Del Nido cardioplegia (DNC), initially designed for pediatric cardiac surgery, is increasingly adopted for adult cardiac surgeries due to its extended myocardial protection capabilities. In surgeries requiring prolonged aortic cross-clamp (AXC) times, which exceed 90 minutes, the efficacy and safety of DNC compared to hyperkalemic blood cardioplegia (HKB) remain under scrutiny. This study evaluates the clinical outcomes and myocardial protection provided by both strategies in adult patients undergoing complex cardiac procedures.
This retrospective cohort analysis included 388 propensity-matched patients (194 DNC and 194 HKB recipients) with AXC times exceeding 90 minutes. Data were gathered from two institutions between 2014 and 2022. Outcomes assessed included postoperative troponin profiles, rates of myocardial infarction (MI), acute kidney injury (AKI), stroke, return to surgery, and other complications. Sensitivity analyses extended comparisons to cases with AXC times greater than 120 minutes.
Key Findings
Myocardial Protection
Troponin profiles, a biomarker for myocardial injury, served as the primary metric for assessing myocardial protection. Across 6, 12, and 72-hour postoperative intervals, no significant differences in median troponin levels were observed between the two groups for AXC times exceeding 90 minutes. These findings indicated equivalent myocardial protection. Sensitivity analysis for AXC times beyond 120 minutes suggested higher peak troponin levels in the DNC group but did not translate into clinically significant outcomes.
Efficiency and Logistical Benefits
DNC demonstrated notable procedural advantages. Patients in the DNC group required fewer cardioplegia doses, with longer intervals between redosing (approximately 90 minutes compared to HKB’s 30 minutes). Consequently, the DNC protocol reduced overall cardioplegia volume and procedural interruptions. The study also noted higher rates of spontaneous rhythm recovery in the DNC group (89% vs. 59% for HKB), potentially attributable to DNC’s lidocaine-mediated sodium channel inhibition.
Clinical Outcomes
Clinical endpoints, including mortality, MI, AKI, stroke, and return to surgery, showed no significant differences between DNC and HKB groups. These outcomes remained consistent even in cases with AXC times exceeding 120 minutes. However, the DNC cohort exhibited a slightly higher rate of return to surgery for bleeding complications (6% vs. 2% in the HKB group). Despite this, both groups demonstrated comparable ICU stays, mechanical ventilation durations, and hospital lengths of stay.
Discussion
The comparable myocardial protection offered by DNC and HKB highlights DNC’s suitability for adult cardiac surgeries, particularly for complex cases with prolonged ischemic intervals. DNC’s procedural benefits, such as reduced dosing frequency and improved rhythm recovery, align with its clinical utility and growing adoption. These attributes support its use in extended AXC scenarios without compromising patient safety.
Troponin Analysis
The absence of significant differences in troponin release profiles at early (6 and 12 hours) and late (72 hours) intervals underscores DNC’s efficacy in myocardial preservation. Notably, previous studies on pediatric populations reported similar findings, suggesting that DNC’s extended ischemic protection translates well to adult settings.
Procedural Considerations
DNC’s advantages, including less frequent redosing and improved rhythm recovery, reflect its composition. Its lidocaine component inhibits sodium channels, reducing arrhythmias, while magnesium prevents calcium influx, mitigating myocardial stress. These characteristics make DNC a practical choice for reducing procedural complexity in surgeries with extended ischemic times.
Limitations
This study has inherent limitations due to its retrospective design. Variability in procedural protocols, surgeon preferences, and redosing strategies could introduce bias. Additionally, the lack of long-term follow-up data limits the ability to evaluate extended postoperative outcomes. Further, the exclusion of certain metrics, such as 24-hour troponin levels, cardiac output measures, and detailed arrhythmia profiles, narrows the scope of myocardial assessment. Prospective, randomized trials are necessary to establish standardized dosing regimens and evaluate DNC’s broader applicability.
Conclusion
This study affirms the safety and efficacy of DNC for adult cardiac surgeries requiring prolonged AXC times. Its procedural advantages, including reduced dosing and superior rhythm recovery, make it a compelling alternative to HKB. While troponin profiles and clinical outcomes were largely equivalent, DNC’s logistical benefits could streamline complex surgeries. Future research should aim to standardize multi-dose protocols and explore long-term clinical impacts to further validate DNC’s role in adult cardiac surgery.
