Cardioprotection with Adenosine during Coronary Revascularization

Background: Postoperative cardiac dysfunction is a common cause of mortality and morbidity
associated with CABG Surgery. Adenosine enhances tolerance of the myocardium to ischemic
arrest. Therefore, the study on adenosine pre-treatment as an adjunct to cardioplegia in patients
undergoing CABG will definitely help to provide better myocardial protection for better postoperative
outcome.
Methods: Quasi experimental study was done in the Department of Cardiac Surgery, NICVD during
July 2012 to June 2014 with patients who underwent conventional CABG surgery. Patients were
divided in two groups. Group A: Patients received at regular institutional high-potassium ([K+] =
20 mol/ l) cold (12 °C) blood cardioplegia. and Group B: Patients received 250 µg /kg bolus dose of
adenosine pre-treatment, which was immediately followed by high-potassium cold (12 °C) blood
cardioplegia after clamp-on. Patients were followed up to evaluate the degree of myocardial damage
by measuring perioperative Troponin I, amount of inotropic support, time of assisted ventilation,
arrhythmia and mortality.
Results: Most of the patients in each group belongs to 51-60 years of age range. There was no
difference regarding operative parameters in two groups. Time to arrest was significantly shorter in
group B compared to group A, indicating that adenosine has the potential to enhance the efficacy of
cardioplegic arrest. Plasma level markers of myocardial damage: cardiac Troponin I (cTnI) obtained
from serial venous blood samples post-operatively were significantly lower in group B than group A
(p<0.05). There was significantly decreased requirement of inotrope in group B during first 24 hrs
(p <0.05).
Conclusion: Decreased level of cardiac enzymes and lower inotropic requirement suggests that an
optimal myocardial protection with less cellular damage is obtained with adenosine pre-treatment
as adjunct to cold blood cardioplegia.