Prehabilitation Before Cardiac Surgery and Structural Heart Interventions: An Umbrella Review of Pooled Evidence

Background: Prehabilitation aims to optimise patients before cardiac procedures through interventions including exercise training, respiratory conditioning, nutritional support, psychological preparation and multimodal lifestyle programmes. Evidence from systematic reviews and meta-analyses is increasing but remains heterogeneous due to variation in intervention design, patient populations and overlap of primary studies. Methods: We conducted an umbrella review of 17 systematic reviews and meta-analyses evaluating prehabilitation prior to cardiac surgery and structural heart interventions in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodological quality of included reviews was assessed using A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2). Outcomes of interest were postoperative pneumonia, hospital length of stay (LOS), and mortality. Results: Across pooled analyses, the most consistent finding was a reduction in postoperative pneumonia, particularly in studies incorporating inspiratory muscle training (IMT), with relative risk reductions of approximately 55-62%, corresponding to a modest absolute risk reduction. Reductions in hospital LOS were also reported, although effect sizes were smaller and more variable. In contrast, no consistent reduction in short-term mortality was demonstrated, likely reflecting low event rates. The evidence base was limited by substantial overlap between reviews and predominantly low or critically low methodological quality. Conclusions: Prehabilitation, particularly when incorporating IMT, is consistently associated with a reduction in postoperative pneumonia and may contribute to modest reductions in hospital LOS. However, the evidence base is constrained by heterogeneity, study overlap and low methodological quality. Further high-quality, adequately powered randomised trials are required to define the role of prehabilitation in contemporary cardiac surgical and structural intervention practice.