Chest pain in the absence of obstructive coronary artery disease (CAD) is common in
women; it is frequently associated with debilitating symptoms and repeated evaluations
and may be caused by coronary microvascular dysfunction. However, the prevalence and
determinants of microvascular dysfunction in these women are uncertain.
We measured coronary flow velocity reserve (coronary velocity response to intracoronary
adenosine) to evaluate the coronary microvasculature and risk factors for atherosclerosis
in 159 women (mean age, 52.9 years) with chest pain and no obstructive CAD. All women
were referred for coronary angiography to evaluate their chest pain as part of the
Women's Ischemia Syndrome Evaluation (WISE) study.
Seventy-four (47%) women had subnormal (<2.5) coronary flow velocity reserve suggestive
of microvascular dysfunction (mean, 2.02 +/- 0.38); 85 (53%) had normal reserve (mean,
3.13 +/- 0.64). Demographic characteristics, blood pressure, ventricular function,
lipid levels, and reproductive hormone levels were not significantly different between
women with normal and those with abnormal microvascular function. Postmenopausal hormone
use within 3 months was significantly less prevalent among those with microvascular
dysfunction (40% vs 60%, P =.032). Age and number of years past menopause correlated
with flow velocity reserve (r = -0.18, P =.02, and r = -0.30, P <.001, respectively).
No significant associations were identified between flow velocity reserve and lipid
and hormone levels, blood pressure, and left ventricular ejection fraction.
Coronary microvascular dysfunction is present in approximately one half of women with
chest pain in the absence of obstructive CAD and cannot be predicted by risk factors
for atherosclerosis and hormone levels. Therefore, the diagnosis of coronary microvascular
dysfunction should be considered in women with chest pain not attributable to obstructive
CAD.