Abstract
Background:Intraoperative graft assessment during coronary artery bypass grafting (CABG) aims to identify technical anastomotic defects before chest closure. Transit-time flow measurement (TTFM) and indocyanine green (ICG) fluorescence imaging represent complementary intraoperative assessment modalities, yet their comparative diagnostic performance against angiographic reference standards remains incompletely defined. Methods: PubMed, Scopus, Web of Science Core Collection, and CENTRAL were searched from January 2000 to February 2026 using terms for CABG, ICG, and TTFM; duplicate screening yielded κ = 0.86–0.91. Eligible studies evaluated ICG and/or TTFM against invasive coronary angiography or computed tomography coronary angiography. Methodological quality was appraised using QUADAS-2 for diagnostic cohorts and the Newcastle-Ottawa Scale (NOS) for clinical-utility cohorts. Because only three directly comparable cohorts provided sufficiently reliable paired 2×2 data, formal bivariate random-effects meta-analysis was not performed. Verified 2×2 contingency data were summarised descriptively with exact Clopper–Pearson 95% confidence intervals. Clinical-utility evidence was synthesised narratively. Results: Eighteen unique primary clinical studies were included. Three studies (Desai et al., 2006; Yamamoto et al., 2015; Hatada et al., 2011), comprising 293 paired bypass grafts, provided directly comparable quantitative evidence. ICG demonstrated an aggregate descriptive sensitivity of 76.0% (95% CI, 54.9%–90.6%) and specificity of 99.3% (95% CI, 97.3%–99.9%). TTFM/flowmetry demonstrated aggregate sensitivity of 24.0% (95% CI, 9.4%–45.1%) and specificity of 96.3% (95% CI, 93.2%–98.2%). Formal between-modality P values were not calculated. The aggregate flowmetry estimate includes one cohort using experimental FFT-based waveform analysis (Hatada et al., 2011) and should be interpreted with caution. NOS assessment of six Tier 3 clinical-utility studies yielded scores of 5–9/9; no study provided a complete two-arm comparison with non-zero revision events in both arms, precluding pooled effect estimation. Conclusions: ICG fluorescence imaging showed higher descriptive sensitivity than TTFM/flowmetry for detecting structural graft abnormalities. A complementary approach combining quantitative flow assessment with selective fluorescence imaging may be considered in appropriately selected situations. Prospective multicenter studies are required before definitive recommendations can be made.