Introduction
Cardioplegia is an essential cardioprotective pharmacological therapy
for electromechanical cardiac arrest during cardiac
surgery(1). This is achieved by altering cellular
electrochemical gradients to reduce myocardial metabolic demands by
inducing electrical quiescence. In addition, cooling of the myocardium
to minimise ischaemia-reperfusion (I-R) injury associated with being on
cardiopulmonary bypass, which is a significant cause of mortality and
morbidity in cardiac surgery(2). As well as myocardial
protection, cardioplegia is also indicated for a bloodless and
motionless operating field for prolonged periods of time.
There are many forms of cardioplegia that are currently used in clinical
practice; this can be classified based on varying parameters such as
temperature (cold, tepid or warm), solution (crystalloid or blood),
delivery method (anterograde, retrograde or combined) and substances
within the solution (glucose with insulin and potassium,
Mg2+, HCO3-,
procaine etc.). This suggests that there are probably several methods to
arrest the myocardium safely, prior to aortic cross-clamping.
Nevertheless, there is still an ongoing debate on the relative
effectiveness of these variable forms of cardioplegia.
Literature Search:
A comprehensive literature search was done on PubMed, SCOPUS, Embase,
Cochrane database, google scholar and Ovid to identify the articles that
discussed the use of myocardial protection methods during open heart
surgery. Key words used were ‘Cardioplegia’ ‘blood cardioplegia’
‘crystalloid cardioplegia’ ‘warm cardioplegia’ ‘cold cardioplegia’
‘myocardial protection’ ‘cardioplegia solutions’ ‘antegrade’
‘retrograde’. The search terms were used as key word and in combination
as MeSH terms to maximize the output from literature findings. A staged
literature search was done, whereby a separate literature search was
performed for each section within this article and all the relevant
studies were identified and summarized separately. If a paper is
reporting on many aspects of the myocardial protection, then the results
have been shared between different parts of this review. The relevant
articles are cited and referenced within each section separately. No
limit placed on publication time or language of the article.