@article {GalaskoA10, author = {Gavin Galasko}, title = {20 A comparison of two iFR methods to predict FFR (fractional flow reserve) - the blackpool coronary iFR study (BCIS)}, volume = {102}, number = {Suppl 4}, pages = {A10--A10}, year = {2016}, doi = {10.1136/heartjnl-2016-309588.20}, publisher = {BMJ Publishing Group Ltd}, abstract = {Background The iFR (instantaneous free-wave ratio) is a new adenosine-independent measure of ischaemia possibly equivalent to FFR. 2 cut-offs have been mooted: A) iFR <=0.89 abnormal and B) iFR \<0.86 abnormal, iFR \>0.93 normal and iFR 0.86{\textendash}0.93 a grey-zone where FFR should be measured (hybrid approach). No study has prospectively assessed A vs B.Methods Consecutive patients undergoing FFR had iFR measured first with A vs B compared in predicting FFR.Results 55 consecutive patients were assessed: 34 men, mean age 63. 105 coronary arteries were assessed: mean FFR 0.84; 36 (34\%) FFR <=0.8; mean iFR 0.92; 34 (32\%) iFR <=0.89; 12 (11\%) had iFR \<0.86, 50 (48\%) iFR 0.86{\textendash}0.93 and 43 (41\%) iFR \>0.93. The correlation between iFR and FFR gave R2 0.64. The overall agreement between iFR and FFR was 79\% using method A vs 98\% using the hybrid/grey-zone approach. The sensitivity, specificity, PPV and NPV were: 71\% vs 100\%; 83\% vs 97\%; 67\% vs 94\% and 86\% vs 100\%, respectively, with the hybrid approach superior for each value. Of the 50 grey zone cases, 22 (44\%) had FFR <=0.8 with method A only 60\% accurate in predicting FFR. Outside the grey zone, method A was 96\% accurate in predicting FFR. iFR was highly reproducible with 95\% limits of agreement +0.01{\textendash}0.015.Conclusion The iFR is reproducible with modest correlation to FFR. Outside the grey zone, iFR \<0.86 as abnormal and \>0.93 as normal accurately predict FFR. Within the grey zone iFR 0.86{\textendash}0.93 adenosine should be given and FFR measured. Using this approach 52\% of cases would not require adenosine, with 98\% accuracy.}, issn = {1355-6037}, URL = {https://heart.bmj.com/content/102/Suppl_4/A10.3}, eprint = {https://heart.bmj.com/content/102/Suppl_4/A10.3.full.pdf}, journal = {Heart} }