ABC | Volume 111, Nº4, Octuber 2018

Original Article Martins ACS Fractional flow reserve-guided strategy Arq Bras Cardiol. 2018; 111(4):542-550 January 2000 and September 2017. Previous qualitative and systematic reviews, if available, were searched for additional studies. The query terms “Flow Fractional Reserve” OR “Acute Coronary Syndrome” were used in the search. References of the studies identified by the search strategy were reviewed for potentially relevant articles not identified by the above search. No language restrictions were enforced. Study selection The title/abstract of citations were first screened by 2 independent reviewers (JM and VA), and complete manuscripts were retrieved if consideredpotentially relevant. Additional studies were identified by reviewing the bibliographies of included studies and relevant reviews. Disagreements were resolved by consensus. The same reviewers independently appraised identified articles according to the following inclusion criteria: studies that compared clinical outcomes of lesions after PCI deferred based on FFR between ACS patients and non-ACS patients (Figure 1). Endpoints The endpoints studied were: mortality, cardiovascular mortality, myocardial infarction (MI), and target vessel revascularization (TVR) during the follow-up period. TVR of the target vessel was defined as subsequent revascularization of the index vessel by either PCI or bypass grafting. In all trials, in the ACS group, distinction between culprit and non-culprit lesions was based on the operator’s discretion, and hence subjective, similar to clinical practice. Statistical analysis Continuous variables were expressed as means ± standard deviations or median (with interquartile range) values, and categorical variables were described as numbers and percentages. To calculate pooled effect estimates, we used the inverse variance assuming a fixed-effects model and the DerSimonian-Laird method assuming a random‑effects model. 16 Homogeneity among the studies was evaluated using Cochran’s Q test and the I2 statistic (the values of 0.25, 0.50, and 0.75 indicated low, moderate, and high degrees of heterogeneity, respectively). Publication bias was evaluated using funnel plots. We performed a sensitivity analysis to evaluate the impact of each study on the results. MetaXL 2.0 (EpiGear International Pty Ltd, Wilston, Queensland, Australia) was used to calculate the pooled risk difference effect sizes (difference in occurrence risk between revascularization and conservative management groups). Results Study identification The search strategy initially retrieved 129 citations. Of these, 96 articles were excluded after review of the title or abstract. After assessment or the studies for the selection criteria, we excluded an additional 26 studies. A total of 7 studies met criteria for the meta-analysis, involving 5,107 (3,540 non-ACS and 1,567 ACS) patients. Figure 1 – Flowchart of studies included in the meta-analysis. 928 articles searched (published between January 1, 2000 and September, 2017) Duplicate studies removed (n = 3) 129 articles screened 33 full text articles screened 7 articles included Exclusion by title and abstract screening (n = 96) Exclusion by full text screening (n = 26) Exclusion criteria: • Study design – review (n = 20) – editorial (n = 3) – no discrimination in outcomes between ACS vs non-ACS (n = 3) 543