Context-aware deep network for coronary artery stenosis classification in coronary CT angiography

Automatic coronary artery stenosis grading plays an important role in the diagnosis of coronary artery disease. Due to the difficulty of learning the informative features from varying grades of stenosis, it is still a challenging task to identify coronary artery stenosis from coronary CT angiography (CCTA). In this paper, we propose a context-aware deep network (CADN) for coronary artery stenosis classification. The proposed method integrates 3D CNN with Transformer to improve the feature representation of coronary artery stenosis in CCTA. We evaluate the proposed method on a multicenter dataset (APOLLO study with NCT05509010). Experimental results show that our proposed method can achieve the accuracy of 0.84, 0.83, and 0.86 for stenosis diagnosis on the lesion, artery, and patient levels, respectively.

Acute myocardial infarction and myocarditis following COVID-19 vaccination

Emerging reports raise concerns on the potential association between the COVID-19 vaccines and cardiac manifestations. We sought to evaluate cardiac complications associated with COVID-19 vaccination in a pooled analysis from our institution's cohort study and systematic review. Consecutive patients admitted to a tertiary hospital in Singapore between 1 January 2021 and 31 March 2021, with the onset of cardiac manifestations within 14 days following COVID-19 vaccination, were studied. Furthermore, a systematic review was performed, with PubMed, Embase, Research Square, MedRxiv and LitCovid databases accessed from inception up to 29 June 2021. Relevant manuscripts reporting individual patient data on cardiac complications following COVID-19 vaccination were included. Thirty patients were included in the study cohort, with 29 diagnosed with acute myocardial infarction (AMI) and 1 with myocarditis. Five patients developed heart failure, two had cardiogenic shock, three intubated, and one had cardiovascular-related mortality. In the systematic review, 16 studies were included with 41 myocarditis and 6 AMI cases. In the pooled analysis of the study cohort and the systematic review, 35 patients had AMI and 42 had myocarditis. Majority were men, and myocarditis patients were younger than AMI patients. Myocarditis patients tended to present 72 h postvaccination, while AMI patients were older and typically presented 24 h postvaccination. Majority with AMI or myocarditis developed symptoms after the first and second vaccination dose, respectively. This pooled analysis of patients presenting with cardiac manifestations following COVID-19 vaccination highlights the differences between myocarditis and AMI presentations in temporal association with the vaccination.

Abnormal left atrial strain is associated with eventual diagnosis of atrial fibrillation in patients with embolic stroke of undetermined source

Funding Acknowledgements

Type of funding sources: None.

Background

Patients with embolic stroke of undetermined source (ESUS) have no immediate attributable cause despite initial evaluation. Occult paroxysmal atrial fibrillation (pAF) diagnosed on prolonged electrocardiographic monitoring may be subsequently found in 20% of patients initially classified as ESUS [1]. Anatomic and functional alterations of left atrium (LA) are known to predict pAF in the general population [2]. Recent studies have suggested that LA dysfunction is linked to the risk of development of pAF in stroke patients and may precede LA enlargement [1]. LA strain analysis may be helpful to predict the development of pAF as it can detect subclinical functional impairment [2]. The aim of this study was to analyse whether LA strain can be a marker for the development of new-onset AF in patients with ESUS and sinus rhythm.

Methods

Our single-centre observational cohort study examined 157 patients hospitalised for ESUS in our tertiary hospital between October 2014 and October 2017 who underwent AF monitoring with an implantable loop recorder (ILR). These patients were followed up for occurrence of new-onset pAF and recurrence of ischaemic stroke. All patients underwent transthoracic echocardiography (TTE) during index hospitalisation as part of the workup for ESUS. Echocardiographic images were obtained and analysed post-hoc for two-dimensional (2D) speckle tracing deformation parameters. These LA strain parameters were analysed against the primary outcome of AF detection and secondary outcome of recurrent ischaemic stroke.

Results

A total of 157 ESUS patients, with a mean age of 61.0 (±11.6) years, were followed up for a median duration of 3.5 (interquartile range 3.29) years. ILR monitoring detected AF in 27 patients (17.2%). 27 patients developed recurrent ischaemic strokes. Of the 27 patients with newly diagnosed AF on ILR, 24 (88.9%) were commenced on oral anticoagulation; the remaining 3 patients were not on anticoagulation due to high bleeding risk and frailty.

Patients who had newly diagnosed AF had more impaired left atrial reservoir strain (LASr; 23.5% ± 10.3%, P = 0.042) and left atrial conduit strain (LAScd; -10.5% ± 5.3%, P = 0.003) compared with patients who remained in sinus rhythm. Multivariable logistic regression analysis adjusting for age, sex, hypertension, hyperlipidaemia, diabetes mellitus and left ventricular ejection fraction (LVEF) showed that LAScd was associated with occult AF (adjusted odds ratio [aOR] = 1.110, 95% CI, 1.019-1.209, P = 0.017) and the composite outcome of AF and recurrent ischaemic stroke (OR = 1.069, 95% CI, 1.014-1.138, P = 0.038). Abnormal LAScd was significantly associated with occult AF even when stratified by normal LA volume index (LAVI) (OR = 2.672, 95% CI, 1.035-8.548, P = 0.048) and high LAVI (OR = 1.713, 95% CI, 1.023-2.869, P = 0.041).

Conclusion

Impaired left atrial strain was associated with occult AF detection in patients with ESUS undergoing ILR monitoring.

Higher risk of adverse cardiovascular outcomes in women with type 2 diabetes mellitus: an umbrella review of systematic reviews

Funding Acknowledgements

Type of funding sources: None.

Background

Previous studies have shown that females with type 2 diabetes mellitus (T2DM) may have an excess mortality risk compared to males. Furthermore, other studies have reported sex differences in managing cardiovascular risk factors, such as controlling hypertension and hypercholesterolemia.

Purpose

With the growing evidence from systematic reviews examining the sex differences in cardiovascular outcomes for patients with T2DM, an umbrella review is an essential next step to synthesising and assessing the strength of the available evidence.

Methods

Medline and Embase were searched from inception till 7th August 2022 for systematic reviews and meta-analyses studying the effects of sex on cardiovascular outcomes in T2DM patients. Results from reviews were synthesised with a narrative synthesis, with a tabular presentation of findings and forest plots for reviews that performed a meta-analysis. AMSTAR 2 tool was used to assess the methodological quality of included reviews, while the GRADE assessment was used to assess the quality of evidence for outcomes.

Results

A total of 28 studies evaluating sex differences in cardiovascular outcomes were included. Females with T2DM had a higher risk of developing coronary heart disease (CHD; RRR 1.52, 95%CI 1.32–1.76, p<0.001), acute coronary syndrome (ACS; RRR 1.38, 95%CI 1.25–1.52, p<0.001), and heart failure (RRR 1.09, 95%CI 1.05–1.13, p<0.001) than males. In terms of mortality outcomes, females had a higher risk of all-cause mortality (RRR 1.13, 95%CI 1.07–1.19, p<0.001), cardiac mortality (RRR 1.49, 95%CI 1.11–2.00, p=0.009) and CHD mortality (RRR 1.44, 95%CI 1.20–1.73, p<0.001) as compared to males. In patients undergoing percutaneous coronary intervention, females reported higher odds of MACE (OR 1.49, 95%CI 1.07–2.07, p=0.020) and all-cause mortality (OR 1.71, 95%CI 1.46–2.00, p<0.001) compared to males. Females in Asia (RRR 1.12, 95%CI 1.03–1.21, p=0.006) and North America (RRR 1.10, 95%CI 1.08–1.12, p<0.001) were at increased risk of all-cause mortality while females in Western countries had an increased risk for cardiac death (RRR 1.84, 95%CI 1.45–2.32, p<0.001) compared to males. Six reviews were rated as high in quality; eight reviews were rated as moderate, and fourteen reviews were rated as low in quality. Regarding the quality of outcomes, all outcomes in non-interventional studies had a moderate quality of evidence, while all outcomes in interventional studies achieved a high quality of evidence.

Conclusions

This umbrella review evaluated the quality of meta-analyses and demonstrated that females with T2DM have a higher risk of cardiovascular outcomes than their male counterparts. Future studies examining the sex differences in outcomes should attempt to address the heterogeneity and epidemiological factors for a better quality of evidence. Policymakers should consider sex-specific differences in implementing effective tailored strategies to tackle T2DM.

Effects of epicardial adipose tissue volume and thickness assessed by computed tomography and echocardiography on cardiovascular and cerebrovascular outcomes: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Epicardial adipose tissue (EAT) has garnered attention as a potential imaging biomarker for the risk stratification of cardiovascular diseases (CVD). However, the prognostic utility of EAT due to inter-ethnic differences and imaging modality (computed tomography (CT) or transthoracic echocardiography (TTE)) remains undetermined.

Purpose

To evaluate the effect of EAT volume and thickness on cardiovascular and cerebrovascular outcomes. We also aim to compare the prognostic utility between CT volumetric and TTE thickness quantification; and provide consolidated data on the heterogeneity in EAT measurements across different ethnic groups.

Methods

Medline and Embase databases were searched from inception till 16 May 2022 for studies that measured EAT volume or thickness of adult patients at baseline and reported follow-up data on outcomes of interest. Outcomes included MACE, all-cause mortality, cardiac death, myocardial infarction (MI), coronary revascularisation, atrial fibrillation (AF), and stroke. Statistical analyses were conducted on Review Manager 5.4.1 to obtain unadjusted and adjusted hazard ratios (HR) and odds ratios (OR) with the results presented on forest plots.

Results

Twenty-nine studies comprising 19709 patients were included in our analysis. Increased EAT thickness and volume were associated with higher risks of MACE (adjusted HR [aHR] 1.46, 95%CI 1.25–1.71, p<0.001), cardiac death (OR 2.53, 95%CI 1.17–5.44, p=0.020), MI (OR 2.63, 95%CI 1.39–4.96, p=0.003), coronary revascularisation (OR 2.99, 95%CI 1.64–5.44, p<0.001), AF (aOR 4.04, 95%CI 3.06–5.32, p<0.001), and stroke (HR 1.02, 95%CI 1.01–1.03, p<0.001). CT-volumetric quantification of EAT conferred a larger MACE risk (aHR 1.79, 95%CI 1.47–2.17, p<0.001) compared to TTE thickness quantification (aHR 1.20, 95%CI 1.09–1.32, p<0.001). Studies originating from North America (HR 1.91, 95%CI 1.26–2.89, p=0.002) and Asia (HR 1.60, 95%CI 1.09–2.36, p=0.020) demonstrated a significantly higher risk of MACE with increased EAT thickness and volume. However, this significance was not seen in European studies (HR 1.48, 95%CI 0.99–2.20, p=0.060). Subgroup differences were also noted across the studies’ countries of origin when analysing the association of EAT and MI (p=0.020). European studies reported a higher magnitude of MI risk associated with higher EAT thickness and volume (OR 5.28, 95%CI 2.34–11.95, p<0.001) as compared to Asian studies (OR 1.75, 95%CI 1.05–2.92, p=0.030). No differences were noted across other outcomes in the subgroup comparisons by geographical region and between CT and TTE quantification of EAT.

Conclusion

The utility of EAT as an imaging biomarker for predicting and prognosticating CVD is promising. Future efforts to harmonise the EAT parameter thresholds, based on the type of imaging modality and the target population’s ethnic characteristics, will be the next important step before including EAT in CVD prediction models.

Metabolic associated fatty liver disease increases risk of adverse events after acute coronary syndrome

 

Metabolic Associated Fatty Liver Disease (MAFLD) was recently introduced as an alternative definition for fatty liver, that has been linked to an increased risk of systemic end-organ damage. However, current studies have not examined the impact of MAFLD on patients presenting with acute coronary syndrome (ACS). Here, we present a retrospective analysis on the short and long-term outcomes of ACS patients with MAFLD.

Methods

A retrospective analysis was conducted in a tertiary care centre. Hepatic steatosis and fibrosis was examined with hepatic steatosis index and fibrosis-4 (FIB-4) index. The primary and secondary outcomes of the analysis were long term all-cause mortality, and in-hospital all-cause mortality, stroke, heart failure and cardiogenic shock respectively. Adjusted analysis was conducted for primary and secondary outcomes with covariates including age, sex, race, type of ACS and previous myocardial infarction.

Results

A total of 5770 patients were included in the analysis, and 21% of ACS patients had concomitant MAFLD. MAFLD resulted in a 23% increase in long-term all-cause mortality compared to non-MAFLD (HR: 1.230, CI: 1.065 to 1.420, p=0.005). MAFLD increased the risk of in-hospital mortality, stroke, heart failure and cardiogenic shock compared to non-MAFLD. A sensitivity analysis conducted based on MAFLD with advance fibrosis, chronic kidney disease and diabetes also demonstrated significantly increased effect size magnitude of all-cause mortality, compared to non-MAFLD.

Conclusion

MAFLD represents an encapsulation of metabolism dysregulation and has been associated with increased risk of systematic disease. The present study shows that MAFLD is associated with significantly increased adverse prognostic outcomes after ACS compared to non-MAFLD. An increase in awareness of MAFLD is required beyond the field of hepatology for improvements in multidisciplinary care and management.

Funding Acknowledgement

Type of funding sources: None.

Reconstructed meta-analysis of percutaneous coronary intervention versus coronary artery bypass grafting for left main disease

Background

Randomized controlled trials (RCTs) comparing percutaneous coronary intervention (PCI) with drug-eluting stents and coronary artery bypass grafting (CABG) for patients with left main coronary artery disease (LMCAD) have reported conflicting results.

Objectives

We performed a systematic review from inception to 23 May 2021 and one-stage reconstructed individual-patient data meta-analysis (IPDMA) that included 10-year mortality outcomes.

Methods

The primary outcome was 10-year all-cause mortality. Secondary outcomes included myocardial infarction (MI), stroke and unplanned revascularization at 5 years. We did IPDMA using published Kaplan-Meier curves to provide individual data points in coordinates and numbers at risk were used to increase the calibration accuracy of the reconstructed data. Shared frailty model or, when proportionality assumptions were not met, a restricted mean survival time model were fitted to compare outcomes between treatment groups.

Results

Of 583 articles retrieved, 5 RCTs were included. A total of 4595 patients from these 5 RCTs were randomly assigned to PCI (N=2297) or CABG (N=2298). The cumulative 10-year all-cause mortality after PCI and CABG was 12.0% versus 10.6% respectively (HR 1.093, 95% CI: 0.925–1.292; p=0.296). PCI conferred similar time-to-MI (RMST ratio 1.006, 95% CI: 0.992–1.021, p=0.391) and stroke (RMST ratio 1.005, 95% CI: 0.998–1.013, p=0.133) at 5 years. Unplanned revascularization was more frequent following PCI compared with CABG (HR 1.807, 95% CI: 1.524–2.144, p<0.001) at 5 years.

Conclusion

This meta-analysis using reconstructed participant-level time-to-event data showed no statistically significant difference in cumulative 10-year all-cause mortality between PCI versus CABG in the treatment of LMCAD.

Funding Acknowledgement

Type of funding sources: None.

Coronary artery bypass grafting versus percutaneous coronary intervention with stenting for multivessel coronary artery disease without left main coronary disease:reconstructed individual patient data

Background and aims

Data are emerging on 10-year mortality comparing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) with stenting for multivessel disease (MVD) without left main (LM) involvement. We conducted an updated two-stage meta-analysis using reconstructed individual patient data to compare long-term mortality between CABG and PCI for patients with MVD without significant LM coronary disease.

Methods

Medline and Embase databases were searched for articles comparing CABG with PCI for MVD. A two-stage meta-analysis was conducted using reconstructed patient level survival data for all-cause mortality with subgroups by SYNTAX score. The shared-frailty and stratified Cox models were fitted to compare survival endpoints.

Results

We screened 1496 studies and included six randomized controlled trials with 7181 patients. PCI was associated with greater 10-year all-cause mortality risk (HR: 1.282, CI: 1.118–1.469, p<0.001) compared with CABG. In patients with low SYNTAX score, 10-year all-cause mortality after PCI was comparable to CABG (HR: 1.102, 0.822–1.479, p=0.516). However, in patients with moderate to high SYNTAX score, 10-year all-cause mortality was significantly higher after PCI compared with CABG (HR: 1.444, 1.122–1.858, p<0.001; HR: 1.856, 1.380–2.497, p<0.001 respectively).

Conclusion

This updated reconstructed individual patient-data meta-analysis revealed a sustained lower cumulative all-cause mortality of CABG over PCI for multivessel disease without LM involvement.

Funding Acknowledgement

Type of funding sources: None.

Spatial-temporal lipidomics profile of acute myocardial injury

Background

Lipidome disturbance has long been recognized to occur after myocardial infarction (MI). Accumulation of excessive fatty acids induces production of reactive oxygen species and consequently deteriorates cardiac injury in MI. However, the spatial and temporal lipid profile in the heart following ischemic injury remains unknown.

Purpose

We aim to uncover the temporal-spatial lipidome profile of the heart following ischemia reperfusion (I/R) injury and identify circulating lipids released from injured myocardium that are potentially useful for diagnosis of ischemic heart disease.

Methods

C57/BL6 mice were subjected to 30 min myocardial ischemia followed by removal of the ligature to establish reperfusion injury. Porcine I/R injury was induced by 105 min myocardial ischemia followed by reperfusion. Human plasma was obtained from 143 post-MI patients. Myocardial lipid profiles were generated by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MALDI-MSI) in different regions (infarct, remote and peri-infarct) at different time points. Moreover, the lipids in the heart and plasma were analysed by LC-MS/MS.

Results

We observed a drastic alteration in the lipidome with distinct spatial-temporal features in the injured heart by both MALDI-MSI and LC-MS/MS. In the infarct heart tissue, as revealed by LC-MS/MS, we observed an elevation of glycerolipids that peaked at 3 hours after I/R, and a sustained elevation of phospholipids and sphingolipids up to 3 days. Similar alternations in lipid profile was observed but much weaker in the remote and peri-infarct heart tissue compared to the infarct tissue. Among those lipids, PC 32:0 detected by MALDI-MSI highly overlapped CD68 staining at a single-cell level, showing a strong correlation of PC 32:0 with macrophage infiltration in mouse hearts (R2=0.93, p<0.0001). A similar increase of PC 32:0 in the infarct area was also observed in porcine hearts following I/R injury. Surprisingly, plasma levels of PC 32:0 in the mice decreased after I/R injury. In humans, plasma levels of PC 32:0 in post-MI patients were lower than that in healthy individuals (p=0.03). Further analysis demonstrated that plasma levels of PC 32:0 determined within 72 hours after percutaneous coronary intervention were negatively correlated with the 6-month post-MI cardiac ejection fraction in patients (R2=0.08, p<0.001).

Conclusions

A temporal-spatial lipidome profile was established in heart injury by synergizing LC-MS/MS and mass spectrometry imaging. PC 32:0 levels are positively correlated with myocardial macrophage infiltration but negatively correlated with cardiac function in cardiac I/R injury. Our findings indicate that PC 32:0 is a potential biomarker for cardiac injury and the inflammatory status in the injured heart.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Singapore Ministry of Health's National Medical Research Council

A 10-year cohort on prognostic outcomes in patients presenting with acute myocardial infarction complicated by cardiogenic shock and/or cardiac arrest

Background

Cardiogenic shock (CS) and cardiac arrest (CA) complicating acute myocardial infarction (AMI) portend unfavourable outcomes. This study examined the prognosis of patients presenting with AMI complicated by CS and/or CA.

Methods

Consecutive patients presented with AMI to a percutaneous coronary intervention-capable tertiary institution between 2011 and 2021 were studied. Patients were stratified based on the presence or absence of CS (CS+ or CS−) and CA (CA+ or CA−). The primary outcome was 30-day cardiovascular-related mortality. Subgroup analyses based on AMI-type and sex were conducted. Kaplan-Meier curves for cardiovascular-related mortality based on the AMI-type and sex were constructed.

Results

The study included 11,608 AMI patients, 283 of whom had CS+/CA+, 1,068 had CS+/CA−, 54 had CS−/CA+ and 10,203 had CS−/CA−. Cardiovascular-related mortality was significantly higher for CS+/CA+ (57.6%), followed by CS+/CA− (41.6%), CS−/CA+ (20.4%) and CS−/CA− (2.4%). Kaplan-Meier curves demonstrated CS+/CA+ group had the highest mortality (HR=36.26; 95% CI: 29.71–44.25, p<0.001), followed by CS+/CA− (HR=21.59; 95% CI: 18.47–25.24, p<0.001) and CS−/CA+ (HR=9.18; 95% CI: 5.02–16.80, p<0.001), with CS−/CA− as the reference. Those with NSTEMI had consistently higher cardiovascular-related mortality rates than their STEMI counterparts for all groups, apart from the CS+/CA+ group. The sex-specific analysis demonstrated that the survival curves for females with CS+/CA+, CS+/CA− and CS−/CA+ converged, whilst the survival curves for males diverged over time. The multivariable Cox regression revealed the presence of CS and CA are independent predictors of cardiovascular-related mortality, but not NSTEMI, when adjusted for age, gender, diabetes, left ventricular ejection fraction, chronic renal failure, and culprit vessel.

Conclusions

AMI associated with CA and CS portends the least favourable survival, followed by those with CS or CA alone. Excess mortality was observed in the traditionally perceived lower-risk groups, particularly in women. This calls for increased awareness amongst clinicians when managing this subset of high-risk patients.

Funding Acknowledgement

Type of funding sources: None.

Higher long-term mortality in patients with concomitant acute coronary syndrome and aortic stenosis

Background

Aortic stenosis (AS) and acute coronary syndrome (ACS) share similar cardiovascular risk factors, and their concomitant presentation is increasing in incidence with the aging population. Yet literature regarding the prognosis of patients with concomitant ACS and AS remains scarce.

Methods

This retrospective cohort study examined consecutive patients presenting with ACS (ST-segment elevation myocardial infarction [STEMI] and non-STEMI [NSTEMI]) and concomitant AS between 1 January 2011 and 31 March 2021 in a tertiary hospital. The cohort was divided into mild, moderate and severe AS based on index echocardiogram. The primary outcome was all-cause mortality. Kaplan-Meier curves were constructed to compare all-cause mortality among the three groups of patients, based on ACS type and left ventricular ejection fraction (LVEF). Multivariable Cox regression was performed to identify independent predictors of all-cause mortality.

Results

Of a total of 563 patients, 264 had mild (46.9%), 193 moderate (34.3%) and 106 severe AS (18.8%). The mean follow-up duration was 2.5 (± 2.4) years. Majority of patients (72.5%) presented with NSTEMI. Patients with moderate and severe AS had higher rates of all-cause mortality compared to those with mild AS (49.7% vs. 51.4% vs. 35.6% respectively, p=0.002). Concomitant moderate (HR 1.439, 95% CI 1.012–2.048, p=0.043) and severe AS (HR 1.844, 95% CI 1.159–2.933, p=0.010) were independent predictors of all-cause mortality after adjusting for age, gender, LVEF, ACS type, chronic kidney disease, diabetes, hypertension, coronary artery bypass grafting and aortic valve replacement as a time-dependent variable. The Kaplan-Meier curves demonstrated excess mortality in moderate and severe AS, compared to the mild AS group (p<0.001), with similar survival trends observed in the STEMI and the NSTEMI groups, as well as those with preserved LVEF.

Conclusion

Regardless of the ACS presentation type, long-term excess mortality in those with concomitant moderate or severe AS was observed. The adverse prognosis typically observed in patients with concomitant severe AS, in the setting of ACS, extends to patients with moderate AS.

Funding Acknowledgement

Type of funding sources: None.

Association of body mass index with long-term outcomes after elective and semi-urgent percutaneous coronary intervention

Background

While obesity is associated with cardiovascular mortality and morbidity, patients with higher body mass index (BMI) may have better outcomes post-percutaneous coronary intervention (PCI). This “obesity paradox” is controversial and needs clarification.

Purpose

We aimed to investigate the relationship between BMI and outcomes post-PCI in an Asian cohort.

Methods

A retrospective cohort study was performed on consecutive patients who underwent semi-urgent PCI for non-ST elevation myocardial infraction or unstable angina, and elective PCI for stable angina from January 2014 to December 2015 in a tertiary centre. Patients were underweight (BMI <18.5), normal weight (BMI 18.5–22.9), overweight (BMI 23–24.9), pre-obese (BMI 25–29.9) or obese (BMI ≥30), according to the WHO Asian classification. The primary endpoint was all-cause mortality. The secondary outcomes were subsequent events of stroke or transient ischemic attack, myocardial infarction (MI) and congestive cardiac failure (CCF).

Results

1,610 patients were followed up for 3.71 (±0.97) years, 19.7% were female and mean age was 62.1 years (Table 1). BMI showed a U-shaped relationship with the incidence of death (p<0.001), MI (p=0.005), and CCF (p<0.001) (Figure 1A), which was also shown on Kaplan Meier analysis (Figures 1B-E). With reference to normal weight patients on multivariable Cox analysis, overweight (adjusted HR 0.64, 95% CI 0.42–0.97) and pre-obese (adjusted HR 0.55, 95% CI 0.38–0.80) patients had lower mortality. Underweight patients had higher risk (adjusted HR 2.12, 95% CI 1.01–4.46), while pre-obese patients had lower risk of MI (adjusted HR 0.56, 95% CI 0.34–0.92) compared to normal weight patients. Underweight and obese patients had higher risk of CCF (underweight: adjusted HR 3.05, 95% CI 1.45–6.42; obese: adjusted HR 1.86, 95% CI 1.03–3.35) compared to normal weight patients.

Conclusion

Patients at the lower and upper extremes of BMI demonstrated higher risk of mortality, MI and CCF post-PCI.

Funding Acknowledgement

Type of funding sources: None.

The prognostic outcomes of acute myocardial infarction stratified according to metabolic health and obesity status

Background

There has been emerging evidence on the favourable cardiovascular disease incidence in non-obese subjects with healthy metabolism. However, little is known regarding the prognosis across the metabolic phenotypes once cardiovascular disease is established. This study examines the prognosis of patients with acute myocardial infarction (AMI) stratified according to metabolic health and obesity status.

Methods

A retrospective study conducted in a tertiary hospital between 2014–2021. Consecutive patients with AMI were allocated into 4 groups based on metabolic and obesity profile: metabolically healthy obesity (MHO), metabolically healthy non-obesity (MHNO), metabolically unhealthy obesity (MUO) and metabolically unhealthy non-obesity (MUNO). The primary outcome was all-cause mortality. Cox regression examined the independent association between mortality and metabolic phenotypes, adjusting for age, sex, AMI type and ejection fraction.

Results

A total of 9958 patients were studied with majority (68.5%) in the MUNO group, followed by MUO (25.1%), MHNO (5.6%), and MHO (0.8%). MHO patients had lowest mortality (7.4%), followed by MHNO (9.7%), MUO (19.2%) and MUNO (22.6%, p<0.001). Relative to MHNO, MUO (HR 1.610, 95% CI 1.198–2.163, p=0.002) and MUNO (HR 1.383, 95% CI 1.043–1.835, p=0.024) had significantly higher mortality risk, but not MHO (HR 1.514, 95% CI 0.649–3.534, p=0.337), after adjusting for confounders. Kaplan-Meier curves showed favourable survival in metabolically healthy groups with clear divergence from metabolically unhealthy groups (p<0.001). There were stepwise increments in mortality with increasing number of metabolic risk factors regardless of obesity status (p<0.001). Favourable survival was observed in overweight and obese versus normal weight patients regardless of metabolic health.

Conclusion

Metabolically healthy AMI patients had favourable prognosis compared to metabolically unhealthy patients. The obesity paradox was observed in the AMI cohort, but the beneficial effects of obesity appeared not as pronounced in magnitude as in metabolically healthy groups.

Funding Acknowledgement

Type of funding sources: None.

Tissue factor cytoplasmic domain exacerbates post-infarct left ventricular remodeling via orchestrating cardiac inflammation and angiogenesis

Introduction

The coagulation protein tissue factor (TF) regulates inflammation and angiogenesis via its cytoplasmic domain in infection, cancer and diabetes. While TF is highly abundant in the heart and implicated in cardiac injuries and dysfunction, the contribution of its cytoplasmic domain in cardiac pathology remains unclear.

Purpose

We aimed to investigate the contribution of the cytoplasmic domain of TF to post-infarct myocardial injury and adverse left ventricular (LV) remodeling.

Methods and results

Myocardial infarction was induced by permanent occlusion of the left anterior descending coronary artery. Male mice with C57BL/Jax background were used for the study. Compared with wild-type mice, mice lacking the TF cytoplasmic domain (TFΔCT) had a higher survival rate (90.5% versus 70%, p=0.0298) during a 28-day follow-up after myocardial infarction. Among surviving mice, TFΔCT mice had better cardiac function and less LV remodeling (ESV: 114.5±13.1mL for WT, 67.06±10.8mL for TFΔCT, p<0.001; EDV: 146.6±12.4mL for WT, 99.97±11.71mL for TFΔCT, p<0.001) than wild-type mice. Bone marrow chimerism indicated that deletion of the TF cytoplasmic domain in either bone marrow-derived cells or cardiac resident cells could alleviate post-infarct cardiac dysfunction. Speckle-tracking strain analysis revealed that the overall improvement of post-infarct cardiac performance in TFΔCT mice was attributed to reduced myocardial deformation in the peri-infarct region (strain-%: 11.14±0.97 for WT, 15.34±1.10 for TFΔCT, p=0.007; strain rate-/s: 3.89±0.26 for WT, 5.18±0.21 for TFΔCT, p=0.0005). Histological analysis demonstrated that TFΔCT hearts had in the infarct area greater proliferation of endothelial cells and myofibroblasts accompanied with better scar formation. Compared with wild-type hearts, infarcted TFΔCT hearts showed less infiltration of proinflammatory cells with concomitant lower expression of protease-activated receptor-1 (PAR1)-Rac1 axis. Furthermore, infarcted TFΔCT hearts presented markedly higher peri-infarct vessel density associated with enhanced endothelial cell proliferation and higher expression of PAR2 and PAR2-associated pro-angiogenic pathway factors.

Conclusions

Our findings demonstrate that the TF cytoplasmic domain exacerbates post-infarct cardiac injury and adverse LV remodeling via differential regulation of inflammation and angiogenesis. Targeted inhibition of the TF cytoplasmic domain-mediated intracellular signaling may ameliorate post-infarct LV remodeling without perturbing coagulation.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): National University Health System of Singapore

Effect of coronavirus infection on the human heart: A scoping review

BACKGROUND

The global coronavirus disease 2019 pandemic has highlighted the importance of understanding the cardiovascular implications of coronavirus infections, with more severe disease in those with cardiovascular co-morbidities, and resulting cardiac manifestations such as myocardial injury, arrhythmias, and heart failure.

DESIGN

A systematic review of the current knowledge on the effects of coronavirus infection on the cardiovascular system in humans was performed and results were summarized.

METHODS

Databases such as MEDLINE, EMBASE, CENTRAL, Scopus, Web of Science, ClinicalTrials.gov, Chinese Knowledge Resource Integrated Database and Chinese Clinical Trial Registry were searched on 20 March 2020.

RESULTS

In total, 135 studies were included, involving severe acute respiratory syndrome, Middle East respiratory syndrome, coronavirus disease 2019 and other coronaviruses. Most were case reports, case series and cohort studies of poor to fair quality. In post-mortem examinations of subjects who died from infection, around half had virus identified in heart tissues in severe acute respiratory syndrome, but none in Middle East respiratory syndrome and coronavirus disease 2019. Cardiac manifestations reported include tachycardia, bradycardia, arrhythmias, and myocardial injury, secondary to both systemic infection and treatment. Cardiac injury and arrhythmias are more prevalent in coronavirus disease 2019, and elevated cardiac markers are associated with intensive care unit admission and death. In severe acute respiratory syndrome, Middle East respiratory syndrome, and coronavirus disease 2019, comorbidities such as hypertension, diabetes mellitus, and heart disease are associated with intensive care unit admission, mechanical ventilation, and mortality. There were cases of misdiagnosis due to overlapping presentations of cardiovascular diseases and coronavirus infections, leading to hospital spread and delayed management of life-threatening conditions.

CONCLUSION

This review highlighted the ways in which coronaviruses affect cardiovascular function and interacts with pre-existing cardiovascular diseases.

P5719Plasma proteomics identify plaque-related proteins that predict long-term recurrent coronary events in patients with acute coronary syndrome

Background

Coronary plaque burden and composition drive recurrent ischaemic events in coronary artery disease.

Purpose

We first investigated the association between plasma proteins and coronary plaque characteristics in a cohort of asymptomatic individuals with low-intermediate Framingham Risk Score. Plaque-related proteins were further evaluated in a second cohort of patients with acute coronary syndrome (ACS) to determine their prognostic value for predicting future myocardial infarction (MI).

Methods

We profiled 1305 plasma proteins using an aptamer-based array (SOMAscan) in asymptomatic individuals who had undergone 384-slice coronary computed tomography angiography. Plaques were categorized by composition as calcified or non-calcified. First, we identified proteins that were different (based on multiple testing adjusted p-values: q-value <0.05) between 250 ACS patients who suffered a recurrent MI event on follow-up compared with another 250 ACS patients who remained event-free using Mann-Whitney U test. Next, protein candidates that also correlated (Pearson's p<0.05) with specific categories of plaque composition were evaluated using a cox proportional hazards model to determine the risk of recurrent MI, adjusting for potential confounders in the second cohort.

Results

A total of 65 and 120 plasma proteins were significantly associated with calcified and non-calcified plaques respectively in the asymptomatic cohort (N=79). Of these 185 proteins, 23 proteins were differentially expressed (DE) between ACS patients with and without recurrent MI events (median follow-up 1811 days). The top three up-and down-regulated proteins in the recurrent MI group were macrophage-capping protein, trefoil factor 3 and cystatin-SN (median FC 1.22, 1.17 and 1.17; q-value 4.34x10–6, 2.18x10–4, 3.17x10–3 respectively) and fibroblast growth factor 20, lymphotoxin a2/b1 and vascular endothelial growth factor receptor 2 (median FC 0.92, 0.94 and −0.090; q-value 1.31x10–3, 9.45x10–3 and 3.90x10–3) respectively. The quartiles of these protein concentrations were also associated with risk of recurrent MI, (log-rank test p-value range from 2.71x10–7 to 0.04). Of the DE proteins, the adjusted hazards ratio (HR) of cystatin-SN in the highest quartile (Q4) was 1.44 times that of the first quartile (Q1) (adjusted HR: 1.44, 95% CI: 0.93–2.2) and higher plasma concentration of cystatin-SN was associated with increasing risk of recurrent MI events (Trend test p=0.004). On the other hand, the highest quartile of fibroblast growth factor 20 was associated with 44% reduction in risks of recurrent MI adjusted HR: 0.56, 95% CI of HR: 0.35–0.87), with significant trend test (p=0.0096).

Conclusions

Large-scale plasma proteomics identified novel plaque-related proteins predictive of recurrent coronary events in patients with ACS. Further studies may help unravel the biological underpinnings of these circulating proteins and their potential as novel prognostic biomarkers.

Acknowledgement/Funding

This work was supported by grant NMRC/CSA-INV/0001/2016 from the National Medical Research Council, Singapore.

P2582Signature of plasma extracellular vesicles associated proteins in acute myocardial infarction patients

Background

Prediction of left ventricular (LV) remodeling post-acute myocardial infarction (AMI) remains challenging. Several circulating biomarkers have been associated with post-AMI LV remodeling, however, there is no biomarker available to distinguish adverse versus reverse LV remodeling.

Purpose

In this study, we aimed to assess the association of extracellular vesicles (EVs) associated proteins with LV remodeling post-AMI.

Methods

Plasma EVs were isolated via precipitation with dextran sulphate as we previously reported. The protein levels of EV associated von Willebrand factor (VWF), SerpinC1 (antithrombin-III), plasminogen and SerpinF2 (alpha 2-antiplasmin) were determined in the citrate-anticoagulated plasma from 57 healthy subjects and 200 patients recruited in the Post-AMI Left Ventricular Remodeling Biomarker Analysis (PAMILA) study. Patients were categorized into two groups: adverse LV remodeling (n=100) characterized by an increase or reverse LV remodeling (n=100) characterized by a decrease, in LV end systolic volume by ≥15% over 6 months. Patients' plasma was collected at baseline (within 3 days after percutaneous coronary intervention), 1 month and 6 months post-AMI. Log transformation of EV protein levels was performed for assessment in a multiple multi-level longitudinal data analysis with structural equation model (with level of significance fixed at 0.05).

Results

Compared to healthy subjects, baseline protein levels of EV associated VWF and SerpinF2 were significantly higher in post-AMI patients, whereas no difference was observed in SerpinC1 and plasminogen. Among the patients, those on statins (196 out of 200 patients) showed lower protein levels of EV associated VWF (p<0.001) and plasminogen (p=0.003), whereas patients treated with P2Y12 platelet inhibitors (195 out of 200 patients) showed higher protein levels of EV associated VWF (p=0.003) and plasminogen (p=0.035). Multiple multi-level longitudinal data analysis with structural equation model showed that protein levels of EV associated VWF (p<0.001) and SerpinC1 (p=0.021) were lower in patients with adverse LV remodeling than that in patients with reverse LV remodeling during the 6-month follow-up post-AMI. In contrast, protein levels of EV associated plasminogen (p=0.002) and SerpinF2 (p=0.002) were higher in patients with adverse LV remodeling. The differences in the four EV associated proteins between patients with adverse versus reverse LV remodeling remain significant after adjusting for age, gender, ethnicity, medications, lipid profile and risk factors (diabetes, hypertension, dyslipidemia and smoking).

Conclusions

Lower levels of EV associated coagulation proteins (VWF and SerpinC1) and higher levels of EV associated fibrinolytic proteins (plasminogen and SerpinF2) were presented in patients with adverse LV remodeling compared to those with reverse LV remodeling post-AMI.

Acknowledgement/Funding

National University Health System Singapore (NUHS O-CRG 2016 Oct-23) to JW Wang

Can Bedside Ultrasonography of Internal Jugular Vein Replace Ultrasonography of Inferior Vena Cava for Volume Status Estimation?

Introduction

Estimation of haemodynamic status of acute and critically ill patients at Accident & Emergency (A&E) Departments is important. Measurement of inferior vena cava (IVC) diameter and collapsibility index by bedside ultrasound (USG) was known to correlate well with volume status of these patients. However, the value of similar estimation based on USG measurement of internal jugular vein (IJV) diameter was seldom studied. Whether USG measurement of IJV diameter can replace that of IVC diameter was unknown.

Methods

This was a cross-sectional study using a convenience sample of healthy volunteers among staff of a local A&E. The diameter of IJV and IVC (IJVD and IVCD) of the 51 participants were measured by bedside USG. The corresponding collapsibility index (CI) of IJV and IVC were then calculated. The correlation between IJVD and IVCD was assessed by the use of Bland-Altman plot.

Results

Median value of IVC-CI and of IJV-CI was 29.41% and 17.12% respectively. The mean of the difference of measurement of IJV-CI and IVC-CI was −11.10% (95% Confidence Interval: −15.27 to −6.92). The limits of agreement of the above difference were −40.77% and 18.58%. The range of these limits was too wide.

Conclusion

Because the range of limits of agreement between IJV-CI and IVC-CI were too wide, IJV-CI may not be used as an alternative to IVC-CI for the estimation of the volume status of normal adults.

Health claims on food products in Southeast Asia: regulatory frameworks, barriers, and opportunities

The Association of Southeast Asian Nations aims to act as a single market and allow free movement of goods, services, and manpower. The purpose of this article is to present an overview of the current regulatory framework for health claims in Southeast Asia and to highlight the current barriers and opportunities in the regulatory frameworks in the Association of Southeast Asian Nations. To date, 5 countries in Southeast Asia, i.e., Indonesia, Malaysia, the Philippines, Singapore, and Thailand, have regulations and guidelines to permit the use of health claims on food products. There are inconsistencies in the regulations and the types of evidence required for health claim applications in these countries. A clear understanding of the regulatory frameworks in these countries may help to increase trade in this fast-growing region and to provide direction for the food industry and the regulatory community to develop and market food products with better nutritional quality tailored to the needs of Southeast Asian consumers.

Acute carbon monoxide poisoning in a regional hospital in Hong Kong: historical cohort study

OBJECTIVES

This study aimed to describe the clinical profiles of all patients with carbon monoxide poisoning admitted to a regional hospital in order to enhance the vigilance of health care professionals for delayed neurological sequelae associated with carbon monoxide poisoning and to identify the prognostic factors associated with their development. This study also aimed to assess the impact of hyperbaric oxygen therapy on the development of delayed neurological sequelae in these patients.

METHODS

This was a historical cohort study in which all patients with a diagnosis of carbon monoxide poisoning managed in a regional hospital in Hong Kong from 12 February 2003 to 8 November 2013 were recruited. Main outcome measures included delayed neurological sequelae.

RESULTS

Of the clinical profiles of 93 patients analysed, 24 patients received hyperbaric oxygen therapy and did not develop delayed neurological sequelae. Seven patients who did not receive hyperbaric oxygen therapy developed delayed neurological sequelae. Comparison of groups with and without delayed neurological sequelae (excluding hyperbaric oxygen therapy-treated patients) revealed that loss of consciousness (P=0.038), Glasgow Coma Scale score of 3 (P=0.012), elevated troponin level (P<0.001), higher creatine kinase level (P=0.008), and intubation requirement (P=0.007) were possible prognostic factors for the development of delayed neurological sequelae.

CONCLUSION

Although not statistically significant, this study showed a 100% protective effect of hyperbaric oxygen therapy against development of severe delayed neurological sequelae in patients with severe carbon monoxide poisoning. Further study with better study design is warranted. Loss of consciousness, low Glasgow Coma Scale score, intubation requirement, elevated troponin and higher creatine kinase levels were possible prognostic factors for development of delayed neurological sequelae in patients with severe carbon monoxide poisoning. A well-defined treatment protocol, appropriate follow-up duration and neuropsychiatric tests together with a hospital-based hyperbaric chamber are recommended for management of patients with severe carbon monoxide poisoning.

Fasxiator, a novel factor XIa inhibitor from snake venom, and its site-specific mutagenesis to improve potency and selectivity

BACKGROUND

Bleeding remains a major limitation of standard anticoagulant drugs that target the extrinsic and common coagulation pathways. Recently, intrinsic coagulation factors are increasingly being investigated as alternative targets for developing anticoagulant drugs with lower bleeding risk.

OBJECTIVES

Goals were to (i) identify novel anticoagulants selectively targeting intrinsic coagulation pathway and (ii) characterize and further improve the properties of the identified anticoagulants.

METHODS AND RESULTS

We have isolated and sequenced a specific factor XIa (FXIa) inhibitor, henceforth named Fasxiator, from the venom of the banded krait snake, Bungarus fasciatus. It is a Kunitz-type protease inhibitor that prolonged activated partial thromboplastin time without significant effects on prothrombin time. Fasxiator was recombinantly expressed (rFasxiator), purified, and characterized to be a slow-type inhibitor of FXIa that exerts its anticoagulant activities (doubled activated partial thromboplastin time at ~ 3 μmol L(-1) ) by selectively inhibiting human FXIa in in vitro assays. A series of mutants were subsequently generated to improve the potency and selectivity of recombinant rFasxiator. rFasxiatorN17R,L19E showed the best balance between potency (IC50 ~ 1 nmol L(-1) ) and selectivity (> 100 times). rFasxiatorN17R,L19E is a competitive slow-type inhibitor of FXIa (Ki  = 0.86 nmol L(-1) ), possesses anticoagulant activity that is ~ 10 times stronger in human plasma than in murine plasma, and prolonged the occlusion time of mice carotid artery in FeCl3 -induced thrombosis models.

CONCLUSION

We have isolated an exogenous FXIa specific inhibitor, engineered it to improve its potency by ~ 1000 times and demonstrated its in vitro and in vivo efficacy. These proof-of-principle data supported the further development of Fasxiator as a novel anticoagulant candidate.

Quantitative ultrasound and fracture risk prediction in non-osteoporotic men and women as defined by WHO criteria

This study sought to determine the association between calcaneal quantitative ultrasound (QUS) and fracture risk in individuals without osteoporosis according to the World Health Organization criteria (i.e., BMD T-score > -2.5). We found that calcaneal QUS is an independent predictor of fracture risk in women with non-osteoporotic bone mineral density (BMD).

INTRODUCTION

More than 50 % of women and 70 % of men who sustain a fragility fracture have BMD above the osteoporotic threshold (T-score > -2.5). Calcaneal QUS is associated with fracture risk. This study aimed to test the hypothesis that low calcaneal QUS is associated with increased fracture risk in individuals with non-osteoporotic BMD.

METHODS

We included 312 women and 390 men aged 62-90 years with BMD T-score > -2.5 at femoral neck. QUS was measured in broadband ultrasound attenuation (BUA) at the calcaneus using a CUBA sonometer. BMD was measured at the femoral neck (FNBMD) by dual energy X-ray absorptiometry using GE Lunar DPX-L densitometer. The incidences of any fragility fracture were ascertained by X-ray reports during the follow-up period from 1994 to 2011.

RESULTS

Of the 702 participants, 26 % of women (n = 80/312) and 14 % of men (n = 53/390) experienced at least one fragility fracture during the follow-up period. In women, after adjusting for covariates, increased risk of any fracture was significantly associated with decreased BUA (HR = 1.50; 95 % CI, 1.13-1.99). Compared with that of FNBMD, the models with BUA, in women, had greater AUC (0.71, 0.85, 0.71 for any, hip and vertebral fracture, respectively), and yielded a net reclassification improvement of 16.4 % (P = 0.009) when combined with FNBMD. In men, BUA was not significantly associated with fracture risk before and after adjustment.

CONCLUSION

These results suggest that calcaneal BUA is an independent predictor of fracture risk in women with non-osteoporotic BMD.

Random blinded rechecking of sputum acid-fast bacilli smear using fluorescence microscopy: 8 years' experience

BACKGROUND

The Hong Kong TB Reference Laboratory is a high volume laboratory examining around 400 sputum acid-fast bacilli smears daily using fluorescence microscopy (FM).

OBJECTIVE

To assess the effectiveness of blinded rechecking applied to FM in a high-throughput laboratory.

METHOD

From 2003, 2.5% (5% in 2003 and 2004) of all smears were randomly selected, relabelled and assigned to each technician (rechecker) in turn. These smears were restained and re-examined. Discordance between initial screener and rechecker was resolved by a controller.

RESULTS

From 2003 to 2010, low false-negative (LFN) errors (0.10-0.27%) were within the critical values, at 85% (1 year) and 90% (7 years) sensitivity. However, LFN error (0.28-0.62%) among recheckers was prominent. There were also low false-positive (LFP) cases (0.13-0.75%), but subsequent cultures showed these to be mycobacteria culture-positive. This relatively poor performance among the recheckers might be due to background fluorescence increase after restaining and/or inefficiency of the rechecking procedure.

CONCLUSION

In a high-throughput laboratory, blind rechecking is a good means of quality assurance. To minimise false LFP, problems due to restaining should be resolved before blinded rechecking can be generally applied in the field for FM where mycobacterial cultures are not routinely performed.

Do children die? A retrospective review of deaths in a children's hospital

INTRODUCTION

We present a profile of deaths over two years in the medical departments of a children's hospital. The findings would help us better understand the individual dying experience of these patients. Service gaps and ways to optimise provision of supportive care were identified in the process.

METHODS

The inpatient notes of all children who died in the medical wards, including intensive care unit, were traced and reviewed by the investigators. Demographic data, diagnoses, length of stay and the care received were recorded.

RESULTS

A total of 68 children died in the two years. They were representative of all deaths nationally in terms of diagnoses. Two-thirds of the children died in the intensive care unit after having stayed there for an average of five days. All but one patient had invasive ventilation till they died. Eight out of every ten cases were assessed to be actively dying while being cared for. Most had 'Do-Not-Resuscitate' status in place, but few had been offered the option to choose the place of care or death when it became clear that they would not survive.

CONCLUSION

More efforts could be made to improve the care of dying children and their families. The Paediatric Palliative Service could assist in advance care planning at the end of life.

Acute myocardial infarction in young Asian women: a comparative study on Chinese, Malay and Indian ethnic groups

INTRODUCTION

There is a paucity of data on acute myocardial infarction (AMI) in young Asian women and of comparative data among various ethnic groups with respect to risk factor profile and clinical outcomes. We present a comprehensive overview of the clinical characteristics of young Asian women with AMI and a comparative analysis among Chinese, Malay and Indian women in a multi-ethnic Asian country.

METHODS

We studied 45 Asian female patients aged 50 years and below who were admitted to our hospital with a diagnosis of ST-segment elevation myocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI).

RESULTS

Overall, diabetes mellitus, hypertension and hyperlipidaemia were prevalent in the study population. Hyperlipidaemia was more prevalent among Indian patients, while diabetes mellitus was more common among Malay patients. Only a minority of the study patients were current smokers. Among the 20 patients admitted with STEMI, 17 (85 percent) received urgent reperfusion therapy. The mean symptom-to-balloon time and door-to-balloon time for the Malay patients were longer compared to those for other ethnic groups. Among the 25 patients admitted with NSTEMI, 12 (48 percent) underwent coronary revascularisation therapy. The average duration of hospital stay was 4 +/- 4.1 days, with no significant difference observed among the various ethnic groups.

CONCLUSION

Many young Asian women with AMI have identifiable risk factors that are different from those found in the Western population. There seems to be an ethnic effect on the prevalence of these risk factors and door-to-balloon time.

Dose selection for a direct and selective factor IXa inhibitor and its complementary reversal agent: translating pharmacokinetic and pharmacodynamic properties of the REG1 system to clinical trial design

We performed detailed pharmacokinetic and pharmacodynamic modeling of REG1, an anticoagulation system composed of the direct factor IXa (FIXa) inhibitor pegnivacogin (RB006) and its matched active control agent anivamersen (RB007), with a focus on level of target inhibition to translate phase 1 results to phase 2 dose selection. We modeled early-phase clinical data relating weight-adjusted pegnivacogin dose and plasma concentration to prolongation of the activated partial thromboplastin time (aPTT). Using an in vitro calibration curve, percent FIXa inhibition was determined and related to aPTT prolongation and pegnivacogin dose and concentration. Similar methods were applied to relate anivamersen dose and level of reversal of pegnivacogin anticoagulation. Combined early-phase data suggested that ≥0.75 mg/kg pegnivacogin was associated with >99% inhibition of FIX activity and prolongation of plasma aPTT values ≈2.5 times above baseline, leading to selection of a 1 mg/kg dose for a phase 2a elective percutaneous coronary intervention study to achieve a high intensity of anticoagulation and minimize intersubject variability. Phase 2 validated our predictions, demonstrating 1 mg/kg pegnivacogin yielded plasma concentrations ≈25 μg/ml and >99% inhibition of FIX activity. The relationship between the anivamersen to pegnivacogin dose ratio and degree of pegnivacogin reversal was also validated. Our approach decreased the need for extensive dose-response studies, reducing the duration, complexity and cost of clinical development. The 1 mg/kg pegnivacogin dose and a range of anivamersen dose ratios are being tested in the phase 2b RADAR study (NCT00932100).

Malignant peripheral nerve sheath tumor mimicking carotid body tumor--case report and review

Malignant peripheral nerve sheath tumor is a rare neurogenic tumor that usually presents in geriatic patients. Typically, it is found in the trunk and extremities and rarely presents in the head and neck region. It may mimic a carotid body tumor when it presents in the neck. We report the first case of malignant peripheral nerve sheath tumor of the vagus nerve in an adolescent boy. He presented with an asymptomatic lateral neck lump that was thought to be a benign schwannoma on preoperative imaging. We describe the diagnostic dilemma and management difficulties in this patient and review the literature.

Usefulness of resistant gene markers for predicting treatment outcome on second-line anti-tuberculosis drugs

AIM

Mutations in rrs [nucleotide (nt) 1401], gyrA gene (codons 90, 91 or 94), tlyA, ethA and thyA genes of Mycobacterium tuberculosis (MTB) were evaluated for their usefulness in predicting treatment outcome of kanamycin (KM), capreomycin (CPM), ofloxacin (OFX), ethionamide (ETH) and para-aminosalicylic acid (PAS).

METHODS AND RESULTS

DNA sequence analyses of these genes were performed against 188 MTB isolates obtained from patients put on second-line anti-TB drugs (SLDs) with well-documented clinical history and treatment outcome. Mutations in rrs and gyrA have 100% positive predictive value (PPV) in predicting treatment failure for KM and OFX, while 88·9 and 80% were obtained, respectively, when tlyA and rrs mutations were considered in CPM. For ETH and PAS, the PPV of using ethA and thyA mutations to predict treatment failure was 82·5 and 89·3%, respectively.

CONCLUSIONS

Our study demonstrated high specificities of gene mutations in predicting poor treatment outcome; however, further technical advancement is required to make the molecular detection of resistances to other SLDs feasible in clinical laboratories.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to correlate different polymorphisms of major SLD resistance gene markers with predicted treatment outcome, using an international set of well-documented clinical MTB strains.

Utilisation of emergency medical service among Singapore patients presenting with ST-segment elevation myocardial infarction: prevalence and impact on ischaemic time

BACKGROUND

Previous studies in Western countries found that the emergency medical service (EMS) was under-used in patients with myocardial infarction.

AIM

We sought to determine the prevalence of immediate EMS utilisation among Singapore patients presenting with ST-segment elevation myocardial infarction (STEMI), and correlated the use of the EMS with the symptom-to-balloon and door-to-balloon times.

METHODS

We studied 252 patients admitted with STEMI to our institution from August 2008 to September 2009. Information regarding demographic characteristics, whether EMS was used, reperfusion procedural details and mortality rates were collected prospectively.

RESULTS

Among the recruited patients, 89 (35.3%) used the EMS (EMS group) and 163 (64.7%) did not use the EMS (non-EMS group). In the latter group, 98 (60.1%) arrived at our institution through their own transport, 56 (34.4%) first consulted general practitioners, and 9 (5.5%) initially consulted another hospital without acute medical services. Among the 245 (out of 252, 97.2%) patients who received percutaneous coronary intervention (PCI), the EMS group was more likely to undergo primary PCI (P= 0.003) while the non-EMS group was more likely to undergo non-urgent PCI (P= 0.002). In patients who underwent primary PCI, the EMS group had a shorter symptom-to-balloon time (average difference 81.6 min, P= 0.002). The door-to-balloon time was similar for both groups.

CONCLUSION

Despite the availability of a centralised EMS, 64.7% of patients with STEMI did not contact EMS at presentation. These patients were less likely to receive primary PCI and had a significantly longer symptom-to-balloon time.

Comparing histopathological classification with MYCN, 1p36 and 17q status detected by fluorescence in situ hybridisation from 14 untreated primary neuroblastomas in Singapore

INTRODUCTION

Neuroblastoma is the most common extracranial solid tumour in children, accounting for about 5.3 percent of all childhood cancers in Singapore. Several genetic abnormalities have been reported as prognostic markers, including amplification of the MYCN gene, deletion of the short arm of chromosome 1 (1p) and gain of the long arm of chromosome 17 (17q). However, the correlation between tumour histology and these genetic parameters remains to be established in our local population.

METHODS

14 untreated primary neuroblastoma tumours, diagnosed consecutively in our hospital between 2003 and 2007, were included for this study. Tumour tissues were classified histologically as favourable or unfavourable, according to the modification of World Heath Organization Classification of Tumours, by associating the degree of differentiation and mitotic-karyorrhectic index of the neuroblastoma to the age of the patient. Fluorescence in situ hybridisation analysis for MYCN, 1p status and 17q status were subsequently performed on tumour touch imprints.

RESULTS

Five tumours with favourable histology were all negative for the three genetic parameters being investigated. The other nine tumours showing unfavourable histology exhibited one or more of the three genetic parameters. All MYCN amplified tumours either had additional 1p deletion and/or 17q gain.

CONCLUSION

Our limited data suggests that 1p deletion and 17q gain are reliable independent parameters correlating with an unfavourable histology and poor clinical outcome. The use of 1p deletion and 17q gain studies, in addition to MYCN amplification studies, should be considered routinely in predicting prognosis in neuroblastomas.

Prevalence and predictors of premature discontinuation of dual antiplatelet therapy after drug-eluting stent implantation: importance of social factors in Asian patients

AIM

Premature discontinuation of antiplatelet therapy is an independent predictor of late stent thrombosis. We sought to determine the prevalence and predictors of premature discontinuation of antiplatelet therapy after drug-eluting stent implantation among patients in Asia.

METHODS

A total of 207 consecutive patients who underwent drug-eluting stent implantation at our institution was followed up after 1 year. Premature discontinuation of antiplatelet therapy was defined as omission of aspirin and/or clopidogrel for 1 week or more.

RESULTS

Four (1.9%) patients died and the remaining 203 patients formed the study population. Prevalence of premature discontinuation of antiplatelet therapy was 12.8% (n= 26, aspirin, n= 12; clopidogrel, n= 9; both, n= 5). The median duration between stent implantation and discontinuation of antiplatelet therapy was 2.8 months. Reasons for discontinuation included cost (n= 1), gastric discomfort (n= 1), allergy (n= 3), bleeding (n= 3), advice from doctors (n= 7) and no reason (n= 11). Logistic regression showed that living alone was the only independent predictor of premature discontinuation of dual antiplatelet therapy (50.0% vs 11.3%, P= 0.001).

CONCLUSION

Among Asian patients who have undergone drug-eluting stent implantation, 12.8% discontinued dual antiplatelet therapy within 12 months. Living alone is associated with a fivefold increase in risk of premature drug discontinuation.

A randomized, repeat-dose, pharmacodynamic and safety study of an antidote-controlled factor IXa inhibitor

BACKGROUND

Active and safe reversibility of anticoagulation is an unmet need in clinical care. Factor IXa, required for rapid thrombin generation on platelet surfaces, is a novel target for modulating coagulation. REG1 comprises RB006 (drug) and RB007 (antidote). RB006, a ribonucleic acid aptamer, exerts its anticoagulant effect by selectively binding FIXa. RB007, the complementary oligonucleotide antidote, binds to RB006 by Watson-Crick base pairing, neutralizing its anti-FIXa activity.

OBJECTIVE

To test the multiple repeat-dose safety, intraindividual pharmacodynamic reproducibility and graded active reversibility of REG1.

METHODS

We randomized 39 healthy volunteers to receive either three consecutive weight-adjusted, drug-antidote treatment cycles, or double placebo. Each treatment cycle included an intravenous bolus of 0.75 mg kg(-1) RB006, followed 60 min later by a descending dose of RB007, ranging from a 2 : 1 to 0.125 : 1 antidote/drug ratio (1.5 mg kg(-1) to 0.094 mg kg(-1) RB007). Serial clinical assessments and coagulation measurements were performed through 14 days postrandomization.

RESULTS

Repeat doses of RB006 achieved highly reproducible activated partial thromboplastin time (APTT) levels with low intrasubject variability (coefficient of variation 5.5%, intraclass correlation coefficient 5.8 at 15 min postdose), while repeat doses of RB007 reversed the APTT levels dose-dependently and reproducibly. There was no major bleeding and there were no other serious adverse events.

CONCLUSIONS

This is the first human study demonstrating multiple repeat-dose safety, intraindividual pharmacodynamic reproducibility and graded active reversibility of an RNA aptamer-oligonucleotide antidote pair. The results lay the foundation for studying the translation of this novel anticoagulation platform to a wide variety of clinical applications.

Ex-utero intrapartum treatment: a controlled approach to the management of anticipated airway problems in the newborn

Airway problems in an unborn foetus that may cause obstruction can be safely managed using an ex-utero intrapartum technique. Advanced technology now allows many congenital airway problems to be diagnosed in the prenatal period. Careful prenatal planning of an ex-utero intrapartum treatment allows safe airway control while the foetus remains on uteroplacental support. It avoids the need for emergent intervention of an acutely obstructed airway in a neonate that often has disastrous consequences.

Antecedent risk factors and their control in young patients with a first myocardial infarction

INTRODUCTION

Identifying and controlling cardiovascular risk factors at an early age may prevent cases of young myocardial infarction (MI). We studied age-related differences in the cumulative incidence of risk factors and the adequacy of primary prevention by surveying 1,556 patients with a first MI admitted to a tertiary hospital in Singapore.

METHODS

This is a single centre registry-based study on patients admitted with a first MI to a tertiary hospital in Singapore. We stratified the cohort into younger (45 years of age and younger) and older (older than 45 years of age) groups. The presence of five risk factors, namely: hypertension, diabetes mellitus (DM), smoking, a family history of premature MI, and hyperlipidaemia, was assessed at the point of care by interview and prior medical records when obtainable. We also determined by the same methods, if these patients were receiving active treatment for DM, hypertension or hyperlipidaemia prior to their first MI. Lipid levels were measured within 24 hours of admission.

RESULTS

96 percent of patients 45 years and younger and 92 percent of those older than 45 years had at least one antecedent risk factor. The 45 years and younger age group had a higher incidence of untreated hypertension (odds ratio 2.99, 95 percent confidence interval 2.00-4.46, p-value is less than 0.001) and hyperlipidaemia (odds ratio 1.71, 95 percent confidence interval 1.20 - 2.43, p-value is equal to 0.002).

CONCLUSION

A majority of young patients with a first MI have at least one identifiable antecedent risk factor. There is significant undertreatment of hypertension and hyperlipidaemia in this age group.

Predictors of axillary lymph node metastases in women with early breast cancer in Singapore

INTRODUCTION

The presence of axillary lymph node metastases is an important prognostic factor in breast cancer. Sentinel lymph node biopsy (SLNB) is an emerging method for the staging of the axilla. It is hoped that with SLNB, the morbidity from axillary lymph node dissection (ALND) can be avoided without compromising the staging and management of early breast cancer. However, only patients found to be SLNB negative benefit from this procedure, as those with positive SLNB may still require ALND. Our objective is to study the various clinico-pathological factors to find predictive factors for axillary lymph node involvement in early breast cancer. It is hoped that with these factors, we will be better able to identify groups of patients most likely to benefit from SLNB.

METHODS

A retrospective study of 380 early breast cancer cases (stage T1 and T2, N0, N1, M0) in women treated in the Department of General Surgery, Tan Tock Seng Hospital, between January 1999 and August 2002, was conducted. Incidence of nodal metastases was correlated with clinico-pathological factors, and analysed by univariate and multivariate analyses.

RESULTS

Approximately 35 percent of the 380 cases of early breast cancer had nodal metastases. Multivariate analyses revealed four independent predictors of node positivity: tumour size (p-value equals 0.0001), presence of lymphovascular invasion (p-value is less than 0.0001), tumours with histology other than invasive ductal or lobular carcinoma (p-value equals 0.04), and presence of progesterone receptors (p-value equals 0.05).

CONCLUSION

We have found independent preoperative predictive factors in our local population for the presence of nodal metastases. This information can aid patient selection for SLNB and improve patient counselling.

Randomised controlled trial of qigong in the treatment of mild essential hypertension

Exercise and relaxation decrease blood pressure. Qigong is a traditional Chinese exercise consisting of breathing and gentle movements. We conducted a randomised controlled trial to study the effect of Guolin qigong on blood pressure. In all, 88 patients with mild essential hypertension were recruited from the community and randomised to Goulin qigong or conventional exercise for 16 weeks. The main outcome measurements were blood pressure, health status (SF-36 scores), Beck Anxiety and Depression Inventory scores. In the qigong group, blood pressure decreased significantly from 146.3+/-7.8/93.0+/-4.1 mmHg at baseline to 135.5+/-10.0/87.1+/-7.7 mmHg at week 16. In the exercise group, blood pressure also decreased significantly from 140.9+/-10.9/93.1+/-3.5 mmHg to 129.7+/-11.1/86.0+/-7.0 mmHg. Heart rate, weight, BMI, waist circumference, total cholesterol, renin and 24 h urinary albumin excretion significantly decreased in both groups after 16 weeks. General health, bodily pain, social functioning and depression also improved in both groups. No significant differences between qigong and conventional exercise were found. In conclusion, Guolin qigong and conventional exercise have similar effects on blood pressure in patients with mild hypertension. While no additional benefits were identified, it is nevertheless an alternative to conventional exercise in the nondrug treatment of hypertension.

Disease impact and patient insight--a study on a local population of asthmatics

The cornerstone of asthma management is achieving adequate symptom control and patient education. We studied in our local population of asthmatic patients how well their symptoms were controlled with currently prescribed treatment and their insight into the disease and its management. Over a 6-month period, 93 asthmatics recruited from two local government health clinics and a state hospital were interviewed using a standard questionnaire. Patients were classified into 4 groups based on the treatment they were on according to Global Initiative for Asthma (GINA) treatment guidelines. The number of patients in Step 1 (rescue medication alone), Step 2 (1 controller medication), Step 3 (2 controller medications) and Step 4 (at least 3 controller medications) were 8, 39, 34 and 12, respectively. Except for day symptoms in Step 1 group, fewer than 50% achieved minimum day or night symptoms and no restriction of daily activities. Questions on patient insight were only available for 50 patients. Weather change (74%), air pollution (66%) and physical stress (46%) were the three highest ranked common asthma triggers. More than half correctly recognized the important symptoms of a serious asthma attack but fewer than 15% were familiar with the peak flow meter and its use or with the asthma self-management plan. Most patients perceived that their treatment had helped reduce disease severity and exacerbations. We conclude that symptom control and some aspect of patient education are still lacking in our local asthmatics.

Efficient constrained multiple sequence alignment with performance guarantee

The Constrained Multiple Sequence Alignment problem is to align a set of sequences subject to a given constrained sequence, which arises from some knowledge of the structure of the sequences. This paper presents new algorithms for this problem, which are more efficient in terms of time and space (memory) than the previous algorithms [14], and with a worst-case guarantee on the quality of the alignment. Saving the space requirement by a quadratic factor is particularly significant as the previous O(n(4))-space algorithm has limited application due to its huge memory requirement. Experiments on real data sets confirm that our new algorithms show improvements in both alignment quality and resource requirements.

Paediatric extracranial germ cell tumours: a retrospective review

INTRODUCTION

Germ cell tumours (GCTs) are rare, constituting 3% of all childhood malignancies. The aim of this study was to analyse the epidemiology and outcome of these patients.

MATERIALS AND METHODS

A retrospective, cohort study was conducted on 38 paediatric patients presenting with extracranial GCTs, treated at the Singapore General Hospital, Tan Tock Seng Hospital and Kandang Kerbau Women's and Children's Hospital from 1 January 1989 to 30 June 1999. The median age at diagnosis was 1.7 years (0 to 13 years).

RESULTS

There was no sex or racial preponderance. Eighteen patients (47.3%) had teratomas, 16 (42.1%) had yolk sac tumours, 1 (2.6%) had dysgerminoma and 3 (7.9%) had mixed GCTs. Thirty-four patients (89.5%) had Stage I disease, 1 (2.6%) had Stage II disease, 1 (2.6%) had Stage III disease and 2 (5.3%) had metastatic disease. Complete tumour resection was achieved in 36 of the 38 patients (95%). Cisplatin-based combination chemotherapy was given to 11 patients (28.9%). None of the patients received radiotherapy. Complications from chemotherapy included anaemia requiring packed red cell transfusion (n = 3), Port-a-cath sepsis requiring removal (n = 1), febrile neutropenia (n = 1) and nephropathy (n = 1).

CONCLUSION

Using the Kaplan-Meier life tables, the overall and event-free survivals at 10 years for the patients with malignant GCTs were 96% and 88%, respectively, with a mean follow-up period of 5.1 years (0.7 to 10 years). The majority of the patients presented with early Stage I disease and this contributed to our high survival rate.

Incidence of oral tissue trauma after the administration of general anesthesia

BACKGROUND

Administration of general anesthesia necessitates certain amounts of manipulation or instrumentation within the mouth that may cause some oral tissue injuries. The purpose of this study was to determine the incidence of oral tissue trauma after receiving general anesthesia. Some possible risk factors were explored.

METHODS

Four hundred and four adult patients receiving surgical procedures under general anesthesia facilitated by endotracheal intubation were included in this prospective survey. In each patient detailed oral and dental conditions were evaluated and recorded by an oral surgeon before and after operation. The extent of oral tissue trauma were computed and the type and character of the injury were recorded.

RESULTS

Twenty-eight patients (6.9%) were found to sustain various degrees of oral trauma that included soft tissue laceration, tooth fracture, prosthesis damage, tooth avulsion, ecchymosis and numbness of tongue. Preexistence of missing tooth, crown, and residual root were some possible risk factors that might predispose to complication.

CONCLUSIONS

Oral tissue trauma as it seems to be a common anesthetic complication that should be considered as a recognized hazard of general anesthesia. Understanding and recognizing oral anatomical condition and pathological change before anesthesia may help the anesthesiologists in preventing oral and dental complications and thus to avoid legal suits.

The Alvarado score and acute appendicitis

INTRODUCTION

This is a retrospective study to assess the accuracy of the Alvarado score in predicting appendicitis for patients with right iliac fossa pain.

MATERIALS AND METHODS

This is a retrospective study of consecutive patients with suspected appendicitis. The Alvarado score was computed from the admission notes and correlated with the final outcome of the patient. Patients discharged without surgery were reviewed in the outpatient's clinic to ascertain that they did not need surgery.

RESULTS

There were 148 patients in the study and 63 had appendectomies with intention to treat appendicitis. The normal appendicectomy rate was 21%. The number of patients with score 1-4, 5-6, 7-8 and 9-10 were 46, 40, 44 and 18, respectively, while the number of appendicitis in each group were 0, 2 (5%), 30 (68%) and 18 (100%), respectively. The positive and negative predictive values of Alvarado's scores of 7 or more were 77% and 97.6%, respectively.

CONCLUSION

Alvarado score is a useful tool in the diagnosis of appendicitis, especially at both ends of the scale.

Seventy percent of the Mycobacterium tuberculosis isolates in Hong Kong represent the Beijing genotype

We used spoligotyping to study 500 randomly selected pretreatment Mycobacterium tuberculosis (MTB) strains isolated in Hong Kong during the 2 year period 1998-9. It was found that amongst all MTB strains studied, the 'Beijing' genotype strains were highly prevalent in our geographic area, representing about 70% of the isolates. Unlike previous observations in Vietnam, no significant associations were found either between 'Beijing' genotype strains and all other anti-tuberculosis drug resistance phenotypes, or with particular patients' age groups, except for a weak association with isoniazid susceptibility. Eighteen of these strains exhibited spoligotype patterns that were similar but not identical to the 'Beijing' specific pattern. This is the first geographical area where genetic diversity among 'Beijing' genotype of MTB strains has been observed on this scale.

Mucinous cystadenoma of the appendix--an unusual cause of intestinal obstruction

INTRODUCTION

Report of a rare presentation of mucinous cystadenoma of the vermiform appendix.

CLINICAL PICTURE

A lady who presented with intestinal obstruction and peritonitis was found to have gangrenous small bowel caused by strangulation by a tumour of the appendix.

TREATMENT

Right hemicolectomy.

OUTCOME

The histology of the appendicular tumour was mucinous cystadenoma. The patient recovered well.

CONCLUSION

Mucinous cystadenoma of the appendix can present in many ways and it is important to recognise the pathology at operation.