Utility of the fractional flow reserve in the evaluation of angiographically moderate in-stent restenosis

AIMS: The evaluation of in-stent restenosis (ISR) is usually based on angiographic quantification. This evaluation is sometimes difficult and it has not an accurate clinical correlation. Fractional flow reserve (FFR) measured by intracoronary pressure wire has demonstrated its value in determining the functional repercussion of coronary stenosis. The aim of this study was to evaluate the relation between quantitative angiography-FFR in borderline in-stent restenotic lesions and the accuracy of FFR in deciding the treatment of ISR. METHODS AND RESULTS: Quantitative angiographic values of 65 lesions in 62 patients with angiographically moderate ISR are compared with the FFR value obtained by pressure wire. An FFR value<0.75 was considered significant. Patients with non-revascularized ISR (FFR > or = 0.75) were clinically followed during a year. An FFR value > or = 0.75 was obtained in 41 lesions (63%), 21 of them with stenosis > or = 50%. The co-efficient of correlation between parameters of quantitative angiography and FFR value was <0.5. No events related to the non-treated lesions were observed. CONCLUSIONS: A poor correlation between angiographic quantification and FFR of moderate ISR was found. Conservative management of moderate 40-70% in-stent restenotic lesions with FFR value > or = 0.75 is safe avoiding unnecessary revascularizations based solely on the angiography.