Limitations
This is an observational single center retrospective study which makes it susceptible to inherent selection and information biases. However, the prospective nature of the data collection and the very low rate of missing data add strength to the internal validity of the study. Likewise, since all procedures were performed by a single surgeon, bias from difference in surgical and myocardial protection techniques is minimized. Importantly, the findings from our study must be interpreted and compared to previous and future studies in the context of the large heterogeneity in cardioplegia practice with regard to composition, temperature, additives and adjuncts for myocardial protection. These factors are important confounders that must be evaluated when comparing different studies of cardioplegia. Finally, we reported only short-term outcomes and weather DNC is associated with any potential long-term benefits is unknown.