ABC | Volume 111, Nº4, Octuber 2018

Original Article Martins ACS Fractional flow reserve-guided strategy Arq Bras Cardiol. 2018; 111(4):542-550 1. De Bruyne B, Sarma J. Fractional flow reserve: a review: invasive imaging. Heart. 2008;94(7):949-59. 2. Pijls NH, van Schaardenburgh P, Manoharan G, Boersma E, Bech JW, van’t Veer M, et al. Percutaneous coronary intervention of functionally nonsignifica ntstenosis:5-yearfollow-upoftheDEFERStudy.JAmCollCardiol. 2007;49(21):2105-11. 3. Zimmermann FM, Ferrara A, Johnson NP, van Nunen LX, Escaned J, Albertsson P, et al. Deferral vs. performance of percutaneous coronary intervention of functionally non-significant coronary stenosis: 15-year follow-up of the DEFER trial. Eur Heart J. 2015;36(45):3182-8. 4. Tamita K, Akasaka T, Takagi T, Yamamuro A, Yamabe K, Katayama M, et al. Effects of microvascular dysfunction on myocardial fractional flow reserve after percutaneous coronary intervention in patients with acutemyocardial infarction. Catheter Cardiovasc Interv. 2002;57(4):452-9. 5. Tani S, Watanabe I, Kobari C, Matsumoto M, Miyazawa T, Iwamoto Y, et al. Mismatch between results of myocardial fractional flow reserve measurements and myocardial perfusion SPECT for identification of the severity of ischaemia. Jpn Heart J. 2004;45(5):867-72. 6. Yong AS, FearonWF. Coronary microvascular dysfunction after ST-segment elevation myocardial infarction: local or global phenomenon? Circ Cardiovasc Interv. 2013;6(3):201-3. 7. Kumar A, Cannon CP. Acute coronary syndromes: diagnosis and management, Part I. Mayo Clin Proc. 2009;84(10):917-38. 8. Fischer JJ, Wang XQ, Samady H, Sarembock IJ, Powers ER, Gimple LW, et al. Outcome of patients with acute coronary syndromes and moderate coronary lesions undergoing deferral of revascularisation based on fractional flow reserve assessment. Catheter Cardiovasc Interv. 2006;68(4):544-8. 9. Potvin JM, Rodes-Cabau J, Bertrand OF, Gleeton O, Nguyen CN, Barbeau G, et al. 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Coronary angioplasty in patients with unstable angina: clinical, electrocardiographic and angiographic predictors of in-hospital outcome. R.OS.A.I. Study Group. Ital Heart J. 2000;1(8):555-61. 13. Layland J, Carrick D, McEntegart M, Ahmed N, Payne A, McClure J, et al. Vasodilatory capacity of the coronary microcirculation is preserved in selected patients with non-ST-segment-elevation myocardial infarction. Catheter Cardiovasc Interv. 2013;6(3):231-6. 14. Henningam B, Layland J, Fearon WF, Oldroyd KG. Fractional flow reserve and the index of microvascular resistance in patients with acute coronary syndromes. EuroIntervention. 2014 Aug;10 Suppl T:T55-63. References Besides that, due to the great heterogeneity of inclusion criteria, follow-up period and the vessel assessed by FFR, results and conclusion of the current study should be the interpreted with caution. Limitations The conclusions drawn from this meta-analysis are subject to the limitations and differences of the original studies included in the analysis. First, our meta-analysis included both randomized clinical trials and (mostly) observational studies. The conclusions of this study may be somewhat limited due to biases inherent in the observational studies, including design, selection, and treatment bias. Another possible limitation is the potential publication bias because the results only included short-term mortality. Conclusion The prognostic value of FFR in ACS setting is not as good as in stable patients. More homogeneous studies with larger populations of patients are necessary to reach definitive and robust conclusions. Careful definition and interpretation of the clinical results is important when analysis of FFR is not performed in patient-level but in vessel-level only. Acknowledgements We thank theCIDMA - Center for Research andDevelopment in Mathematics and Applications of the University of Aveiro for the statistical analysis, and the Portuguese Foundation for Science and Technology (FCT - Fundação para a Ciência e a Tecnologia) (project UID/MAT/04106/2013). Author contributions Conception and design of the research, Acquisition of data, Analysis and interpretation of the data and Writing of the manuscript: Martins JL; Statistical analysis: Martins JL, Afreixo V; Critical revision of the manuscript for intellectual content: Martins JL, Afreixo V, Santos J, Gonçalves L. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This article does not contain any studies with human participants or animals performed by any of the authors. 548