Incidence, Predictors, and Outcomes of Aortic Regurgitation After Transcatheter Aortic Valve Replacement: Meta-Analysis and Systematic Review of Literature
What is the clinical significance of aortic regurgitation (AR) following transcatheter aortic valve replacement (TAVR)?
This meta-analysis and systematic review evaluated 45 studies, including 12,926 patients who underwent TAVR. Studies were included if they reported results on post-TAVR AR severity, predictors of AR, or mortality based on AR severity. Exclusion criteria included duplicate publications, lack of data on post-TAVR AR severity, inability to measure outcomes, valve-in-valve procedures, or use of valves other than the CoreValve (Medtronic) or Edwards valve (Edwards Lifesciences). Primary endpoints of the study included: overall incidence of ≥moderate AR post-TAVR, effect of post-TAVR AR on 30-day and long-term mortality, and predictors of AR.
The study included 12,926 patients (CoreValve in 40.7%, Edwards valve in 56.3%). Moderate or severe AR was present in 11.7% of patients, and trivial or mild AR was observed in 45.9% of individuals. In subgroup analyses, moderate or severe AR was noted in 16.0% of patients after CoreValve implantation versus 9.1% of individuals following Edwards valve implantation (p = 0.005). Variables potentially associated with post-TAVR AR included valve undersizing, aortic valve calcification, and implantation depth. Patients with moderate or severe AR following TAVR had increased 30-day mortality (odds ratio, 3.0; 95% confidence interval [CI], 1.7-5.0; p = 0.001), and increased 1-year mortality (hazard ratio, 2.3, 95% CI, 1.8-2.8; p = 0.001). Mild AR following TAVR was associated with increased mortality (hazard ratio, 1.8; 95% CI, 1.01-3.3; p = 0.048), although on sensitivity analyses, this was no longer statistically significant.
The authors concluded that moderate or severe AR is common following TAVR, and is associated with increased mortality. The presence of mild AR after TAVR may be associated with increased mortality.
AR is the most frequent complication following TAVR, with the majority of patients having some AR following this procedure, and 12% of individuals having moderate or severe AR in the present meta-analysis. While moderate or severe AR has been demonstrated to be associated with increased mortality in multiple studies, outcomes in patients with mild AR have been less clear, although data suggest a potential risk of increased mortality. These results may be confounded by the difficulty in accurately quantifying the severity of AR following TAVR, as paravalvular AR in TAVR patients is frequently comprised of multiple eccentric jets, and accurate and reproducible assessment can be challenging due to the lack of a comprehensive standardized approach to grading post-TAVR AR. This study reported an increased prevalence of moderate or severe AR in patients treated with the CoreValve as compared with the Edwards valve, but the appearance and pattern of paravalvular AR differs between these valves, and standardized AR grading is needed to verify these findings. Further, while it is not surprising that significant acute AR can have adverse clinical consequences, it is not immediately clear why mild AR may also have this result, and there is a possibility that at least some of the observed risk associated with AR is due to this representing a surrogate for other risk factors. Given the rapidly expanding utilization of TAVR, there is a strong need for improved identification of patients at risk for AR, improvement in techniques and devices to reduce AR, and standardization of grading AR.
Keywords: Prevalence, Incidence, Heart Valve Prosthesis, Cardiology, Calcinosis, Risk Factors, Heart Valve Prosthesis Implantation, Angioplasty
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