Abstract Body (Do not enter title and authors here): Background: Intracoronary measurement of fractional flow reserve (FFR) has demonstrated higher sensitivity and better negative predicative value in evaluation of coronary artery disease than visual/angiographic only evaluation. Nonetheless, there is profound lack of evidence in the available literature that discusses the rate of complications when utilizing FFR versus standard angiography.

Research question: Does FFR carry higher or lower risk of procedural complications when compared with standard angiography?

Aim: Compare the risk of complications encountered in FFR guidance in comparison to angiography only.

Methods: The following databases were searched; PubMed, SCOPUS, CENTRAL, Web of Science. The following keywords were used; ((Fractional flow reserve OR FFR) AND (Adverse effect OR Complication)). The studies were included if they compared Angiography-guided Percutaneous Coronary Intervention (PCI) and Fractional Flow Reserve (FFR)-guided PCI in terms of mortality or Major Adverse Cardiac Events (MACE). Case reports and series, animal studies, reviews and non-English articles were excluded from this study. The exposure of interest was FFR-guided PCI whereas the outcomes of interest were MACE and mortality.

Results: A total of 1,822 articles were identified. After removing duplicates, initial screening, and secondary screening, 15 articles were included and the total number of included patients was 421,291. The percentage of patients who underwent FFR guidance was 3.5% whereas the rest underwent angiography only. Male predominance was noted in both, FFR and angiography. The mean age of the patients who underwent FFR and angiography was 64.9 ± 9.1 and 65.2 ± 9.3 years, respectively. The model that compared between angiography only and FFR in MACE (14 studies) showed that FFR was significantly associated with lower risk of MACE compared to angiography (RR=0.62, 95%CI:0.48-0.81); this model also showed significant heterogeneity (P-value<0.001, I2=80%). 14 studies were included in the model comparing between angiography and FFR in terms of death which showed that FFR was significantly associated with a lower risk of death in comparison with angiography only (RR=0.60, 95%CI:0.41-0.89); this model also showed significant heterogeneity (P-value<0.001, I2=72%).

Conclusion: The currently available literature demonstrates that, despite the significant heterogenicity, MACE and mortality are substantially lower in FFR in comparison to angiography only guidance.