Buckberg vs. Del Nido in Isolated Aortic Valve Replacement: A Prospective, Two-Center, Randomized Trial

Cardioplegia plays a fundamental role in myocardial protection during cardiac surgery requiring heart arrest. Traditionally, the Buckberg solution (BS) has been the standard choice, but increasing interest in the Del Nido solution (DNS) has prompted further research into its effectiveness in adult cardiac procedures. Originally developed for pediatric cardiac surgery, DNS has gained traction in adult patients due to its single-dose administration, reducing the need for frequent redosing during surgery.

This prospective, two-center, randomized trial aimed to compare the efficacy of BS and DNS in isolated aortic valve replacement (AVR). Conducted between July 2019 and August 2023, the study enrolled 311 adult patients undergoing first-time isolated AVR. Patients were randomized into two groups: 159 receiving BS and 152 receiving DNS. The study’s primary endpoint was to assess postoperative myocardial injury through creatine kinase (CK) and ultrasensitive troponin T (TnT) levels. Secondary endpoints included cardiopulmonary bypass (CPB) and cross-clamp times, rhythm recovery, intraoperative glucose levels, insulin administration, and overall surgical workflow.

Key Findings:

1. Cardioplegia Volume:
   • The total cardioplegia volume was significantly higher in the DNS group (1000ml vs. 374.5ml in the BS group, p<0.001).
   • This raised concerns about hemodilution; however, no significant differences were found in red blood cell transfusion rates.
2. Myocardial Injury Biomarkers:
   • Postoperative CK levels were similar between groups (430 U/L in the BS group vs. 414.5 U/L in the DNS group, p=0.886).
   • TnT levels also showed no significant difference (284 ng/L vs. 258 ng/L, p=0.255).
3. Rhythm Recovery & Defibrillation:
   • DNS was associated with a higher rate of spontaneous rhythm return after cross-clamp removal (66.7% vs. 43.1% in the BS group, p<0.001).
   • Fewer patients in the DNS group experienced ventricular fibrillation requiring defibrillation (23.6% vs. 49.7%, p<0.001).
4. Glycemic Control:
   • Intraoperative peak glucose levels were significantly lower in the DNS group (128 mg/dL vs. 198 mg/dL in the BS group, p<0.001).
   • Insulin administration was required in 51% of BS patients compared to only 18.1% in DNS patients (p<0.001).
5. Surgical Workflow Benefits:
   • DNS required fewer interruptions for re-dosing, making the surgical workflow more efficient.
   • BS required redosing every 15–20 minutes, while DNS was administered as a single dose (with optional additional dosing beyond 90 minutes).

Clinical Implications:

The study concludes that both cardioplegia solutions provide equivalent myocardial protection, as evidenced by similar postoperative CK and TnT levels. However, DNS presents several intraoperative advantages: improved glycemic control, better rhythm recovery, fewer defibrillation requirements, and a more efficient surgical workflow due to fewer interruptions. These benefits may make DNS particularly attractive for minimally invasive AVR procedures where reducing CPB time is crucial.

While the higher cardioplegia volume in DNS raised concerns about hemodilution, no clinically significant effects were observed in hematocrit levels or transfusion requirements. Similarly, renal function outcomes were comparable between groups.

Study Limitations:

1. Blinding: Due to differences in cardioplegia administration protocols, intraoperative personnel were not blinded to treatment allocation.
2. Multiple Secondary Endpoints: The inclusion of multiple secondary outcomes increases the risk of statistical errors, requiring cautious interpretation.
3. Center-Specific Practices: Differences in perioperative management protocols between the two participating hospitals could have influenced the results.

Conclusion:

Del Nido cardioplegia is a safe and effective alternative to Buckberg cardioplegia for isolated AVR, offering comparable myocardial protection while providing advantages in glycemic control, rhythm recovery, and surgical efficiency. These benefits could make DNS the preferred choice in select adult cardiac procedures, though further research may be needed to explore its long-term impact on clinical outcomes.

Study Ranking = 5 (Highest Quality) This study ranks as a 5 due to its large sample size, randomized controlled design, multicenter collaboration, and adherence to CONSORT guidelines, making it a robust and scientifically valuable contribution to cardiac surgery research.