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Stress-induced ischaemia after heart attack: are women more vulnerable?

By Jane Lewis
After a myocardial infarction (MI), young and middle-aged women are twice as likely as similarly aged men to develop ischaemia with exposure to stress, despite having less severe obstructive coronary artery disease, new research suggests.

Microvascular dysfunction and peripheral vasoconstriction in women appeared to be related to mental stress-induced myocardial ischaemia but not in men, the study also found.

Speaking to Medicine Today, Dr Jennifer Johns, cardiologist at Austin Hospital, Melbourne, and National Heart Foundation President, said the study might partially explain the worse outcomes seen in young women after myocardial infarction.

Published in Circulation, the US study included two groups: 306 patients aged 61 years or younger (150 women and 156 men) hospitalised for MI in the previous eight months, and 112 sex- and age-matched community controls. Compared with men with MI, women in the MI group had a more adverse sociodemographic and psychosocial profile, and were more likely to be black.

Women with MI experienced twice the rate of myocardial ischaemia of men with MI, both with mental stress and with conventional stress (22% vs 11%, and 31% vs 16%, respectively). Sex differences in inducible ischaemia could not be explained by psychosocial and clinical risk factors, nor by vascular responses to stress.

However, microvascular dysfunction and peripheral vasoconstriction during mental stress were related to mental stress-induced myocardial ischaemia in women but not in men, leading the authors to suggest that ‘stressful exposures may play an important role in this group by inducing myocardial ischemia through sympathetically mediated effects on the microcirculation.’

Dr Johns said that although the study added to existing data, it also had important limitations, including that the induced ischaemia in all groups was relatively mild and there were no clinical endpoints. The applicability of the study’s findings to the Australian population was also questionable with the study based on a US population and a high proportion of black women in the MI group.
Circulation 2018; 137: 794-805.