Effects of Carotid Artery Stiffness on Cerebral Small-Vessel Disease and Cognition

Background Carotid artery stiffness is associated with cognitive impairment and dementia, but the underlying mechanisms remain unknown. We examined the associations of carotid artery stiffness with cerebral small-vessel disease markers, cognition, and dementia subtypes in a memory clinic cohort. Methods and Results A total of 272 participants underwent carotid ultrasonography, 3 Tesla brain magnetic resonance imaging, and neuropsychological assessment. Carotid ultrasonography was used to assess β-index, pressure-strain elastic modulus, and pulse-wave velocity-β. Brain magnetic resonance images were graded for cerebral small-vessel disease markers, including white matter hyperintensities, lacunes, and cerebral microbleeds. Participants were classified as having no cognitive impairment, cognitive impairment and no dementia, or dementia subtyped as Alzheimer disease and vascular dementia. Cognition was assessed using National Institute of Neurological Disorders and Stroke-Canadian Stroke Network harmonization battery. After adjusting for age, sex, cardiovascular risk factors, and diseases, multivariable models showed that β-index (β=0.69; P=0.002), elastic modulus (β=0.78; P<0.001), and pulse-wave velocity-β (β=0.80; P<0.001) were associated with white matter hyperintensities, and elastic modulus (odds ratio [OR], 1.39 [95% CI, 1.04-1.85]) and pulse-wave velocity-β (OR, 1.47 [95% CI, 1.10-1.98]) were independently associated with lacunes. Similarly, β-index (OR, 2.04 [95% CI, 1.14-4.13]), elastic modulus (OR, 2.22 [95% CI, 1.25-4.42]), and pulse-wave velocity-β (OR, 2.50 [95% CI, 1.36-5.18]) were independently associated with vascular dementia. Carotid stiffness measures were independently associated with worse performance in global cognition, visuomotor speed, visuospatial function, and executive function. These associations became largely nonsignificant after further adjusting for cerebral small-vessel disease markers. Conclusions In memory clinic patients, carotid artery stiffness was associated with white matter hyperintensities and lacunes, impairment in global and domain-specific cognition, and causative subtypes of dementia, particularly vascular. The effects of carotid stiffness on cognition were not independent of, and were partially mediated by, cerebral small-vessel disease.

Impact of COVID-19 on barriers to dispatcher-assisted cardiopulmonary resuscitation in adult out-of-hospital cardiac arrests in Singapore

OBJECTIVE

Fewer out-of-hospital cardiac arrest (OHCA) patients received bystander cardiopulmonary resuscitation during the COVID-19 pandemic in Singapore. We investigated the impact of COVID-19 on barriers to dispatcher-assisted cardiopulmonary resuscitation (DA-CPR).

METHODS

We reviewed audio recordings of all calls to our national ambulance service call centre during the pandemic (January-June 2020) and pre-pandemic (January-June 2019) periods. Our primary outcome was the presence of barriers to DA-CPR. Multivariable logistic regression was used to assess the effect of COVID-19 on the likelihood of barriers to and performance of DA-CPR, adjusting for patient and event characteristics.

RESULTS

There were 1241 and 1118 OHCA who were eligible for DA-CPR during the pandemic (median age 74 years, 61.6 % males) and pre-pandemic (median age 73 years, 61.1 % males) periods, respectively. Compared to pre-pandemic, there were more residential and witnessed OHCA during the pandemic (87 % vs 84.9 % and 54 % vs 38.1 %, respectively); rates of DA-CPR were unchanged (57.3 % vs 61.1 %). COVID-19 increased the likelihood of barriers to DA-CPR (aOR 1.47, 95 % CI: 1.25-1.74) but not performance of DA-CPR (aOR 0.86, 95 % CI: 0.73 - 1.02). Barriers such as 'patient status changed' and 'caller not with patient' increased during COVID-19 pandemic. 'Afraid to do CPR' markedly decreased during the pandemic; fear of COVID-19 transmission made up 0.5 % of the barriers.

CONCLUSION

Barriers to DA-CPR were encountered more frequently during the COVID-19 pandemic but did not affect callers' willingness to perform DA-CPR. Distancing measures led to more residential arrests with increases in certain barriers, highlighting opportunities for public education and intervention.

Prior Cancer Is Associated with Lower Atherosclerotic Cardiovascular Disease Risk at First Acute Myocardial Infarction

Background: Patients with cancer are at increased risk of acute myocardial infarction (AMI). It is unclear if the Atherosclerotic Cardiovascular Disease (ASCVD) risk score at incident AMI is reflective of this higher risk in patients with prior cancer than those without. Methods: We linked nationwide AMI and cancer registries from 2008 to 2019. A total of 18,200 eligible patients with ASCVD risk score calculated at incident AMI were identified (1086 prior cancer; 17,114 no cancer). Results: At incident AMI, age-standardized mean ASCVD risk was lower in the prior cancer group (18.6%) than no cancer group (20.9%) (p < 0.001). Prior to incident AMI, smoking, hypertension, hyperlipidemia and diabetes mellitus were better controlled in the prior cancer group. However post-AMI, prior cancer was associated with lower guideline-directed medical therapy usage and higher all-cause mortality (adjusted hazard ratio 1.85, 95% confidence interval 1.66−2.07). Conclusions: AMI occurred despite better control of cardiovascular risk factors and lower age-standardized estimated mean 10-year ASCVD risk among patients with prior cancer than no cancer. Prior cancer was associated with lower guideline-directed medical therapy post-AMI and higher mortality.

Microaxial Left Ventricular Assist Device in Cardiogenic Shock: A Systematic Review and Meta-Analysis

Microaxial left ventricular assist devices (LVAD) are increasingly used to support patients with cardiogenic shock; however, outcome results are limited to single-center studies, registry data and select reviews. We conducted a systematic review and meta-analysis, searching three databases for relevant studies reporting on microaxial LVAD use in adults with cardiogenic shock. We conducted a random-effects meta-analysis (DerSimonian and Laird) based on short-term mortality (primary outcome), long-term mortality and device complications (secondary outcomes). We assessed the risk of bias and certainty of evidence using the Joanna Briggs Institute and the GRADE approaches, respectively. A total of 63 observational studies (3896 patients), 6 propensity-score matched (PSM) studies and 2 randomized controlled trials (RCTs) were included (384 patients). The pooled short-term mortality from observational studies was 46.5% (95%-CI: 42.7–50.3%); this was 48.9% (95%-CI: 43.8–54.1%) amongst PSM studies and RCTs. The pooled mortality at 90 days, 6 months and 1 year was 41.8%, 51.1% and 54.3%, respectively. Hemolysis and access-site bleeding were the most common complications, each with a pooled incidence of around 20%. The reported mortality rate of microaxial LVADs was not significantly lower than extracorporeal membrane oxygenation (ECMO) or intra-aortic balloon pumps (IABP). Current evidence does not suggest any mortality benefit when compared to ECMO or IABP.

The effect of building-level socioeconomic status on bystander cardiopulmonary resuscitation: a retrospective cohort study

Background/Introduction

In out-of-hospital cardiac arrest (OHCA), bystander cardiopulmonary resuscitation (BCPR) increases survival [1]. Understanding the social determinants of BCPR receipt can inform the design of public health interventions to increase BCPR. The association of socioeconomic status (SES) with BCPR is generally poorly understood.

Purpose

We aimed to evaluate the effect of SES on BCPR in OHCA using a building-level SES marker.

Methods

This was a retrospective cohort study based on the Singapore cohort of the Pan-Asian Resuscitation Outcomes Study registry, an ongoing long-term prospective registry for OHCA in the Asia-Pacific region, between 2010 to 2018. We categorized patients into low, medium and high Singapore Housing Index (SHI) levels. The SHI, which appraises a residential property value on an ordinal scale of 1 to 7 (low to high), is a building-level marker that has a robust association with income and residence value [2]. The primary outcome was receipt of BCPR. The secondary outcomes were pre-hospital return of spontaneous circulation (ROSC) and survival – defined as survival to 30 days or hospital discharge, whichever occurred first.

Results

A total of 12,730 OHCA cases were included (Figure 1), the median age was 71 years and 58.9% were male. BCPR rate was 56.7%. OHCA patients in the low SHI tier were the youngest, most likely male, and least likely to have any medical co-morbidities (Table 1). Compared the low SHI category, those in the medium and high SHI categories were more likely to receive BCPR (medium SHI: adjusted odds ratio [aOR] 1.483, 95% CI 1.301–1.691, p&lt;0.01; high SHI: aOR 1.933, 95% CI 1.669–2.240, p&lt;0.01). As a continuous variable, every unit increase in SHI was associated with increased BCPR (aOR 1.142, 95% CI 1.110–1.174, p&lt;0.001). High SHI patients had higher survival compared to low SHI patients on unadjusted analysis (OR 1.789, 95% CI 1.080–2.964) but not adjusted analysis (adjusted for age, sex, race, witness status, arrest time, past medical history of cancer, and first arrest rhythm). There were no significant differences in the proportion of ROSC across three categories of SHI (p=0.426). When comparing high with low SHI, females had larger increases in BCPR rates compared to males (ratio of OR 1.370, 95% CI 1.012–1.853). There were no significant associations between SHI and BCPR in the subgroups age ≥65 years, witnessed arrest, daytime arrest, and arrests after 2014, and no interaction effects were observed.

Conclusions

Lower building-level SES was independently associated with lower rate of BCPR. Higher SES was associated with higher 30-day survival on unadjusted analysis but not adjusted analysis, and this study may be under-powered for this outcome. Females were more susceptible to the effect of low SES on lower rate of BCPR, and community CPR training should focus on recognizing OHCA and performing BCPR in women in low SES communities.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Medical Research Council, Clinician Scientist Awards, Singapore (NMRC/CSA/024/2010, NMRC/CSA/0049/2013 and NMRC/CSA-SI/0014/2017) and Ministry of Health, Health Services Research Grant, Singapore (HSRG/0021/2012).

Immunoassay-Compatible Inactivation of SARS-CoV-2 in Plasma Samples for Enhanced Handling Safety

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inactivation is an important step toward enhanced biosafety in testing facilities and affords a reduction in the biocontainment level necessary for handling virus-positive biological specimens. Virus inactivation methods commonly employ heat, detergents, or combinations thereof. In this work, we address the dearth of information on the efficacy of SARS-CoV-2 inactivation procedures in plasma and their downstream impact on immunoassays. We evaluated the effects of heat (56 °C for 30 min), detergent (1-5% Triton X-100), and solvent-detergent (SD) combinations [0.3-1% tri-n-butyl phosphate (TNBP) and 1-2% Triton X-100] on 19 immunoassays across different assay formats. Treatments are deemed immunoassay-compatible when the average and range of percentage recovery (treated concentration relative to untreated concentration) lie between 90-110 and 80-120%, respectively. We show that SD treatment (0.3% TNBP/1% Triton-X100) is compatible with more than half of the downstream immunoassays tested and is effective in reducing SARS-CoV-2 infectivity in plasma to below detectable levels in plaque assays. This facile method offers enhanced safety for laboratory workers handling biological specimens in clinical and research settings.

Clustering of Environmental Parameters and the Risk of Acute Myocardial Infarction

The association between days with similar environmental parameters and cardiovascular events is unknown. We investigate the association between clusters of environmental parameters and acute myocardial infarction (AMI) risk in Singapore. Using k-means clustering and conditional Poisson models, we grouped calendar days from 2010 to 2015 based on rainfall, temperature, wind speed and the Pollutant Standards Index (PSI) and compared the incidence rate ratios (IRR) of AMI across the clusters using a time-stratified case-crossover design. Three distinct clusters were formed with Cluster 1 having high wind speed, Cluster 2 high rainfall, and Cluster 3 high temperature and PSI. Compared to Cluster 1, Cluster 3 had a higher AMI incidence with IRR 1.04 (95% confidence interval 1.01–1.07), but no significant difference was found between Cluster 1 and Cluster 2. Subgroup analyses showed that increased AMI incidence was significant only among those with age ≥65, male, non-smokers, non-ST elevation AMI (NSTEMI), history of hyperlipidemia and no history of ischemic heart disease, diabetes or hypertension. In conclusion, we found that AMI incidence, especially NSTEMI, is likely to be higher on days with high temperature and PSI. These findings have public health implications for AMI prevention and emergency health services delivery during the seasonal Southeast Asian transboundary haze.

Association of High-Volume Centers With Survival Outcomes Among Patients With Nontraumatic Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

Importance

Although high volume of cases of out-of-hospital cardiac arrest (OHCA) is a key feature of cardiac arrest centers, which have proven survival benefit, the role of center volume as an independent variable associated with improved outcomes is unclear.

Objective

To assess the association of high-volume centers with survival and neurological outcomes in nontraumatic OHCA.

Data Sources

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched from inception to October 11, 2021, for studies including adult patients with nontraumatic OHCA who were treated at high-volume vs non-high-volume centers.

Study Selection

Randomized clinical trials, nonrandomized studies of interventions, prospective cohort studies, and retrospective cohort studies were selected that met the following criteria: (1) adult patients with OHCA of nontraumatic etiology, (2) comparison of high-volume with low-volume centers, (3) report of a volume-outcome association, and (4) report of outcomes of interest. At least 2 authors independently reviewed each article, blinded to each other's decision.

Data Extraction and Synthesis

Data abstraction and quality assessment were independently conducted by 2 authors. Meta-analyses were performed for adjusted odds ratios (aORs) and crude ORs using a random-effects model. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

Main Outcomes and Measures

Survival and good neurological outcomes according to the Cerebral Performance Categories Scale at hospital discharge or 30 days.

Results

A total of 16 studies involving 82 769 patients were included. Five studies defined high volume as 40 or more cases of OHCA per year; 3 studies defined high volume as greater than 100 cases of OHCA per year. All other studies differed in definitions. Survival to discharge or 30 days improved with treatment at high-volume centers, regardless of whether aORs (1.28 [95% CI, 1.00-1.64]) or crude ORs (1.43 [95% CI, 1.09-1.87]) were pooled. There was no association between center volume and good neurological outcomes at 30 days or hospital discharge in patients with OHCA (aOR, 0.96 [95% CI, 0.77-1.20]).

Conclusions and Relevance

In this meta-analysis and systematic review, care at high-volume centers was associated with improved survival outcomes, even after adjustment for potential confounders, but was not associated with improved neurological outcomes for patients with nontraumatic OHCA. More studies evaluating the relative importance of center volume compared with other variables (eg, the availability of treatment modalities) associated with survival outcomes in patients with OHCA are required.

Investigating 5-Level EQ-5D (EQ-5D-5L) Values Based on Preferences of Patients With Heart Disease

OBJECTIVES

Several studies have shown that patients with heart disease value hypothetical health states differently from the general population. We aimed to investigate the health preferences of patients with heart disease and develop a value set for the 5-level EQ-5D (EQ-5D-5L) based on these patient preferences.

METHODS

Patients with confirmed heart disease were recruited from 2 hospitals in Singapore. A total of 86 EQ-5D-5L health states (10 per patient) were valued using a composite time trade-off method according to the international valuation protocol for EQ-5D-5L; 20-parameter linear models and 8-parameter cross-attribute level effects models with and without an N45 term (indicating whether any health state dimension at level 4 or 5 existed) were estimated. Each model included patient-specific random intercepts. Model performance was evaluated for out-of-sample and in-sample predictive accuracy in terms of root mean square error. The discriminative ability of the utility values was assessed using heart disease-related functional classes.

RESULTS

A total of 576 patients were included in the analysis. The preferred model, with the lowest out-of-sample root mean square error, was a 20-parameter linear model including N45. Predicted utility values ranged from -0.727 for the worst state to 1 for full health; the value for the second-best state was 0.981. Utility values demonstrated good discriminative ability in differentiating among patients of varied functional classes.

CONCLUSIONS

An EQ-5D-5L value set representing the preferences of patients with heart disease was developed. The value set could be used for patient-centric economic evaluation and health-related quality of life assessment for patients with heart disease.

Pericarditis and myocarditis after COVID-19 mRNA vaccination in a nationwide setting

Introduction: Despite reports suggesting an association between COVID-19 mRNA vaccination and pericarditis and myocarditis, detailed nationwide population-based data are sparsely available. We describe the incidence of pericarditis and myocarditis by age categories and sex after COVID-19 mRNA vaccination from a nationwide mass vaccination programme in Singapore. Methods: The incidence of adjudicated cases of pericarditis and myocarditis following COVID-19 mRNA vaccination that were reported to the vaccine safety committee between January to July 2021 was compared with the background incidence of myocarditis in Singapore. Results: As of end July 2021, a total of 34 cases were reported (9 pericarditis only, 14 myocarditis only, and 11 concomitant pericarditis and myocarditis) with 7,183,889 doses of COVID-19 mRNA vaccine administered. Of the 9 cases of pericarditis only, all were male except one. The highest incidence of pericarditis was in males aged 12–19 years with an incidence of 1.11 cases per 100,000 doses. Of the 25 cases of myocarditis, 80% (20 cases) were male and the median age was 23 years (range 12–55 years) with 16 cases after the second dose. A higher-than-expected number of cases were seen in males aged 12–19 and 20–29 years, with incidence rates of 3.72 and 0.98 case per 100,000 doses, respectively. Conclusion: Data from the national registry in Singapore indicate an increased incidence of pericarditis and myocarditis in younger men after COVID-19 mRNA vaccination. Keywords: COVID-19 vaccine, myocarditis, pericarditis

Pericarditis and myocarditis after COVID-19 mRNA vaccination in a nationwide setting

INTRODUCTION

Despite reports suggesting an association between COVID-19 mRNA vaccination and pericarditis and myocarditis, detailed nationwide population-based data are sparsely available. We describe the incidence of pericarditis and myocarditis by age categories and sex after COVID-19 mRNA vaccination from a nationwide mass vaccination programme in Singapore.

METHODS

The incidence of adjudicated cases of pericarditis and myocarditis following COVID-19 mRNA vaccination that were reported to the vaccine safety committee between January to July 2021 was compared with the background incidence of myocarditis in Singapore.

RESULTS

As of end July 2021, a total of 34 cases were reported (9 pericarditis only, 14 myocarditis only, and 11 concomitant pericarditis and myocarditis) with 7,183,889 doses of COVID-19 mRNA vaccine administered. Of the 9 cases of pericarditis only, all were male except one. The highest incidence of pericarditis was in males aged 12-19 years with an incidence of 1.11 cases per 100,000 doses. Of the 25 cases of myocarditis, 80% (20 cases) were male and the median age was 23 years (range 12-55 years) with 16 cases after the second dose. A higher-than-expected number of cases were seen in males aged 12-19 and 20-29 years, with incidence rates of 3.72 and 0.98 case per 100,000 doses, respectively.

CONCLUSION

Data from the national registry in Singapore indicate an increased incidence of pericarditis and myocarditis in younger men after COVID-19 mRNA vaccination.

Gender disparities among adult recipients of layperson bystander cardiopulmonary resuscitation by location of cardiac arrest in Pan-Asian communities: A registry-based study

BACKGROUND

Bystander cardiopulmonary resuscitation (BCPR) is a critical component of the 'chain of survival' in reducing mortality among out-of-hospital cardiac arrest (OHCA) victims. Inconsistent findings on gender disparities among adult recipients of layperson BCPR have been reported in the literature. We aimed to fill this knowledge gap by investigating the extent of gender disparities in a cross-national setting within Pan-Asian communities.

METHODS

We utilised data collected from the Pan-Asian Resuscitation Outcomes Study (PAROS), an international, multicentre, prospective study conducted between 2009 and 2018. We included all OHCA cases with non-traumatic arrest aetiology transported by emergency medical services and excluded study sites that did not consistently collect information about the location of cardiac arrest. Logistic regression was used to analyse the association between gender and BCPR, stratified by location.

FINDINGS

We analysed a cohort of 56,192 OHCA cases with an overall BCPR rate of 36.2% (20,329/56,192). At public locations, the BCPR rate was 31.2% (631/2022) for female and 36.4% (3235/8892) for male OHCA victims; while at home, the rate was 38.3% (6838/17,842) for females and 35.1% (9625/27,436) for males. Controlling for site differences and several factors in multivariable logistic regression, we found females less likely to receive BCPR than males in public locations (odds ratio [OR]=0.89, 95% confidence interval [CI]: 0.70-0.99), but more likely to receive BCPR at home (OR=1.16, 95% CI: 1.11-1.21).

INTERPRETATION

In Pan-Asian communities, gender differences exist in adult recipients of BCPR and differ between home and public locations. Future studies should account for additional information on bystanders and societal factors to identify targets for interventions.

FUNDING

The study was supported by grants from the National Medical Research Council (NMRC/CSA/0049/2013) and Laerdal Foundation (20040).

Early Coronary Angiography Is Associated with Improved 30-Day Outcomes among Patients with Out-of-Hospital Cardiac Arrest

We evaluated the association between early coronary angiography (CAG) and outcomes in resuscitated out-of-hospital cardiac arrest (OHCA) patients, by linking data from the Singapore Pan-Asian Resuscitation Outcomes Study, with a national registry of cardiac procedures. The 30-day survival and neurological outcome were compared between patients undergoing early CAG (within 1-calender day), versus patients not undergoing early CAG. Inverse probability weighted estimates (IPWE) adjusted for non-randomized CAG. Of 976 resuscitated OHCA patients of cardiac etiology between 2011–2015 (mean(SD) age 64(13) years, 73.7% males), 337 (34.5%) underwent early CAG, of whom, 230 (68.2%) underwent PCI. Those who underwent early CAG were significantly younger (60(12) vs. 66(14) years old), healthier (42% vs. 59% with heart disease; 29% vs. 44% with diabetes), more likely males (86% vs. 67%), and presented with shockable rhythms (69% vs. 36%), compared with those who did not. Early CAG with PCI was associated with better survival and neurological outcome (adjusted odds ratio 1.91 and 1.82 respectively), findings robust to IPWE adjustment. The rates of bleeding and stroke were similar. CAG with PCI within 24 h was associated with improved clinical outcomes after OHCA, without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.

High prevalence of central hypothyroidism among patients with transfusion dependent thalassemia in Hospital Pulau Pinang: A cross sectional study

INTRODUCTION

Thalassemia is the most common heritable haematological disorder in Malaysia. Hypothyroidism is one of the complications of the transfusion dependent thalassemia (TDT) patients as a result of iron overload.

MATERIALS AND METHODS

All registered TDT patients attending Haematology day care, Hospital Pulau Pinang from January 2019 to January 2020 were included in the study. Hypothyroidism was defined according to TSH and FT4, or based on the history of treatment for diagnosed hypothyroidism.

RESULTS

There were 51 TDT patients, with 24 (47%) males and 27 (53%) females. Most of the patients were Malays (27, 53%) followed with Chinese (23, 45%) and Indonesian (1, 2%). Beta thalassemia major and HbE beta thalassaemia accounted for 35 (68.8%) and 14 (27.5%) TDT patients respectively, while two (3.9%) were HbH Constant Spring. Eleven (21.6%) had hypothyroidism; of which seven (63.6%) had central hypothyroidism, three (27.3%) had subclinical hypothyroidism, the remaining one (9.1%) had primary hypothyroidism. Three (27.3%) had concomitant hypogonadism, one (9.1%) had hypocortisolism and another (9.1%) had both diabetes mellitus and hypogonadism. There was no statistical relationship between the prevalence of hypothyroidism and age, serum ferritin, splenectomy history and iron chelation therapy.

CONCLUSION

High prevalence of central hypothyroidism is reported. Measurement of both TSH and FT4 is recommended as initial screening for thyroid dysfunction among patient with TDT.

Incidence, characteristics and complications of dispatcher-assisted cardiopulmonary resuscitation initiated in patients not in cardiac arrest

AIM

Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) can increase bystander CPR rates and improve outcomes in out-of-hospital cardiac arrest (OHCA). Despite the use of protocols, dispatchers may falsely recognise some cases to be in cardiac arrest. Hence, this study aimed to find the incidence of DA-CPR initiated for non-OHCA cases, its characteristics and clinical outcomes in the Singapore population.

METHODS

This was a multi-centre, observational study of all dispatcher-recognised cardiac arrests cases between January to December 2017 involving three tertiary hospitals in Singapore. Data was obtained from the Pan-Asian Resuscitation Outcomes Study cohort. Audio review of dispatch calls from the national emergency ambulance service were conducted and information about patients' clinical outcomes were prospectively collected from health records. Univariate analysis was performed to determine factors associated with in-hospital mortality among non-OHCA patients who received DA-CPR.

RESULTS

Of the 821 patients recognised as having OHCA 328 (40.0%) were not in cardiac arrest and 173 (52.7%) of these received DA-CPR. No complications from chest compressions were found from hospital records. The top diagnoses of non-OHCA patients were cerebrovascular accidents (CVA), syncope and infection. Only final diagnoses of CVA (aOR 20.68), infection (aOR 17.34) and myocardial infarction (aOR 32.19) were significantly associated with in-hospital mortality.

CONCLUSION

In this study, chest compressions initiated on patients not in cardiac arrest by dispatchers did not result in any reported complications and was not associated with in-hospital mortality. This provides reassurance for the continued implementation of DA-CPR.

Beyond return of spontaneous circulation: update on post-cardiac arrest management in the intensive care unit

A well-functioning chain of survival is critical for good outcomes following out-of-hospital cardiac arrest, a major public health concern in Singapore. While the percentage of survivors to hospital admission has increased over the years, the percentage of survivors to hospital discharge and the number of patients with good neurological recovery can be greatly improved. This underscores the urgent need to focus on 'post-cardiac arrest care', the fifth link in the chain of survival, to improve the outcomes of patients who are admitted to the intensive care unit (ICU) after return of spontaneous circulation. This review builds on earlier recommendations of the Singapore National Targeted Temperature Management Workgroup in 2017 to provide a focused update on post-cardiac arrest management and a practical guide for physicians managing resuscitated patients with cardiac arrest in the ICU.

Assessing unrealised potential for organ donation after out-of-hospital cardiac arrest

BACKGROUND

Organ donation after brain death is the standard practice in many countries. Rates are low globally. This study explores the potential national number of candidates for uncontrolled donations after cardiac death (uDCD) amongst out-of-hospital cardiac arrest (OHCA) patients and the influence of extracorporeal cardiopulmonary resuscitation (ECPR) on the candidacy of these potential organ donors using Singapore as a case study.

METHODS

Using Singapore data from the Pan-Asian Resuscitation Outcomes Study, we identified all non-traumatic OHCA cases from 2010 to 2016. Four established criteria for identifying uDCD candidates (Madrid, San Carlos Madrid, Maastricht and Paris) were retrospectively applied onto the population. Within these four groups, a condensed ECPR eligibility criteria was employed and thereafter, an estimated ECPR survival rate was applied, extrapolating for possible neurologically intact survivors had ECPR been administered.

RESULTS

12,546 OHCA cases (64.8% male, mean age 65.2 years old) qualified for analysis. The estimated number of OHCA patients who were eligible for uDCD ranged from 4.3 to 19.6%. The final projected percentage of potential uDCD donors readjusted for ECPR survivors was 4.2% (Paris criteria worst-case scenario, n = 532) to 19.4% of all OHCA cases (Maastricht criteria best-case scenario, n = 2428), for an estimated 14.3 to 65.4 uDCD donors per million population per year (pmp/year).

CONCLUSIONS

In Singapore case study, we demonstrated the potential numbers of candidates for uDCD among resuscitated OHCA cases. This sizeable pool of potential donors demonstrates the potential for an uDCD program to expand the organ donor pool. A small proportion of these patients might however survive had they been administered ECPR. Further research into the factors influencing local organ and patient outcomes following uDCD and ECPR is indicated.

Subclinical vasculopathy and skeletal muscle metrics in the singapore longitudinal ageing study

Frailty is associated with future cardiovascular events in older adults. This cross-sectional study examined the relationship between subclinical vasculopathy with measures of skeletal muscle mass and function. Asymptomatic community-dwelling Asians ≥55 years underwent assessments for subclinical vasculopathy (carotid intima-media thickness (cIMT), aortic and carotid stiffness, and endothelial function), muscle mass (calf circumference adjusted for body mass index) and function (knee extension strength, 6-meter fast gait speed). Multivariable regression analyses for associates of muscle mass/function controlled for demographics and cardiometabolic risk factors. Among 336 participants (median age 62 years, 55.1% male, 3.6% sarcopenia), cIMT, aortic and carotid stiffness inversely correlated with muscle mass, strength and gait speed; cIMT remained independently associated with gait speed (β=-0.26) in multivariable analyses. Age and sex significantly modified the relationship between subclinical vasculopathy and muscle mass/function. Associations, only found in those aged ≥70, included cIMT with gait speed (β=-0.48) and knee strength (β=-9.33), and aortic augmentation index and aortic stiffness composite z-score with gait speed (β=-0.11 and β=-0.19 respectively). Among males, cIMT correlated with gait speed (β=-0.31). The association of subclinical vasculopathy with skeletal muscle mass and function in asymptomatic adults ≥55 years is best reflected by cIMT. The roles of mediating pathways deserve further evaluation.

Cost-effectiveness of prenatal screening methods for congenital heart defects in pregnancies conceived by in-vitro fertilization

OBJECTIVES

To determine if a policy of universal fetal echocardiography (echo) in pregnancies conceived by in-vitro fertilization (IVF) is cost-effective as a screening strategy for congenital heart defects (CHDs) and to examine the cost-effectiveness of various other CHD screening strategies in IVF pregnancies.

METHODS

A decision-analysis model was designed from a societal perspective with respect to the obstetric patient, to compare the cost-effectiveness of three screening strategies: (1) anatomic ultrasound (US): selective fetal echo following abnormal cardiac findings on detailed anatomic survey; (2) intracytoplasmic sperm injection (ICSI) only: fetal echo for all pregnancies following IVF with ICSI; (3) all IVF: fetal echo for all IVF pregnancies. The model initiated at conception and had a time horizon of 1 year post-delivery. The sensitivities and specificities for each strategy, the probabilities of major and minor CHDs and all other clinical estimates were derived from the literature. Costs, including imaging, consults, surgeries and caregiver productivity losses, were derived from the literature and Medicare databases, and are expressed in USA dollars ($). Effectiveness was quantified as quality-adjusted life years (QALYs), based on how the strategies would affect the quality of life of the obstetric patient. Secondary effectiveness was quantified as number of cases of CHD and, specifically, cases of major CHD, detected.

RESULTS

The average base-case cost of each strategy was as follows: anatomic US, $8119; ICSI only, $8408; and all IVF, $8560. The effectiveness of each strategy was as follows: anatomic US, 1.74487 QALYs; ICSI only, 1.74497 QALYs; and all IVF, 1.74499 QALYs. The ICSI-only strategy had an incremental cost-effectiveness ratio (ICER) of $2 840 494 per additional QALY gained when compared to the anatomic-US strategy, and the all-IVF strategy had an ICER of $5 692 457 per additional QALY when compared with the ICSI-only strategy. Both ICERs exceeded considerably the standard willingness-to-pay threshold of $50 000-$100 000 per QALY. In a secondary analysis, the ICSI-only strategy had an ICER of $527 562 per additional case of major CHD detected when compared to the anatomic-US strategy. All IVF had an ICER of $790 510 per case of major CHD detected when compared with ICSI only. It was determined that it would cost society five times more to detect one additional major CHD through intensive screening of all IVF pregnancies than it would cost to pay for the neonate's first year of care.

CONCLUSION

The most cost-effective method of screening for CHDs in pregnancies following IVF, either with or without ICSI, is to perform a fetal echo only when abnormal cardiac findings are noted on the detailed anatomy scan. Performing routine fetal echo for all IVF pregnancies is not cost-effective. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Artificial Intelligence Applications for COVID-19 in Intensive Care and Emergency Settings: A Systematic Review

Background: Little is known about the role of artificial intelligence (AI) as a decisive technology in the clinical management of COVID-19 patients. We aimed to systematically review and critically appraise the current evidence on AI applications for COVID-19 in intensive care and emergency settings. Methods: We systematically searched PubMed, Embase, Scopus, CINAHL, IEEE Xplore, and ACM Digital Library databases from inception to 1 October 2020, without language restrictions. We included peer-reviewed original studies that applied AI for COVID-19 patients, healthcare workers, or health systems in intensive care, emergency, or prehospital settings. We assessed predictive modelling studies and critically appraised the methodology and key findings of all other studies. Results: Of fourteen eligible studies, eleven developed prognostic or diagnostic AI predictive models, all of which were assessed to be at high risk of bias. Common pitfalls included inadequate sample sizes, poor handling of missing data, failure to account for censored participants, and weak validation of models. Conclusions: Current AI applications for COVID-19 are not ready for deployment in acute care settings, given their limited scope and poor quality. Our findings underscore the need for improvements to facilitate safe and effective clinical adoption of AI applications, for and beyond the COVID-19 pandemic.

Impact of COVID-19 on Out-of-Hospital Cardiac Arrest in Singapore

This study aimed to evaluate the impact of the Coronavirus Disease 2019 (COVID-19) pandemic on out-of-hospital cardiac arrest (OHCA) in Singapore. We used data from the Singapore Civil Defence Force to compare the incidence, characteristics and outcomes of all Emergency Medical Services (EMS)-attended adult OHCA during the pandemic (January-May 2020) and pre-pandemic (January-May 2018 and 2019) periods. Pre-hospital return of spontaneous circulation (ROSC) was the primary outcome. Binary logistic regression was used to calculate the adjusted odds ratios (aOR) for the characteristics of OHCA. Of the 3893 OHCA patients (median age 72 years, 63.7% males), 1400 occurred during the pandemic period and 2493 during the pre-pandemic period. Compared with the pre-pandemic period, OHCAs during the pandemic period more likely occurred at home (aOR: 1.48; 95% CI: 1.24-1.75) and were witnessed (aOR: 1.71; 95% CI: 1.49-1.97). They received less bystander CPR (aOR: 0.70; 95% CI: 0.61-0.81) despite 65% of witnessed arrests by a family member, and waited longer for EMS (OR ≥ 10 min: 1.71, 95% CI 1.46-2.00). Pre-hospital ROSC was less likely during the pandemic period (aOR: 0.67; 95% CI: 0.53-0.84). The pandemic saw increased OHCA incidence and worse outcomes in Singapore, likely indirect effects of COVID-19.

Multiplexed Single-Cell Leukocyte Enzymatic Secretion Profiling from Whole Blood Reveals Patient-Specific Immune Signature

Enzymatic secretion of immune cells (leukocytes) plays a dominant role in host immune responses to a myriad of biological triggers, including infections, cancers, and cardiovascular diseases. Current tools to probe these leukocytes inadequately profile these vital biomarkers; the need for sample preprocessing steps of cell lysis, labeling, washing, and pipetting inevitably triggers the cells, changes its basal state, and dilutes the individual cell secretion in bulk assays. Using a fully integrated system for multiplexed profiling of native immune single-cell enzyme secretion from 50 μL of undiluted blood, we eliminate sample handling. With a total analysis time of 60 min, the integrated platform performs six tasks of leukocyte extraction, cell washing, fluorescent enzyme substrate mixing, single-cell droplet making, droplet incubation, and real-time readout for leukocyte secretion profiling of neutrophil elastase, granzyme B, and metalloproteinase. We calibrated the device, optimized the protocols, and tested the leukocyte secretion of acute heart failure (AHF) patients at admission and predischarge. This paper highlights the presence of single-cell enzymatic immune phenotypes independent of CD marker labeling, which could potentially elucidate the innate immune response states. We found that patients recovering from AHF showed a corresponding reduction in immune-cell enzymatic secretion levels and donor-specific enzymatic signatures were observed, which suggests patient-to-patient heterogeneous immune response. This platform presents opportunities to elucidate the complexities of the immune response from a single drop of blood and bridge the current technological, biological, and medical gap in understanding immune response and biological triggers.