TAV-in-TAV shows lower mean transvalvular gradients than TAV-in-SAV in aortic stenosis reinterventionsTAV-in-TAV shows lower pressure gradients in aortic stenosis patients

Frontiers in Medicine Published September 18, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway

Note that TAV-in-TAV shows lower transvalvular gradients but no significant mortality difference compared to TAV-in-SAV.

This meta-analysis synthesized observational data from 705 patients in extracted comparative cohorts to compare TAV-in-TAV and TAV-in-SAV for patients requiring reintervention for failed bioprostheses. The analysis focused on 30-day mortality, 1-year mortality, transvalvular gradients, and permanent pacemaker (PPM) implantation rates.

Key findings indicate no statistically significant difference in 30-day mortality (OR 0.71; 95% CI 0.25 to 2.00) or 1-year mortality (OR 1.02; 95% CI 0.47 to 2.18) between TAV-in-TAV and TAV-in-SAV. However, TAV-in-TAV was associated with lower mean transvalvular gradients at 30 days (MD -2.71 mmHg; 95% CI -4.07 to -1.34). Regarding permanent pacemaker implantation, there was a non-significant trend toward higher rates in the TAV-in-TAV group (OR 1.85; 95% CI 0.94 to 3.65).

The authors note that the evidence is limited by the observational nature of the source studies and the small number of full-text studies contributing to the primary quantitative analyses. Consequently, the findings are considered hypothesis-generating. Clinically, while TAV-in-TAV shows a consistent early hemodynamic signal with lower gradients, mortality and pacemaker rates do not differ significantly from TAV-in-SAV in this analysis.

How this fits prior evidence

This meta-analysis addresses a gap in comparing specific reintervention techniques for failed bioprostheses in aortic stenosis. While previous coverage noted that SAPIEN 3 TAVR results are comparable to SAVR across different annulus sizes, this study specifically compares TAV-in-TAV to TAV-in-SAV. It confirms that while TAV-in-TAV provides a favorable hemodynamic signal with lower gradients, it does not currently show a statistically significant difference in mortality compared to TAV-in-SAV.

When a heart valve replacement fails, doctors must decide on the best way to fix it. This study looked at two common methods: TAV-in-TAV, where a new valve is placed inside a previously failed transcatheter valve, and TAV-in-SAV, where it is placed inside a failed surgical valve. The goal was to see if one method performed better than the other for patients with aortic stenosis.

The analysis of 705 patients found that TAV-in-TAV resulted in lower mean transvalvular gradients at 30 days compared to TAV-in-SAV. A gradient is a measure of the pressure difference across the valve. While TAV-in-TAV showed this better flow signal, the researchers found no significant difference in 30-day or 1-year mortality rates between the two groups.

There was a slight trend toward more patients needing a new permanent pacemaker with the TAV-in-TAV method, but this was not statistically significant. Because this study relied on limited observational data from only two full-text studies, the results are currently used to generate new ideas rather than provide a definitive rule for treatment.

What this means for you:

TAV-in-TAV shows better blood flow signals, but mortality rates are similar to TAV-in-SAV.

Common questions

What is the difference between TAV-in-TAV and TAV-in-SAV?

Both are ways to replace a failed heart valve. TAV-in-TAV means placing a new transcatheter valve inside a previously failed transcatheter valve. TAV-in-SAV means placing a new transcatheter valve inside a failed surgical valve. This study compared the two to see which had better outcomes for patients with aortic stenosis.

Is one procedure safer or more effective for mortality?

The study found no statistically significant difference in 30-day or 1-year mortality rates between TAV-in-TAV and TAV-in-SAV. While TAV-in-TAV showed lower mean transvalvular gradients at 30 days, the survival rates remained similar for both groups of patients.

Does TAV-in-TAV require more pacemakers?

There was a non-significant trend toward higher rates of new permanent pacemaker implantation in the TAV-in-TAV group. However, because the result was not statistically significant, it does not confirm that one method requires more pacemakers than the other.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedSep 2026

View Original Abstract ↓

BackgroundWith the expanding use of transcatheter aortic valve replacement (TAVR) in younger patients, the need for reintervention on failed bioprostheses is rising. Comparative evidence between redo TAVR for failed transcatheter valves (TAV-in-TAV) and TAVR for failed surgical valves (TAV-in-SAV) is limited.ObjectiveTo systematically review and meta-analyse the clinical, haemodynamic, and safety outcomes of TAV-in-TAV versus TAV-in-SAV.MethodsPubMed, Scopus, Web of Science, Cochrane CENTRAL, and Embase were searched from inception to April 2026. Studies directly comparing TAV-in-TAV with TAV-in-SAV and reporting original data with ≥10 patients per group were included. Risk of bias was assessed using ROBINS-I and the Newcastle-Ottawa Scale. Random-effects meta-analyses were performed for 30-day mortality, 1-year mortality, mean transvalvular gradient at 30 days, and new permanent pacemaker (PPM) implantation.ResultsFour observational studies, including 705 patients in the extracted comparative cohorts, met the inclusion criteria. Two full-text studies contributed to the primary quantitative analyses. TAV-in-TAV was not associated with a statistically significant difference in 30-day mortality compared with TAV-in-SAV (OR 0.71, 95% CI 0.25–2.00), nor in 1-year mortality (OR 1.02, 95% CI 0.47–2.18). TAV-in-TAV was associated with lower mean transvalvular gradients at 30 days (MD −2.71 mmHg, 95% CI −4.07 to −1.34). A non-significant trend toward higher new permanent pacemaker implantation was observed after TAV-in-TAV (OR 1.85, 95% CI 0.94–3.65).ConclusionCurrent comparative evidence between TAV-in-TAV and TAV-in-SAV remains limited and observational. No definitive mortality difference was identified, but clinically meaningful benefit or harm cannot be excluded. TAV-in-TAV shows a consistent early haemodynamic signal with lower gradients, while the possible increase in pacemaker implantation remains exploratory. These findings should be considered hypothesis-generating and require confirmation in larger prospective studies with longer follow-up.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420261369410, PROSPERO CRD420261369410.

TAV-in-TAV shows lower mean transvalvular gradients than TAV-in-SAV in aortic stenosis reinterventionsTAV-in-TAV shows lower pressure gradients in aortic stenosis patients

How this fits prior evidence

Common questions

Study Details

Dual antiplatelet therapy reduces all-cause death but not MACE or myocardial infarction in MINOCA

Dual antiplatelet therapy shows survival benefits for MINOCA patients

Clinical research that matters. Delivered to your inbox.

TAV-in-TAV shows lower mean transvalvular gradients than TAV-in-SAV in aortic stenosis reinterventionsTAV-in-TAV shows lower pressure gradients in aortic stenosis patients

How this fits prior evidence

Common questions

More on Aortic Stenosis

Study Details

Dual antiplatelet therapy reduces all-cause death but not MACE or myocardial infarction in MINOCA

Dual antiplatelet therapy shows survival benefits for MINOCA patients

Clinical research that matters. Delivered to your inbox.

Related in Cardiology

From Other Specialties