Discussion
This retrospective, single-center study of early and long-term results
of CABG in dialysis-dependent end-stage renal disease patients showed
satisfactory early mortality results with no increased operative or DSWI
risk with BITA grafting. The long-term results were also better in the
BITA group.
BITA grafting did not increase the overall operative mortality. Our
safety-focused operative strategy and postoperative management likely
led to successful early results. To ensure patient safety, we minimized
operative invasiveness. In patients with impaired heart function, severe
left main trunk disease, or preoperative hemodynamic instability, we
inserted an IABP preoperatively. We did not hesitate to insert an IABP
intraoperatively or switch to on-pump surgery when patients became
hemodynamically unstable during the operation. Moreover, we focused on
postoperative fluid management and avoided postoperative intravascular
dehydration to reduce the risk of non-occlusive mesenteric ischemia
(NOMI). Hypovolemic shock, cardiogenic shock, and administration of
alpha-adrenergic drugs were the most significant postoperative risk
factors for NOMI17,18. Patients’ body weight was
gradually adjusted to reach their preoperative dry weight at around the
end of the first postoperative week.
Previous studies reported that BITA grafting was a risk factor for
DSWI19-21, however, we found no differences in the
frequency of DSWI between the groups. Our patients’ ITAs were harvested
by skilled surgeons using the skeletonization technique with a harmonic
scalpel, which reduces the risk of DSWI22.
The long-term results showed superior MACE-free rates and less
cardiac-related death in the BITA group. The BITA group showed a clear
trend towards improved survival, although there was no significant
difference. This might partly be because of a short follow-up period and
small number of patients. Another cause might be the characteristics of
dialysis patients, who are immunocompromised and exhibit accelerated
atherosclerotic and arteriosclerotic changes23,24.
Therefore, they are at a higher risk for non-cardiac comorbidities such
as infection, stroke, and organ impairment. However, BITA grafting could
have contributed to preventing cardiac-related events.
Currently, there is no consensus on the efficacy of BITA grafting in
dialysis patients currently exists15. The limited
number of studies on CABG in dialysis patients are mostly from Japan.
BITA grafting leads to significantly fewer cardiac-related events, but
not superior overall survival, when compared to SITA
grafting25. BITA grafting also may lead to reduced
MACE in DM patients, although no significant difference was observed in
the overall cohort17. Although most patients in our
study underwent off-pump CABG, previous studies included both on-pump
and off-pump procedures. This reflects changing surgical trends in
Japan, where surgeons have switched from on-pump to off-pump CABG
between the late 1990s and early 2000s, during which time the off-pump
technique evolved25,26. Propensity-matched analysis of
off-pump CABG in hemodialysis patients was reported in 2018, which
better reflected contemporary practices in Japan. Here, BITA grafting
had no advantages for mid-term overall survival, freedom from cardiac
death, or from cardiac events 15.
BITA grafting achieved a significantly better MACE-free rate and
resulted in significantly fewer cardiac deaths. Though not significantly
different, the BITA group showed superior 5-year overall survival rates
over those of the SITA group. This may be because GEA use (in 4.2% of
patients) in the SITA group was less common than in previous reports
(22.3% in Nakahara et al.’s study) 15. Multiple
arterial grafting offers some survival benefit over single arterial
grafting27,28. Although we tried to use GEAs, they are
often calcified and ungraftable in dialysis patients, and are prone to
flow competition with the native coronary artery29.
Therefore, to improve the patency of SVGs, we started no-touch
harvesting in 2019, whose long-term patency is equal to
ITAs30,31. Future analyses should clarify the efficacy
of no-touch SVGs compared to GEA grafts.
Multivariate analysis revealed that age and incomplete revascularization
significantly predicted remote death. Incomplete revascularization
during off-pump CABG was an independent predictor of cardiac death,
which was more pronounced in patients with impaired heart
function32. In cases with difficult complete surgical
revascularization, hybrid revascularization involving CABG and
percutaneous coronary intervention should be considered to minimize
perioperative risk and prevent remote cardiac death.
There are several limitations to this study. First, this was a
single-center, non-randomized, retrospective, and observational study.
Second, the number of patients was relatively small; no definitive
conclusions could be reached. Third, the follow-up period was relatively
short.