[Correspondence] Cardiovascular outcomes in coronary microvascular dysfunction: the Multicenter FLOW-CMD Registry

AI Summary

The multicenter FLOW-CMD Registry study identified coronary microvascular dysfunction in 16.3% of patients, with worse prognosis in patients lacking obstructive epicardial coronary artery disease. These findings highlight significant cardiovascular risks even in patients without major arterial blockages.

In their recent Article,1 Joo Myung Lee and colleagues used bolus thermodilution (coronary flow reserve [CFR] <2·0 and the index of microcirculatory resistance [IMR] ≥25) to define coronary microvascular dysfunction and found it in 163 (16·3%) of 1003 patients. One in five of these cases were in people with obstructive epicardial coronary artery disease, but 10% occurred in those without obstructive epicardial coronary artery disease. In this latter group, prognoses were worse, with adverse events occurring in a quarter (ten of 40) of those with coronary microvascular dysfunction compared with less than a tenth in those without (30 of 390 patients; hazard ratio 3·45 [95% CI 1·69–7·06]; p=0·0003).