MicroRNAs to take the place of collateral flow index measurements and Rentrop scoring?—Reply to Papageorgiou et al.

We thank Papageorgiou et al. for their thoughtful comments on our recent publication regarding circulating microRNAs (miRNAs) associated with coronary collateral artery capacity (1). The benefits of a vast collateral network have been widely accepted to prevent mortality in patients with chronic stable coronary artery disease (CAD) (2,3). Identifying patients with a limited collateral network can in turn distinguish patients at risk to substantial debilitation from adverse cardiac events. Nonetheless, current methods to identify patients with insufficient collateralization are limited to invasive intracoronary collateral flow index (CFI) measurements or angiographic grading (4). Clinical parameters associated with collateral development have been identified (5). However, there remained a lack of biomarkers to discriminate between patients with sufficient or insufficient collateralization.