Comparison of Transvalvular Aortic Mean Gradients Obtained by Intraprocedural Echocardiography and Invasive Measurement in Balloon and Self‐Expanding Transcatheter Valves

Abstract

Background Concerns about discordance between echocardiographic and invasive mean gradients after transcatheter aortic valve replacement (TAVR) with balloon‐expandable valves (BEVs) versus self‐expanding valves (SEVs) exist. Methods and Results In a multicenter study, direct‐invasive and echocardiography‐derived transvalvular mean gradients obtained before and after TAVR were compared as well as post‐TAVR and discharge echocardiographic mean gradients in BEVs versus SEVs in 808 patients. Pre‐TAVR, there was good correlation (R=0.614; P<0.0001) between direct‐invasive and echocardiography‐derived mean gradients and weak correlation (R=0.138; P<0.0001) post‐TAVR. Compared with post‐TAVR echocardiographic mean gradients, both valves exhibit lower invasive and higher discharge echocardiographic mean gradients. Despite similar invasive mean gradients, a small BEV exhibits higher post‐TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post‐TAVR and discharge mean gradients. An ejection fraction <50% (P=0.028) and higher Society of Thoracic Surgeons predicted risk of mortality score (P=0.007), but not invasive or echocardiographic mean gradient ≥10 mm Hg (P=0.378 and P=0.341, respectively), nor discharge echocardiographic mean gradient ≥20 mm Hg (P=0.393), were associated with increased 2‐year mortality. Conclusions Invasively measured and echocardiography‐derived transvalvular mean gradients correlate well in aortic stenosis but weakly post‐TAVR. Post‐TAVR, echocardiography overestimates transvalvular mean gradients compared with invasive measurements, and poor correlation suggests these modalities cannot be used interchangeably. Moreover, echocardiographic mean gradients are higher on discharge than post‐TAVR in all valves. Despite similar invasive mean gradients, a small BEV exhibits higher post‐TAVR and discharge echocardiographic mean gradients than a large BEV, whereas small and large SEVs exhibit similar post‐TAVR and discharge mean gradients. Immediately post‐TAVR, elevated echocardiographic‐derived mean gradients should be assessed with caution and compared with direct‐invasive mean gradients. A low ejection fraction and higher Society of Thoracic Surgeons score, but not elevated mean gradients, are associated with increased 2‐year mortality.

Keywords

• Bernoulli equation
• echocardiographic and invasive discordance
• pressure recovery
• transcatheter aortic valve replacement