M . Szpytma et al .: J Extra Corpor Technol 2024 , 56 , 149 – 158 151
Figure 1 . Consort diagram . The 178 patients either had both DNC and HPK cardioplegia ( 55 cases ) or were excluded as the surgeons performing operations did not use both cardioplegic techniques ( 112 cases ). Abbreviations : DNC – Del Nido cardioplegia , HKB – hyperkalemic blood cardioplegia .
on the method described by Lakens using the Two One-Sided Tests ( TOST ) procedure [ 4 ]. Continuous troponin values underwent log transformation to approximate normality . The TOST procedure utilised the Fishers exact Z-test for proportions . With upper and lower equivalence boundaries defined as Cohen ’ s d ± 0.3 , to detect a type I error rate of 0.05 we had a power of 95 % for myocardial infarction and 80 % for peak postoperative troponin value between primary analysis groups .
Results Patient characteristics
Five thousand and ninety-four adult cardiac cases were performed between 12.6.2014 and 31.12.2022 , with 845 having an AXC ( aortic cross-clamp ) time of greater than 90 min . Six hundred and fifty-seven patients were eligible for inclusion in propensity analyses ( see consort diagram in Figure 1 ), resulting in 194 patients in each group for AXC time > 90 min , and
64 patients in each group for the > 120 min AXC time , with both cohorts demonstrating similar pre-operative characteristics respectively ( Tables 1 and 2 ). Primary analysis
Seventy percent of cases in both groups were valve replacement or valve / coronary grafting surgery . There was no significant difference in total AXC time between the two groups . DNC was delivered at a colder temperature , requiring less volume and fewer doses of cardioplegia . Patients receiving HKB were more likely to receive combined antegrade and retrograde cardioplegia delivery . The maximum period of ischemia was significantly greater for DNC compared with HKB ( 98 ( 90 , 109 ) vs . 32 ( 28 , 36 ) p < 0.001 ) and the spontaneous return of rhythm was more likely with the DNC compared to HKB ( 89 % vs . 59 %, p < 0.001 )( Table 3 ).
Clinical outcomes were the same between DNC and HKB for rates of post-operative intra-aortic balloon pump ( IABP ), myocardial infarction , acute kidney injury , stroke , return to