Comparison of SYNTAX scores between coronary CT angiography and invasive coronary angiography: a systematic review...

Accurate assessment of coronary lesion complexity is essential for guiding revascularization strategies in patients with coronary artery disease. The SYNTAX score, originally derived from invasive coronary angiography (ICA), plays a key role in clinical decision-making. With advancements in cardiac computed tomography angiography (CCTA), its potential as a non-invasive tool for SYNTAX scoring has gained interest, but discrepancies between modalities remain uncertain. To systematically compare SYNTAX scores obtained by CCTA versus ICA and evaluate their concordance, with implications for clinical decision-making. We conducted a systematic review and meta-analysis of studies published between 2013 and 2024 comparing SYNTAX scores derived from CCTA and ICA in the same adult populations. Databases including PubMed, Embase, Scopus, Web of Science, and Cochrane Library were searched through January 2025. The primary outcome was the pooled standardized mean difference (Hedges' g) in SYNTAX scores between modalities. Risk of bias was assessed using QUADAS-2, and meta-regression explored potential sources of heterogeneity. Thirteen studies with a total of over 1,800 patients met inclusion criteria. The pooled analysis demonstrated a statistically significant underestimation of SYNTAX scores by CCTA compared to ICA (Hedges' g = - 0.121; 95% CI: -0.185 to - 0.056; p < 0.01). Heterogeneity was moderate (I² = 30.7%) after exclusion of one outlier. Meta-regression revealed no significant impact of publication year, scanner generation, or sample size on effect size. Several studies highlighted meaningful discrepancies in SYNTAX classification near critical decision thresholds (22 and 32). Funnel plot symmetry and Q-Q plot normality suggested minimal publication bias. CCTA systematically underestimates SYNTAX scores compared to ICA, which may impact treatment decisions in patients with complex coronary artery disease. While CCTA offers a promising non-invasive alternative, clinicians should interpret CCTA-derived SYNTAX scores with caution-particularly in borderline cases where therapeutic strategies may differ. Further standardization of scoring protocols and incorporation of functional imaging tools such as CT-FFR are warranted.