M . Szpytma et al .: J Extra Corpor Technol 2024 , 56 , 149 – 158 153
Table 3 . Intraoperative variables for aortic cross-clamp time greater than 90 min .
Variable |
HKB |
DNC |
p-value |
N |
194 |
194 |
|
Procedure type CABG |
30 ( 15 %) |
24 ( 12 %) |
0.72 |
Aortic / Dissection |
17 ( 9 %) |
21 ( 11 %) |
|
Other |
10 ( 5 %) |
14 ( 7 %) |
|
Valve |
90 ( 46 %) |
93 ( 48 %) |
|
Valve / CABG |
47 ( 24 %) |
42 ( 22 %) |
|
CPB time ( min ) |
145 ( 125 , 169 ) |
143 ( 128 , 171 ) |
0.98 |
AXC time ( min ) |
114 ( 102 , 132 ) |
112 ( 102 , 129 ) |
0.45 |
Total procedure time ( min ) |
269 ( 229 , 307 ) |
266 ( 232 , 320 ) |
0.76 |
Hemofiltration requirement |
7 ( 4 %) |
6 ( 3 %) |
1.00 |
Urine output ( mL ) |
400 ( 220 , 700 ) |
400 ( 200 , 750 ) |
0.99 |
Minimum haemoglobin ( g / L ) |
95 ( 81 , 106 ) |
90 ( 76 , 103 ) |
0.027 |
Minimum cardioplegia temperature (° C ) |
31 ( 30 , 31 ) |
5 ( 5 , 6 ) |
< 0.001 |
Total cardioplegia volume delivered ( mL ) |
1885 ( 1550 , 2249 ) |
1009 ( 1004 , 1381 ) |
< 0.001 |
Cardioplegia delivery route Antegrade |
70 ( 36 %) |
146 ( 75 %) |
< 0.001 |
Retrograde |
0 ( 0 %) |
2 ( 1 %) |
|
Antegrade + Retrograde |
124 ( 64 %) |
44 ( 23 %) |
|
Number of cardioplegia doses |
6 ( 5 , 7 ) |
1 ( 1 , 2 ) |
< 0.001 |
Spontaneous recovery of rhythm |
115 ( 59 %) |
170 ( 89 %) |
< 0.001 |
Maximum ischemic time ( min ) |
32 ( 28 , 36 ) |
98 ( 90 , 109 ) |
< 0.001 |
Peak creatinine on pump ( umol / L ) |
99 ( 82 , 126 ) |
101 ( 82 , 134 ) |
0.47 |
Last haemoglobin on pump ( g / L ) |
96 ( 83 , 108 ) |
96 ( 86 , 107 ) |
0.80 |
Continuous variables are expressed median ( IQR ), categorical variables are expressed number (%). Abbreviation : Abbreviation : HKB – hyperkalaemic blood cardioplegia ; DNC – Del Nido cardioplegia ; CABG coronary artery bypass graft ; CPB – cardiopulmonary bypass ; AXC
Table 4 . Post-operative variables for aortic cross-clamp time greater than 90 min .
Characteristic |
HKB |
DNC |
p-value |
N |
194 |
194 |
|
Mechanical ventilation ( h ) |
17 ( 8 , 25 ) |
18 ( 8 , 27 ) |
0.91 |
ICU stay ( h ) |
69 ( 43 , 137 ) |
70 ( 27 , 120 ) |
0.60 |
Hospital stay ( day ) |
9 ( 7 , 13 ) |
10 ( 7 , 14 ) |
0.094 |
Mortality within 30 days |
3 ( 2 %) |
8 ( 4 %) |
0.22 |
In hospital mortality |
3 ( 2 %) |
8 ( 4 %) |
0.22 |
Return to theatre |
3 ( 2 %) |
12 ( 6 %) |
0.017 |
Stroke |
5 ( 3 %) |
4 ( 2 %) |
1.00 |
AKI |
34 ( 18 %) |
39 ( 20 %) |
0.52 |
PRBC |
72 ( 37 %) |
75 ( 39 %) |
0.69 |
MI |
17 ( 9 %) |
15 ( 8 %) |
0.85 |
IABP |
17 ( 9 %) |
10 ( 5 %) |
0.23 |
Continuous variables are expressed median ( IQR ), categorical variables are expressed number (%). Abbreviations : HKB ; hyperkalemic blood cardioplegia ; DNC – Del Nido cardioplegia ; ICCU – Intensive Critical Care Unit ; AKI – acute kidney injury ; PRBC – Any red blood cell transfusion ; MI – myocardial infarction ; IABP – intra-aortic balloon pump
neous activity , with no significant differences in clinical outcomes ( Table 4 ). While there was overall equivalence in myocardial injury as inference by post-operative troponin T release ( Tables 5 and 6 ) the optimal timing for DNC re-dosing and clinical endpoints for equivalence remain unclear . Sensitivity analysis of patients with cross-clamp times of greater than 120 min similarly demonstrated no significant differences in clinical outcomes ( Table 8 ), however troponin results were equivocal ( Tables 6 and 9 ).
Troponin profile
The post-operative release of high-sensitivity troponin T is one measure reflecting the efficacy of myocardial protection and was chosen for this study due to its lower false positive rate compared to other biomarkers such as CKMB . Recent meta-analyses reporting troponin release in the setting of DNC are of limited value and provide little guidance on strategies for cases with extended AXC times [ 22 , 23 ]. In reporting the troponin T profile for DNC out to 72 h we found equivalence in the median timepoint values and area under the curve between propensity-matched groups in our primary analysis . This is in keeping with the initial single dose experience from our unit suggesting a robustness in the safety profile of our cardioplegia protocol despite DNC having threefold longer ischemic times ( 98 min vs . 32 min ) [ 17 ] and the recent report by Willekes et al . [ 18 ] where they reported similar findings for patients with extended AXC times . The sensitivity analysis highlights the variation in redosing within this early experience with 25 % of patients in the sub-study receiving a single dose of DNC . In this cohort although troponin T profile values within 72 h were not equivalent , equivalence was observed in the incidence of positive troponin T at 72 h . With further ongoing evaluation , the benefit of DNC may be ascertained .
The literature supporting multi-dose DNC is evolving , with reports in early studies of multi-dose DNC showing no