I read the study by Di Franco et al comparing asymptomatic subjects with exercise-induced ST-segment depression and normal coronary arteries to patients with microvascular angina. Coronary blood flow response to adenosine, coronary blood flow response to cold pressor testing, and flow-mediated dilatation were similar in the 2 groups, suggesting an identical condition in both. The main clinical characteristics of the members of the 2 groups and those of the healthy control group were summarized, and no differences were found. The investigators did not find any difference regarding drug therapy between the 2 groups. However, from Table 1, it is evident that members of the healthy control group took on average 0.9 medications per member, those of the asymptomatic group took on average 1.8 medications per member, and those of the microvascular angina group took on average 2.6 medications per member. The differences were thus 0.9 and 0.8, respectively. If 0.8 is seen as a negligible difference, then 0.9 should also be considered a negligible difference, using the same criteria, and a statement that no difference can be seen between healthy controls and asymptomatic subjects regarding drug therapy could be made. If the healthy control group consisted of subjects not taking any medications, the conclusion regarding the absence of a difference in drug therapy between the microvascular angina group and the asymptomatic group could not be so directly questioned. Furthermore, information on the normality of the coronary arteries in the healthy control group is missing.

Nevertheless, an intriguing situation is presented. Two groups with the same condition, 1 symptomatic and 1 asymptomatic, are presented. Members of the symptomatic group are classified as having microvascular angina, and those of asymptomatic group are classified as “false-positives.” Members of the 2 groups were treated with the same drugs. Presenting available data as Thrombolysis In Myocardial Infarction (TIMI) frame count and exercise test variables (rate-pressure product at 1-mm ST-segment depression and at peak exercise and time) could further underline the equality of the microvascular angina group and the asymptomatic group.