Associations between Ambient Temperature and Acute Myocardial Infarction

Impact of Climate on the Incidence of Acute Coronary Syndrome - Differences Between Japan and Thailand

Background: Although there are many reports of temperature being associated with the onset of acute coronary syndrome (ACS), few studies have examined differences in ACS due to climatic differences between Japan and Thailand. The aim of this joint Japan-Thailand study was to compare patients with myocardial infarction in Japanese and Thai hospitals in different climates. Methods and Results: We estimated the climate data in 2021 for the Wakayama Prefecture and Chonburi Province, two medium-sized cities in Japan and Thailand, respectively, and ACS patients who were treated at the Wakayama Medical University (WMU) and Burapha University Hospital (BUH), the two main hospitals in these provinces (ACS patient numbers: WMU, n=177; BUH, n=93), respectively. In the Chonburi Province, although the average temperature was above 25℃, the number of ACS cases in BUH varied up to threefold between months (minimum: July, 4 cases; maximum: October, 14 cases). In Japan and Thailand, there was a mild to moderate negative correlation between temperature-atmospheric pressure at the onset of ACS, but different patterns for temperature-humidity (temperature-atmospheric pressure, temperature-humidity, and atmospheric pressure-humidity: correlation index; r=-0.561, 0.196, and -0.296 in WMU vs. r=-0.356, -0.606, and -0.502 in BUH). Conclusions: The present study suggests that other climatic conditions and factors, not just temperature, might be involved in the mechanism of ACS.

Long-term prognostic importance of high levels of sST2 in patient with AMI: a meta-analysis

OBJECTIVE

This meta-study aimed to assess the connection between soluble suppression of tumorigenicity 2 (sST2) and extended clinical outcomes in individuals diagnosed with acute myocardial infarction (AMI).

METHODS

We systematically collected pertinent literature from PubMed, Embase and Web of Science. The primary effect measures employed in this research were the hazard ratio and 95% confidence intervals. The quality and publication bias of included studies were evaluated. Subgroup analysis was conducted to explore the diversity in study outcomes.

RESULTS

This comprehensive meta-analysis ultimately encompassed thirteen studies, involving a total of 11,571 patients. Elevated levels of sST2 were identified as an adverse prognostic indicator, demonstrating a substantial association not only with overall mortality (combined HR 2.4, 95% CI 1.6-3.5, P < 0.01) but also with major adverse cardiovascular events (MACEs) (HR 2.5, 95% CI 1.5-4.2, P < 0.01). Subgroup analyses revealed that increased sST2 levels were linked to higher rates of all-cause mortality and MACEs in patients with ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), and other unselected subcategories of AMI.

CONCLUSION

Increased sST2 could predict the long-term prognosis in patients suffering from AMI.

Interplay between climate, pollution and COVID-19 on ST-elevation myocardial infarction in a large metropolitan region

BACKGROUND

Collective risk factors such as climate and pollution impact on the risk of acute cardiovascular events, including ST-elevation myocardial infarction (STEMI). There is limited data however on the precise temporal and independent association between these factors and STEMI, and the potentially interacting role of government policies against Coronavirus disease 2019 (COVID-19), especially for Latin America.

METHODS

We retrospectively collected aggregate data on daily STEMI admissions at 10 tertiary care centers in the Buenos Aires metropolitan area, Argentina, from January 1, 2017 to November 30, 2020. Daily measurements for temperature, humidity, atmospheric pressure, wind direction, wind speed, and rainfall, as well as carbon monoxide (CO), nitrogen dioxide, and particulate matter <10 µm (PM10), were retrieved. Exploratory analyses focused on key COVID-19-related periods (e.g. first case, first lockdown), and Stringency Index quantifying the intensity of government policy response against COVID-19.

RESULTS

A total of 1498 STEMI occurred over 1430 days, for an average of 0.12 STEMI per center (decreasing from 0.130 in 2018 to 0.102 in 2020, P=0.016). Time series analysis showed that lower temperature and higher concentration of CO and PM10 were all significantly associated with an increased rate of STEMI (all P<0.05), whereas COVID-19 outbreak, lockdown, and stringency of government policies were all inversely associated with STEMI (all P<0.05). Notably, environmental features impacted as early as 28 days before the event (all P<0.05), even if same or prior day associations proved stronger (all P<0.05). Multivariable analysis suggested that maximum temperature (P=0.001) and PM10 (P=0.033) were the strongest predictor of STEMI, even after accounting for COVID-19-related countermeasures (P=0.043).

CONCLUSIONS

Lower temperature and higher concentrations of CO and PM10 are associated with significant increases in the rate of STEMI in a large Latin American metropolitan area. The reduction in STEMI cases seen during the COVID-19 pandemic is at least in part mediated by improvements in pollution, especially reductions in PM10.

Transient increase in blood thrombogenicity may be a critical mechanism for the occurrence of acute myocardial infarction

Although the mechanism for the occurrence of acute myocardial infarction (MI) has been investigated by many pathological and clinical studies, it has not been adequately clarified yet. Although the disruption of vulnerable plaque is a well-known cause of acute MI, there are many silent plaque disruptions detected in the coronary artery by intravascular imaging studies. Therefore, many vulnerable plaques may disrupt and heal without causing acute MI. Some additional mechanisms other than the disruption of vulnerable plaque would be essential for the onset of acute MI. On the other hand, blood thrombogenicity would change dynamically due to circadian rhythms and many other factors. The combination of plaque and blood thrombogenicity would play an important and determinant role for the onset of acute MI.