Quantitative myocardial blush grade reserve during pharmacologic hyperaemia: a way to perform a real wireless fractional flow reserve measurement in patients with coronary artery disease and intermediate coronary lesions.

Abstract

We investigated the relation between myocardial blush grade reserve (MBGreserve) and fractional flow reserve (FFR) measures. FFR is a marker of inducible myocardial ischaemia, which could guide percutaneous coronary intervention (PCI) and stent placement. However, it requires a pressure wire and is associated with additional costs and potential hazards. The aim of our study was to investigate the ability of MBG for the evaluation of functional significance in intermediate coronary lesions during pharmacologic hyperaemia. Fifty-six patients who underwent routine cardiac catheterisation for known or suspected coronary artery disease (CAD) and clinically indicated FFR measures in at least one coronary vessel were analysed. MBGreserve was assessed at baseline and during pharmacologic hyperaemia. Video densitometric parameters were then calculated by the ratio of maximal density (Gmax) and the time to reach maximum density (Tmax). Gmax/Tmax during hyperaemia divided by Gmax/Tmax at baseline provided the MBGreserve. A significant association was observed between MBGreserve and FFR. A cut-off value of MBGreserve=2.1 demonstrated sensitivity of 80% and specificity of 96% for the prediction of abnormal FFR of ≤0.8. MBGreserve increased in coronary territories that underwent PCI, reaching similarly high values compared to those observed in FFR-negative lesions. Quantitative MBGreserve is closely related to FFR measures and may obviate the need for pressure wire measurements in the interests of patient safety, time and costs.