282 Park SH & Koo BK. Clinical application of FFR in bifurcation lesions after angioplasty may not reflect the functional and clinical outcomes during follow-up due to influence of thrombus or edema related to the intervention.[43] Two studies evaluated the changes of SB FFR between immediate post-procedure and follow-up.[34,38] There was no significant interval change of SB FFR between post-angioplasty and follow-up in both studies (0.86 ± 0.05 to 0.84 ± 0.01, P = 0.4 by Koo et al.[34] and 0.92 to 0.91, P = 0.8 by Kumsars et al.[38]). Therefore, immediate post-procedural SB FFR appears to be a useful index that can predict the functional patency of these lesions during follow-up. However, it should be noted that the functional and angiographic late loss depends on the degree of injury sustained during the procedure. In cases of severe SB dissection or slow flow after SB balloon angioplasty, SB stenting or additional SB balloon angioplasty should be considered without measuring SB FFR. 6 FFR after SB stenting Previous multicenter registry data suggested that FFR values after bare metal stent implantation was a strong independent predictor of outcomes, and patients with an FFR > 0.90 after stenting had very low event rates.[44] Physiologic evaluation using FFR can give additional information on the appropriateness of complex intervention for bifurcation lesions. In a study by Lee et al.,[45] SB FFR was measured before and after kissing balloon dilatation in patients treated with the crush technique, and kissing balloon dilatation increased FFR from 0.94 ± 0.04 to 0.97 ± 0.03 (P = 0.011). Another study reported that double kissing crush stenting was asso- ciated with higher SB FFR as compared with the provisional strategy in true bifurcation lesions (0.94 ± 0.3 in crush vs. 0.90 ± 0.08 in provisional group, P = 0.028).[46] These results suggest that SB FFR can be helpful to assess the procedural success after SB stenting. However, it should be noted that high FFR does not always guarantee excellent outcomes of complex intervention for bifurcation lesions. In a study by Lee et al.,[45] SB FFR was already 0.94 ± 0.4 even before the kissing balloon dilatation. Therefore, SB FFR has a limitation in the prediction of long-term procedural outcomes after SB stent implantation. 7 FFR in left main bifurcation lesion In general, same tips and tricks for non-left main bifur- cation lesions can be applied to the left main bifurcation lesions. However, the application of FFR to the left main bifurcation lesions is more complicated as most left main bifurcation lesions are associated with other lesions. 8 Conclusions Current angiographic evaluation frequently overestimates the functional severity of bifurcation lesions and can lead to unnecessary complex intervention. Therefore, a functional assessment by FFR in conjunction with an anatomical evaluation can be a useful approach to guide appropriate interventional treatment for bifurcation lesions. However, adequate knowledge of coronary physiology and the pitfalls of FFR is required to optimize the clinical utility of FFR in complex bifurcation lesion procedures. References 1 2 3 4 5 6 7 8 9 10 11 Latib A, Colombo A. Bifurcation disease: What do we know, what should we do? J Am Coll Cardiol Intv 2008; 1: 218–226. Iakovou I, Ge L, Colombo A. Contemporary stent treatment of coronary bifurcations. J Am Coll Cardiol 2005; 46: 1446–1455. Yamashita T, Nishida T, Adamian MG, et al. 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