Harnessing genetic engineering to drive economic bioproduct production in algae

Our reliance on agriculture for sustenance, healthcare, and resources has been essential since the dawn of civilization. However, traditional agricultural practices are no longer adequate to meet the demands of a burgeoning population amidst climate-driven agricultural challenges. Microalgae emerge as a beacon of hope, offering a sustainable and renewable source of food, animal feed, and energy. Their rapid growth rates, adaptability to non-arable land and non-potable water, and diverse bioproduct range, encompassing biofuels and nutraceuticals, position them as a cornerstone of future resource management. Furthermore, microalgae's ability to capture carbon aligns with environmental conservation goals. While microalgae offers significant benefits, obstacles in cost-effective biomass production persist, which curtails broader application. This review examines microalgae compared to other host platforms, highlighting current innovative approaches aimed at overcoming existing barriers. These approaches include a range of techniques, from gene editing, synthetic promoters, and mutagenesis to selective breeding and metabolic engineering through transcription factors.

Treatment Modalities to Manage Hepatocellular Carcinoma Patients with Portal Vein Thrombus: A Systematic Review and Meta-Analysis

PURPOSE/OBJECTIVE(S)

Patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT) have poor outcomes and an effective treatment strategy has not been established. The aim of this review is to compare the effectiveness of available treatment options in preventing mortality.

MATERIALS/METHODS

A search was conducted in PubMed, EMBASE and Cochrane CENTRAL from 2007 to 2022. Articles were screened to identify studies of HCC patients with PVT that reported on all-cause mortality using radical intent treatments. Study quality was assessed using the Cochrane Risk of Bias in Non-Randomized Studies of Interventions tool (ROBINS-1). Mortality rates at prespecified timepoints between 6 and 24 months were extracted and summarized using a random-effects DerSimonian-Laird model. This review was registered a priori on PROSPERO (CRD42022290708).

RESULTS

The impact of radiotherapy (RT) on overall survival (OS) is similar to all other treatments including sorafenib. When comparing sorafenib to local modalities (Y90 and RT), the local treatments had a better OS (OR 2.20, 95% CI: 1.11 - 4.39), but this difference disappeared after 6-months. Indeed, within 6 months, Y90 provided the best OS. No significant differences were noticed from 12 to 24 months. Combination treatments appeared to provide a significant additional OS benefit with TACE+RT having an improved OS over TACE alone and RT alone, with the benefit extending to 24 months.

CONCLUSION

this analysis of HCC patients with PVT reports on six cohorts, with a total sample size of 2,356 patients. The addition of localized treatment to systemic treatment appears to improve survival. Combining TACE and RT was also better than either modality alone. Further investigations should be conducted, to further understand the role of localized treatments.

Trends in outcomes, complications and readmission rates in patients undergoing transcatheter aortic valve implantation: a nationwide analysis from 2012 to 2019

Background

Transcatheter aortic valve implantation (TAVI) has evolved over the years from a procedure requiring surgical vascular access and general anesthesia, to one that can be completed entirely percutaneously with conscious sedation. Advancement in procedural techniques and operator experience has resulted in better outcomes for patients undergoing TAVI.

Purpose

The purpose of our study was to analyze the trends over the years in outcomes, complications and unplanned readmission rate in patients undergoing TAVI.

Methods

The United States Nationwide Readmission Database for the years 2012 to 2019 was queried to identify all adult patients who underwent elective TAVI. The primary outcome of the study was inpatient mortality during TAVI hospitalization. Secondary outcomes included periprocedural complications (like acute kidney injury, bleeding requiring transfusion, need for permanent pacemaker implantation, stroke), length of stay, hospitalization cost, and unplanned 30-day readmission rate. Appropriate International Classification of Diseases (ICD-9 and ICD-10) codes were used to identify comorbidities and complications.

Results

A total of 283,409 patients who underwent TAVI were included in the study. The baseline characteristics of these patients are shown in picture 1. The inpatient mortality during TAVI admission declined steadily and significantly from 5.3% in the year 2012 to 0.0% in the year 2019 (p value for trend <0.001). There was a significant reduction in peri-TAVI occurrence of acute kidney injury (from 18.1% in 2012 to 8.7% in 2019), bleeding requiring transfusion (from 28.0% in 2012 to 4.3% in 2019), and stroke (from 1.8% in 2012 to 0.1% in 2019) (p value for trend <0.001 for all). Periprocedural conduction abnormalities requiring permanent pacemaker implantation increased from 7.4% in 2012 to 12.1% in 2015, before coming down to 8.9% in 2019 (p value for trend <0.001). The mean length of hospital stay and inflation-adjusted costs during admission for TAVI decreased from 9.6 days and $64,695 in the year 2012, to 3.6 days and $49,710 in the year 2019, respectively (p value for both <0.001). The unplanned 30-day all-cause readmission rate after TAVI also reduced steadily and significantly from 18.2% in 2012 to 11.5% in 2019 (p value <0.001).

Conclusion

Over the years, there has been a significant reduction in inpatient mortality, periprocedural complications (such as acute kidney injury, need for blood transfusion, stroke), length of hospital stay, and inflation-adjusted hospital costs in patients undergoing transcatheter aortic valve implantation. Furthermore, there has been a significant decline in the 30-day unplanned readmission rate after transcatheter aortic valve implantation.

Funding Acknowledgement

Type of funding sources: None.

Incidence of in-hospital all-cause mortality, resource utilization and complications in patients with adult congenital heart disease undergoing TAVR-a national inpatient sample study

Background

The prevalence of congenital heart disease (CHD) in adults in the United States is approximately 1.4 million. (1) With the advancement in diagnostic modalities and advanced treatments, including minimally invasive techniques, the life expectancy of individuals with CHD has greatly improved. (2) As these patients enter the 8th decade of their lives, the risk of calcification and aortic stenosis increases like the population without CHD. Current evidence supports transcatheter aortic valve replacement (TAVR) over surgical aortic valve replacement in individuals with moderate to high surgical risk. (3) Adults with acyanotic CHD (ACHD) with a higher risk for surgical complications are candidates for consideration of TAVR. There are sparse data about the cardiovascular outcome in these patients.

Purpose

With this National inpatient sample (NIS) study, the authors have shown the incidence of in-hospital all-cause mortality, resource utilization, and complications in adult patients with ACHD undergoing TAVR.

Methods

NIS 2016–2018 were utilized to conduct the study. Analyses were performed using STATA, version 16.0. Using appropriate ICD-10-PCS codes, authors identified adult patients with ACHD undergoing TAVR. The primary outcome of the study is to identify the impact of ACHD on all-cause in-hospital mortality and complications. Secondary outcomes of interest were resource utilization.

Results

134,170 patients were identified who had TAVR done between 2016–2018. Patients aged ≤18 years were excluded (N=25). Out of 134,170 patients that underwent TAVR, 1,170 (0.87%) were noted to have ACHD. Using the greedy algorithm, 1,115 matched pairs were generated. The ACHD group had a higher burden of co-morbidities including atrial fibrillation (46.2% vs. 38.8%, p=0.016), pulmonary hypertension (27.4% vs. 17.5%, p<0.001), metabolic syndrome (1.3% vs. 0.3%, p=0.005), peripheral vascular disease (29.5% vs. 24.1%, p=0.049), alcohol use disorder (3.0% vs. 1.3%, p=0.018), coagulation disorder (22.7% vs. 12.8%, p<0.001), drug abuse (1.3% vs. 0.4%, p=0.043), liver disease (7.3% vs. 3.1%, p<0.001) and electrolyte disturbances (20.5% vs. 14.9%, p=0.017). We also noted a possible trend towards higher complication odds (cardiac complications such as the need for pericardial drain or cardiac implantable electronic device and cardiac arrest) in patients with ACHD undergoing TAVR without statistical significance based on multivariate analysis. On propensity matching, no difference was found in the incidence of overall cardiac complications between patients with ACHD and patients without ACHD, except STEMI (OR 4.16, 95% CI, 1.08–16.00, p=0.038).

Conclusion(s)

The study points towards the possible safety of pursuing TAVR in ACHD patients provided adequate technical support and operator competency.

Funding Acknowledgement

Type of funding sources: None.

Same-day discharge following transcatheter aortic valve replacement: a propensity-matched analysis from national readmission database

Background

The length of hospital stay following transcatheter aortic valve replacement (TAVR) has decreased in recent years, and next-day discharge strategy is being increasingly adopted in some centers. Whether it is safe to further expedite discharge post-TAVR in selected patients by allowing discharge on the same day as the procedure remains unknown. In addition to potentially decreasing hospitalization costs, it could also limit the inpatient footprint and strain on healthcare resources.

Purpose

The purpose of our study was to compare the 30-day readmission rate in patients receiving TAVR who were discharged the same day (same-day discharge or SDD group) with those who were discharged on a different day (different-day discharge or DDD group). Additionally, we aimed to identify risk factors for readmission after TAVR.

Methods

We used the United States Nationwide Readmission Database to identify all adults who underwent elective TAVR in the years 2015–2019. The primary outcome of this study was all-cause 30-day readmission rate. The secondary outcomes were total hospital costs for the index admission, and risk factors for 30-day readmission. Propensity score matching was conducted to compare the SDD and DDD groups. Independent risk factors of 30-day readmission were identified using multivariate Cox proportional hazards regression analysis of the unmatched cohort.

Results

Of the 196,618 patients who received TAVR (mean age 79.5±8.4 years, 45.0% females), 245 (0.12%) patients were discharged on the same day they received TAVR (SDD group), and the remaining 196,373 were discharged on a different day (DDD group). In the DDD group, the median length of hospital stay was 2 days (interquartile range 1–4 days). A 1:3 propensity score analysis generated a matched cohort including 245 and 889 patients in the SDD and DDD groups, respectively. The 30-day readmission rate was similar between the SDD and DDD groups (11.0% versus 10.8%, hazard ratio [HR] 1.01, 95% confidence interval [CI] 0.59–1.71, p=0.989). Hospitalization costs were significantly lower in the SDD group than the DDD group ($37,811±18,029 versus $49,130±27,007, p<0.001) (see Picture 1). Age, female gender, history of diabetes, chronic kidney disease, chronic pulmonary disease, oxygen use, prior stroke, peripheral vascular disease, anemia, liver disease, and cancer were found to be independent risk factors for 30-day readmission after TAVR (see Picture 2).

Conclusion

In this large nationwide database analysis, patients receiving uncomplicated TAVR who were discharged on the same day as the procedure had a similar all-cause 30-day readmission rate and significantly lower hospital costs compared to those discharged on a different day. These results indicate that same-day discharge after TAVR may be a safe and feasible option in carefully selected patients.

Funding Acknowledgement

Type of funding sources: None.

Meta-analysis comparing the efficacy of dobutamine versus milrinone in acute decompensated heart failure and cardiogenic shock

Objective

This study aims to evaluate the difference between dobutamine and milrinone in patients presenting with acute decompensated heart failure (AHF).

Background

Inotropes are indicated for treating AHF, especially in patients with concomitant hypoperfusion indicative of cardiogenic shock. However, previous studies have not identified the optimal inotrope. We sought to compare outcomes associated with milrinone versus dobutamine in patients with AHF.

Methods

A systematic literature search was performed to identify relevant trials from inception to August 2021. Our primary outcome of interest was mortality. Analysis was sub-categorized according to subpopulation, including AHF, AHF with cardiogenic shock (AHF-shock), AHF with a bridge to transplantation (AHF-BTT), and AHF with destination therapy (AHF-DT). Summary effects were calculated using a fixed-effects model as risk ratio or mean difference with 95% confidence intervals for all the clinical endpoints.

Results

Ten studies, including one randomized controlled trial with 21,106 patients, were included in the analysis (4918 patients were in the Milrinone group, while 15188 were in the Dobutamine group). Milrinone was associated with a lower risk of mortality in patients with AHF [relative risk (RR) 0.87; confidence interval (CI):0.79–0.97; p<0.05, heterogeneity I2=0%] with event rates of 9.4% vs. 9.8% [number needed to treat (NNT) of 250]. Milrinone was also associated with improved mortality with RR 0.76 (0.79–0.95; p<0.05) in patients with AHF-DT. There was a non-significant trend towards improved mortality in AHF-shock patients. However, AHF-BTT patients had a non-significant trend towards improved mortality with dobutamine. There was no difference between the two strategies for the outcomes of acute kidney injury, initiation of renal replacement therapy, mechanical ventilation, arrhythmias, symptomatic hypotension, and length of hospital stay (LOS) in the overall population. Intensive care unit (ICU) LOS was lower in AHF-shock patients in the milrinone group, whereas dobutamine was associated with a lower length of ICU stay in AHF patients.

Conclusion

The cumulative data comparing milrinone with dobutamine indicate an overall marginal benefit of milrinone compared to dobutamine in the totality of patients with AFH with or without cardiogenic shock, and whether or not they are bridged to transplantation or destination assist device. More appropriately powered prospective studies are needed to identify a conclusive benefit of one inotrope over another.

Funding Acknowledgement

Type of funding sources: None.

Trends in the prevalence of infiltrative cardiomyopathy among patients with in-hospital cardiac arrest – insight from the US national inpatient sample database

Background

Sarcoidosis, amyloidosis, hemochromatosis and scleroderma are the most common systemic disorders leading to infiltrative cardiomyopathy (InCM). Each of them has been associated with conduction abnormalities and sudden cardiac death. In patients who undergo in-hospital cardiac arrest, a high index of suspicion is required to rule out InCM as an underlying contributor.

Purpose

We aimed to analyse the temporal trend in the prevalence of InCM among patients with in-hospital cardiac arrest and identify factors associated with increased mortality in this population.

Methods

We analysed data from the National Inpatient Sample (NIS), which is the largest publicly available database of in-hospital patients in the Unites States. Using ICD-10 coding, we identified patients who were hospitalized across 10 years from 2010–2019. Patients with diagnosis codes for both cardiac arrest and a subtype of InCM were included. Demographic characteristics and co-morbidity data were collected. Statistical analysis was performed using STATA.

Results

The total number of patients with a diagnosis of in-hospital cardiac arrest was 19,34,260. Of these, the total number with InCM was 14,803 (0.77%), which comprised our study population. Mean age was 63 years. The overall prevalence of InCM across the years ranged between 0.75 to 0.9%, with a significant temporal increase (p<0.01). Prevalence of females ranged between 51% to 62% and significantly outnumbered males across the time period. (p=0.011). Incidence of in-hospital mortality ranged between 61% to 76% for females and 30 to 38% for males. Race based analysis showed that prevalence of Caucasians ranged from 51% to 62% while that of African Americans (AA) ranged from 57% to 73%. The incidence of mortality was similar in both populations. Sarcoidosis was the most prevalent form of InCM, accounting for nearly two-fifths of all cases while amyloidosis and scleroderma both accounted for nearly 20% each. Haemochromatosis was present in 10% of the population. Overall mortality rate in our study population was 60.6%. The following co-morbidities were more prevalent in patients with InCM than those without: history of heart failure, chronic obstructive pulmonary disease (COPD), chronic kidney disease, anaemia, malignancy, coagulopathy, ventricular tachycardia, acute kidney injury and stroke. The following factors were independent predictors of in-hospital mortality-age (p=0.001), female gender (p=0.016), Hispanic race (p=0.039), history of COPD (p<0.001) and presence of malignancy (p=0.042).

Conclusion

The prevalence of infiltrative cardiomyopathy in patients with in-hospital cardiac arrest is increasing. Females, older patients and Hispanic population are at an increased risk of mortality. Sex and race based disparities in the prevalence of InCM in patients with in-hospital cardiac arrest is an area of further research.

Funding Acknowledgement

Type of funding sources: None.

Impact of age on the utility of CardioMEMs device to guide heart failure therapy: analysis of the National Readmissions Database

Background

Weeks before patients exhibit signs and symptoms of HF, intracardiac and pulmonary artery pressures increase, offering a potential target for early intervention. The CardioMEMs device is an implantable hemodynamic device placed directly into a branch of the pulmonary artery (PA) which allows remote PA pressure monitoring. The aim of our analysis is to compare outcomes of patients admitted with HF receiving implanted CardioMEMs based on their age.

Methods

Data from the National Inpatient Sample (NIS) database from 2014–2019 was used to identify hospitalizations with International Classification of diseases – 9th Revision and International classification of Diseases – 10th Revision procedural codes of patients with heart failure and CardioMEMs implantation. The outcome of interest was readmission rates at 30 days and complications associated with device implantation.

Results

We identified 1841 hospitalizations: 708 (38.5%) for patients <65 years-old (mean age 53.6) and 1,113 (60.1%) for patients >65 years-old (mean age 79.5). Gender was similar between the two age cohorts with females representing 36.6% vs 37.7% of the patients (<65 and >65 years old respectively). The cohort of patients >65 years of age had a higher rate of comorbidities including hypertension (87.9% vs 80.2%; p=0.003), prior CABG (20.3% vs 8.5%; p = <0.001), atrial fibrillation (59.2% vs 38.4%; p = <0.001), PPM (10.9%% vs 2.3%; p = <0.001), and ESRD (56.1% vs 47.3%; p=0.015. The presence of LVAD prior to device implantation was higher in the <65-year-old group at 2.8% vs 1.2% (p=0.065). Diabetes, prior PCI, PVD, pulmonary disease, anemia, cancer, and oxygen dependence were similar among the two cohorts and not statistically significant. Complications including acute kidney injury requiring dialysis, stroke, and transplant post CardioMEMs implantation were similar among the two groups. The patients who survived the index hospitalization, readmission rates were significantly improved in the cardioMEMs arm patients who were <65 years of age (13.8% vs 21.9%) compared to those 65 and above (19.6% vs 20.5%), p for interaction <0.001, Figure 1.

Conclusion

The CardioMEMS device is more effective in a younger patient population to reduce HF admissions.

Funding Acknowledgement

Type of funding sources: None.

Pulmonary artery pressure-guided therapy in patients with heart failure using the CardioMEMS device and HF readmissions: analysis of the National Readmissions Database

Background

Pulmonary artery pressure (PAP)-guided therapy in patients with heart failure (HF) using the CardioMEMS device (CMM), an implantable PAP sensor, has shown to reduce HF hospitalizations in previous studies. We sought to evaluate the clinical benefit of the CMM device in regard to 30-day, 90-day and 180-day readmission rates in real-world usage.

Methods

We queried the National Readmission Database (NRD) to identify patients who underwent CMM implantation (ICD 9 & 10 codes) between the years 2014 to 2019 and studied their HF readmissions. We compared CMM patients and their readmissions with a matched cohort of patients with HF without CMM. Multivariable Cox regression analysis was performed to adjust for other predictors of readmissions.

Results

Prior to matching we identified 5,326,530 weighted HF patients without CMM and 1842 patients with CMM. After propensity score matching for several patients and hospital related characteristics, the cohort consisted of 1839 patients with CMM and 1924 with HF without CMM. Before matching, CMM patients were younger (67.0±13.5 years vs 72.3±14.1 years, P<0.001), more frequently males (62.7% vs 51.5%, P<0.001), with higher rates of prior percutaneous coronary intervention (16.9% vs 13.2%, P=0.002), peripheral vascular disease (29.6% vs 17.8%, P<0.001), pulmonary circulatory disorder (38.7% vs 23.2%, P<0.001), atrial fibrillation (51.2% vs 45.3%, P=0.002), prior left ventricular assist device (1.8% vs 0.2%, P<0.001), high income (32.2% vs 16.4%, P<0.001) and acute kidney disease (43.8% vs 29.9%, P<0.001). Readmission rates at 30-days were 17.3% vs. 20.9% for patients with vs. without CMM respectively and remained statistically significant after matching (17.3% vs. 21.5%, p=0.002). The rates of 90-day (29.1% vs 36.5%, p=0.002) and 180-day (39.6% vs. 46.6%, p=0.009) readmissions were lower in the CMM group. In a multivariable regression model, CMM was associated with lower risk of readmissions (HR, 0.75, 95% CI 0.63–0.89, p=0.001).

Conclusion

The CMM device was associated with reduced HF rehospitalization rates in a nationally representative cohort of HF patients.

Funding Acknowledgement

Type of funding sources: None.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

Primary retrograde urinary drainage using image and endoscopy guidance via urostomies

AIM

To report the technical success of image and endoscopy-guided retrograde trans-urostomy urinary drainage as a primary catheter placement method performed by interventional radiology (IR).

MATERIALS AND METHODS

Nine patients (15 attempted drain placements) with ureteric obstruction following radical cystectomy and urostomy creation were included. The patients were referred to IR for urinary drainage. All patients underwent primary image and endoscopy-guided retrograde trans-urostomy urinary drainage.

RESULTS

Primary image and endoscopy-guided retrograde trans-urostomy urinary drainage was successful in 13/15 (86.6%) attempts. The proposed technique had a limited complication rate omitting the percutaneous nephrostomy access step.

CONCLUSION

Primary image and endoscopy guided retrograde trans-urostomy urinary drainage should be considered before percutaneous nephrostomy in all patients with a urostomy.

56 A Quality Improvement Project to Assess and Refine the Handover Process at Morning Trauma Meetings

Aim

Poor handover and inadequate transmission of clinical information between shifts can result in patient harm. This study was designed to evaluate the impact of implementing a handover protocol on the quality of information exchanged in the trauma handover meetings in a UK district general hospital.

Method

A prospective single centre observational study was performed at an acute NHS trust, using the define, measure, analyse, improve and control (DMAIC) methodology. Ten consecutive weekday trauma meetings, involving 43 patients, were observed to identify poor practices in handover. This data was used in conjunction with the Royal College of Surgeon’s recommendations for effective handover (2007) to create a standard operating protocol (SOP). Following the implementation of the SOP, a further eight consecutive weekday trauma meetings, involving a further 47 patients, were observed. The data collection was performed by five trained independent observers. The data was analysed using t-test for quantitative variables and chi-square or Fisher’s exact tests for categorical variables.

Results

An improvement in the trauma handover was demonstrated in multiple aspects of handover including patient’s past medical history, injury date, results, diagnosis, consent, mark and starvation status (all p &lt; 0.001). Subgroup analyses showed that handover of neck of femur patients including information on mobility (p = 0.04), Nottingham Hip Fracture Score (p = 0.01), next of kin discussion (p = 0.075) and resuscitation status (p = 0.001) all improved following our interventions.

Conclusions

These results demonstrate that the implementation of a well-structured handover protocol can improve the transmission of critical information in trauma meetings.

Conflicting attitudes: Analyzing social media data to understand the early discourse on COVID-19 passports

In several countries, vaccine passports are being encouraged to hasten the return to some form of normalcy amidst the COVID-19 pandemic. Vaccine passport is a digital or paper document that may serve as proof of the COVID-19 vaccine, thereby allowing entry to public venues, sporting events, air travel, and unrestricted access to other facilities. This study explores how the COVID-19 passport is being discussed and perceived on Twitter and the prominent entities involved in the early discourse on the issue. Twitter messages were theoretically analyzed for Health Belief Model (HBM) and Theory of Planned Behavior (TPB) variables, as well as message source, engagement, and attitudes towards vaccination certificates. Using quantitative content analysis, tweets were coded on nine dimensions: account type, tweeter profile, tweet content, tweet modality, attitude, self-efficacy, perceived barriers, benefits, and action cues. Most of the tweets originated from personal accounts, followed by media organizations, media-related personalities, politicians, and the travel industry. A significant number of tweets were from male Twitter users. Our analysis revealed that most tweeters had a favorable attitude towards the COVID-19 passports. Unfavorable attitudes toward the COVID-19 passport were based on reasons such as a lack of common standard or consensus, and personal freedoms & human rights. Tweets highlighting the benefits of COVID-19 passports cited travel as the primary reason. Based on a combination of technical, legal, and ethical practices, our study offers a set of vital recommendations for governments, health organizations, and businesses that may help stimulate the acceptance of vaccine passports.

Transcatheter aortic valve implantation outcomes compared between bicuspid aortic and tricuspid aortic valve stenosis: an updated systematic review and meta-analysis

Background

TAVI has emerged as an attractive treatment modality based on promising recent trial data. Patients with BAV, a commonly encountered clinical condition have largely been excluded from a majority of trials.

Purpose

Elderly patients with BAV and severe AS are increasingly encountered in clinical practice. This meta-analysis compares clinical outcomes between bicuspid and tricuspid AV patients to address the current knowledge-gap and identify optimal management strategies of these patients.

Methods

A comprehensive literature search was performed in PubMed, Embase, and Cochrane to identify the available observational studies comparing outcomes of TAVI in BAV and TAV patients. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints.

Results

16 Observational studies met inclusion criteria, comprising 10,053 patients with BAV and 173,307 patients with TAV that underwent TAVI. No significant differences in 30-day and long-term mortality rates were observed. Patients with BAV had an increased risk of stroke (OR 1.23; 95% CI [1.06–1.44], p=0.007), re-intervention (OR 1.90; 95% CI [1.15–3.15], p=0.01), paravalvular leak (OR 1.42; 95% CI [1.25–1.61], p&lt;0.ehab724.22251), conversion to open surgery (OR 1.93; 95% CI [1.21–3.07], p=0.006), and new pacemaker implantation (1.57; 95% CI (1.06 - 2.33, p=0.02). Adverse event rates are lower with the use of newer generation of valves. No significant difference in major vascular complications, major bleeding, or incidence of AKI was noted.

Conclusions

Complication rates for BAV TAVI are higher, but mortality is similar to TAV TAVI indicating TAVI is an appropriate alternative for intermediate-high risk patients with BAV. A better understanding of valve anatomy, physician expertise, the use of newer-generation valves can help reduce these complications.

Funding Acknowledgement

Type of funding sources: None.

Trends, risk factors and mortality of unplanned 30-day readmission after heart transplantation

Introduction

Outcomes after heart transplantation have improved, but the burden of readmissions is understudied. We sought to examine the incidence, risk factors, and associated mortality of unplanned 30-day readmissions following heart transplantation.

Methods

This cohort study examined patient data from the United States population-based Nationwide Readmissions Database. All adults (age ≥18 years) who underwent isolated heart transplantation in US hospitals between January to November of 2012 to 2018 were included. The primary outcomes were 30-day readmission rates and readmission mortality.

Results

A total of 14,784 patients who underwent heart transplantation from 2012 to 2018 were included in our analysis. A total of 3299 (22.3%) patients were readmitted within 30 days after discharge. The median time from discharge to readmission was 9 days, and approximately 70% of the readmissions occurred within 15 days. After multivariable analysis, only CKD (Hazard ratio (HR): 1.11 95% CI 1.00–1.23) and length of stay (HR: 1.002; 95% CI 1.001–1.003; p&lt;0.001) were associated with increased 30-day post-heart transplantation readmission. Readmissions diagnoses were heart transplantation complications, heart transplant rejection, postoperative infection, acute kidney injury, heart failure, pulmonary embolism, pneumonia, and pericardial effusion. The overall incidence of infection as a cause of readmission was 24.9%, with an associated mortality of 2.6% and a Median LOS of 7 days (4–14). The overall incidence of rejection was 38.0%, with a mortality of 1.2% and a median LOS of 5 days (3–8).

Conclusion

Approximately 1 in 5 patients will be readmitted within 30 days after heart transplantation, and most of those readmissions will occur during the first two weeks after discharge. Readmissions were associated with a low mortality rate.

Funding Acknowledgement

Type of funding sources: None.

Outcomes of permanent pacemaker insertion after TAVR: a systematic review and meta-analysis

Background/Introduction

Conduction abnormalities are frequently encountered after transcatheter aortic valve replacement (TAVR) performed for severe aortic stenosis, leading to post-procedure permanent pacemaker (PPM) insertion. Although the predictors of- and factors leading to post-TAVR PPM have been studied extensively, its short-term and long-term outcomes have not been established.

Purpose

PPM placement can lead to significant changes in outcomes in post-TAVR patients, which remain unclear. With this analysis, we aim to evaluate the differences between outcomes of patients requiring PPM and those not requiring PPM post-TAVR.

Methods

A comprehensive literature search was performed in PubMed, EMBASE, and Cochrane to identify relevant trials. Outcomes were compared between the two groups of patients- those requiring post-TAVR PPM and those not requiring post-TAVR PPM. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio (OD) with 95% confidence intervals (CI) for all the clinical endpoints.

Results

34 studies, including observational and prospective studies, met our inclusion criteria, with a total of 76,402 patients undergoing TAVR and 10,381 requiring post-TAVR PPM. There were no significant differences between 30-days (OR 1.04; 95% CI 0.96–1.13) and 1-year (OR 1.09; 95% CI 0.72–1.03) all-cause mortality rates, and 30-days (OR 0.86; 95% CI 0.72–1.03) and 1-year (OR 0.85; 95% CI 0.70–1.04) cardiovascular deaths among the two groups. Incidence of heart failure was higher in the post-TAVR PPM group at 30 days (OR 1.26; 95% CI 1.05–1.51) but not at 1 year (OR 1.21; 95% CI 0.93–1.57). No significant difference was noted between the two groups in 30-days or 1-year stroke, 30-days or 1-year myocardial infarction, 30-days or 1-year atrial fibrillation, 30-days or 1-year major bleeding, or 30-days and 1-year readmission rate. Other outcomes, including post-procedure aortic regurgitation, major vascular complications, minor bleeding, valve migration, and device success, also did not have any statistically significant difference in the two patient groups (Figure 1). Of all the patients who received post-TAVR PPM, an average of 46.4% and 58.5% patients had &gt;40% ventricular pacing, and 48.9% and 41.4% had &lt;40% ventricular pacing at 1-month, and 1-year follow up respectively.

Conclusions

Although there were no differences in the outcomes between the two groups at 30-days and 1-year follow-ups (except the higher incidence of heart failure at 30 days in the post-TAVR PPM group), long-term follow-up studies would be needed to identify any possible adverse events after one year. Also, a significant number of patients requiring post-TAVR PPM had &lt;40% ventricular pacing at 1-month and even at 1-year intervals, which might suggest adopting an alternate approach of closely monitoring any conduction disturbances and avoiding early PPM implantation in post-TAVR patients, if possible.

Funding Acknowledgement

Type of funding sources: None. Forest plot of differences in outcomes

Comparing loading strategies of P2Y12 inhibitors in patients undergoing elective PCI: a network meta-analysis

Introduction

Effective platelet inhibition prior to elective percutaneous coronary intervention (PCI) reduces the risk of ischemic complications. Newer P2Y12 inhibitors are preferred agents over clopidogrel for patients presenting with acute coronary syndrome. However, the comparative efficacy and safety of them over clopidogrel in elective PCI is unclear. Our objective was to perform a network meta-analysis and assess that from randomized controlled trials (RCT).

Methods

We conducted a systematic review of RCTs up to and including November 2020. The endpoints of interest were overall mortality, rates of myocardial infarction (MI), stroke, revascularization and major bleeding. Random effects model using frequentist approach was used to perform a network meta-analysis using R software.

Results

5 trials with total of 5,194 patients were included in our analysis. For ischemic outcomes including MI, Stroke and revascularization, prasugrel had the most favorable trend. However, clopidogrel had the highest probability of being most effective for major bleeding and all-cause mortality. None of these trends were statistically significant due to lack of power for each individual outcome (Figure 1).

Conclusion

Prasugrel and ticagrelor seem to show better efficacy in preventing MI and stroke. However, their effects are marginal and do not translate into improved overall mortality and bleeding. Therefore, in this lower risk population presenting for elective PCI, clopidogrel remains a reasonable P2Y12 inhibitor choice in lower risk population.

Funding Acknowledgement

Type of funding sources: None. Results

774 Paediatric Appendicitis Score (PAS): A Local Trial of a Risk Prediction Pathway

Aim

Right iliac fossa (RIF) pain remains the commonest acute general surgical presentation in children. Our centre had been an outlier compared with the national average in terms of negative appendicectomy rates. Thus, we designed and implemented a local pathway for risk stratification and management of children with RIF pain.

Method

The first phase was a retrospective analysis of all appendicectomies performed between April 2018 and March 2019, in children aged five to seventeen years old. Pre-operative inflammatory markers, clinical signs, and histology findings were analysed. Second phase involved designing a pathway utilizing Paediatric Appendicitis Score (PAS), a ten-point scoring system when assessing children with RIF pain. The final phase was a prospective analysis of appendicectomy results performed between August and November 2019, after implementing PAS pathway.

Results

92 cases were recruited in the first phase (mean age 12.3). 22 cases were analysed in the final phase after implementing PAS pathway (mean age 10.9). Our negative appendicectomy rates had reduced from 25% to 15.4%. In addition, we found that 96% of positive appendicectomies had either raised inflammatory markers (WCC or CRP), raised PAS (Score of ≥ 4), or both.

Conclusions

There is noticeable difference in our negative appendicectomy rates since the introduction of PAS pathway. A diagnosis of appendicitis in a child with normal inflammatory markers and PAS score seemed unlikely. Our goal is to continue utilizing the PAS pathway in our department in order to reduce unnecessary surgeries in children.

Body composition, growth performance and enzyme activities of Labeo rohita fed different commercial fish feeds

We have evaluated the effects of different fish feeds on the body composition, growth, and enzyme activities of Labeo rohita (Rohu). In total, 240 fishes between the average weights of 24.77±2.15g were studied. The treatments were applied in a completely randomized design, with 4 treatments of 60 fishes each. Treatments consisted of four different fish feeds [Oryza (T1), AMG (T2), Aqua (T3), and Supreme (T4)]. Body composition, growth performance, and enzyme activities were evaluated. There was a significant variation in performance of fishes fed with different type of feed; as fishes having Oryza feed showed the highest weight gain, specific growth rate (SGR), and best feed conversion ratio (FCR) as compared to other groups that were considered to be significant (P ≤ 0.05). High net weight gain was obtained in T4 when compared with T2 and T3. FCR value of T4 was less than T1 but higher than T2, T3 and T2, which showed the lowest values. The specific growth rate was recorded as average in T4, but T2 led a high SGR than T3. Similarly, crude protein level and digestive enzymes activity was recorded significantly highest in fed with Oryza (T1) as compared to AMG (T2), Aqua (T3), and Supreme (T4). Water quality parameters were recorded significant in all treatments except pH and DO of treatment (T1), significantly different from other treatments. It was concluded that Rohu (Labeo rohita) could show a promising growth rate and protease enzyme activity when fed with the Oryza feed of 25% protein.

Impact of dietary leaf extracts of Black pepper Piper nigrum L. on the growth, hematological and immunological parameters of Labeo rohita (Hamilton, 1822) cultured in glass aquaria

A study was conducted to evaluate the effect of Piper nigrum (black pepper) leaf extract on on the growth performance, proximate composition, hematological parameters, and immune response of Labeo rohita fingerlings with an average weight of 22.14 ± 0.98g. Aftrer acclimation for two weeks, fish (n=25) were randomly selected and placed in four glass aquaria (T0, T1, T2 and T3) at constant water temperature (30.0 ± 1.0 °C), pH (7.50 ± 0.5) and total hardness (200 ± 2.0 mgL,-1) for a period of 12 weeks, with three replicates each. Fish were fed with P. nigrum leaf extract supplemented feed @ 0.0%, 1.0%, 2.0% and 3.0% in T0, T1,T2 and T3, respectively. At the end of experiment, five fish were randomly selected from each aquaria for proximate composition, gut and skin microbial load, hematological parameters. Total proteins, albumins, and globulins were also recorded to evaluate immunological memory. The result revealed that fish in T2 showed better growth performance with an average weight gain of 56.11 ± 0.51 g. Thus, it had been concluded that Piper nigrum, a medicinal plant, can also be used to enhance the growth performance and immune response of Labeo rohita as attractive alternatives against antibiotics and vaccines and has shown no negative side effects on fish health as well as on its environment.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

49 A Quality Improvement Project to Assess and Refine the Handover Process at Morning Trauma Meetings

Introduction

Poor handover between shifts can result in patient harm. This study was designed to evaluate the impact of implementing a handover protocol on the quality of information exchanged in the trauma handover meetings in a UK hospital.

Method

A prospective single-centre observational study was performed at an NHS Trust. Ten consecutive weekday trauma meetings, involving 43 patients, were observed to identify poor practices in handover. This data was used in conjunction with the Royal College of Surgeons’ recommendations for effective handover (2007) to create and implement a standard operating protocol (SOP). Following its implementation, a further 8 consecutive meetings, involving a further 47 patients, were observed. The data was analysed using t-test for quantitative variables and chi-square or Fisher’s exact tests for categorical variables.

Results

An improvement was demonstrated in multiple aspects of trauma handover including past medical history, injury date, results, diagnosis, consent, mark, and starvation status (all p &lt; 0.001). Subgroup analyses showed that handover of neck-of-femur fracture patients including information on baseline mobility (p = 0.04), Nottingham-Hip-Fracture Score (p = 0.01), next-of-kin discussion (p = 0.075) and resuscitation status (p = 0.001) all improved following the intervention.

Conclusions

These results demonstrate that the implementation of a well-structured handover protocol can improve the transmission of critical information in trauma meetings.

Coronary angioplasty and COVID-19: are heparin requirements and thrombotic complications increasing?

Funding Acknowledgements

Type of funding sources: None.

Background

Covid-19 infection is associated with coagulopathy and possible heparin resistance, raising concerns that routine heparin during percutaneous coronary intervention (PCI) is failing to achieve adequate anticoagulation. We examined heparin requirements and efficacy in patients treated by PCI before and after the first reported UK case of Covid-19 (January 31st 2020).

Methods

We retrospectively compared heparin dose, Activated Clotting Time (ACT) and coronary flow (TIMI grade) for PCI procedures at a London cardiac centre in the 3 months before the UK pandemic and the three months afterwards. Testing for COVID was not routinely performed. Pre-specified analyses in patients with STEMI, NSTEMI and Stable angina were undertaken.

Results

Of 1227 PCI procedures performed over the period of observation, 690 were pre-pandemic and 537 were afterwards. Overall median heparin dose per case was 11000units versus 11500units (p = 0.137) and maximum ACTs were 291s versus 305s, respectively (p = 0.135). Pre-PCI TIMI 3 flow was lower during the pandemic than before (60% v 65%, p = 0.005) but Post-PCI flow was similar (96% versus 96%, p = 0.839). There were no statistically significant differences in heparin dose or achieved ACT among patients with STEMI, NSTEMI or Stable presentations.

Conclusion

In spite of the increasing evidence that COVID-19 infection causes thrombosis, it appears that standard heparin management during PCI is sufficient to achieve effective anticoagulation and avoid peri-procedural thrombotic complications.

	Group 1 Pre Pandemic	Group 2 Pandemic	P value
Number of doses given	3 (3 to 4)	3 (3 to 4)	0.952
Total Heparin dose (units)	11000 (8000 to 14000)	11500 (9000 to 14000)	0.137
Number of ACTs measured	2 (1 to 2)	2 (1 to 2)	0.194
First ACT (seconds)	240 (199 to 318)	248 (206 to 326)	0.256
Maximum ACT (seconds)	291 (230 to 368)	305 (239 to 369)	0.135

Heparin dose and Activated Clotting Times (ACT) in patients undergoing PCI before Covid-19 pandemic (Group 1) and during pandemic (Group 2); median and interquartile ranges

CYP1A2, 2A13, and 3A4 network and interaction with aflatoxin B1

Aspergillus fungi are known to produce aflatoxins, among which aflatoxin B1 (AFB1) is the most potent carcinogen that is metabolised by cytochrome P450 (CYP450). In the liver, AFB1 is metabolised into exo-8,9-epoxide by the CYP1A2 enzymes. The resulting epoxide can react with guanine to cause DNA damage. Natural inhibitors are being identified. However, the modes of action are poorly understood. In the current study, we have investigated the mode of action of AFB1 with CYP1A2, CYP3A4 and CYP2A13 using molecular dynamic simulation (MD simulation) approaches. The interaction network and paths among CYP1A2, CYP3A4, and CYP2A13 have been investigated using the STRING database and PathLinker plugin of Cytoscape. CYP3A4 is the most active protein involved in interactions with AFB1 during its metabolism. Residues 362ARG, 445SER, 450LEU and 451PHE of CYP1A2 are important, interacting with AFB1 and converting it to toxic exo-AFB1-8,9-epoxide (AFBEX). The pathway shows that microsomal epoxide hydrolase (EPHX1) may acts as initiator in the signalling pathway where CYP1A2, CYP3A4 and CYP2A13 interact in a sequential order. The interaction network shows there to be a strong association in expression among CYP1A2, CYP3A4 and CYP2A13 along with other metabolising enzymes. The complex of AFB1 and CYP1A2 was found to be stable during the MD simulation. This study provides a better understanding of the mode of action between AFB1 and CYP1A2, CYP3A4 and CYP2A13 which relates to the effective management of AFB1 toxicity. EPHX1 in the protein network may be an ideal target when designing inhibitors to prevent the toxin’s activation. Peptide inhibitors may be designed to block the substrate site residues of CYP1A2 in order to prevent the conversion from AFB1 into AFBEX. This would either neutralise or reduce its toxicity.

In vitro Assessment of Tris Egg Yolk and Soybean Lecithin Based Extenders for Cryopreservation of Crossbred Ram Semen

BACKGROUND

The replacement of egg yolk with alternative plant-derived soybean lecithin is gaining interest in both animal and human sperm cryopreservation owing to biosecurity issues with egg yolk based extenders.

OBJECTIVE

To evaluate the comparative effect of egg yolk and soyabean lecithin based extenders on the quality of cryopreserved crossbred ram semen.

METHODS

Pooled ejaculates (total ejaculates = 36) were divided into two aliquots and extended with Tris egg yolk extender (Tris extender) and soybean lecithin based commercial extender (Ovixcell) RESULTS: Among the two extenders, Ovixcell showed better sperm quality both at the pre-freeze (Sperm motility) and post-thaw stages. Lower malondialdehyde (MDA) level (nmol/mL) was observed in Ovixcell as compared to Tris extender. Both sperm quality and MDA level decreased significantly (P < 0.05) from pre-freeze to post-thaw in both the extenders.

CONCLUSION

The findings of the present study indicate that Ovixcell is a comparable alternative to Tris extender for the cryopreservation of crossbred ram semen.

Relationship between country income, socioeconomic factors and control of cardiovascular disease risk factors in patients with type 2 Diabetes: insights from the global DISCOVER registry

Background

In patients with type 2 diabetes (T2D), optimal management of cardiovascular (CV) risk factors is critical for primary prevention of CV disease.

Purpose

To describe the association of country income and patient socioeconomic factors with risk factor control in patients with T2D.

Methods

DISCOVER is a 37-country, prospective, observational study of 15,983 patients with T2D enrolled between January 2016 and December 2018 at initiation of 2nd-line glucose-lowering therapy and followed for 3 years. In patients without known CV disease with sub-optimally controlled risk factors at baseline, we examined achievement of risk factor control (HbA1c &lt;7%, BP &lt;140/90 mmHg, appropriate statin) at the 3 year follow-up. Countries were stratified by gross national income (GNI)/capita, per World Bank report. We explored variability across countries in risk factor control achievement using hierarchical logistic regression models and examined the association of country- and patient-level economic factors with risk factor control.

Results

Among 9,613 patients with T2D but without CV disease (mean age 57.2 years, 47.9% women), 83.1%, 37.5%, and 66.3% did not have optimal control of glucose, BP, and statins, respectively, at baseline. Of these, 40.8%, 55.5%, and 28.6% achieved optimal control at 3 years of follow-up. There was substantial variability in achievement of risk factor control across countries (Figure) but no association of country GNI/capita on achievement of risk factor control (Table). Insurance status, which differed substantially by GNI group, was strongly associated with glycemic control, with no insurance and public insurance associated with lower odds of patients achieving HbA1c &lt;7%.

Conclusions

In a global cohort of patients with T2D, a substantial proportion do not achieve risk factor control even after 3 years of follow-up. The variability across countries in risk factor control is not explained by the GNI/capita of the country.

Proportion of patients at goal

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): The DISCOVER study is funded by AstraZeneca

Design of a closed-loop gastric pacemaker for modulating dysrhythmic conduction patterns via extracellular potentials

A potential treatment option for chronic and severe motility disorders such as gastroparesis is the implantation of a Gastric Electrical Stimulator (GES), which is designed to modulate the bio-electric slow waves. However, the effectiveness of current GESs remains uncertain since they do not work in a closed-loop by sensing, processing, and modulating the dysrhythmic patterns. This work presents the design of a GES model working in closed-loop with the network of the Interstitial Cells of Cajal (ICC). A pre-existing two-dimensional ICC network is enhanced by proposing an extracellular potential generation model, which can precisely capture the timing behaviour of slow wave propagation pattern of the simulated ICC network. The GES senses the extracellular potential, detects bradygastric patterns and finally modulates the activity to ensure normal conduction. The GES is designed to be practical for ease of validation and implementation.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.