostically distinct phenotypes in patients hospitalized for heart failure: a retrospective cohort study

Funding Acknowledgements

Type of funding sources: None.

Background

Heart failure (HF) is a heterogeneous disease with complex structural and electrophysiological derangements of the heart. Attempts to classify HF from the electrophysiological perspective are lacking.

Purpose

To use electrocardiographic (ECG) data for phenotypic classification of patients with HF.

Methods

In this retrospective cohort study, all adult patients hospitalized for HF during 2010-2016 at a tertiary center were included. Automated measurements of the first ECG obtained during the index admission were recorded. K-means clustering using premorbid conditions and selected ECG measurements were used to classify the cohort into four mutually exclusive clusters. The primary (all-cause and cardiovascular mortality) and secondary (ventricular arrhythmia (VA)) outcomes were compared between clusters using Cox regression analysis.

Results

In total, 2849 patients (1363 males, age 75.1 ± 13.4 years) were included. Over a mean follow-up period of 5.37 ± 4.10 years, all-cause and cardiovascular mortality occurred in 2071 (72.7%) and 600 (21.1%) patients respectively, while VA occurred in 110 patients (3.9%). Cluster 1 was characterised by a low heart rate and low ventricular activation time (VAT). Cluster 2 was characterised by old age, low absolute QRS area, and high QTc and QT dispersion. Cluster 3 was characterised by young age, and left ventricular hypertrophy (LVH), and few had history of VA. Cluster 4 was characterised by wide QRS, hypertension, ischaemic heart disease, high VAT, and high absolute T wave area. Cluster 4 had the highest and cluster 1 the lowest risks of all-cause (hazard ratio (HR) 2.96 [1.09, 1.50], p = 0.003; Figure A) and cardiovascular mortality (HR 2.90 [1.15, 2.11], p = 0.004; Figure B). Meanwhile, cluster 2 had the highest risk of VA (HR 2.23 [1.09, 3.85], p = 0.025; Figure C) while clusters 1 and 3 similarly had the lowest risks.

Conclusion

HF presents with clinically and electrophysiologically distinct phenotypes. Clustering analysis is useful in identifying HF phenotypes which are prognostically significant. Abstract Figures A, B, and C

Virtual medical research mentoring and collaboration: breaking the bounds of nationality during the COVID-19 pandemic

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Cardioovascular Analytics Group

Background

Medical research is critical to professional advancement, and mentoring is an important means of early research engagement in medical training. In contrast to international research collaborations, research mentoring programs are often locally limited. With the COVID-19 pandemic causing drifts to virtual classes and conferences, virtual international medical research mentoring may be viable. We hereby describe our experience with a virtual, international mentorship group for cardiovascular research.

Methods

Our virtual international research mentorship group has been running since 2015. The group focuses on risk stratification and outcomes research in cardiovascular medicine and epidemiology. Mentees from any country or region in all stages of medical careers are welcomed. Considering the increasing emphasis of contemporary research on multidisciplinary healthcare and translational research, our team also includes allied healthcare professionals or students, and graduates from natural sciences (Figure 1). With our members’ diverse backgrounds, we firmly adhere to the principle that all members must be given equal opportunities and treatment, regardless of their age, gender, race, nationality, sexual orientation, family background, and institution of study or practice. We make use of virtual platforms and multi-level mentoring (both senior and peer mentoring), and emphasize active participation, early leadership, open culture, accessible research support, and a distributed research workflow (i.e. an accessible-distributed model).

Results

Since establishment, our group has expanded to include 63 active members from 14 countries (Figure 2), leading a total of 109 peer-reviewed original studies and reviews published. We observed no significant difficulty in communication between team members, nor conflicts due to differences in nationality or ethnicity. Most studies involve cross-country and ethnicity collaborations, and inter-disciplinary and inter-regional knowledge exchanges are frequent. Multi-level mentoring ensured mentoring quality without compromising bonding and communication.

Conclusion

An accessible-distributed model of virtual international medical research collaboration and multi-level mentoring is viable, efficient, and caters to the needs of contemporary healthcare. We hope that others will build similar models and improve medical research mentoring globally.

Paediatric/young versus adult patients with congenital long QT syndrome or catecholaminergic polymorphic ventricular tachycardia

Introduction

Congenital long QT syndrome (LQTS) and catecholaminergic ventricular tachycardia (CPVT) are less prevalent cardiac ion channelopathies than Brugada syndrome in Asia. The present study compared paediatric/young and adult patients with these conditions.

Method

This was a territory-wide retrospective cohort study of consecutive patients diagnosed with congenital LQTS and CPVT attending public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).

Results

A total of 142 congenital LQTS (mean onset age= 27±23 years old) and 16 CPVT (mean presentation age=11±4 years old) patients were included. For congenital LQTS, arrhythmias other than VT/VF (HR=4.67, 95% confidence interval = [1.53–14.3], p=0.007), initial VT/VF (HR=3.25 [1.29–8.16], p=0.012) and Schwartz score (HR=1.90 [1.11–3.26], p=0.020) were predictive of the primary outcome for the overall cohort, whilst arrhythmias other than VT/VF (HR=5.41 [1.36–21.4], p=0.016) and Schwartz score (HR=4.67 [1.48–14.7], p=0.009) were predictive for the adult subgroup (&gt;25 years old; n=58). All CPVT patients presented before the age of 25 but no significant predictors of VT/VF were identified. A random survival forest model identified initial VT/VF, Schwartz score, initial QTc interval, family history of LQTS, initially asymptomatic, and arrhythmias other than VT/VF as the most important variables for risk prediction in LQTS, and initial VT/VF/sudden cardiac death, palpitations, QTc, initially symptomatic and heart rate in CPVT.

Conclusion

Clinical and ECG presentation vary between the pediatric/young and adult congenital LQTS population. All CPVT patients presented before the age of 25. Machine learning models achieved more accurate VT/VF prediction.

Funding Acknowledgement

Type of funding sources: None. Kaplan-Meier survival curve for LQTSKaplan-Meier survival curve for CPVT

Transcriptional profiles of genes related to electrophysiological function in scn5a+/− murine hearts

Background

The Scn5a gene encodes the major pore-forming Nav1.5 (α) subunit, of the voltage-gated Na+ channel in cardiomyocytes. The key role of Nav1.5 in action potential initiation and propagation in both atria and ventricles predisposes organisms lacking Scn5a or carrying Scn5a mutations to cardiac arrhythmogenesis. Loss-of-function Nav1.5 genetic abnormalities account for many cases of the human arrhythmic disorder Brugada Syndrome (BrS) and related conduction disorders. A murine model with a heterozygous Scn5a deletion recapitulates many electrophysiological phenotypes of BrS.

Purpose

This study examines relationships between its Scn5a+/− genotype, resulting transcriptional changes and the consequent phenotypic presentations of BrS.

Methods

Atrial and ventricular tissue samples were obtained from aged (11±3 months) wild-type (WT) and homozygous Scn5a+/− mice. Quantitative PCR was used to examine transcription of 60 genes underlying cardiac tissue excitability.

Results

Of selected protein-coding genes related to cardiomyocyte electrophysiological or homeostatic function, concentrations of mRNA transcribed from 15 differed significantly from WT. Despite halved apparent ventricular Scn5a transcription heterozygous deletion did not significantly downregulate its atrial expression, raising possibilities of atria-specific feedback mechanisms. Most of the remaining 14 genes whose expression differed significantly between WT and Scn5a+/− animals involved Ca2+homeostasis specifically in atrial tissue, with no overlap with any ventricular changes. All significant differences shown by the atria and ventricles were up- and downregulations, respectively.

Conclusion

This investigation demonstrates the value of future experiments exploring for and clarifying links between transcriptional control of Scn5a and of genes whose protein products coordinate Ca2+ regulation and examining their possible roles in BrS.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University of Surrey; Medical Research Council

Derivation of an electronic frailty index for short-term mortality in heart failure: a machine learning approach

Objective

Frailty may be found in heart failure patients especially in the elderly and is associated with a poor prognosis. However, assessment of frailty status is time-consuming and the electronic frailty indices developed using health records have served as useful surrogates. We hypothesized that an electronic frailty index developed using machine learning can improve short-term mortality prediction in patients with heart failure.

Methods

This was a retrospective observational study included patients admitted to nine public hospitals for heart failure from Hong Kong between 2013 and 2017. Age, sex, variables in the modified frailty index, Deyo's Charlson comorbidity index (≥2), neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI) were analyzed. Gradient boosting, which is a supervised sequential ensemble learning algorithm with weak prediction submodels (typically decision trees), was applied to predict mortality. Variables were ranked in the order of importance with a total score of 100 and used to build the predictive models. Comparisons were made with decision tree and multivariate logistic regression.

Results

A total of 8893 patients (median: age 81, Q1-Q3: 71–87 years old) were included, in whom 9% had 30-day mortality and 17% had 90-day mortality. PNI, age and NLR were the most important variables predicting 30-day mortality (importance score: 37.4, 32.1, 20.5, respectively) and 90-day mortality (importance score: 35.3, 36.3, 14.6, respectively). Gradient boosting significantly outperformed decision tree and multivariate logistic regression (area under the curve: 0.90, 0.86 and 0.86 for 30-day mortality; 0.92, 0.89 and 0.86 for 90-day mortality).

Conclusions

The electronic frailty index based on comorbidities, inflammation and nutrition information can readily predict mortality outcomes. Their predictive performances were significantly improved by gradient boosting techniques.

Funding Acknowledgement

Type of funding sources: None.

A territory-wide study of arrhythmogenic right ventricular cardiomyopathy patients from Hong Kong

Background

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a hereditary disease characterised by fibrofatty infiltration of the right ventricular myocardium that predisposes affected patients to malignant ventricular arrhythmias, dual-chamber cardiac failure and sudden cardiac death (SCD).

Methods

This was a territory-wide retrospective cohort study of patients diagnosed with ARVC/D between 1997 and 2019. The primary outcome was incident ventricular tachycardia/ventricular fibrillation (VT/VF). The secondary outcomes were new-onset heart failure with reduced ejection fraction (HFrEF) and all-cause mortality.

Results

This study consisted of 115 ARVC/D patients (median age: 60 [44.1–70.2] years; 58% male). Of these, 51 and 24 patients developed incident VT/VF and new-onset HFrEF, respectively. Five patients underwent cardiac transplantation, and 14 died during follow-up. Multivariate Cox regression identified prolonged QRS duration as a predictor of VT/VF (P&lt;0.05). Female gender, prolonged QTc duration, the presence of epsilon waves and T-wave inversion (TWI) in any lead except aVR/V1 predicted new-onset HFrEF (P&lt;0.05). Female gender, prolonged QTc duration and the presence of epsilon waves, in addition to the parameters of older age at diagnosis of ARVC/D, prolonged QRS duration and worsening ejection fraction predicted all-cause mortality (p&lt;0.05). Clinical scores were also developed to predict new-onset HFrEF (Table 1a-c) and all-cause mortality (Table 2a-c). This was followed by the application of a non-parametric machine learning survival analysis models for outcome prediction. These machine learning algorithms better capture nonlinear and interactive patterns within survival data compared to traditionally used Cox regression models, which assume the existence of a hazard function between survival data and censored outcomes. The present study introduced weighted random survival forests models for the prediction of incident VT/VF, HFrEF and all-cause mortality. Findings indicate that these machine learning wRSF models performed the best in the prediction of all three aforementioned outcomes compared to other analytical methods.

Conclusion

Clinical and electrocardiographic parameters are important for assessing prognosis in ARVC/D patients. Machine learning algorithms appear to be the most optimal tools for event prediction, and as such should potentially be used to aid risk stratification and decision-making in the clinical setting.

Funding Acknowledgement

Type of funding sources: None.

Brugada syndrome in Hong Kong: long term outcome prediction through machine learning

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Brugada syndrome (BrS) is an ion channelopathy that predisposes affected patients to spontaneous ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death (SCD). Despite its greater prevalence in Asia and epidemiological heterogeneity in disease manifestation, the majority of the conducted cohort studies available in current literature are based in Western countries. 

Purpose

The aim of this study is to examine the clinical and electrocardiographic predictive factors of spontaneous VT/VF for Asian BrS patients.

Methods

This was a territory-wide retrospective cohort study of patients diagnosed with BrS between 1997 and 2019. The primary outcome was spontaneous VT/VF detected either during hospital admission or by implantable-cardioverter defibrillator (ICD) data. Cox regression was used to identify significant clinical and electrocardiographic risk predictors. Non-linear interactions between variables (latent patterns) were extracted using non-negative matrix factorization (NMF) and used as inputs into the random survival forest (RSF) model.

Results

This study included 516 consecutive BrS patients (mean age of initial presentation= 50 ± 16 years, male= 92%) with a median follow-up of 86 (interquartile range: 45-118) months. The cohort was divided into subgroups based on initial disease manifestation: asymptomatic (n = 314), syncope (n = 159) or VT/VF (n = 41). Annualized event rates per person-year were 1.70%, 0.05% and 0.01% for the VT/VF, syncope and asymptomatic subgroups, respectively. Multivariate Cox regression analysis revealed initial presentation of VT/VF (HR = 24.0, 95% CI = [1.21, 479] , P= 0.037) and standard deviation of P-wave duration (HR = 1.07, 95% CI = [1.00, 1.13], P = 0.044) were significant predictors. The NMF-RSF showed the best predictive performance compared to RSF and Cox regression models (precision: 0.87 v.s. 0.83 v.s. 0.76, recall: 0.89 v.s. 0.85 v.s. 0.73, F1-score: 0.88 v.s. 0.84 v.s. 0.74).

Conclusions

This is one of the largest territory-wide cohort studies on BrS and the largest study in Asia published to date, with an extensive median follow-up duration of 7 years. Clinical history, electrocardiographic markers and investigation results provide important information for risk stratification. Machine learning techniques using NMF and RSF significantly improves overall risk stratification performance.

IP3R1/GRP75/VDAC1 complex mediated endoplasmic reticulum stress-mitochondrial oxidative stress in diabetic atrial remodeling

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): National Natural Science Foundation of China

Background

Mitochondrial oxidative stress is an important mechanism of atrial remodeling and atrial fibrillation (AF) in the setting of diabetes. Currently, endoplasmic reticulum (ER) stress is regarded as the key link from homeostasis to dysfunction, and is a central feature of metabolic diseases such as type 2 diabetes. However, the molecular mechanisms underlying these processes have not been fully elucidated.

Objective

To explore the potential role of ER stress-mitochondrial oxidative stress in atrial remodeling and AF induction in diabetes.

Methods

 Mouse atrial cardiomyocytes (HL-1 cells) , type 2 diabetic rats and GRP75 conditional knockout mice were used as models systems. These findings were correlated with biomarker findings in human diabetic patients with confirmed atrial fibrillation.

Results

 In the diabetic rat atria, significant ER stress was observed. Treatment with tunicamycin (TM), an ER stress agonist, mass spectrometry (MS) demonstrated many known ER stress and calmodulin proteins, including Heat shock protein family A (Hsp70) member (Hspa) 5 (GRP78) and Hspa9 (GRP75) and in situ proximity ligation assay (PLA) indicated that TM led to increased protein expression of the IP3R1 (inositol 1,4,5-trisphosphate receptors 1)/GRP75 (glucose-regulated protein 75)/VDAC1 (voltage-dependent anion channel 1) complex in HL-1 cells. Silencing of GRP75 using siRNA in HL-1 cells and GRP75 conditional knockout in our mouse model led to impaired calcium transport from the ER to mitochondria, and alleviated mitochondrial oxidative stress and calcium overload. Moreover, GRP75 deficiency attenuates atrial remodeling and AF progression in Myh6-Cre+/Hspa9flox/flox + TM mice.

Conclusions

 The IP3R1/GRP75/VDAC1 complex mediates endoplasmic reticulum stress-mitochondrial oxidative stress plays an important role in diabetic atrial remodeling. Abstract Figure

Risk stratification score for acute myocardial infarction and sudden cardiac death in type 2 diabetes mellitus

Funding Acknowledgements

Type of funding sources: None.

Introduction

Acute myocardial infarction (AMI) and sudden cardiac death (SCD) are major cardiovascular adverse outcomes in patients with type 2 diabetic mellitus. Although there are many risk scores on composite outcomes of major cardiovascular adverse outcomes or cardiovascular mortality for diabetic patients, these existing scores did not account for the difference in pathogenesis and prognosis between acute coronary syndrome and lethal ventricular arrhythmias. Furthermore, recent studies reported that HbA1c and lipid levels, which were often accounted for in these risk scores, have J/U-shaped relationships with adverse outcomes.

Purpose

The present study aims to evaluate the application of incorporating non-linear J/U-shaped relationships between mean HbA1c and cholesterol levels into risk scores for predicting for AMI and non-AMI related SCD respectively, amongst type 2 diabetes mellitus patients.

Methods

This was a territory-wide cohort study of patients with type 2 diabetes mellitus above the age 40 and free from prior AMI and SCD, with or without prescriptions of anti-diabetic agents between January 1st, 2009 to December 31st, 2009 at government-funded hospitals and clinics in Hong Kong. Risk scores were developed for predicting incident AMI and non-AMI related SCD. The performance of conditional inference survival forest (CISF) model compared to that of random survival forests (RSF) model and multivariate Cox model.

Results

This study included 261308 patients (age = 66.0 ± 11.8 years old, male = 47.6%, follow-up duration = 3552 ± 1201 days, diabetes duration = 4.77 ± 2.29 years). Mean HbA1c and high-density lipoprotein-cholesterol (HDL-C) were significant predictors of AMI under multivariate Cox regression and were linearly associated with AMI. Mean HbA1c and total cholesterol were significant multivariate predictors with a J-shaped relationship with non-AMI related SCD. The AMI and SCD risk scores had an area-under-the-curve (AUC) of 0.666 (95% confidence interval (CI)= [0.662, 0.669]) and 0.677 (95% CI= [0.673, 0.682]), respectively. CISF significantly improves prediction performance of both outcomes compared to RSF and multivariate Cox models.

Conclusions

A holistic combination of demographic, clinical, and laboratory indices can be used for the risk stratification of type 2 diabetic patients against AMI and SCD.

Electronic frailty index for predicting mortality outcome of patients undergoing transaortic valvular implantation

Funding Acknowledgements

Type of funding sources: None.

Objective

Electronic frailty index for predicting mortality outcome of patients undergoing transaortic valvular implantation (TAVI) served as useful surrogates but is associated with a poor prognosis since it needs long time to determine the frailty status and develop the index based on electronic health records. We identify significant risk mortality predictors and tested the hypothesis that an electronic frailty index incorporating ECG measurements and laboratory examinations using a machine learning survival analysis approach can improve TAVI mortality prediction.

Design

A territory-wide observational study which involved a total of 450 patients (49.11% females, 22 mortalities) diagnosed undergoing TAVI and admitted to public hospitals from Hong Kong.

Methods

Demographics (TAVI presentation age, gender, severity of TR, AR, MR, PR, INR of TAVI presentation), prior comorbidities before TAVI presentation, ECG measurements, and CBC and LRFT laboratory examinations were analyzed. Cox regression and a supervised sequential ensemble learning algorithm: gradient boosting survival tree (GBST) model, was applied to predict mortality. Significant univariate and multivariate risk predictors of mortality were identified. Importance ranking of variables were obtained with GBST model and used to build the frailty models. Comparisons were provided with baseline models of random survival forests and multivariate Cox regression.

Results

The median TAVI presentation age was 82.3 years (83.8 years in mortalities, and 82.1 years in alive patients). INR of TAVI presentation in mortalities (median: 1.32) is much higher than alive ones (median: 1.07). Severe TR (hazard ratio, HR: 8.93, 95% CI: [3.22, 24.78], p value &lt; 0.0001), INR of TAVI presentation (HR: 2.74, 95% CI: [1.84, 4.09], p value &lt; 0.0001), cumulative hospital stays (HR: 1.01, 95% CI: [1.00, 1.01], p value = 0.0008), aspartate transaminase (HR: 1.01, 95% CI: [0.98, 1.002], p value = 0.0002), and bilirubin (HR: 1.02, 95% CI: [1.01, 1.02], p value = 0.0003) are significant mortality risk predictors. Machine learning survival analysis model found that APTT demonstrates the most important strength, followed by INR of TAVI presentation, severe TR status, cumulative hospital stays, cumulative readmission times, creatinine test, urate test ALP test, and ECG measurements of QTc and QT. GBST significantly outperformed random survival forests and multivariate Cox regression (precision: 0.91, recall: 0.89, AUC: 0.93, C-index: 0.96, and KS-index: 0.50) for mortality prediction.

Conclusions

 Electronic frailty index based on demographics, prior comorbidities, hospitalization characteristics, ECG measurements, and laboratory examinations can efficiently predict mortality outcome of patients undergoing TAVI. Machine learning survival learning model significantly improves the risk prediction performance and improves the construction of the frailty models for tailored interventions of TAVI patients in clinical practices.

Echocardiography update for primary care physicians: a review

Echocardiography is a key evaluation tool for the diagnosis, prognosis, and guidance of interventional management of numerous cardiovascular conditions, including ischaemia, heart failure, and structural heart diseases. Recent technological advancements have also seen the exploration of artificial intelligence, intracardiac vortex imaging, and three-dimensional printing in echocardiography. With cardiovascular diseases increasing in prevalence worldwide, it is important for clinicians including general practitioners to have updated knowledge of appropriate use of echocardiography. As such, this article reviews the current literature and summarises the latest developments and the general clinical usage of echocardiography.

P5438Cardiac abnormalities after induction of endoplasmic reticulum stress are associated with mitochondrial dysfunction and connexin43 expression

Background

The endoplasmic reticulum (ER) is responsible for protein synthesis and calcium storage. ER stress, reflected by protein unfolding and calcium handling abnormalities, has been studied as a pathogenetic factor in cardiovascular diseases.

Purpose

The aim of this study is to examine the effects of ER stress on mechanical and electrophysiological functions in the heart and explore the underlying molecular mechanisms.

Methods

A total of 30 rats were randomly divided into control, ER stress induction (tunicamycin) and ER stress inhibition (4-phenylbutyric acid, 4-PBA) groups.

Results

ER stress induction led to significantly systolic and diastolic dysfunction as reflected by maximal increasing/decreasing rate of left intraventricular pressure (±dp/dt), LV peak systolic pressure, LV development pressure and LV end-diastolic pressure. Epicardial electrical mapping performed in vivo revealed reduced conduction velocity, increased conduction heterogeneity and spontaneous ventricular tachycardia. Masson's trichrome staining revealed marked fibrosis in the myocardial interstitium and sub-pericardium and thickened epicardium. Western blot analysis revealed increased pro-fibrotic factor TGF-β1, decreased mitochondrial biogenesis protein PGC-1a, decreased mitochondrial fusion protein MFN2. These changes were associated with decreased mitochondrial membrane potential (MMP) and connexin 43 translocation to mitochondria. These abnormalities can be partially prevented by the ER stress inhibitor 4-PBA.

Conclusions

Our study shows that ER stress induction can produce cardiac electrical and mechanism dysfunction as well as structural remodeling. Mitochondrial function alterations are contributed by CX43 transposition to mitochondria. These abnormalities can be partially prevented by the ER stress inhibitor 4-PBA.

Acknowledgement/Funding

National Natural Science Foundation of China (No. 81570298 to T.L.)

P5014The NPAC score for predicting survival after incident acute myocardial infarction

Background

Risk stratification in acute myocardial infarction (AMI) is important for guiding clinical management. Current risk scores are mostly derived from clinical trials with stringent patient selection. We aimed to establish and evaluate a composite scoring system to predict short-term mortality after index episodes of AMI, independent of electrocardiography (ECG) pattern, in a large real-world cohort.

Methods

Using electronic health records, patients admitted to our regional teaching hospital (derivation cohort, n=2127) and an independent tertiary care center (validation cohort, n=1276) with index acute myocardial infarction between January 2013 and December 2017 as confirmed by principal diagnosis and laboratory findings, were identified retrospectively.

Results

Univariate logistic regression was used as the primary model to identify potential contributors to mortality. Stepwise forward likelihood ratio logistic regression revealed that neutrophil-to-lymphocyte ratio, peripheral vascular disease, age, and serum creatinine (NPAC) were significant predictors for 90-day mortality (Hosmer-Lemeshow test, P=0.21). Each component of the NPAC score was weighted by beta-coefficients in multivariate analysis. The C-statistic of the NPAC score was 0.75, which was higher than the conventional Charlson's score (C-statistic=0.63). Application of a deep learning model to our dataset improved the accuracy of classification with a C-statistic of 0.81.

Multivariate binary logistic regression Variable β Adjusted Odds ratio (95% CI) P-value Points Age ≥65 years 1.304 3.68 (2.63–5.17) <0.001 2 Peripheral vascular disease 1.109 3.03 (1.52–6.04) 0.002 2 NLRt ≥9.51 1.100 2.73 (2.12–3.51) <0.001 1 Creatinine≥109 μmol/L 1.003 3.00 (2.35–3.85) <0.001 2

NPAC deep learning model

Conclusions

The NPAC score comprised of four items from routine laboratory parameters and basic clinical information and can facilitate early identification of cases at risk of short-term mortality following index myocardial infarction. Deep learning model can serve as a gate-keeper to provide more accurate prediction to facilitate clinical decision making.

P6597Long-term impact of catheter ablation on growth differentiation factor-15 and neutrophil-lymphocyte ratio in paroxysmal atrial fibrillation

Background

There is increasing evidence that inflammatory biomarkers growth differentiation factor 15 (GDF-15) and neutrophil-lymphocyte ratio (NLR) appear to be associated with stroke and adverse cardiovascular events in patients with atrial fibrillation (AF). However, long-term impact of catheter ablation (CA) on GDF-15 and NLR is still unknown.

Objective

To evaluate the long-term change in GDF-15 and NLR after CA in paroxysmal AF patients.

Methods

A total of 58 paroxysmal AF patients were consecutively enrolled to perform CA. The inflammatory biomarkers GDF-15 and NLR were measured at baseline and 6-months postablation.

Results

All patients except one could complete 6-Months follow up. Fifty (87.7%) patients maintained sinus rhythm (SR group) and seven (12.3%) patients sustained AF recurrence (AFR group). No significant difference was noted in clinical and procedural characteristics between two groups (p>0.05), except mean fluoroscopy time (minutes 22±11.7 vs. 13±5.3, p=0.001) significantly longer in AFR than SR group. The GDF-15 (pg/ml 195±57 vs. 216±88, p=0.398), and NLR (% 1.8 (1.3–3) vs. 2.6 (1.4–3.4), p=0.395) were comparable at baseline in both SR and AFR groups respectively. At 6-months postablation, GDF-15 (pg/ml 133±41 vs. 195±57, p<0.001), and NLR (% 1.6 (1.1–2) vs. 1.8 (1.3–3), p=0.004) were significant deceased compared to baseline levels in SR group. However, GDF-15 (pg/ml 139±86 vs. 216±88, p=0.064), and NLR (% 1.6 (1.2–3) vs. 2.6 (1.4–3.4), p=0.398) biomarkers remained comparable to baseline level in AFR group (p>0.05)

Conclusion

Inflammatory biomarkers; GDF-15 and NLR significantly decreased at long-term on successful maintenance of sinus rhythm by CA in paroxysmal AF patients.

Acknowledgement/Funding

None

P1890Pioglitazone inhibits diabetes-induced atrial mitochondrial oxidative stress and improves mitochondrial biogenesis, dynamics and function through the PGC-1 signaling pathway

Background

Oxidative stress contributes to adverse atrial remodeling in diabetes mellitus. This can be prevented by the PPAR-γ agonist pioglitazone through its anti-oxidant and anti-inflammatory effects.

Purpose

In this study, the molecular mechanisms underlying these effects were investigated.

Methods

Rabbits were randomly divided into control (C), diabetic (DM), and pioglitazone-treated DM (Pio) groups. Echocardiographic, hemodynamic, electrophysiological, intracellular Ca2+ properties were measured. Serum PPAR-γ levels, serum and tissue oxidative stress and inflammatory markers, mitochondrial morphology, reactive oxygen species (ROS) production rate, respiratory function, and mitochondrial membrane potential (MMP) levels were measured. Protein expression of pro-fibrotic marker transforming growth factor β1 (TGF-β1), and the mitochondrial proteins (PGC-1α, fission and fusion-related proteins) were measured.

Results

Compared with controls, the DM group demonstrated larger left atrial diameter and fibrosis area associated with a higher incidence of inducible AF. Lower serum PPAR-γ level was associated with lower PGC-1α, higher NF-κB and higher TGF-β1 expression. Mn-SOD protein was not different but lower mitochondrial fission- and fusion-related proteins were detected. Mitochondrial swelling, higher mitochondrial ROS, lower respiratory control rate, lower MMP and higher intracellular Ca2+ transients were observed. In the Pio group, reversal of structural remodeling and lower inducible AF incidence were associated with higher PPAR-γ and PGC-1α. NF-κB and TGF-β1 were lower and biogenesis, fission and fusion-related protein were higher. Mitochondrial structure and function, and intracellular Ca2+ transients were improved. In HL-1 cell line, transfected with PGC-1α siRNA blunted the effect of pioglitazone on Mn-SOD protein expression and MMP collapse in H2O2-treated cells.

Conclusion

Diabetes mellitus induces adverse atrial structural and electrophysiological remodeling, abnormal Ca2+ handling and mitochondrial damage and dysfunction. Pioglitazone prevented these abnormalities through the PPAR-γ/PGC-1α pathway.

Acknowledgement/Funding

National Natural Science Foundation of China (No 81570298, 81270245, 30900618 to T.L.)

P2838The impact of anesthesia depth on catheter ablation for atrial fibrillation: a systematic review and meta-analysis of observational studies

Objectives

This meta-analysis and systematic review seeks to compare both characteristic parameters and procedural outcomes of catheter ablation in patients under GA/deep sedation and mild/moderate sedation.

Background

Catheter ablation has become a widely applied intervention for treating symptomatic AF and arrhythmias that are refractory to medical therapy. It can be conducted through from mild sedation to general anesthesia.

Methods

PubMed and Embase were searched up to July 2018 for randomized controlled trials, cohort and observational studies that assessed the outcomes of catheter ablation under GA/deep sedation or mild/moderate sedation. 12 studies were included in this meta-analysis after screening with the inclusion and exclusion criteria. Heterogeneity between studies and publication bias was evaluated by I2 index and Egger's regression, respectively.

Results

Our meta-analysis found catheter AF ablation with GA/deep sedation to be associated with reduced risk of recurrence (RR: 0.79, 95% CI: 0.56 to 1.13, P=0.20) and complications (RR: 0.95, 95% CI: 0.64 to 1.42, P=0.82), though statistically insignificant. In terms of procedural parameters, there was non-significant difference between the two groups when both procedural time (SMD: −0.13, 95% CI: −0.90 to 0.63, P=0.74) and fluoroscopy time (SMD: −0.41, 95% CI: −1.40 to 0.58, P=0.41) were considered. Multivariate meta-regression demonstrated hypertension as an independent moderating factor for complication risk.

Complications Comparison

Conclusion

Apart from an increased likelihood of procedural success, ablation by GA/deep sedation was found to be non-significantly different from the mild/moderate sedation approach in both procedural parameters and outcome measures.

The association of hematological indices with the response to cardiac resynchronization therapy: a single-center study

BACKGROUND

Cardiac resynchronization therapy (CRT) is an established therapeutic option for patients with heart failure (HF) and left ventricular ejection fraction (LVEF) ≤35 % who meet specific criteria according to current guidelines. However, up to 40 % of patients have no response to CRT. Our study aimed to investigate the association between different hematological and biochemical indices and response to CRT.

METHODS

Patients with HF due to ischemic or dilated cardiomyopathy referred to our hospital for CRT implantation from January 2013 to November 2017 were included in the study. Response to CRT was defined as an increase in LVEF ≥10 % or a decrease in left ventricular end-systolic volume (LVESV) ≥15 % at six months of follow-up.

RESULTS

A total of 48 patients (mean age: 66.2 ± 9.5 years, 81.3 % males) were included in the study. Of these HF patients, 29 (60.4 %) had ischemic cardiomyopathy, and 19 (39.6 %) had dilated cardiomyopathy. At six months of follow-up, 37 patients (77.1 %) had responded to CRT. Ten patients (20.8 %) had ventricular tachycardia (VT), 24 (50 %) patients were hospitalized, and two patients (4.2 %) died during the follow-up period. Multivariate analysis demonstrated that age (p =0.03) and creatinine levels (p =0.02) were independent predictors of the response to CRT. No significant associations between hematological markers (white blood cells, neutrophils, lymphocytes, platelets, neutrophil to lymphocyte ratio, red blood cells distribution width) and CRT response were observed.

CONCLUSIONS

A smaller increase in LVEF and a smaller decrease in LVESV were predictive for VT occurrence and hospitalizations in patients receiving CRT. No significant association between hematological markers and response to CRT was found. HIPPOKRATIA 2019, 23(3): 118-125.

Abstract P3-08-03: Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort

Although rare, Metaplastic Breast Carcinomas (MBC) account for significant global breast cancer mortality. This subgroup is extremely heterogeneous and by definition exhibits metaplastic change to squamous and/or mesenchymal elements, including but not limited to spindle, squamous, chondroid, osseous and rhabdomyoid elements. The WHO working group recognizes that the current classification is inadequate and in the interim, has suggested a purely descriptive classification. The mixed epithelial-mesenchymal morphology has led to speculation that MBC represent 'stem cell tumours'; in support of this, MBC have been shown to have a CD44+/CD24-/low phenotype. Clinically, patients present with tumours that are larger (higher stage), have increased likelihood of distant metastases at presentation and overall, have a reduced 5-year survival rate compared to Invasive Carcinoma-NST. Hence, this is a unique subtype with poor outcome but without a robust classification or understanding of the biology to aid clinical management. We present a detailed morphological, immunohistochemical and genomic analysis of a large series of MBC (n=347), as amassed through the Asia-Pacific MBC consortium. We consider our morphological dissection using the WHO subtyping guidelines and show that an increasing number of phenotypes in a mixed MBC (classified as WHO_1) significantly associates with a poor prognosis. Immunohistochemical analysis showed that a pure spindle (WHO_5) is significantly less likely to express vimentin, CK5/6, CK14, and CK19 than a mixed WHO_1 with spindle features. Similarly, a WHO_1 with chondroid features is less likely to express EGFR than WHO_1 with chondroid features and rhabdoid or osseous differentiation. Across the cohort, positivity for the AE1/3 antibody and a lack of EGFR expression both significantly associate with a better outcome. We report no significant association between patient age at diagnosis and breast cancer specific survival, nor between age and specific WHO MBC subtypes. We report a significant association between WHO_1 types and increasing tumour grade, and also between tumour size and grade, with tumour size being a highly significant prognostic indicator in this cohort. Our exome sequencing confirms a significant enrichment for TP53 and PTEN mutations in MBC, and intriguingly for concurrent mutations of TP53, PTEN and PIK3CA. A novel enrichment for NF1 mutations is also presented. In summary, we provide a thorough assessment of a large cohort of MBC, including morphology, survival, IHC and exome sequencing, and present our analysis contextualized by the WHO guidelines, extending the existing knowledge base of this rare tumour type.

Citation Format: McCart Reed AE, Kalaw E, Nones K, Bettington M, Lim M, Bennett J, Johnstone K, Kutasovic JR, Kazakoff S, Xu QC, Saunus JM, Reid LE, Black D, Niland C, Ferguson K, Gresshoff I, Raghavendra A, Liu JC, Kalinowski L, Reid AS, Davidson M, Pearson JV, Yamaguchi R, Harris G, Tse G, Papadimos D, Pathmanathan R, Pathmanathan N, Tan PH, Fox S, O'Toole S, Waddell N, Simpson PT, Lakhani SR. Dissecting the heterogeneity of metaplastic breast cancer: A morphological, immunohistochemical and genomic analysis of a large cohort [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 P3-08-03.

Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Heart and lung transplantation is a high-risk procedure requiring intensive immunosuppressive therapy for preventing organ rejection. Alemtuzumab, a CD52-specific monoclonal antibody, is increasingly used for induction therapy compared with conventional agents. However, there has been no systematic review comparing its efficacy with traditional therapeutic drugs.

METHODS

PubMed and EMBASE were searched to October 1, 2017, for articles on alemtuzumab in cardiothoracic transplant surgery. Of the 433 studies retrieved, 8 were included in the final meta-analysis.

RESULTS

In lung transplantation, alemtuzumab use was associated with lower odds of acute cellular rejection compared with antithymocyte globulin (odds ratio [OR], 0.21; 95% CI, 0.11-0.40; P < .001), lower acute rejection rates (OR, 0.12; 95% CI, 0.03-0.55; P < .01), and infection rates (OR, 0.69; 95% CI, 0.35-1.36; P = .33) when compared with basiliximab. Multivariate meta-regression analysis found that mean age, male sex, single lung transplant, double lung transplant, cytomegalovirus or Epstein-Barr virus status, idiopathic pulmonary fibrosis, cystic fibrosis, and mean ischemic time did not significantly influence acute rejection outcomes. For heart transplantation, alemtuzumab use was associated with lower acute rejection rates when compared with tacrolimus (OR, 0.44; 95% CI, 0.30-0.66; P < .001).

CONCLUSIONS

Alemtuzumab use was associated with lower rejection rates when compared with conventional induction therapy agents (antithymocyte globulin, basiliximab, and tacrolimus) in heart and lung transplantation. However, this was based on observational studies. Randomized controlled trials are needed to verify its clinical use.

Tuning Gene Activity by Inducible and Targeted Regulation of Gene Expression in Minimal Bacterial Cells

Functional genomics studies in minimal mycoplasma cells enable unobstructed access to some of the most fundamental processes in biology. Conventional transposon bombardment and gene knockout approaches often fail to reveal functions of genes that are essential for viability, where lethality precludes phenotypic characterization. Conditional inactivation of genes is effective for characterizing functions central to cell growth and division, but tools are limited for this purpose in mycoplasmas. Here we demonstrate systems for inducible repression of gene expression based on clustered regularly interspaced short palindromic repeats-mediated interference (CRISPRi) in Mycoplasma pneumoniae and synthetic Mycoplasma mycoides, two organisms with reduced genomes actively used in systems biology studies. In the synthetic cell, we also demonstrate inducible gene expression for the first time. Time-course data suggest rapid kinetics and reversible engagement of CRISPRi. Targeting of six selected endogenous genes with this system results in lowered transcript levels or reduced growth rates that agree with lack or shortage of data in previous transposon bombardment studies, and now produces actual cells to analyze. The ksgA gene encodes a methylase that modifies 16S rRNA, rendering it vulnerable to inhibition by the antibiotic kasugamycin. Targeting the ksgA gene with CRISPRi removes the lethal effect of kasugamycin and enables cell growth, thereby establishing specific and effective gene modulation with our system. The facile methods for conditional gene activation and inactivation in mycoplasmas open the door to systematic dissection of genetic programs at the core of cellular life.

Meta-analysis on shift work and risks of specific obesity types

AIMS

This systematic review and meta-analysis evaluated the associations between shift work patterns and risks of specific types of obesity.

METHODS

PubMed was searched until March 2017 for observational studies that examined the relationships between shift work patterns and obesity. Odds ratio for obesity was extracted using a fixed-effects or random-effects model. Subgroup meta-analyses were carried out for study design, specific obesity types and characteristics of shift work pattern.

RESULTS

A total of 28 studies were included in this meta-analysis. The overall odds ratio of night shift work was 1.23 (95% confidence interval = 1.17-1.29) for risk of obesity/overweight. Cross-sectional studies showed a higher risk of 1.26 than those with the cohort design (risk ratio = 1.10). Shift workers had a higher frequency of developing abdominal obesity (odds ratio = 1.35) than other obesity types. Permanent night workers demonstrated a 29% higher risk than rotating shift workers (odds ratio 1.43 vs. 1.14).

CONCLUSION

This meta-analysis confirmed the risks of night shift work for the development of overweight and obesity with a potential gradient association suggested, especially for abdominal obesity. Modification of working schedules is recommended, particularly for prolonged permanent night work. More accurate and detailed measurements on shift work patterns should be conducted in future research.