To Cath or Not to Cath, That Is the Question? Towards a Minimally Invasive Pre-Glenn Assessment

Background: Routine cardiac catheterization has traditionally been considered mandatory prior to the bidirectional Glenn procedure in patients with single-ventricle physiology, aiming to assess pulmonary artery anatomy, pulmonary pressures, and ventricular filling. However, invasive assessment carries procedural risk and cumulative radiation exposure, while advances in non-invasive imaging have challenged this paradigm. Main Body: This review synthesizes historical practice, contemporary evidence, and evolving guideline recommendations regarding pre-Glenn assessment. Landmark randomized data, most notably from Brown et al., demonstrated that cardiac magnetic resonance provides equivalent surgical decision-making and early outcomes compared with routine catheterization, while significantly reducing adverse events, hospital stay, and cost. Subsequent institutional experiences and international guidelines (2020–2023) have reinforced a selective approach, favoring non-invasive imaging—particularly cardiac magnetic resonance —unless an intervention is anticipated or non-invasive findings are equivocal. Furthermore, we propose a phenotype-guided strategy for a subset of patients with favorable ventricular morphology and shunt-dependent pulmonary blood flow, in whom targeted echocardiography with adjunctive computed tomography angiography may suffice. Conclusion: Accumulating evidence supports a shift from universal invasive assessment toward individualized, risk-stratified pre-Glenn evaluation. A selective imaging-driven strategy may safely reduce procedural burden while preserving diagnostic accuracy in carefully chosen patients.