Paravalvular Leak After Transcatheter Aortic Valve Implantation: Haemodynamic Consequences, Clinical Impact, and Contemporary Assessment.

Paravalvular leak (PVL) remains an important limitation of transcatheter aortic valve implantation (TAVI), despite major advances in prosthesis design, imaging guidance, and implantation technique. Although the incidence of moderate and severe PVL has substantially declined with newer-generation valves, mild PVL continues to be frequently observed in contemporary practice and is increasingly recognised as clinically relevant. Multiple studies have demonstrated an association between even mild PVL and adverse outcomes, particularly heart failure (HF) hospitalisation, suggesting that conventional grading systems may underestimate its true haemodynamic burden. Beyond simple regurgitant volume, PVL is characterised by eccentric high-velocity flow, turbulence, impaired pressure recovery, and reduced haemodynamic efficiency. These effects may be particularly important in vulnerable phenotypes such as patients with heart failure with preserved ejection fraction (HFpEF), concentric left ventricular hypertrophy, or low-flow states, in whom small regurgitant volumes can result in disproportionate increases in filling pressures and symptomatic deterioration. This review summarises contemporary evidence regarding the prevalence, diagnosis, haemodynamic impact, and clinical consequences of PVL after TAVI. Differences across valve platforms, predictors of PVL, and current management strategies are also discussed. Particular emphasis is placed on the limitations of pressure-based assessment and the need for a patient-specific, flow-oriented approach aligned with contemporary endpoint definitions such as those proposed by VARC-3.