Sex differences in mental stress-induced myocardial ischemia in young survivors of an acute myocardial infarction

Abstract

Objectives: Emotional stress may disproportionally affect young women with ischemic heart disease. We sought to examine whether mental stress-induced myocardial ischemia (MSIMI), but not exercise-induced ischemia, is more common in young women with previous myocardial infarction (MI) than in men.

Methods: We studied 98 post-MI patients (49 women and 49 men) aged 38 to 60 years. Women and men were matched for age, MI type, and months since MI. Patients underwent technetium-99m sestamibi perfusion imaging at rest, after mental stress, and after exercise/pharmacological stress. Perfusion defect scores were obtained with observer-independent software. A summed difference score (SDS), the difference between stress and rest scores, was used to quantify ischemia under both stress conditions.

Results: Women 50 years or younger, but not older women, showed a more adverse psychosocial profile than did age-matched men but did not differ for conventional risk factors and tended to have less angiographic coronary artery disease. Compared with age-matched men, women 50 years or younger exhibited a higher SDS with mental stress (3.1 versus 1.5, p = .029) and had twice the rate of MSIMI (SDS ≥ 3; 52% versus 25%), whereas ischemia with physical stress did not differ (36% versus 25%). In older patients, there were no sex differences in MSIMI. The higher prevalence of MSIMI in young women persisted when adjusting for sociodemographic and life-style factors, coronary artery disease severity, and depression.

Conclusions: MSIMI post-MI is more common in women 50 years or younger compared with age-matched men. These sex differences are not observed in post-MI patients who are older than 50 years.

Figure 1

Example of mental and physical stress myocardial perfusion imaging in one of the women enrolled in the study. The horizontal short axis slices in row A were obtained after mental stress and show a clear perfusion defect in the infero-lateral wall of the left ventricle (yellow arrows). The images in row B were obtained after physical stress; the perfusion defect is much smaller and barely visible. The images in row C were obtained at rest and are very similar to those obtained after physical stress test (row B). The bull's eyes in row D show the infero-lateral perfusion defect after mental stress on the left and after physical stress on the right. The sum stress score was 16 for the mental stress and 11 for the physical stress.

Figure 2

Sex differences in mental stress ischemia (SDS ≥3) and physical stress ischemia (SDS ≥4) according to age group. Numbers at the bottom of each bar are number of patients of ischemia over the total sample in each group.