Protecting the aged heart during cardiac surgery: Use of del Nido cardioplegia provides superior functional recovery in isolated hearts

Objectives: Aged hearts are particularly vulnerable to ischemia-reperfusion injury. Our objective was to determine if del Nido cardioplegia, which contains lidocaine, less blood, and less calcium than our standard cardioplegia, provides superior protection for aged hearts. We also sought to determine if the lidocaine in del Nido cardioplegia is adequate to prevent Na⁺ influx via the window current. Methods: Sodium channel kinetics were measured in rat cardiomyocytes with and without lidocaine. Recovery after 60 minutes of cardioplegic arrest was assessed in isolated working senescent rat hearts. Del Nido cardioplegia was delivered as a single dose (n = 8) because it is used clinically, and standard cardioplegia was delivered as an induction dose with re-dosing every 20 minutes (n = 8). After 20 minutes of reperfusion, hearts were switched to working mode for 60 minutes. Flows were indexed to ventricular dry weight. Troponin release was assayed. Results: Sodium channel kinetics indicated that the lidocaine concentration in del Nido cardioplegia minimizes the potential for Na+ influx via the window current. Spontaneous contractions occurred in fewer hearts arrested with del Nido cardioplegia (88% vs 13%; P =.01), and troponin release was reduced (0.24 vs 0.89 ng/mL; P =.017). Cardiac output was approximately 90% of baseline in the del Nido group compared with approximately 50% in the standard group (173 ± 14 vs 86 ± 22 mL · min^-1 · g^-1; P =.0008). Stroke work was higher in the del Nido group (93 ± 6 vs 41 ± 10 mL · mm Hg · g^-1; P =.0002). Conclusions: Del Nido cardioplegia prevents spontaneous contractions during arrest, reduces troponin release, and results in superior myocardial function in isolated aged hearts. Del Nido cardioplegia has the potential to provide superior myocardial protection for older patients undergoing cardiac surgery.