Association between the extension of smoke-free legislation and incident acute myocardial infarctions in Singapore from 2010 to 2019: an interrupted time-series analysis

BACKGROUND

We examined the association between smoke-free laws implemented in the outdoors and the common areas of residential apartment blocks and reported acute myocardial infarctions (AMI) in Singapore.

METHODS

We used an interrupted time-series design and seasonal autoregressive integrated moving average models to examine the effect of the smoke-free law extensions in 2013 (common areas of residential blocks, covered pedestrian linkways, overhead bridges and within 5 m of bus stops), 2016 (parks) and 2017 (educational institutions, buses and taxis) on the monthly incidence rate of AMIs per 1 000 000 population.

RESULTS

We included 133 868 AMI reports from January 2010 to December 2019. Post-2013, there was a decrease in the AMI incidence trend (β=-0.6 per month, 95%CI -1.0 to -0.29) and 2097 (95% CI 2094 to 2100) more AMIs may have occurred without the extension. There was a significant step-decline in male AMIs and a non-significant step-increase in female AMIs post-2013. Those 65 years and older experienced a greater decline to the postlegislation 2013 trend (β=-5.9, 95% CI -8.7 to -3.1) compared with those younger (β=-0.4, 95% CI -0.6 to -0.2), while an estimated 19 591 (15 711 to 23472) additional AMI cases in those 65 years and above may have occurred without the extension. We found a step-increase in monthly AMI incidence post-2016 (β=14.2, 95%CI 3.3 to 25.0).

CONCLUSION

The 2013 smoke-free law extension to residential estates and other outdoor areas were associated with a decline in AMIs and those above the age of 65 years and men appeared to be major beneficiaries. Additional epidemiological evidence is required to support the expanded smoke-free legislation to parks, educational institutions, buses and taxis.

Impact of time-to-compression on out-of-hospital cardiac arrest survival outcomes: A national registry study

OBJECTIVE

We aimed to quantify the association of no-flow interval in out-of-hospital cardiac arrests (OHCA) with the odds of neurologically favorable survival and survival to hospital discharge/ 30th day. Our secondary aim was to explore futility thresholds to guide clinical decisions, such as prehospital termination of resuscitation.

METHODS

All OHCAs from 2012 to 2017 in Singapore were extracted. We examined the association between no-flow interval (continuous variable) and survival outcomes using univariate and multivariable logistic regressions. The primary outcome was survival with favorable cerebral performance (Glasgow-Pittsburgh Cerebral Performance Categories 1/2), the secondary outcome was survival to hospital discharge/ 30th day if not discharged. To determine futility thresholds, we plotted the adjusted probability of good neurological outcomes to no-flow interval.

RESULTS

12,771 OHCAs were analyzed. The per-minute adjusted OR when no-flow interval was incorporated as a continuous variable in the multivariable model was: good neurological function- aOR 0.98 (95%CI: 0.97-0.98); survival to discharge- aOR 0.98 (95%CI: 0.98-0.99). Taking the 1% futility of survival line gave a no-flow interval cutoff of 12 mins (NPV 99%, sensitivity 85% and specificity 42%) overall and 7.5 mins for witnessed arrests.

CONCLUSION

We demonstrated that prolonged no-flow interval had a significant effect on lower odds of favorable neurological outcomes, with medical futility occurring when no-flow interval was >12 mins (>7.5 mins for witnessed arrest). Our study adds to the literature of the importance of early CPR and EMS response and provided a threshold beyond traditional 'down-times', which could aid clinical decisions in TOR or OHCA management.

Functional and Mortality Outcomes with Medical and Surgical Therapy in Malignant Posterior Circulation Infarcts: A Systematic Review

BACKGROUND

There remains uncertainty regarding optimal definitive management for malignant posterior circulation infarcts (MPCI). While guidelines recommend neurosurgery for malignant cerebellar infarcts that are refractory to medical therapy, concerns exist about the functional outcome and quality of life after decompressive surgery.

OBJECTIVE

This study aims to evaluate the outcomes of surgical intervention compared to medical therapy in MPCI.

METHODS

In this systematic review, MEDLINE, Embase and Cochrane databases were searched from inception until 2 April 2021. Studies were included if they involved posterior circulation strokes treated with neurosurgical intervention and reported mortality and functional outcome data. Data were collected according to PRISMA guidelines.

RESULTS

The search yielded 6677 studies, of which 31 studies (comprising 723 patients) were included for analysis. From the included studies, we found that surgical therapy led to significant differences in mortality and functional outcomes in patients with severe disease. Neurological decline and radiological criteria were often used to decide the timing for surgical intervention, as there is currently limited evidence for preventative neurosurgery. There is also limited evidence for the superiority of one surgical modality over another.

CONCLUSION

For patients with MPCI who are clinically stable at the time of presentation, in terms of mortality and functional outcome, surgical therapy appears to be equivocal to medical therapy. Reliable evidence is lacking, and further prospective studies are rendered.

Clustering of Environmental Parameters and the Risk of Acute Ischaemic Stroke

Acute ischaemic stroke (AIS) risk on days with similar environmental profiles remains unknown. We investigated the association between clusters of days with similar environmental parameters and AIS incidence in Singapore. We grouped calendar days from 2010 to 2015 with similar rainfall, temperature, wind speed, and Pollutant Standards Index (PSI) using k-means clustering. Three distinct clusters were formed 'Cluster 1' containing high wind speed, 'Cluster 2' having high rainfall, and 'Cluster 3' having high temperatures and PSI. We aggregated the number of AIS episodes over the same period with the clusters and analysed their association using a conditional Poisson regression in a time-stratified case-crossover design. Comparing the three clusters, Cluster 3 had the highest AIS occurrence (IRR 1.09; 95% confidence interval (CI) 1.05-1.13), with no significant difference between Clusters 1 and 2. Subgroup analyses in Cluster 3 showed that AIS risk was amplified in the elderly (≥65 years old), non-smokers, and those without a history of ischaemic heart disease/atrial fibrillation/vascular heart disease/peripheral vascular disease. In conclusion, we found that AIS incidence may be higher on days with higher temperatures and PSI. These findings have important public health implications for AIS prevention and health services delivery during at-risk days, such as during the seasonal transboundary haze.

Interplay between post-myocardial infarction ejection fraction and atrial fibrillation: implications for ischemic stroke

Funding Acknowledgements

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

Background

There are little data on the interplay between post-acute myocardial infarction (MI), left ventricular systolic dysfunction and atrial fibrillation (AF) and the impact on subsequent acute ischemic stroke (AIS), particularly among patients with moderately reduced ejection fraction (EF).

Purpose

We aimed to study the association between low EF, AF and the risk and severity of AIS.

Methods

This study linked national, population-based data from the Singapore Myocardial Infarction Registry with the Singapore Stroke Registry from 2007 to 2018. The EF and AF status were recorded during the index MI hospitalization. Patients were grouped based on an EF of ≥50% or <50%. An additional grouping of patients with AMI in 2008 to 2018 and EF of ≥50% (normal EF), 40-49% (mildly reduced EF) or <40% (reduced EF) was done. The primary outcome of interest was the risk of developing an AIS after an AMI. The secondary outcome of interest was the National Institute of Health Stroke Scale (NIHSS) across the different strata of EF among AMI patients with subsequent AIS.

Results

There were 64512 patients available for analysis. The median age was 65.7 and 69.5% were male. The median duration from MI to AIS was 16.9 (IQR 1.6-46.1) months. Low EF <40% was independently associated with subsequent AIS (adjusted HR 1.18, 95% CI 1.10-1.27), as was EF 40-49% (adjusted HR 1.16, 95% CI 1.06-1.27). Among patients with AF, EF<50% was not a statistically significant predictor of AIS (adjusted HR 1.08, 95% CI 0.96-1.23). In patients without AF, the mildly reduced EF group had an increased aHR of AIS of 1.18 (95% CI 1.06-1.31), but not those with AF (aHR 1.03, 95% CI 0.87-1.23). The cubic spline curves of continuous EF against relative hazard for stroke stratified by presence of AF is shown in Figure 1. Patients with low EF without AF had highest median NIHSS score during subsequent AIS (EF <40% NIHSS 6-9; EF 40-49% NIHSS 4; EF ≥50% NIHSS 4).

Conclusions

Reduced and moderately reduced EF post-MI was independently associated with subsequent AIS and was associated with increased AIS severity in patients without AF but not in those with AF. Further research is needed to mitigate the risk of late AIS among post-MI patients with reduced EF along with AF.

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<0.01; high SHI: aOR 1.933, 95% CI 1.669–2.240, p<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<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).

Long term survival and disease burden from out-of-hospital cardiac arrest: a population-based cohort study

Background

Long-term outcomes of out-of-hospital cardiac arrest (OHCA) are important to evaluate the overall health burden of OHCA on society. The concept of disability-adjusted life years (DALY) have recently been utilised to measure disease burden in OHCA, but data in an Asian cohort remains limited. We aimed to quantify and identify predictors of long-term survival (up to 10 years follow up) in patients with OHCA, as well as to quantify the annual disease burden of OHCA estimated using DALY in a national multi-ethnic Asian cohort.

Methods

We conducted an open cohort study through the linkage of the Pan-Asian Resuscitation Outcomes Study and the Singapore Registry of Births and Deaths from 2010 to 2020 in Singapore [1]. We quantified long-term survival using the standardised mortality ratio (SMR) for each year of follow up and the annual disease burden using DALY. Predictors of long-term survival were identified using cox-proportional hazards models. Kaplan-Meier survival curves were constructed for the overall population, and by key characteristics. The proportion surviving (and 95% CI) was calculated for up to eight years post-OHCA.

Results

We included 802 cases in the analysis. The mean age was 56.0 (SD 17.8), 631 cases (78.7%) were male, and the majority (552 cases, 68.8%) were of Chinese ethnicity (Table 1). The proportion surviving at one year of follow up was 0.84 (95% CI: 0.81–0.87), at five years of follow up was 0.68 (95% CI 0.65–0.72), and at ten years of follow up was 0.62 (95% CI 0.57–0.67) (Figure 1). Age at arrest (HR 1.03, 95% CI: 1.02–1.04, p<0.001), shockable first arrest rhythm (HR 0.75, 95% CI: 0.52–0.93, p=0.015) and Cerebral Performance Category (CPC) (HR 4.62, 95% CI: 3.17–6.75, p<0.001) were independently associated with mortality (Figure 2, 3). At one year, the SMR was 14.9 (95% CI: 12.5–17.8), and this decreased to 1.2 (95% CI: 0.7–1.8) at three years, and 0.4 (95% CI: 0.2–0.8) at five years (Figure 4). The top three causes of death after OHCA based on ICD10 categories were pneumonia, chronic ischemic heart disease, and acute myocardial infarction. The total DALY increased from 304.1 in 2010 to 849.7 in 2015, followed by decreasing to 547.1 in 2018. The mean DALY decreased from 12.162 in 2010 to 3.599 in 2018.

Conclusions

Age at arrest and CPC category was independently associated with higher risk of mortality, while a shockable first arrest rhythm was independently associated with a lower risk of mortality in long-term OHCA survivors. Initial survivors of OHCA have an increased mortality rate compared to the general population for the first three years, but normalises to that of the general population subsequently, while the annual disease burden of OHCA quantified using DALY showed decreasing trends from 2010 to 2018. Further improvements in the surveillance and management of OHCA may be warranted to improve the long-term survivorship and decrease the burden of disease of OHCA globally.

Funding Acknowledgement

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

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.

The use of colchicine as an anti-inflammatory agent for stroke prevention in patients with coronary artery disease: a systematic review and meta-analysis

OBJECTIVE

The primary objective is to evaluate the use of colchicine as an anti-inflammatory agent for stroke prevention in patients with coronary artery disease.

BACKGROUND

There has been a rising number of randomized controlled trials conducted in patients with coronary artery disease on the use of colchicine in reducing cardiovascular complications. Recent publications suggest colchicine reduces the risk of stroke and other cardiovascular events.

METHODS

We performed a systematic review of known trials in the current literature to characterize the clinical characteristics and outcomes of colchicine treatment in patients with coronary artery disease. A literature search was performed in PubMed, Embase and SCOPUS using a suitable keyword search strategy from inception to 4 June 2021. All studies evaluating cardiovascular outcomes of colchicine treatment in patients with coronary artery disease were included.

RESULTS

The systemic review included 5 randomized controlled trials assessing a total of 11,790 patients. Majority of studies used a colchicine dosing regimen of 0.5 mg once daily, with the median follow-up duration ranging from 6 to 36 months. Meta-analytic estimates for stroke incidence highlighted a statistically significant benefit for patients that were administered colchicine compared to placebo (OR 0.47, 95% CI 0.27-0.81, p = 0.006), and a non-significant benefit for myocardial infarction. There was no significant association between colchicine treatment and the adverse effects of gastrointestinal symptoms and myopathy/myalgia.

CONCLUSIONS

The use of colchicine reduces the risk of stroke in patients with a history of coronary artery disease, without a significant increase in gastrointestinal and myopathy/myalgia adverse effects.

Evaluating the safety and efficacy of intravenous thrombolysis for acute ischemic stroke patients with a history of intracerebral hemorrhage: a systematic review and meta-analysis

Previous intracerebral hemorrhage (ICH) is labelled as a contraindication for the use of intravenous tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS) based on expert opinion. However, there is a paucity of data available regarding the benefits and risks of IV-tPA in this population. Recent small retrospective cohort studies reporting its off-label use suggest it may be beneficial. This study aims to investigate the safety and efficacy of IV-tPA in AIS patients with previous ICH. We performed a systematic review and meta-analysis of studies reporting on IV-tPA use in AIS patients with and without previous ICH. We searched Embase, PubMed and Cochrane Library from inception to 20 April 2021. Outcomes measured included symptomatic ICH (sICH), 3-month modified Rankin Scale (mRS) score, and 3-month mortality. We included seven retrospective cohort studies comprising 5760 AIS patients who had received IV-tPA, of which 134 had previous ICH. There was no significant difference in the odds of sICH (OR 1.57, 95% CI 0.78-3.15, p = 0.21) and 3-month mRS (mRS 0-1: OR 0.78, 95% CI 0.37-1.65, p = 0.52; mRS 0-2: OR 1.07, 95% CI 0.36-3.15, p = 0.90) between patients with and without previous ICH. There was a trend towards higher 3-month mortality in patients with previous ICH (OR 1.69, 95% CI 0.98-2.91, p = 0.06), although this did not reach statistical significance. The use of IV-tPA in AIS patients with previous ICH was not associated with an increased risk of sICH or disability at 3 months. Further larger studies are needed to establish the safety and efficacy of IV-tPA use in this population.

Effect of remote ischemic preConditioning on liver injury in patients undergoing liver resection: the ERIC-LIVER trial

OBJECTIVE

Novel hepatoprotective strategies are needed to improve clinical outcomes during liver surgery. There is mixed data on the role of remote ischemic preconditioning (RIPC). We investigated RIPC in partial hepatectomy for primary hepatocellular carcinoma (HCC).

METHODS

This was a Phase II, single-center, sham-controlled, randomized controlled trial (RCT). The primary hypothesis was that RIPC would reduce acute liver injury following surgery indicated by serum alanine transferase (ALT) 24 h following hepatectomy in patients with primary HCC, compared to sham. Patients were randomized to receive either four cycles of 5 min/5 min arm cuff inflation/deflation immediately prior to surgery, or sham. Secondary endpoints included clinical, biochemical and pathological outcomes. Liver function measured by Indocyanine Green pulse densitometry was performed in a subset of patients.

RESULTS

24 and 26 patients were randomized to RIPC and control groups respectively. The groups were balanced for baseline characteristics, except the duration of operation was longer in the RIPC group. Median ALT at 24 h was similar between groups (196 IU/L IQR 113.5-419.5 versus 172.5 IU/L IQR 115-298 respectively, p = 0.61). Groups were similar in secondary endpoints.

CONCLUSION

This RCT did not demonstrate beneficial effects with RIPC on serum ALT levels 24 h after partial hepatectomy.

Left Atrial Volume Index Predicts New-Onset Atrial Fibrillation and Stroke Recurrence in Patients with Embolic Stroke of Undetermined Source

INTRODUCTION

It is unclear which surrogate of atrial cardiopathy best predicts the risk of developing a recurrent ischemic stroke in embolic stroke of undetermined source (ESUS). Left atrial diameter (LAD) and LAD index (LADi) are often used as markers of left atrial enlargement in current ESUS research, but left atrial volume index (LAVi) has been found to be a better predictor of cardiovascular outcomes in other patient populations.

OBJECTIVE

We aim to compare the performance of LAVi, LAD, and LADi in predicting the development of new-onset atrial fibrillation (AF) and stroke recurrence in ESUS.

METHODS

Between October 2014 and October 2017, consecutive patients diagnosed with ESUS were followed for new-onset AF, ischemic stroke recurrence, and a composite outcome of occult AF and stroke recurrence. LAVi and LADi were measured by transthoracic echocardiogram; "high" LAVi was defined as ≥35 mL/m2 in accordance with American Society of Echocardiography guidelines.

RESULTS

185 ischemic stroke patients with ESUS were recruited and followed for a median duration of 2.1 years. Increased LAVi was associated with new-onset AF detection (aOR 1.08; 95% CI 1.03-1.14; p = 0.003) and stroke recurrence (aOR 1.05; 95% CI 1.01-1.10; p = 0.026). Patients with "high" LAVi had a higher likelihood of developing a composite of AF detection and stroke recurrence (HR 3.45; 95% CI 1.55-7.67; p = 0.002). No significant association was observed between LADi and either occult AF or stroke recurrence.

CONCLUSIONS

LAVi is associated with new-onset AF and stroke recurrence in ESUS patients and may be a better surrogate of atrial cardiopathy.

Containing COVID-19 in the Emergency Department: The Role of Improved Case Detection and Segregation of Suspect Cases

OBJECTIVES

Patients with COVID-19 may present with respiratory syndromes indistinguishable from common viruses. This poses a challenge for early detection during triage in the emergency department (ED). Over a 3-month period, our ED aimed to minimize nosocomial transmission by using broader suspect case criteria for better detection and using appropriate personal protective equipment (PPE) for health care workers (HCWs).

METHODS

All ED admissions with respiratory syndromes over a 3-month period were tested for COVID-19. The sensitivity and specificity of screening criteria in detecting COVID-19 were assessed. A risk-stratified approach was adopted for PPE usage in the ED, based on high-risk "fever areas" and lower-risk zones. When a case of COVID-19 was confirmed, surveillance was conducted for potentially exposed patients and HCWs.

RESULTS

A total of 1,841 cases presenting with respiratory syndromes required admission over the study period. Among these, 70 cases of COVID-19 were subsequently confirmed. The majority (84.2%, 59/70) were detected at ED triage because they fulfilled suspect case criteria. Of these, 34 met the official screening criteria; an additional 25 were detected by the broader internal screening criteria. Over the 12-week period, the cumulative sensitivity of internal screening criteria was 84.3% (95% confidence interval [CI] = 73.6% to 91.9%), whereas the sensitivity of the official screening criteria was 48.6% (95% CI = 36.4% to 60.8%). Given the broadened internal criteria, the preexisting ED "fever area" was insufficient and had to be expanded. However, there were no cases of nosocomial transmission from intra-ED exposure, despite extensive surveillance.

CONCLUSION

Frontline physicians need to be given leeway to decide on the disposition of cases based on clinical suspicion during an ongoing outbreak of COVID-19. If a broader criterion is used at ED triage, ED facilities and isolation facilities need to be readied to accommodate a surge of suspect cases. Usage of appropriate PPE is essential in minimizing nosocomial transmission.

P5482The lipid paradox in patients with non-ST elevation and ST elevation myocardial infarction and percutaneous coronary intervention

Background/Introduction

Elevated levels of low-density lipoprotein (LDL-C) and triglycerides (TG) are well-described risk factors for the development of acute myocardial infarction (MI). Despite these well-established associations, previous studies have described the existence of a “lipid paradox” in acute MI patients – Patients paradoxically have worse outcomes despite having lower LDL-C and TG levels.

Purpose

We conducted this study to clarify the relationship of the lipid paradox and clinical outcomes amongst non-ST elevation (NSTEMI) and ST elevation MI (STEMI) patients in patients who have had percutaneous coronary intervention.

Methods

We included all acute MI patients reported to the Singapore Myocardial Infarction Registry from 2007 to 2013 who have had percutaneous coronary intervention. This information was linked to the national claims database to obtain the final discharge diagnosis for re-hospitalization outcomes. Exposure of interest was the lipid profile obtained within 72 hours of the acute MI (LDL-C, TG; Total cholesterol [TC]; high-density lipoprotein [HDL-C]). Primary outcomes were all-cause mortality during hospitalization, within 30-days and within 1-year. Secondary outcomes were re-hospitalization within 1-year for heart failure, stroke and MI.

Results

There were 8988 NSTEMI and 12453 STEMI cases available for analysis (n=21441). The NSTEMI patients were older (60.3 years vs 57.6 years, p<0.001) and more likely to be female (15.1% vs 22.6%, p<0.001). In the NSTEMI subgroup, a lower LDL-C was paradoxically associated with better outcomes for death during hospitalization, death within 30 days from MI onset and death within 1 year from MI onset (all p<0.001) across the various LDL-C levels. Adjustment for demographic variables, co-morbidities and MI characteristics eliminated this paradox. However, in the STEMI subgroup, the lipid paradox for LDL-C persisted for all primary outcome endpoints after adjustment. In the STEMI patients, a lower HDL-C also appeared to be protective. An elevated TG level did not appear to be protective in both NSTEMI and STEMI patients after adjustment.

Conclusion(s)

An elevated LDL-C appears to be a protective prognostic marker in STEMI but not NSTEMI patients who have undergone percutaneous coronary intervention. This difference may be due to differing underlying pathophysiological mechanisms between the 2 populations.

Platelet inhibition to target reperfusion injury trial: Rationale and study design

BACKGROUND

In ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI), current oral P2Y12 platelet inhibitors do not provide maximal platelet inhibition at the time of reperfusion. Furthermore, administration of cangrelor prior to reperfusion has been shown in pre-clinical studies to reduce myocardial infarct (MI) size. Therefore, we hypothesize that cangrelor administered prior to reperfusion in STEMI patients will reduce the incidence of microvascular obstruction (MVO) and limit MI size in STEMI patients treated with PPCI.

METHODS

The platelet inhibition to target reperfusion injury (PITRI) trial, is a phase 2A, multi-center, double-blinded, randomized controlled trial, in which 210 STEMI patients will be randomized to receive either an intravenous (IV) bolus of cangrelor (30 μg/kg) followed by a 120-minute infusion (4 μg/kg/min) or matching saline placebo, initiated prior to reperfusion (NCT03102723).

RESULTS

The study started in October 2017 and the anticipated end date would be July 2020. The primary end-point will be MI size quantified by cardiovascular magnetic resonance (CMR) on day 3 post-PPCI. Secondary endpoints will include markers of reperfusion, incidence of MVO, MI size, and adverse left ventricular remodeling at 6 months, and major adverse cardiac and cerebrovascular events.

SUMMARY

The aim of the PITRI trial is to assess whether cangrelor administered prior to reperfusion would reduce acute MI size and MVO, as assessed by CMR.

The Relationship Between Ambient Air Pollution and Acute Ischemic Stroke: A Time-Stratified Case-Crossover Study in a City-State With Seasonal Exposure to the Southeast Asian Haze Problem

STUDY OBJECTIVE

Studies are divided on the short-term association of air pollution with stroke. Singapore is exposed to seasonal transboundary haze. We aim to investigate the association between air pollution and stroke incidence in Singapore.

METHODS

We performed a time-stratified case-crossover analysis on all ischemic stroke cases reported to the Singapore Stroke Registry from 2010 to 2015. Exposure on days was compared with control days on which exposure did not occur. Control days were chosen on the same day of the week earlier and later in the same month in the same year. We fitted a conditional Poisson regression model to daily stroke incidence that included Pollutant Standards Index and environmental confounders. The index was categorized according to established classification (0 to 50=good, 51 to 100=moderate, and ≥101=unhealthy). We assessed the relationship between stroke incidence and Pollutant Standards Index in the entire cohort and in predetermined subgroups of individual-level characteristics.

RESULTS

There were 29,384 ischemic stroke cases. Moderate and unhealthy Pollutant Standards Index levels showed association with stroke occurrence, with incidence risk ratio 1.10 (95% confidence interval 1.06 to 1.13) and 1.14 (95% confidence interval 1.03 to 1.25), respectively. Subgroup analyses showed generally significant association, except in Indians and nonhypertensive patients. The association was significant in subgroups aged 65 years or older, women, Chinese, nonsmokers and those with history of diabetes, hypertension, and hyperlipidemia. Stratified by age and smoking, the risk diminished in smokers of all ages. Risk remained elevated for 5 days after exposure.

CONCLUSION

We found a short-term elevated risk of ischemic stroke after exposure to air pollution. These findings have public health implications for stroke prevention and emergency health services delivery.

Is Hepatorenal Syndrome a Diagnosis for the Emergency Physician

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