Corresponding Author:
Prof GD Angelini, MD,MCh,FRCS, FMedSci
British Heart Foundation Professor of Cardiac Surgery,
Bristol Heart Institute
Bristol Royal Infirmary,
Upper Maudlin Street BS2 8HW
Bristol, UK
G.D.Angelini@bristol.ac.uk
Conflict of Interest : none
Funding: This work was supported by the British Heart
Foundation and the NIHR Biomedical Research Centre at University
Hospitals Bristol and Weston NHS Foundation Trust and the University of
Bristol.
Key words : Hybrid robotic coronary revascularization, OPCAB,
endoscopic CABG
Hybrid coronary revascularization (HCR) requires left internal thoracic
artery (LITA) graft to the left anterior descending (LAD) coronary
artery combined with percutaneous coronary interventions (PCI) for the
non-LAD lesions. Robotic totally
endoscopic techniques to perform the LITA to LAD graft, coupled with
PCI, provides the least invasive option to achieve HCR. In the study by
Torregrossa et al, this strategy of HCR has been compared with
conventional off-pump coronary artery bypass grafting (OPCAB), in the
specific cohort of women with two vessel coronary artery disease(1).
Apart from reporting a niche strategy for HCR, where limited data is
available, the authors have used propensity matched groups for
comparison, and have also provided long term outcomes which add further
value to the paper. The main
findings of the study include significantly shorter hospital stay and
requirement for blood transfusions, along with similar long-term
outcomes in women undergoing HCR. Based on these observations the
authors suggest that the shorter hospital stay and lesser requirement
for blood transfusion would lead to lesser utilization of hospital
resources and result in a financial benefit.
The findings of this study are supported by several other studies.
Reduced blood transfusion requirements is indeed the most consistent
reported benefit of HCR (2–5). However, while the risk of bleeding and
need for blood transfusion has been reported to be lower it is important
to remember that considerable
variations exist in the definition of HCR. HCR can be single stage, or a
two-stage procedure carried out typically during the same hospital
admission, however, two separate hospital admissions may also be
required. The sequence could be CABG followed by PCI or vice versa.
Surgical revascularization is carried out predominantly using OPCAB, but
on-pump techniques have also been used. Besides, full and partial,
midline and parasternal sternotomies, lateral thoracotomies, robotically
enhanced (LITA harvest only) as well as totally endoscopic CABG have all
been used as part of HCR(6).
In the study by Torregrossa et al, total endoscopic LITA to LAD
anastomosis was performed but variations existed both in stages and in
sequence of HCR. Nearly half (50.9%) the cases had HCR performed in the
same admission. In the remaining patients HCR was carried out as a
two-staged procedure where CABG was performed before PCI in majority of
cases (36.4%) and after PCI (12.7%) in a smaller cohort. The number of
stages and the sequence in which PCI and CABG are carried out are often
dictated by specific clinical needs which in turn affect the outcomes.
The PCI first strategy is most commonly undertaken in patients
presenting with acute coronary syndrome due to non-LAD culprit lesions.
The need for dual anti-platelet agents and incomplete reversal of
heparin after surgery make these patients potentially at risk for
increased bleeding(7). Outcomes are also influenced by whether the HCR
is single stage or a two-stage procedure with staged HCR deemed better
than single stage HCR with respect to risk of bleeding and
re-interventions, and single stage HCR thought to be superior in terms
of major adverse cardiac and cerebrovascular events (MACCE) rates(5).
Thus, the different strategies of HCR do not lead to similar outcomes.
Furthermore, the findings of one strategy cannot be extrapolated to the
entire group and studies reporting different strategies of HCR, should
ideally provide more granular data.
The shorter length of hospital stay with HCR seen in this study has also
been substantiated by other studies (2–4). However, as nearly half the
patients had two separate admissions, a breakdown of length of hospital
stay for each admission in addition would have been more informative.
The duration between the two admissions and indication for the second
procedure would have also provided meaningful insight into whether the
HCR was planned or unplanned and whether there was a significant delay
between the two procedures. This is important as it has been recommended
that in HCR, both procedures should occur within 60 days of each other
and the second stage of the procedure ought to be elective (8).
The authors have also reported similar operative times in the propensity
matched comparison of the groups. Even though the operative times over
the last 2 decades have come down it is generally accepted that totally
endoscopic coronary artery bypass involves longer operative time
compared with conventional OPCAB. A similar study comparing single stage
robotically assisted HCR with conventional OPCAB showed that the
operative time in HCR was significantly longer by 2 hours(9). Another
study that evaluated the practice patterns and outcomes after HCR
reported a shorter procedural time after staged HCR than after
single-stage or concurrent HCR. Considering that nearly half the
patients in the HCR group had a 2-staged procedure the comparative
operative times would have been invaluable.
While clinically it is reassuring to note that the short- and long-term
outcomes of HCR were similar to OPCAB, the suggested economic advantage
of HCR appears a little too simplistic. The economic benefit of lesser
transfusion and shorter length of stay must be weighed against the cost
involved in carrying out two separate procedures, the requirement for
two completely different teams, and the fixed and variable costs
involved in specialized robotic equipment. A similar study comparing HCR
using robotically assisted CABG with conventional OPCAB showed that
while post-operative costs in the HCR group were lower due to shorter
lengths of stay the overall cost involved in HCR was significantly
higher due to the procedural costs (9). A more extensive analysis of the
costs involved in HCR revealed that the fixed and total overall costs
were significantly higher in HCR with a trend toward higher direct
variable costs compared to OPCAB (10). Interestingly, despite higher
costs involved with HCR, the contribution margin and the net profit with
HCR was found to be higher than OPCAB. The reason behind this paradox is
that while reimbursement for CABG is the same whether it is carried out
robotically or as a standard OPCAB, HCR draws an additional
reimbursement for PCI as a separate procedure (10). While this might be
an additional incentive for increased uptake of HCR in centers where
costs are reimbursed by insurance, it equally serves as a deterrent in
countries where healthcare is state funded.
A quarter of a century has gone by since the first reported HCR(11) and
serious efforts have been made to standardize the definitions and what
qualifies as HCR(8). Long term data showing outcomes equivalent to
conventional CABG has also been reported (12,13). However, the uptake of
HCR has remained low, comprising <1% of total CABG volumes
(6,14). The authors must be congratulated for the excellent outcome they
have achieved using the strategy of total robotic CABG and PCI, but it
is inevitable that this strategy of HCR will remain localized to few
specialized centers. Shorter length of hospital stay, lesser need for
transfusion are certainly attractive benefits of HCR but it may not be
sufficient for greater uptake. Wider adoption will only occur when the
need for HCR is clinically driven. PCI to the non-culprit LAD lesion
followed by surgical revascularization of the LAD is perhaps the most
challenging HCR strategy but may be the one that provides the
much-needed clinical impetus for increased uptake of HCR. It is also
important that more studies report strategy specific outcomes of HCR
compared to CABG and PCI to enable a better comparison of different
options.
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[Internet]. 2020 Oct [cited 2021 Mar 11]; Available from:
https://www.ahajournals.org/doi/abs/10.1161/CIRCINTERVENTIONS.120.009386