Coronary flow velocity response to adenosine characterizes coronary microvascular function in women with chest pain and no obstructive coronary disease - Results from the pilot phase of the Women's Ischemia Syndrome Evaluation (WISE) study

OBJECTIVES We sought to develop and validate a definition of coronary microvascular dy sfunction in women with chest pain and no significant epicardial obstructio n based on adenosine-induced changes in coronary flow velocity (i.e., coron ary velocity reserve). BACKGROUND Chest pain is frequently not caused by fixed obstructive coronary artery di sease (CAD) of of large vessels in women. Coronary microvascular dysfunctio n is an alternative mechanism or chest pain that is more prevalent in women and is associated with attenuated coronary volumetric flow augmentation in response to hyperemic stimuli (i.e., abnormal coronary flow reserve). Howe ver, traditional assessment of coronary volumetric flow reserve is time con suming and not uniformly available. METHODS As part of the Women's Ischemia Syndrome Evaluation (WISE) study, 48 women with chest pam and normal coronary arteries or minimal coronary luminal irr egularities (mean stenosis = 7%) underwent assessment of coronary blood flo w reserve and coronary flow velocity reserve. Blood flow responses to intra coronary adenosine were measured using intracoronary Doppler ultrasonograph y and quantitative angiography RESULTS Coronary volumetric flow reserve correlated with coronary velocity reserve (Pearson correlation = 0.87, p < 0.001). In 29 (60%) women with abnormal co ronary microcirculation (mem coronary flow reserve = 1.84), adenosine incre ased coronary velocity by 89% (p < 0.001) but did not change coronary cross -sectional area. In 19 (40%) women with normal microcirculation (mean flow reserve = 3.24), adenosine increased coronary velocity and area by 179% (p < 0.001) and 17% (p < 0.001), respectively. A coronary velocity reserve thr eshold of 2.24 provided the best balance between sensitivity and specificit y (90% and 89%, respectively) for the diagnosis of microvascular dysfunctio n. In addition, failure of the epicardial coronary to dilate at least 9% wa s found to be a sensitive (79%) and specific (79%) surrogate marker of micr ovascular dysfunction CONCLUSIONS Coronary flow velocity response to intracoronary adenosine characterizes co ronary microvascular function in women with chest pain in the absence of ob structive CAD. Attenuated epicardial coronary dilation response to adenosin e may be a surrogate marker of microvascular dysfunction in women with ches t pain and no obstructive CAD. (C) 1999 by the American College of Cardiolo gy.