Silent ischaemia common among women with coronary microvascular dysfunction

Ambulatory ischaemia, particularly silent ischaemia (SI), occurs commonly among women with coronary microvascular dysfunction (CMD), a new study has found.

Researchers enrolled 36 women with CMD, with an average age of 57±10 years, who were made to undergo 24-hour 12-lead ambulatory electrocardiogram monitoring following discontinuation of anti-ischaemia medication. Symptoms and evidence of ischaemia were recorded. Sixteen age-matched controls (mean age, 51±20 years) were also enrolled.

Fourteen women in the CMD group had at least one episode of ST depression, yielding a rate of 39 percent. There were 26 episodes in total. In comparison, no such cases were reported in the matched controls. The resulting difference was statistically significant (p=0.002).

Of the 26 ST depression episodes, only three (12 percent) were symptomatic; the remaining 23 episodes were silent. The mean and peak heart rate at the onset of SI was 96±13 and 117±16 bpm, respectively.

Coronary reactivity testing (CRT) measures were comparable between those with and without ambulatory ischaemia. CRT likewise did not differ between patients with and without SI, such that those who had ≥2 CRT abnormalities did not show a greater burden of SI episodes than comparators with <2 abnormalities.

“To our knowledge, this is the first report on prevalence of SI in a population of women who have undergone CRT to diagnose CMD,” researchers said.

“Given the previously established adverse prognostic significance of SI in obstructive coronary artery disease, and the poor outcomes associated with CMD, clinical trials evaluating anti-ischemic medications should be considered in the CMD population,” they added.