Cardioplegia, CPD Cardioplegia, Blood Cardioplegia, Microplegia, Micro Cardioplegia, Myocardial Protection, Myocardial Protection Cardioplegia - Adenocaine and the Thermacor 1200 from Smisson-Cartledge Biomedical
Medical Research Article
Warm non-depolarising adeonsine and lidocaine cardioplegia: continuous versus intermittent delivery
Please contact us for more information
Dept Physiology and Pharmacology
Molecular
James
Townsville
Key Words: warm cardioplegia, normothermia, organ preservation, heart, adenosine, lidocaine, myocardium, ischemia, cardiac surgery
Abstract:
Objective: Continuous infusion of warm to normothermic cardioplegia limits the surgeon’s visual field, increases coronary vascular resistance and can lead to potassium-exacerbated ischemia-reperfusion damage. Our aim was to examine the versatility of a new normokalemic, non-depolarising adenosine-lidocaine (AL) cardioplegia during continuous or intermittent infusion at 33°C, and compare it with Lidocaine (lido) cardioplegia after 60 min arrest.
Methods: Isolated-perfused rat hearts were arrested at 33°C for 40 or 60 min with 200 ?M adenosine and 500 ?M lidocaine in Krebs-Henseleit buffer (10 mM glucose, pH 7.6-7.7 @ 37 °C) or 500 ?M lidocaine in Krebs-Henseleit buffer delivered at 60 mmHg.
Results: Times to arrest were 7 to 10 sec for the AL groups, and 102 ± 27 sec for the lido group (P<0.05). Total cardioplegia volumes for intermittent (2 min every 18 min) and continuous deliveries were 122-160 ml and 700-922 ml respectively for the 40 and 60 min arrest AL protocols, and 136 ml for the 60 min intermittent lido group. At 38 min or 58 min arrest, the coronary vascular resistance (CVR) was not significantly different for the AL arrested hearts and ranged between 0.27-0.32 megadyne.sec.cm-5. Significantly higher CVR’s were found in the lido cardioplegia group. No significant differences were found between the continuous or intermittent delivery protocols. AL hearts recovered 88% of aortic flow and 109% of coronary flow at 60 min reperfusion after 40 min arrest, and 76-86% of aortic flow and 98-109% of coronary flow at 60 min reperfusion after 60 min arrest. Lido cardioplegia delivered intermittently led to significantly lower aortic and coronary flows after 60 min arrest compared to the corresponding AL group.
Conclusions: We conclude that AL cardioplegia can be delivered intermittently or continuously with similar functional recoveries following 40 or 60 min arrest at 33°C. Hearts receiving lido cardioplegia took a significantly longer time to arrest, showed higher CVR’s and achieved lower functional recovery than the 60 min intermittent AL cardioplegia groups. Intermittent delivery of AL cardioplegia may offer a strategic alternative to current surgical hyperkalemic cardioplegia at warm to normothermic temperatures.
