Discussion
Our results support that AVSRR for BAV is a safe option, with low
mortality and low morbidity, good valve stability, and good quality of
life many years after surgery.
The characteristics of our patient population were similar to those
reported in other studies.(8, 11, 15) Patients were in a good state of
health, which can be explained by the relatively young age of 47.4±12.5
years and the preserved left ventricular ejection fraction. Most of our
patients had mild symptoms, with 3.9% having NYHA functional class III
or IV, and 96.1% with Canadian Cardiovascular Society class I.
BAV is the most common congenital cardiac malformation (1–3), which can
represent a health burden because some patients develop valvular and/or
aortic complications. Severe aortic stenosis is typically managed with
valve replacement, whereas patients with aortic regurgitation are
candidates for valve repair. The reference treatment involves a
composite replacement of the valve and aorta, i.e., the procedure of
Bentall.(4) Generally, the population with BAV associated with aortic or
valvular disease is young (3, 16), and with valve replacement, the use
of a mechanical prosthesis with anticoagulation medication requires an
altered lifestyle in some cases.(5, 17) Moreover, mechanical prosthesis
may predispose patients to higher rates of thromboembolic events.(3) For
these reasons, AVSRR techniques have been developed.
“Valve-sparing root replacement” is a collective name for multiple
kinds of procedures, (7) but in general, two principal techniques are
used: remodeling or reimplantation. For three decades, both approaches
have yielded good results, including good long-term outcomes in the case
of tricuspid aortic valves. (8,11,15) However, our center has preferred
the Tirone procedure because it provides a complete stabilization of the
root, including the annulus. After Modine et al. described a modified
technique using a single inflow suture line, we adopted that, as well.
(18) In cases of regurgitant BAV associated with aortic dilation,
preservation or repair seems to be an attractive alternative to
replacement. If a patient does not want a mechanical prosthesis, a
bioprosthesis also is an option, but the limited durability does not
make it ideal for younger individuals, and bioprostheses may increase
risk of endocarditis and reintervention. (5,19,20)
Most of our cases were Sievers type I (60.8%), which reflects the
natural distribution of BAV type.(21) We did, however, find a relatively
frequent occurrence of type 0 (29.4%) compared to rates that Sievers et
al. reported (7%). (21) Regarding intra- and post-operative outcomes,
our data are in line with reports from other groups and confirm that
AVSRR, such as the Tirone procedure, can be performed in patients with
BAV with very low perioperative risks for morbidity and mortality
(0%–2.5%) (8,11–13,16). Most of our patients had elective surgery
for the Tirone procedure without other associated surgery to exclude
confounding from other procedures. Holmgren and colleagues, however,
still reported that even combined surgery was not associated with higher
observed or relative mortality.(9)
We needed to use a graft size ≤26 mm for three women with lower heights
(146, 155 and 157 cm, respectively), in whose cases the rings were
measured as <20 mm at the TEE, <26 mm on computed
tomography, and ≤24 mm with the Hegar sizer. This choice has not
constituted a problem for the post-operative evolution, and during a
follow-up of more than 5 years, we have noted no aortic regurgitation,
their mean gradients were respectively 3, 9 and 11 mmHg, and their left
ventricular ejection fraction measures were 60%, 60% and 65%. For
patients who had an aortic root <45 mm, we offered the Tirone
procedure because they had a severe aortic insufficiency. The aim is to
stabilize the root for the lifetime.
There were no in-hospital deaths or deaths at 30 days, emphasizing that
this operation can be performed extremely safely in experienced hands.
There also were no perioperative strokes, and only one patient (2.0%)
had acute coronary syndrome that presented as cardiogenic shock at 4
postoperative days. This case was particular because extracorporeal life
support was needed for 5 days, two stents were placed in the right
coronary artery, and dialysis was temporarily required. At the time of
this writing, more than 4 years after the surgery, the patient was in
good health, and TEE show a left ventricular ejection fraction of 65%,
no remodeling of the aortic valve, and no aortic regurgitation. One
patient (2.0%) needed reintervention for bleeding, indicating that in
an experienced center, this procedure can be performed with low
mortality rates.(11,16)
With our experience now extending back 15 years, we have seen stable
aortic valve function in most cases. Here, we have presented outcomes at
5 years and 10 years. Although we have complete follow-up for the first
case 15 years ago, a patient who is alive and doing quite well with no
complications, we had only 17 patients with 10–15 years of follow-up.
This early paucity can be explained by the fact that this technique was
progressively integrated into the surgical options on offer and was used
with increasing frequency after the first 5 years following its
introduction.
As observed previously, three patients needed a reintervention after
some lengthy period following the first surgery, an outcome that is
better than that seen with bioprostheses in this age group. (20) When
reoperation is necessary, the surgery is straightforward and consists of
excising the native valve and implanting a prosthesis, as we did for the
patient who had mitral insufficiency associated with moderate stenosis
at 4.5 years following their Tirone procedure. Theirs is the only case
in which we reoperated for reasons related to aortic stenosis, so in our
15 years of experience, the probability of developing relevant aortic
stenosis has been very low. (5,16) As Schneider and colleagues also
found, the incidence of endocarditis was low, with two patients in 15
years needing reoperation with Bentall’s mechanical procedure. (12)
We also can indirectly assess quality of life based on medication needs.
During follow-up, we noted that only three patients needed
anticoagulants, including the two patients reoperated with Bentall’s
procedure, and that six patients are taking no medications at all. For
us, this information provides another argument supporting valve-sparing
procedures especially in the young population.