DISCUSSION
The aim of this study was to compare the mid-term outcomes of
intermediate-risk patients operated on for severe AS with RDAVR with
INTUITY, or TAVR with Sapien 3 valve. The main findings were: (1) At two
years, there was a significantly lower occurrence of the composite
criterion (death from any cause, disabling stroke and/or
rehospitalization) in RDAVR group. (2) This result was mainly driven by
less rehospitalization related to CHF in RDAVR group (3) Both valves
provide a similar rate of PPM, PVR≥ 2 and PM implantation.
The recent progress in new generation THV urges surgeons to rethink
surgical techniques. The INTUITY Valve is a hybrid option between
conventional AVR and TAVR. RDAVR allows removal of the native leaflets
as would a surgical procedure and is balloon-expanded as for TAVR. This
enable to reduce CPBT by nearly 20 minutes compared to conventional AVR
[18]. However, the clear benefit of this reduction on morbidity and
mortality has not been demonstrated so far [19]. Thus, authors
propose to limit its implantation to elderly patients in need of a
combined surgery or in case of a complex aortic valve reoperation
[20]. Meanwhile, indications for TAVR in patients with severe,
symptomatic AS have been widely extended to younger patients since
recent data showed that TAVR is non-inferior to surgery in intermediate
and low risk patients [5,6].
While several studies have compared RDAVR with conventional
AVR[13–15] and TAVR with conventional AVR[4–6], literature is
poor on the direct comparison of RDAVR with INTUITY to TAVR with Sapien
3.
In this study, RDVAR with INTUITY provides better outcomes than TAVR
with Sapien 3 at two-years FU. Based on the same composite criterion
used in PARTNER 3, we showed a significantly lower rate of death from
any cause, disabling stroke and/or rehospitalization in RDAVR group when
compared to TAVR group. This was mainly driven by a lower rate of
rehospitalization related to CHF in RDAVR group.
The ultimate goal of AVR is to decrease left ventricular (LV) afterload
to allow LV mass regression and improve LV compliance and myocardial
perfusion. This enhances survival and quality of life and decreases the
risk for CHF.
CHF after TAVR is already known as a powerful predictor of mortality and
multiple CHF readmissions predicted the highest mortality rates
[21]. CHF symptoms develop usually in case of incomplete LV
afterload relief, untreated mitral regurgitation or residual myocardial
ischemia leading to increase in left atrial pressure and sPAP
[22–24]. Interestingly, sPAP was significantly higher in TAVR group
at one-month FU when compared to RDAVR group. Moreover, LVEF was similar
in both groups as well as the rate of MR≥ 2. This suggests that other
mechanisms could be involved in the increased risk of CHF in TAVR group.
Most TAVR patients had a history of coronary artery disease (CAD) but no
standardized revascularization strategy was endorsed in the absence of
guidelines [25]. Hence, the timing to perform percutaneous coronary
intervention (PCI) before or after TAVR was at the discretion of the
heart team. We assume that postponing PCI could have increase the risk
of ischemic myocardial injury after the TAVR procedure. Conversely, most
RDAVR patients had combined procedures with coronary artery bypass
grafting (CABG), limiting the risk of residual myocardial ischemia, LV
diastolic or systolic dysfunction and CHF.
Another explanation to understand the higher rate of CHF after TAVR
could be an increased incidence of significant PVR. PVR is known as a
powerful predictor of mortality and CHF after TAVR [26]. PVR could
limit LV hypertrophy regression by exposing patients to a residual LV
afterload, diastolic dysfunction and impaired coronary flow reserve.
However, we didn’t find any difference regarding the occurrence of PVR≥
2 in both groups. The rate of PVR≥ 2 was low in TAVR group(2,17%) in
accordance with previous results reported in the literature [27].
The occurrence of PPM can also promote CHF after TAVR [28]. PPM
leads to a lesser LV mass regression owing to the persistence of a
residual LV afterload. However, the rate of moderate/severe PPM was
similar between both RDAVR and TAVR groups in our study and could not
explain a significantly higher rate of CHF in TAVR group.