Outcomes With Post-Dilation Following Transcatheter Aortic Valve Replacement in the PARTNER I Trial (Placement of Aortic Transcatheter Valve)
What are the predictors and outcomes of post-dilation (PD) for a balloon-expandable transcatheter aortic valve replacement (TAVR)?
This study evaluated the predictors and outcomes of PD in patients with severe aortic stenosis (AS) treated with a balloon-expandable TAVR device, and includes patients from the PARTNER I trial cohort A (n = 304) and cohort B (n = 194), as well as patients enrolled in the nonrandomized continued access study (n = 1,637). PD was performed at the discretion of the site.
PD was performed in 261/2,123 patients (12%). Risk factors for PD included male gender, large body size, smoking, prior coronary artery bypass grafting, and the use of a 26-mm valve size (p < 0.01 for each). Patients with (vs. without) PD had a larger effective orifice area (1.9 ± 0.5 vs. 1.7 ± 0.5 cm2 at 30 days, p < 0.001), greater paravalvular regurgitation (mild in 49% vs. 37%, ≥ moderate in 12% vs. 8% at discharge, p < 0.001), and less patient-prosthesis mismatch (31% vs. 46% at 30 days, p < 0.001). On multivariable analysis, PD was independently associated with less patient-prosthesis mismatch (p = 0.002). There was no difference for in-hospital mortality among those with versus without PD (3.0% vs. 2.5%, p = 0.62), although there was a trend to increased in-hospital stroke (4.9% vs. 2.9%, p = 0.08). Patients with (vs. without) PD had no difference in composite stroke or death at discharge (5.7% vs. 4.4%, p = 0.37), although there was a significant difference in this endpoint at 1 year (28.2% vs. 23.0%, p = 0.04). On multivariable analyses, PD was not associated with mortality at 1 year (p = 0.46) or composite stroke/mortality at 1 year (p = 0.47), although it was associated with increased risk of acute stroke within 7 days (hazard ratio, 1.90; 95% confidence interval, 1.03-3.50; p = 0.04).
PD for TAVR is associated with reduced patient-prosthesis mismatch and an increased effective orifice area. It is also associated with increased risk of acute stroke within 7 days, although there is no evidence for an increased risk of stroke at later intervals of follow-up. It is not associated with a difference in adjusted mortality.
This study examines the outcomes of PD in TAVR with the SAPIEN balloon-expandable device. PD was not uncommon in this study, and was used in 12% of cases. It is most typically used when there is significant paravalvular regurgitation following initial balloon deployment valve prosthesis. However, as PD was at the discretion of the local TAVR team and paravalvular regurgitation prior to PD was not recorded, the indications for PD in this study are not known. Improved valve sizing with the use of computed tomography may reduce the need for PD, although this was not evaluated. Furthermore, significant variation in the use of PD between sites is likely, and comparisons between sites with frequent and less frequent use of this would be of interest. While there are concerns that PD may be associated with risks such as stroke, it is well known that significant paravalvular regurgitation is associated with increased mortality. Therefore, it can be a challenge in some cases to decide whether to pursue PD or leave residual paravalvular regurgitation, and the present results may help inform these decisions. However, the precise situations in which PD is likely to be helpful are not entirely clear, and future study is needed to rigorously define its appropriate role.
Keywords: Heart Valve Prosthesis, Stroke, Follow-Up Studies, Hospital Mortality, Bioprosthesis, Tomography, Risk Factors, Confidence Intervals, Body Size, Coronary Artery Bypass, Smoking
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