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)

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.