DISCUSSION
Surgical repair of aneurysms and aortic dissections involving the aortic
arch is still challenging, carrying high mortality and morbidity. Our
experience with the first 70 consecutive patients treated with FET using
Thoraflex Hybrid has been overall satisfactory; technical success was
achieved in all patients even in the first part of our experience,
started after performing only conventional elephant trunk (ET) or
conventional surgery in acute dissection (ascending aorta or hemiarch
replacement). Our results show that the implantation technique for
Thoraflex Hybrid graft is doable and reproducible, also in acute
setting.
Correct cerebral perfusion during hypothermic circulatory arrest is one
of the main factors determining neurological
outcomes.7–9 Our strategy allows a uniform cerebral
perfusion throughout the operation, except for the short time needed for
LCA and LSA anastomosis, thus minimizing cerebral ischemia time. We
believe that this technical aspect is important to explain our
particularly good results in terms of neurological complications, with a
significantly lower overall incidence of permanent stroke (1.4%)
compared to data from similar studies.7 Shresta et al.
reported 8% of major CVA in their first experience in performing a FET
with the Thoraflex with a different brain protection strategy, while Chu
et al. reported a 5% stroke incidence.10,11 In
addition to our cerebral perfusion strategy, we believe that our
technique, avoiding direct cannulation and manipulation of cerebral
vessels, could reduce the embolism rate thus helping to minimize CVA
complications.
Another interesting finding from our study is the very low rate of
spinal cord injury which occurred in only one patient (1.4%) operated
for acute aortic dissection. We believe that our good results are due to
the use of a combination of 100 mm stented length (less intercostal
arteries coverage), Thoraflex Hybrid deployment in zone 2, short
circulatory arrest time and correct sizing of the stented
graft.12 Fiorentino et al reported a low overall
incidence of SCI (two cases of temporary isolated papaparesis) but only
in 150 mm distal stented grafts.13 Flores et al
reported a very high incidence of SCI in FET when the stented was
deployed at the lower level of the thoracic aorta.14
It has been reported that in Thoraflex implant the LSA anastomosis
remains the Achilles heel being too close to the collar
device.11 We overcome this problem by extending the
surgical incision with a small left supra-clavicular cervicotomy and
“elongating” the LSA with a tubular prosthesis, thus making the
anastomosis technically easier and achieving success in all cases. In
one case, not included in this series, we successfully used a
custom-made Thoraflex Hybrid, in which the plexus is separated from the
main part of the prosthesis, in order to make anastomosis easier,
improve operating times and correctly position the intra-thoracic
vessels.15
Overall survival for the entire cohort at 30 days was 90% (95% CI,
83.2—97.3), without statistically significant differences between
emergency and elective surgery (87.9% vs. in emergency vs. 93.2% in
chronic settings, P=0.312).
We believe that our results should contribute to encourage employing
this surgical strategy, especially in emergency setting where the FET
may be helpful particularly in patients with malperfusion and could
result in a definitive treatment. The idea of specialized centers with a
high volume of aortic surgery to treat both chronic and acute aortic
syndrome is now becoming paramount. There is a large consensus that
patients affected by acute aortic syndromes may benefit from treatment
at dedicated specialized aortic centers with significantly improved
outcomes and decreased mortality. Patients undergoing emergency repair
of acute aortic dissection by lower-volume surgeons and centers have
approximately double the risk-adjusted mortality of patients undergoing
repair by the highest volume care providers.16 We
think that the future treatment of acute type A aortic dissection is
going toward a total arch approach with standardized cerebral protection
that should more and more be delivered by specialist aortic centers with
expertise in this technique. In this case the Thoraflex Hybrid proved to
be an easy-to-implant prosthesis, making the brain protection strategy
easier and reporting a low complication rate.
Finally, an important aspect of our study is the relatively large number
of cases done in a short period of time in a single institution, thus
allowing for a significant reduction of multicenter studies bias. Other
series available in literature report results of a similar cohort of
patients but operated in different centers: the Canadian experience
enrolled 40 consecutive cases in 9 different centers, in about 3 years
of activity while the English experience counts 66 cases in 4 years from
9 centers throughout UK.17