Stress-induced MI linked to severity of coronary plaque in men, not women

The patients also underwent a mental stress test, which evaluated myocardial blood flow in response to a stressful situation (a public speaking task). Based on a reduction in myocardial blood flow during this stressful challenge, 17 percent of patients were classified as having MSIMI.

Key Findings:

• Women had a higher rate of MSIMI (20 percent) than men (15 percent).


• Twenty-seven percent of patients had conventional stress-induced myocardial ischemia (CSIMI).


• Only 10 percent of patients had both MSIMI and CSIMI.


• In both men and women, the presence of CSIMI was associated with greater obstructive coronary disease severity.


• For each one-unit increase in severity score, the likelihood of CSIMI increased by about 50 percent, after adjustment for other factors.


• In contrast, the presence of MSIMI was associated with more severe plaque buildup only in men: for each one-unit increase in severity score, the likelihood of MSIMI nearly doubled.


• For women, MSIMI was unrelated to obstructive coronary disease severity.

"There is growing evidence that psychosocial stressors may promote the development and progression of cardiovascular disease in susceptible individuals," write the authors. However, the relationship between MSIMI and obstructive coronary disease, which means blockages in the major coronary arteries supplying blood to the heart muscle, has been unclear. Women are more likely than men to develop myocardial ischemia without coronary obstruction.

The results support the hypothesis that MSIMI may develop via different mechanisms in women versus men. Consistent with previous findings on sex differences in heart disease, it may be that MSIMI in women mainly reflects abnormalities other than blockage of the coronary arteries, such as malfunction of the smaller coronary blood vessels (microcirculatory dysfunction).

The sex differences may have important implications for understanding sex-specific vascular effects of psychological stress in general and the mechanisms of MSIMI in particular since most previous studies of this issue have focused on men.

"These results suggest that MSIMI must be driven by alternative mechanisms especially among women, and provide motivation for further research to understand sex-specific mechanisms for the effects of mental stress on myocardial ischemia and long-term outcomes." conclude the authors.