Results:

A total of 405 men and 813 women were included in the present study. Women were slightly older, and more likely to be Hispanic and nonwhite than men. Compared to men, women were also more frequently obese and hypertensive. However, women were less likely to use tobacco. Chest pain and dyspnea were also more frequent in women than men. The pretest clinical risk based on the gender-neutral modified Duke clinical risk score was higher among women than men (35% vs. 29%, respectively, p = 0.007). Left ventricular ejection fractions were slightly higher among women, although they were normal in both genders. Coronary microvascular dysfunction was highly prevalent both in men and women (51% and 54%, respectively; P [Fisher exact test] = 0.39; P [equivalence] = 0.0002). Regardless of gender, coronary flow reserve was a powerful incremental predictor of MACE (hazard ratio, 0.80 [95% confidence interval, 0.75-086] per 10% increase in coronary flow reserve; p < 0.0001), and resulted in favorable net reclassification improvement = 0.280 [95% confidence interval, 0.049-0.512]), after adjustment for clinical risk and ventricular function. In a subgroup (n = 404; 307 female/97 male) without evidence of coronary artery calcification on gated CT imaging, coronary microvascular dysfunction was common in both genders, despite normal stress perfusion imaging and zero coronary artery calcification (44% of men vs. 48% of women; P [Fisher exact test] = 0.56; P [equivalence] = 0.041).