Transcatheter aortic valve replacement (TAVR) in patients with failed transcatheter aortic valves (TAVs) was associated with higher procedural success than TAVR in those with failed surgical aortic valves (SAVs), according to a new registry analysis.
However, the same two propensity-score-matched cohorts had similar procedural safety and mortality rates, while mild aortic regurgitation appeared to be more frequent for TAV-in-TAV patients.
The analysis was based on data from 212 TAV-in-TAV and 595 TAV-in-SAV consecutive procedures from the international 63,876-patient Redo-TAVR registry, assessing procedures in 37 centers between April 2005 and April 2019. The findings were published online in the Jan. 5/12 issue of the Journal of the American College of Cardiology.
All bioprosthetic aortic valves, whether TAV or SAV, can be expected to degenerate over time, said the researchers, led by Uri Landes, MD, of St. Paul’s and Vancouver General Hospital, British Columbia, and Tel Aviv University, Israel. This means life expectancy may exceed valve durability for many aortic stenosis patients, the authors said.
The study, therefore, aimed to compare outcomes for the initial bioprostheses – TAV versus SAV – after undergoing TAVR, which the researchers noted has become a key treatment for failed valves.
The principal endpoints were procedural success, procedural safety and mortality at both 30 days and 1 year.
The TAV and SAV cohorts both presented at a similar age (80 years) and had similar Society of Thoracic Surgeons risk (7.0% among TAV-in-TAV patients and 6.82% among TAV-in-SAV patients).
Data on the implantation date, model and size were collected, along with echocardiographic data at baseline, 30 days and 1 year on aortic valve area, mean and maximal gradients, and degree and mechanism of regurgitation.
Given possible differences in baseline clinical, echocardiographic and procedural characteristics between the two groups, propensity-score matching was applied with 330 (165:165) matched patients analyzed, showing the groups were “well matched, with no significant differences in baseline characteristics.”
However, TAV-in-TAV patients were more likely to be considered “frail” (41.2% versus 24.6%) and have multiple comorbidities such as diabetes, peripheral arterial disease and severe pulmonary disease, the researchers said.
TAV-in-TAV was done via transfemoral access for 88.6% versus 78.7% for TAV-in-SAV, and respectively used new-generation TAVs in 70% versus 65%, and self-expandable mechanisms in 48.3% versus 67.8%.
Of the TAV-in-TAV procedures, 120 (72.7%) were deemed successful, compared with 103 (62.4%) in TAV-in-SAV procedures (p = 0.045).This was driven by a numerically lower – but not statistically significant – frequency of residual high (≥20 mmHg) aortic valve gradient (14.6% versus 21.5%; p = 0.095), ectopic valve deployment (0.6% versus 3.3%; p = 0.081), coronary obstruction (1.2% versus 4.2%; p = 0.091), and conversion to open heart surgery (0 versus 3; p = 0.082), the researchers said.
At 30 days, aortic valve area was larger (1.55 ± 0.5 cm2 versus 1.37 ± 0.5 cm2; p = 0.040) and the mean residual gradient was lower (12.6 ± 5.2 mmHg vs. 14.9 ± 5.2 mmHg; p = 0.011). The differences remained significant at 1 year, the researchers said.
Early procedural safety was achieved in 116 (70.3%) TAV-in-TAV versus 119 (72.1%) of TAV-in-SAV patients (p = 0.715). Mortality for TAV-in-TAV versus TAV-in-SAV was 5 (3%) and 7 (4.4%) at 30 days (p = 0.570) and 12 (11.9%) versus 10 (10.2%) at 1 year (p = 0.633), respectively.
Higher rates of AR
The rate of moderate or greater residual aortic regurgitation was also found to be similar between the groups, the investigators said, but mild aortic regurgitation was more frequent after TAV-in-TAV at 49 patients (36.1%) versus 21 (17.2%) at 30 days (p = 0.003), and 49 (36.2%) versus 14 (12.1%) at 1 year (p = 0.001).
The researchers speculated on two potential mechanisms. First, because data on leak location are lacking, it could reflect the presence and persistence of paravalvular regurgitation associated with the initial TAV implant. Further imaging data are required, they noted.
Second, they highlighted learnings from recent in vitro testing suggesting that a relatively low implantation of a short-frame TAV into a tall-frame TAV with supra-annular leaflets may result in “leaflet overhang” of the outer valve and high regurgitation fraction.
“Accordingly, when we examined the rate of residual mild or greater AR in the subgroup of patients with balloon-expandable TAVs in self-expandable TAVs, it was higher than in other TAV-in-TAV combinations: 66% (n = 27 of 42) versus 54% (self-expandable–in–self-expandable; n = 46 of 70), 35% (balloon-expandable–in–balloon expandable; n = 11 of 32), and 29% (self-expandable – in-balloon-expandable; n = 6 of 21) (p = 0.038) at 30 days.”
The researchers called for further studies on outcome comparisons between initial TAV and SAV procedures when faced with secondary intervention procedures, covering various subgroups of patients with degenerated aortic valve bioprostheses.
They pushed for more studies to improve TAV-in-TAV outcomes as well as the upstream management of patients with aortic stenosis and otherwise long life expectancy.
They also called for further investigation into optimal TAV-in-TAV positioning, considering particular combinations of TAV designs and leaflets heights.
“Understanding better the expected outcomes of each type of reintervention may assist in upstream clinical decisions,” they said. “The present study is the first to compare the performance of TAVR in failed transcatheter versus surgical bioprostheses.”
In an accompanying editorial, UT Southwestern Medical Center’s Anthony A. Bavry, MD, MPH, and Dharam J. Kumbhani, MD, SM, noted that beyond the “obvious” limitations of an observational study, only 0.7% of all TAVRs in the study required TAV-in-TAV.
“Even among these, the investigators included patients as soon as 2 days after their initial TAVR implantation; therefore, this study can more accurately be said to examine freedom from reintervention, rather than structural valve degeneration per se,” they said.
In any case, they noted that the results of this study show valve-in-valve TAVR is feasible and associated with favorable outcomes among those with dysfunctional transcatheter or surgical prostheses.
Given the likely increase to come in patients who have undergone TAVR and will subsequently require repeat interventions later in life – almost certainly as TAV-in-TAV – longer-term data for these procedures will be crucial in the future from a lifetime management perspective, Bavry and Kumbhani added.
“At the same time, current and future TAVR implanters will need to … develop a sound understanding of the natural history of TAV-in-TAV procedures, as we are potentially on the cusp of a new valve epidemic.”
Landes U, Sathananthan J, Witberg G, et al. Transcatheter Replacement of Transcatheter Versus Surgically Implanted Aortic Valve Bioprostheses. J Am Coll Cardiol 2021;77:1-14.
Bavry AA and Kumbhani DJ. As Patients Live Longer, Are We on the Cusp of a New Valve Epidemic? J Am Coll Cardiol 2021;77:15-7.