Efficacy of Single-Dose Del Nido Cardioplegia Beyond 90 Minutes in Adult Cardiac Surgery

<b>Background:</b> Del Nido (DN) cardioplegia is widely used in cardiac surgery for its efficacy in providing myocardial protection for up to 90 min with a single dose. However, its safety and efficacy during prolonged ischemia remain unclear. <b>Methods:</b> This retrospective study analyzed 471 patients who underwent cardiac surgery with CPB between January 2019 and September 2024. Patients were divided into two groups: ACC durations of 60-90 min (Group A, n = 240) and >90 min (Group B, n = 231). The perioperative characteristics, clinical outcomes, and biochemical markers were compared to evaluate the impact of prolonged ischemia. <b>Results:</b> Patients in Group B exhibited significantly higher postoperative troponin I and lactate levels at 4 h post-CPB, suggesting increased myocardial and metabolic stress. Lactate levels normalized within 24 h, indicating transient myocardial dysfunction. Defibrillation requirements and vasoactive inotropic score (VIS) were also significantly elevated in Group B, reflecting compromised myocardial electrical stability and hemodynamic challenges. However, the long-term outcomes such as mortality, LCOS, and MODS showed no significant differences between the groups. <b>Conclusions:</b> While DN cardioplegia provides sufficient myocardial protection for ACC durations within 90 min, its efficacy diminishes during prolonged ischemia, as evidenced by increased myocardial injury and hemodynamic instability. Tailored strategies, including standardized redosing protocols and enhanced perioperative management, are essential for optimizing outcomes in complex surgeries with extended ischemia times. Further prospective studies are needed to refine these protocols and assess alternative solutions for myocardial protection.