Regression of Paravalvular Aortic Regurgitation and Remodeling of Self-Expanding Transcatheter Aortic Valve: An Observation From the CoreValve U.S. Pivotal Trial.

OBJECTIVES: The aim of this study was to describe the natural history and clinical importance of paravalvular aortic regurgitation (PVAR) after CoreValve transcatheter aortic valve replacement (TAVR) and to relate these findings to the structural and hemodynamic changes documented by serial echocardiographic analysis.

BACKGROUND: PVAR after TAVR with the self-expanding CoreValve bioprosthesis has been shown to regress over time, but the time course and the mechanism of PVAR regression has not been completely characterized.

METHODS: Patients with severe aortic stenosis who underwent CoreValve TAVR and followed up to 1 year in the multicenter CoreValve U.S. Pivotal Trial (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement) were studied. Serial echocardiography studies were analyzed by an echocardiographic core laboratory. Annular sizing ratio was calculated from computed tomography measurements. Paired, as well as total, data were compared.

RESULTS: The CoreValve was implanted in 634 patients with a mean age of 82.7 ± 8.4 years. After a marked improvement noted at discharge, aortic valve velocity, mean gradient, and effective orifice area further improved significantly at 1 month (2.08 ± 0.45 m/s vs. 1.99 ± 0.46 m/s, p < 0.0001, 9.7 ± 4.4 mm Hg vs. 8.9 ± 4.6 mm Hg, p < 0.0001, and 1.78 ± 0.51 cm(2) vs. 1.85 ± 0.58 cm(2), p = 0.03, respectively). The improvement was sustained through 1 year. PVAR was moderate or severe in 9.9%, and of 36 patients with moderate PVAR at discharge and paired data, 30 (83%) improved at least 1 grade of regurgitation at 1 year. Annular sizing ratio was significantly associated with the degree of PVAR.

CONCLUSIONS: There was further improvement in aortic prosthetic valve hemodynamics and regression of PVAR up to 1 year compared with discharge after TAVR with CoreValve. These changes are possibly due to remodeling and outward expansion of the self-expandable CoreValve with nitinol frame. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement [Medtronic CoreValve U.S. Pivotal Trial]; NCT01240902).