How should Del Nido cardioplegia be prepared, dosed, and what are its contraindications for a 70‑kg adult undergoing cardiac surgery?

Del Nido Cardioplegia in Adult Cardiac Surgery

Del Nido cardioplegia can be safely used in adult cardiac surgery as a single-dose solution for procedures with aortic cross-clamp times up to 90 minutes, but requires redosing at 60-90 minute intervals for longer procedures to prevent increased myocardial injury. 1

Composition and Preparation

Del Nido cardioplegia is a crystalloid-based solution mixed with blood in a 4:1 ratio (4 parts crystalloid to 1 part blood), which is the inverse of conventional blood cardioplegia 1. The solution contains lidocaine to prolong hyperpolarization and prevent intracellular calcium overload 1, 2.

For a 70-kg adult, the typical initial dose is approximately 1 liter delivered over several minutes at a pressure of 60-100 mmHg when given antegradely into the aortic root 1.

Alternative Base Solutions

While Plasma-Lyte A is the original base solution, normal saline, Ringer's lactate, and plain Ringer's provide comparable myocardial protection when Plasma-Lyte A is unavailable 3.

Dosing Strategy

Initial Dose

• Single bolus of approximately 1 liter delivered antegradely into the aortic root at 60-100 mmHg pressure 1
• Cardiac arrest typically occurs within 30-60 seconds (faster than retrograde delivery) 1

Redosing Protocol

The evidence strongly supports a structured redosing approach:

• For cross-clamp times <90 minutes: Single dose is adequate 1, 4
• For cross-clamp times 90-120 minutes: Redose at 60-90 minutes 4, 5
• For cross-clamp times >120 minutes: Second redose should occur before 70 minutes after the second infusion 5

Critical threshold: Avoid exceeding 70 minutes between the second and third infusions, as this correlates with significantly elevated troponin levels and increased vasoactive support requirements 5.

Clinical Outcomes and Evidence Quality

The 2019 EACTS/EACTA/EBCP guidelines note that evidence supporting del Nido in high-risk operations with prolonged ischemia is insufficient, with meta-analysis of 1,501 patients showing no mortality reduction (RD 0,95% CI 0.01 to 0.01; P=0.53) or difference in myocardial enzyme release compared to conventional cardioplegia 1.

However, del Nido offers practical advantages:

• Shorter cardiopulmonary bypass times due to fewer interruptions for redosing 6, 7
• More frequent return to spontaneous rhythm (52% vs 27%) 6
• Reduced defibrillation requirements due to lidocaine's antiarrhythmic effects 2, 6

Important Caveat for Prolonged Ischemia

In aortic root surgery with cross-clamp times >180 minutes, del Nido was associated with higher CK-MB levels (75.1 vs 60.5 μg/L, P=0.01) compared to blood cardioplegia 6. A 2025 meta-analysis confirmed comparable early mortality but noted lower troponin T levels with del Nido (SMD -0.22, P=0.049) 8.

Contraindications and High-Risk Scenarios

Exercise caution or avoid del Nido in:

• Complex procedures requiring cross-clamp times >180 minutes without planned redosing 6
• Severe coronary artery disease with poorly developed collaterals (limits cardioplegia distribution) 1, 9
• Significant aortic insufficiency (prevents adequate antegrade delivery) 1, 9

In these scenarios, consider conventional blood cardioplegia or combined antegrade-retrograde delivery 1.

Preferred Patient Populations

The 2019 and 2024 guidelines recommend blood cardioplegia solutions (including del Nido) should be considered in selected patients to reduce hemodilution, bleeding, and transfusion requirements (Class IIa, Level B) 1, 10. This specifically applies to:

• Patients with anemia
• Low body surface area
• Chronic kidney disease
• Complex procedures 1, 10

Practical Implementation

Delivery method: Antegrade via aortic root proximal to cross-clamp at 60-100 mmHg, or directly into coronary ostia with pressure monitoring 1

Temperature: Administered cold to maintain hypothermia and cardiac arrest 1

Monitoring: The 2024 guidelines recommend routine assessment of RV and LV function by transesophageal echocardiography pre- and post-CPB for immediate quality control of myocardial protection (Class I, Level B) 10. Review cardiac enzyme release within 24 hours postoperatively 10.

Key Algorithmic Decision Points

1. Is cross-clamp time expected to be <90 minutes AND no severe CAD/AI present? → Single-dose del Nido is appropriate
2. Is cross-clamp time 90-120 minutes? → Plan redose at 60-90 minutes
3. Is cross-clamp time >120 minutes? → Redose at 60-90 minutes, then again before 70 minutes after second dose
4. Is cross-clamp time >180 minutes with complex anatomy? → Consider conventional blood cardioplegia instead

The 2019 guidelines emphasize that myocardial protection strategies should be patient-centered and tailored based on clinical condition and procedural complexity rather than relying on a fixed institutional solution (Class I, Level C) 1.