Replacing the root, a burden on mid to long term outcomes?
Yang B and colleagues 5 reported a set of contrasting
results from their single center study, compared to various other
articles as seen in Table A. From a cohort of 94 patients (10 patients
had no root procedure), the 4 year Kaplan-Meier survival for the small
sample size of 45 patients undergoing root repair was 91%. The patients
in the root replacement group underwent either the Bentall (n=24), or
the VSRR David procedure (n=15). The Bentall group was independently
compared with the conservative repair group, and the reported 4 year
survival was significantly lower at 39% (p = 0.03). The authors suggest
that previous studies which may have caused higher mortality in the root
repair groups were caused by the use of surgical glue which was not used
in this study.5 Following adjustments made for; “age,
sex, coronary artery disease, pre-operative severe aortic insufficiency,
previous cardiac surgery, and cardiac tamponade” 5,
it was then stated in this study that the mortality risk was comparable
(p=0.24). In addition, no statistically significant difference was
reported between root repair and VSRR David procedure
(p=0.25).5 The retrospective nature and short follow
up period (mean of 22 months), as well as the fact that the study is
based on a single surgeons experience, adds significant limitations to
the conclusions being drawn.
The study published by Hysi I and colleagues (2015)7have reported outcomes showing improved long term survival for complete
aortic root replacement, contrasting the results to Yang B and
colleagues.5 This study had a far longer mean follow
up period of 9.1 years (109.2 months), compared to the study by Yang B
and colleagues discussed above which had a mean follow up time of 22
months only. In addition to this, Hysi I and colleagues reported their
long term survival outcomes at 5, 10 and 15 years showing continuously
at multiple time points that the group of 82 patients that underwent the
Bentall (n=77) or Tirone David (n=5) procedure, showed far favourable
results (p=0.03)7 compared to the group that underwent
supracomissural repair. This is in contrast to the aforementioned study,
where the authors had only reported outcomes for a single point in their
follow up time for a 4 years survival result.5 However
it is again important to appreciate that as the aortic root replacement
group was reported to be more recent in the study7compared to conservative repairs, the study does acknowledge this may
have been a source of bias as a consequence of surgical strategy
evolution.
Similarly to the discussed short term outcomes, various different
studies4, 19, 20 have reported no statistically
significant long term results when comparing these mentioned approaches
for aortic root management. It is important to appreciate, however, the
very significant indications and requirements for a radical root
replacement method to be implemented at all. Patients that underwent a
more extensive approach of root replacement were generally younger, and
with fewer co-morbidities, as well as more likely to have had a more
extensive dissection. The presentation of poor morphology and physiology
of the root, as well as the presence of connective tissue diseases, were
strong indicators for root replacement across the studies in this
review. Furthermore, the highly limiting retrospective and single-center
characteristics are vital for consideration when reviewing the data of
articles in Table A.