Study Reveals Increased Risk of Myocardial Infarction in Cold Weather for MINOCA Patients

The research, published in the European Heart Journal, revealed that cold weather may increase the susceptibility to myocardial infarction with non-obstructive coronary arteries compared to myocardial infarction resulting from obstructive coronary artery disease.

Myocardial infarction, commonly known as a heart attack, occurs when blood flow to the heart is severely reduced or blocked, leading to damage in the heart muscle. Traditionally, MI is associated with obstructive coronary artery disease, characterized by plaque buildup in the arteries. However, patients with MINOCA experience heart attacks despite the absence of significant blockages, suggesting that other factors contribute to their condition. One such factor is non-optimal ambient temperature, recognized as a significant non-traditional risk factor for acute MI. However, there is limited understanding of how low temperatures may differentially affect myocardial infarction with obstructive coronary artery disease (MI-CAD) and MINOCA patients.

To fill this knowledge gap, Renjie Chen, Fudan University, Shanghai, China, and colleagues conducted a nationwide, time-stratified, case-crossover investigation from 2015 to 2021 using the Chinese Cardiovascular Association database- chest Pain Center Registry. Meteorological data were sourced from a well-established satellite-based model, with daily exposure levels assigned based on each patient's onset of myocardial infarction. A conditional logistic regression model, integrated with distributed lag non-linear models spanning 10 days, was employed to assess the exposure-response relationships.

The study led to the following findings:

• A total of 83,784 MINOCA patients and 918,730 MI-CAD patients participated in the study.
• The risk of both conditions related to low temperatures was evident starting at a 2-day lag and continued for up to 1 week.
• Extremely low temperatures were linked to a notably higher odds ratio (OR) for MINOCA, with an OR of 1.58, compared to MI-CAD, which showed an unmatched OR of 1.32 and an equally matched OR of 1.25 when adjusted for age and sex, using reference temperatures of 30°C, 35°C, and 30°C.
• Stronger associations with MINOCA were identified among patients aged ≥65, females, and those living in the southern regions.
• There were no significant differences in the effects of high temperatures on MINOCA versus MI-CAD.

"The nationwide study emphasizes the heightened vulnerability of MINOCA patients to low ambient temperatures in contrast to MI-CAD patients," the researchers concluded.

Reference:

Huang, J., He, Q., Jiang, Y., Wong, J. M., Li, J., Liu, J., Wang, R., Chen, R., Dai, Y., & Ge, J. Low ambient temperature and incident myocardial infarction with or without obstructive coronary arteries: A Chinese nationwide study. European Heart Journal. https://doi.org/10.1093/eurheartj/ehae711