Page 22 - ANZCP GAZETTE DECEMBER 2023

A RETROSPECTIVE COHORT STUDY COMPARING THE EFFECT OF DEL NIDO AND MICROPLEGIA CARDIOPLEGIA SOLUTIONS ON AORTIC CROSS CLAMP TIMES IN CORONARY ARTERY BYPASS SURGERY
Abstract
Background: The use of single dose del Nido cardioplegia in adult cardiac surgery is increasing worldwide, primarily due to the decreased requirement for re- dosing. This study aimed to retrospectively compare the differences in the aortic cross clamp and bypass times in patients undergoing coronary artery bypass graft surgery (CABG) using del Nido cardioplegia solution versus multidose microplegia. The clinical outcome change in haemoglobin and time spent in ICU were used to evaluate the efficacy of the cardioplegia solution.
Methods: Retrospective data was collected from Waikato District Health Board records over a two-year period (2019 to 2020). 204 patients undergoing isolated coronary artery bypass graft surgery receiving del Nido cardioplegia or microplegia were included. High risk patients with a EURO score >6 were excluded. Pre- operative, intraoperative and postoperative data was collected. Parameters measured included the Aortic cross-clamp and Cardiopulmonary bypass (CPB) times, the first, last and lowest haemoglobin and length of ICU stay. The parameters for the two groups were compared.
Results: The aortic cross clamp time was significantly lower in the patients who received del Nido cardioplegia (64.24 ± 23.56 vs 82.60 ± 53.66, p= 0.001). The CPB time (90.46 ± 27.9 vs 103.53 ± 33.20, p= 0.182) and time spent in ICU (28.50 ± 20.33 vs 29.11 ± 21.31, p= 0.837) was also lower in the del Nido group this however, did not reach statistical significance. Both groups had similar clinical outcomes in terms of change in hemoglobin.
Conclusion: The use of del Nido cardioplegia in coronary artery bypass graft surgery resulted in reduced cross clamp times. The short-term clinical outcomes of patients receiving del Nido cardioplegia were comparable to those receiving multidose cardioplegia.
Introduction:
Adult cardiac surgery is routinely performed on an arrested heart facilitating a motionless and bloodless field(1). Cardioplegia is used to rapidly induce and maintain electrically quiescent heart, decreasing its metabolic requirements and preserving myocardial function. There are several cardioplegia techniques and the current literature is yet to determine a superior solution (2-3). Myocardial protection is essential to prevent ischemic injury and thus morbidly and mortality in patients (4-5)
Both del Nido and microplegia utilise a hyperkalemic arrest. Microplegia was the principal cardioplegia used in our unit until 2019. It is a blood based cardioplegia that is combined with K, Mg and aspartate and delivered via a syringe pump driver at intermittent intervals. It provides a physiologic environment that offers maximal oxygen and substrate delivery (6). In comparison, del Nido is a single- dose crystalloid-based solution (1:4 blood: crystalloid) delivered via a cardioplegia delivery system. Lidocaine is the hallmark of del Nido as it inhibits calcium flux by interfering with the activation of the Na-Ca exchanger. This is beneficial for preventing calcium overload in the myocardium during the ischemia/ reperfusion period (1,3 6-7).
Del Nido cardioplegia has an extended arrest time of 90 minutes which decreases the number of disruptions to the surgeon compared to microplegia. The single-dose approach with del Nido can potentially reduce clamp times and improve postoperative outcomes. However, this is at the detriment of an increased crystalloid load, increasing the degree of haemodilution and decreasing haematocrit (7,9).
The primary objective of this study was to evaluate the impact of different cardioplegia solutions on the aortic cross-clamp and bypass times in CABG surgery. The secondary objectives of this study were to examine the efficacy of del Nido and microplegia using the clinical outcomes change in Hb and length of ICU stay.
Courtney Adams, Waikato District Health Board
19 DECEMBER 2023 | www.anzcp.org