Surgical Technique
In an era ruled by a rising drift towards TAVI procedures, there has
been a need to reduce the physiological impact of a surgical aortic
valve replacement (sAVR). Sutureless implantation can shorten the aortic
cross-clamp and cardiopulmonary bypass times (1,2) and facilitate
minimally invasive sAVR (3), whereas the lack of a proper stent enables
improved hemodynamics (4), especially in case of small annuli. The
Perceval valve (LivaNova, London, United Kingdom) consists of
double-sheet bovine pericardium leaflets and a self-anchoring,
self-expanding and elastic nitinol alloy stent, covered by a thin
Carbofilm™ coating for improved biocompatibility. Due to its nitinol
alloy stent height, the Company recommends to do the aortotomy
transversely and higher than for traditional AVR, about 3.5 cm above the
aortic annulus. The reason for this recommendation is that the Nitinol
stent is longer than a traditional valve frame and if the aortotomy is
too low, the distal portion could interfere with the closure of the
aortotomy or may be caught within the suture. Catching the frame in the
aortotomy suture bears the risk of dislodging the valve into the aortic
root.
In our experience, we have devised two different scenarios where a
Perceval valve might be the best option, even though a conventional
extended aortotomy has been necessarily (Fig. 1):
- Unexpected small annuli, where - due to the narrow outflow tract
available - a sutureless/stentless solution might give a larger
effective orifice area (EOA), avoiding patient prosthesis mismatch
(PPM) (6), improving the hemodynamic performance and the valve
durability. We call this scenario “unplanned Perceval implantation”,
because we are forced to change the choice of the prosthesis after the
direct inspection of the annulus and the left ventricular outflow
tract (LVOT).
- Aortic valve redo cases (5) in small annuli. Technically speaking, the
closest approach to the aortic annulus makes easier the valve removal:
the annulus has to be thoroughly cleaned to allow a perfect seal, so
an extended aortotomy deep down the non-coronary sinus is often
required. Of course, the advantage of a larger EOA as described in the
previous point, is extremely valuable in this setting, too.
Based on our experience, the easiest way to implant a Perceval valve
after making an extended aortotomy is “rebuilding” the aortic root
wall up to the point where the recommended transverse aortotomy would be
made. That is done with a Blalock suture of 4-0 or 5-0 prolene, pairing
in an edge-to-edge fashion the aortic root wall (Fig. 2). Once the
aortic root is rebuilt, the suture is tied: indeed the frame radial
force could easily loosen the suture if that was not properly fixed. Due
to its narrow profile, the Perceval valve can be easily fit in the
remaining opening. After the implantation, the aorta is sutured in the
usual manner. We would point out the need of symmetry when suturing the
aortic root wall; as it is well known, if the frame encountered a not
circular and smooth inner aortic surface, there would be a high
probability to have a folding issue after the implantation; with an
edge-to-edge well-paired suture it’s possible to restore the original
inner shape and surface.
We briefly reviewed our surgical clinical records; since the Perceval
valve became available in our Institution in 2016, we placed that
bioprosthesis in 19 cases of ”unexpected small annuli” (table 1) and 27
redo cases for structural aortic valve deterioration (Table 2).