Discussion
This study presents the first examination of cost data on sutureless,
rapid deployment valves in the United States. Like many studies we
showed shorter cardiopulmonary bypass and aortic cross clamp times with
good outcomes. Also shown was an initially high permanent pacemaker rate
that declined over time. Hospital costs between SLV and standard sutured
valves were not different.
Overall, outcomes with SLV have been good. The Europeans have a longer
and more extensive experience. In reviewing that literature the early
reports in isolated AVR were encouraging, showing safety and good
hemodynamic results.4,5 In the Cavalier
Trial,17 Perceval
valves were placed in 628 patients in several European centers from 2010
to 2013 with a mean cross-clamp time of 32 minutes and post-operative
mean gradient of about 10 mmHg. Thirty day overall and valve-related
mortality rates were 3.7% and 0.5%, respectively. The valve explant
rate was 0.6%, and stroke rate was 2.1%. Five year data were presented
by Shrestha, et al. in 2016 and showed similar short-term outcomes in
731 patients undergoing AVR from 2007 to
2012.18 There was a 1%
incidence of late major paravalvular leak. Early mortality was about
2%, 1 year 8% and 5 year was 25%. The average mean gradient at 5
years was 7.8 mmHg.
The post-operative mean gradients reported in studies of rapid
deployment valves are interesting and may suggest a learning curve. When
an oversized SLV is placed the mean gradient may be elevated due to
decreased leaflet excursion. In a large German registry review of over
20,000 patients undergoing isolated SAVR three rapid deployment valves
were compared. The Perceval valve was less likely to be a smaller sized
valve (≤ 21 mm) (Perceval 10% of patients, balloon expandable INTUITY
valve (Edwards Lifesciences, Irvine, California) 25%, and
self-expanding, nitinol-based 3F Enable valve (Medtronic, Dublin,
Ireland) 27%; P<.001). The median postoperative mean aortic
valve gradient was highest in the Perceval (14 mmHg, INTUITY 9 mmHg and
Enable 10 mmHg; P<.001), and permanent pacemaker was highest
with Perceval (11%, INTUITY 7% and Enable 7%; P<.02). It is
common for surgeons to place the largest valve possible, but
right-sizing of this valve allows for optimal hemodynamics and avoidance
of permanent pacemaker. Subsequent studies have shown the PPM rate can
be reduced by changes in implantation
technique.19
Comparisons have been made to stented surgical valves and transcatheter
aortic valve replacements (TAVR). A 2014 study compared Perceval to
Carpentier-Edwards Perimount aortic prostheses showing lower CPB and
cross-clamp times with
SLV.20 The
post-operative peak gradients were lower with SLV, but the average mean
gradients were not different in similarly sized valves (approximately 23
mm for both groups). There was no difference in PPM in this small study.
A 2015 study from France compared hemodynamic performance of small
Perceval prostheses in elderly patients with larger size Perceval valves
and found no difference in post-operative mean gradient (10.3 mmHg for
small valves and 11.3 mmHg for medium and large valves; P=.20), indexed
effective orifice area (0.84 cm2/m2for small and 0.86 ; P=.76) or presence of patient prosthesis mismatch
(absent in 45% v. 43%, moderate in 45% v. 39% and severe in 10% v.
20%; P=0.6). At a median follow up of 1.5 years the echo measurements
and survival did not differ. This suggests that a stentless valve in the
small aortic root can provide good
hemodynamics.21
Recently published industry sponsored clinical trials in low-risk
patients with severe aortic stenosis have shown that transcatheter
aortic valve replacement (TAVR) is at least comparable in short term
outcomes when compared to surgical aortic valve
replacement.22,23In both trials TAVR resulted in less stroke, bleeding, atrial
fibrillation and shorter length of stay with similar valve performance
at one year. The type of surgical valve used in these trials was left to
the surgeon, and it is not clear if certain prostheses have any
advantage. There have been no randomized control trials comparing
sutureless valves to date. Several retrospective studies comparing older
TAVR technology showed some advantages to SAVR with sutureless valves
(lower rates of vascular complications, paravalvular leak, permanent
pacemaker, and renal failure) which have been largely mitigated with
advancements in TAVR technology. Interestingly, two studies with
mid-term patient matched outcome data showed no difference in survival
at one year, but a survival advantage for Perceval at two years; 97.3%
vs. 86.5%, P = .015 and 94.9% vs. 79.5%, P =
.02.24,25There is great interest in understanding how TAVR will compare with SAVR
in mid- and long-term outcomes. Similar to our findings, a number of
studies have demonstrated that sutureless valve technology facilitates
minimally invasive approaches. The Sutureless and Rapid Deployment
International Registry published results of 1935 patients undergoing
SAVR with sutureless and rapid deployment valves and showed 73% were
implanted in a minimally invasive
fashion.26 In contrast,
overall use of mini approaches to SAVR have been reported to be 15% in
the United States, 12% in the United Kingdom and 25% in
Germany.27 It is clear
that for SAVR to compete surgeons should work to improve outcomes and
utilize minimally invasive approaches for patients who are not currently
candidates for transcatheter technology.
There have been concerns raised about possible complications associated
with sutureless valve technology. There have been reports of
paravalvular leak, especially in the early
experience.28 The cause
of paravalvular leak is often due to incorrect sizing of the valve.
There is certainly a learning curve associated with new valve technology
and ensuring proper sizing is important. It has been the practice of our
group to not accept more than trace paravalvular leak on the
intraoperative post implant echocardiogram. Thrombocytopenia has also
been described. In one study the average platelet count at discharge
after Perceval implantation was 102,000 ± 28,000 which was significantly
lower than Edwards Intuity rapid deployment
valve.29 Another study
compared Perceval (n= 72 patients) to Perimount Magna Ease (n=101
patients) and showed a greater maximum drop in platelet count at a mean
of post-operative day 2.3 (58% in Perceval vs. 44% in Magna Ease;
P=.0001), less likely recovery to pre-operative levels by discharge
(26% in Perceval and 44% in Magna Ease; P=.018), and more red blood
cell (P=.007) and platelet (P=.009) transfusion with Perceval. We did
not appreciate a significant difference in bleeding rates or
transfusion, and often treated the thrombocytopenia expectantly if there
were no bleeding complications. Migration is extremely rare, but has
been reported.30 Two
clinical situations have been described. The first is in double, aortic
and mitral, valve replacement where the two prostheses interact and the
sutureless valve becomes unstable. There appears to be potentially
predictive factors including a short aorticomitral curtain (<6
mm) and the angle of the aorta and mitral annuli. These factors are
currently being studied. The second is infective endocarditis after
sutureless valve placement. If there is a large annular abscess the
valve may become unstable, and at risk of migration. Our experience with
a single case has suggested that early surgery in these cases may be
beneficial. Durability of the valve is being studied as well. It has
been shown in the European literature that the 5-year durability data is
reasonable. In a 2016 multicenter paper, Shrestha et
al.18 showed a late
(more than 30 days after implant) explant rate of 1.5%, major
paravalvular leak rate of 1%, endocarditis 1.6% and AV block in 1.4%.
At the 2019 American Association for Thoracic Surgery annual meeting Dr.
Meuris presented 11-year data on 486 consecutive patients at
Leuven University Hospital. In
their series there were no explants for structural valve degeneration.
The manuscript and additional long-term data are pending. In our current
series no valves have been explanted for structural valve degeneration.
However, It does appear that sutureless valves will offer a good
platform for future valve in valve TAVR as it is essentially a stentless
valve.31 For a small
Perceval valve a 23 mm Edwards S3 TAVR valve can be considered.
There are economic considerations when using new technology, and date
there have been no data on cost in the United States for this procedure.
Sutureless and rapid deployment valves often cost more than standard
aortic prostheses. At our institution, during the study period, the
Perceval valve cost approximately $5,670 more than sutured valves. A
study from Germany showed use of sutureless valves resulted in lower
cost based on savings in diagnostics and hospital length of
stay.32 In our current
study we found that a higher pacemaker rate incurred extra cost. There
have been excellent descriptions of techniques to reduce pacemaker
rate33, and our group
has been able to continue decreasing the need to post-operative
permanent pacemakers.