Coronary microvascular reactivity is only partially predicted by atherosclerosis risk factors or coronary artery disease in women evaluated for suspected ischemia: Results from the NHLBI Women's Ischemia Syndrome Evaluation (WISE)

Background: Altered coronary reactivity is frequent in women with findings of myocardial ischemia without significant obstructive disease. This suggests a defect in coronary microvascular function. The adenosine-related component of this altered reactivity has been described in male and mixed gender populations, while the factors influencing this component of coronary reactivity in symptomatic women have received limited attention. Accordingly, the relationship between adenosine-related microvascular coronary reactivity and risk factors in symptomatic women evaluated for suspected ischemia remains uncertain. Hypothesis: Abnormal coronary microvascular reactivity to adenosine is predicted by atherosclerosis risk factors in women. Methods: As part of the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE), we investigated the relationship between risk factors and coronary microvascular reactivity as flow velocity reserve to intracoronary adenosine (CFVRAdo) in 210 women referred for angiography to evaluate suspected ischemia. Results: Univariate analyses identified associations between CFVRAdo and multiple risk conditions; however, after adjusting for age, none remained significant. The best multivariable model using combinations of risk conditions to predict CFVRAdo yielded an R-2 of only 0.18. Conclusions: Among women with suspected ischemia, risk factors account for < 20% of observed variability in CFVRAdo. Therefore, other as yet unidentified factors must primarily account for coronary microvascular reactivity to adenosine.