Comment
This study was a retrospective, single-center report of early and
long-term results from OPCAB for octogenarians under an OPCAB-first
strategy and illustrated real-world clinical practice. Early results
were good in terms of mortality and morbidity rates, with the exception
of post-operative atrial fibrillation. Long-term results were also good.
As post-operative results for the old group were not inferior to those
for the young group, we believe that the OPCAB-first strategy for all
generation becomes a good therapeutic option for surgical
revascularization in octogenarians.
For elderly patients, early extubation and early recovery from bed rest
are very important to prevent disuse atrophy, which can lead to
post-operative complications. In the present study, post-operative
intubation time and intensive care unit stay did not differ
significantly between young and old groups. We adjusted graft usage in
elderly or ill patients to shorten operative time, and the old group
displayed a shorter operative time than the young group (Table 2).
Shorter operative time and OPCAB with multidisciplinary care, including
anesthetic drug usage and intra-operative volume control could
contribute to the achievement of early extubation and a short stay in
the intensive care unit, even for old patients.
Some reports have demonstrated that bilateral ITA usage was associated
with an increased frequency of post-operative
mediastinitis16,17. In the present study, however, the
overall incidence of mediastinitis was low, at 0.8%, despite bilateral
ITAs were used in 79.8% of all cases. This might be because bilateral
ITAs were harvested in skeletonized fashion with a harmonic scalpel in
our institution18. Furthermore, the surgeons who
harvested bilateral ITAs were very experienced due to our strategy, and
bilateral ITAs were used in nearly 80% of all cases.
Concerning the graft design, the radial artery was attractive as the
third arterial graft14. However, in the present study,
nearly 14% of patients were receiving hemodialysis before the
operation, and radial artery harvesting was thus avoided in
consideration of the fact that many patients with coronary artery
disease potentially have reduced renal function and even
non-hemodialysis patients might require future shunt establishment. As a
matter of fact, 6.3% of the old group required temporary post-operative
hemodialysis, even though OPCAB can reportedly lower post-operative
kidney injury compared to conventional CABG19,20.
The frequency of post-operative cerebral infarction did not differ
between groups, but was 1.8% overall. Three of the 13 patients with
post-operative cerebral infarction were considered to have
intraoperative cerebral infarction, comprising two emergent cases, and
one cases with carotid stenosis. The “intra-operative” cerebral
infarction rate was low, at 0.4%, probably because OPCAB could avoid
aortic cannulation or cross-clamping11. The remaining
10 cases suffered delayed cerebral infarction on POD3 or later,
including 5 cases of paroxysmal atrial fibrillation, and 3 cases in
hemodialysis patients. Methods to reduce “post-operative” cerebral
infarction are needed. We adopted double anti-platelet therapy, with
aspirin at 81 mg/day and clopidogrel at 75 mg/day, with the aims of not
only reducing graft occlusion15, but also reducing the
risk of cerebral infarction21,22. However, our results
indicate that changes in this post-operative regimen may be warranted.
Adjustment of antiplatelet/anti-coagulation therapy, including heparin
administration or use of warfarin or direct oral anticoagulants, might
be required. Not only care, but also prevention of atrial fibrillation
are the rational approaches to reducing post-operative cerebral
infarction. This needs to be taken into consideration, using approaches
such as aggressive usage of beta-blockers23.
Long-term results were satisfactory considering the age of our patients,
and were better than what has been reported
elsewhere4,5. These findings were comparable with
those from previous reports; once old patients survive the surgery,
long-term prospects are good6. In the present study,
the 7-year survival rate was 48.6%, meaning that nearly half of the
patients reached their nineties. This was close to the life expectancy
of the general population in Japanese at age 80, which is about 9 years
for Japanese men and 12 years for Japanese women3.
The Clinical Frailty Scale is a simple tool to semi-quantitatively
assess patient frailty24. This scale can predict late
mortality in certain cases25,26. In the present study,
as preoperative Clinical Frailty Scale scores differed significantly
between groups, the mean score in the old group was relatively low, at
3.2. Despite our no-refusal policy, some degree of selection bias would
have naturally been introduced by referring doctors, cardiologists or
even surgeons. This speculation was supported by the fact that 85.1% of
patients were able to return home from hospital directly, indicating
that daily activity of octogenarian patients was well preserved in this
study. From another perspective, our results implied that those patients
with a Clinical Frailty Scale score around 3 would have a high
possibility of overcoming OPCAB, even in octogenarians.
The present study had several limitations. First, the results in this
study represent our clinical experience with a consecutive series of
isolated surgical CABG. The number of patients was small and selection
of surgical revascularization for patients introduced a huge selection
bias. Nonetheless, our results encourage us to keep providing open-heart
surgery to octogenarians with ischemic coronary disease where feasible.
A second limitation was the retrospective design of the study, with no
comparisons between OPCAB and conventional CABG made within groups.
Whether OPCAB provided more benefit to old patients than conventional
CABG thus could not be assessed. However, as we chose OPCAB as the
first-line procedure, nearly 97% of cases were accomplished using
OPCAB. We believe that the more we become familiar with the procedure,
the more the operative results that can be provided to elderly patients
will stabilize11.
Lastly, we did not assess major adverse cardiac events over the long
term. The long-term symptom-free rate was therefore unknown.
Nevertheless, our OCPAB-first strategy could provide elderly patients
with a comparable survival rate to Japanese octogenarians in the general
population.