Background: Optimal transcatheter heart valve (THV) sizing is crucial to optimize procedural outcomes. Larger THV oversizing is shown to decrease paravalvular leakage post transcatheter aortic valve replacement but its role in Valve in Valve implantation (ViV) is not well established.
Methods: For each surgical type and label size, the two commonly used THV sizes, a given THV “standard” vs. a size larger “oversized” were compared among patients undergoing aortic ViV within VIVID Registry. The degree of THV perimeter oversizing was calculated as: (THV nominal size – surgical valve true ID)/true ID x 100.
Results: A total of 595 patients (359 for standard size and 236 for oversized group) were included in the analysis. Baseline clinical, hemodynamic and surgical valve parameters were similar in these two groups. Both groups used similar THV devices in each matched comparison. The oversized group received a larger THV (25.5± 1.4 mm vs. 23.3 ± 1.0 mm, p<0.001) with a greater degree of THV oversizing (31% ± 10.6 vs. 20% ± 9.5, p=<0.001) compared to the standard cohort. Post-implantation, the oversized group achieved a larger EOA (1.54±0.4cm2 vs. 1.37± 0.5cm2, p<0.001) and lower MG (15.1±8.1mmHg vs. 17.4±8.5mmHg, p=0.002) in comparison to the standard cohort. The oversized group however, had a higher rate of moderate to severe AI (6.9% vs. 2.7%, p=0.001) and second THV requirement (5.5%vs. 2.2%, p=0.04). THV mal-positioning, coronary obstruction and postoperative pacemaker requirement were not significantly different. THV oversizing was an independent predictor of the observed hemodynamic differences: (β 0.01, p = 0.001), (β 0.23, p =<0.001), Odds ratio 1.06 (1.005 - 1.113), p = 0.031 for EOA, MG and AI respectively.
Conclusion: The strategy of highly oversized THV selection for ViV implantation was associated with favorable post-implant EOA and gradient but a higher risk of aortic insufficiency and THV re-intervention. Further exploration within various THV and surgical valve types at different degree of THV oversizing is planned.