Discussion
There are essentially two forms of cardioplegia solution, depending on
the content –crystalloidcardioplegia and blood cardioplegia. The aim of
all cardioplegia methods, crystalloid-based and blood-based, is to bring
about hyperkalemic electromechanical diastolic arrest. The objective is
to provide clear vision and surgical fields without motion and to
provide optimal protection for the myocardium against ischemic injury.
We believe that there have been insufficient studies to comparedel
Nidocardioplegia, which has become increasingly used in adult cardiac
surgery in recent years, with blood cardioplegia. The present randomized
prospective study was intended to compare the biochemical parameters and
operative data for the two techniques. Our hypothesis in this study was
that conventional blood-based methods enjoy no superiority over del
Nidocardioplegia in adult patient groups.The study results indicated
that the use of anterograde single-dose DNS in isolated CABG surgery
reduced CPB and aortic cross-clamp times, yielding similar short-term
outcomes to those of a conventional multi-dose IWBC strategy, although
no statistically significant reduction was observed. Comparison of the
groups’ laboratory results showed that at xanthine oxidase measurements
were better 20 minutes after cross-clamp placement and immediately
before removal, while ADA and troponin measurements were better at
measurements after 20 min following cross-clamp removal in the DNS
group, the differences being statistically significant(p 0.023, 0.001.
0.020, and 0.032, respectively). Although better results were achieved
in the DNS group compared to theIWBC group at other tests, no
statistically significant difference was determined. Consistent with the
limited number of previous observational studies, our results suggest
that del Nidocardioplegia can be safely used in CABG surgery.
Some authors have suggested that the ischemic period and CPB times may
be shorter with DNS because this is applied in a single dose, and no
additional doses are required for 90 minutes (7).The present research
does not allow us to draw any definite conclusion regarding the best
timing strategies for additional doses of DNS in CABG surgery. In fact,
no consensus exists concerning timings for repetition of DNS. A single
dose of DNS is generally sufficient in patients undergoing CABG, and no
interruption occurs during surgery. The mean cross-clamp time in the
other group was 48.36 ± 17.26 minutes, indicating thatcardioplegiawas
administered twice on average in each patient. We applied topical
hypothermia in all cases in line with our clinical myocardial protection
routine. Topical cooling may be beneficial, although some authors have
reported no benefit (8).We did not find a significant difference between
the two cardioplegia strategies in terms of myocardial injury. XOD,ADA,
SOD,PON, arylesterase, native thiol, total thiol, thiol disulfide,
troponin-I, and CK-MB levels were similar between the two
groups.However, in the DNS group, XOD results were significantly better
20 min after cross-clamp installation and before removal of the
cross-clamp, and ADA and troponin and measurements later than 20 minutes
following cross-clamp removal.Consistent with the present study, Yongnan
Li et al.’s meta-analysis showedno statistically significant difference
between troponin-I, troponin-T, and CK-MB levels in 836 patients (9).
The risk of myocardial dysfunction associated with higher levels of
intracellular calcium is greater in older heart surgery patients than in
younger individuals (10).DNS has a lower calcium content than standard
blood cardioplegia. One recent rat study showedlower intracellular
calcium levels in the ischemic period wıth DNS than with blood
cardioplegia (11).As discussed in previous studies, DNS may represent an
excellent alternative to conventional techniques in adult cardiac
surgery, irrespective of whether patients are low-risk or high-risk
(12).The findings of the present study revealed no difference between
the two groups in terms ofclinical outcomes including short-term
mortality, intensive care unit stay, orinotropic agent requirement.
Another advantage in terms of topical coldness is that the crystalloid
in the DNS has a ratio of 4:1, and the content is at a temperature of
4°C, compared to 32°C for IWBC, which is prepared using warm blood from
the CPB circulation. A single dose of cardioplegia was employed in
almost all the DNS cases. The single dose of cardioplegia results in
less cardioplegia volume and in less hemodilution.