Catherine Liontou of the team of Dr Javier Escaned published very recently in EuroIntervention a study on the functional assessment of in-stent restenosis (ISR) with QFR. This was a multi-center, international, retrospective, blinded study, enrolling patients from 3 hospitals in three countries (Hospital Clínico San Carlos, Spain, Toda Chuo General Hospital, Japan and Sejong General Hospital, South Korea). The study population consisted of a group of ISR patients in whom FFR was used to guide coronary revascularization in clinical practice. QFR analysis was performed in 78 vessels (73 patients) with ISR, all investigated with FFR. Mean difference between FFR and QFR was only 0.01 ± 0.09. Classification agreement between FFR and QFR was high, i.e. 83%. The area under the ROC curve (AUC) demonstrated high diagnostic performance of QFR regarding its ability to establish ISR relevance, taking FFR as reference. Very importantly, 45% of the ISR cases deemed significant by angiographic criteria, were judged as functionally non-significant both by QFR and FFR, showing that due to its high negative predictive value, QFR can lead to safe deferral of revascularization of significant proportion of ISR lesions.
For further read: EuroIntervention. 2019 Jul 30. pii: EIJ-D-18-00955. doi: 10.4244/EIJ-D-18-00955