Outcomes of Del Nido and hyperkalemic blood cardioplegia in adult cardiac surgery with prolonged aortic cross-clamp times

Background: The utility and uptake of Del Nido cardioplegia in adult cardiac surgery is rapidly increasing. Cases with prolonged aortic cross-clamp times necessitate multi-dosing however an understanding of safe ischaemic times and definitive guidelines in this domain are lacking. Therefore, this study aimed to assess the safety and efficacy of our DNC strategy by comparing post-operative troponin profiles and clinical outcomes between Del Nido and hyperkalaemic cardioplegia for cases with aortic cross-clamp times of greater than 90 min. Methods: A single-centre, retrospective cohort study at Flinders Medical Centre and Flinders Private Hospital of patients undergoing composite cardiac surgery with a cross-clamp time longer than 90 min. Data was prospectively collected from the Flinders Cardiac Surgery Registry from June 2014 to December 2022. A propensity-matched (1:1) analysis was performed comparing patients receiving Del Nido cardioplegia (n = 194) to those receiving hyperkalemic blood cardioplegia (n = 194). The primary outcome was the postoperative troponin release profile with clinical events reported as secondary outcomes. Results: There was no difference in the peak or median troponin at 6, 12 and 72 h nor the number of patients with positive troponin profiles postoperatively between cohorts. There was no difference in clinical outcomes between groups with aortic cross-clamp times of 90 min which remained true in sensitivity analysis extending out to 120 min. The Del Nido cohort received less cardioplegia volume (p < 0.001) and were more likely to return to spontaneous rhythm (p < 0.002). Conclusion: Del Nido cardioplegia for anticipated aortic cross-clamp times of greater than 90 min provided equivocal post-operative troponin profiles and clinical outcomes compared to multidose hyperkalemic blood cardioplegia.