Myocardial Protection during Cardiac Surgery: Warm Blood versus Crystalloid Cardioplegia

Purpose: Prevention of myocardial injury is essential during cardiac surgery. Both crystalloid and blood cardioplegia are popular methods for myocardial protection. Most experimental studies have been in favor of blood cardioplegia. The objective of this study is to determine whether the use of warm blood cardioplegia (BCP) is superior to crystalloid cardioplegia (CCP) by means of myocardial injury markers and clinical outcome parameters. Materials and Methods: In a consecutive series of 293 patients, the first 150 received crystalloid cardioplegia, whereas the next 143 patients received blood cardioplegia. Postoperative myocardial injury was assessed by CTnI and CK-MB. Perioperative morbidity and mortality and clinical outcome parameters (need for inotropic support, ICU and hospital stay) were recorded. An unpaired student t-test was performed to analyse continuous postoperative variables relating to myocardial damage. The presence of possible confounders influencing the CTnI or CK-MB concentrations was tested using a student t-test for continuous variables, for categorical variables ANOVA was used. A final longitudinal model was created for CTnI and CK-MB. CTnI was analyzed by a mixed model with random intercept and slope. For all tests performed, statistical significance was 5%. Results: Both groups were well matched with respect to preoperative variables. No significant difference could be found in maximum postoperative levels of CTnI (8.8 ± 18.4 μg/l in BCP vs 9.6 ± 16.5 μg/l in CCP, p = 0.6455) or CK-MB (19.2 ± 31.0 μg/l in BCP vs 26.4 ± 41.5 μg/l in CCP, p = 0.1209). Nor was there any significant difference in other postoperative variables. Testing treatment effect over time proved only significant influence of the surgical intervention type on CTnI levels in time (p