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.