Keywords
heart valve - transapical - percutaneous - reoperation - aortic valve and root - cardiology/cardiologist
Introduction
In the therapy of degenerated surgical aortic valve bioprostheses (SAVs), transcatheter
aortic valve-in-valve implantation (VIV) is increasingly being used successfully.[1]
[2] However, the sutureless SAV (Perceval S; LivaNova, London, United Kingdom), as a
representative of the latest generation of SAVs, has become established in the standard
surgical treatment of severe aortic valve stenosis (AS) and has gained popularity
worldwide due to its good hemodynamic outcome and short implantation time.[3] However, these SAVs also degenerate and are, therefore potential candidates for
VIV procedures. The new, self-expanding Allegra transcatheter heart valve (THV) (New
Valve Technology, Hechingen, Germany) has recently been shown its safety and feasibility
for VIV in patients with a small degenerated SAV, producing excellent hemodynamic
results.[4] Here we describe the first successful VIV with the Allegra THV into a degenerated
sutureless SAV.
Case Presentation
An 85-year-old female patient (weight: 84.3 kg, height: 163 cm) presented at our institution
with recurrent, worsening dyspnea with light physical activity. Three years previously,
she had undergone surgical aortic valve replacement with the Perceval S (size M) due
to severe AS via a partial upper mini-sternotomy. On admission, the transesophageal
and transthoracic echocardiography showed severe stenosis of the sutureless SAV with
a maximum/mean transvalvular gradient of 79/55 mm Hg, an effective orifice area of
0.6 cm2, an internal diameter of the SAV of 17 mm, a mild aortic regurgitation without any
paravalvular leakage (PVL), and severe tricuspid valve regurgitation. The left ventricular
ejection fraction was 55%, but the right heart function was impaired (tricuspid annular
plane systolic excursion of 15 mm). A multislice spiral computed tomographic (CT)
scan showed a typically shaped aortic root and ascending aorta without any calcification
of the aortic valvular cusps. The stent frame of the sutureless SAV was not dislocated
but was slightly oval shaped ([Figs. 1] and [2]). Due to the age and increased surgical risk EuroSCORE (European System for Cardiac
Operative Risk Evaluation) II: 6.21% and Society of Thoracic Surgeons Score: 11.9%),
the patient was considered to be a candidate for a transcatheter VIV by the heart
team. According to the manufacturer, the inner diameter of the size-M Perceval S was
between 19.5 and 21.0 mm. However, CT scan measurements were made to determine the
true internal diameter of the sutureless SAV (annulus area: 303 mm2, annulus perimeter: 62.4 mm, and effective annulus diameter: 19.3 mm; [Fig. 1A]).
Fig. 1 Multilayer spiral computed tomography. Annulus plane of the sutureless surgical aortic
valve bioprostheses (A), right coronary (RC) ostium height (B), stent frame of the surgical sutureless aortic valve bioprosthesis (NC = non-coronary)
(C), left coronary (LC) ostium height (D).
Fig. 2 Multilayer spiral computed tomography. Volume rendering of the aortic root with the
sutureless SAV inside. Ascending aorta (A), stent frame of the surgical sutureless aortic valve bioprosthesis (B), aortic annulus (C), left ventricular outflow tract (D), left ventricle (E), and left atrium (F).
Due to the implanted sutureless SAV with a very small effective, slightly oval-shaped
annulus, and the preprocedural high transvalvular gradient, we needed a THV in this
patient that could lead to an excellent hemodynamic result despite the unfavorable
preinterventional conditions. Therefore, we decided to implant a self-expandable,
supra-annular THV. Based on the promising data on its use in VIV therapy inside SAVs
with small true inner diameters,[4] we chose the 23-mm Allegra THV in this patient.
We performed the VIV procedure in a standard manner ([Video 1]) and used a 20 mm × 40 mm noncompliant balloon for predilatation ([Fig. 3B]) to modulate the annulus of the SAV more round. The Allegra THV was first positioned
optimally within the annulus of the sutureless SAV and the “permaflow mode” was activated
([Fig. 3C]). Subsequently, the lower part of the device was freed by “tip release” ([Fig. 3D]). No postdilatation was needed in view of the excellent hemodynamic results with
an invasive transvalvular gradient of 5 mmHg. Based on The Valve Academic Research
Consortium II criteria, no major adverse event occurred during the hospital stay.
Hypostatic pneumonia was treated with systemic antibiotics, and a puncture evacuated
pleural effusion on the right side. The patient was discharged 9 days after the procedure
to a rehabilitation center with a maximum/mean transvalvular pressure gradient measured
by transthoracic echocardiography of 19/9 mm Hg and no apparent PVL.
Fig. 3 Fluoroscopy of the transcatheter aortic valve-in-valve implantation procedure. Preimplantation
aortography (A), predilatation valvuloplasty (B), permaflow mode (C), tip-release (D); final result (E), and postimplantation aortography (F).
Video 1 Fluoroscopy of the transcatheter aortic valve-in-valve implantation procedure.
Discussion
Due to the natural degeneration process of SAVs, the frequency of VIV in sutureless
SAV will increase in the coming years. Considering the very promising hemodynamic
results of the Allegra THV,[4] it is an excellent candidate for use in VIV procedures in SAVs with a small true
internal diameter. However, it has never been used in degenerated sutureless SAV.
A strong argument for using self-expanding THVs in VIV procedures is less-structural
valve deterioration in the long-term compared with balloon-expandable valves in the
therapy of native AS.[5] This difference is likely to become more critical as the native aortic valve annulus
diameter or the inner diameter of a degenerated SAV decreases over time.[4] Moreover, the self-expanding THV is superior in the short-term hemodynamic outcome
after VIV therapy.[6] The benefit of the self-expanding THV is that they have fewer problems with incomplete
deflation or distortion within a degenerated SAV. The supra-annular valve design is
less vulnerable and usually results in a larger effective orifice area and a lower
transvalvular gradient, almost regardless of a small and/or asymmetric annulus. Despite
their excellent hemodynamic long-term outcome, above-mentioned positive features,
and the recapture ability of some devices, they are used in less than one-third of
VIV in latest-generation SAVs.[7] Unfortunately, with some self-expanding THVs, accessing the coronary arteries after
VIV can be difficult. However, due to a sophisticated closed-cell, diamond-shaped
configuration of the nitinol stent frame with a variable cell size distribution, the
Allegra THV allows easy access for potential percutaneous coronary intervention at
a later stage. With the implantation of the popular self-expanding Evolut R THV (Medtronic
Inc., Minneapolis, Minnesota, United States) in our case, postinterventional access
to the coronary arteries would have been nearly impossible. Also, the stent frame
configuration of the Allegra THV leads to improved coronary perfusion and very low
postinterventional transvalvular gradients, even after VIV.[4] In our case, we were able to reduce the maximum/mean transvalvular pressure gradient
from 79/55 mm Hg to 19/9 mm Hg. Furthermore, different levels of radial force enhance
a safe anchoring of the Allegra within the aortic annulus. The six radiopaque gold
markers placed at the valve plane level to indicate the bottom part of the semilunar
valve assist the operator in positioning this THV corrected, especially during VIV.
The prosthesis's ventricular inflow section is covered by a bovine pericardial sealing
skirt to mitigate paravalvular prosthetic regurgitation. Unfortunately, no direct
comparisons of the performance in VIV of the Allegra and other self-expanding THVs
have been made. However, the Evolut R and the Portico (St. Jude Medical, Inc., St.
Paul, Minnesota, United States) were compared in a matched analysis based on the VIVID
registry; here, the Evolut R (n = 108) was superior to the Portico (n = 54) in terms of postinterventional effective orifice area and mean gradient (1.67
vs. 1.31 cm2; p = 0.001 and 14 ± 7.5 vs. 17 ± 7.5 mm Hg; p = 0.02, respectively).[8] In the multicentric VIVAL trial (n = 30) of the Allegra in VIV procedures, these parameters (effective orifice area:
1.40 ± 0.52 cm2, mean gradient: 14.8 ± 6.5 mm Hg)[4] are comparable to those for the Evolut R from the VIVID registry. In our case, the
good hemodynamic properties of the Allegra were confirmed, even in the small annulus
of the degenerated sutureless SAV.
Conclusion
A VIV procedure using the Allegra THV into the Perceval S sutureless SAV is feasible
with an excellent hemodynamic result.
